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yuri_base

The Mystery Of Hanwags, or How To Fly Phantom at 2.9

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Yo!

So I fly my Phantom from a balloon the other day, and as soon as I start to fly, I feel something is not right... it's too quiet! It was quietness and smoothness of the air I've never experienced before. I even looked quickly at both arms as if suspecting that I grew feathers on them.

There were no feathers, and I wasn't in heaven, but it definitely felt so. I was f l y i n g . . . :)

I examined the data, corrected it for the wind (GPS was turned on during the accent, effectively sampling winds aloft), and was astounded to find that the average L/D ratio during the best 20s of the flight was 2.9. WOW!!! (my best L/D in Phantom so far was 2.2-2.3)

How is that possible?! What was different on this flight?

Usually, I fly in sneakers, heavy skydiving rig and with a relatively heavy top-mounted camera. This time, I flew in heavy Hanwag boots (+4lbs) with a lighter rig (-10lbs) and no camera (-3.5lbs). Could it be that the shifted center of gravity put the body in optimally balanced position for the best glide?

The data shows unusually low forward speed (90-100mph vs. my usual 115) and ridiculous (for a 205-210lbs. meatbomb) fall rate – about 30mph (vs. usual 50). That’s why it felt soooo quiet! Those best 20s consumed only 1000ft of altitude, while covering 3000ft horizontally.

This discovery by accident lead me to thinking that in our quest to find that perfect body position and best wingsuit design we forget one of the most important factors: balance. Balance between aerodynamic forces and weight determines overall attitude of the flying body and its ability to glide efficiently.

By changing body position, we are able to change the balance somewhat, but we may still be far from that perfect balance. We may need to move our center of gravity using weights (as heavy boots and lighter rig did in my case).

Take canopies, for example. By shifting your weight under the wing (pulling on rear or front risers), you change the angle of attack. The best glide is usually achieved by giving some input to rear risers, that is, at rather high angle of attack. Small angle of attack (front risers) increases speed, but the glide ratio suffers.

It seems that we try to find the best glide with wingsuits by flying them on 'front risers' (actually, bending in the hips is probably equivalent to pulling both the front risers and the brakes). We always hear that speed is your best friend, that you need to go head low to achieve the best glide. But we might be looking for best L/D in the wrong place. If further experiments prove my theory, the best glide can be achieved by proper balancing and the resulting 'subterminal' - amazingly smooth and quiet - flight, not by going 'superterminal'.

Or is it all just some magic power of Hanwags?... ;)

Yuri


PS. Notes about data:

- GPS used: Etrex Vista C mounted on top of the helmet with a foam pad covering the breathing hole
- wind speed/direction were approximated using 4th order polynomials, which were used to calculate the corrected wingsuit speed
- I was flying downwind, but the wind is subtracted (as a vector) from the end result (L/D and true airspeed)
- fall rate was calculated as the loss of altitude in 5s divided by 5 (to smooth the noisy data)
- L/D was calculated as the horizontal distance (corrected for the wind) covered in 9s (centered at current point) divided by the loss of altitude in 9s (again, to smooth the data)
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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well...
hmm.
a mystery indeed,
I bet if you were actualy getting a 2,9/1 reading from GPS calculations, its probably not from the different equipment. definatly not weight.
Weight is a good freind for inefficient gliders, to an extent, i bet the lighter weight rig idint help in weight, but i would suppose it helped with airflow profile.
When I jump LEGALY from an airplane useing a single parachute system, i can track better, and fly longer than i can with skydiving gear.

In my GPS experience (hardly any skydiving, but i have used them A LOT in other applications) they are EXTREMELY inaccurate judging Altitude. i could explain this in depth but it would take a few paragraphs and im not in the mood.

Usualy, with my 3 GPS's i only buy ones with Aviation modifications, (pilot III, etc),those seem to have more reliable Antenaes. and i only buy one with a barometric sensor/altimeter. while also not accurate, it is better at finding an average sink speed than the GPS. keep in mind also, that GPS loses A LOT of accuracy with speed, at critical mach in an airliner its off by hundreds of meters.


just my dos pesos.

