Mooney Bravo m20m 1998 temps

[pkofman]

Probably been asked a thousand times but ill check in  from a hot Canadian summer with this question

It has been a hot summer here in Toronto ( ground temps  generally in the low 30's c)

I find that flying around 10k i get some pretty hot cylinder temps

Typically i fly 29/2400 and lean to tit  approx 1600-1625 ( a tiny bit rich to keep things cool ) but with the cowl flaps closed i get some cht creep into the low 400's ( fuel flow at this setting is around 19.8)

My knee jerk reaction is to trail the CF's  1/2 open and it helps to keep the cht just under 400. I know the cht limit is higher than 400 but I have read here that ( 400) is proably a healthy limit ). If i close the cf's, the cht willl creep up

So is this normal and am i being overly cautious or would low 400's be acceptable given 1600-1625 on the tit

Thoughts 

Peter

[kris_adams]

Hi Peter, I've only flown non-turbo planes so I can't comment on any of the TIT/CHT complications.  In the hot Georgia summers I start opening my cowl flaps at 380 (if it reaches that in cruise) and pretty much always stay below 380 as much as possible.  Some people have adjusted their cowl flaps such that they are open a bit even when "closed".  I'm not sure if that's possible on the M.  Good luck!

[LANCECASPER]

1 hour ago, pkofman said:

Probably been asked a thousand times but ill check in  from a hot Canadian summer with this question

It has been a hot summer here in Toronto ( ground temps  generally in the low 30's c)

I find that flying around 10k i get some pretty hot cylinder temps

Typically i fly 29/2400 and lean to tit  approx 1600-1625 ( a tiny bit rich to keep things cool ) but with the cowl flaps closed i get some cht creep into the low 400's ( fuel flow at this setting is around 19.8)

My knee jerk reaction is to trail the CF's  1/2 open and it helps to keep the cht just under 400. I know the cht limit is higher than 400 but I have read here that ( 400) is proably a healthy limit ). If i close the cf's, the cht willl creep up

So is this normal and am i being overly cautious or would low 400's be acceptable given 1600-1625 on the tit

Thoughts 

Peter

You probably don't even need to keep the cowl flaps half open, since on the Bravo you have the infinitely adjustable electric cowl flaps. When I get in that situation I just open them maybe a quarter and the temps drop enough to stay below 400. I think it's wise engine management to stay below 400 either by adding fuel or some cowl flaps. Another thing to check when you are looking at your engine the next time are your baffle seals. Make sure they aren't letting air go by over the top.

[Danb]

No question about checking the baffles, your somewhat hotter then my Bravo, at similar outside temps, I will be 31/2300...tit 1600 or little under, fuel flow 18 gph, CHT,s 360-380. Just landed from a 2 hour trip, 9000ft, 1600 tit, 31/2350  18.3 gph, 370 cht’s, 188 knots. Detroit to Wilmington. 2 hours, gotta love our Bravo’s

 

[Danb]

[pkofman]

6 minutes ago, Danb said:

Hope you had a good flight and just north of you we are getting a serious cold front with lots of weather today . I will check the baffles from sure. I tend to operate a bit differently at 29/2400 so might be a bit different but not much except that my cht is quite different

 

 

Edited July 26, 2018 by pkofman

[Danb]

I worked on my baffling a couple yrs ago and cooled about 20*

[carqwik]

Plenty of experience in hot Arizona with the Bravo.  Yes it runs hotter in the summer.  Definitely need the cowl flaps in trail to keep temps in acceptable ranges in cruise at those power settings.  Or just reduce the MP another 2" or more...

[LANCECASPER]

Actually opening the cowl flaps a little doesn't affect cruise speed much if any. On some airframes there have been some tests done that show that since the air is restricted less, cowl flaps slightly open increases cruise speed by a knot or two. Full open affects it considerably though.

[FoxMike]

Years ago I replaced the factory cowl seal with a silicone material.  Head temps dropped more than 25dF.