Forums: Skydiving Disciplines: Wing Suit Flying:
Glide Ratios?

 

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bertusgeert  (A License)

Dec 2, 2011, 12:25 PM
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Glide Ratios? Can't Post

I've been reading much less about wingsuits over the last few years, but was discussing aerodynamics with a buddy the other day when he asked me - what kind of glide ratios do those things get nowadays?

Well, I don't know. Can someone answer that? Just a quick question. Thanks!


phoenixlpr  (D 3049)

Dec 2, 2011, 12:35 PM
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Re: [bertusgeert] Glide Ratios? [In reply to] Can't Post

From .095 - 3+


kallend  (D 23151)

Dec 3, 2011, 12:16 PM
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Re: [phoenixlpr] Glide Ratios? [In reply to] Can't Post

In reply to:
From .095 - 3+

I submit that any GR < 1 isn't flying, but falling at an angle.


fasted3  (D 30104)

Dec 3, 2011, 6:04 PM
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Re: [kallend] Glide Ratios? [In reply to] Can't Post

In reply to:
In reply to:
From .095 - 3+

I submit that any GR < 1 isn't flying, but falling at an angle.
Quote:

Do you ever dive in your airplane? If so, at what point do you consider it falling at an angle, and at what point do you resume flying again?
Falling, stalling, flying dirty; I've been there, but flying a steep angle at high speed is still flying to me.


phoenixlpr  (D 3049)

Dec 4, 2011, 2:40 PM
Post #5 of 65 (2193 views)
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Re: [kallend] Glide Ratios? [In reply to] Can't Post

In reply to:
In reply to:
From .095 - 3+

I submit that any GR < 1 isn't flying, but falling at an angle.

Sure, Ask a glider! Under 10 it's not flying just controlled falling.Cool


Martini  (D 23756)

Dec 4, 2011, 6:13 PM
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Re: [kallend] Glide Ratios? [In reply to] Can't Post

Pretty bold move being the definer of the term. So in turn I submit that if you can't gain altitude you're not flying, only gliding. So nobody flies. If you're in an aircraft you aren't flying, you're riding in an aircraft. Regular skyjumping is falling. Wingsuits are gliders. Paragliders and hang gliders are aircraft. Looks to me like the birds are still the only ones doing the flying.


nickfrey

Dec 5, 2011, 12:04 AM
Post #7 of 65 (2144 views)
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Re: [Martini] Glide Ratios? [In reply to] Can't Post

Isn't there a quote something like, if riding in a boats not swimming how can riding in a plane be flying...


phoenixlpr  (D 3049)

Dec 5, 2011, 3:34 AM
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Re: [nickfrey] Glide Ratios? [In reply to] Can't Post

In reply to:
Isn't there a quote something like, if riding in a boats not swimming how can riding in a plane be flying...
Twisted, but true.Cool


piisfish

Dec 5, 2011, 3:36 AM
Post #9 of 65 (2111 views)
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Re: [kallend] Glide Ratios? [In reply to] Can't Post

In reply to:
In reply to:
From .095 - 3+

I submit that any GR < 1 isn't flying, but falling at an angle.
at least it is falling with "some" style... Laugh


granpasc

Dec 5, 2011, 4:26 AM
Post #10 of 65 (2099 views)
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Re: [phoenixlpr] Glide Ratios? [In reply to] Can't Post

A Porter with failure engine, it's already 13 Wink


Basjkall  (B 666)

Dec 5, 2011, 7:26 AM
Post #11 of 65 (2051 views)
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Re: [bertusgeert] Glide Ratios? [In reply to] Can't Post

We are defined as gliders:

In flight, a glider has three forces acting on it as compared to the four forces that act on a powered aircraft. Both types of aircraft are subjected to the forces of lift, drag, and weight. The powered aircraft has an engine that generates thrust, while the glider has no thrust.

In order for a glider to fly, it must generate lift to oppose its weight. To generate lift, a glider must move through the air. The motion of a glider through the air also generates drag. In a powered aircraft, the thrust from the engine opposes drag, but a glider has no engine to generate thrust. With the drag unopposed, a glider quickly slows down until it can no longer generate enough lift to oppose the weight, and it then falls to earth. - Stalling
The wings on a glider have to produce enough lift to balance the weight of the glider. The faster the glider goes the more lift the wings make. If the glider flies fast enough the wings will produce enough lift to keep it in the air. But, the wings and the body of the glider also produce drag, and they produce more drag the faster the glider flies. Since there's no engine on a glider to produce thrust, the glider has to generate speed in some other way. Angling the glider downward, trading altitude for speed, allows the glider to fly fast enough to generate the lift needed to support its weight.

