Line stow force question

[lookoutbelow 0]

I was measuring the force required to extract the lines from my stows, and all were between 8-12 pounds except for the two locking stows. Those measured around 14 pounds. Everything I've read suggested we want 8-12 pounds on all stows. Should I consider trying to find a band combination for the locking stows to bring them down a few pounds, or is 14 good for them? Seems like it would ensure they are the last to pop, but I also don't know what force the pilot chute exerts and would hate to be on the edge of them not popping at all. Opinions?

[skydiverek 56]

You are good.

[lookoutbelow 0]

Thanks. Now I just need good weather and a day off, and for those to occur on the same day.

[rehmwa 2]

I think the PC snatch is pretty much good to go for +14 (but hopefully an rigger pipes in on that to be sure)

However, if you have more free time, you might take a large sample of bands configured to that 14 pound assumption and then see how many really are at that load. (i.e., what's the distribution if you check, say, 100, instead of just a couple, what's the max, what's the min)

then, if you have more time, you might try seeing how many openings it takes for that 14 pound number to decrease to that 8-12 level......

...
Driving is a one dimensional activity - a monkey can do it - being proud of your driving abilities is like being proud of being able to put on pants

[lookoutbelow 0]

Good points. My measurements are from a small sample set, and in this case, all were new bands. I might just have to keep a running log for a short period of time, for curiosity’s sake.

[JerryBaumchen 1,063]

Hi lookout,

Quote

the force required to extract the lines from my stows, and all were between 8-12 pounds except for the two locking stows. Those measured around 14 pounds.

Remember that the two locking stows are almost always holding the too-large canopy into the too-small d-bag.

It is usually very simply that the locking stows have more force imposed onto them than the line stows because of this.

If you look at the attached photo, you will see that the locking stows are stretched far more than most line stow rubber bands would be.

Does this opinion help any?

JerryBaumchen

[lookoutbelow 0]

Aye, makes sense. Thanks. I guess what I was primarily concerned with though was not so much that the locking stows were more than the others, but whether being over the recommended 12 pound maximum would be an issue when it came time for the pilot chute to yank the lines out. I am not too worried really as I assumed that the 12 pounds value might be a little conservative for safety, but I had no idea how much force a standard size pilot chute would exert. Ultimately I guess I just wanted some consensus that 14 pounds on those two stows wasn't pushing the edge beyond reasonable safety.

[wolfriverjoe 1,351]

#1 - A pilot chute has a lot more than 14# of pull.

#2 - My understanding (and I welcome correction from those who really know what they're talking about if I am wrong) is that the 8-12 is a balance between enough to hold it in place securely, but not too much to prevent it from deploying smoothly. More holdlng force would cause the D-bag to bounce around a lot (or a lot more than it does already). Which could cause issues well before being tight enough to cause a bag lock.

"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy

"~ya don't GET old by being weak & stupid!" - Airtwardo

[Skydivesg 6]

Just for the heck of it, check out this video.

It talks about using big bands and double stowing them from a well respected canopy company - PD.

While not perfectly on topic it will help give you some perspective.


http://www.youtube.com/watch?v=4Nsca5add8g&feature=BFa&list=PL45E3B7998E49283E&lf=plcp&context=C3ba9045FDOEgsToPDskKtwuSbBH6eBKT_rvwiaKOl&index=14

Be the canopy pilot you want that other guy to be.

[davidw 1]

Quote

Hi lookout,

Quote

the force required to extract the lines from my stows, and all were between 8-12 pounds except for the two locking stows. Those measured around 14 pounds.

Remember that the two locking stows are almost always holding the too-large canopy into the too-small d-bag.

It is usually very simply that the locking stows have more force imposed onto them than the line stows because of this.

If you look at the attached photo, you will see that the locking stows are stretched far more than most line stow rubber bands would be.

Does this opinion help any?

JerryBaumchen[/Don't forget the line group is thicker closer to the locking stows due to cascades/steering lines]

• Quote

[JerryBaumchen 1,063]

Hi david,

Quote

Don't forget the line group is thicker closer to the locking stows due to cascades/steering lines

Very good point.

I do not know if I forgot it or just did not think of it.

Now where are my car keys?



JerryBaumchen

[Mr.Bill 0]

I once took an old worn out pilot chute, wrapped the bridle around my hand, and while doing about 45 MPH on the way home pitched it out the window.
Thought it was going to take my arm off.
If you decide to try this start at no more than 35 MPH
Pilot chutes have a BUNCH of snatch force.

[craigbey 0]

Pilot chute snatch force thread...

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=3162292#3162292

Last post at bottom of thread has an attachment with PC drag data.