Originally Posted by
bogbeagle
I reckon that a good "scale" performance would need 10 hp ... at 1/2 scale.
I don't have a clue as to how much horse power is needed ...........
I tend to look at displacement rather than HP. HP ratings are obtained by engine manufacturers by using props which are inappropriate for our application to get the RPM's up which gets the HP rating up. For our application on high drag WW1 airframes torque at a lower rpm is more useful than horse power at a high rpm.
But the more displacement one has, generally speaking, the more horse power one also has (however much that might be).
I think I have enough with 120cc's for good "scale" performance.