(Newton's Third Law of Motion.)


(This post was edited by Basjkall on Dec 5, 2011, 7:58 AM)
Attachments: wingsection.jpg (26.3 KB)


kallend  (D 23151)

Dec 5, 2011, 8:17 AM
Post #12 of 65 (2029 views)
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Re: [Basjkall] Glide Ratios? [In reply to] Can't Post

In reply to:
We are defined as gliders:

In flight, a glider has three forces acting on it as compared to the four forces that act on a powered aircraft. Both types of aircraft are subjected to the forces of lift, drag, and weight. The powered aircraft has an engine that generates thrust, while the glider has no thrust.

In order for a glider to fly, it must generate lift to oppose its weight. To generate lift, a glider must move through the air. The motion of a glider through the air also generates drag. In a powered aircraft, the thrust from the engine opposes drag, but a glider has no engine to generate thrust. With the drag unopposed, a glider quickly slows down until it can no longer generate enough lift to oppose the weight, and it then falls to earth. - Stalling
The wings on a glider have to produce enough lift to balance the weight of the glider. The faster the glider goes the more lift the wings make. If the glider flies fast enough the wings will produce enough lift to keep it in the air. But, the wings and the body of the glider also produce drag, and they produce more drag the faster the glider flies. Since there's no engine on a glider to produce thrust, the glider has to generate speed in some other way. Angling the glider downward, trading altitude for speed, allows the glider to fly fast enough to generate the lift needed to support its weight.

(Newton's Third Law of Motion.)

Indeed, and a GR < 1 implies producing more drag than lift. Hardly a major achievement in aerodynamics.


bertusgeert  (A License)

Dec 5, 2011, 9:07 AM
Post #13 of 65 (2012 views)
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Re: [kallend] Glide Ratios? [In reply to] Can't Post

In reply to:
The wings on a glider have to produce enough lift to balance the weight of the glider. The faster the glider goes the more lift the wings make. If the glider flies fast enough the wings will produce enough lift to keep it in the air.

Ok, I'm gonna bite on this one. This is if you hold the variable of the type of wing constant. The other solution is to change the wing, and fly slower...like, perhaps, a paraGLIDER ;-)

I was under the impression (and hope) that there has been more improvement in glide ratios over the years. It would be interesting to know max glide ratio over time and how it's improved - seems it's tapered off?

One day we'll ridge soar in wingsuit configuration. Or perhaps even have enough control over attitude to be able to fly slow & thermal, and then tuck & dive like birds of prey.


Premier DSE  (D 29060)
Moderator
Dec 5, 2011, 10:20 AM
Post #14 of 65 (1985 views)
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Re: [bertusgeert] Glide Ratios? [In reply to] Can't Post

In reply to:

One day we'll ridge soar in wingsuit configuration. Or perhaps even have enough control over attitude to be able to fly slow & thermal, and then tuck & dive like birds of prey.

In a wingsuit? Not likely. We don't have the wingload/wingspan ability. We're fat, short by comparison to even the least efficient bird out there. More like Ostrich' than like osprey.


sdctlc  (D 16437)

Dec 5, 2011, 11:35 AM
Post #15 of 65 (1961 views)
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Re: Glide Ratios? [In reply to] Can't Post

Just for fun.....

http://www.youtube.com/watch?v=3fgcMNel64M

Crazy

Scott C.


Basjkall  (B 666)

Dec 5, 2011, 11:50 AM
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Re: [DSE] Glide Ratios? [In reply to] Can't Post

Use your head buddy, With the right angled ridge and wind speed it is possible. Wing suits can be made with huge cambered wings to get max lift, and very little sink and forward speed. Then it is also possible to land.

Its all about the relative speed to the ground..

Wait and see Wink


bertusgeert  (A License)

Dec 5, 2011, 12:11 PM
Post #17 of 65 (1940 views)
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Re: [Basjkall] Glide Ratios? [In reply to] Can't Post

In reply to:
Wait and see Wink

Exactly, I am of the same mind. Oftentimes I come across people who think some things will never be possible. I disagree. 200 years ago, horseless carriages were impossible to those same people, nevermind "flight". Look where we are now. So many possibilities.

It's just a matter of technology & knowledge.

Here's a fun one from Dave Prentice.

http://www.youtube.com/watch?v=mR3VPsipsoU


rehmwa  (D 12816)

Dec 5, 2011, 12:18 PM
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Re: [Basjkall] Glide Ratios? [In reply to] Can't Post

Yeah - Christian Bale did it in the Batman movie.


kallend  (D 23151)

Dec 5, 2011, 12:45 PM
Post #19 of 65 (1917 views)
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Re: [DSE] Glide Ratios? [In reply to] Can't Post

In reply to:
In reply to:

One day we'll ridge soar in wingsuit configuration. Or perhaps even have enough control over attitude to be able to fly slow & thermal, and then tuck & dive like birds of prey.

