Carburetor icing

[Nobody96]

Hi,

 

I couldn't find a complete list of the changelogs anywhere so I am wondering if carburetor icing is modeled yet. I took the P-51 for a ride the other day and my engine died of a piston seizure at angles 20. Before that happened, all temperatures where fine and I wasn't even running on full continuous because the engine was running rough. The carburetor temperature was quite low, but during the short time I switched to full mil it got up and the engine was running smooth again. Thats why I suspected carburetor icing, but than all I could find in the forum is that it is not implemented currently.

 

-Mathias

[howie87]

Your RPM was probably too low for your manifold pressure. Running low RPM high manifold is a sure fire way to ruin your engine. Carb icing is not modeled.

[sobek]

The single most reason for rough running currently are fouled spark plugs. Run the engine on TO power or preferably on max cont. for a few minutes and it should return back to normal.

[-MadCat-]

Just to further support sobek's point.

 

Excerpt from an F-51D Handbook:

SPARK PLUG FOULING

Engine roughness may be the first sign of spark plug

lead fouling, but to determin whether the plugs are at

flault, clean out engine by advancing propeller control

to 3000 rpm and throttle to 61 in.Hg and run engine

continiously for one minute. Return throttle and pro-

peller control to cruise setting and notice whether

roughness persists. If rouchness is still present, check

for carburetor ice; then, if engine is still rough, reduce

power to best operating setting and proceed to nearest

base for landing to determine trouble.

 

Note

During prolonged cruising flight, "clean out"

engine every 30 minutes. Also "clean out"

engine before landing.

Am "cleaning out" my engine all the time like that, never had any trouble with the one minute max power

and engine always runs smooth (provided you operate it within limits the rest of the time).

AFAIK, carburetor iceing isn't modeled yet.

 

Greetings

MadCat

[dooom]

Interesting - I blew an engine at 42000 on a bomber intercept mission...my carb temps were in he toilet so I presumed it was icing... It would be nice to have it modelled for the rrg release

[Nobody96]

Hey, thanks for all the answers. On a second try, I kept my temperatures a little lower and "cleaned out" the engine after the transition from low to high blower and all worked like a charm.

 

-Mathias

[Swoop73]

As a general rule, carb icing becomes less of a threat as the bore of the carb becomes larger. The T-6 doesn't even have a carb heat control, as I remember. Think of it this way. Icing conditions "Sometimes described as a Temp/dewpoint spread of less than 11C" and a quarter inch of ice forms in the carburetor. In a Cessna, the carb throat might be around 1.5 inches, so that ice buildup is a big deal. I don't know the throat diameter in the 51 but it must be 5-6 inches. That same ice deposit would hardly be noticed.

 

This is an approximation. Not writing this with a Lycoming manual in my lap, but it's the general idea. I can find out from pilots who flew P-51's in appalling conditions in Italy. Never heard of carb ice being one of their worries. Losing control in clouds, mid air collisions and friendly fire were probably more feared than enemy action. I'll have to ask about carb icing.