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baggettcpa

I'm New Here
I'm flying an RV8 with a Lycoming 0-360 engine and a Sensenich fixed pitch prop (the one made for the RV-8). At 8,000 to 10,000 feet, I can't use full throttle, as it will overspeed the engine (2700 max). I've taken it higher, and have to get to about 15,000 feet to use full throttle. At 8,000 feet and 2650 rpm, I cruise at about 163K TAS, but have considerable throttle left. It would seem to me that if I could get a prop that would max out at around 8,000 to 10,000 feet, I could get more power and a little more speed. Anyone have ideas on this?

Jud Baggett
 
Welcome to VAF!!!!

Hey Jud, welcome to the force.

Glad to see you aboard.

One possibility for your prop-----have it re-pitched. Check with some prop shops in your area???
 
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Compromises

Welcome to the party!

On the prop question, remember F/P props are always a compromise. I am guessing that you are getting around 2700 RPM on takeoff. If you pitch the prop to get 2700 at 10,000ft. and WOT, you will not get full take off RPM at sea level. Kirk is cracking wise, but he is right, that is why some of us elect to go to the trouble of having a C/S prop.

John Clark
RV8 N18U "Sunshine"
KSBA
 
Welcome, Jud.......

.......Yep, re-pitch......if your goal is max cruise speed. As a point of reference, my Catto is pitched for max cruise and it will go to 2750 at 7500' and yield 202 MPH/176K. However, the compromise is that we only get 2200 static on takeoff but still use less than 700' run. We wanted max cruise and Craig Catto delivered. No regrets.

Regards,
 
Im flying an 8A with the same setup. Started with the factory 85 and went to 88 repitch. Speed still under 190mph. The Prop will still go over 2700rpm. The max pitch for that prop is 89. Im in Texas hill county not much need for a lot of climb but still get 1500+ at 120knots. Hope this helps.

William Bennett
RV8A N643WB
 
Pierre, or any one else with a 180hp/Catto 3 blade combo. What RPM do you typically get WOT at higher altitudes, say 10K, 12, and higher? Are you using LOP techniques at these altitudes?
 
Don't know...

....since I've only gone to 8500 but it will still turn 2700 or slightly better WOT and leaned to just rich of peak EGT.

Regards
 
Pierre, thanks for the quick reply! Jud, sorry for the attempt to hijack your thread. Still working on my "netiquitte."
 
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