It depends ...
Can anyone tell me if there is a sufficient performance difference in an O320 with a constant speed VS a fixed pitch prop (160hp). I realize there will be some difference but is there any emperical data showing the differences. I am trying to make the determination and if the top end is not significantly different I would be hard pressed to go with the higher priced, higher maintenance constant speed prop. I don't need to squeese out every bit of speed, just something reasonably close to the stated performance goals. Its time to order the finish kit!!!
I have flown the SAME RV6 with Sterba, MT and Catto (3-blade) fixed pitch props as well as Hartzell CS prop. I have also flown RV6A and RV9A with Sensenich FP and one of those RV9A's with Catto (3 blade).
With all of that I say it depends ...
The Sterba was most economical. Worked fine (have to slow down in rain though), was smooth. The MT and Catto gave better rain protection and each was dialed in for a slightly different RPM. For each of those props I was able to exceed 170kts true airspeed, given willingness to go wide open throttle. I tested them past 2800 RPM but afterwards never flew them that hard.
The weight with them all was a wash.
My acceleration was slow **compared to some RV's*** but it was just fine. My cruise was fine.
I changed to the CS for Formation Flying. (For the Team RV airshow group now, don't show up without one.
). Although my acceleration and deceleration is significantly better, my cruise speed is not significantly better.
There is more weight on the nose although in my case, with other changes, it amounted to about an additional 10 lbs I think.
Long-winded response to say her is MY opinion ....
1. Get a hollow crank engine for sure.
2. Start with an Ed Sterba if you want the "most economical".
3. Start with a Catto 3-blade if you want a nice, smooth, efficient prop and "3-blade sex appeal".
4. Start with a Sensenich if you want the benefits of metal (don't be bothered by the 2600 RPM restriction as I have had planes OUTRUN ME(!!) with those props as they really are tuned to the RVs.)
5. When you have a lot of additional $$ to spend or MUST do formation big time or need MORE climb performance, swap out the FP (sell it) and bolt on the $CS$ + some other $$tuff.
James