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Old Apr 03, 2007, 12:20 PM
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Southern Vermont
Joined Feb 2007
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I think the 4 x 2 sounds good. The 4x4 will draw more amps, and I kinda remember something about using a 7 amp ESC?

The higher pitches are mainly for increasing speed or wattage (power). Since the plane doesn't need much power or speed, doesn't seem to need a 4x4.

I'm still going to go with the 3x3, like you suggested. I'm totally curious about that. I did order some 4x2s too just to see what the difference is.

From what I read the other motor (G4046) is a higher Kv motor -- meaning the rpm per volt is higher, and is suitable mainly if you want a gear drive, not direct drive. So for this plane direct drive you want the DCM 189 aka Jameco 311976 aka 20519.

Take the following with a grain of gumbo file powder:

Motocalc says a 3x3 will draw under 4 amps with a 7 cell Nimh and 4.3 or so with 8 cells on this plane. It says the prop is stalled but will fly (wastefully).

It says a 4x2 prop will not be stalled, and will draw a little less than 7 amps on 7 cells and a little more on 8.

It says a 4x4 will be stalled and drawing around 9 amps. So it doesn't look like a really great combo, though all of them are apparently flying the plane.

Notes: The wattage goes up for each of the choices above in order. So the power delivered does as well.

I don't know whether the motor will heat up on the 4x4 -- this seems to vary according to the flyer.

The above is based on a 9-1/2 ounce AUW finished plane. I don't actually know what mine will be yet. It's a little over 3 ounces, bare airframe.
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Last edited by vtdiy; Apr 03, 2007 at 12:29 PM.
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