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keep in mind also, that GPS loses A LOT of accuracy with speed, at critical mach in an airliner its off by hundreds of meters.



I guess that explains why they don't use them in precision guided munitions...OH wait.:P

Since you seem to have extra time being laid up, PM me if you would like some good GPS resources to check out.
"It's just skydiving..additional drama is not required"
Some people dream about flying, I live my dream
SKYMONKEY PUBLISHING

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wait... i thought that the good ol' gov puts a cute little anti-accurate thing in the signal, and turns it off when they use killingpeople stuff that has it.

maybe im wrong, but when im flying at 18,000' in the kingair, it has a lot of trouble keeping up.

or did the good ol' gov turn that cute little virus thing off while i was in a coma?

seriously, did they?

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Now THAT is interesting...
Because you're the first bird I've seen report this phenomenon and when I noticed it I wrote it off as an illusion created by my inexperience at the time. This was about 3 years ago, long before I'd learned how to REALLY use my GTI, and quite awhile before I knew how to get 3 minute flights...I had under 50 WS flights total. I was wearing a pair of monster Caterpillar Steeltoe boots maybe 3 pounds each, and felt exactly what you describe, but I was wearing them because I wanted to extend my toes further than sneakers allow and the bulky boots really filled out the suit booties to the fullest. I stopped using them figuring with all that weight they probably cost as much glide as they gained in surface area and worked on learning other ways to get more freefall time.
Now I'm definitely going to try them again with the perspective gained by several more years of flying suit and see what happens. If it suddenly makes it much easier to manage a 3-minute flight despite the added weight, it'll be useful flight knowledge indeed.
Hearing someone else say this has me kicking myself in the ass for dropping what might have been a VERY productive line of research if I'd stayed with it.
Although I wonder if maybe the reason you got the result you did isn't the other way around and not the balance but the fact that you were truly stretching the suit to its fullest with the bulk? I'd say what we need to do is try the bulk without the weight... I'll see if I can get some clownishly oversized sneakers and try for the same longer-toes effect without the weight and balance changes. If heavy boots do it but oversized toes alone do not, we'll have solid data.
Has anyone else tried this? I discontinued the big boots long before I'd accumulated enough flight experience to know for sure or have any real basis for comparison... I remember thinking I flew much better with them on, but that impression flew in the face of everything senior pilots said, so I gave it up.
Anyone?
Live and learn... or die, and teach by example.

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wait... i thought that the good ol' gov puts a cute little anti-accurate thing in the signal, and turns it off when they use killingpeople stuff that has it.

maybe im wrong, but when im flying at 18,000' in the kingair, it has a lot of trouble keeping up.

or did the good ol' gov turn that cute little virus thing off while i was in a coma?

seriously, did they?



"Selective availability" was turned off in 2000.
"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

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I wonder if maybe the reason you got the result you did isn't the other way around and not the balance but the fact that you were truly stretching the suit to its fullest with the bulk? I'd say what we need to do is try the bulk without the weight... I'll see if I can get some clownishly oversized sneakers and try for the same longer-toes effect without the weight and balance changes. If heavy boots do it but oversized toes alone do not, we'll have solid data.



Brian, you f#@king natural bird... You're a mistake of Mother Nature. You should be shaving feathers instead of facial hair every morning...

Definitely try the balance thing. When you glide at 4.0, I'll send some cute Russian Chicks your way so we can start the Darwin's 'procreation for natural selection of the best species' thing.

Yuri ;)
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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Yuri, you know me so you can easily imagine the size of my grin right now.
Russian Chicks....mmmmmm......
I'm bouncing up and down right now, all excited cause I can't wait to get back in the air and try big boots again... I knew it felt right, I knew it! I shouldn't have walked away from that, I did and I regret it. Intuition was trying to tell me something and I failed to listen. I'm listening now.
ARGH!
I think you're right about the balance, too. I still want to try big silly lightweight sneakers to compare against but since I already have the boots I'll try them first and see. Last time I was still so new at flying I didn't really know what I was feeling, this time I have hundreds of flights and can make my GTI sing and dance if I want to so when I hit the air with the old boots back on, the difference should be instantly obvious to me.
WOOHOO!
Thanks Yuri, I think you just gave me back a set of keys I tossed aside a long time ago and shouldn't have. YEAH!
Live and learn... or die, and teach by example.

