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optidiscic
06-13-2010, 04:37 AM
Have been trying to understand disc technology as once I understand how something works I am better able to understand how to use it. I am one of those guys who needs to know how something works in order to use it properly.
What I really want to know is what disc features contribute to different flight characteristics.
SPEED
GLIDE
TURN
FADE
Stability


I know about wind, disc weight and arm speed and am getting sick of technique advice when I simply am CURIOUS about why certain discs do what they do

I realize theres a relationship between stability and glide (not absolute though see Viper, ROC and Wolf) What's the secret ingedient here with the oddballs?

Basically what disc features contribute to different disc flights.

I know this will be boring to most (I apologize)and others will not be able to control themselves and will contribute technique and disc choice advice...(I forgive you) and others will attempt to Hi-Jack this thread into the landfill (I neither apologize nor forgive you) but understanding why discs do what they do has helped my game tremendously and I often marvel at old pros who can pick up a worn disc with no markings or clue what disc it is other than the shape and features and be able to tell me how it will fly.

Thanks in advance

wolito
06-13-2010, 07:22 AM
I certianly don't know enough about discs in order to answer your questions, but rather would liketo say I share your fascination about how disc truly work. Afterall, it is the main component of our game. You certianly addressed it to the right people to answer it. I look forward to the answers.

jrawk
06-13-2010, 10:16 AM
Understable is a disc golf term that means glide (or force of lift generated) in flight mechanics. Just because a wolf wants to turn into the ground doesn't mean it isn't trying to glide. It's just lifting itself so severely it causes it to fall off a flat axis and turn over.

quoted for the truth.

harr0140
06-13-2010, 10:27 AM
Have been trying to understand disc technology as once I understand how something works I am better able to understand how to use it. I am one of those guys who needs to know how something works in order to use it properly.
What I really want to know is what disc features contribute to different flight characteristics.
SPEED
GLIDE
TURN
FADE
Stability


I know about wind, disc weight and arm speed and am getting sick of technique advice when I simply am CURIOUS about why certain discs do what they do

I realize theres a relationship between stability and glide (not absolute though see Viper, ROC and Wolf) What's the secret ingedient here with the oddballs?

Basically what disc features contribute to different disc flights.

I know this will be boring to most (I apologize)and others will not be able to control themselves and will contribute technique and disc choice advice...(I forgive you) and others will attempt to Hi-Jack this thread into the landfill (I neither apologize nor forgive you) but understanding why discs do what they do has helped my game tremendously and I often marvel at old pros who can pick up a worn disc with no markings or clue what disc it is other than the shape and features and be able to tell me how it will fly.

Thanks in advance

I have wondered the same things and also how the differetn plastic relate to stability and other flight patterns.

Good question!

garublador
06-13-2010, 10:54 AM
I know this will be boring to most (I apologize)and others will not be able to control themselves and will contribute technique and disc choice advice...(I forgive you) First, you'll never get the answers you're looking for by trying to sepearate disc flight charictaristics and technique. You need to throw the discs to get them to fly. Without technique the discs just sit there.

Second, I'm not sure I really understand the question. Are you asking how physical features of the discs affect flight or are you asking for the definitions of those terms listed above or some combination where you're looking for what physical features cause changes in the terms?

I can take a stab at it, though.

Speed is the easiest to define but not understood by many very well. It's a disc's ability to resist slowing down. That means it penetrates better into headwinds, retains stability into headwinds/at higher initial speeds and requires a faster initial speed to match it's given stability ratings (so it depends on technique). It is not a measurement of how fast it comes out of your hand. Generally, speed is inversely perportional to how fast a disc comes out of your hand. Wider rimmed discs are almost always higher speed than narrower rimmed discs.

Glide has a couple definitions. It can be a measurement of how well the discs "resists" fade (how late in the flight the disc fades) or it can be a measurement of how well a disc maintains altitude. A Sabre has lots of glide by the first definition (it fades super late) but little glide based on the second definition (it requires lots of height to go far). IMO, it's mostly a marketing number that doesn't really mean a whole lot. Notice that Joe's Flight Chart doesn't have a "glide" rating. My interpretation of Innvoa's "glide" rating is that it's a range rating for a given speed. More "glide" per speed means more distance if thrown right. Even Innova isn't separating technique from these ratings.

Turn is how well a disc resists high speed turn. There is a feature of turn that's rarely quantified where some discs turn gradually more and more as you throw them faster and faster (Eagle, Gazelle, OLF) and some go from straight to flipping hard rather quickly (Sidewinder, Archangel). The Teebird is weird because it's in the second category, but the speed required to get it to flip is super high, but the speed to get it to turn is relatively low.

The most common definition of fade is how far off line the disc fades at the end of its flight. There's a grey area between fade and glide. Some consider fade when a disc fades, too, so that kind of overlaps with one definition of glide.

Stability is kind of an ambiguous term. When I use it by itself, (e.g. a stable putter or a stable midrange) I mean a disc with stabilizing features (notches, beads) that have similar high speed stabilites for a high range of initial speeds.

So, in your other thread, where you talk about how the Wolf is understable but with little "glide" you're basically only looking at an understable disc that doesn't go very far. Going by another definition of glide (late fade for exapmle) it has a ton of glide. It's just difficult to throw it to get that glide out of it. Really, disc flight is way more complicated than 4-5 numbers. These ratings are only there to give you a general idea of how they'll fly compared to other discs. How they're thrown will have a very large effect on how the discs fly, so eigher only looking at disc ratings or only looking at technique will not get you the full picture of how a disc performs. Descriptions of how a disc performs coupled with technique will give you, by far, the most accurate information about the disc.

If you're looking for the physics of how certain disc features affect these ratings, I think you addressed your letter to at least one wrong person. I know very little about aerodynamics.

Frank Delicious
06-13-2010, 10:56 AM
Speed: how much spin and snap must be put on the disc to get it up to cruising speed. Weight of the rim and how ballistic the rim shape is usually contributes to the speed of the disc.

Glide: from what I understand (I wish JHern was over here, he knows a lot about disc physics) it has to do with how much and how air is trapped under the disc. This is why domey discs have more glide than flat discs. I am sure there is more to it than that but that is all I got

Turn: dunno probably has something to do with the aerodynamics of the profile of the disc.

Fade: lots of factors can contribute to fade: distribution of weight on the disc, notches on the rim, beads on the bottom, speed of the disc thrown, snap imparted onto the disc. Discs that have more weight on the rim, beads on the bottom and rim notches will generally fade harder than discs that don't have those things.

Stability: See speed and fade

Frank Delicious
06-13-2010, 10:57 AM
I don't really know if I answered the questions correctly but there ya go. They are hard to separate out. they are all intertwined

edit: I see that Garu beat me to it and wrote more.

billnchristy
06-13-2010, 11:54 AM
Welcome back Frank.

Craton
06-13-2010, 12:04 PM
Well, I just want to add my two cents: the guy is asking about physical features- NOT about form, NOT about definitions. He's asking the science about what specifically in a discs composition makes it do what it does.
A possible contribution to this discussion would be, from my understanding, something like "A bead on a wasp makes it more stable than the buzzz because (scientificy reason provied here)"- NOT "A bead on a wasp is what makes it more stable than a buzzz." He's asking the why. Don't get caught up in the whole "but it's about technique"- that's already an unspoken. He's talking pure physics right now- what separates one mold from another in terms of physics, not just observable characteristics (i.e. this one's got a wider rim).

KMaC
06-13-2010, 12:06 PM
I am also very confused as to what the question is.

What exactly do you want to know?

NateDiscFlip
06-13-2010, 12:20 PM
The discs that seem to amaze me are....

APX putter....filthy ability to glide and hold air....and very very str8

Tracker elite X & ESP....superior length and str8...very easy to work and very forgiving

Stalker: The nastiest disc in the game....just buy one! (I throw all my discs away and keep this one)....the disc's design is alien technology

Surge SS....similar properties as the stalker and tracker....but more speed like a wraith(not quite as fast...but fast)....best true driver in the game...disc does most any shot well

Katana.....rewriting the rules to shots I never thought of pulling off.....distance shots that finish tight

gl...:thmbup:

Craton
06-13-2010, 12:35 PM
The discs that seem to amaze me are....

APX putter....filthy ability to glide and hold air....and very very str8

Tracker elite X & ESP....superior length and str8...very easy to work and very forgiving

Stalker: The nastiest disc in the game....just buy one! (I throw all my discs away and keep this one)....the disc's design is alien technology

Surge SS....similar properties as the stalker and tracker....but more speed like a wraith(not quite as fast...but fast)....best true driver in the game...disc does most any shot well

Katana.....rewriting the rules to shots I never thought of pulling off.....distance shots that finish tight

gl...:thmbup:

I think of everyone, NateDiscFlip was THE most confused as to what the question was. Either that, or he posted on the wrong post.

himynameismatt
06-13-2010, 01:47 PM
He's asking which physical characteristics of the actual discs cause them to fly the way they do. So yeah it's an aerodynamics/physics question...I'm interested to hear an answer =D

NateDiscFlip
06-13-2010, 02:23 PM
let me try this again then...

fat edge(monster)....stability

wide wing with small swoop(destroyer)... speed, lift, stability, and huge turnover

flat wing with no swoop(surgeSS/tracker)...control(str8 flight)/small turnover...soft landing

curve wing(avenger)(usually ideal for tomahawks)....str8 shot, predictable finish

curve wing with thin edge(flash)....very str8....soft finish

Then there is the wind versions of discs....firebird, Viking, T-Rex, X-caliber

Lithicon
06-13-2010, 02:31 PM
He doesn't know what he's talking about, just let him rant and he'll go away eventually.

Btw, knowing the aerodynamics and how they affect flight, aren't going to make you a better player. It really won't matter unless you ever decide to make disc for yourself. Because really this won't help you throw a disc period.

harr0140
06-13-2010, 02:41 PM
He doesn't know what he's talking about, just let him rant and he'll go away eventually.

Btw, knowing the aerodynamics and how they affect flight, aren't going to make you a better player. It really won't matter unless you ever decide to make disc for yourself. Because really this won't help you throw a disc period.

Not true! If you are intelligent enough to understand the characteristics you will make better decisions in the field than someone who is oblivious to those differences. Most people just throw a disc they like, when it may not be the best choice. As long as you know what the disc is gonna do, that is the only key, but I think understanding why discs fly the way they do will help make good decisions.

garublador
06-13-2010, 02:48 PM
Not true! If you are intelligent enough to understand the characteristics you will make better decisions in the field than someone who is oblivious to those differences. Most people just throw a disc they like, when it may not be the best choice. As long as you know what the disc is gonna do, that is the only key, but I think understanding why discs fly the way they do will help make good decisions.Understanding what charictaristics are desireable is important, understanding why certain features give discs certain charictaristcs won't help. I see no problem with discussing it, though.

Pink Elephant
06-13-2010, 02:51 PM
Did no one else find it amusing he called Garu "Garubladder"?

garublador
06-13-2010, 02:53 PM
Did no one else find it amusing he called Garu "Garubladder"?I didn't even notice until now. That's my new favorite misspelling.

NateDiscFlip
06-13-2010, 03:38 PM
Hey buddy!....apparently you are losing some merit points by trying to constantly overthink and out think everyone on this site...slow down bro!

in the meantime...trust the disc...don't trust me...what do I know? right!

but just to counter your argument...I give my boy a star Katana yesterday...he has two birdie runs at holes he has never had runs at before...

my boy is very consistent...but he swore by the disc

wants some advice lithi?...get a stalker...and quite trying to be so smart...considering you are starting to sound like that one guy NATE:hfive::popcorn:

Pink Elephant
06-13-2010, 03:40 PM
He has a stalker *points at you*

Jukeshoe
06-13-2010, 03:40 PM
Did no one else find it amusing he called Garu "Garubladder"?

Good eye. :hfive:

racer93
06-13-2010, 03:41 PM
I read a blurb recently about pitchers throwing curve balls. This has to do with understability in that the same principle applies, at least to beat discs. It's called the "M____ Effect" (can't remember the name of it), but it says that the air pressure differs and causes the ball to move to the lower air pressure area and the disc's wing with the lower air pressure (R for RHBH throw) to dip in that direction.

That's what I can add.

optidiscic
06-13-2010, 03:58 PM
my bad garublador....you may call me optidickis

as far as why I want to know...part curiousity and partly I do believe understanding what discs do and why will definetely lead to better decision-making...is it the magic bullet to success, absolutely not but I think it would help.

The problem is that every disc has so many different ingredients in different measures that understanding why a disc does what it does gets confusing

This is my belief system so far...feel free to shatter my belief system if you disagree

Glide (or lift) is related to air moving faster over the top of the disc than it does underneath or even to just larger diameter discs....(T-Bird, ROC) Flat tops have less glide as the air on top is moving closer to the speed as the underside (wolf/zone) while discs with bigger domes glide more as the air on top is moving much faster than the air underneath (spider?) Glide also is related to the weight of the disc which makes it react to gravity sooner of course. The best analogy when it comes to glide for me is to think of airplanes.....the heavy ones (180g discs)dont fly as easily as light ones(150g discs).....bi-planes rely on greater wing surface area (Tee Birds) Jets don't have as much glide (firebird)as propellor driven planes (archangel) For these reasons Firebirds tend to get their distance from intially cutting through the air and then fade hard due to lack of glide while archangels achieve their distance in the latter portions of their glidey flight.....obviously the lower glide discs do better in the wind than their glidey counterparts.

In my world glide simply keeps a disc in the air longer and thus allows more time for other disc characteristics to occur such as hi speed turn and then low speed fade....akin to throwing off a hill on a windless day...the disc can achieve its full flight characteristics as it is in the air longer....every disc eventually will fade out if given enough room.

Thats about what I think I know about glide

sidewinder22
06-13-2010, 04:05 PM
Stability is about the the relationship of the wing tip height(weight mass) to the overall disc height. Higher wing tip(mass) = more stability. Lower wing tip(mass) = less stability. A blunt edge doesn't necessarily relate to stability especially with putters.

Beads keep discs more stable because they deflect air turbulence from going under the disc better.

Straight wings are less stable than curved wings within the same mold because the straighter wing has more mass lower. You can still have overstable discs with straight wings like the Venom because the wing tip or mass is very high.

Glide typically comes from the amount of air the disc can hold under it, so domes, larger diameter and deeper rims hold more air and glide better.

Fade and turn are generally related to the stability or weight distribution.

Rim width deals with disc speed.

Lithicon
06-13-2010, 04:12 PM
Not true! If you are intelligent enough to understand the characteristics you will make better decisions in the field than someone who is oblivious to those differences. Most people just throw a disc they like, when it may not be the best choice. As long as you know what the disc is gonna do, that is the only key, but I think understanding why discs fly the way they do will help make good decisions.

Like Garu said, it won't help.

Your decision to throw a disc because a wing angle of X* makes it less stable, than a disc with X.XX* of wing angle for a particular anhyzer shot doesn't mean it will perform that shot any better, if you don't have technique to make it work, lol. Also, ask any pro how much they understand about disc physics and I'd say in terms of our classifications of terms we apply to them, they have a great understanding. But, in a scientific terms I'd be willing to bet that most of them don't know, and don't care.

Because, after practicing with a disc they'll get an idea of how the disc will perform in their hands. Understanding which disc perform better could make you come to a conclusion of which disc just might be better suited to make a particular shot, or be more versatile. But, everyone else can get that knowledge much easier by practice, lol. Over thinking some things lead to failure. Determining which disc to pull out because of it's profile, or wing angles, or dome really isn't any different than saying. Well, this particular shot I can make my Roc flip just enough, "BING, use a Roc." One method is just easier and the other won't have that much affect over the competition as long as they know how and why to perform a certain shot in a given condition with a particular disc without knowing the small nuances of scientific physics of flight.

All this is trumped by your physical and mental capacity to perform the shot. Having the knowledge of how to throw certain lines, how to manipulate your form. And, then ultimately in the end being able to physically perform the shot. The variables in your throw you have to over come can make or break the throw completely. The throw could make the disc work or not. Knowing you could perform the shot, you could argue that you might not know what disc to throw just because you know how to throw, and can. Well, understanding the scientific physics won't make that much easier, as I said earlier anyone can get that knowledge easier by practice.

