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Old 07-27-2012, 02:56 AM
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mike109
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Default RE: Help with prop sizes and electric motors

G'day

I think you will find that E type props are lighter and thinner than Glo type props because glow engines give a big torque thump to the prop every second rotation for four strokes and every rotation for two strokes where as electric props give smaller torque thumps many times per rotation. As a result, the electric motor is "kinder" to the prop than an internal combustion (IC) engine is.

Electric props do tend to be very sharp but so do small IC props. The worst cut I have ever managed to give myself was with an APC 6 x 3 IC prop on a 0.8cc diesel engine. It took quite a chunk out of my finger which just brushed the end of the prop with the engine in full song. I suspect electric props will do this and better too.

The big thing with electric props is to not use one which is too large. The motor will try to turn it and draw excess current and may destroy its self and/or the ESC. I always test my motor/prop/ESC combinations with an inline AMP meter. The Turnigy 130 from HK works well and is quite cheap. I put on a prop that I think will do the job and measure its effect on the motor current draw and go smaller or larger depending on what I measure.

Cheers

Mike in Oz