Rubber motors

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Rubber motors

Postby baedman » Fri Oct 23, 2009 1:20 am

Useing a winding tube, how do I transfer the rubber after it is wound, from the S hook attached to the long wire hook and rubber, to the prop hook? I haven't tried it yet but wont the rubber be too tight, or do I leave the S hook on?
Bruce
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Postby SteveM » Fri Oct 23, 2009 12:55 pm

I've always left the rubber attached to the prop and hooked the winder into a metal loop that sticks out in front of the prop.

On this webpage you'll see the prop hook that is used for winding and can see that the rubber motor is well secured to the prop and not detached for winding. He doesn't show a picture of the winding, but does describe it in the text.
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Rubber motors

Postby baedman » Fri Oct 23, 2009 5:28 pm

Thanks Steve, why didn't I think of that? The web site you refered me to is excellent :!: I had already discovered it by goggling Esaki Yellow to see if that color would be approiate for my Piper Super Cub 95 that I am building. In fact I was reading the article, "Build your first flying scale Model", however I had stoped at the chapters on covering the fuselage and wings because thats where I am with my model.
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Re: Rubber motors

Postby kittyfritters » Mon Oct 26, 2009 1:05 pm

baedman wrote:Useing a winding tube, how do I transfer the rubber after it is wound, from the S hook attached to the long wire hook and rubber, to the prop hook? I haven't tried it yet but wont the rubber be too tight, or do I leave the S hook on?
Bruce


Man! Did you open up a whole can of worms with that question.

If you research old (and not so old) model magazines you will find that method of hooking the rubber to the prop have been a constant source of invention since the late 1920s. S-hooks, D-hooks, crochet hooks, sleeved hooks, all kinds of prop shaft ends, motor knots, motor binding, ad infinitum, have been tried to make the motor easier to handle, but insure that it will not come off or climb up the motor shaft. Rubber motor control is a big issue both at the front and rear of the motor, more for endurance models than scale models.

The idea is that the model will fly better if the motor is under complete control. I've tried it and can honestly say the my models fly better when I have paid this some attention. This means balancing the prop, and having the motor under control at both the front and rear ends so that when it's flying, it is so smooth and silent that people will ask if it's electric powered.

At the front I have had very good results with the GizmoGeezer front end assembly. This includes a screw type freewheel clutch, setscrew adjustable thrust bearing and a sleeved, ball joint motor connection. The screw type freewheel clutch has the advantage of keeping tension on the motor when it runs down to freewheel so that the balance of the plane does not change when the motor runs out. This does give away a few hundred turns, but gives a much better glide. It comes in three sizes 7, 8, and 9.5 inches, so if you need a different size you have to find something else.

I have also had good results with Peck prop shafts and D-hooks sleeved to the front of the motor (very carefully) with heat shrink tubing.

At the rear I have tried bobbins, roller bearings, and rocker bearings, and various types of motor binding from dental bands to heat shrink tubing. I have had mixed results from these, but have settled on 1/2 inch, plastic drapery tieback loops bound with dental bands. They provide good rear control and rocker bearing action and the large loop makes installing the motors very easy with a custom made pusher stick.

Then, there are some guys who just hook the motor over the rear peg, hook it onto the prop shaft and get great flights. As I said, you opened a whole can of worms (opinionwise) with that question.

(See http://www.gizmogeezer.com )

As far as transferring the motor from the winder to the prop shaft when using a blast tube, most people that I know use some kind of front end hook on the motor with a long wire hook that is longer than the blast tube. You either hook the long hook on the motor after winding or make one that fits between the winder and the motor, When finished winding, you simply slide the blast tube out of the model, up the long hook, unhook the motor and hook it onto the prop shaft. Of course, that is the critical moment. If you let go if it when it is unhooked...
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