question about suitable prop and servo for a small speed boat
 

Hello.

Im building a small rc boat and i have most of the parts but there are a few questions i have. im trying to build a quick little boat that's fun to play with.

The hull is a 14" long deep v that is about 5" wide that is made it out of Styrofoam insulation that was hollowed out and fiber glassed. i have a tx/rx, a 30A watercooled esc, a 3" long aluminum rudder with water pickup, a set of turn fins, a flex shaft with a shaft sleeve, a 24.5mm water cooling motor sleve, and a racerstar 2430 8200kV brushless motor that i was gifted from a friends rc car that will run on a 2s 7.4v battery.

This brings me to my 2 main questions.
1. what would be an appropriate prop be for this motor to get this little boat moving quick on the water
2. how strong of a servo would i want to control the rudder?

any help would be greatly appreciated!

regards,
RCypher

At 60680 rpm, it will need to be very small and well balanced. You will probably need a gearbox to get the prop rpm down to a sensible level, when something like a 20mm prop will be viable. Or a lower KV motor.
A 3" rudder on a boat that small will be huge, at least a "standard" size servo.

That is a totally inappropriate motor for 2S, you will burn up your ESC and motor. You want a motor Kv between 3000 and 3500 rpm, the motor size you have is okay. Do you have water cooling? Try an Octura x427 prop.

As above, the rudder is needlessly long, you only need 1.5” in the water. No need for a standard size servo either, a decent mini or micro servo will work fine in that tiny boat.

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Hey! Thanks for the input!

I told my friend the motor wouldn't work for me and he happens to have a 370 brushless motor rated at 3300kv so I think I will give that a try instead and look for a 20mm prop as well as new rudder hardware and servo.

Thanks for the help!

Have any pictures?
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