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Old Jul 14, 2013, 04:20 PM
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Pasco Tri Cities, Washington, United States
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Converting my Cub

I have an ARF (Great Planes, I think) J3 Cub. It has an 80" wingspan, and is supposed to be flown with a .40 or .50 glow engine. I'd like to replace the slimmer 40 sized Super Tiger with an electric setup. What would make a good setup for motor, ESC and battery. I'd like to be able to buy one of the lesser cost units, if possible. I'd also like to be able to takeoff from both grass with it's wheels, and water on it's floats. I think I need something that has power similar to a strong 50 sized glow, or maybe even a 60 sized. Anyway, I have no idea what would give sufficient power to fly the Cub in a "scale-like" fashion--no hovering or thing like that. Just a nice flying Cub for Sunday flying.

Thoughts?

Larry
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Old Jul 14, 2013, 08:30 PM
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E-power for my Cub

One thing I left out of my first request (above) is acceptable prop sizes. After a bit of measuring, it appears that a 15 to 16" propeller will fit and clear the ground on takeoff and landings with the current gear and wheels.
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Old Jul 15, 2013, 04:32 AM
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Good call advising the prop size! If you can run a 15" prop, then Kv around 400 and 6S should do a good job - sure does in an 80" Hangar 9 Pawnee.

But before you decide on a motor, something else to consider is how much weight it's going to need up front to balance. For example, if it tends to tail heavy, The Eflite Power 60 at 380g would be a better choice than the Hacker A40 at 272g I run in the Pawnee. Both have nearly the same Kv and perform about the same, but getting the weight in the motor instead of ballast is often the best way to minimise overall weight.

Don't pay too much attention (in fact hardly any) to glow equivalent numbers in electric motor names, like the Power 60, as the outcome has nothing to do with the motor name and everything to do with the combination of Kv, voltage and prop size.

For example, if it was real tail heavy, you could go with a Power 110 on 8S for similar power to a Power 60 on 6S.

More generally, motors over 300g, combinations of cell count x Kv around 2400 and 15"or 16" props will do well , with the bigger motor, lower Kv, higher cell counts combinations probably delivering a bit better performance, but weighing a bit more.
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Old Jul 15, 2013, 07:55 AM
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Advice taken

Scirocco,
Thanks, that's exactly what kind of information I am looking for. It helps a lot.
Thanks Again,

Larry
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