CHT's in a 252

[FlyingAggie]

[peter]

Quote: FlyingAggie

He also claims that because of the lower temperature most 252 engines will make TBO.  

[flashf16]

Alan, at 100 ROP and 25 to 50 LOP I'm consistently between 350 and 380 on all cylinders (1980 M20K 262 with the MB3 engine)--typically running 65-75% power.

Ryan

 

[JC252MB]

I don't think I've ever seen a CHT in my airplane over 400 because of my actions at any altitude.  My takeoffs are all max MP, 2700 RPM and FF leaned for 1450 TIT.  My CHTs hang in around 360-380.  I only use one cruise setting and that's 28MP, 2500 RPM, FF leaned to 1450 (13.0 gal +/- .5) and cowl flaps closed.  Again, regardless of altitude my CHT numbers are 360-380 across the board and my true airspeed is within a knot or two of book by any method you want to use.  I re-read that article from time to time and I believe the author is Bob Kromer but I could be wrong.

I'm happy and the airplane seems to be happy too.  It's currently in annual so let's see how happy I am later.

[JC252MB]

I don't think I've ever seen a CHT in my airplane over 400 because of my actions at any altitude.  My takeoffs are all max MP, 2700 RPM and FF leaned for 1450 TIT.  My CHTs hang in around 360-380.  I only use one cruise setting and that's 28MP, 2500 RPM, FF leaned to 1450 (13.0 gal +/- .5) and cowl flaps closed.  Again, regardless of altitude my CHT numbers are 360-380 across the board and my true airspeed is within a knot or two of book by any method you want to use.  I re-read that article from time to time and I believe the author is Bob Kromer but I could be wrong.

I'm happy and the airplane seems to be happy too.  It's currently in annual so let's see how happy I am later.

[FlyingAggie]

JC252MB,

I am assuming your K is a 252 based on your user name and your N number N252MB?  If so, that might be a little confusing if we were both talking to the same ATC controller ;-)  At 28" & 2500 RPM, what percent power do you reckon your running?

Alan

[JC252MB]

Yup, the first two letters are my name and the 252MB is the tail number.  Performance charts say 75% power so I'm gonna go with that.  Airplane is just about out of annual with nothing big to talk about which is a very good thing.  More than likely the airplane is going up for sale once I have it back as my mission needs have really changed.  Anyone looking for a really nice 252?

[Earl]

A couple of comments.  I own an 86 252 and have an EDM-730.  At cruise I generally see CHTs from 290's (coolest) to 370's (hottest) when over 65% HP at 100dF ROP.  Unless you are flying at 65% or lower power setting running the engine at 50 dF ROP is the worst possible combination of CHT and cylinder pressures.  If you can run 25-50 dF LOP that is the place to be but if not you should run it either at 100 dF ROP or fly at 65% or lower power settings.