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Ankle weights and regular shoes,

or lightweight clown shoes? :D

And of course, according to the scientific method, it must be predictably repeatable by Yuribase as well as others.
"The evil of the world is made possible by nothing but the sanction you give it. " -John Galt from Atlas Shrugged, 1957

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Of course!
Thank you, thats the missing piece!
3 things to try then.
Bring back the megaboots everyone teased me about,
Try big big silly sneakers,
Then try my usual normal shoes with a couple pounds on each ankle.
One or more of those 3 keys will make my flights further and longer with no extra effort.
Funny. Some people think its all about "number chasing." Its not about the numbers, they're just measure. Its about Flying more.
I already have an RW weight belt with a bunch of little weights so that'll be easy to try, too, just a couple pounds and some duct tape. This might be better than boots and ought to help isolate the factors that created that sense of "feels right." Is it the added mass? The added suitstretch area? Both? Neither? Its occurred to me it might be entirely the mass and stretching the suit may actually be counterproductive. I know it is when I try too hard with my armwings... I just did 2 dives recently comparing "feel" again with totally different "wide" techniques to kind of re-verify to myself what I think I've learned... One where I flew pressing down hard on the armwings in the classical maxed-out mode, (142 seconds, 13.5-3000) and one where I didn't "press" at all and just sort of laid down got wicked wide and relaxed... (170 seconds, 13.9-3000 and damn near overshot the DZ in the process)

:)I'll post results to this thread when I've tried the various combos in a systematic fashion starting with the boots cause thats where I left off this line of experimentation.
Live and learn... or die, and teach by example.

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Brian, if the heavy shoes made a Behemoth fly at almost 3.0... I can only imagine what some lead soles can do to a Mosquito! :D

Dude, this quiteness of the air is AMAZING!!! :)

Maybe we'll do some flocking at 5.0 wearing beer bottles on our legs and do all the chicks om the 10 mile radius to spread some awesome L/D around... ;)

Yuri
Android+Wear/iOS/Windows apps:
L/D Vario, Smart Altimeter, Rockdrop Pro, Wingsuit FAP
iOS only: L/D Magic
Windows only: WS Studio

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Yuri, its also occurred to me it might be neither mass nor balance, exactly, but trim. If I'm using the term correctly.
Adding the boots makes your toes longer. Thus pulling the entire suit, body, wings and all, a little further down on your body relative to your center of mass. The suit fits different then, a little tighter across the tops of the shoulders, collar is pulled lower on the neck and forced open a bit more, top of the zipper might be half an inch lower relative to collarbones than it usually is and the trailing edges of the wings are a bit further back than normal, thus paradoxically shifting your weight forward.
The clown shoes will give the answer. If the clown shoes do better than weights or boots, there we have it, its suit fit making the difference.
Live and learn... or die, and teach by example.

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That is interesting. I am not sure mere 4 lb shoes would make a difference in balance...for someone weighing 40-50 times heavier. Also that should surely depend on how the body weight is distributed.


Kris.
P.S: What do I need to do to get cute russian chicks?



Try balancing horizontally on a bar set perpendicular to your body, and then have someone put a 4 pound weight on your feet and see if it upsets your balance.
...

The only sure way to survive a canopy collision is not to have one.

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That is interesting. I am not sure mere 4 lb shoes would make a difference in balance...for someone weighing 40-50 times heavier. Also that should surely depend on how the body weight is distributed.


Kris.
P.S: What do I need to do to get cute russian chicks?



Try balancing horizontally on a bar set perpendicular to your body, and then have someone put a 4 pound weight on your feet and see if it upsets your balance.