Over all the knowledge gained by the scientific data from how or why a disc flies the way it does, it trumped by your physical ability to perform the shot. Looks good on paper, and in your head. But, until you can go out and do it, it won't make a bit of difference. Then you can explain why it done it to someone, and they'll look at you and laugh. I do fully understand the search for knowledge. I like to know how things work myself.

As far as discussing it, I wasn't saying you shouldn't. I added my opinion to the discussion.

Oh, and Nate. You made two post that didn't even pertain to the topic. You're saying I'm losing credibility. Seriously, I didn't know I ever had any? It's an internet forum, honestly I have as much as you if the person wants to believe it. Most people with common sense though can see you're an idiot. :sick:

NateDiscFlip
06-13-2010, 04:36 PM
Lithi, Lithi, He's our man...if he can't explain it...no one can...especially natediscflip.

Lithi...you sound more intelligent when you're not trying to look so good, but thanks for the compliment.

by the way, by pointing out that people who understand how discs fly doesn't help their decision making and overall game....LOL...guy....that's why you bragg about throwing a putter 350....no one else cares...but you

as if trying to tell the guy who posted this thread that it is in his best to be able to throw a putter 350...or better yet...knowing how disc characteristics are of no concern....what game are you playing anyways?...here's a hint "antagonist"

You think cause you type, you can play...will someone post that this guy is as good as he can type PLEASE!! and I know I can out play you and your 350 putter drives...go work on your game son...chow

Lithicon
06-13-2010, 04:54 PM
Just because you can't read and understand the post I make because they aren't written in idiot speak, doesn't mean I don't know what I'm talking about. If you could read and understand I didn't say that understanding disc flight doesn't help, I said scientific physics of disc flight won't help them as much as they want to think it will. Also never said that disc characteristics weren't of concern. Again, you can't read and comprehend, not my fault.

My game is terrible lately, I won't deny that. But, my game is only a reflection of my dedication to practice, not a reflection of my knowledge of the game.

optidiscic
06-13-2010, 04:54 PM
PLease take the flame war somewhere else...I don't want this thread going landfill or closed...

OK speed as it pertains to flightspeed is affected by a lower profile (less resistance) and weight to the outside of a disc generating more momentum and thus thrusting a disc forward. (ION and fatty rimmed drivers) A low profile fat rimmed driver is probably the fastest disc u can find. The problem is snap is required to get that fat rim moving....lesser players can't generate that snap to keep the disc moving forward...I would guess the difference between a 300 foot throw and a 500 foot throw could be that in the first 300 feet of each throw the farther throw will have far more revolutions

KMaC
06-13-2010, 04:57 PM
in the meantime...trust the disc...don't trust me...what do I know? right!

Quoted for truth.

NateDiscFlip
06-13-2010, 05:06 PM
PLease take the flame war somewhere else...I don't want this thread going landfill or closed...

OK speed as it pertains to flightspeed is affected by a lower profile (less resistance) and weight to the outside of a disc generating more momentum and thus thrusting a disc forward. (ION and fatty rimmed drivers) A low profile fat rimmed driver is probably the fastest disc u can find. The problem is snap is required to get that fat rim moving....lesser players can't generate that snap to keep the disc moving forward...I would guess the difference between a 300 foot throw and a 500 foot throw could be that in the first 300 feet of each throw the farther throw will have far more revolutions


Sorry opti....but as history has it...the trolls can help themselves without giving insult...I posted....made a bad post...and corrected it....then Einstein and Beavis jump...

Too bad...I thought I had some good information to share...but can't seem to avoid the egohaters...i'll keep posting my bad info...sorry...and stay away from the insignificants who think they know it all...

biscoe
06-13-2010, 05:06 PM
The problem is snap is required to get that fat rim moving....lesser players can't generate that snap to keep the disc moving forward...I would guess the difference between a 300 foot throw and a 500 foot throw could be that in the first 300 feet of each throw the farther throw will have far more revolutions

snap is required to KEEP it moving. armspeed is required to get it moving.

Lithicon
06-13-2010, 05:09 PM
Yes, the wider rim drivers are harder to gain snap, AND, require more snap than a smaller rimmed driver to attain the same or more distances generally speaking. That's why people throwing roughly 400' with fairway drivers and pick up a Boss, Destroyer, Groove, Katana, Nuke, don't see much of a distance increase as they can't generate more snap on the disc to get the correct flight out of it. Regardless if they can get it close to it's cruising speed.

Lithicon
06-13-2010, 05:17 PM
Guess I could add this, as the more weight is on the outside of the disc as you mentioned it takes more snap to get it spinning the same as disc with less weight on the outside. BUT, can maintain that spin longer if enough spin is applied than the disc that have less mass on the outside. This is where speed affects the flight as the stability of the disc is less affected by the speed because of the amount of spin it takes to get the wider rim disc going, which coins the phrase speed stable. The disc with less weight on the outside can be more affected by speed and therefore become less stable faster, because as the spin slows down normally in flight, the disc will be overcome by speed.

But, spin can make the disc more or less stable longer, as the gyro effect will allow it to maintain the correct plane longer or shorter depending upon the amount of spin the disc has.

This applies to Over stable, and under stable.

As you can make a more over stable disc fade less if you're able to put enough spin on it, but it's much harder to do than keeping a less stable disc from turning.

VictorB
06-13-2010, 05:22 PM
Angular velocity [av] (spin imparted on a disc at release) is the what keeps a disc "holding a line" - whether that be hyzer, straight, or turnover. Moment of inertia [mi] determines the force that is needed to get a disc spinning.

Directional velocity [dv] is the forward speed of a disc. Each disc requires a certain directional velocity to fly properly. If the dv:av ratio is very high, the disc will act understable. if the dv:av ratio is low, the disc will act more overstable than it really is.

Lift is the force generated by air passing faster over the flight plate when compared to the under side of the disc. The differences in air speed passing the disc cause a slight difference in air pressure - with the higher pressures being applied to the underside of the disc - creating a slight upward force that works against gravity. This is also known (somewhat incorrectly) as glide.

Stability is a rating based on the ability for a disc to keep it's center of pressure (where the lift force is applied to the disc) close to the true center of the flight plate. Overstable discs tend to have a center of pressure on the on the right side that the disc, thus the disc wants to lift it's wing on the right side (RHBH throwers). The opposite is true for understable discs, but given enough time in the air, the center of pressure will move back to the right side of the disc, causing the right wing to lift. (see JHern's thread on dgr for an illustrative reference) Stable discs tend to balance the center of pressure better than the other two categories, and therefore fly on truer lines than the other two.


I'd add more, but am a little lost for what to explain next...others have probably explained the above in a better manner than I can.

I'll add more when I have a bit more time.

VictorB
06-13-2010, 05:26 PM
Guess I could add this, as the more weight is on the outside of the disc as you mentioned it takes more snap to get it spinning the same as disc with less weight on the outside. BUT, can maintain that spin longer if enough spin is applied than the disc that have less mass on the outside.

Yes, this is called the moment of inertia. Once you meet the inertial force requirements to get a disc to spin faster (creating the proper centrifugal force for the distribution of weight), it will try to hold the angular momentum imparted on the disc longer. Once the momentum slows though, there will be a drastic movement of the center of pressure over to the right (RHBH throwers) and generally a strong fade at the end of the flight.

optidiscic
06-13-2010, 05:26 PM
Lets talk about that momentum of the disc:

If a RHBH drive is made with a fat rimmed driver with a lot of snap then the left side of the disc will actually have more air moving over the top of the disc due to the disc moving against the air while the right side will move the same direction with the air. This is why initially all discs tend to be less stable in their flights. The increased air movement over the top of the disc on the left side of the disc causes the left side to lift and the disc begins it's turn as the revolutions decrease the disc flattens out and eventually they slow to the point where the momentum of the left side dropping will cause the disc to fade.....this is why the fatter a rim is the harder the fade will be and this contributes to increased fade. To throw a disc straight requires matching flightspeed and spinspeed in the perfect balance. Easier to do with thinner rimmed (slower) discs.

NateDiscFlip
06-13-2010, 05:29 PM
Guess I could add this, as the more weight is on the outside of the disc as you mentioned it takes more snap to get it spinning the same as disc with less weight on the outside. BUT, can maintain that spin longer if enough spin is applied than the disc that have less mass on the outside. This is where speed affects the flight as the stability of the disc is less affected by the speed because of the amount of spin it takes to get the wider rim disc going, which coins the phrase speed stable. The disc with less weight on the outside can be more affected by speed and therefore become less stable faster, because as the spin slows down normally in flight, the disc will be overcome by speed.

But, spin can make the disc more or less stable longer, as the gyro effect will allow it to maintain the correct plane longer or shorter depending upon the amount of spin the disc has.

This applies to Over stable, and under stable.

As you can make a more over stable disc fade less if you're able to put enough spin on it, but it's much harder to do than keeping a less stable disc from turning.

Sorry but more spin equals larger skip...unless you give it air....not sure of the point of providing the comment, since it is a shot no one is going to use

Lithicon
06-13-2010, 05:30 PM
Angular velocity [av] (spin imparted on a disc at release) is the what keeps a disc "holding a line" - whether that be hyzer, straight, or turnover. Moment of inertia [mi] determines the force that is needed to get a disc spinning.

Directional velocity [dv] is the forward speed of a disc. Each disc requires a certain directional velocity to fly properly. If the dv:av ratio is very high, the disc will act understable. if the dv:av ratio is low, the disc will act more overstable than it really is.

Lift is the force generated by air passing faster over the flight plate when compared to the under side of the disc. The differences in air speed passing the disc cause a slight difference in air pressure - with the higher pressures being applied to the underside of the disc - creating a slight upward force that works against gravity. This is also known (somewhat incorrectly) as glide.

Stability is a rating based on the ability for a disc to keep it's center of pressure (where the lift force is applied to the disc) close to the true center of the flight plate. Overstable discs tend to have a center of pressure on the on the right side that the disc, thus the disc wants to lift it's wing on the right side (RHBH throwers). The opposite is true for understable discs, but given enough time in the air, the center of pressure will move back to the right side of the disc, causing the right wing to lift. (see JHern's thread on dgr for an illustrative reference) Stable discs tend to balance the center of pressure better than the other two categories, and therefore fly on truer lines than the other two.


I'd add more, but am a little lost for what to explain next...others have probably explained the above in a better manner than I can.

I'll add more when I have a bit more time.

The part highlighted above is essentially what I was saying in my post above.

NateDiscFlip
06-13-2010, 05:36 PM
fly PROPERLY....this is where you are getting your explanation all funny....what designates a proper throw...besides aces? Make sense...not words...oh you must mean OAT

Lithicon
06-13-2010, 05:37 PM
Sorry but more spin equals larger skip...unless you give it air....not sure of the point of providing the comment, since it is a shot no one is going to use

Spin could affect distance after the skip whether it be a intentional or unintentional skip. Just like it affects distance period. But, I really don't see how skip pertained to my post, as just because you put more spin on a disc doesn't mean it will skip if that's what you're referring to. Also unable to gather which shot you're referring to no one using.

optidiscic
06-13-2010, 05:39 PM
So for all intents and purposes a fat rimmed disc will fight back to fade in the end of it's flight regardless ....this is why sidewinders and roadrunners tend to have less fade..they are not fat rimmed discs and the discs will not fight back as much when they slow down because the left side of the disc will not fall as much creating a hyzer angle.

Lithicon
06-13-2010, 05:41 PM
Yes, but I'm pretty positive there is a little more to it than just the fact those disc aren't wide rimmed.
As explained by Victor.

Jukeshoe
06-13-2010, 05:42 PM
go work on your game son...chow

chow=ciao?

Go work on your Italian...:D

Lithicon
06-13-2010, 05:44 PM
fly PROPERLY....this is where you are getting your explanation all funny....what designates a proper throw...besides aces? Make sense...not words...oh you must mean OAT

:thmbup: Please go back to reading your post before you submit them.

Aces have nothing to do with a proper throw, hahaha. Not even sure where OAT comes into this other than referring to your lucky ace.

optidiscic
06-13-2010, 05:49 PM
Yes, but I'm pretty positive there is a little more to it than just the fact those disc aren't wide rimmed.

someone once mentioned that the more a fat rimmed driver turns that the more it will fade....he said this as he was explaining to a newer player why a flex shot was a better situational shot and not a wise choice for distance. The switch in momentum from an artificial turn (OAT) to a hard fade is more drastic when there is not as much spin to keep the disc moving forward...thus a player with little snap throwing a fat rimmed disc will end up with a dramatic s turn as the disc does not get pushed forward by spin and the switch from anhyzer angle to hyzer is much more dramatic as the disc revolutions are so low.

optidiscic
06-13-2010, 05:57 PM
Stability is about the the relationship of the wing tip height(weight mass) to the overall disc height. Higher wing tip(mass) = more stability. Lower wing tip(mass) = less stability. A blunt edge doesn't necessarily relate to stability especially with putters.

Beads keep discs more stable because they deflect air turbulence from going under the disc better.

Straight wings are less stable than curved wings within the same mold because the straighter wing has more mass lower. You can still have overstable discs with straight wings like the Venom because the wing tip or mass is very high.


Can someone try to explain this to me...I'm dumb but still curious

NateDiscFlip
06-13-2010, 05:59 PM
:thmbup: Please go back to reading your post before you submit them.

Aces have nothing to do with a proper throw, hahaha. Not even sure where OAT comes into this other than referring to your lucky ace.

Lol....guy...I can manipulate a wide rim disc without the use of snap....but you think everything is in some text book...keep on knowing everything...no wonder you say your game is weak...the best players...are the best learners...and you are far from letting anything pass through the discdome you speak so highly of having

Snap works best in wind situations since the disc is able to cut through the air better...how about them apples?...no snap...wide rim...wind...disc go bye bye....

I try to tell my students like I will tell you grasshopper...snap is later...first learn technique....and watch the LithiconDiscGolfShow too

discpicable
06-13-2010, 06:12 PM
snap is later...first learn technique....

..............:|

hewittdallas
06-13-2010, 06:17 PM
This thread would be worth reading if I could block people...

discpicable
06-13-2010, 06:20 PM
This thread would be worth reading if I could block people...

You can.

optidiscic
06-13-2010, 06:23 PM
I understand that the more a disc spins the more understable it becomes as there is a difference in air flows from R to L sides of the disc and thus lift causes the disc to eventually go on an in flight anhyzer angle.....Every disc in theory can be flipped(turned) if enough spin is generated.
I still would like to hear more about the bead and wing shape stuff if someone can explain that it would help..thanks

optidiscic
06-13-2010, 06:29 PM
I particularly am confused how some narrow rimmed discs can be overstable

sidewinder22
06-13-2010, 06:30 PM
Stability is about the the relationship of the wing tip height(weight mass) to the overall disc height. Higher wing tip(mass) = more stability. Lower wing tip(mass) = less stability. A blunt edge doesn't necessarily relate to stability especially with putters.

Beads keep discs more stable because they deflect air turbulence from going under the disc better.

Straight wings are less stable than curved wings within the same mold because the straighter wing has more mass lower. You can still have overstable discs with straight wings like the Venom because the wing tip or mass is very high.


Can someone try to explain this to me...I'm dumb but still curious

Its about where the weight is distributed in the height of the disc. When looking at a disc profile the wing tip height is typically where most of the weight mass is. If the wing tip is higher than the center height of the disc, it will generally act overstable or be harder to move off axis. It the wing tip is lower than the center height it will generally act understable or be easier to move off axis.

Think of the difference between the center of gravity of men and women. Men have more mass above their center height and women have more mass below the center. Women are understable when it comes to flying. On the ground its a little different because women's lower center of gravity is more stable. If you suspend a man and woman, then push them with the same force on the center of their height, the man will come to rest quicker since the center of gravity is higher. The woman will keep moving longer with more pendulum action since the weight is lower.

