carusoam Posted July 18, 2011 Report Posted July 18, 2011 http://www.mooneyspace.com/index.cfm?mainaction=posts&forumid=1&threadid=3034#post35198 A similar (current) discussion of Set-up, CHTs and FF in a Missile with an IO-550. Best regards, -a- For your consideration, I read the interesting info pointed out by Jorgen above. From TCM link given by Jorgen above.... IO-550-G (Ovation) idle rpm: 600 max rpm: 2500 FF gph: 21.3 - 22.1 (see original reference for pump and nozzle pressure ranges) IO-550-N idle rpm: 600 max rpm: 2700 FF gph: 25.6 - 27.3 (see original reference for pump and nozzle pressure ranges, keep in mind, this is TCM not midwest mooney) according to Deakin, it is better to be a little over than significantly under, regarding FF, CHT and cylinder life / valve cooling These specific details as I have written them are from online web research. Your milage may vary. Please consult a proffesional before using any of my posted details in your engine. (not that anyone would ruin a $50,000 engine based on something they read online). Quote
Shadrach Posted July 18, 2011 Report Posted July 18, 2011 Quote: Cris Ghovey- You got it right. The rpm's drive the cht temps all else being equal. I had a short flight Thurs. on an 85 D day at 100' elevation. RPM was 2690 & fuel flow was 32 GPH with the cyl temp at 402 D thru 2000'. You really need the higher fuel flow at max operating rpm. I don't recall the climb rate but I'll go back & confirm the figures for you when next I fly. This was a real issue at the MAPA PPI I last attended but I do not recall why it was so important to have the higher fuel flows. I seem to remember it is vital for cooling at ROP as well as getting the full performance but there was something else I'll have to check my notes.. I get similar performance as you in terms of CYL LOP at the reduced RPM's & I suspect that Ovation owners in genenal do also. "a " you want to chime in on this? Quote
ghovey Posted July 19, 2011 Report Posted July 19, 2011 Thanks for all of the info. Regarding EGT on climbout, it does not seem to be a problem as EGT continue to decrease unless you lean to increase them, while CHT will only decrease when %of power is sufficiently reduced due to alitude. Quote
Shadrach Posted July 19, 2011 Report Posted July 19, 2011 Why was EGT on climb out a problem? CHT can indeed decrease or increase at a constant power setting... It's why we lean or don't lean depending on the senario. All other things being equal, the power difference between 275 ROP and 100ROP is minimal, but the CHTs differences can be significant... Quote
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