Winding

torqueburner
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Winding

Postby torqueburner » November 23rd, 2014, 7:05 am

A thread for discussion of winding technique. Just to get things started, here are a few thoughts:

Winding for maximum performance is something that goes way beyond just turning the handle on the winder. If you look back into the “Old Board 2001-2008” archives at the bottom of the “Forums” page, you can find discussion of many of the aspects of winding scattered throughout the Wright Stuff threads. (Also lots of info about other aspects of Wright Stuff here.)

For example, you will read that you should wind your motor to maximum torque and then back off to the desired launch torque. There is a nice discussion of the reason at the URL below. This starts out by describing the experiment and shows the data, but it is the plots and discussion that are really interesting. The upshot is that by winding to maximum and backing off, you will end up with more turns on your motor, and longer flights.

http://archive.today/l4DXn

Something else that is often recommended for winding is a torque meter. Rubber motors will vary slightly from loop to loop, and a given loop will stretch with repeated windings, thus requiring more turns to get to the same torque. For these reasons, torque is a more reliable gage of flight performance than turns. You can find plans, and information about the use of a torque meter by following the links below:

http://www.indoorspecialties.com/index1.html

http://www.modelflight.com/torque.html

The plans below are much simpler and easier to build, requiring no soldering, only some basic woodworking skills.

http://www.indoorduration.com/ftp/solde ... emeter.pdf

Recently I saw some torque meters for sale on ebay, so you may want to check there. You’ll see lots of other torque meters on ebay, so it is best to search for “rubber torque meter”, or something like that.

carneyf1d
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Re: Winding

Postby carneyf1d » December 16th, 2014, 12:13 pm

Anybody know of any good Tan Super Sport batches that have come out recently?

bjt4888
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Re: Winding

Postby bjt4888 » December 17th, 2014, 6:28 pm

CarneyF1D,
A couple of the national caliber adult indoor flyers that i am aware of have done testing recently on Tan SS and the general consensus is the batches from 2013 onward are all very good. I have some particularly good test results with November 2013. One test sample of this vintage matched torque specs (winding and unwinding) with 2/99 Tan II. Most reports that I've read are mentioning that tan ss is capable of very high torque for a particular rubber cross section. My tests on .090" (.061g/in) 11/2013 is that the breaking torque of a 2 gram motor is between 1.7 and 1.9 inch ounces. Of course, my students are flying in a category I site and are winding to about 80% max torque and backing off quite a bit.

That being said, it is probably best to focus on matching rubber motor thickness and length to best suit the propeller you are using to achieve top performance instead of searching for best rubber vintages (or, if you have time, do both). If you have time, test a variety of propeller styles and pitches with a variety of rubber motor thickness and length to see what gives you the best duration.

I see the "F1D" in your ID and am thinking that you already know about the above. Sorry if I am over-sharing.

Brian T.
AMA since 1972 (off and on)

28builder
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Re: Rubber motor not

Postby 28builder » December 18th, 2014, 7:48 am

does anybody know if ca glue can be dabbed on or near the knot of the rubber motor ?? the kids have tied what seemed to be a very good knot and it has slipped out a couple times. when wound around 1500 times or so....i always thought ca glue would melt or burn the rubber..any thoughts or suggestions..would double knotting work or aome other glue

carneyf1d
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Re: Winding

Postby carneyf1d » December 18th, 2014, 8:57 am

Thanks, BJT! I've been out of the indoor community for a little while and just starting to get back into it when my old high school asked me to give them tips for Wright Stuff. Used to build some F1D, ornithopter, ministick, pennyplane, etc. Back when I was flying the Tan SS was nothing compared to Tan II. Glad to hear that the new stuff is matching 2/99 quality! Now if I can only get my hands on a Wilder Winder...


28builder, I've always used two overhand knots when I tie my motors. Seems to work pretty well and haven't had it slip yet.
An even better way to tie your knots... https://books.google.com/books?id=cYlBT ... ts&f=false
And this comes from the book that is pretty much the bible of flying indoor duration planes.

28builder
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Re: Winding

Postby 28builder » December 18th, 2014, 9:34 am

thanks!

torqueburner
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Re: Rubber motor not

Postby torqueburner » December 18th, 2014, 9:36 am

does anybody know if ca glue can be dabbed on or near the knot of the rubber motor ?? the kids have tied what seemed to be a very good knot and it has slipped out a couple times. when wound around 1500 times or so....i always thought ca glue would melt or burn the rubber..any thoughts or suggestions..would double knotting work or aome other glue
I'll add this to what carneyf1d already said. We tie double square knots, one after the other. One important thing, IMHO, is that once you have tied the first knot, moisten it (saliva works well, and is always at hand:), and then pull the knot really tight. Follow up with another square knot, moisten and tighten. We have never had a knot come loose using this method.

jander14indoor
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Re: Winding

Postby jander14indoor » December 18th, 2014, 10:14 am

I like the double overhand knots myself, never had it slip, even lubricated. I wouldn't use CA as it is likely to damage the motor.

How I tie the double overhand knot. Since we are limited to 2.0 gm max and you don't want to be flying on 1.9 gm or have huge tails on your knot that don't contribute to flight time I do the following.
Weigh the motor and O-rings, unlubed or lubed and wiped down, to 1.98 gm or so.
Tie an overhand knot with the tails even. Don't worry to much about where, but close to end of tails is nice.
Now some magic happens, you'll have to trust me that this works, some lube or saliva helps this. Pull the loop ends of the knot apart slowly and watch the knot roll over itself and the tails get shorter. Stop when the tails are about 1/16 to 1/8 inch, preferably even, but definitely the shortest one should be in that range.
Now, if you've tied a lot over overhand knots like me, you don't think about what direction you twist the strand. Think about how you normally tie a knot, and most likely tied the first knot. Now, reverse it and tie it inside, NOT on top of the first knot. There should be a gap, but don't make it huge.
Now, magic again. Pull the loop ends apart again and walk the second knot up to the first.
Some more magic. As easy as it was to move a single knot, you CANNOT get the second knot to slip past the first and the first doesn't slip. Once locked together I've never seen this knot slip.

This discussion has that description illustrated! http://www.hippocketaeronautics.com/hpa ... pic=3650.0
or here: http://www.endlesslift.com/2011/10/ama- ... ter-class/
or here: http://www.endlesslift.com/2010/11/maki ... ber-motor/

Probably enough illustrations

Jeff Anderson
Livonia, MI

torqueburner
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Re: Winding

Postby torqueburner » December 23rd, 2014, 8:23 am

I like the double overhand knots myself. . .
Now some magic happens. . .Pull the loop ends apart again and walk the second knot up to the first.
Thanks for this, Jeff. I had heard of this technique, but I learned to use square knots and they never slipped, so we were happy. But this is definitely better, as you don't have to estimate how much extra mass to leave for the pigtails you cut off at the end. And of course, any technique that utilizes magic is a good thing! :)

Dave D.

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Re: Winding

Postby Yatswscwpollwe » December 24th, 2014, 2:36 pm

A great exchange of information.


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