Physics question

[gainer 0]

Here goes, why do you lose more altitude in a slow 360 than a fast 360.

I was in a CP course over the weekend and one of the students asked this question and nobody had the answer.

[Cueb 0]

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Here goes, why do you lose more altitude in a slow 360 than a fast 360.

I was in a CP course over the weekend and one of the students asked this question and nobody had the answer.

It takes time to get to the terminal speed of certain flight mode. Should you do a fast turn the duration of the turn is slower and it doesn't necessarily have the time to get to the speed. Keeping it in the dive longer lets you take advantage of the gravity fully. It takes 8 to 10 seconds to get to terminal speed in free fall(just a guess, correct me if you know better numbers), for example, and the same idea applies here. Of course the terminal velocity would be lower so it doesn't take so long.

[superstu 0]

think of it this way, when you floor it and drop the clutch in a hot rod you spin the tires out and don't go anywhere. but when you do things a little slower and smoothly then you can actually get off the line and move. do it too slowly though then you stall the car and lose speed/ don't go anywhere.

Slip Stream Air Sports
Do not go softly, do not go quietly, never back down

[frost 1]

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Here goes, why do you lose more altitude in a slow 360 than a fast 360.

I was in a CP course over the weekend and one of the students asked this question and nobody had the answer.

Uhm... Why did i cover more distance after driving for an hour vs 30 minutes? Could it be that it's because I spent more time traveling? :)

[wildcard451 0]

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Here goes, why do you lose more altitude in a slow 360 than a fast 360.

I was in a CP course over the weekend and one of the students asked this question and nobody had the answer.

Uhm... Why did i cover more distance after driving for an hour vs 30 minutes? Could it be that it's because I spent more time traveling? :)

You can travel through time?

[AggieDave 6]

Sure he can, but his time machine was built out of a Zaporozhets instead of a Deloreon.

--"When I die, may I be surrounded by scattered chrome and burning gasoline."

[frost 1]

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Sure he can, but his time machine was built out of a Zaporozhets instead of a Deloreon.

That's a state secret! How did you know that?!

before: http://www.prizraks.clan.su/_fr/1/0053879.jpg

after: http://www.pridurok.info/uploads/posts/2009-05/1242955140_glamour-zaporozhets-dlja-blondinok_1.jpg

[Rdutch 0]

because your in a dive longer. If you really want to rack your brain, try and figure: why is your roll out shorter on a slow 60 than a fast one? If no one gets it Ill respond.

Ray
Small and fast what every girl dreams of!

[mgattini 0]

Because the "slow" 360 has you turning for more time vs the "fast" 360....it is a matter of how much time you are spending in the dive, the more time spent the more altitude lost, IMHO. Hope this answers your question, if not let me know.

[quade 3]

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You can travel through time?

We all do. We just can't pick the direction or speed at which it happens. At least not in any way that really matters.

quade -
The World's Most Boring Skydiver

[Martini 0]

Gee, all the pat answers like "because you're in a dive longer" or "Why did i cover more distance after driving for an hour vs 30 minutes? Could it be that it's because I spent more time traveling? :) " Really cute, really worthless.

The slower turn has a shallow dive angle but for a longer time, the faster turn has a steeper dive for a shorter time. Logically the end result COULD be the same. Or not. Because you don't necessarily lose more altitude in a slow 360 vs a fast one. It's just a common assumption, one that won't be true in all cases. It also doesn't address the canopy dive angle and speed at the end of the 360, the energy left in the system. Kinda important if you're swooping. IMO

Sometimes you eat the bear..............

[muff528 3]

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Gee, all the pat answers like "because you're in a dive longer" or "Why did i cover more distance after driving for an hour vs 30 minutes? Could it be that it's because I spent more time traveling? :) " Really cute, really worthless.

The slower turn has a shallow dive angle but for a longer time, the faster turn has a steeper dive for a shorter time. Logically the end result COULD be the same. Or not. Because you don't necessarily lose more altitude in a slow 360 vs a fast one. It's just a common assumption, one that won't be true in all cases. It also doesn't address the canopy dive angle and speed at the end of the 360, the energy left in the system. Kinda important if you're swooping. IMO

Nothing particularly bad about any of those answers if they are taken to be hypotheses based on the OPs perceived observations. Your statements suggest that the next step should be to conduct experiments (measurements) to confirm or refine the OPs observations. Use different canopies (types and sizes) with various wingloading, inputs, and turn rates. Then theories can be applied to attempt to explain the data gathered resulting from actual measurements. Kinda takes the fun out of it.

[frost 1]

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Gee, all the pat answers ... Really cute, really worthless.

Logically the end result COULD be the same. Or not.

True. That's why people with a ton more experience normally wait for someone like you, who is knowledgeable in theory, to give a worthy LOGICALLY definitive answer that ends in "could be or not".

[davelepka 4]

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The slower turn has a shallow dive angle but for a longer time, the faster turn has a steeper dive for a shorter time. Logically the end result COULD be the same.

I'm not sure about your assumption.

If we're talking about diving turns (front risers), there's no way to do a constant speed diving turn. The turn will always be accelerating until you hit the canopy's terminal velocity, at which point the greater drag of the canopy will push it back over your head, unless, of course, you decrease the AOA further (add input), and create a higher terminal velocity.

So in a quick 360, you'll apply a large input for a short amount of time, and you'll be accelerating the entire time, but not reaching the terminal velocity of the canopy.

In a slow 360, you'll start with a moderate input, and in order to continue the turn, you'll steadily increase that input to maintain the turn. Your canopy will be 'riding' the increasing wave of terminal veloicity as you apply greater and greater input.

So at the end of your slow turn, when your input equals the same input you gave at the beginning of the quick turn, you're already at the (or very close to) the terminal velocity of the canopy for that input, the same terminal velocity you didn't reach with the quick turn.

