Thread: Mini-HowTo How to choose a power system
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Old Sep 25, 2007, 06:17 AM
aeajr is offline
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Quote:
Originally Posted by kzpl14
kinda yes but what did you do to figure out the amp draw for my battery. And what changes like if you have a 7.4v 1800 mah and then a 11.1v 1200 mah how will that effect the motor? Is the direct drive just the motor by itself with no gearbox? wont it burn up?
The amp draw is a function of the motor, the prop on the motor and the voltage applied to the motor. In your case, I just read it off the GWS charts at the links I posted.

Apparently you did NOT look at the GWS charts or you would have been able to answer the question about 7.4V vs 11.1V. I suggest you look at them.

The capacity of the battery pack has no relationship to the amp draw of the motor. Just as the size of the gas tank in your car has no relationship to the power of the engine. However the capacity of the battery does relate to the ability of the battery to deliver what the motor wants and, of course, how long the battery will last.

If you do not understand this, go back to the second page of the thread and read my post on sizing power systems. It is all covered there.
http://www.rcgroups.com/forums/showp...8&postcount=23

No, a direct drive motor will not burn up if you use an appropriate voltage battery pack and a properly sized prop. Direct drive is the way most planes are operated. All glow planes, that I have seen, are direct drive. Lots of RTF and ARF electric planes come as direct drive set-ups. And lots of after market motors are made to be used direct drive.

Just look at the GWS charts I provided for direct drive motors. That is why I have you links. Go study those charts till they make sense to you.

If you do not understand this, go back and read my post on sizing power systems. Direct drive vs. gearbox is discussed there.
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