Repitch Sensenich for XP-360

I have an RV6 swinging the Sensenich 72FM 85 inch pitch prop that Vans sells, turned by a Superior XP-360-B1AA2.

I've noted several people in the forum state that they can exceed 2700RPM when wide open throttle with this configuration - At 8500' I'm in the same boat.

Has anyone ever re-pitched this propeller to get more top end? Right now, I can run 24" /2400 RPM at 2000MSL, but only see 160MPH indicated. I'm thinking this should be higher.

After a quick call to Sensenich and some spreadsheet calcs, I'm contemplating an increase in pitch from 85 to 90". Has anyone repitched this prop that far? Were you happy with it?

Today I was climbing out at 1350fpm at 90MPH. I am willing to give up some of that performance if it gives me a top end closer to 180mph or better. Any thoughts?

Don

dtw_rv6 said:

Right now, I can run 24" /2400 RPM at 2000MSL, but only see 160MPH indicated. I'm thinking this should be higher.

Click to expand...

If you are able to run at 24" at 2000 MSL and only turn up to 2400 RPM, then more pitch will probably not be helpful.
That means you are already at a pitch that will absorb ~ 75% power down low but you are sub par for speed some what.

I would suspect that you probably have some drag issues that should be resolved before you start messing with prop pitch.

I have the exact same prop as you on an RV-6A with O-360-A1A. It is not super fast down low (just like you) but that is because I have to run at 21-22" to be at 2500 RPM or lower. Once I climb higher (9.5K - 11.5K) I can use more throttle and the IAS is still around 160 MPH but the TAS is about 190 MPH.

Another drawback to repitching is that the pitch change is not uniform on the entire blade. The pitch really only changes on the outer 2/3's of the blade so you loose a bit of efficency with teh change.

If you decide to take this prop off, I may be interested in buying it, if the price is right.

Thanks,
Tom