Lithicon
06-13-2010, 06:30 PM
Yeah, that post is a prime example of why you're so highly revered. You're ass backwards in nearly everything you say. I told you many times I'm not beyond learning from anyone. I've learned a lot from you, just how dumb you really are. I've also learned that while you think I refuse to learn, it's actually you as what I've been teaching people here is pretty much accepted by most. You're the only one that refuses to accept that. You're what some people consider unteachable. But, when it comes to proper technique, it'd be a real cold day in hell before you'd have something I'd consider worth learning. That's why I don't accept you as my teacher, because I have someone that's better than you. :)

optidiscic
06-13-2010, 06:38 PM
Its about where the weight is distributed in the height of the disc. When looking at a disc profile the wing tip height is typically where most of the weight mass is. If the wing tip is higher than the center height of the disc, it will generally act overstable or be harder to move off axis. It the wing tip is lower than the center height it will generally act understable or be easier to move off axis.

OK I am visualizing this...but am still bewildered how it affects stability

Lithicon
06-13-2010, 06:40 PM
I understand that the more a disc spins(The higher cruising speed the disc reaches) the more understable it becomes as there is a difference in air flows from R to L sides of the disc and thus lift causes the disc to eventually go on an in flight anhyzer angle.....Every disc in theory can be flipped(turned) if enough spin(Cruising Speed) is generated.
I still would like to hear more about the bead and wing shape stuff if someone can explain that it would help..thanks

This is how it should read, spin doesn't increase turn. LESS spin with more speed increases turn. More spin reduces turn.

sidewinder22
06-13-2010, 06:45 PM
Its about where the weight is distributed in the height of the disc. When looking at a disc profile the wing tip height is typically where most of the weight mass is. If the wing tip is higher than the center height of the disc, it will generally act overstable or be harder to move off axis. It the wing tip is lower than the center height it will generally act understable or be easier to move off axis.

OK I am visualizing this...but am still bewildered how it affects stability

When the disc is flying RHBH, the lift comes from the left side of the disc. Having the weight higher on the right side is a better balance than if the weight is lower.

optidiscic
06-13-2010, 06:57 PM
This is how it should read, spin doesn't increase turn. LESS spin with more speed increases turn. More spin reduces turn.

I think I disagree. (respectfully) The higher rate of spin will cause a difference in lift between the R and L side of a disc. In a RHBH throw the right side of the disc will be moving in the same direction as the air it is cutting through, inversely, the L side of the disc will be moving against the air. A slight difference in air pressures below the disc will occur with more air moving over the top of the L side and thus there will be some lift on the L side and an in flight anhyzer angle is the result..as the disc slows it flattens out and eventually the momentum of the disc righting itself will cause the hyzer angle and the inevitable fade.

Spin will keep a disc moving forward as it is essentially the engine that keeps pushing the disc forward along with the power throw that the arm generates.

I don't think Spin is what keeps a disc straight...I think matching spin speed with flightspeed is what keeps a disc straight. That is you neither overpower or underpower the disc. Not enough spin to generate the turn and the disc flight ends before the disc has a chance to fade. A tee bird can achieve this due to it's large forgiving diameter that minimizes the differences in lift between the 2 sides of the disc.

optidiscic
06-13-2010, 06:58 PM
When the disc is flying RHBH, the lift comes from the left side of the disc. Having the weight higher on the right side is a better balance than if the weight is lower.

Bingo...thank you for crystalizing that for me! So a disc with a higher center of gravity is more stable...correct?

Frank Delicious
06-13-2010, 06:59 PM
This thread is pretty good once you skip Nate's posts. this is a good discussion going on.

ts about where the weight is distributed in the height of the disc. When looking at a disc profile the wing tip height is typically where most of the weight mass is. If the wing tip is higher than the center height of the disc, it will generally act overstable or be harder to move off axis. It the wing tip is lower than the center height it will generally act understable or be easier to move off axis.


I didn't know this. I am going to have to check this out. Putting beads on discs kinda seems counter-intuitive to this though.

BogeyNoMore
06-13-2010, 07:06 PM
Optidiscic - thanks for the OP and getting this going.

Directional velocity [dv] is the forward speed of a disc. Each disc requires a certain directional velocity to fly properly. If the dv:av ratio is very high, the disc will act understable. if the dv:av ratio is low, the disc will act more overstable than it really is.

VictorB - Thanks for the most succint and understandable explanation of Spin vs. Speed I've seen anywhere on this forum.

From what you've given, it would seem the ratio of [dv]:[av] is the major factor in determining a disc's stability - correct?

All other variables being held constant: greater velocity [dv] will make a disc behave more undertstably (most of us have experienced this for ourselves).

Conversely, if spin [av] is increased with no change to speed [dv] the disc will behave more stably.

When spin [av] increases along with velocity, the dv:av ratio remains relatively constant, which would allow throwing the same disc harder, without a significant change in flight charactersistics (although I'm not sure most of us can control [av] as well as we can control [dv]).

Further, overstable discs are designed to "handle" greater speed for a given amount of spin, while understable discs are designed for less.

THANKS!! :thmbup: That genuinely helps in understanding why discs behave as they do.

This thread is pretty good once you skip Nate's posts. this is a good discussion going on....agreed!

sidewinder22
06-13-2010, 07:08 PM
Bingo...thank you for crystalizing that for me! So a disc with a higher center of gravity is more stable...correct?

Yes, since we are dealing with lift in the turn phase of flight as opposed to gravity its the opposite of what happens on the ground.

Lithicon
06-13-2010, 07:12 PM
Yup, that's exactly how it should be interpreted. Which is what I said, but took more to explain because I'm not familiar with the physics terms to express it. He done a fantastic job.

Lithicon
06-13-2010, 07:15 PM
Yes, since we are dealing with lift in the turn phase of flight as opposed to gravity its the opposite of what happens on the ground.

I was actually going to say that earlier, but got side tracked with something else and didn't feel like posting it. That is the part that has always intrigued me, as it's just the opposite.

optidiscic
06-13-2010, 07:24 PM
I've heard that slicker plastics are faster due to the plastic molecules being closer together (this makes harder plastic)and air will pass across the surface faster / thus Champion is the hardest and fastest plastic INNOVA makes. If this is indeed true then I would guess that Champion plastic might fly differently than other plastics.

racer93
06-13-2010, 07:25 PM
This thread is pretty good once you skip Nate's posts. this is a good discussion going on.



I didn't know this. I am going to have to check this out. Putting beads on discs kinda seems counter-intuitive to this though.

Isn't this leading into a PLH discussion? Such as high PLH = Overstability and low PLH = Understability?

optidiscic
06-13-2010, 07:28 PM
what is PLH?

Lithicon
06-13-2010, 07:30 PM
I've heard that slicker plastics are faster due to the plastic molecules being closer together (this makes harder plastic)and air will pass across the surface faster / thus Champion is the hardest and fastest plastic INNOVA makes. If this is indeed true then I would guess that Champion plastic might fly differently than other plastics.

Yes, it makes it less affected by the air pressures around it, as it cuts through the air better. The air has less potential to affect it as the disc has less surface imperfections to manipulate the air causing the disc to be slightly less affected, and slower to react to those effects.

Racer was referring to the Parting line height, which is essentially what Sidewinder was talking about.

racer93
06-13-2010, 07:32 PM
what is PLH?

Parting Line Height. There are some good discussions of it already floating around here. Worth checking out.

optidiscic
06-13-2010, 07:32 PM
Yes, it makes it less affected by the air pressures around it, as it cuts through the air better. The air has less potential to affect it as the disc has less surface imperfections to manipulate the air causing the disc to be slightly less affected, and slower to react to those effects.

Would this explain why Champion discs seem to be the straighter flying discs or is that in my head?

racer93
06-13-2010, 07:33 PM
Racer was referring to the Parting line height...
Just making sure I was on the right page as I'm following along...:popcorn:

Lithicon
06-13-2010, 07:48 PM
I think I disagree. (respectfully) The higher rate of spin will cause a difference in lift between the R and L side of a disc. In a RHBH throw the right side of the disc will be moving in the same direction as the air it is cutting through, inversely, the L side of the disc will be moving against the air. A slight difference in air pressures below the disc will occur with more air moving over the top of the L side and thus there will be some lift on the L side and an in flight anhyzer angle is the result..as the disc slows it flattens out and eventually the momentum of the disc righting itself will cause the hyzer angle and the inevitable fade.

Spin will keep a disc moving forward as it is essentially the engine that keeps pushing the disc forward along with the power throw that the arm generates.

I don't think Spin is what keeps a disc straight...I think matching spin speed with flightspeed is what keeps a disc straight. That is you neither overpower or underpower the disc. Not enough spin to generate the turn and the disc flight ends before the disc has a chance to fade. A tee bird can achieve this due to it's large forgiving diameter that minimizes the differences in lift between the 2 sides of the disc.

Ooh, no need to say respectfully. You're not Nate, we're actually having a discussion, Nate just chimes in with idiocy. We're all respectful here. I'm not attacking anyone with these post, just sharing my opinions.

This is a pretty good point, but the speed is what makes the air pressure differences on the opposite sides from what I can gather.

And, yeah the spin will assist it moving forward as long with the speed the disc gained from the throw is sufficient to get it moving forward. Spin alone can't generate movement in any direction, unless the leading edge angle is not on a flat plane, which will then result in penetrating the way it's angled, along with whichever way the directional velocity is directed. If it's on a flat level plane, and is accelerated to a certain amount of spin, it would just sit there without some directional velocity to push it in a specific direction.

As from what I gather from the way it's been described, and the way Victor described it, Spin will always over power speed if enough spin is imparted on the disc. Which explains the 3 and 5 directional throws, which is spin and speed working themselves out of the throw at different rates, and causing the disc to behave a certain way as the result. But, I could be wrong, that's just how I've come to understand it.

Lithicon
06-13-2010, 07:52 PM
Would this explain why Champion discs seem to be the straighter flying discs or is that in my head?

Hrmm, I personally think it could assist in that aspect of flight, as it would be less affected by certain aspects. But, I'm thinking other aspects of how the disc is designed would be a greater impact on that, I'm not sure.

optidiscic
06-13-2010, 07:53 PM
yeah spin would move a disc backwards as much as forwards...silly me.

Olorin
06-13-2010, 08:03 PM
There's also lots of informative reading that will help you in the Physics of Flying Discs (http://www.dgcoursereview.com/forums/showthread.php?t=2250) thread. I think this is Brother Dave's favorite topic.

optidiscic
06-13-2010, 08:06 PM
I am imagining a disc with R-Pro plastic on the underside and champion plastic on top/sides... for improved grip and increased lift...I am guessing the combination of fast plastic on top and slow plastic underneath will produce unimagined glide and the good grip will allow for the most ideal grip and snap.

I will submit this patent and sell it to INNOVA and be rich the rest of mydays...as long as I don't blow it on plastic!

BrotherDave
06-13-2010, 08:11 PM
There's also lots of informative reading that will help you in the Physics of Flying Discs (http://www.dgcoursereview.com/forums/showthread.php?t=2250) thread. I think this is Brother Dave's favorite topic.

I was debating on digging that thread up for you guys. I've already tried to understand this stuff one time, I'll just sit in the corner and yo-yo.

Lithicon
06-13-2010, 08:11 PM
You know, honestly it's not quite the way most have envisioned that particular scenario with drivers. But, more along the reverse Ion type thing. Which, the way you describe it could be done too, same method also. R&D it and find out the results, from the physics stand points it sounds it'd be worthwhile. Would be hold up to real world testing, we'd have to see. I'd assume the majority of it would be largely based on the method and plastics used to join the two pieces.

Olorin
06-13-2010, 08:11 PM
It's called the "M____ Effect" (can't remember the name of it)...
That's the Magnus Effect. And it also affects the flight of spinning projectiles like bullets.

Lithicon
06-13-2010, 08:12 PM
I was debating on digging that thread up for you guys. I've already tried to understand this stuff one time, I'll just sit in the corner and yo-yo.

Aww, you just focus on throwing that disc of death in your avatar and it won't matter how we throw ours. Cause you can always make it to the basket in a straight line. :( Saddest part is, you'll probably take the basket out when you get there. :doh:

I debated finding that thread too, but wanted to see where this one went.

BrotherDave
06-13-2010, 08:13 PM
That's the Magnus Effect. And it also affects the flight of spinning projectiles like bullets.

Yeah, I heard of this on an episode of Sport Science where they determined that a soccer ball could be "bent" more than a curveball.

optidiscic
06-13-2010, 08:21 PM
so the bead pushes air away from the underside of the disc....how does this increase stability?

Olorin
06-13-2010, 08:21 PM
Angular velocity [av] (spin imparted on a disc at release) is the what keeps a disc "holding a line" - whether that be hyzer, straight, or turnover. Moment of inertia [mi] determines the force that is needed to get a disc spinning.

Directional velocity [dv] is the forward speed of a disc. Each disc requires a certain directional velocity to fly properly. If the dv:av ratio is very high, the disc will act understable. if the dv:av ratio is low, the disc will act more overstable than it really is.

I may be wrong, but I think that higher spin (AV) makes a disc more understable. That would mean that if you have 2 throws with the same disc at the same DV then the one with the higher AV would be more understable.

BrotherDave
06-13-2010, 08:22 PM
so the bead pushes air away from the underside of the disc....how does this increase stability?

I thought the bead just added friction/drag and hampered the velocity. :|

Olorin
06-13-2010, 08:24 PM
So for all intents and purposes a fat rimmed disc will fight back to fade in the end of it's flight regardless ....this is why sidewinders and roadrunners tend to have less fade..they are not fat rimmed discs and the discs will not fight back as much when they slow down because the left side of the disc will not fall as much creating a hyzer angle.
The size of the rim and the density of the plastic have a direct affect on gyroscopic stability, and this GS is a key component of the physics of flying discs.

optidiscic
06-13-2010, 08:25 PM
I may be wrong, but I think that higher spin (AV) makes a disc more understable. That would mean that if you have 2 throws with the same disc at the same DV then the one with the higher AV would be more understable.

Increased spin does indeed increase understability according to everything I have researched on this topic.

Olorin
06-13-2010, 08:28 PM
I understand that the more a disc spins the more understable it becomes as there is a difference in air flows from R to L sides of the disc and thus lift causes the disc to eventually go on an in flight anhyzer angle.....
This is a popular misconception, but it's not true. The actual aerodynamics are far more complicated than that. The reasons why a RHBH disc turns right still have not been adequately explained. There are many factors that increase the right turn and they're easy to list, but it's very complex to describe why they make the disc turn.

racer93
06-13-2010, 08:28 PM
That's the Magnus Effect. And it also affects the flight of spinning projectiles like bullets.

Thanks! I was too lazy to look it up myself...;)

racer93
06-13-2010, 08:30 PM
Increased spin does indeed increase understability according to everything I have researched on this topic.

In general, increased spin leads to more stability, meaning that the disc will stay straighter for a longer period of time during its flight. There are many, many variables to this. As I said, this is a glittering generality.

Lithicon
06-13-2010, 08:34 PM
Just like Victor described. And, I pointed out in one of my last posts. From everything I can gather, the speed is what makes the disc under stable along with it's physical dimensions. Spin will increase gyroscopic trueness reducing turn on ANY disc regardless of it's dimensions.

Just like a cd spinning 1000's of rpms, or a blade on a grinder, saw, or anything like that. If spin alone increased turn, then it would self destruct from turning inside the cd rom, and force the mechanics inside it to bend and break too. Wheels would try to turn and eventually rip off a car or bend the axles and such. All not really as good examples as the CD rom thing, but still.

Frank Delicious
06-13-2010, 08:35 PM
Also there was a good thread on DGR on it.

Here is a good post from it by JHern who has a PhD in physics:


I have to write a fairly extensive research paper on a sport for my Physics class and, of course, I chose disc golf. I have to write a paper that is at least 3 typed pages long explaining any 5 concepts of physics and how they are applied in disc golf. I also need to create charts, measurements, etc. for these concepts.
The five concepts I chose are air resistance, projectile motion, work, and Newton's First and Second Laws. These aren't necessarily set in stone though.

Anyway, DGC, I figured I'd leave a post here for anyone interested. If anyone knows of any information/resources that would be helpful I'd appreciate it! If not, maybe we can get an interesting discussion going.

Blake invited me to write up an article for DGR's front page on this topic, but I haven't worked on it for a while. I'll eventually get this finished. For now, I suggest you look up Sarah Hummel's thesis:

http://mae.ucdavis.edu/~biosport/frisbee/frisbee.html

This is some of the best material available online. Potts has put up some papers with beautiful streak-line experimental figures. Definitely check these out:

http://www.disc-wing.com/

Finally, be careful of material you see on the forums, much of it contains significant conceptual errors, and as the discussion evolves some of the information could easily be taken out of context.

