The111 0 #1 January 27, 2007 Does weight affect glide? Does height affect glide? If your answer to either of the above is yes, please give a compelling reason.www.WingsuitPhotos.com Quote Share this post Link to post Share on other sites
jakee 1,255 #2 January 27, 2007 Quote Does weight affect glide? Just weight, or the effect excess weight can have on physique and body shape (Y'know, the 'built in arch')?Do you want to have an ideagasm? Quote Share this post Link to post Share on other sites
nathaniel 0 #3 January 27, 2007 Weight: Yes, greater force due to gravity, and implied aerodynamic effects based on volume / density constraints on the human body. Basically if your weight goes up your shape changes. Typically apple shaped for men, pear shaped for women, and depends on your individual anatomy. At the extremes it also affects your ability to fly, if you are morbidly obese or starved you may not have the strength to fly. Height: Yes, greater forces due to increased surface area, interactions with air, implied shape changes. We have an extremely complex system based on these factors as well as more direct measures of body shape, body position, strength, rigidity, planform, cross section, speed, air density, humidity, carried objects such as streamers, etc. In typical configurations some contribute more than others to the characteristics of your glide.My advice is to do what your parents did; get a job, sir. The bums will always lose. Do you hear me, Lebowski? Quote Share this post Link to post Share on other sites
SkymonkeyONE 3 #4 January 27, 2007 My only compelling example of it "not" affecting glide is Ryan Scarlett. He is MASSIVE (320 out the door), but simply kills it in his Phantom. He is incredibly fast, yet maintains all the lift he needs to stay up vertically with flocks. I don't know any other guys that big, other than "TallGuy" on here who can say that. Chuck Quote Share this post Link to post Share on other sites
MarkM 0 #5 January 28, 2007 Quote If your answer to either of the above is yes, please give a compelling reason. Otters get to altitude faster with fewer people in them. Quote Share this post Link to post Share on other sites
The111 0 #6 January 28, 2007 QuoteOtters get to altitude faster with fewer people in them. Argh, I just said this in another thread. SPEED does not equal GLIDE. Comparing a powered aircraft's climb rate at different loadings has nothing to do with glide. An unpowered Otter, with the same CG and different loadings, will glide at exactly the same slope.www.WingsuitPhotos.com Quote Share this post Link to post Share on other sites
KrisFlyZ 0 #7 January 28, 2007 QuoteQuoteOtters get to altitude faster with fewer people in them. Argh, I just said this in another thread. SPEED does not equal GLIDE. Comparing a powered aircraft's climb rate at different loadings has nothing to do with glide. An unpowered Otter, with the same CG and different loadings, will glide at exactly the same slope. No it won't...the Otter is also a crappy glider(phenomenal compared to humans but by glider standards..crappy). The gliders we talk about as gliding at the same glidescope but different speeds on increased weight are super efficient, super low drag flying objects. We are super inefficient wings(2:1) and we cannot convert that increased weight to lift as an efficient glider(70:1) would. There are also other implications in humans to increased weight that make the inefficiency even more(in most cases). http://en.wikipedia.org/wiki/Glider Kris. Quote Share this post Link to post Share on other sites
Macthe 0 #8 January 28, 2007 I'd like to say tall and thin will out glide the shorter and/or heavier dude, aria seems to be the controlling factor Tall with weight seems hot ie, 6'.2". 210 pounds ish super gliders use water as ballast to get more speed, funny, with all these experts we still dont know which is best Quote Share this post Link to post Share on other sites
nathaniel 0 #9 January 29, 2007 Quote SPEED does not equal GLIDE If you'd been clearer on what you meant at the outset... I suspect you meant GLIDE RATIO, or GLIDE PATH, not just GLIDE. Glide is a very general word. Speed does change your glide, "faster glide". But added speed may not change your glide path if the net added vector is in the same direction as the glide.My advice is to do what your parents did; get a job, sir. The bums will always lose. Do you hear me, Lebowski? Quote Share this post Link to post Share on other sites
Ghetto 0 #10 January 29, 2007 I think that the concept here is exactly the same as if we were talking about canopies. Its just wingloading we're speaking of (as far as the weight question goes). For example, if you take a sabre 120 loaded at 1.0 and a sabre 120 loaded at 1.4, they will have the same glide (assuming the higher loading doesnt cause the airfoil to distort.. just bear with me) So if you take two people of Exactly The Same Build and make one of them eat a bunch of super-small, super-dense marbles that adds 50lbs without changing their body shape (edit: and without changing their CG)... They should have the same glide slope. The dude with the marbles will fly faster horizontally, and faster vertically, and end up having a shorter flight, but will be able to fly on the same glide path. Its the same basic aerodynamics that we use when we refer to wingloading of canopies... If you keep the airfoil constant, and add weight, the glide remains the same but the speed increases. Anyone agree?Web Design Cleveland Skydiving "Hey, these cookies don't taste anything like girl scouts..." Quote Share this post Link to post Share on other sites
