How "breaking in" effects flight characturistics

[thirtydirtybirds]

What about material from the underside of the rim being worn away. Like how a beaded disc gets a smaller head after a while from the disc hitting the ground and removing little bits. Would this not then lower the plh, as there is less material below the parting line?

 

[sidewinder22]

Yeah, I figured that you are guessing on this. The problem with an explanation that involves the surface roughness of the disc causing, directly or indirectly, more lift, is that it would be asymmetrical due to the spin of the disc. The advancing side of the disc and the retreating side of the disc would be affected differently due to spin. If there were additional lift on the advancing side of a thrown disc, precession would cause the the disc to nose up, causing a more rapid onset of fade.

This is just something that would need to be explained away if, somehow, reduced friction drag is the mechanism by which beating in increases understability. Perversely, lift itself causes drag. Add lift, and you add drag. An additional wild card to be explained away.

Another thing that makes me question the skin friction theory is boating. Air is a much less dense fluid than water and surface treatments on boats generally just try to smooth the surface because the friction drag is such a small part of the equation that it generally doesn't merit any shark-skin-like treatment (though such things do exist). The vast majority of the drag comes from moving aside the water through which the boat must move. Discs, flying through air, experience even less drag from skin friction than boats.

You'll also notice that airplanes are simply smooth. Don't you think if the airlines could save fuel and gain added lift that they would scuff them up? The drag that a disc or airplane experiences is primarily, if not wholly, a result of the need to move air out of the way to let the disc/plane move through it.

I never said roughness increases lift, but it reduces drag. If anything it may also decrease lift. It basically makes the wing more slippery through the medium.

Boats float/skim on the surface, they aren't swimming underwater like submarines or sharks. There's a difference in what happens on the surface of the water vs being submerged underwater. This would be like comparing an airplane driving on the ground vs actually flying in the air... 2-D vs 3-D effects.

Airplanes likely have smooth wings because they want flight stability vs efficiency, otherwise they are probably going to have lots of air disasters with understable wings. Also scuffed wings would be harder to clean and de-ice.

 

[Doofenshmirtz]

I never said roughness increases lift, but it reduces drag. If anything it may also decrease lift. It basically makes the wing more slippery through the medium.

You've measured this right? However you rationalize this, you still have an assymmetry problem with skin drag as an explanation and another problem with the the negligible difference to which surface roughness might reduce drag, if at all.

Boats float/skim on the surface, they aren't swimming underwater like submarines or sharks. There's a difference in what happens on the surface of the water vs being submerged underwater. This would be like comparing an airplane driving on the ground vs actually flying in the air... 2-D vs 3-D effects.

This is just silly. Friction drag is friction drag, at the surface or below.

Airplanes likely have smooth wings because they want flight stability vs efficiency, otherwise they are probably going to have lots of air disasters with understable wings. Also scuffed wings would be harder to clean and de-ice.

Airplanes have smooth wings to reduce drag. But keep making stuff up.

 

[FlipFlat]

IIRC the scholarly articles written have stated that Magnus effect was measured as non-zero, but negligible in their calculations. IIRC they were also only tested a frisbee at like 45mph with low spin rates, so the speed and spin would be significantly below what pro disc golfer actually throw. The Magnus effect would "push or pull" the sidewall/wing of the disc sideways. This is a much smaller effect than a ball or cylinder would experience due to the height of the disc wing not being very tall like 2cm and relatively heavy compared to a basketball that has a much larger side spinning surface and relatively lighter mass for its overall size.

After reading more on this subject, and trying to understand all the physics going on here, the Magnus effect does seem to play a part. Though more likely a very small part, with other factors being of far greater significance.

 

[sidewinder22]

You've measured this right? However you rationalize this, you still have an assymmetry problem with skin drag as an explanation and another problem with the the negligible difference to which surface roughness might reduce drag, if at all.

The problem with an explanation that involves the surface roughness of the disc causing, directly or indirectly, more lift, is that it would be asymmetrical due to the spin of the disc. The advancing side of the disc and the retreating side of the disc would be affected differently due to spin. If there were additional lift on the advancing side of a thrown disc, precession would cause the the disc to nose up, causing a more rapid onset of fade.

Ok, I was originally correct about dimples increasing Magnus - in regard to the advancing and retreating side in axis of spin which would be "lift" in the sideways/horizontal plane of the disc to the right with clockwise spin. If you put sideways spin on a golf ball like a disc spins, the dimples increase the Magnus "lift" and drag causing sideways curve in the direction of spin.