Good luck!
JHern (Ph.D.)

optidiscic
06-13-2010, 08:36 PM
In general, increased spin leads to more stability, meaning that the disc will stay straighter for a longer period of time during its flight. There are many, many variables to this. As I said, this is a glittering generality.

I think many confuse resistance to fade with high spin which makes sense when saying spin keeps a disc straight but I still think more spin naturally leads to increased understabilty as well.

Lithicon
06-13-2010, 08:40 PM
Angular velocity [av] (spin imparted on a disc at release) is the what keeps a disc "holding a line" - whether that be hyzer, straight, or turnover. Moment of inertia [mi] determines the force that is needed to get a disc spinning.

Directional velocity [dv] is the forward speed of a disc. Each disc requires a certain directional velocity to fly properly. If the dv:av ratio is very high, the disc will act understable. if the dv:av ratio is low, the disc will act more overstable than it really is.

Lift is the force generated by air passing faster over the flight plate when compared to the under side of the disc. The differences in air speed passing the disc cause a slight difference in air pressure - with the higher pressures being applied to the underside of the disc - creating a slight upward force that works against gravity. This is also known (somewhat incorrectly) as glide.

Stability is a rating based on the ability for a disc to keep it's center of pressure (where the lift force is applied to the disc) close to the true center of the flight plate. Overstable discs tend to have a center of pressure on the on the right side that the disc, thus the disc wants to lift it's wing on the right side (RHBH throwers). The opposite is true for understable discs, but given enough time in the air, the center of pressure will move back to the right side of the disc, causing the right wing to lift. (see JHern's thread on dgr for an illustrative reference) Stable discs tend to balance the center of pressure better than the other two categories, and therefore fly on truer lines than the other two.


I'd add more, but am a little lost for what to explain next...others have probably explained the above in a better manner than I can.

I'll add more when I have a bit more time.

This is a popular misconception, but it's not true. The actual aerodynamics are far more complicated than that. The reasons why a RHBH disc turns right still have not been adequately explained. There are many factors that increase the right turn and they're easy to list, but it's very complex to describe why they make the disc turn.

This is a pretty good explanation of how and why disc will and won't turn.

Lithicon
06-13-2010, 08:44 PM
I think many confuse resistance to fade with high spin which makes sense when saying spin keeps a disc straight but I still think more spin naturally leads to increased understabilty as well.

Resistance to fade is due to more spin. Spin affects both over and under stable disc to retain stability. Stability is flat, true plane. There levels of stability, over stable, stable, and under stable. Spin will keep the disc in the middle.

Take any object designed to spin, make it spin faster and faster, it won't do anything but sit there and spin. UNTIL an outside force, such as direction velocity(speed), and angles of release or such are applied to it. The faster it's allowed to spin, coupled with the speed at which it's moving in a given direction it will fight to maintain that axis longer.

bikinjack
06-13-2010, 08:55 PM
Resistance to fade is due to more spin. Spin affects both over and under stable disc to retain stability. Stability is flat, true plane. There levels of stability, over stable, stable, and under stable. Spin will keep the disc in the middle.

Actually, spin is part of what causes the disc to fade at the end of its flight. This is due to precession. The center of lift for a disc is in front of (relative to the direction of velocity) the center of rotation. This causes the disc to rotate nose up as it flies, and that rotation in turn causes the disc to want to fade (to the right for a RHBH throw) due to angular momentum. This effect is called precession.

I still don't understand why a disc turns to the right in the high speed part of its flight. It has to have something to do with the fact that the disc is spinning, but I've never seen or heard (or read) an explanation that I thought made sense.

Lithicon
06-13-2010, 09:03 PM
This actually makes me want to do a really dangerous experiment. To see how much spin a disc an really withstand before it'll physically pull it's self apart, and test to see just how non-moving spin affects the disc. The latter I can make a very educated guess at.

Elaborating on my post above, if you could some how make a machine to launch a disc in the air and spin at a given adjustable rate or RPM. Flat, true axis also, on a straight directional line. Starting with very low amounts of spin and accelerate it to upwards of 70MPH (most really far throwers will launch somewhere around 50-60mph). You'd see that as you increase the speed in the straight line, to keep the disc from wanting to change it's axis, you'd have to proportionately increase it's spin. It will only turn to the left once the disc just can't hold it's self in the air anymore.

Lithicon
06-13-2010, 09:07 PM
Actually, spin is part of what causes the disc to fade at the end of its flight. This is due to precession. The center of lift for a disc is in front of (relative to the direction of velocity) the center of rotation. This causes the disc to rotate nose up as it flies, and that rotation in turn causes the disc to want to fade (to the right for a RHBH throw) due to angular momentum. This effect is called precession.

I still don't understand why a disc turns to the right in the high speed part of its flight. It has to have something to do with the fact that the disc is spinning, but I've never seen or heard (or read) an explanation that I thought made sense.

That's only after spin and speed begin to slow down. The more spin it has close to the end of it's flight, as the speed is slowing down, the disc will still fade, but less dramatically. And, also as you mentioned the left turn being directly related to the nose up angle, because the disc is forced to slow down. The right turn is attributed some to nose down angle, as it allows the speed to be higher. From my understanding at least.

optidiscic
06-13-2010, 09:10 PM
to say that turn is related solely to DV is preposterous.....given this logic everything would turn to the right given enough speed. Planes, baseballs, rocks, bullets......this idea that spin does not affect turn is absolutely wrong..

bikinjack
06-13-2010, 09:17 PM
I could be wrong about this, but I'm of the opinion that spin (av) doesn't decrease nearly as much as forward speed (dv).

Also, if a disc's center of lift is closer to it's center of rotation, it will have less fade, because the torque applied would be smaller, causing less precession.

optidiscic
06-13-2010, 09:24 PM
I could be wrong about this, but I'm of the opinion that spin (av) doesn't decrease nearly as much as forward speed (dv).

Also, if a disc's center of lift is closer to it's center of rotation, it will have less fade, because the torque applied would be smaller, causing less precession.

I agree with this....I think straightness is more due to matching spinspeed with flightspeed like victorb said but that the key is for a disc to run it's length before the spin decreases

bikinjack
06-13-2010, 09:24 PM
OK, so here's question. What would happen if your could throw a disc perfectly flat with no spin, with the only force applied only in the direction of flight?

P.S. I think I already know the answer.

Technohic
06-13-2010, 09:26 PM
Ahh but to have spin not effect turn would have to assume a perfectly balanced distribution of weight. If you have a nick in the rim, wouldnt that effect what spin does? And, if you have it on a wobbly OAT plane, would that not have something to do with it.

Also, I remember a NASA physicist of some sort coming into my school and demonstrating to us that flight is not about the air under a plane but rather the flow over it, hence the rutter lifting to make the plane go up and then proceded to demonstrate lift by blowing air at a ball and clearly keeping it lifted by aiming it to go from the side and over the top. Sort of the propulsion of the plane moving forward keeping it in the air. I guess fast drivers with their sharper nose, nose down; would cause less air drag on the front and under the disc and more actually pushing the back-top of the disc and that is why speed would need to be maintained.


TBH, I have no idea what I am talking about or where it fits in here; I just wanted to be part of this thread, but I think maybe this is where the line of technique and physical aspects of the disc blur.

optidiscic
06-13-2010, 09:30 PM
so I will admit it I am ignorant about shapes of disc edges....I know drivers are sharper of course but are overstables shaped differently than understables?

sidewinder22
06-13-2010, 09:30 PM
Beads alter drag and lift making discs fly more stable. Similar to a race car in principle, spoilers make the car more stable to the ground.

optidiscic
06-13-2010, 09:35 PM
I am getting that beads simply reduce glide if they move air away from the underside of the disc?

Lithicon
06-13-2010, 09:39 PM
to say that turn is related solely to DV is preposterous.....given this logic everything would turn to the right given enough speed. Planes, baseballs, rocks, bullets......this idea that spin does not affect turn is absolutely wrong..
No, I meant that as a very generalized effect of the resulting experiment. As it has a lot to do with the disc's profile also.

I could be wrong about this, but I'm of the opinion that spin (av) doesn't decrease nearly as much as forward speed (dv).

Also, if a disc's center of lift is closer to it's center of rotation, it will have less fade, because the torque applied would be smaller, causing less precession.

I'd agree with this if I understand it correctly, seems to relate to exactly what I was said.

OK, so here's question. What would happen if your could throw a disc perfectly flat with no spin, with the only force applied only in the direction of flight?

P.S. I think I already know the answer.

The disc would flip upside down from the front, doing a back flip.

Scoot_er
06-13-2010, 09:41 PM
This thread is AMAZING!!!

What the heck are you trying to find out........as of Page 11?

VictorB
06-13-2010, 09:42 PM
I may be wrong, but I think that higher spin (AV) makes a disc more understable. That would mean that if you have 2 throws with the same disc at the same DV then the one with the higher AV would be more understable.

yes, you may be wrong.

sidewinder22
06-13-2010, 09:46 PM
I am getting that beads simply reduce glide if they move air away from the underside of the disc?

It goes both ways, adds lift/drag to the understable side, while decreases lift/drag to the other side.

VictorB
06-13-2010, 09:47 PM
I agree with this....I think straightness is more due to matching spinspeed with flightspeed like victorb said but that the key is for a disc to run it's length before the spin decreases


this is correct, and the value of the dv:av ratio for a true characteristic flight is different for every disc. that's why it makes it difficult to evaluate with values like high speed stability, low speed stability, glide, and speed. those are all subjective marketing terms.

Lithicon
06-13-2010, 09:47 PM
This thread is AMAZING!!!

What the heck are you trying to find out........as of Page 11?

I think he's wanting now to understand why specific wing profiles make each disc more or less stable, along with how beads affect this.

Scoot_er
06-13-2010, 09:54 PM
I think he's wanting now to understand why specific wing profiles make each disc more or less stable, along with how beads affect this.

I will get Dave Mac on this board and you will have more info then you want!

When it comes down to playing good rounds.........a beaded disc is almost always more reliable then a non-beaded counterpart.

A Teebird is better into a wind than an early Star Destroyers (pre S/DS)

This is because a disc with a bead has a higher resistance by its frisbee instinct....even if it may not be as overstable as another non-beaded mold. Basically it has a higher "boiling point" before it tries to turn......this is why some Xcals will flip in a decent headwind leaving the thrower wondering what happened to his normally overstable disc.

Game is on be back later.

Lithicon
06-13-2010, 09:56 PM
Victor, by the way you're explaining the spin increased equally to the amount of speed will stabilize it, I agree here.

If the spin is reduced and the speed remains the same, the disc will act less table, correct? The amount determined a lot by the physical characteristics of the disc.

Then as the disc loses speed and spin both, it will fade.

Also, as pertaining to "over stable" disc even they could be turned with correct amounts of speed vs spin ratios. And, the fade of any disc is prolonged with the amount of spin left as the speed of the disc is running out.

Is this correct?

NateDiscFlip
06-13-2010, 10:00 PM
This thread is pretty good once you skip Nate's posts. this is a good discussion going on.



I didn't know this. I am going to have to check this out. Putting beads on discs kinda seems counter-intuitive to this though.

STALKER franky...that's all you need to know:popcorn:

Olorin
06-13-2010, 10:07 PM
I may be wrong, but I think that higher spin (AV) makes a disc more understable. yes, you may be wrong.
Well, you may be right, but can you prove it with a reference to any outside source? I don't mean any offense, but there's just so much misinformation on the internet that I'd prefer to see it backed up from a reliable source. I've studied Potts and Hummel's articles pretty closely to come to the conclusion I stated.

Here are some of my notes from the Physics (http://www.dgcoursereview.com/forums/showthread.php?p=377700#post377700) thread:

Factors that increase the right turn of a disc:
1.Higher spin rate
2.Narrower rim
3.Nose down. Below 9 degrees Angle of Attack (AoA) contributes to a right turn by precession
4.Being beat in
4. Headwind
5. Lighter weight of the same mold, same disc
6. Lower density plastic
7. Higher dome
8. Air temperature.

Oh, and here's a list of some of the resources I used that one can consult for further research: Aerodynamics of Flying discs (http://sites.google.com/site/dgresources2/Home/aerodynamics/aero-resources)

BrotherDave
06-13-2010, 11:17 PM
http://theinvisibleagent.files.wordpress.com/2008/12/transit.jpg?w=453&h=600


Here, Frank D. is seen working diligently in his office. "Being surrounded by balls helps me think," he says. Sure they do Frank, you crazy rascal.

http://theinvisibleagent.files.wordpress.com/2008/12/earths2.jpg?w=460&h=563

Frank Delicious
06-13-2010, 11:21 PM
So shiny.

Lithicon
06-13-2010, 11:58 PM
Oh you pranksters, you.

optidiscic
06-14-2010, 06:08 AM
What causes turn in a disc RHBH throw
1.Higher spin rate-causes disc to have more lift on the L side-thick rims are tough to make spin fast
2.Narrower rim-obviously a narrow rim is easier to spin
3.Nose down. Below 9 degrees Angle of Attack (AoA) contributes to a right turn by precession-technique irrelevent to thread
4.Being beat in-lowers the flightspeed/spinspeed characteristics of a disc to make it reach its flight characteristics-a beat in groove at spped 13 will perform more like a speed 9 valkyrie once beat in
4. Headwind-essentially speeds up the air speed over the disc causing L side lift to occur sooner
5. Lighter weight of the same mold, same disc-can be thrown faster/more spin and is more prone to L side lift and thus turn
6. Lower density plastic-air molecules affect the disc more than on harder plastics and thus more L side lift
7. Higher dome-again more glide and thus more L side turn
8. Air temperature.-would cause air molecules to expand and air density would increase thus the disc would be cutting through thicker air causing more lift and thus turn

I would add elevation and humidity as both also cause dramatic effects on air density and thus changes in stability of discs is experienced
Tailwinds slow a disc down and actually add stability and lower turn as lift is decreased

The easiest disc to turn would be a low weight, slower speed, beat in low grade plastic, narrow rimmed, domey disc thrown with anny on a hot humid day at or below sea level into a stiff wind at full snap by a top distance pro......Think Avery Jenkins throwing a 144g 10 yr old dx stingray into a hurricane wind on Miami Beach in August on an anhyzer line

optidiscic
06-14-2010, 06:19 AM
Discoveries this thread has given me
-beads and wing shape alter stability by either reducing glide or causing weight shifts that affect stability--still a bit hazy but this seems to make sense
-harder plastics not only last longer but are essentially faster and straighter flying plastics
-Jury is still out on turn (understability) but I am in the lift differential theory as it explains turn and fade as it is related to spin. Rim width and disc weights etc. all affect spin and turn.
-thicker rims not only usually reduce spin which negates turn the thick rims reduce surface area under a disc and thus reduce glide

-there are some really cool guys on DGCR who know a bit about discs not named threeputt...still anxiously awaiting his take on all of this

Olorin
06-14-2010, 06:50 AM
Angular velocity [av] (spin imparted on a disc at release)
Directional velocity [dv] is the forward speed of a disc.
If the dv:av ratio is very high, the disc will act understable.
1) I'm not convinced that a ratio of DV to AV is a correct explanation of disc flight.

Potts gives a formula for Spin parameter that Hummel quotes (p. 8)
Spin parameter is the ratio of the velocity of the outer edge due to spin to that due to translation
S = rωz/v (Potts 2.4)
where r is the radius, ωz is the spin angular velocity, and v is velocity.

But I need to refresh my understanding of how Potts uses this spin parameter.

2) According to this ratio with a constant AV merely increasing the DV increases understability. I've never read anything that indicates that the DV has a direct effect on whether a disc will fly understable or overstable. Would you please provide some references that show this?

