Ovation with 310HP STC

[rbharvey]

Anyone know what the prefered cruise settings are? Is it 2550, 2600 or 2700 RPM. The STC has a 50 degree ROP power chart listing 2700 RPM as one of the MP and RPM combos yet the STC says max continuous is 2699. Curious what owners are using? I seem to remember 2550 but cannot seem to find it anywhere. Seems like an awful lot of money to spend for +50 RPM over standard cruise(not that it matters cause I already bought it ). I have always cruised my Moooneys at max RPM and WOT and than either LOP or ROP.

 

Thanks

[RobertoTohme]

Bob, I run my Eagle at 2,600 rpm, and I have charts for 2700, 2600 and 2550 rpm settings to determine MP at different altitudes and the corresponding fuel flow at ISA conditions; those charts were obtained from Midwest Mooney's website.

[rbharvey]

Thanks Roberto, I assume the Mooney pubilished speed gains are accomplished at 2700RPM, but cruising is not recommended there as per STC

Bob

[RobertoTohme]

Quote: rbharvey

Thanks Roberto, I assume the Mooney pubilished speed gains are accomplished at 2700RPM, but cruising is not recommended there as per STC

Bob

[docket]

I have the 310 STC in my Eagle and I usually cruise at 2550 and 23 on the Manifold at 9000.  I realistically see about 185 true at that altitude -- if I see more it is usually because I am fooling myself or the plane is low on fuel.  The interesting thing is that I don't pick up a lot extra speed at 2700 rpm and full throttle (maybe 3 knots) but the fuel burn goes way up.  Personally, I think the speed claims are a little optomistic but I do have Air Conditioning on mine so I am dragging that scoop on the bottom of the fuselage.  The only thing I can't quite figure out is why the Moritz Tach and the EI Tach never seem to agree how fast we are turning -- they disagree by as must as 200 RPM.  I usually take the average.

With the conversion my Eagle now runs smooth LOP so I usually run 50 LOP and see about 14.5 GPH and the engine temps are 320 degrees.   I could not run LOP before the conversion.  It also runs 17 GPH at 50 ROP so it follows the Midwest Mooney Chart pretty well.  When you give it ROP operation it does bring the engine temp up to about 340 degress.  I have found that you cannot decend LOP or you may get out of the green even at a constant manifold because there is not enough power being made.  Thus I usually descend ROP to keep the CHT constant.

I also think that I am making close to the right horsepower because the JPI shows nice even temps and the compression is so strong that when I shut down the compression brings the engine to a pretty quick and vibrating stop. 

I did make 300 knots over the ground coming back from San Angelo, Texas to Houston, Hobby in one of the recent cold fronts but the trip to San Angelo was 95 knots over the ground.  I will post the picture of the GPS in the Photo Gallery when I get a chance.

 

[KSMooniac]

I'll second Jim's recommendation on the RPM Sound application.  I've used it on my pocket pc smart phone and confirmed the accuracy with a hand-held optical tach.  Nice piece of software to have on hand, and you can't beat the price!