From: Tom Sanders
First, why the effort? Braiding motors keeps the rubber under tension minimizing the CG change during the flight from fore to aft. Motors unwind from the front and the remaining knots always crawl to the back of the bus.
Assume the motor will be a 24" loop (48" single strand) or longer.
MATERIALS: Rubber O-rings, FAI tan rubber strip, CA med vis glue, Dow Corning #33 med vis silicone lube and a good stuffer stick (to get the slimey mass into and anchored in the fuselage).
METHOD A: Slide your O-ring onto the strip and place at the midpoint. Now, this is very important, anchor that midpoint so it can't move or twist. It may be easier to loop a knot at the centerpoint O-ring and then clamp it down.
Take strand #1 and twist it** with you fingers (dry rubber is easiest) while counting until you get a full row of real knots. Clamp the end of strand #1 down so it can't unwind. Twisting is tedious, I know, but its worth it.
Take strand #2 and now twist it also the same way (same rotation) as strand #1.
When you have both twisted (seperately) you may now bring the ends together and put in your favorite knot.
To lock the knot, put a smidge of CA BEHIND the knot and scrunch it between your thumb and forefinger.
Take off your clamps, hold the motor at the knot and swing madly over your head like a cowboy with the "grip". After 5 seconds of swinging let the motor rest. Even up the braid by pulling it through your thumb and forefinger. Success! Looks cool don't it!
Liberally lube the new motor with Dow Corning Silicone Grease (#33) and stretch wind before storing.
METHOD B: the "Don Scrull method".... Basically the same as method A except that strand # 2 is rotated in the OPPOSITE direction. Finish as before. This time the motor will have odd, grapevine looking knots towards the centerpoint of the motor. Those odd forms are called "goobers" and naturally keep the rubber's mass away from the tail. Ugly, but effective!
VARIATION A: Add an additional O-ring to the back of the motor at the knot. O-rings should be just big enough for a single strip to fit through. Some folks get O-rings a little bigger to fit the fuselage pin. A bit tricky but it works.
Notes: You can get the rubber O-rings and grease from your local industrial supply house or contact the national outfits.... GRAINGER has offices all over, as does McMASTER-CARR. Their Chicago office phone is 630-833-0300.
Gummibanders are really twisted aren't they!
** - Bob Hunt offers...
You didn't mention the direction of the pre-winding. If wound opposite normal winding direction, motor will braid neatly, with little shortening of overall length. If wound the same as normal, the moter will spit out loops (goobers?) as it winds down, effectively shortening overall length thus maintaining C/G. Len Sherman says braiding causes some loss of power.(friction maybe?)
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