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Old 01-26-2010 | 12:02 PM
  #11  
jaka
 
Joined: Dec 2001
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From: Upplands Vasby, SWEDEN
Default RE: How to choose propeller?

Hi!
Of course not! They are not going to perform the same.
The only way you know what propeller to choose is by testing! By experience you will know what is best.

But there are some general rules. Rules that are unfortunately fairly blunt!
Large diameter and low pitch means lot's of low speed performance.
Small diameter and a little higher pitch means more speed.

Fort instance in international pylon racing where we use 6,5cc two stroke engines (F3D) and the models are 180cm in span and the speed is around 375km/h, we use 7x7,5" carbon props.

When using the same size engine however in a high winged trainer airplane like the Kyosho "Calmato (with a sport 6,5cc engine) flying at at sea level, the plane performs best using a 11x6 prop.
The same 6,5cc sport engine in a low winged 3D model used for hovering, then a 12x4 or 13,25x3,75 propeller gives best performance.