angle of attack, etc

[caspar 0]

i was wondering what everyone thought was the best body position for getting the best distance in tracking... post a diagram (easier to understand than explaining)

the pic i posted is the position i go for, seems to do me well, i was wondering if its actually any good? (i know, crappy pic but its the best i can do)

"When I read about the evils of drinking, I gave up reading."

[Elisha 1]

It may be good for you, but there could be something better. I'm told there is not a "one position fits all" for tracking, although what you show is kinda typical.

[pilatus_p 0]

Makes sense to me. You are mimicking what I would regard as a simple aerofoil, or wing section, much like you would find on a bird or older aircraft such as the wright brothers' machine.

I have little real world experience of tracking, but digging about in my aeronautics theory, heres my two cents / pennorth (depends where you come from):

The 'best' body position for lift will be the one with greatest curvature (better known as camber) that does not cause the air flow to break away from your body and become turbulent.

The best body position for distance will have minimum curvature, presenting least frontal area to the airflow, and hence provide least drag.

Of course if you change one, you impact the other.

If you speak to an aeronautical engineer he will tell you that wing design is primarily a battle of this trade off between drag and lift, and the best combination must be selected for what you want to achieve.

Cool post - I like the way you are thinking about it

Ross

http://www.teamtechnology.co.uk/troll.htm

[skytash 0]

The 'one-size-doesn't-fit-all' theory also makes sense to me, as the points at which different people can and do bend along the body-airfoil will vary with height and torso/leg proportion.

Something I've found helps in getting lift is to also cup the air with my chest by rolling my shoulders what would be forward if I'm upright (but ends up being down while tracking). It would be difficult to add that to your picture, however can also help in terms of the overall angle of attack from between head and toe.

tash

Don't ever save anything for a special occasion. Being alive is a special occasion. Avril Sloe

[Samurai136 0]

Quote

i was wondering what everyone thought was the best body position for getting the best distance in tracking... post a diagram (easier to understand than explaining)

the pic i posted is the position i go for, seems to do me well, i was wondering if its actually any good? (i know, crappy pic but its the best i can do)

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=2420468;search_string=tracking;#2420468

Take a look at the attached photos in this thread.

Your diagram looks to be a very head low tracking position.

"Buttons aren't toys." - Trillian
Ken

[hookitt 1]

Quote

Your diagram looks to be a very head low tracking position.

It HAS to be head low . Try it head high and you will not be going forward. :)

For the skier pictured, think of where the relative wind is coming from. If he continued to freefall, his body would begin to pitch downward just like the person in the sweet diagram in the caspar’s post.

That position is pretty much right on when wearing typical skydiving apparel. Trim it up a bit for your own body and away you go.

My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto

[pilatus_p 0]

Hehe this thread reminds me of this:

http://www.amazon.com/exec/obidos/ASIN/1891830368/pageturners0c

Might find this

http://amasci.com/wing/airfoil.html

interesting too ...

Ross

http://www.teamtechnology.co.uk/troll.htm

[kallend 2,115]

Quote

Makes sense to me. You are mimicking what I would regard as a simple aerofoil, or wing section, much like you would find on a bird or older aircraft such as the wright brothers' machine.

I have little real world experience of tracking, but digging about in my aeronautics theory, heres my two cents / pennorth (depends where you come from):

The 'best' body position for lift will be the one with greatest curvature (better known as camber) that does not cause the air flow to break away from your body and become turbulent.

The best body position for distance will have minimum curvature, presenting least frontal area to the airflow, and hence provide least drag.

Of course if you change one, you impact the other.

If you speak to an aeronautical engineer he will tell you that wing design is primarily a battle of this trade off between drag and lift, and the best combination must be selected for what you want to achieve.

Cool post - I like the way you are thinking about it

Ross

A human body in a track has an aspect ratio of around 0.25. At such low aspect ratios conventional "lifting line" wing theory is invalid. The mechanism of lift production has more to do with developing effective vortices. These also delay flow separation and the stall AoA can be extraordinarily high to the extent that a stall (in conventional sense) may never occur at all.