3) According to the explanation of this ratio then the AV has an inverse effect on understability. That is, if you increase AV then you decrease understability. If you decrease AV then you increase understability. This is the opposite of my research, but I'd have to dig around to prove this with references. Here's one, though:
“Increasing the spin can surely make a disc turnover more.” Dave McCormack of Gateway (turnover for RHBH = more understable)

optidiscic
06-14-2010, 07:12 AM
Another one that I've hard is that the different colors a disc is made in affects flight as well. Not sure if these just signify particular runs or if the dyes used affect things somehow....might be a hippy fairytale for all I know. I just have heard it mentioned more than once from different people on the course.

optidiscic
06-14-2010, 07:18 AM
What exactly happens from run to run that changes disc features and thus flight characteristics?

trifocal
06-14-2010, 08:13 AM
What exactly happens from run to run that changes disc features and thus flight characteristics?

Interesting thread....I'll take a stab at this question.

1. A slight change in the plastic formula. Different materials, different ratios of ingredients. Dyes? Do different colored dyes affect how the plastic sets in the mold?

2. Wear on/or degregation of the mold.


I think it might be cool to see some kind of 3d interpretation (view) of say a Tee_Bird thrown flat at say 50mph with 3 different spin rates. Then, 55 mph with 3 diffrent spin rates. Etc. In other words, run trials of one disc at varying speeds and spin rates. I'd like to see 2 views of this experiment...one from ground level that shows elevation (lift) changes and one view from above that shows the flight path and where turn and fade begin/end relative to distance from the tee.

Technohic
06-14-2010, 08:16 AM
What exactly happens from run to run that changes disc features and thus flight characteristics?

PLH is different which Marmoset had a thread fairly detailed on the subject. Let me see if I can find it.

EDIT: Here it is.

http://www.dgcoursereview.com/forums/showthread.php?t=13889&highlight=PLH

VictorB
06-14-2010, 08:25 AM
1) I'm not convinced that a ratio of DV to AV is a correct explanation of disc flight.

Potts gives a formula for Spin parameter that Hummel quotes (p. 8)
Spin parameter is the ratio of the velocity of the outer edge due to spin to that due to translation
S = rωz/v (Potts 2.4)
where r is the radius, ω is the angular velocity, z is a constant, and v is linear velocity

But I need to refresh my understanding of how Potts uses this spin parameter.

2) According to this ratio with a constant AV merely increasing the DV increases understability. I've never read anything that indicates that the DV has a direct effect on whether a disc will fly understable or overstable. Would you please provide some references that show this?

3) According to the explanation of this ratio then the AV has an inverse effect on understability. That is, if you increase AV then you decrease understability. If you decrease AV then you increase understability. This is the opposite of my research, but I'd have to dig around to prove this with references. Here's one, though:
“Increasing the spin can surely make a disc turnover more.” Dave McCormack of Gateway (turnover for RHBH = more understable)

1) While the explanation that I gave might not be mathematically correct, it is theoretically sound. (I'd have to get JHern in here to explain mathematically how it works, I only have a bachelor's in physics) Just looking at the formula, I'd guess that z is a constant of some sort - most likely related to moment of inertia, which is related to the proportioning of the weight through the flight plate and wing. As the weight is distributed more on the outer edge of the disc, the moment of inertia increases, therefore increasing the force needed to reach a specific angular velocity. The centrifugal force of the disc is what keeps it holding a certain plane of inflection. The higher the amount of centrifugal force (which is directly related to the angular velocity imparted on the disc) the more resistant the disc will be to change it's angle of inflection...but we all know that the disc is constantly losing angular velocity through it's flight, so as the disc slows it's rotation, the centrifugal force cannot hold the weight of the disc on a specific plane, and the disc fades and falls off in its flight.

2) The best way to field test this is throw sidearm vs backhand with the same disc, trying to throw it the same distance. Backhand naturally produces more spin on the disc than sidearm does. This is the reason why sidearm throwers prefer more overstable flying discs.

3) I wouldn't trust Dave when it comes to disc flight physics (remember the speed demon dt, and how it was supposed to be understable?). He's pretty much strictly a businessman. I'd listen to him about plastic blends and molding though.

VictorB
06-14-2010, 08:28 AM
Interesting thread....I'll take a stab at this question.

1. A slight change in the plastic formula. Different materials, different ratios of ingredients. Dyes? Do different colored dyes affect how the plastic sets in the mold?

2. Wear on/or degregation of the mold.


I would say that #1 has little to no overall affect on how a disc flies. The coefficient of friction between similar plastics isn't great enough when traveling through air - at least at the speeds that we can throw discs at - to make any noticeable difference in flight.

#2 does cause a difference in flight characteristic, but that is more due to multiple impacts causing the wing of the disc to be pulled down, creating more lift (mimics a 'higher dome' and causes air pressure differences across the dome to be greater than what was intended for the disc).

mashnut
06-14-2010, 08:35 AM
On #1, different plastics cool differently and shrink different amounts, so a change can certainly make a difference in flight characteristics, look at the big differences between flights of the same mold in different plastics (e.g. dx teebird vs. champ teebird, totally different disc).

#2 I think he was talking about the mold pieces that form the disc, not the disc itself degrading.

optidiscic
06-14-2010, 08:48 AM
2) The best way to field test this is throw sidearm vs backhand with the same disc, trying to throw it the same distance. Backhand naturally produces more spin on the disc than sidearm does. This is the reason why sidearm throwers prefer more overstable flying discs.
Did you mean sidearm creates more snap and spin? This would explain why a sidearm/overhand throw does better with more stable plastic....a more stable disc can handle more snap/spin.

Again I always thought sidearmers preferred shallow rim but more stable discs as they can be snapped hard but remain stable.... not many like to flick bulky thick rimmed drivers from what I've seen.

Backhand generates greater DV but less AV to use your terms....I hope I have this right.

Olorin
06-14-2010, 08:50 AM
Potts gives a formula for Spin parameter that Hummel quotes (p. 8)
Spin parameter is the ratio of the velocity of the outer edge due to spin to that due to translation
S = rωz/v (Potts 2.4)
where r is the radius, ωz is the spin angular velocity, and v is velocity.
Note: this is the correct version. The "ω" is the Greek letter omega that represents spin rate, and "z" is a subscript that doesn't format correctly here. "z" is not a constant, but it denotes the spin rate about the Z axis.


S = rωz/v (Potts 2.4)
where r is the radius, ω is the angular velocity, z is a constant, and v is linear velocity
For the record, this change that VictorB made is incorrect. "z" is not a constant, but it is explained above. I hope that this change doesn't get copied and repeated.

trifocal
06-14-2010, 08:53 AM
On #1, different plastics cool differently and shrink different amounts, so a change can certainly make a difference in flight characteristics, look at the big differences between flights of the same mold in different plastics (e.g. dx teebird vs. champ teebird, totally different disc).

#2 I think he was talking about the mold pieces that form the disc, not the disc itself degrading.

Yes.(#2) thats what I was getting at....over time and use a mold (it seems to me) has to change shape in some fashion. How this affects the performance of the disc seems to fall into that shady area that scientists humbly muse...."not clearly understood."

Olorin
06-14-2010, 08:56 AM
Backhand naturally produces more spin on the disc than sidearm does. This is the reason why sidearm throwers prefer more overstable flying discs.

Did you mean sidearm creates more snap and spin? This would explain why a sidearm/overhand throw does better with more stable plastic....a more stable disc can handle more snap/spin.Opti,
I think you're right. My understanding is that a forehand creates more spin, not less. Garubladder? Treeput?

sidewinding
06-14-2010, 09:01 AM
Forehand creates less spin.

optidiscic
06-14-2010, 09:07 AM
Something to consider regarding turn and understability

Longer discs (faster discs) to me are those that begin their turn later in their flight..

Consider an Eagle and an Orc.....both employ the same glide, turn, and fade but the Orc is a speed 10 disc and the Eagle is a speed 7 disc. If I throw both discs flat at speed 10 then the Eagle will turn and fade prematurely while the Orc will turn later and fade later and produce a longer flight. If I throw both discs flat at speed 7 the Orc will not turn as much and will subsequently have a more pronounced fade than the Eagle.....distance may be comprable but this is more due to the Orc cutting through the air due to it's speed than the flight characteristics.

Why is this so-because the difference in lift of the R and L sides of the disc generated by spin. The flightspeed air movement is constant...what causes a disc to eventually flip and turn in flight and not out of the hand is the miniscule amounts of lift differential caused by every revolution of the disc....the more spin that is produced the sooner a disc will Lift lopsidedand turn...(Eagle) a thicker rimmed disc will be resistant to this spinning but if powered enough will eventually lopsided lift and turn only later in it's flight (ORC) This is why only true power arms can throw the higher speed discs properly.

optidiscic
06-14-2010, 09:11 AM
Forehand creates less spin.

Thanks the more I think about this it makes sense as you are getting far more wrist movement out of a backhand technique than the shorter forehand wrist motion...So Forehand throwers rely more on flightspeed than spinspeed?

I am not really sure about this though....seems to be contrary to what I have seen.

VictorB
06-14-2010, 09:11 AM
2) The best way to field test this is throw sidearm vs backhand with the same disc, trying to throw it the same distance. Backhand naturally produces more spin on the disc than sidearm does. This is the reason why sidearm throwers prefer more overstable flying discs.
Did you mean sidearm creates more snap and spin? This would explain why a sidearm/overhand throw does better with more stable plastic....a more stable disc can handle more snap/spin.

Again I always thought sidearmers preferred shallow rim but more stable discs as they can be snapped hard but remain stable.... not many like to flick bulky thick rimmed drivers from what I've seen.

Backhand generates greater DV but less AV to use your terms....I hope I have this right.

You have it backwards. Really terms like 'snap' should be left out of it, since snap really doesn't have a definition.

Sidearm produces more linear velocity, while at the same time producing less angular velocity. Throwing discs sidearm tends to make them act less stable.

Backhand throws produce more angular velocity, but less linear velocity than sidearm. Discs tend to act truer to their flight characteristics this way.

VictorB
06-14-2010, 09:19 AM
Note: this is the correct version. The "ω" is the Greek letter omega that represents spin rate, and "z" is a subscript that doesn't format correctly here. "z" is not a constant, but it denotes the spin rate about the Z axis.


That makes more sense. Here's a little more description of angular velocity. (for those that want to read it)


In physics, the angular velocity is a vector quantity (more precisely, a pseudovector) which specifies the angular speed of an object and the axis about which the object is rotating. The SI unit of angular velocity is radians per second, although it may be measured in other units such as degrees per second, revolutions per second, degrees per hour, etc. When measured in cycles or rotations per unit time (e.g. revolutions per minute), it is often called the rotational velocity and its magnitude the rotational speed. Angular velocity is usually represented by the symbol omega (Ω or ω). The direction of the angular velocity vector is perpendicular to the plane of rotation, in a direction which is usually specified by the right hand grip rule.[1]

optidiscic
06-14-2010, 09:21 AM
Regarding forehand...would it be safe to say that shallow rim but stabler discs are popular as it is easier to produce spin while also maintaining stability?

VictorB
06-14-2010, 09:27 AM
Regarding forehand...would it be safe to say that shallow rim but stabler discs are popular as it is easier to produce spin while also maintaining stability?

It would be more correct to say that more overstable discs mask the forehand throwers inability to generate proper spin on a disc.

Shallow or deep rim is subjective to what's comfortable to the thrower.

optidiscic
06-14-2010, 09:30 AM
Regarding plastics cooling.....the faster a plastic cools the harder it will be? and do certain colors cause the plastics to cool at different rates?

garublador
06-14-2010, 09:31 AM
Opti,
I think you're right. My understanding is that a forehand creates more spin, not less. Garubladder? Treeput?I don't know. I don't know of an instance where it's been measured. My best guess is that forehand shots tend to turn over more because people have more OAT in their forehand throws.

IMO, this is the most important quote of the thread so far:

Finally, be careful of material you see on the forums, much of it contains significant conceptual errors, and as the discussion evolves some of the information could easily be taken out of context.

optidiscic
06-14-2010, 09:33 AM
It would be more correct to say that more overstable discs mask the forehand throwers inability to generate proper spin on a disc.

Shallow or deep rim is subjective to what's comfortable to the thrower.

according to what you are saying more stable discs are easier to spin or are you saying something else..I'm either lost or don't agree.

sidewinder22
06-14-2010, 10:24 AM
It would be more correct to say that more overstable discs mask the forehand throwers inability to generate proper spin on a disc.

Shallow or deep rim is subjective to what's comfortable to the thrower.

I agree. Typically a disc thrown the same distance FH or BH, will have more spin BH, but it really depends on how they are thrown. BH has more spin potential. FH is easier to get leverage on, as well as oat.

I think opti is confusing shallow with narrow. Shallow means how deep or high the rim. Narrow refers to rim width. I agree with narrow overstable discs being easier to spin.

grodney
06-14-2010, 11:15 AM
Not that my chiming in matters, but:
- More spin does NOT make a RHBH turn over more.
- For MOST (almost all) throwers, FH produces a higher speed:spin ratio. That is, more speed FH, more spin BH.
- Both of these points are VERY commonly reversed among players, and have been that way for years and years.

grodney
06-14-2010, 11:41 AM
VictorB, a question for you.

You know those marketing terms that Innova has: Speed, Turn, Fade, Glide? Let's talk about "Turn" and "Fade".

Given two discs, is it possible for one to BOTH "Turn" more, and "Fade" more? With the important assumption that everything else between the discs is equal (speed, spin, angle, etc.).

If so, what physical characteristics could/would cause such a difference?

optidiscic
06-14-2010, 11:42 AM
I refuse to believe that speed of the disc and notspin is responsible for high speed turn. If you take the spin factor out then you are left with solely flightspeed of the disc. I would like someone in this camp to explain these to me in a way we can all understand.
-longer flying discs perform their turn later in the flight when the disc is actually traveling slower than when initially thrown.
-air would move at the same rate past a disc if there was no spin....how would the anhyzer angle be achieved if there is no difference in air pressures/lift?
-According to your speed theory an airplane would turn to the right as would any object moving at high velocity.

I think the misconception is that a tight fast spinning throw will enable a disc to fight fade and appear to be going straighter....perhaps these throws are employing a very stable disc or the thrower is employing some OAT. (hyzer release)

optidiscic
06-14-2010, 11:43 AM
I agree. Typically a disc thrown the same distance FH or BH, will have more spin BH, but it really depends on how they are thrown. BH has more spin potential. FH is easier to get leverage on, as well as oat.

I think opti is confusing shallow with narrow. Shallow means how deep or high the rim. Narrow refers to rim width. I agree with narrow overstable discs being easier to spin.

yeah I meant narrow rim:doh:

Olorin
06-14-2010, 12:03 PM
Not that my chiming in matters, but:
- More spin does NOT make a RHBH turn over more.
- For MOST (almost all) throwers, FH produces a higher speed:spin ratio. That is, more speed FH, more spin BH.
- Both of these points are VERY commonly reversed among players, and have been that way for years and years.
Rodney,

I'm glad you chimed in. I respect your knowledge and experience. Now I don't know what's correct. I'm not saying you're wrong, but can you cite any external evidence to support the claims of your first 2 points? And with all due respect how can I know that you aren't the one who has gotten the points reversed? As for me, I'm rather befuddled about these points at the moment.

I'm not debating; I'm only trying to get at the truth. Garublender made the best point that this is the internet and there's tons of misinformation in forums, so I just like to see claims backed up with something more factual than mere statements. e.g.- If you could point to a Wikipedia article that would definitely prove your point. ;)

optidiscic
06-14-2010, 12:27 PM
I'm still waiting for something that makes sense but all I'm getting is jargon in regards to why spin does not affect turn.

I would like to hear more about these:
the bead
the beveled edge
the groove on the groove and monarch
gimicks on more obscure discs
colors and why different runs perform differently (ive heaerd tie dye champion is by far the hardest and fastest)
why do some flat tops perform so stable...zone?

VictorB
06-14-2010, 12:30 PM
I'm still waiting for something that makes sense but all I'm getting is jargon in regards to why spin does not affect turn.

I would like to hear more about these:
the bead
the beveled edge
the groove on the groove and monarch
gimicks on more obscure discs
colors and why different runs perform differently (ive heaerd tie dye champion is by far the hardest and fastest)
why do some flat tops perform so stable...zone?

I think I've explained about as much as I can without getting too in depth here.

I'll reference you back over to one of the other disc physics threads, either here or the one on DGR.

