RC plane propeller question - RC Groups
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Feb 04, 2004, 12:28 PM
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RC plane propeller question

Maybe you guys can help me.

I have a Yellow Bee electric flyer with two pusher motors on it. I changed the polarity on the port motor so that it would counter-rotate to the starboard engine. Of course that is when I found out the hard way that props have "handedness", i.e. props come in left and right handed versions (apparently). Do you carry props that can be purchased as either left or right handed? I would order one of each, since I can't figure out which is which for the current props I have for the aircraft.

Hoping you guys can help me or direct me to some manufacturer that can. Feel free to send me email too, kdwoell@comcast.net

Kirk Woellert
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Feb 04, 2004, 01:51 PM
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This site doesn't really "carry" anything. It's a discussion forum.

FYI most full-scale twin airplanes have engines that rotate in the same direction, clockwise as viewed from the pilot's seat. Your model was designed to have both motors running in the same direciton; I'd fly it that way.

Props are generally referred to in terms of "tractor" and "pusher." Pusher props are generally only necessary on internal combustion engines where it is not easy to reverse the rotation of the engine. It's usually a matter of swapping two wires on an electric motor to make it reverse, so we commonly use tractor props even if the motor is in a pusher configuration. Tractor props are more popular and more common, so there is a wider selection of sizes. Pusher props are rarer, and available in a limited set of sizes. Finding a matched pair of props, one tractor, and one pusher, is even more difficult.

I must admit that I have never heard of a "Yellow Bee" airplane. This is probably a prepackaged all-in-one setup, and probably has custom propellers. To pick the correct pair of propellers for your counter-rotating engines, you need to know the diameter and pitch of the propellers that came on it. This might be marked on the propeller, or specified in the instructions. If it isn't, you're pretty much SOL.
Feb 04, 2004, 03:29 PM
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BigDave's Avatar
Some brushed motors are designed to rotate in one direction only. The brush holders are "sprung" in such a manner that IF you reverse rotation, the brushes will wear much faster.

The question is still a good one, indeed, some multi-engine full scale twins have conter-rotating props to avoid some of the nasty P-factor problems when operating single-engine. As I recall, the Beechcraft Dutchess and the Piper Seneca were a couple of them.

You may have to resort to gas engine props to find matching CW and CCW rotating blades.

Good question, I have mulled it over also but did not fine suitable pops to try it out on a RC electric (yet).
Feb 05, 2004, 09:08 AM
Registered User
Andy W's Avatar
It's unlikely that you'll find what you're looking for. There are a few manufacturers who provide reverse props (also known as "pusher props" as glow engines only turn in one direction, so they are needed for those applications) but they only carry a few sizes, nothing in "parkflyer" size.
Feb 05, 2004, 07:53 PM
Registered User
Ok, I get it.

I currently have a CW pusher on the port side (as viewed from the aft of the plane), the motor turns clockwise. So what I need is a CCW pusher prop for the starboard side, (the side on which I reversed the polarity of the motor).

BTW, this particular plane is a ready-to-fly model. I posted this question, since the first time we flew, it veered to the left no matter what control inputs we gave it. This happened on subsequent test flights no matter how I ensured that the perforated control surfaces were zeroed up and that the only steering bias should be introduced by the differential speed of the motors. This model is very inexpensive (49$ for the whole kit). I reasoned that it was designed to fly in a big circle so that rudder and airelon servos are not required. The instructions say to adjust the v-rudder tabs to zero out any direction tendency, but that was never enough to make the plane fly relatively straight.