Higher speed for a longer time along a descending line equals more altitude loss.

[dharma1976 0]

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Gee, all the pat answers ... Really cute, really worthless.

Logically the end result COULD be the same. Or not.

True. That's why people with a ton more experience normally wait for someone like you, who is knowledgeable in theory, to give a worthy LOGICALLY definitive answer that ends in "could be or not".

he is a reincarnated German philosopher

D

http://www.skyjunky.com

CSpenceFLY - I can't believe the number of people willing to bet their life on someone else doing the right thing.

[muff528 3]

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Gee, all the pat answers ... Really cute, really worthless.

Logically the end result COULD be the same. Or not.

True. That's why people with a ton more experience normally wait for someone like you, who is knowledgeable in theory, to give a worthy LOGICALLY definitive answer that ends in "could be or not".

he is a reincarnated German philosopher

D

"Nietzsche is dead!", God. (and he's probably not coming back)

[phoenixlpr 0]

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If we're talking about diving turns (front risers), there's no way to do a constant speed diving turn.

Why do you assume that only could be a front riser turn?
I can get more speed with a slow rate harness turn than a quick snap 360 with a single front riser.

[davelepka 4]

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Why do you assume that only could be a front riser turn?
I can get more speed with a slow rate harness turn than a quick snap 360 with a single front riser

What I said actually applies to harness turns as well. Any 'accelerating' or 'diving' turn presents the problems of hitting the canopy's terminal velocity, and either needing more input (accelerating) or risk swinging back under the wing and pitching the nose up and out of the dive.

A toggle, or rear riser turn, on the other hand does not suffer from this problem. Those are 'braked' turns (not 'flat' turns), in which you are braking one side of the canopy to prodcue the turn. It does not count on the canopy to accelerate to maintain the turn, so you can achieve a steady state, consistant turn.

This difference is also why front riser or hanress turns are more 'divey' then toggle or rear riser turns, and the main reason that front riser or hanress turns are the choice for swooping.

The dive produced from a braked turn is more of a by-product of the wing getting ahead of the jumper as the one side flies around the braked side. This is why you can counter that dive by doing a flat turn, where the jumper compensates for the pitch change with toggle input.

The dive from an accelerating turn is an essential part of the manuver, and this is why there's no way to do a 'flat' front riser or harness turn, and why there's no way to not be accelerating during such turns.

[strop45 0]

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Gee, all the pat answers like "because you're in a dive longer" or "Why did i cover more distance after driving for an hour vs 30 minutes? Could it be that it's because I spent more time traveling? :) " Really cute, really worthless.

OK, so now try comparing a slow 360 with a fast 360 and level flight for a time so that both take the same overall time. Which costs the most altitude?

If you use toggles, then I think that the fast turn will cost more altitude as it induces more drag, and is less efficient.

Front risers? Rear Risers? Body position?

The difference between stupidity and genius is that genius has its limits." -- Albert Einstein

[Martini 0]

Well, I got what I wanted here by being rude. Again. We just moved from mindless drivel to thoughtful discussion. BTW I find the original question to be fascinatingly complex but I'm still more interested in what's going on at the end of a 360. And some hard data would be nice. To use extreme examples of why this aint simple shit:

1) I can make ANY canopy "dive" 2000 feet in a 360 using brakes, risers or harness input just by using very tiny inputs.

2) I can, in my experience, lose a lot more altitude doing a fast 270 to initiate a steep dive and letting the dive continue to a 360 than I could using a gentle input for four times as long.

My simplest take on this is based on acceleration, find the acceleration curve that gives the best result. Accelerate too quickly OR too slowly and you don't get the largest altitude loss per revolution or the most system energy. And the largest altitude loss per 360 won't neccesarily equate to the best swoop. (see example 1)

I'm not a reincarnated German philosopher, just a dyslexic agnostic insomniac. Stayed up all night wondering if there is a dog.

Sometimes you eat the bear..............

[muff528 3]

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Well, I got what I wanted here by being rude. Again. We just moved from mindless drivel to thoughtful discussion. BTW I find the original question to be fascinatingly complex but I'm still more interested in what's going on at the end of a 360. And some hard data would be nice. To use extreme examples of why this aint simple shit:

1) I can make ANY canopy "dive" 2000 feet in a 360 using brakes, risers or harness input just by using very tiny inputs.

2) I can, in my experience, lose a lot more altitude doing a fast 270 to initiate a steep dive and letting the dive continue to a 360 than I could using a gentle input for four times as long.

My simplest take on this is based on acceleration, find the acceleration curve that gives the best result. Accelerate too quickly OR too slowly and you don't get the largest altitude loss per revolution or the most system energy. And the largest altitude loss per 360 won't neccesarily equate to the best swoop. (see example 1)

I'm not a reincarnated German philosopher, just a dyslexic agnostic insomniac. Stayed up all night wondering if there is a dog.

Taking it to the limit......it is possible to open at 5000 ft., for example, and use up all of it with a single 360 degree revolution (or any fraction of that "spin"). Of course, you will use all 5000 ft. in straight flight, too, so figuring out what inputs combined with various wingloadings, wing shapes, etc. will give what results will be a little complex. (if you can read that last sentence and make any sense of it, please let me know what I meant

[Martini 0]

Taking it to the limit......it is possible to open at 5000 ft., for example, and use up all of it with a single 360 degree revolution (or any fraction of that "spin"). Of course, you will use all 5000 ft. in straight flight, too, so figuring out what inputs combined with various wingloadings, wing shapes, etc. will give what results will be a little complex. (if you can read that last sentence and make any sense of it, please let me know what I meant )

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Yes

Sometimes you eat the bear..............

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