The flight plate which is where the vertical lift is produced is perpendicular to spin direction and sees no spin to the airflow and the dimples/feathers reduce the greater horizontal lift drag. The vertical and horizontal lifts pseudo vector.

The tips of the disc gets smashed in with repeated hits which dulls the nose and rounds the edges/wing angles making them less concave which affects the CoP, and makes the disc less nose sensitive/sharp. This dulling of the nose and wing tips also happens to reduce the chord length and wing span(disc diameter) which will affect aerodynamic and gyroscopic stability, and the rated disc cruising speed. While the tips get rounded, the surfaces are roughed or feathered.

This is just silly. Friction drag is friction drag, at the surface or below.

Surface water has tension and the molecules are structurally different at the surface than below. Some insects hydroplane and glide on top the water surface. You can swim faster/more efficient underwater because there is no hydrodynamic friction from surface air bubbles and less turbulent wake is created.

Fish don't cruise for long distances along the surface as their wake will breach the surface making a more turbulent wave and splash and trash instead of the water flowing more smoothly or laminar all the way around them to help efficiently propel them forward. Dolphins and porpoise can efficiently cruise along the surface in a pendulum as they skip between being under the surface and above it spending less time at the surface itself and creating very little surface drag and wake. Boats skip or skim more above the water surface like a skipping stone and employ a combination of hydrodynamic and aerodynamic properties. Faster boats travel the more above the water surface to reduce surface tension drag and only the propeller is below the surface. Submarines travel faster and more efficient/less drag underwater than they can on the surface and essentially fly around underwater like an airplane. The drag of subs more closely resemble airplanes than boats. Boat wake might more closely resemble supersonic airplane wake though.

So whether you are a boat or sub you want to be further away from the surface to reduce drag. Meanwhile airplanes get a boost in lift and reduced drag from ground effect flying closer to the ground. On the opposite side of the spectrum you have the HyperSoar which skips along the top of the atmosphere at Mach 10 with super fuel efficiency using an oscillating flight path that utilizes gravity like a dolphin or bird.

Oscillating motions are more efficient moving through fluids than straight which is why I theorize the right amount of oscillating wobble can help efficiency and reduce drag by skipping or spiraling and oscillate between lift and gravity from weightless to heavy and produce longer gliding distance flight than a zero wobble straight flight can that is subject to more constant drag and weight. The parabolic shape of a disc makes for a very efficient oscillator, while spin makes for a very efficient stabilizer(at least until the mass distribution is disturbed enough from repeated mega hits to make it start increasing wobbling like an out of balance tire).

Airplanes have smooth wings to reduce drag. But keep making stuff up.

I'm not making this stuff up:

Feather roughness reduces flow separation during low Reynolds number glides of swifts.

In a wind tunnel, a plate's surface irregularities can suppress air turbulence, suggesting possible improvements for airplane wings.

Shark Skin Will Inspire Faster Swimsuits and Airplanes
http://www.popularmechanics.com/sci...pire-faster-swimsuits-and-airplanes-16792156/

In their tests, the team found that their artificial shark skin could increase swimming speed by 6.6 percent and reduce the energy expended by 5.9 percent. "We've proved for the first time that shark skin can reduce the energy needed for swimming," Lauder says.

Biomechanist Frank Fish at West Chester University in Pennsylvania, says scientists could use similar structures that could manipulate air flow to reduce drag or generate more lift. "This would be a benefit in rudders, airplane wings, fans, and wind turbines," he says.

 

[DG_player]

Engineers distinguish two types of drag force on an object moving through a fluid like air. A blunt object, such as a baseball, feels mostly "pressure drag," which arises from the difference between the oncoming air in front and the "sheltered" region in the wake just behind it. In contrast, a long, streamlined object, such as an airplane wing, feels mostly "friction drag" as its surfaces slide past slower moving air.

This is from one of the articles sidewinder posted. I believe it's fairly relevant to the conversation.

You can't really know for sure, because I do not believe there have been any wind tunnel tests or other experiments done to compare beat-in vs. new discs, but as I said before, I strongly doubt that beat in discs have any improvement in lift/drag performance. If it did, people would be beating in airplane wings as opposed to making them as smooth as possible.

 

[Nenja]

This is from one of the articles sidewinder posted. I believe it's fairly relevant to the conversation.

