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rameshkr
11-01-2010, 06:05 PM
hello everyone,

I am new to the RC plane word. How would I find out what size prop I need for what motor.

your help is greatly appreciated.

Regards,
Ramesh

MaxAdventure
11-01-2010, 06:37 PM
The easiest way when you have no background knowlege is find an existing power system that is the size (power, thrust, etc) you want and copy it. Find a similar plane (size/wing loading) look at it's motor, ESC, Prop, and battery and use the same or equivalent equipment.

The relationship of motor KV, amps, pitch are all a series of equations. If you want to learn the basics, there are some great sticky threads in the beginners section.

Otherwise your question is so open ended it's impossible to answer without knowing more details of what you want, what you are trying to do, what you have, etc.

slipstick
11-01-2010, 08:19 PM
Generally you choose a motor then look what size props the motor manufacturer recommends ;).

There are a few basics like high Kv, smaller prop, low Kv, larger prop but with motors out there ranging in power from a couple of watts (on 2-3" props) to several thousand watts (on 20-30" props) you'll need to ask slightly more definite questions.

Steve

Dr Kiwi
11-06-2010, 01:48 PM
Some good reading: http://www.rcgroups.com/forums/showthread.php?t=739069

z-8
11-13-2010, 02:12 PM
hello everyone,

I am new to the RC plane word. How would I find out what size prop I need for what motor.

your help is greatly appreciated.

Regards,
Ramesh

The link above is overly complex and, as usual, that means the person who wrote it doesn't understand very much about it. The best answer to your question is a question: how do you want your plane to fly? You can put any prop on any engine, the only difference is how it flies.

In the super-simple world of RC, you generally get to choose from fixed pitch props, so you must choose a single gear (directly analogous to a car transmission). If you choose "1st" gear, your plane could have a ton of power and huge acceleration, but a very low top speed. If you want very high top speed, you might choose "6th" gear and barely have enough thrust to takeoff.

So the simple answer is that all props work perfectly on all engines, they just accomplish different things.