On 7/21/04 2:19 PM, "Russell Duffy" <13brv3@bellsouth.net> wrote:

Since Tracy and I had the same static rpm with the previous props (which were the same made by Performance Prop), I expect I would have the same static he is getting if I had the 74" which I believe he indicated was around 6200 rpm or about 1000 rpm higher than with the old 2.14 and 68x72" prop.  That 1000 rpm increase will translate into approx 30HP more for take off and move the torque from 345 lb-ft to 455 lb-ft or a gain of approx 110 lb-ft torque for take off.  According to my spreadsheet that would move the take off HP from around 155 up to 185 for a standard day - in the cooler weather of all, it will be even more impressive.

 
Talking to Tracy about the difference between his B and C setups got me all excited again.  Sounds like he was REALLY happy with the performance difference.  

There's a fairly simple formula I saw once that converts excess HP to climb rate, given the weight of the plane.  Do you have that?  It would be interesting to see what 30 extra HP would do.  

Cheers,
Rusty (I need a runway)

Is it this one Rusty?
Bulent