ryanbatc 4 Posted May 6, 2011 Share Posted May 6, 2011 What did I do now? I'm stumped with this one. OAT +20, prop in the green arc whole time, oil temp/press in green, CHT normal. Just doing patterns, eventually I lose engine rpms and prop stops. Link to comment Share on other sites More sharing options...
dwhite601 0 Posted May 6, 2011 Share Posted May 6, 2011 Did you apply carburetor heat for lower throttle settings? It sounds like a carb ice issue or fuel starvation. Assuming you had sufficient fuel with any water drained out, I'd suspect carb ice. Don't let the outside air fool you. It's the temperature on the inside of the carburetors that matters. A partially closed throttle causes a restriction in airflow. The suction from the engine causes the air pressure in the carburetor to drop. The air temperature drops and condensation forms. If the resulting temperature is below freezing, ice blocks the carburetor throat. A rule, I've been taught is to always apply carb heat when below 20" manifold pressure. Remember to turn it off after landing. Link to comment Share on other sites More sharing options...
Jigsaw 20 Posted May 6, 2011 Share Posted May 6, 2011 I think 20° in humid air are wonderful icing conditions. Definitely consider carb heat if the visibility is reduced (lots of moisture in the air), even at those temperatures. Link to comment Share on other sites More sharing options...
twright 7 Posted May 6, 2011 Share Posted May 6, 2011 Yep i'd say you're losing engine power due to carb ice. My flying instructor is really quite hot on the use of carb heat, i've always been taught to check it every 10 minutes or so whilst cruising along and to put it on when reducing power for a descent. FSX does over-exaggerate carb icing but it's a very common source of engine failure in the real world too. Regards, Tom Link to comment Share on other sites More sharing options...
ryanbatc 4 Posted May 8, 2011 Author Share Posted May 8, 2011 Jeeese I just went through this with Simon - I thought loss of MP was carb icing. Yeah I was at low power settings intermittenly for patterns. Looks like I need to seriously brush up on systems theory Link to comment Share on other sites More sharing options...
Snave 466 Posted May 8, 2011 Share Posted May 8, 2011 Well within the zone, depending on the dew point (ambient is only part of the story). Link to comment Share on other sites More sharing options...
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