5th Control Line

[RayLosli 11]

" P.S. It must suck to stall that much on BASE jumps."
.

When the Flik came out I was pretty convinced that it would be widely accepted on the fact of the " Flair Stroke " being so similar to newer jumpers that were rally never raised on the larger 7-cell canopies as Skydivers. The extra line cascade is more sensitive to the pilots input on the controls. When you have more control of the amount of fabric at the tail section with input. I am seeing this as Big Plus. I am also seeing this as a big plus on doing Flat-Turns at lower AGL approach to land. Fliks are flat flyers with the capability of doing some very nice flat turns in the deep area of toggle control.
BUT I think that if you don't know your canopy and it's flight characteristics. When a BASE jumper gets himself into a tight situation and gets pressed with pressure. If he over reacts and 'Panic Stabs' the controls. Stall is just more likely to happen. And of course the canopy with 5 instead of 4 attachment points is going to be a little more touchy-feely with LESS movement and pull of the Toggles. Any Canopy that is taken to far and into the 'point of stall' with out the appropriate amount of forward speed to compensate. Is going to shudder and then If the Pilot get really overloaded he will pound himself in to the dirt. The same thing applies if you move this to the end of the spectrum. I don't know how many times I have heard people complain when starting out. That there canopy is not flaring right and there having hard landings.. Only to find that there control lines are to long or they are just not flaring deep enough on the stroke.
I have witnessed some very good accuracy from pilots using the 5th line. The size of you PC does make a difference on the distortion of the Flair on the pendulum when you are riding the Wire on the approach to make your final inputs with the control lines. Everything though must be taken into consideration how the design of the flight characteristics of that manufactures wing was intended to be controlled.
.

[d_goldsmith 1]

I jump a blackjack with 5 lines. I set the toggles on skydives and then ended up moving them up about an inch after BASE jumping it because I was coming in kind of hard. On skydiving I was using a tiny PC and most my BASE jumps are on a 42. But I've also used a 46 twice and didn't notice any difference at all. I've never stalled it and my flairs on both PC's give me very nice soft landings.

[fab777 0]

Quote

I don't see how a pull on the attachment point (in any direction) could cause a change in the angle of attack. Can you explain your reasoning?

Increase in drag without a change in lift. This moves your position on the polar curve of the wing. That is theory, and works IRL...

Fabien
BASE#944

[wwarped 0]

Quote

I don't see how a pull on the attachment point (in any direction) could cause a change in the angle of attack. Can you explain your reasoning?

angle of attack - the angular difference between the relative wind and the chord line

relative wind - you ought to know...

chord line - an imaginary line drawn between the tip and the tail of the airfoil

thus, deflecting the tail down causes the chord line to change it's angle. this results in a greater angle of attack.

DON'T PANIC
The lies in learning how to throw yourself at the ground and miss.
sloppy habits -> sloppy jumps -> injury or worse

[d_goldsmith 1]

The PC's inflating because it's being drug through the air, so the angle of attack is the angle that the PC's being towed. Since it's attached to the center of the canopy, I assume it would pull the center B lines back a bit, but I don't think it would change the angle of attack noticably.

I figure there's probably a lot more force on the suspension lines, keeping the canopy's shape and angle of attack togethor.

Consider when the PC is off to one side or another. If the force is strong enough to change the angle of attack, wouldn't that be like pulling down on a front and rear riser on the same side (maybe it is).

I'd love to hear more thoughts on this. Or referenced video if anyone has a good example.

[460 0]

Some of these statements in this thread make no sense at all. The PC can have a major role in the flight of the canopy, of course. This was one of the motivators for using sleeve technology to collapse the pilot chute.

Looks like a death sandwich without the bread - Steve Deadman Morrell, BASE 174

[d_goldsmith 1]

It sounds like your saying that the stall's are because a lack of forward speed? Do you think that the PC effects the trim noticably?

[jakee 1,254]

Quote

Since it's attached to the center of the canopy, I assume it would pull the center B lines back a bit, but I don't think it would change the angle of attack noticably.

I figure there's probably a lot more force on the suspension lines, keeping the canopy's shape and angle of attack together.

You do not need to change the shape of a canopy to change its angle of attack. In laymans terms, AoA is the degree to which the canopy is mushing through the air.

This is basic stuff...

Do you want to have an ideagasm?

[d_goldsmith 1]

I added the word shape in there because if someone thinks the PC pulls enough to change the angle of attack, it would pull the center of the canopy back and change the shape a bit.

[460 0]

Quote

It sounds like your saying that the stall's are because a lack of forward speed? Do you think that the PC effects the trim noticably?

exactly. you canopy flight and flare will be better if it does not have a pilot chute on it. be reminded though that the control stroke (i.e., pulling the toggles) will have to be much deeper than otherwise.

Enormous pilot chutes can actually distort a canopy causing a pronounced kink in the canopy as viewed from either above or below. It's a significant air anchor. It's more pronounced on 9 cell canopes.

Looks like a death sandwich without the bread - Steve Deadman Morrell, BASE 174

[wwarped 0]

Quote

The PC's inflating because it's being drug through the air, so the angle of attack is the angle that the PC's being towed.

NO!

while the PC is being dragged through the air, it is in disturbed air. there is no guaranteed relationship between the angle of the PC and the AoA.

to create the same amount of lift at slower speeds, the AoA must be increased. it it increases too much, a stall results.

as stated before, this is basic stuff.

and YES, the PC influences how the canopy flies. it just seems like you need to brush up on basic theory before adding that layer of complexity.

DON'T PANIC
The lies in learning how to throw yourself at the ground and miss.
sloppy habits -> sloppy jumps -> injury or worse