Lithicon
06-14-2010, 01:11 PM
I'm still waiting for something that makes sense but all I'm getting is jargon in regards to why spin does not affect turn.

When you ask on a forum about physics of flight you're going to get physics jargon. Unless you're wanting a mathematical lay out of why each disc varies in flight. If you are, I highly doubt anyone here will break it down that far, so I don't know what else you could really want, these relative explanations/jargon is all there is to give.

optidiscic
06-14-2010, 02:28 PM
My point wasn't about jargon. My point was to move away from the turn spin debate Poor choice of words wasn't trying to incite.

Lithicon
06-14-2010, 03:10 PM
Angular velocity [av] (spin imparted on a disc at release) is the what keeps a disc "holding a line" - whether that be hyzer, straight, or turnover. Moment of inertia [mi] determines the force that is needed to get a disc spinning.

Directional velocity [dv] is the forward speed of a disc. Each disc requires a certain directional velocity to fly properly. If the dv:av ratio is very high, the disc will act understable. if the dv:av ratio is low, the disc will act more overstable than it really is.

Lift is the force generated by air passing faster over the flight plate when compared to the under side of the disc. The differences in air speed passing the disc cause a slight difference in air pressure - with the higher pressures being applied to the underside of the disc - creating a slight upward force that works against gravity. This is also known (somewhat incorrectly) as glide.

Stability is a rating based on the ability for a disc to keep it's center of pressure (where the lift force is applied to the disc) close to the true center of the flight plate. Overstable discs tend to have a center of pressure on the on the right side that the disc, thus the disc wants to lift it's wing on the right side (RHBH throwers). The opposite is true for understable discs, but given enough time in the air, the center of pressure will move back to the right side of the disc, causing the right wing to lift. (see JHern's thread on dgr for an illustrative reference) Stable discs tend to balance the center of pressure better than the other two categories, and therefore fly on truer lines than the other two.

Opti,
I think you're right. My understanding is that a forehand creates more spin, not less. Garubladder? Treeput?
From my understanding, Forehand does have a higher POTENTIAL for leverage on the disc, but is often over shadowed by the inability of most players to create the proper leverage to create spin, thus most strong arm creating more speed. Put that in physic's speak, and you have less AV/more DV.
Not to mention as Garu explained, the OAT potential is much greater in Forehand throwers, so it's a bit hard to use this as some definitive proof. Take this case below, what I said above is essentially what he said.

Not that my chiming in matters, but:
- More spin does NOT make a RHBH turn over more.
- For MOST (almost all) throwers, FH produces a higher speed:spin ratio. That is, more speed FH, more spin BH.
- Both of these points are VERY commonly reversed among players, and have been that way for years and years.

Now, according to Victor's description I've put on what I'll consider one of the most inconclusive experiments you could attempt, lol. I'm not by any means sharing this as indisputable proof, to argue, or to prove anything. JUST FOR MERE OBSERVATIONS, which were highly inconclusive.

I took three disc, semi over to stable DX, over stable Champion, and an under stable DX. The actual mold isn't important, but trust me when I say they're what they say they are.
I balanced them best I could on a needle point, so that it could float on whichever axis it chose once it began moving. But, I started them spinning and made sure they were as close to the true flat axis as I could.
(Just to note, I had no way of measuring th RPM, so no I don't know any were at a constant, or same rpm through this. So just adds to the inconclusiveness.)
Then I applied air pressure to the front of all three disc equally and directly across the front (nose) of the disc, all three tried to great lift and went a nose down and came off the needle point.
Then as if the disc was flying toward me, I applied air pressure to the left and right side as equally as possible.

With ALL THREE disc as if flying toward me, (applying air pressure away from me toward the disc)
Applying air to the right side of the disc, the nose would go down, and the disc would lean to the left. (overstable) RHBH
Applying air to the left side of the disc, the nose would go down and the disc would lean to the right. (Understable) RHBH

I Personally done this for ****s and giggles, but my opinion on the way stability is affected..

(Would like to note this is also rather vague, and of course lacks some sort of mathematical details as I'm sure that would be hard for even scientist to measure ratio's needed for said desired effects listed below.)

The way victor describes it vaguely(and is by no means a bad thing) but, he describes AV(spin), and DV(speed). Spin and speed, when spin is kept constant, and speed is kept constant (at a given ratio) The disc will fly true and "stable". Given a proper AOA, (angle of attack) which I'm concluding to some degree of nose down, but that's relative to height as far as I can conclude.
Now, with the same Aoa, and the same DV as the first example, but less AV, the disc will act less stable, and tilt to the right, RHBH. This creates less air pressure on the right side of the disc, making the disc pull to the area with less air pressure. Thus turning the disc right.

Same, Aoa, less DV, but the same AV as the first the disc will remain stable on it's given axis, due to the AV. Until the av begins to slow down with the DV, the disc will change slightly in it's Aoa, and the disc is then forced to slow further creating less air pressure on the left side, pulling the disc to the left.

Now, this all happens because the disc is spinning though.
Optic gives an example of an airplane accelerated at a certain speed would try to turn right, but no. A disc with no spin accelerated will create lift like an airplane would and go up. The spin creates the "magnus effect" created by spinning objects, the air pressure changes, which causes a directional shift other than just simply up. Essentially one part of the wing is trying to go up, but is countered by the fact it's spinning. So when one goes up, the other has to go down. Airplanes would not be affected by this, as it's wing isn't spinning, thus creating a total lift, upwards. (By this effect if you were able to alter the air pressures around a bullet controllably, you'd be able to better control a bullet. Which if I'm not mistaken is being tested.)

Now, Aoa seems to be very key in this, seems to be slightly over looked as I believe it plays just a big of a role as DV, and AV. Aoa will make a disc either slow down, (nose up) or speed up(nose down). It also changes how the air flows across the disc affecting how key features work, creating lift, creating air pressure differences, and ultimately affecting the stability of the disc. As most of us know from throwing nose up for years. :p

To touch on something that's been left out of the discussion is the reverse COG (center of gravity) disc exhibit. I'm sure this has something to do with the air pressures and how spin and speed effect them. This I don't know, but It's apparent in the physical features of disc. So therefore, I'd make an educated guess that it's affects plays a good sized role the stability too.

So, the magnus effect, coupled with Aoa, and DV, and AV, AND the COG of the disc are what give you turn. I say it's a big mix of all of these, and not just one, as there are too many variables in the flight that can be a cause of stability. HOW exactly those affect the flights I think my descriptions above based off Vctor's and others descriptions are pretty sound theoretically. Any disc given the proper ratio's would displays all of these characteristics of flight. Just the ratio's would be different for different molds. This is my take on it.

sidewinder22
06-14-2010, 03:32 PM
I refuse to believe that speed of the disc and notspin is responsible for high speed turn. If you take the spin factor out then you are left with solely flightspeed of the disc. I would like someone in this camp to explain these to me in a way we can all understand.
-longer flying discs perform their turn later in the flight when the disc is actually traveling slower than when initially thrown.
-air would move at the same rate past a disc if there was no spin....how would the anhyzer angle be achieved if there is no difference in air pressures/lift?
-According to your speed theory an airplane would turn to the right as would any object moving at high velocity.

I think the misconception is that a tight fast spinning throw will enable a disc to fight fade and appear to be going straighter....perhaps these throws are employing a very stable disc or the thrower is employing some OAT. (hyzer release)

Basically if you only spin a disc it will stay fairly stationary until it loses spin. If you throw a disc without spin it will flip upside down. Its a combination of spin and speed that make a disc turn but typically more speed dependent.

The later turn is from hyzer-flipping, they can look flat and straight, but they are turning the entire flight(they can't all the sudden turn right) and hit the ground before they run out of spin and begin the fade. So they are shorter hyzer-flips.

The physics are different between a disc and an airplane wing because of spin and wing design. A flying spinning disc alters lift/drag from left to right side. An airplane wing only alters lift/drag front to back.

Lithicon
06-14-2010, 03:49 PM
My point wasn't about jargon. My point was to move away from the turn spin debate Poor choice of words wasn't trying to incite.

Ahh, understood. I was thinking about the dye. And, the only way I can come to understand this is the way it molds up during the cooling process due to the color of dyes used. I honestly can't see any other way to explain it. It's obvious color will either accept, dissipate heat at different rates. But, some have said this doesn't affect the disc that much, but if one is cooling slower than the other, I could see gravity possibly having some affect on it more sitting around while it's cooling. I don't know, just my guess.

The plastic thing I sort of gave my opinion, but Victor says the plastics aren't affected that much by the speeds at which we throw them. I'm not sure if I completely agree there, because aerodynamics have as much, or a very slight bit more effect on slower moving objects. I'm not sure if this translates in the air, but it does on the ground. As far as creating down pressure and for Nascar, this all works on the same principles for dirt race cars that aren't moving nearly as fast.

Ryan P.
06-14-2010, 03:53 PM
This could be a book. It'd be a conversation driven, book, with the comedic relief provided by everyone knows who.

optidiscic
06-14-2010, 04:20 PM
Faster cooling rates would not allow molecules to disperse as fast so the faster cooled plastics would end up being harder plastics and harder plastics are faster plastics....(leaps in logic I know) So I would guess that any abundance of dye would cause cooling to slow down? Maybe clearer plastics are harder as these have less dye? Perhaps certain discs contain more dyes or different dyes affect cooling rates in different ways.....thats where I'm going with the whole color affects disc flight ideas floating out there...pure conjecture.

jrawk
06-14-2010, 05:45 PM
I'm still waiting for something that makes sense but all I'm getting is jargon in regards to why spin does not affect turn.

I would like to hear more about these:
the bead
the beveled edge
the groove on the groove and monarch
gimicks on more obscure discs
colors and why different runs perform differently (ive heaerd tie dye champion is by far the hardest and fastest)
why do some flat tops perform so stable...zone?

I tried to get caught up on this thread as best/fast as possible.

Pardon if this has already been said. Adding a bead to the bottom of the rim is like adding a 'spoiler' to a race car.. or another analogy is moving the elevator down on an airplanes tail wing. The taller the bead, the more prone the disc will be fading toward the ground. This, I assume, is the easiest way to counteract a discs understability. Shave the bead off a Roc and it will behave similar to a Buzzz. Or.... shave the bead off a Wasp and it will be similar to a buzzz.

volklgirl
06-14-2010, 06:19 PM
Dang, this thread really makes me feel like the ditzy blond I am. :confused: I need to go back to college just to read this and have it make sense. :(

Great discussion guys!!!:thmbup:

optidiscic
06-14-2010, 09:32 PM
Dang, this thread really makes me feel like the ditzy blond I am. :confused: I need to go back to college just to read this and have it make sense. :(

Great discussion guys!!!:thmbup:

no worries volk we are just a bunch of guys pretending to be smart online:)

sidewinder22
06-14-2010, 09:54 PM
I tried to get caught up on this thread as best/fast as possible.

Pardon if this has already been said. Adding a bead to the bottom of the rim is like adding a 'spoiler' to a race car.. or another analogy is moving the elevator down on an airplanes tail wing. The taller the bead, the more prone the disc will be fading toward the ground. This, I assume, is the easiest way to counteract a discs understability. Shave the bead off a Roc and it will behave similar to a Buzzz. Or.... shave the bead off a Wasp and it will be similar to a buzzz.

Post #105. Good examples though. :thmbup:

tstack10
06-15-2010, 12:57 AM
You guys know a lot

garublador
06-15-2010, 09:44 AM
I refuse to believe that speed of the disc and notspin is responsible for high speed turn. If you take the spin factor out then you are left with solely flightspeed of the disc. I would like someone in this camp to explain these to me in a way we can all understand.You need both a rotational direction (direction of spin) and a linear direction (direction of flight) to define which way a disc will turn and fade. Both of them obviously contribute to both turn and fade.

Think about how freestyle players throw their discs. They take pretty understable discs (lids), spin the crap out of them but put very speed on them. The discs don't flip. In fact, they tend to hold the angle they're on really well, which is why they do it that way.

Its a combination of spin and speed that make a disc turn but typically more speed dependent.That's my understanding, too. There's no doubt that spin helps increase resistance to turn and fade, but how much angular momentum (something I understand) a disc has compared to the areodynamic forces (something I do not understand) is something that I can only guess on based on my experience with disc flight.

More "snap" tends to give a disc both more speed and more spin. The ratio of spin to speed appears to be different on a high snap throw than a low snap throw.

Here's my take on it based on what I've observed and read. On a high snap, hyzer flip throw with a fairway driver (Teebird maybe) a disc starts off way above its cruise speed (which is determined by rim configuration and spin) and quickly starts flipping. As the disc rapidly slows down, the rate of flip also rapidly slows down. This is why discs appear to "snap" up from a hyzer on high snap throws rather than slowly flipping up from a hyzer on lower snap throws.

This part is even more of a guess: then, late in the flight the disc will turn a bit. At this point the disc's spin is slowing down fast enough compared to the speed to where the angluar momentum of the disc can't offset the aerodynamic forces anymore so the disc flips. Not long after that the speed slows down to the point where the disc gets to the fade part of the flight and the disc fades forward or forward/left.

On a lower snap throw, the spin to speed ratio is different so the disc slowly flips up, doesn't hold the line as "strong," never gets the late turn and the disc fades harder left. The disc doesn't slow down to its cruise speed as fast, maybe because the difference in disc speed to cruise speed isn't as high, and the disc isn't in the air long enough to get that late turn. By the time it would get that late turn the disc is slow enough to fade instead.

Again, those are the theories of a non aerodynamics guy based on what I've observed of disc flight and the little I've absorbed from threads like this.

optidiscic
06-15-2010, 10:03 AM
Nice stab Garu I agree with you....those who simply say snap does nothing to create turn will have a difficult time explaining the hyzer flip....according to their logic the hyzer flip throw should just hold the hyzer line. The problem is as you have stated that spin and speed are usually achieved at the same time in the same ratios. When a freestyler spins a disc you are forgetting that there is little air moving over them from one direction...the air moving faster over a disc (speed) combined with spin (rotations) is what causes the change in lift on either side of a disc.
Speed simply gets a disc out further away from the tee faster before the turn begins. I would guess that turn actually happens in roughly the same time lapse in short and long throws.

garublador
06-15-2010, 11:44 AM
The problem is as you have stated that spin and speed are usually achieved at the same time in the same ratios. If I said that I didn't mean to. I don't know if they are acheieved with the same ratios or not.

When a freestyler spins a disc you are forgetting that there is little air moving over them from one direction...the air moving faster over a disc (speed) combined with spin (rotations) is what causes the change in lift on either side of a disc.But if it's only spin that causes turn, then how come the disc isn't turning? How will it "know" which direction to turn without any sort of linear movement? There is no "right" or "left" without that speed vector. That means it's obvious that speed not only causes turn, it's required for "turn" to even mean anything.

Speed simply gets a disc out further away from the tee faster before the turn begins. I would guess that turn actually happens in roughly the same time lapse in short and long throws.Speed/nose down causes turn. There's no doubt about that. Without speed a disc will not turn as illustrated with the freestyle type throw. You need a relative air speed to get turn and more relative air speed means more turn.

optidiscic
06-15-2010, 12:06 PM
Speed and spin are required. They work together. But it's the speed of air moving over the disc which is really important. Speed and spin both contribute to this. Speed and Spin need to work together to create turn. The ratio I meant typically a harder throw will create more spin and a slower throw will create less spin. So the two r intrinsically linked typically.

NateDiscFlip
06-15-2010, 12:15 PM
Post #105. Good examples though. :thmbup:

Not sure, since a buzzz seems more overstable than a roc

as for a stalker, without the ring is probably like a tracker....

I guess I always thought the ring was for stability, as a wasp is slower than a buzzz....or something...

hard to say....throw STALKERS!!!

Lithicon
06-15-2010, 12:45 PM
Heh, that's the way to do it.

Just wondering, if anyone read my post on the last page. It was long, but like I said in it. I think there are a lot of variables together that alter stability.

sidewinder22
06-15-2010, 04:04 PM
Not sure, since a buzzz seems more overstable than a roc

as for a stalker, without the ring is probably like a tracker....

I guess I always thought the ring was for stability, as a wasp is slower than a buzzz....or something...

hard to say....throw STALKERS!!!