...

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

[kallend 2,115]

Quote

i was wondering what everyone thought was the best body position for getting the best distance in tracking... post a diagram (easier to understand than explaining)

the pic i posted is the position i go for, seems to do me well, i was wondering if its actually any good? (i know, crappy pic but its the best i can do)

A photo would be better. Lot's of people think they are dearched when they're not.

...

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

[pilatus_p 0]

OK OK I got my ass kicked by a professor.

But you did beat me to my post edit about the arguments in the community about lift theory, which lets be honest are raging all the time. http://amasci.com/wing/airfoil.html and http://amasci.com/wing/rotbal.html

Who knows, what with that Anderson guy kicking everyone's ass on the bernoulli theory of flight, he might just come along and kick yours, too ...



Only playing ... Glad to see you are pushing both the theoretical and humanist approach to skydiving - I see you have done a lot of work on it. What theory are you talking about? Circulation? Turbulence on top of the body? Coanda? I dont care if its geeky. Feed my brain.

Ross

http://www.teamtechnology.co.uk/troll.htm

[Samurai136 0]

Quote

It HAS to be head low . Try it head high and you will not be going forward. :)

Huh? The image the original poster provided is not an effective flat-track. If the head was any lower the figure would be in a good body position for being a late diver on a big-way.

"Buttons aren't toys." - Trillian
Ken

[ryoder 1,590]

Quote

A human body in a track has an aspect ratio of around 0.25. At such low aspect ratios conventional "lifting line" wing theory is invalid. The mechanism of lift production has more to do with developing effective vortices. These also delay flow separation and the stall AoA can be extraordinarily high to the extent that a stall (in conventional sense) may never occur at all.

I've seen some videos of BASE jumpers that track with their legs split wide and their arms in a delta almost touching their legs. At first I thought this was really weird, but then it occurred to me that they were increasing their aspect ratio, so maybe it was a good idea. I've experimented with using that position on a solo tracking dive. It works, but I didn't have any instrumentation to tell me if it was better or worse than the conventional ski-jumper style of track.

"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

[NWPoul 1]

Quote

I've seen some videos of BASE jumpers that track with their legs split wide and their arms in a delta almost touching their legs. At first I thought this was really weird, but then it occurred to me that they were increasing their aspect ratio, so maybe it was a good idea. I've experimented with using that position on a solo tracking dive. It works, but I didn't have any instrumentation to tell me if it was better or worse than the conventional ski-jumper style of track.

May be they do that more because of stability than AR
H-mm if you spread your arm like a bird (as Babylon guys did in trace 101 FF basik movie)
( >|o ) you'll get even more AR?
Or (If the AR so important) we should turn 90 degree and track by side of our body forward? this give us AR more than 3!

Why drink and drive, if you can smoke and fly?

[jakee 1,569]

Quote

I've seen some videos of BASE jumpers that track with their legs split wide and their arms in a delta almost touching their legs.

Isn't that mostly when using HP tracking suits like the PF suit and other homemade setups? It seems that they work best in those widespread positions but I was under the impression that thin 'spear' type body pos still works better for unaided tracking?

Do you want to have an ideagasm?

[sparkie 0]

Quote

the pic i posted is the position i go for, seems to do me well, i was wondering if its actually any good? (i know, crappy pic but its the best i can do)

Also: put your flaps to negative setting, less drag so mere distance covered/ft

[kallend 2,115]

Quote

Quote

the pic i posted is the position i go for, seems to do me well, i was wondering if its actually any good? (i know, crappy pic but its the best i can do)

Also: put your flaps to negative setting, less drag so mere distance covered/ft

You know this for a fact? How?

...

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

[78RATS 0]

skijumper


put a wingsuit on this guy and land that bitch.

Rat for Life - Fly till I die
When them stupid ass bitches ask why