Re: Wind hard or not so hard?

From: Don Slusarczyk <don_at_slusarczyk.com>
Date: Mon, 18 Nov 2013 00:17:51 -0500

So you guys wind only to a torque and do not care about actual turn
count? I find that amazing. I am just the opposite, I go by turn count
then back off to a torque level to regulate the height. So If I want say
1750 launch turns on a motor that can take 2000 I may wind to1850 then
back off some turns to get my desired launch torque. If the motor could
take 2000 turns, I would not wind to 2000 then back off 250 to 1750. I
typically only wind (by turns) past my target minimum required launch
turns then back off some to knock off some of the torque. Also any new
motor I never fly use until broken in. I take a freshly made motor lube
it up generously then say if it would take 2000 turns I wind it to ~1750
or so then unwind and measure the length to see if it stretched, a 14":
loop would be like ~14.7" after a break in then I relube and then use
that for my flights. Once I do that process and the motor takes a
stretch set, the motor is rather consistent over the windings for the
day if you done push it too hard. The only time it starts to deviate is
if I really push the motor hard multiple times in a row. If I find my
model is needing near max turns on each flight and I wind to near max
turns on each flight and then say it hangs up, and then I wind max again
and hang again, then do it again I find the motor will sag and drop off
on these subsequent windings. So I then set that motor aside for a while
or make up a new one. Sometimes the "sagging" model will do equal time
from less height sometimes it does less time as the model will not climb
as high. I noticed this on Nocal a lot as the rules require 3 of 3
flights so often in a contest you take all three in a row and if you are
leaning on the motor the first flight, the second flight will be within
a few seconds but the third flight will always not climb as high and
will either so the same time or sometimes less so on the third flight I
usually do not back off as much as I know this will happen. I can
usually also tell it is sagging when I start to back off. A sagging
motor will drop torque quickly with a few unwinds which is something it
did not before. I may have needed 100 unwinds to get my torque but
after 3 or 4 full winds of the rubber only 50 backoff gets the same
torque then I know the motor is toasted for the day.

Don
>
> What Piecost and I are suggesting is to wind above launch torque then
> unwind, but not wind all the way to near breaking torque.
>
> For example, for a F1L flight at Urbana where the desired launch
> torque is 0.15 in-oz, wind to .35 in-oz, then back wind to 0.15 in-oz
> to launch. Do this instead of winding to the max torque of 0.45 or
> 0.5 in-oz, then back winding down to 0.15 in-oz.
>
>
Received on Sun Nov 17 2013 - 21:17:42 CET