You can't really know for sure, because I do not believe there have been any wind tunnel tests or other experiments done to compare beat-in vs. new discs, but as I said before, I strongly doubt that beat in discs have any improvement in lift/drag performance. If it did, people would be beating in airplane wings as opposed to making them as smooth as possible.

Why don't you just whack you brand new overstable discs in the ground to get "that amazing unicorn Roc of dreams and doom flight"?

I'm quite sure we prefer a smooth ride in an airplane over a few percent of fuel efficiency.

My instincts tell me the smoother the more efficiently glide, however roughness feels like it could as opposed to smoothly slicing through the air get uplift from the turbulence. We have to keep in mind we throw frisbees and not flat objects, they're shaped to glide.

What kind of paint/surface treatment do they use for gliding airplanes?

 

[FlipFlat]

One thing i notice is all of my Ch t-birds end up losing the LSS before the HSS, with the exception of one of my Ch T-Birds. I have been trying to figure out why this happened is flight is now like a Eagle L not like a mellow T-bird like my others turn into. Looking at the two seasoned TBirds the only thing i can see that might explain it, is the T bird that lost its HSS first has many more deeper gouges in the nose area. And the flight plate and bottom wing is smoother (less surface scratching)on it. The other season T-bird that held on to it's HSS, and lost it LSS first like normally has way more surface scratches on the flight plate and the bottom of the wing and more dent like marks on the nose. Has anyone else experience this with a T-bird just wondering? Forgot to mention the PLH is the same.

 

[Frankp2491]

The thing I find interesting and confusing though is does this disc break in only when it smashes into something lol? Because my beginner DX set deff flies different than it did when I bought it and I notice it night and day however my champion discs are not flying favorably yet should I chuck them against trees lol? I know people say about. Aseball gloves the best glove is broken in over a long period of time but I want a more forgiving champion disc now not in a year haha but seriously though is there anyway to accelerate the break in phase of more expensive plastics

 

[slowplastic]

The thing I find interesting and confusing though is does this disc break in only when it smashes into something lol? Because my beginner DX set deff flies different than it did when I bought it and I notice it night and day however my champion discs are not flying favorably yet should I chuck them against trees lol? I know people say about. Aseball gloves the best glove is broken in over a long period of time but I want a more forgiving champion disc now not in a year haha but seriously though is there anyway to accelerate the break in phase of more expensive plastics

Scuff up the bottom edge on concrete or the edge of a curb/stairs. Dent the nose down by flicking it into wood or put a towel down on some concrete and flick it into that several times (bends the wings down/dents them slightly, but avoids chips and gouges). Sand it a little to get rid of the rough edges from the abuse. It'll definitely knock the new off of champ or star.

It'll get the flight like they've been used for a year, but they just won't get all the micro scratches on the surface that make them a little less slippery.

 

[Frankp2491]

Scuff up the bottom edge on concrete or the edge of a curb/stairs. Dent the nose down by flicking it into wood or put a towel down on some concrete and flick it into that several times (bends the wings down/dents them slightly, but avoids chips and gouges). Sand it a little to get rid of the rough edges from the abuse. It'll definitely knock the new off of champ or star.

It'll get the flight like they've been used for a year, but they just won't get all the micro scratches on the surface that make them a little less slippery.

I will deff use that wisdom next time i'm out on the course because I've been hesitant to throw my new stuff into the trees and f it all up lol now I know

 

[slowplastic]

I will deff use that wisdom next time i'm out on the course because I've been hesitant to throw my new stuff into the trees and f it all up lol now I know

Some discs have a really really thin plastic edge on the very bottom of the disc (the part that would sit on the ground if you just put it down) that people call "flashing"...this sharp edge is considered a molding imperfection and can also cause discs to fly more overstable than intended. I sand this off with sandpaper or on smooth concrete immediately when I get a new disc...I don't even bother throwing it without doing this typically since I know it can affect the flight and more importantly I have soft fingers and it hurts when I throw haha. But my point is...I pretty much have a disc roughed up right when it's out of the store and before it has seen its first throw.

Keep in mind that with the high end plastics discs tend to live most of their lives in the beat-in/sweet spot stage, so don't be concerned about getting them roughed up a bit, it just quickens them to getting to where they will end up being. Of course single nasty gouges and other random incidents can affect the flight in a strange way and make for a unique flight. That's why I'd suggest roughing up the bottom in a moderate and random way, along with moderate wing hits. Test it out after some beat in and see how much it has affected things. It'll then stay that way through normal use for quite some time...it's not like you're throwing it 70%+ power into a tree a few feet away 20 times in a round...at least I hope.