The Buzzz vs Wasp is the best example of bead vs non bead, they are basically the same mold and the same speed, the bead just makes the Wasp more stable. Some Rocs/Sentinels are more stable than Buzzzs so it really depends in that case and they are different molds so thats not really the best example.

What is it with you and Stalkers? Its a decent disc, but really overlaps a Buzzz too much.

grodney
06-16-2010, 09:56 AM
VictorB, a question for you.

You know those marketing terms that Innova has: Speed, Turn, Fade, Glide? Let's talk about "Turn" and "Fade".

Given two discs, is it possible for one to BOTH "Turn" more, and "Fade" more, than the other disc? With the important assumption that everything else between the discs is equal (speed, spin, angle, etc.).

If so, what physical characteristics could/would cause such a difference?

????

garublador
06-16-2010, 10:28 AM
????I can't answer why, but the answer is, "Yes." The Eagle compared to a Teebird is a perfect example.

grodney
06-16-2010, 10:48 AM
I can't answer why, but the answer is, "Yes." The Eagle compared to a Teebird is a perfect example.

I know that's what the INNOVA chart claims. And I know that's what players observe. I just don't get it.


(In truth, it's not that I don't GET it, it's that I don't BELIEVE it. I think it's mis-perception. But I'm not afraid to say that I'm probably crazy and likely wrong!)

BrotherDave
06-16-2010, 12:49 PM
Most of you guys know a lot

Fixed. I didn't want anyone to think I was included that statement. :rolleyes:

I think there are a lot of variables together that alter stability.
This is what I suspect as well. There's probably some relationship that makes discs turn rather than one particular force or what not. The DV seems to be the more likely culprit than AV. It doesn't take a rocket scientist to see that a disc going too slow fades and that a disc going too fast turns. :|

Lithicon
06-16-2010, 02:28 PM
Speed and spin are required. They work together. But it's the speed of air moving over the disc which is really important. Speed and spin both contribute to this. Speed and Spin need to work together to create turn. The ratio I meant typically a harder throw will create more spin and a slower throw will create less spin. So the two r intrinsically linked typically.

The ratio won't be the same on short and long throws, you can alter spin just as easily as you can speed. Short throws can have lots or little spin, longer throws generally require more spin, but isn't completely necessary to a certain distance to have so much. Hence, why low snap players can still throw 400', but when they really learn snap they'll push 450', 500'+.

Like I said in my earlier long post
Speed is the main contributing factor in turn. But, no speed alone won't make a disc turn. It needs a AV to determine which way it will turn and fade, and it also determines when it will turn and fade by the amount of spin on the disc at a given speed. But, it can stabilize also, such as manipulating snap so an under stable disc remains stable, then as the spin slows down, the speed takes over , coupled with Aoa, and because AV direction, the disc begins to turn. Then as the disc loses speed, some AV will still be there, the pressures shift and the disc begins to fade out. But, as mentioned there, Aoa has a key role. Because anyone that knows proper form, knows it requires nose angle manipulation. Aoa doesn't always determine turn, but it assist, or resist turn. Nose up, resist right turn, and assists in fading by ultimately slowing the disc down. Nose down can assist in right turn, and also assist in forward penetration, helps create lift, and "glide".

The way Garu explained the Hyzer flip sounds pretty spot on. But, all these factors together determine how, when, and why a disc will turn. That's about the only way I can see it. You can't really say equal spin and speed will make a true straight flight, none of us could know that. We have no way of measuring it. A ratio of spin and speed equal a true flight, but measuring that to know what it is would take some research, that wouldn't be so easy to do.

optidiscic
06-16-2010, 02:38 PM
I guess no one ever notices when I write the word typically

Lithicon
06-16-2010, 03:23 PM
I guess no one reads, because all this was explained.

optidiscic
06-16-2010, 04:14 PM
I think I am in agreement with Lithicon for the most part.

I will try to explain this in lay terms and explain the way I see it.

Picture a Nascar Track. Picture 2 Cars. Picture Me connected to one of the cars by a parasail. Picture VictorB connected to another car by a parasail. My driver is Lithicon and VictorB's driver is Brother Dave. There are hurricane winds moving from east to west. Now lets say that garublader is mad at me cause I called him garubladder so he sabotogues me and Lithicon's car. The race begins and Brother Dave is a mad man driving 225 mph and zipping around the track like a true North Carolina Redneck. Lithicon is trying but our car just will not get past 125 mph. The hurricane winds are moving at 100 mph from east to west. Every time me and lith go east with the wind we lose all lift and are feeling just 25 mph of lift and I almost fall to the ground like a lead Rhino. Everytime VictorB and Brother Drive drive with the wind VicB loses lift but still has 125 mph of wind to live him up (225-100)...Victor B flys by me as I am almost hitting the earth. When we hit the turn and finally are flying into the wind I am gaining lift again as the air rushes by at 225 mph (125 +100) but VicB is laughing his ass off at me as he gains more lift as the air flys by him at 325 mph (100 +225)....Everytime we make a lap we dip and rise but vicb rises more as he is both making more laps and rises more everytime he makes a lap....I rise but not as quickly as I am neither making as many laps to gain more lift and dont gain as much lift as VicB.

In essence every lap of the track (spin) produces another moment of lift
The wind goes faster when you fly into it than it does when its at your back. So speed affects the disc differently on either side of the disc...one side moves into the wind and moves faster and produces more lift meanwhile the other side of the disc is going slower and produces less lift.....this difference creates more lift on one side and the disc rises up on one side creating an anhyzer angle and you have turn Faster discs will make it further from the tee pad before turn begins...at the same time the speed and spin both work together to create lift and thus turn.

I know this is all a pretty dry read I hope my nascar parasailing example at least was entertaining if it wasnt informative.

optidiscic
06-16-2010, 04:15 PM
I guess no one reads, because all this was explained.

its funny I actually think I agree with you but its tough for me to illustrate my point online

Lithicon
06-16-2010, 04:56 PM
Lmfao, it was entertaining. But, I think it muddles the ability to comprehend some aspects. The two cars are two different disc, spinning at a different rate(going around the track at different speeds). But, how you're thinking of the car going around the track(seperating the portion of the wing going into the wind, and out of the wind), it's on one portion of the track, going around the track. While the car is going the constant speed around the track(rate of spin), yes going in and out of the air will affect it. As you said, the speed on one side(going into the wind) will always be greater and creates a pressure difference (which way is dependent upon the Aoa) which creates more lift one side. So the more you increase the over all speed of the disc, the more lift you create on this side going into the wind.

As you say the moment of lift, since the disc is constant wing going around, the lift is generated constantly, the amount of spin and Aoe is what determines the rate and which the lift affects the disc and how fast it turns.

The rotation of the disc doesn't exactly accelerate this process, as it's rate of spin alone will generate more stability more than it would assist in the creation of lift due to spinning faster. Although the spin is needed to create the lift, I don't think it adds much more, until the point the stability is increased due to more spin, due to gyroscopicness. But, it was entertaining and not far off if you can comprehend how you meant it.

BogeyNoMore
06-21-2010, 01:34 PM
:popcorn:
I've been enjoying the heck out of this thread! A bit tough to follow at times, but there’s a lot of good stuff here.

This is what I suspect as well. There's probably some relationship that makes discs turn rather than one particular force or what not. The DV seems to be the more likely culprit than AV. It doesn't take a rocket scientist to see that a disc going too slow fades and that a disc going too fast turns. :|

Where's a shocked looking smilie when you need one?
Never thought I’d see the day that Brother Dave would post something about Directional Velocity vs. Angular Velocity! Thanks for chiming in, Bro!

Ladies & Gentlemen, I think we have a convert.:hfive:

BrotherDave
06-23-2010, 01:45 AM
:popcorn:
I've been enjoying the heck out of this thread! A bit tough to follow at times, but there’s a lot of good stuff here.



Where's a shocked looking smilie when you need one?
Never thought I’d see the day that Brother Dave would post something about Directional Velocity vs. Angular Velocity! Thanks for chiming in, Bro!

Ladies & Gentlemen, I think we have a convert.:hfive:

Dude, I don't know what you are talking about, I am all about the physics up in this b-word.

http://img16.imageshack.us/img16/1299/discgolfphysics.jpg

Lithicon
06-23-2010, 02:53 AM
Holy **** Jesus in the butt with no lube, I love everything that's going on there. Was that a Stalker Car? Should have been a Stalker Van. You know they're the shiz!

VictorB
06-23-2010, 08:50 AM
This is what I suspect as well. There's probably some relationship that makes discs turn rather than one particular force or what not. The DV seems to be the more likely culprit than AV. It doesn't take a rocket scientist to see that a disc going too slow fades and that a disc going too fast turns. :|


example (and this is purely a numbers example)

a disc requires a dv of 10m/s to fly at its cruising speed. An av of 5rps is required to fly 'true' to the mold's capability. that would be a dv:av ratio of 2m/s:1rps.

the same disc is thrown at 2m/s, which is well below it's cruising speed. while it would make sense that the av would only require 1rps, the disc will never fly as it is truly intended because the cruising speed isn't being met. Anything over the 1rps required at this velocity will make the disc fly much more overstable. The dv:av ratio is really only applicable when cruising speed is being met or exceeded. All discs will fly much more overstable if their intended cruising speed isn't acheived. This would be comparable to throwing in a tailwind, since the relative air speed of the disc is actually lower than the actual non-relative velocity it is being thrown at.

this is mainly why knowing the requirements for a discs cruising speed is so crucial to being able to throw it properly in any condition.

Lithicon
06-23-2010, 08:02 PM
Victor, that's all lies! Dave explained it correctly with his Stalker Car demonstration!

sidewinder22
06-23-2010, 08:11 PM
Dude, I don't know what you are talking about, I am all about the physics up in this b-word.

http://img16.imageshack.us/img16/1299/discgolfphysics.jpg

Why is the Kitty shocked and beheaded?

BogeyNoMore
06-26-2010, 10:51 PM
Dude, I don't know what you are talking about, I am all about the physics up in this b-word.

http://img16.imageshack.us/img16/1299/discgolfphysics.jpg

Best post ever regarding the the physics of a throw!
:thmbup: LOL!!

HeartlessCynic
06-26-2010, 10:55 PM
Why is the Kitty shocked and beheaded?

Wouldn't you be shocked to see you were about to be beheaded?

BogeyNoMore
06-26-2010, 10:56 PM
example (and this is purely a numbers example)

a disc requires a dv of 10m/s to fly at its cruising speed. An av of 5rps is required to fly 'true' to the mold's capability. that would be a dv:av ratio of 2m/s:1rps.

the same disc is thrown at 2m/s, which is well below it's cruising speed. while it would make sense that the av would only require 1rps, the disc will never fly as it is truly intended because the cruising speed isn't being met. Anything over the 1rps required at this velocity will make the disc fly much more overstable. The dv:av ratio is really only applicable when cruising speed is being met or exceeded. All discs will fly much more overstable if their intended cruising speed isn't acheived. This would be comparable to throwing in a tailwind, since the relative air speed of the disc is actually lower than the actual non-relative velocity it is being thrown at.

this is mainly why knowing the requirements for a discs cruising speed is so crucial to being able to throw it properly in any condition.


Thanks - sometimes you just gotta plug some numbers into an equation to understand how things behave. Also explains why those higher speed discs always seem so overstable, because most people can't get them to their intended speed.

BogeyNoMore
06-26-2010, 11:01 PM
Wouldn't you be shocked to see you were about to be beheaded?

To misquote Dirty Harry, "Nothing wrong with beheading, as long as the right people are getting beheaded."

sidewinder22
06-26-2010, 11:43 PM
Wouldn't you be shocked to see you were about to be beheaded?

You wouldn't see you've been beheaded until after it happened. ;) I wouldn't be shocked, more like pissed.

HeartlessCynic
06-26-2010, 11:47 PM
You wouldn't see you've been beheaded until after it happened. ;) I wouldn't be shocked, more like pissed.
Thus the "about to be beheaded". See it coming and you'd be like "OH SHI..."

grodney
08-25-2010, 08:58 AM
Rodney,

I'm glad you chimed in. I respect your knowledge and experience. Now I don't know what's correct. I'm not saying you're wrong, but can you cite any external evidence to support the claims of your first 2 points?

Yes: Faith.

jtencer
08-25-2010, 12:24 PM
What I really want to know is what disc features contribute to different flight characteristics.
SPEED
GLIDE
TURN
FADE
Stability

Thanks in advance

Speed: A measure of the drag force (At the design speed I would guess)
Glide: A measure of the lift force (particularly at low speeds)
Stability: Has to do with the moment of inertia of the disc (Higher moment => more stability)

Turn/Fade: Flight characteristics that are a consequence of stability (mostly) but also vary somewhat due to interactions with speed and glide. Basically, stability will give you a good idea of how the disc should be thrown but the actual flight path varies considerably because of differences in speed and glide.

jtencer
08-25-2010, 12:31 PM
I read a blurb recently about pitchers throwing curve balls. This has to do with understability in that the same principle applies, at least to beat discs. It's called the "M____ Effect" (can't remember the name of it), but it says that the air pressure differs and causes the ball to move to the lower air pressure area and the disc's wing with the lower air pressure (R for RHBH throw) to dip in that direction.

That's what I can add.

The magnus effect is very small and is not the reason that discs turn and fade. The reason is conservation of angular momentum causing precession (tilt). A girl out of UC-davis wrote a master's thesis on it a couple years back if you want to see the math.

hig2a4life
08-25-2010, 01:57 PM
Lol....guy...I can manipulate a wide rim disc without the use of snap....but you think everything is in some text book...keep on knowing everything...no wonder you say your game is weak...the best players...are the best learners...and you are far from letting anything pass through the discdome you speak so highly of having

Snap works best in wind situations since the disc is able to cut through the air better...how about them apples?...no snap...wide rim...wind...disc go bye bye....

I try to tell my students like I will tell you grasshopper...snap is later...first learn technique....and watch the LithiconDiscGolfShow too

I seriously hope you're high when you write posts. If you're not getting snap on all of your shots, you're most likely strong-arming and most likely not playing very well. Snap is not something that is specific to playing in the wind, it's something that is part of proper disc throwing technique that you should aim to create on every throw. Also, you must have no clue how discs work if you think snap alone will make you "cut through the air." If you're playing into a headwind and you get decent snap on something understable, you're going to find yourself throwing an unintentional roller. The disc will turn and burn. I just have to laugh at everything you post. "snap is later...first learn technique," is the single dumbest piece of advice I have ever seen in this forum. Learning technique means learning how to throw with snap. If you take your time trying to strong arm everything and then attempt to add in snap later, you're going to waste many years of disc golf being absolutely terrible. I feel like you must know this well if you truly believe that snap is situational and should only be taught after years of throwing it bad.

Lay off the weed and try to contribute something useful to these forums.

grodney
08-27-2010, 12:30 PM
Speed: A measure of the drag force (At the design speed I would guess)
Glide: A measure of the lift force (particularly at low speeds)
Stability: Has to do with the moment of inertia of the disc (Higher moment => more stability)

Turn/Fade: Flight characteristics that are a consequence of stability (mostly) but also vary somewhat due to interactions with speed and glide. Basically, stability will give you a good idea of how the disc should be thrown but the actual flight path varies considerably because of differences in speed and glide.

You know those marketing terms that Innova has: Speed, Turn, Fade, Glide? Let's talk about "Turn" and "Fade".

Given two discs, is it possible for one disc to BOTH "Turn" more, and "Fade" more, with respect to the other disc? With the important assumption that everything else between the discs is equal (speed, spin, angle, etc.).

If so, what physical characteristics could/would cause such a difference?

I wrote the UC-Davis girl and asked her. She said she'd have to think about it. That was 4 years ago.

optidiscic
08-27-2010, 01:13 PM
You know those marketing terms that Innova has: Speed, Turn, Fade, Glide? Let's talk about "Turn" and "Fade".

Given two discs, is it possible for one disc to BOTH "Turn" more, and "Fade" more, with respect to the other disc? With the important assumption that everything else between the discs is equal (speed, spin, angle, etc.).

If so, what physical characteristics could/would cause such a difference?

I wrote the UC-Davis girl and asked her. She said she'd have to think about it. That was 4 years ago.

