RCU Forums - View Single Post - using 2 - 3s lipos to power 12v starter?
Old 01-17-2013 | 11:03 AM
  #18  
da Rock
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Default RE: using 2 - 3s lipos to power 12v starter?

ORIGINAL: opjose


ORIGINAL: chadxp1

You could put a car tire between the starter and the cone and you will not get any more torque out of the starter.
Too bad you didn't read my actual post...

I said LEVERAGE.

The larger cone produces a bigger lever moment, resulting in more torque being applied to the engine, particularly if you have a spinner that can be gripped further out.

That is why I can easily start 55cc gassers with my Hobbico starter... a larger cone plus a 14.8v source.


Actually, leverage doesn't matter or make any difference to a starter driving a cone as far as the force transmitted to the engine is concerned. That is, it doesn't make any difference if the cone (of any diameter) grips the spinner or prop without slipping. No matter what diameter the grip is found, once gripped the starter is basically locked to the spinner until it slips. And how far the grip is from the axis of rotation means nothing.

The mass of the cone would have some effect once it was spun to speed. But once a cone and spinner grip, they are basically one piece, and the point of contact literally vanishes into theory.

The leverage would matter to how easily the cone might slip if too little effort was put into forcing the cone onto the spinner of course. But that's something else entirely.