But there is no bar while flying on air is there? Its more like an infinate number of tiny bars all over the surface area of the body.

Kris.

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But there is no bar while flying on air is there? Its more like an infinate number of tiny bars all over the surface area of the body.

Kris.



There is a bar in the air. Every flying, lift generating body has a center of mass. In regular airplanes you want this to be some point in the wings. If you lift a model airplane by pointing 2 fingers upwards and lifting it by the wings, the center of mass is where the plane balances.

Anyways, I assume the same is true for wingsuits, but I'm no aeronautics engineer. I just remember having to adjust the balance on a model airplane I built as a kid.

Wikipedia has a thing or two to say about it. Apparently it does not really add to L/D ratios, but more to stall recovery and general stability of the plane.

Cheers
Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

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I have tried some of these experiments myself. With my old Classic I got the best times and covered more distance in big shoes, thick shirts and jeans, the suit was a bit wide for me! Filling out the suit gave me much better flights, but I got my custom GTi (tight fit) at about 40 wingsuit flights and like you, stopped trying these clothing experiments and learned to fly. :)
I have also flown my V-1 and GTi with a weight belt, up to 16lbs, and found that I had to work a lot harder with my arms but my forward speed was noticeably higher and I covered a bit more distance. Adding weights was much easier on the GTi.

Edited to add: I never tried the big shoes/clothes and weight combination.

Hope these bits help. Keep thinking and trying new things guys! I would be very interested to hear how your tests are run and your results. B|

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Ahhhhhh........my whole point was if 4lbs would have much affect.

Just try it....balancing on a pole perpendicular to the body is hard. While balancing in the air is easy. All I am saying is that flying in a wingsuit is closer to sleeping in a hammock than balancing on a pole. Also, we are not dealing with the entire body weight while wingsuiting If anything more weight would be needed to tip the balance while wingsuiting.

The real point of the question is if the conclusion reached is accurate. Yes, 2.9 is an awesome Glide but take it in context. It is in a segment of a flight. What was the average glide for the whole flight? Since this is a balloon flight, average L/D (wind corrected) can be compared to BASE jumps. My bet is that the 2.5 GR flight thats people are getting will have a segment where the L/D is significantly higher.

Just look at Han-solos tracking GPS log....1 average glide last 200-300m was 1.5 average glide. So 2.9 seems about right. Too many things changed on this flight to be able to say with certainity that it was the shoes and the balance.


Kris.

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All I am saying is that flying in a wingsuit is closer to sleeping in a hammock than balancing on a pole.



Yeah, that's true. When I think about it some more, the center of gravity story really only applies to airplanes with only 2 wings and an elevator. Wingsuits are different creatures of course.

Is the increased speed when wearing a lead belt not coming due to higher wingloading? Just like a swooper wearing lead to get more speed out of a particular canopy?
Costyn van Dongen - http://www.flylikebrick.com/ - World Wide Wingsuit News

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But there is no bar while flying on air is there? Its more like an infinate number of tiny bars all over the surface area of the body.

Kris.



There is a bar in the air. Every flying, lift generating body has a center of mass. In regular airplanes you want this to be some point in the wings. If you lift a model airplane by pointing 2 fingers upwards and lifting it by the wings, the center of mass is where the plane balances.

Anyways, I assume the same is true for wingsuits, but I'm no aeronautics engineer. I just remember having to adjust the balance on a model airplane I built as a kid.

Wikipedia has a thing or two to say about it. Apparently it does not really add to L/D ratios, but more to stall recovery and general stability of the plane.

Cheers



If you change the position of the center of mass you change the trim, and if you change the trim you change the performance. Maximum glide performance in a glider is usually obtained with the most rearward C of M you can get away with before running into stability problems.

My airplane has a 7 inch range of permitted C of M between max forward (flare becomes difficult) and max rear (potential instabilty). That's in a 2500 pound airplane. I imagine the range is far less in a human size flying machine. On an average person, adding 4 pounds to the feet will move the C of M back about an inch.
...

The only sure way to survive a canopy collision is not to have one.

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