Carl, thanks for all that great "rubber stuff" , I'll use every bit of it!
Your right about Dick O. After a couple of years of me picking his brains I
could get close to his EZB time.......................then he would reach
into his bag of tricks & kick my butt. He was a great guy. Thanks again for
the tips.
Ed
-------Original Message-------
From: Carl Bakay
Date: 2/28/2011 6:30:57 PM
To: Indoor_Construction_at_yahoogroups.com
Subject: Re: [Indoor_Construction] Re: Rubber Motor O rings
Ed,
There is no secret. Rubber that is "broken in" or pre-stretched, has more
energy than virgin rubber.
The evening before you are going to fly, loop your motor to 7 to 10 inches,
and stretch your motor between the doorknob and the top of the door in your
motel room, and let it sit for 5 minutes. Let it rest for 1 hour, and repeat
Let it rest overnight, and your motor will have much more energy. Some
times the loop will break, and this is a good thing, because it will not
break on the day of the meet. Make a habit of checking for cuts, splices,
and delaminations, as I said. The 0.42" inch strip is actually laminated
from two sheets of 0.021", originally designed for golf ball windings. Some
times it parts, but not often. Look edgewise, instead of flat-on, and you
might see it.
Another thing, get in the habit of winding motors until they break, the
night before, or the week before. All the time. This is 100%. Write it down
in terms of TPI, breaking turns per inch.
Then at the meet, you can wind to 95% of these turns with SOME confidence
that the motor will not break. Again, a broke-in motor will take more winds
than a virgin motor. We use the term TPI, or turns per inch. 100 to 110 TPI
is a good bench mark for starting. Thus a 12 inch loop will be good for 1200
to 1300 turns. A broken in motor may be safe at 1400 turns. This can be the
difference between 2nd and third place.
Values of foot pounds or specific numbers are not important, pre stretching
and preparation is.
Obarski was a champ. The best. He has caught that final thermal.
The idea is to prestretch it 7 to 8 times its original length, or until it
gets real tight. Also take some with you that you did not prestretch, and
you will see a difference. Keep it in poly bags and label them.
You mention procedure. Dick and all the rest of us kept notebooks. Buy a
spiral binder. Write down what you do. Keep a record. You can refer to it
from time to time.
Separate you rubber into so-so, good, and very good. Use the first two for
practice and testing, the last for contests. Other modellers may sell you
some of there good batches, as well. We are very friendly, and help each
other out.
Carl
From: Ed <ednlois_at_citcom.net>
To: Indoor_Construction_at_yahoogroups.com
Sent: Mon, February 28, 2011 3:14:30 PM
Subject: Re: [Indoor_Construction] Re: Rubber Motor O rings
Hello Carl, I've just joined the forum and found this email interesting.
When I first got into indoor it was in Tampa where I met Dick Obarski who
was an ole timer in indoor, you may have known him or heard of him. He took
me under his wing and became my mentor. He was in the middle of testing
rubber and was going through the stretching ( using a scale to measure
pounds of pull) as u stated. He would stretch a certain distance, measure ,
let the rubber rest then re-stretch at a greater distance and measure etc.
He would do this until he would come up with a value. However , this was so
long ago I forgot his procedure!!!
Ed Berton
-------Original Message-------
From: Carl Bakay
Date: 2/28/2011 2:02:51 PM
To: Indoor_Construction_at_yahoogroups.com
Subject: Re: [Indoor_Construction] Re: Rubber Motor O rings
I have done a lot of rubber testing thanks to Goldstein's prodding during my
INAV days, testing mostLy 7 inch loops of 1/8 strip, and without exception,
those that broke did so at the knot. These knots were un lubricated, due to
the difficulty of tying a lubed knot. The stye of the knot did not matter ..
It seemed that that was where all of the stress was located.
I wrapped my loops for stretch testing around a nail, over which was slid a
piece of Tygon fuel tubing. This also allowed the knot to move, in keeping
with current FAC technology for short rubber motors in multiple-engine
planes.
Carl Bakay
Sent from my iPad
On Feb 28, 2011, at 12:46 PM, "dennisatyson" <ddtyson_at_peoplepc.com> wrote:
Here is another source for 90A durometer o-rings at a great price.
http://www.oringsandmore.com/servlet/StoreFront
--- In Indoor_Construction_at_yahoogroups.com, Warthodson_at_... wrote:
>
>
> From what I have read & experienced, o-rings cut from plastic tubing do
not cut into the rubber any more than the wire hooks. It seems counter
intuitive, but many very experienced indoor flyers use plastic tubing for
o-rings. Personally, I prefer the hard plastic o-ring to a rubber o-ring. I
find them easier to hook up. I read somewhere that someone boiled their
plastic o-rings to remove the sharp edges, but I have never met anyone that
told me they actually do that. If the sharp edge were cutting into the
rubber I would expect most of my motors to break at the o-ring, but again
that has not been my experience.
> Gary
>
>
>
>
>
>
> -----Original Message-----
> From: Terry <jantel98_at_...>
> To: Indoor_Construction_at_yahoogroups.com
> Sent: Mon, Feb 28, 2011 7:05 am
> Subject: [Indoor_Construction] Rubber Motor O rings
>
>
>
>
> What are people using for O rings ?, I have heard of rigid plastic being
used, if so do it not cut into and damage the rubber ?, I have just cut some
thing rings from a light plastic (Ear cleaner) tube and was looking for a
way to smooth them down a little
>
> Terry
>
- application/x-ygp-stripped attachment: stored
- application/x-ygp-stripped attachment: stored
Received on Wed Mar 02 2011 - 05:35:57 CET