I think the answer to your question 4 yrs ago became the Katana......good thing you didnt ask the UC-Davis gal for a date.....I have been waiting for yrs for some girls to call me!

biscoe
08-27-2010, 01:17 PM
when thrown backhand (as if anyone does) the epic demonstrates a good bit of high speed turn and then fades like a shot duck when it slows down.

atl scott
08-27-2010, 01:24 PM
I seriously hope you're high when you write posts.

NateDiscFlip is the reason I figured out how to block users on this site...

Disc Dog
08-27-2010, 02:48 PM
I have question. But please understand I am not a physics Phd. I am a laymen who reads and is not as dumb as some with Phd's would suppose. ( if you would like a debate on Maslow's Hierarchy of Needs, The Peter Principle, or the Law's of Thermodynamics I can hold my own)

I have read every post here and most in the other threads about this subject and I think:\ I have a basic grasp of the ideas. But I was raised around sailboats and there is a very common misconception that the
wind pushes the boat. This is only true when the wind is directly behind the boat. When you are traveling with the wind to the side, such as when tacking, you actually are being pulled into a vacumn that is created on the downwind side of the sail. This is created because the sail blocks the air flow causing the pressure to drop on the leeward side and the boat moves into that spot. If that is true of a sailboat would that not also be true on a disc? The air moves over a disc causing lift and the spin allows the disc to move through the air without causing a directional change (fade). As the spin decreases and it can no longer compensate for the leeward sides lower pressure and lighter weight the result would be a fade into that lower pressure. Thus causing a directional change we call fade.

Am I way off here? Or is this contributing factor?

Disc Dog
08-27-2010, 02:50 PM
Like Garu said, it won't help.

Your decision to throw a disc because a wing angle of X* makes it less stable, than a disc with X.XX* of wing angle for a particular anhyzer shot doesn't mean it will perform that shot any better, if you don't have technique to make it work, lol. Also, ask any pro how much they understand about disc physics and I'd say in terms of our classifications of terms we apply to them, they have a great understanding. But, in a scientific terms I'd be willing to bet that most of them don't know, and don't care.

Because, after practicing with a disc they'll get an idea of how the disc will perform in their hands. Understanding which disc perform better could make you come to a conclusion of which disc just might be better suited to make a particular shot, or be more versatile. But, everyone else can get that knowledge much easier by practice, lol. Over thinking some things lead to failure. Determining which disc to pull out because of it's profile, or wing angles, or dome really isn't any different than saying. Well, this particular shot I can make my Roc flip just enough, "BING, use a Roc." One method is just easier and the other won't have that much affect over the competition as long as they know how and why to perform a certain shot in a given condition with a particular disc without knowing the small nuances of scientific physics of flight.

All this is trumped by your physical and mental capacity to perform the shot. Having the knowledge of how to throw certain lines, how to manipulate your form. And, then ultimately in the end being able to physically perform the shot. The variables in your throw you have to over come can make or break the throw completely. The throw could make the disc work or not. Knowing you could perform the shot, you could argue that you might not know what disc to throw just because you know how to throw, and can. Well, understanding the scientific physics won't make that much easier, as I said earlier anyone can get that knowledge easier by practice.

Over all the knowledge gained by the scientific data from how or why a disc flies the way it does, it trumped by your physical ability to perform the shot. Looks good on paper, and in your head. But, until you can go out and do it, it won't make a bit of difference. Then you can explain why it done it to someone, and they'll look at you and laugh. I do fully understand the search for knowledge. I like to know how things work myself.:sick:

I would take umbridge with your statement above about practice and an understanding of flight characteristics.

You state "Because, after practicing with a disc they'll get an idea of how the disc will perform in their hands. Understanding which disc perform better could make you come to a conclusion of which disc just might be better suited to make a particular shot, or be more versatile. But, everyone else can get that knowledge much easier by practice, lol." This can only apply if have the disc to practice with. The cost of purchasing every disc on the market to try is prohibitive. Having even a basic knowledge of flight characteristics would alleviate much expense and time by enabling a person to pick the disc that best suits their ability.

While the marketing strategies of the manufactures is not precise it does allow a person some guidance in making a proper decision in their disc selection. Once they have begun and therefore go from beginner to novice to intermediate etc. They can continue to choose discs with the knowledge they have gained about discs and their experience. So to state categorically that this knowledge is not necessary is a falicy.

sidewinder22
08-27-2010, 03:18 PM
I have read every post here and most in the other threads about this subject and I think:\ I have a basic grasp of the ideas. But I was raised around sailboats and there is a very common misconception that the
wind pushes the boat. This is only true when the wind is directly behind the boat. When you are traveling with the wind to the side, such as when tacking, you actually are being pulled into a vacumn that is created on the downwind side of the sail. This is created because the sail blocks the air flow causing the pressure to drop on the leeward side and the boat moves into that spot. If that is true of a sailboat would that not also be true on a disc? The air moves over a disc causing lift and the spin allows the disc to move through the air without causing a directional change (fade). As the spin decreases and it can no longer compensate for the leeward sides lower pressure and lighter weight the result would be a fade into that lower pressure. Thus causing a directional change we call fade.

Am I way off here? Or is this contributing factor?

You are pretty close with that analogy. Generally there is drag/lift on left side of the disc(RHBH) and eddies on the right side with the disc spinning which is one reason a disc may turn right with spin. It basically takes a combination of speed, spin and wing design for HS turn.

Disc Dog
08-27-2010, 03:21 PM
:thmbup:*Disc Dig feels IQ raise to new heights*

sidewinder22
08-27-2010, 03:30 PM
Given two discs, is it possible for one disc to BOTH "Turn" more, and "Fade" more, with respect to the other disc? With the important assumption that everything else between the discs is equal (speed, spin, angle, etc.).

If so, what physical characteristics could/would cause such a difference?

I wrote the UC-Davis girl and asked her. She said she'd have to think about it. That was 4 years ago.

Not really without putting some oat on one disc or changing the speed. Turn and Fade are pretty dependent on each other thrown the same. You might get a Katana to turn and fade more than a Tbird but its not thrown the same and are different speed discs.

hangwind
08-27-2010, 04:00 PM
Speed = drag (less lift at slow speed)
Glide = lift (can be a combination of speed and stability)
Turn = curved flight path
Stability = how resistant the flight of the disc is to go from a straight line flight path
Fade = loss of stable flight as the disc slows at the end of the flight

All intra-related.

Good topic.

BogeyNoMore
08-27-2010, 04:55 PM
You know those marketing terms that Innova has: Speed, Turn, Fade, Glide? Let's talk about "Turn" and "Fade".

Given two discs, is it possible for one disc to BOTH "Turn" more, and "Fade" more, with respect to the other disc? With the important assumption that everything else between the discs is equal (speed, spin, angle, etc.).

If so, what physical characteristics could/would cause such a difference?

I wrote the UC-Davis girl and asked her. She said she'd have to think about it. That was 4 years ago.

Not really without putting some oat on one disc or changing the speed. Turn and Fade are pretty dependent on each other thrown the same. You might get a Katana to turn and fade more than a Tbird but its not thrown the same and are different speed discs.

If there's ANY truth whatsoever to Innova's numbering scheme, or the LSS and HSS numbers posted on Joe's Flight Chart and DiscGolfCenter's Flight Characteristics, it would seem that High Speed Turn is not necessarily directly linked to Low Speed Fade. I would imagine there are several variables that affect both similarly, but I can't imagine the two vary directly and in lockstep with each other.

Let's not discount practical knowledge: Most of us have thrown different discs that have similar high speed turn characteristics, but entrely different low speed fade characteristics.

While far from being solid empirical data, and things like wind that's substantially different at the end of the flight vs. the middle of the flight, or greater altitude at the end leading to increrased fade, etc., might account for some of these differences, those variables have less effect when the number of observations (sample size) is large enough.

sidewinder22
08-27-2010, 07:02 PM
If there's ANY truth whatsoever to Innova's numbering scheme, or the LSS and HSS numbers posted on Joe's Flight Chart and DiscGolfCenter's Flight Characteristics, it would seem that High Speed Turn is not necessarily directly linked to Low Speed Fade. I would imagine there are several variables that affect both similarly, but I can't imagine the two vary directly and in lockstep with each other.

Let's not discount practical knowledge: Most of us have thrown different discs that have similar high speed turn characteristics, but entrely different low speed fade characteristics.



There are slight speed(wing length) variations that account for the different turn/fade numbers within the same speed rated discs. For instance the eagle vs teebird are both rated speed 7, but the eagle is has a slightly shorter wing making it slightly slower and easier to turn while it fades hard when it slows down. Now say you don't get the eagle up to its 7 speed rating, it has no high speed turn and fades out fast.

The numbers from innova and joe's aren't exactly scientific with no bias either. There is no way to throw all those discs exactly as they are supposed to be flown and the number of other variables is high. Innova rates both the Teebird and TL with a 0 HS turn. You have to be crazy to believe the TL has no HS turn.

jubuttib
08-27-2010, 07:46 PM
Not really without putting some oat on one disc or changing the speed. Turn and Fade are pretty dependent on each other thrown the same. You might get a Katana to turn and fade more than a Tbird but its not thrown the same and are different speed discs.
They're linked somewhat, but it's not impossible. For example my medium IONs are both more HSS and less LSS than my soft ION, which easily turns more but also hooks way harder when it slows down. And I do believe I throw both of them the same, and that they're the same speed.

sidewinder22
08-27-2010, 08:14 PM
They're linked somewhat, but it's not impossible. For example my medium IONs are both more HSS and less LSS than my soft ION, which easily turns more but also hooks way harder when it slows down. And I do believe I throw both of them the same, and that they're the same speed.

Different plastic will change flight which is another variable. Soft plastic will flex and tend to turn over/less gyroscopic, but loses speed faster for more fade.

JHern
09-03-2010, 02:29 AM
...What I really want to know is what disc features contribute to different flight characteristics.
SPEED
GLIDE
TURN
FADE
Stability


On disc ratings and actual physical flight properties...

Note that Innova's rating system, and Joe's Flight Chart, and all other systems, are only subjective and relative. Speed=5 simply means the disc seems to have less drag than Speed=6, and more than Speed=4. These numbers are worked out by throwing in a field, and the numbering guru scratches his head, squints a little, and says "I'll call this a 4" or "I'll give this a 2," etc.. Nothing fancy here, it is just a way of characterizing characteristics of the disc that people think are important for practical purposes. Of course, this is just fine for most uses. But, there is no connection between these numbers and actual physically measurable quantities of disc flight. It might be possible to do this one day, but more work needs to be done first to study how real physical quantities and parameters governing disc flight affect things we might call speed, glide, turn, fade, etc..

You can describe the shape of any disc using a single line, and applying axi-symmetry to it sweeps out the shape of the full disc (except for weird discs like the Epic that aren't axi-symmetric). To every disc belongs a set of functions that describe the air drag (proportional to the disc's actual wind speed-squared, also nose angle sensitive), the physical lift (in units of lbs or Newtons, also proportional to speed-squared and nose angle sensitive), and the net torques on the disc (also a function of speed and nose angle). It is the torques on the disc that make it turn or fade...the rate of turning or fading is inversely proportional to the spin and the moment of inertia (i.e., how much mass/plastic is distributed on the outside relative to the inside).

In principle, if I had access to a super-computer I could simulate the aerodynamics of each disc shape, and calculate all of the above quantities. Then I could predict exactly how that disc shape should fly in real life. If the model is really good, then we would expect a good agreement. This would be a fun way to learn about how disc shape changes the flight characteristics.

Another way of doing things is to set the disc in a wind tunnel and put some instruments to measure the above quantities directly. This is probably much easier than doing a super-computer simulation, however, the computer would help you to understand what the air is actually doing around the disc and why different shapes yield different net forces and torques on the disc.

In any case, say you did either of the above with 500 different molds and you had their shapes stored in some sort of parameterized set of values. So long as the shape variations run the gamut in terms of yielding all sorts of flight properties, then you could in principle use all that data to figure out how each aerodynamical property changes with respect to changes in disc shape. Interestingly, you could even tune a disc's shape using this data in order to get certain aerodynamical behaviors by an inversion process.

I'd love to do this work myself, but there is nobody willing to pay me to do it, and I can't afford to spend that much time without a higher level of support. If I could do it, then I could answer your question properly, and I could even define a completely new system to describe the properties of a disc that could actually be used to predict exactly how it will fly if thrown with X hyzer, Y nose angle, and Z speed. This would be superior to the relative subjective ratings currently in use by Innova and by Joe's Flight Chart. More interestingly, however, with the real models in hand it should also be possible to try and use the old subjective ratings, by comparing with actual physical quantities, and generate a mapping between the two.

Jungle Tim
09-08-2010, 05:05 PM
I don't know. I don't know of an instance where it's been measured. My best guess is that forehand shots tend to turn over more because people have more OAT in their forehand throws.

IMO, this is the most important quote of the thread so far:

Not sure if anyone has mentioned this - but there was a thread about measuring spin about a year or 2 ago on DGR.

The guy, i believe he was a big arm european, put a rotational measuring device on the middle of his disc with a dragging tail fin. When thrown, the fin stayed co-linear to the direction of travel whilst the number of revolutions were counted by the measuring device with the tail fin as reference.

I *think* that he concluded that there was absolutely heaps more spin on a backhand throw...

zenbot
09-08-2010, 05:25 PM
On disc ratings and actual physical flight properties...

Note that Innova's rating system, and Joe's Flight Chart, and all other systems, are only subjective and relative. Speed=5 simply means the disc seems to have less drag than Speed=6, and more than Speed=4. These numbers are worked out by throwing in a field, and the numbering guru scratches his head, squints a little, and says "I'll call this a 4" or "I'll give this a 2," etc.. Nothing fancy here, it is just a way of characterizing characteristics of the disc that people think are important for practical purposes. Of course, this is just fine for most uses. But, there is no connection between these numbers and actual physically measurable quantities of disc flight. It might be possible to do this one day, but more work needs to be done first to study how real physical quantities and parameters governing disc flight affect things we might call speed, glide, turn, fade, etc..

You can describe the shape of any disc using a single line, and applying axi-symmetry to it sweeps out the shape of the full disc (except for weird discs like the Epic that aren't axi-symmetric). To every disc belongs a set of functions that describe the air drag (proportional to the disc's actual wind speed-squared, also nose angle sensitive), the physical lift (in units of lbs or Newtons, also proportional to speed-squared and nose angle sensitive), and the net torques on the disc (also a function of speed and nose angle). It is the torques on the disc that make it turn or fade...the rate of turning or fading is inversely proportional to the spin and the moment of inertia (i.e., how much mass/plastic is distributed on the outside relative to the inside).

In principle, if I had access to a super-computer I could simulate the aerodynamics of each disc shape, and calculate all of the above quantities. Then I could predict exactly how that disc shape should fly in real life. If the model is really good, then we would expect a good agreement. This would be a fun way to learn about how disc shape changes the flight characteristics.

Another way of doing things is to set the disc in a wind tunnel and put some instruments to measure the above quantities directly. This is probably much easier than doing a super-computer simulation, however, the computer would help you to understand what the air is actually doing around the disc and why different shapes yield different net forces and torques on the disc.

In any case, say you did either of the above with 500 different molds and you had their shapes stored in some sort of parameterized set of values. So long as the shape variations run the gamut in terms of yielding all sorts of flight properties, then you could in principle use all that data to figure out how each aerodynamical property changes with respect to changes in disc shape. Interestingly, you could even tune a disc's shape using this data in order to get certain aerodynamical behaviors by an inversion process.

I'd love to do this work myself, but there is nobody willing to pay me to do it, and I can't afford to spend that much time without a higher level of support. If I could do it, then I could answer your question properly, and I could even define a completely new system to describe the properties of a disc that could actually be used to predict exactly how it will fly if thrown with X hyzer, Y nose angle, and Z speed. This would be superior to the relative subjective ratings currently in use by Innova and by Joe's Flight Chart. More interestingly, however, with the real models in hand it should also be possible to try and use the old subjective ratings, by comparing with actual physical quantities, and generate a mapping between the two.
Once I find the giant box of money that I'm pretty sure is buried in my back yard you've got yourself a job.

BTW Thanks for posting. You always explain things very well so even dumb guys like me can follow. Your 300' thread has helped my drive more than anything.