Hello,
I bought this motor in ebay some time ago:

and I would like to know what is the better propeller for a foamy of about 600g weight w/ motor included.
Someone has bought this same motor?
These are the specs:
-Rpm(Kv): 2900Rpm/V
-Resistance: 0.20
-Max Amps: 12
-Gear Rate: 5.5 : 1
-Weight: 62g
-Length: 31mm
-Diameter:20mm
-Shaft Diameter: 3.0mm
-Recommended Battery: 7.2, 8.4, 11.1 Volt Li-Polymer Battery
It also comes w/ an ESC which you can set brake on or off, but I don't know what is brake, can anyone explain this to me?
Thank you very much.

First you also have to know the gearing ratio to be able to figure out which prop you want to use.

And you also have to determine what type of flying you want to achieve.

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"Brake" is the ability of the ESC to produce a sort of reverse current in the motor, that brings it to an almost immediate stop.


This is often used in folding prop planes to get the folding prop to fold back quickly.

Note that on regular planes enabling the break can damage mounts and the firewall, as a great deal of torque is exerted.

You need to be particularly careful with electrics vis-a-vis starting and stopping torque because they produce their maximum torque INSTANTLY, unlike glow/gas planes.

On the NP support thread there was a post by someone who had ripped a brushless motor out of an Omnei glider and they cited this as a problem in the design.

Nope, the guy put on a strong brushless with a big prop on a small plane, and the effective torque of startup ripped the motor out!

Hello,
thank for the answer.
The gearing ratio is 5.5/1 and I want to achieve an acrobatic flight, the model is a corsair.
Greetings.

As in F4U Corsair? That's not exactly a plane that one would choose for doing aerobatics. I don't fly 3D but there are quite a few inexpensive foamie's that do exactly that. One that comes to mind is 'The Bug' at www.lightflite.com It's an odd looking thing but is really capable.

More is needed to know what prop you should use. Weight is a key factor. How much does that corsair weigh with engine, ESC, batteries, and servos installed?

CGr.

Yes it is a F4U, about the weight it is less more than 600g with all installed and ready to fly.

Just throwing some numbers around into a prop calculator...

An 11x7E prop will buy you about 88% efficiency and about 330watts in with about 21oz of static thrust using an 11v lipo battery.

You should be able to use a 900mAh battery to save weight and still get over 10 minutes in flight time.

You haven't stated what the motor's maximum wattage rating is... so I don't know if 330watts is a safe range maximum for your motor.