M20E-1964 Posted May 17, 2012 Report Posted May 17, 2012 The person I bought my M20 from said that he flys cross countries with the cowl flaps open for better cooling. What do other M20 owners think? What kind of speed I provement can you expect with them closed? Quote
Bolter Posted May 17, 2012 Report Posted May 17, 2012 This is for my J-model, but I don't like the noise of the cowl flaps when opened (full or trail position) at cruise speeds. If I can keep cool with them closed and adding more fuel or going a little leaner (depending on conditions), that is what I do. I figure that if I can hear the air hitting them open cowls, that they are probably being stressed. The speed impact is a secondary concern as I am still reveling in the massive speed increase over what I used to rent. Quote
scottfromiowa Posted May 17, 2012 Report Posted May 17, 2012 A knot or two, but there is a placard on the cowl flap control for speed max open. If you have a multi-probe temp system you will be able to see that you are fine with them closed in cruise. If it's not then you have a baffling or engine management issue. Quote
OR75 Posted May 17, 2012 Report Posted May 17, 2012 I would think that at cruise and level flight, I would enrich mixture or throttle back if I saw the oil temperature was getting too high. very rare when that is needed (low oil level and very hot outside) Quote
danb35 Posted May 17, 2012 Report Posted May 17, 2012 What Scott said--and if you don't have a multiprobe engine monitor, install one. You shouldn't need to cruise with the flaps open--if you're running too hot, lean more. Well LOP keeps things nice and cool. Quote
Piloto Posted May 17, 2012 Report Posted May 17, 2012 Quote: gmcd The person I bought my M20 from said that he flys cross countries with the cowl flaps open for better cooling. What do other M20 owners think? What kind of speed I provement can you expect with them closed? Quote
John Pleisse Posted May 17, 2012 Report Posted May 17, 2012 Put them in "trail" for the same results. Remember, trail or full open will affect your heater shroud and interior heating in in the winter. Quote
Newmooneyguy Posted May 17, 2012 Report Posted May 17, 2012 My oil temp always runs high for some reason, CHT's are always OK. I just crack open the cowl flaps and it makes a big difference. Quote
Mooneyjet Posted May 17, 2012 Report Posted May 17, 2012 In my short flying hours with m20C I keep the cowl doors close and I find my cht to stay cool about 300 running 75 rop but then I'm up in Canada where still fairly cool temperatures. Quote
Bolter Posted May 17, 2012 Report Posted May 17, 2012 Quote: scottfromiowa A knot or two, but there is a placard on the cowl flap control for speed max open. If you have a multi-probe temp system you will be able to see that you are fine with them closed in cruise. If it's not then you have a baffling or engine management issue. Quote
Lood Posted May 18, 2012 Report Posted May 18, 2012 Speed limit with cowl flaps open for my F is 150mph. Quote
Becca Posted May 23, 2012 Report Posted May 23, 2012 Quote: gmcd The person I bought my M20 from said that he flys cross countries with the cowl flaps open for better cooling. What do other M20 owners think? What kind of speed I provement can you expect with them closed? Quote
M20E-1964 Posted May 23, 2012 Author Report Posted May 23, 2012 I just flew x-country for about 5 hours.... with the cown flaps closed temps were fine. Open, closed, whatever, oil temp is always a bit on the high side of the green arc. Cylinder Head temp is always mid of the green arc. So far, I havent seen any adverse affects of closing them. Quote
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