brakes versus rear risers

[karel 0]

no wind or wind in your back - what gets you further, brakes or
rear risers ???
karel

[skycat 0]

I know this varies by canopy, but on my crossfire loaded 1.3:1 it is definately rear risers. Only time I float in brakes is if my arms get tired.

[TEB6363 0]

Un-stow the breaks and keep pressure on the rear risers. This will flatten your glide slope and give you the maximum distance per foot of descent. Remember to try this early and learn the stall characteristics of your canopy.

[billvon 2,998]

In zero winds, here are what works for me, in order of effectiveness:
1. Loosen your chest strap, kill your slider, and get it as low as possible. This lets your risers spread out, and that flattens your canopy, thus making it more efficient.
2. Spread your rear risers further with your hands. This pulls down the tail a little bit and flattens the canopy a bit further.
3. Use a little bit of brake, no more than 1/4. This will also extend your glide.
4. Pull your feet up and pull your legstraps down a little so you can sit "flatter" in the harness. This helps reduce wind resistance.
5. Pull your rear risers down, but not so much you get an obvious "step" in the canopy.
The more tail wind you have, the more rear risers/brakes will work. 1 2 and 4 work in any wind conditions, since they both increase your speed and your glide ratio.
-bill von

[skycat 0]

Also read this thread from swooping and canopy control.
here

[karel 0]

thanks Bill, that's a pretty comprehensive answer
is there any theoretical way of comparing changing angle of attack (risers) versus changing aerodynamic profile of wing(brakes)? I know it will vary for different canopies - just the theory behind it.
planes change wing profile for landing, do they also change
angle of attack?
karel

[billvon 2,998]

>is there any theoretical way of comparing changing angle of attack (risers) versus changing aerodynamic profile of wing(brakes)?
Well, it's not that clear-cut. If you had four risers on each side, you could conceivably change the actual angle of incidence. (That's what paragliders do, BTW.) With just two risers, you just add a "step function" to the center of the canopy, which gives you a somewhat different result. Neither rear risers nor brakes change the angle of incidence of the nose of the canopy, which is the angle between the canopy and the "fixed" part of the system (i.e. the skydiver.)
In both cases, however, the angle of attack _does_ change. Angle of attack is direction of relative wind compared to chord line of the canopy. If your L/D (lift over drag) ratio changes, your angle of attack does too, even if the canopy doesn't move at all. An example of this would be killing your slider and tightening up your body. Drag will decrease, the canopy will glide slighty flatter, and the air will come from a slightly flatter angle - thus the canopy's angle of attack will decrease.
So if whatever you do with your brakes/rear risers lets you glide farther, the angle of attack of your canopy is effectively decreasing.
Is that confusing enough? Adding to the problem is that a parachute is constantly adjusting itself, flexing and moving around above you to maintain its trim speed. This can screw some people up, because if they pull the toggles down, they feel a sudden lift. They can mistake this for greater L/D, when in fact it was only a momentary increase in lift, and the canopy will soon return to its trim glide - which now may be even worse because of the additional drag of the pulled down tail.
>planes change wing profile for landing, do they also change angle of attack?
Definitely yes. They both change their airfoil by mechanical means (leading edge devices, flaps) and increase their angle of attack by slowing the plane and raising the nose.
-bill von

[SkymonkeyONE 4]

This varies canopy to canopy. Some manufacturers will tell you this on their websites, but generally, it is something that I figure out for myself.
Chuck
My webpage HERE