Ghetto 0 #11 January 29, 2007 QuoteNo it won't...the Otter is also a crappy glider(phenomenal compared to humans but by glider standards..crappy). The gliders we talk about as gliding at the same glidescope but different speeds on increased weight are super efficient, super low drag flying objects. We are super inefficient wings(2:1) and we cannot convert that increased weight to lift as an efficient glider(70:1) would. There are also other implications in humans to increased weight that make the inefficiency even more(in most cases). http://en.wikipedia.org/wiki/Glider Kris. Efficiency has nothing to do with whether or not weight will affect glide. The equation for glide slope is (as we all should know by now) Lift\Drag. Lift = Nothing to do with weight Drag = Nothing to do with weight Therefore, Lift\Drag = Nothing To Do With Weight. Glide = Lift\Drag. Period. If the airfoil, AoA, CG etc remains the same, lift and drag remain the same, and weight will not affect it. It will, however affect speed, handling, etc.Web Design Cleveland Skydiving "Hey, these cookies don't taste anything like girl scouts..." Quote Share this post Link to post Share on other sites
badenhop 0 #12 January 29, 2007 Quote with all these experts we still dont know which is best Yes we do. The answer is pink. Nothing to do with height, weight, width, mass, area, skill, fit.......================================== I've got all I need, Jesus and gravity. Dolly Parton http://www.AveryBadenhop.com Quote Share this post Link to post Share on other sites
Ghetto 0 #13 January 29, 2007 holy shit people i think he's right... the answer is pink! Web Design Cleveland Skydiving "Hey, these cookies don't taste anything like girl scouts..." Quote Share this post Link to post Share on other sites
KrisFlyZ 0 #14 January 29, 2007 O.k, bad example.... If we take humans...99+% stall flight. Drag will increase with velocity(square) but lift will not == poor glide with increased weight. Because more weight = more velocity. O.k honestly, I am just blabbering. Kris. Quote Share this post Link to post Share on other sites
Ghetto 0 #15 January 29, 2007 Quote99+% stall flight. is that for all flight modes or just for the slow-flight/stalled flight mode? QuoteO.k honestly, I am just blabbering. So am I... I'm just hoping somebody like Robi can step in and either agree with me or lay the smackety-down and shoot my theory to shit...Web Design Cleveland Skydiving "Hey, these cookies don't taste anything like girl scouts..." Quote Share this post Link to post Share on other sites
phoenixlpr 0 #16 January 29, 2007 QuoteEfficiency has nothing to do with whether or not weight will affect glide. The equation for glide slope is (as we all should know by now) Lift\Drag. Lift = Nothing to do with weight Drag = Nothing to do with weight Therefore, Lift\Drag = Nothing To Do With Weight. Smile That's interesting! more weight -> more speed more speed -> more drag speed is proportional to weight drag is proportional to the square of the speed Quote Share this post Link to post Share on other sites
The111 0 #17 January 29, 2007 QuoteIf you'd been clearer on what you meant at the outset... I suspect you meant GLIDE RATIO, or GLIDE PATH, not just GLIDE. Glide is a very general word. You are right Nathaniel, it would have been more clear if I'd said glide ratio. That is what I meant.www.WingsuitPhotos.com Quote Share this post Link to post Share on other sites
The111 0 #18 January 29, 2007 QuoteQuoteArgh, I just said this in another thread. SPEED does not equal GLIDE. Comparing a powered aircraft's climb rate at different loadings has nothing to do with glide. An unpowered Otter, with the same CG and different loadings, will glide at exactly the same slope. No it won't...the Otter is also a crappy glider. The gliders we talk about as gliding at the same glidescope but different speeds on increased weight are super efficient, super low drag flying objects. Yes, it will. This is a very fundamental aero principal. L/D depends on airframe, CG, and CoP, but NOT wing loading. This is not "only applicable to super gliders". I'm curious where you got that idea. Aerodynamics does not play favorites.www.WingsuitPhotos.com Quote Share this post Link to post Share on other sites
KrisFlyZ 0 #19 January 29, 2007 I am most likely wrong about the otter. I don't know where you got the idea of favourites. Why are you trying to apply the conditions that you stated, incorrectly(same shape and CG is impossible to achieve at different weights in humans) to humans? That is what I assume this thread is about. If not, I have nothing else to say. How much weight can someone gain before it changes their shape? 10kg? 20kg? 50kg? Does gaining weight change the shape for the better? Your argument that because it applies to airplanes..it applies to humans as well is wrong. Kris. Quote Share this post Link to post Share on other sites
