Pull Force Required to Flare?

[azureriders 0]

Our friend Sue (Sectaerius), who is at work at the moment, has asked me to post this question for her.

Sue is currently a level 3 AFF student, with 9 jumps counting some tandems progression jumps, who plans to very soon come out of a several month lay off. She has had issues before where she felt insecure about having enough strength to flare properly. Now she is finishing up some physical therapy needed for a dislocated shoulder, which was the reason for her lay off. Her therapist has shown a lot of interest in simulating a skydive with her exercises, both to make sure her shoulder is up for the task and to help her with her prior strength concerns. For this simulation he needs to have an estimate of the required pull force to completely flare a canopy.

Sue is jumping 210ish F111 student canopies at approximately a .85 wing loading. I am sure everyone could make a guess at the pull force required to flare this, and we would be glad to hear those, but it would be really nice if anyone had any factual data or a link to similar information.

[councilman24 37]

I'll make my WAG, 15 lbs plus or minus 10lbs.

But of perhaps greater concern is dislocating the shoulder again in freefall. I've known of many situations where once it dislocated, the shoulder was prone to dislocating again. The pressure of freefall can do it. I knew one woman who had a shoulder routinely dislocate. She'd open, pop it back in and continue. But until back in it was pretty useless.

Have her talk to the Doc and therapist about pressure in various freefall positions. This may be a time where some time in a wind tunnel might be useful. A tandem would might do it but the exposure would be limited.

Not trying to scare anyone, but this is a real concern and probably more serious than the flare issue. And harder to simulate.

I'm old for my age.
Terry Urban
D-8631
FAA DPRE

[pilotdave 0]

http://www.skydivingmovies.com/ver2/pafiledb.php?action=file&id=254

Skydiver dislocates his shoulder on exit and someone else deploys for him... Bet the landing was no fun either.

Dave

[azureriders 0]

Quote

Have her talk to the Doc and therapist about pressure in various freefall positions

I am sure Sue can chime in here with more details, but to my understanding this has already been done

[waltappel 1]

Have you contacted canopy manufacturers?

Walt

[sectaerius 0]

Yes, I have talked to the Doc and therepist both about this and they seem to share the same opinion that once i finish the physical therepy and also the "strength training" that I will be fine. That is the reason I have been in pt for so long, to strengthen the muscles and everything surrounding the shoulder in hopes that it will not dislocate again. Naturally there are no guarantees that it wont happen, from either of them.

[apollard24 0]

I dislocated my shoulder during freefall in February. I spent 8 weeks in PT and was told I could return. I was told to continue my excercises at home to keep the strength in my shoulder. I have done about 25 jumps since the dislocation and everything is fine so far, but I am very careful not to push myself during jumps and stop when I know its time. Good luck in your recovery!


edit: as far as the flare force, I haven't had a hard time flaring but I am flying a smaller canopy..Maybe someone else will chime in with a response to your original question...

Breathe out so I can breathe you in...

[darkwing 5]

The quick, and not useful answer, is that it depends on the jumpers weight, and the specific canopy, among other things. I strongly recommend your friend work out some biomechanical strategies to help with her flare. Anxiety doesn't help, but ground practice does.

-- Jeff
My Skydiving History

[txskydiver 0]

Well it is not factual or similar canopy/wingloading...
however after coming back from a boken humerous and working out with varying amounts of weight, I can tell you that it is between 13-14 lbs to "flare" a 120 Sabre2 loaded at 1.4 using a rope over a simple pulley from Home Depot with simple free weights hanging off. We thought it would be about 12 lbs, so once I could pull that down I tried one jump and my injured arm could not pull through the transition between pulling and pushing (about 25 degrees above and below the 90 degree point at the elbow). To practice flare, we made the contraption hanging from a chin-up bar, the small dumbell weights we already had, 1/4" rope, 2 pulleys and cut up the wooden handle rope that the therapist had gives to pull your bad arm up with the good arm for stretches (it is made to fit on the top of a door). She should know what I am talking about. It was a little squeky sometimes, but it worked.

The important thing is that if she jumps and realizes she cannot pull down with her bad arm, then she can:
1. try to flare both sides with one arm (tried it and didn't feel confident) or
2. flare as far as she can and PLF - but make certain not to flare further with the good arm than she can with the bad one obviously. It is actually hard to fight the urge for the good arm to flare because it was habit for me and it just wanted to pull the toggle all the way down.
Hope it helps. Good luck to her on returning in good health.

[Programmer 0]

I didn't notice if you said how she dislocated the shoulder. That might not matter, but if her shoulder is prone to that sort of injury, it makes Councilman24's concern that much more serious. In my very limited experience, flare force can vary a lot depending on the type of canopy, trim, etc. One possibility would be a tandem jump where she tries a few practice flares up high with TM's help. If she can flare that thing, she can certainly flare whatever she's jumping solo.

[sectaerius 0]

First of all Thank you to everybody that posted here. The information is very much appreciated. I am open to anything anybody has to say on this as I am so new to this sport. Also, I dislocated my shoulder doing a tandem jump! I did not pick my feet up high enough so when we landed my feet hit first and threw us foward face down in the dirt and apparently all the impact was on my left shoulder.