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Old Oct 11, 2008, 03:42 PM
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Rock On- Damon Atwood
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Fishers, Indiana
Joined Oct 2004
6,213 Posts
Originally Posted by AmpAce

Just so you know, I haven't actually experimented with belt drives. What I stated in my last post is mostly heresay, imagination working overtime, and just what I've read.

It just seems logical that a belt driving a shaft would be less likely to set up a vibration between the motor and shaft, due to alignment imperfections, than would an end-on coupling of some sort.

As far as weight savings, I was thinking mainly about using brushless inrunners, of a smaller size than the Axi 4130. Some of the better ones are supposed to be quite a bit more efficient than any outrunner, and with the different sizing of sprockets available, could be geared to turn the scale props at whatever RPM needed to get the thrust. My thoughts are that you could probably also get by with smaller battery packs for the same power and duration.

As you noted, the belt drive system does give much more flexibility in locating the motors. Given the shape of the nacelles, though, you might not be able to get the motors quite as far forward with a belt drive, as with an end-on coupling, except where the wing tube is in the way.

Let us know how your tests of the two systems go!

Great project!

It is really funny, I was about 98% sure of what I was going to use for power, now after inputting some inrunner motors and gearing them 4-1 or 5-1 in ElectriCalc I can say that I am just about back to square one. To be scale I need a 18" 3 blade prop, when I look at gearing it is funny that my 100 power flying time would Calc out to about 3.9 minutes at 54mph, but pull the power back to 65% at 39mph and I get about 13 minutes, that is where I plan on fly at anyway. Thats with a smaller motor and gearing the prop. I have a lot to learn . But at least the parts can get cut out for now and a bunch of building can get done before I have to land on what power plant I am using.

Thanks a ton for your input.

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