The111 0 #20 January 29, 2007 I believe that for a given height (6'0"), for example, shape changes as a result of weight changes (a thicker body) have negligible effect on glide ratio. This is within a certain reasonable weight range. Obviously a 300-lb pear-shaped man will not fly very well. But put me versus somebody my same height and 30 lbs heavier (but still well-built), and I do not think either would be able to glide significantly flatter. We are deflecting air, for the most part. A great deal of drag is created by helmet, rig, hands, feet, etc. If you make the leading edges of the "airfoil" slightly thicker, it will not really be that big of a deal with all the inefficiencies we are already facing. Hell, it may even be a plus, if the leading edge is getting a little bit rounder. As far as height variance - no, aerodynamics does not scale perfectly. But on a +/-20% scale, when dealing with already poor gliders, I do not believe it makes as big of a deal as everyone assumes. Your ability to glide flat is determined much more by skill than it is by build, that is the main point I am trying to make. Weight and shape have much more pronounced effects on airspeed.www.WingsuitPhotos.com Quote Share this post Link to post Share on other sites
KrisFlyZ 0 #21 January 29, 2007 QuoteYour ability to glide flat is determined much more by skill than it is by build, that is the main point I am trying to make. Weight and shape have much more pronounced effects on airspeed. We were talking about how Cl and Cd are determined by nothing other than shape of the wing. If that is the case, how well someone can glide is only determined by their physical characteristics(wing properties). This discussion was about how Cl and Cd would change with weight and height. Where did skill come into the picture? What do you mean by skill? The ability to hold a certain angle? Aerodynamically speaking, the only thing(because other than the suit and rig we cannot change our physical characteristics...not instantaneously anyway*) that affects Lift and Drag and thus L/D is the Angle of Attack. What is the skill needed to stay still and hold an angle? For all people of the same height the person with the longer legs and shorter torso has the most area. Someone with long legs and short torso has an advantage because the balance of the suit(if the proper suit is chosen) and the bigger legwing naturally puts the flyer at an optimal AoA. Kris. Quote Share this post Link to post Share on other sites
nathaniel 0 #22 January 30, 2007 Quote I believe that for a given height (6'0"), for example, shape changes as a result of weight changes (a thicker body) have negligible effect on glide ratio. This is within a certain reasonable weight range. Obviously a 300-lb pear-shaped man will not fly very well. But put me versus somebody my same height and 30 lbs heavier (but still well-built), and I do not think either would be able to glide significantly flatter. There's a chapter 7 of this book that I think you would like very much. Go used, $52 is too much for this book. I got a copy at a bookfair for $6.My advice is to do what your parents did; get a job, sir. The bums will always lose. Do you hear me, Lebowski? Quote Share this post Link to post Share on other sites
KrisFlyZ 0 #23 February 1, 2007 Just got the book. Read Chapter 7. Very interesting. Kris. Quote Share this post Link to post Share on other sites
BlindBrick 0 #24 February 2, 2007 Quote Obviously a 300-lb pear-shaped man will not fly very well. Ask Chuck. I pretty much fit that description, but would like to think that, other than exits, I fly OK for a noob. -Blind"If you end up in an alligator's jaws, naked, you probably did something to deserve it." Quote Share this post Link to post Share on other sites
KrisFlyZ 0 #25 February 2, 2007 By fly this discussion means glide ratio(L/D). The discussion is also relative. How do you glide in comparision to someone of the same height but 130 lbs lighter? As humans we are programmed to compare. I have been speaking about average glide and not about steady state glide. This is more easily observed in real life. We can see who opened the farthest(and to some extent higher...from canopy time) much more easily than who has the best L/D. Assuming the weight and shape has no affect on L/D(steady state). In terms of average glide the much heavier people are at a disadvantage. It takes longer for them to get to their best gliding speeds(see Yuri's post on Fat vs Skinny and perceived performance). And due to their weight they also get to spend less time at their best L/D which screws up overall glide. As an example Flyer 1 : Skinny Exit altitude: 1000m Gets to best L/D of 2.5(50m/s fwd, 20m/s down) in 200m(altitude lost) has an L/D of 1 up to this point. Flyer 2 : Heavy Gets to best L/D of 2.5(75m/s fwd, 30m/s down) in 400m(altitude lost) has an L/D of 1 up to this point. For an opening altitude of 200m Flyer 1 can fly for a further 30 secs and his average glide is (200 + 50* 30)/800 = 2.125 Distance covered 1700m. Flyer 2 can fly for a further 10 secs and his average glide is (400 + 100* 10)/800 = 1.75 Distance covered 1400m. Quote Share this post Link to post Share on other sites
