On Thu, 15 Mar 2007, torqueburner wrote:
> I've been breaking in my loops by prewinding them before flying them,
> but I've heard that you can also break in the rubber by stretching it.
> Is there a reason to prefer one over the other? Can anyone suggest a
> procedure for the latter?
The motors for F1B wakefield are most often broken in be stretching, the
obvious reason for this is that motors with multiple strands wear quite a
lot when wound, stretching keeps the motors in better shape.
My break-in method for F1B is to stretch the motors almost to a certain
load, release, and immediately stretch to the load again. As motor breaks
in, the stretch need to be increased a little to keep the pull force
constant. Stretch for four minutes, then release.
The required force is a function of motor weight (naturally, but this is
constant for F1B motors) and stretch, so that thinner motors that stretch
longer need less force. The precise amount comes from a table calculated
by Bror Eimar, but roughtly I stretch motors with 26 strands of 1*3mm
rubber to 37 to 40 kiloponds. This is slightly less than 1.5 kilos per
strand. So if I had to break in a single loop of 1*2mm rubber, the easiest
way would be to hang a 2kg weight on the loop for 4 minutes...
Alas, I never need to break-in indoor rubber. Every now and then a strand
or know of my motors fail during the break-in or testing process. This
results in the motor to slipping, and the strands tend to cut into each
other. The result is 30 grams of rubber, that has some cuts in it so it is
useless for F1B (the cuts would fail while winding), but produces a number
of good motors for indoor. Especially, as I found out, you can cut rubber
that has been lubed with silicone, with no ill effects to the cutter.
-Tapio-
Received on Thu Mar 15 2007 - 05:43:26 CET
This archive was generated by Yannick on Sat Dec 14 2019 - 19:13:45 CET