In a wingsuit? Not likely. We don't have the wingload/wingspan ability. We're fat, short by comparison to even the least efficient bird out there. More like Ostrich' than like osprey.

Even if we could design a suit with a lift coefficient comparable to that of the best STOL aircraft wings (a little over 3, with slats and flaps) we'd still need a forward speed around 70mph with a 15sq.ft area suit and a 200lb exit weight.

Seems to me that drag reduction is the way to go. That 200lb exit weight jumper at a GR of 3:1 is still producing some 60 - 70 pounds of drag force. To get a GR around 6:1 we would need to reduce drag to around 30lb force. I don't see this as being impossible with an integrated suit/rig, clean design at the wing roots and tips, and a decently shaped helmet.


rehmwa  (D 12816)

Dec 5, 2011, 12:51 PM
Post #20 of 65 (1909 views)
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Re: [kallend] Glide Ratios? [In reply to] Can't Post

really?- seems the trick is doing that with a less than rigid design


kallend  (D 23151)

Dec 5, 2011, 12:59 PM
Post #21 of 65 (1906 views)
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Re: [rehmwa] Glide Ratios? [In reply to] Can't Post

In reply to:
really?- seems the trick is doing that with a less than rigid design

If it were easy, someone would have done it already.


bertusgeert  (A License)

Dec 5, 2011, 1:19 PM
Post #22 of 65 (1897 views)
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Re: [kallend] Glide Ratios? [In reply to] Can't Post

In reply to:
In reply to:
really?- seems the trick is doing that with a less than rigid design

If it were easy, someone would have done it already.

The discussion I was having was with a top hang gliding pilot. Seeing what they do to reduce drag & profile size (wing and harness) is quite amazing. Just from looking at wingsuits & even hanggliders, seems that there is a ton of surface drag (vs. for instance composite, rivet-free aircraft). Don't know much about the phd level equations of all that, but seems that there's some work to do.


The111  (D 29246)

Dec 5, 2011, 4:04 PM
Post #23 of 65 (1873 views)
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Re: [bertusgeert] Glide Ratios? [In reply to] Can't Post

In reply to:
One day we'll ridge soar in wingsuit configuration. Or perhaps even have enough control over attitude to be able to fly slow & thermal, and then tuck & dive like birds of prey.

The "slow" will never come with a normal human body weight and the amount of wing we can support with our frame and muscles (the defining characteristic of a wingSUIT). Watch the fixed POV videos of a wingsuit flying by an object... it is not even remotely in the same ballpark as a bird or paraglider soaring slowly.

If some crazy new technology allows us to support a much larger wingspan, then yes it will be possible, but at that point I wouldn't call it a wingsuit, myself.

It is about like telling an elephant that with the right shoes, he can run along the top of a power line like a mouse.


KrisFlyZ  (C 34590)

Dec 5, 2011, 7:58 PM
Post #24 of 65 (1847 views)
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Re: [kallend] Glide Ratios? [In reply to] Can't Post

In reply to:
Seems to me that drag reduction is the way to go. That 200lb exit weight jumper at a GR of 3:1 is still producing some 60 - 70 pounds of drag force. To get a GR around 6:1 we would need to reduce drag to around 30lb force. I don't see this as being impossible with an integrated suit/rig, clean design at the wing roots and tips, and a decently shaped helmet.

Since the S3, wing suit L/Ds have only improved about 15%. There are already integrated rig suits out there, been out there for a year or two but nothing close to 3:1.

To double that is a tough ask.


kallend  (D 23151)

Dec 5, 2011, 8:15 PM
Post #25 of 65 (1842 views)
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Re: [KrisFlyZ] Glide Ratios? [In reply to] Can't Post

In reply to:
In reply to:
Seems to me that drag reduction is the way to go. That 200lb exit weight jumper at a GR of 3:1 is still producing some 60 - 70 pounds of drag force. To get a GR around 6:1 we would need to reduce drag to around 30lb force. I don't see this as being impossible with an integrated suit/rig, clean design at the wing roots and tips, and a decently shaped helmet.

Since the S3, wing suit L/Ds have only improved about 15%. There are already integrated rig suits out there, been out there for a year or two but nothing close to 3:1.

To double that is a tough ask.

ALL the sources of extra drag need to be addressed. I don't think we are anywhere near optimized in that area yet.


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