Carb Heat in rain

[rockwoodrv9a]

I would still suspect that the carb heat is misrigged, leaving it partially on. The sump's heat can't fight the cold that much. Cold air coming in can suck so much heat out of the carb body it's not funny, and adding the pressure drop and evaporation of the fuel really refrigerate it.

I built the plane and thinking back at how the carb heat is designed, the location is right near the throat of the air box. It is by no means air tight and a design that works, but it could allow some hot air to always flow through the carb. I flew 2 flights today in 35 F for a total of 3.2 hours. There was reported icing above but we stayed just below the clouds. Looking at the data the lowest temp for the carb was 82 and the high was 109. Next time I have the cowl off I will give it a once over and see if improvements could be made. If I can keep the temp lower I should be able to get better power. Thanks for the tip.

 

[Dan Thomas]

I built the plane and thinking back at how the carb heat is designed, the location is right near the throat of the air box. It is by no means air tight and a design that works, but it could allow some hot air to always flow through the carb. I flew 2 flights today in 35 F for a total of 3.2 hours. There was reported icing above but we stayed just below the clouds. Looking at the data the lowest temp for the carb was 82 and the high was 109. Next time I have the cowl off I will give it a once over and see if improvements could be made. If I can keep the temp lower I should be able to get better power. Thanks for the tip.

Make sure the carb temp gauge isn't way off. The next time you fly, see if the gauge reads ambient temperature before doing anything else.