How to go from rpm to hp or W.

[boyongo]

Im trying to get the Hp or W for the O.S 61FX RC airplane motor that has a propeller size 13x6 that give 10400rpm. The reason for this is to know the max speed that it can obtain discarding the weight and everything.

 

[rcgldr]

The propeller has a 6 inch "pitch". At 10,400 rpm that translates into 86.67 feet / second or 59.1 mph in a no load situation. Actual max speed of the rc model will be much less.

 

[russ_watters]

Can't you look it up on OS's website? Calculating will be inexact...

 

[boyongo]

Just to be sure @ rcgldr we are talking about forward speed (velocity that the airplane is going to be traveling without any load and discarding the weight of the plane)?

 

[rcgldr]

Just to be sure @ rcgldr we are talking about forward speed (velocity that the airplane is going to be traveling without any load and discarding the weight of the plane)?

It would be better to say that if the plane were in a steep or vertical dive (and could achieve 59 mph speed with no power in a dive), that would be the speed where the prop would not experience a forward or backward load (only a torque load).