I have Hartzell's efficiency analysis for their 3-blade and 2-blade props for the Legacy / IO550, if anyone's interested.  (I suspect that they would apply equally to any airframe and engine combination).

On Jan 25, 2013, at 1:32 PM, Bill Bradburry wrote:

Fred,

I have never been great at reading graphs, but the diagonal line is airspeed, not HP corrected for prop efficiency.  That is the vertical line. Or am I wrong??

How do you do this if you have an alternative engine and have no idea of what your HP is?  It seems that you are guessing about the prop efficiency and I would have to do the same for HP.  Perhaps if someone gets a FP drag number for the Lancair Legacy FG, I could work backwards and find the HP?

Bill