rwabdu Posted June 6, 2023 Report Share Posted June 6, 2023 Yes, I’m basing that off the poh. Here is my performance at 5000. My Cis a 1968. The key number isn’t listed in my poh but makes a lot of sense. 6 hours ago, Hank said: Do you have Performance Tables inyour Owners Manual? I've attached mine for 5000 and 7500 msl. What year is your C? Mine is 1970. The Key Number for our engines is 46; add your MP and RPM, keep the total 46 or less. For example, I often use 22" / 2400 at 4000-7000 msl, which is below 75% and very leanable. Quote Link to comment Share on other sites More sharing options...
Hank Posted June 6, 2023 Report Share Posted June 6, 2023 @rwabdu, looks like 22"/2300, 22"/2400, amd 22"/2500 all all < 75%, so lean away. Quote Link to comment Share on other sites More sharing options...
FlySafe Posted June 6, 2023 Report Share Posted June 6, 2023 Hi All short-body flyers. Here are some recent savvy flight data from a cohort of 77, M20(A-D) for comparison to your personal numbers. Don't laugh or judge me for my lower power/TAS choices. Best wishes, k 20230305 Trend Analysis Report N7763M.pdf 1 1 Quote Link to comment Share on other sites More sharing options...
Jcmtl Posted June 7, 2023 Report Share Posted June 7, 2023 On 6/5/2023 at 11:03 PM, rwabdu said: Question for you all, sounds like some of you are leaning at mixture settings above 75% BHP? ie "Full throttle at 2500 rpm up to 9500 at most and a little over 10 gph" I always thought settings above 23 x23 I had to keep the mixture in full on an o360 bellow 10,000 msl to stay below 75% bhp. Or, was that because my poh was written pre-engine monitoring technology? I lean based exclusively on CHT, which I try to keep in the 340 range (for no particular reason other than it sounds like a good number). In the winter it means I can fly WOT, 2400 rpm and lean pretty much immediately after takeoff, and even then, the temps struggle to stay above 300. In the summer, I am also WOT - 2400 rpm and only start leaning once the CHTs start dropping which really depends on OAT. In other words yes, I lean at power settings above 75% without any issues (yet). Quote Link to comment Share on other sites More sharing options...
Jim Peace Posted June 8, 2023 Report Share Posted June 8, 2023 my last flight brining it to annual, prob around 50-75 degrees rich of peak. my FF is a bit higher than book... my POH says that at 5000 feet I should be at 149 knots and burning 10.9 gallons per hour. Also says there could be a 3% error. So I am right in the ball park for a 59 year old plane. 1 Quote Link to comment Share on other sites More sharing options...
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