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Rubber Motor Knots
Posted: March 18th, 2017, 10:56 am
by daydreamer0023
So I've been testing lately and it seems the knot that I've been using, which is the one recommended by FFM, is too fat and causing problems for the unwinding of the rubber in flight. :/
I was just curious as to what knots you all use for your motors and if there was a better one I could try.
Thanks in advance!
Re: Rubber Motor Knots
Posted: March 18th, 2017, 11:24 am
by JasperKota
I'm unfamiliar with helicopters, but basing off of wright stuff, the knot should not get caught on the body causing you to lose winds if you put the knot as close to the rear hook as possible. An alternative knot to the one from FFM (The overhand knot and square knot is what you're referring to I believe?) is just two overhand knots but both tied in different directions. More detailed description can be found in a post made by Jeff Anderson in this thread (Scroll down a little and you'll find it):
viewtopic.php?f=245&t=9271&start=60
Re: Rubber Motor Knots
Posted: September 2nd, 2017, 5:08 pm
by Cls413
I don't know if anyone else has had this problem, but the lubricant that I'm using is causing the knot to come undone during the flight. Do you all have any knots that work well to stop this from happening?
Re: Rubber Motor Knots
Posted: September 2nd, 2017, 7:25 pm
by JasperKota
Cls413 wrote:I don't know if anyone else has had this problem, but the lubricant that I'm using is causing the knot to come undone during the flight. Do you all have any knots that work well to stop this from happening?
Are you lubricating your rubber before tying the knot? I tie my knots with just water as a lubricant so the rubber doesn't cut into itself, and then lubricate with Armor All after. I've never had a problem with the knots being undone. The knot I use is this one:
Jeff Anderson wrote: - Lube the motor, at least the area where you'll tie the knot. Temporary lube is OK here, water works.
- I then make the ends even and tie an overhand knot, fairly near the end but no precise location.
- Then, grab both ends of the rubber on the inside of the loop near the knot and pull apart slowly. The knot will slip outward, making the tails shorter. Take that as close as you dare, I typically leave tails around 1/16 of an inch. Too short and this knot (which will become the outer knot) will sometimes slip. But that is surprisingly short.
- If the tails are too uneven, I keep pulling and pull the knot apart to start over.
- Now, here comes the magic.
-- Tie a second overhand knot inside the first, but in the opposite direction. I'm right handed and tie an overhand knot by spinning it clockwise around my left index finger. So to tie it the opposite direction I just stop and think and spin it counter clockwise around my left index finger.
-- Now, grab both ends of the rubber again on the inside of the loop and pull apart. This second know will slip outwards again, UNTIL it hits the first knot. It stops there and WON'T move. Ever. MANY years of flying, many years of coaching others, I've never had this double kn
ot slip in use, no glue needed.
Disclaimer: I haven't done Helicopters, but I assume tying rubber motors for Helicopters is very similar if not the same as Wright Stuff.