David Paule
Well Known Member
I'm repeating this here for broader distribution. Initially, I wrote it for someone's trip write-up.
For tiedown knots, ditch those "tent" knots that you're using, they won't hold up to a real blow. They'll slide up the rope and things will get sloppy and loose and the plane will start rocking and eventually something will break. Instead, use three half-hitches right at the tiedown rings after pulling the ropes just as tight as you can get them -- don't use chocks while doing this. I tie one main, then the other one, cranking down on it, and then the tail, pulling the plane back as I do for more tightness.
When the length of the ropes permit, I double-up the rope. The idea is to gain more stiffness. Anything to keep the plane from moving around. It's the dynamic movement of the plane which breaks things.
Also, if you have an idea where the winds will come from, it's best to orient the plane so that the wind comes from a front quarter. Directly nose into the wind seems to increase the loads on the ropes and rings, while aft winds can damage the control surfaces. Directly sideways is acceptable.
Of course you'll use your control locks.
I learned this after some 100+ mph winds at the Boulder Airport in 1981 or 1982. We lost about a dozen airplanes. I walked among the wreckage examining what failed, and among the survivors, examining what worked.
Dave
For tiedown knots, ditch those "tent" knots that you're using, they won't hold up to a real blow. They'll slide up the rope and things will get sloppy and loose and the plane will start rocking and eventually something will break. Instead, use three half-hitches right at the tiedown rings after pulling the ropes just as tight as you can get them -- don't use chocks while doing this. I tie one main, then the other one, cranking down on it, and then the tail, pulling the plane back as I do for more tightness.
When the length of the ropes permit, I double-up the rope. The idea is to gain more stiffness. Anything to keep the plane from moving around. It's the dynamic movement of the plane which breaks things.
Also, if you have an idea where the winds will come from, it's best to orient the plane so that the wind comes from a front quarter. Directly nose into the wind seems to increase the loads on the ropes and rings, while aft winds can damage the control surfaces. Directly sideways is acceptable.
Of course you'll use your control locks.
I learned this after some 100+ mph winds at the Boulder Airport in 1981 or 1982. We lost about a dozen airplanes. I walked among the wreckage examining what failed, and among the survivors, examining what worked.
Dave