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I was looking at a video recently of a couple jumps I made. one was with a regular pin base rig and the other was one is longer and has more of an aerodynamic profile. my body position looked identical for both jumps. however, for the longer more profiled rig, there a noticable improvement in the track. i wouldn't have guessed it would have been so significant.

Can you share what model they were?

the blocky one is an overstuffed old Perigee Pro. the slimlined one is a Gravity Sports Vision.

Interesting. I have a Gravity Sports Vision and I'd say it's less aerodynamic (almost pillow-like) than any Perigee Pro I've seen. Perhaps it has to do with the canopy volume inside, I suppose?

You think it may have been from diferences in the turbulent boundary layer surrounding your body?

Look at any plane form wing cross section - the rounder the top (or the further the wind has to travel) the higher the lift. What really messes us up is our heads. Best to leave those on the ground.

NickD
BASE 194

Sill the body creates the most of the lift. And therefor the shape of the body is very important.
Most rigs today make the body as aerodynamic as a brick.. Some have understood the importance of a good profile over hte body, and started making more aerodynamic rigs. And belive me, you will fell the difference in speed and thus lift, if you have a smooth profile. To make wingsuits with better prifiles, airfoils etc, is to start in the wrong end. Start with the body/ rig and then think of the suits..

Take care

i have a hard time believing that a profiled rig is whats helping that much, i doubt that a video can compare the body positioning between two seperate tracks, the inputs of hte body is so minimal. im not trying to say your wrong, just saying that it beats me.

Hopefully some people can explain the theories on wingsuit crafting a little more. I've heard of airfoils in the wingsuits, and that it improves performance, but I don't understand how? I figure lift is not a good thing.

I thought that horizontal speed was caused by having more surface area on one side of your center of gravity and that drove you in the direction opposite the most surface area. And that with increased vertical speed your horizontal speed increased.

It seems that if you had lift, when your horizontal speed got high enough the lift would actually slow the vertical speed from transitioning to horizontal speed and your horizontal momentum would die down until you either dipped head down to pick up more vertical speed or stalled and ended up subterminal again.

There is probably more to this that I don't understand. Anyone care to share their ideas and or physical facts.

basic aerodynamic theory:

stick any plank out into the wind, and it will deflect air. the deflected air will impose a force on the object. (think of a rigid newbie just learning to track...)

the above is crude, but effective.

wings use airfoils, which create pressure differences between the upper and lower surfaces far more efficiently than a plank. they can look like an extended teardrop, or have one flat side (lower surface) and one curved side.

aerodynamically, lift is defined as a force generated perpendicular to the relative wind.

the most significant pressure differences between the upper and lower surfaces occur in the thick, first half of the airfoil. so, enhance this region and you'll have the greatest impact on generating lift.

so how does this apply to jumping?

well, in basic belly flying, jumpers are basically planks.

in freeflying, jumpers can act more like airfoils. thus the comment "don't arch" (it can create sidemays movement) and the atmomauti style of jumping.

while tracking, most jumpers continue to act as a plank to achieve horizontal separation. they angle their bodies to be head low and thus drop at an angle. but if a tracker adjusts the shape of their body to resemble an airfoil as much as possible, they can generate additional lift. this lift acts 90 degrees to the relative wind.

I have felt a force like a rope attached to my lower back just lifting me. this angled force will not only hold you up in the sky, but pull you horizontally. on big-ways, I specialize in base work. I'm built for that. but using this technique, I can track quite well. I actually must make ensure I don't track too well...

wingsuits use wings to add usable surface area to create more lift. at first, they looked like wings while a jumpers body resembled a fuselage. as wingsuits develop, the goal remains to make the entire body an airfoil. this would create the most lift. aviation buffs will recognize the term lifting body.

the norgies recognize that the first half of the airfoil generates the most lift. thus a smooth curve around the rig means more than a leg wing. (and if the rig distrupts the airflow, the leg wing will not reach it's potential...)

also, legwings and armwings can interfere with accessing sites for BASE jumping. think of climbing a ladder wearing a fancy wingsuit... by focusing on the rig, BASE jumpers can gain the benefits of lift while maintaining a full range of motion.

yes, I have simplified some of the concepts.
others with extensive wingsuit flying can add more.

hopefully this helps!

http://www.phoenix-fly.com/articles%20stvari/PF_Wingsuit%20flying%20and%20Basic%20Aerodynamics_1.pdf


read this ! I hope it is helpful!
Would be shame to not to get this knowledge while is there.

Thank you both.

clicky
http://www.phoenix-fly.com/...20Aerodynamics_1.pdf

The aim of a wingsuit is to get a good glide ratio. Glide ratio can be expressed as lift:drag. More lift for less drag = longer distance flight.

Why do you think gliders have wings instead of planks? Why do you think paragliders and parachutes have ram air airofoils instead of single skin surfaces?

I didn't realize that in our case lift is rarely up, but more of an angle of up and the direction you are heading. Before this I always thought that tracking was purely based on drag force.

Tom A sent me an awesome link that I learned a lot from. Especially the chunk on gliders.

http://www.grc.nasa.gov/...12/airplane/bga.html

Hello,

new aerodynamics rig works well. i got one and feel the difference. it's hard to say how much but i got this from www.adrenalinbase.com website, looks like VKB team use this equipment.
"Wind tunnel testing
Wind tunnel testing of the Adrenalin HYBRID rig compared to a “classic” rig design, as the ZAK, performed by VKB, summer 2006.

With the help of Hans Holmefjord, Oyvind Lokeberg performed as the test dummy, wearing two different suits (track suit & wingsuit). He got lots of data (lift, drag, glide ratio,…)

The setup with HYBRID rig showed lower drag in all tests of approximately 10-15 % compared to using the classic design. The reduced drag forces contributed to an overall better glide ratio, between 5 and 20%"