I installed 5 remote temperature probes in my engine compartment to assess the effectiveness of various cooling mods. Probes were located on the carburetor bowls, fuel manifold (the spider), engine-driven fuel pump (aft side) and gascolator (fwd side.) Observations were made on the one-hour flights at 15 minute intervals and after a 10 minute "fuel stop" with the oil filler door open.
Herewith is a summary of my hand-written observations. Addition of a shroud and blast tube (1 1/4" scat to RH "eye") on gascolator lowered the average in-flight temperature about 40F but didn't help after the 10 minute rest. I'm thinking prop blast after startup would cool this some for the "hot" takeoff.
Flight with ceramic-coated headers and muffler showed virtually no cooling effect in-flight but had a marginal effect at the 10 minute mark, lowering temps at some locations but not others. I had expected more from this expensive mod, especially since the carbs sit on top of the headers.
I will be looking at Dynon download data for any good news on oil temps with the ceramic exhaust components. Will post if I can find anything significant.
In-flight temps ranged from 100-113F for the fuel pump to 120-130F for the carb bowls. I considered a blast tube to the fuel manifold but temps there never exceeded 123F.
Conclusion: Proximity to the muffler, radiator and coolant hoses makes the gascolator a hot spot. Add in the turbulence-generating 90 degree outlet fitting and there may be some potential for vapor formation. I can't prove anything but a reading of 171F there right after shut-down on the control flight makes me think that car gas was starting to cook.
Laboratory conditions were *not* possible; ambient temps were around 95F each day. The digital meter is only as good as the 8 year-old Chinese girl who assembled it. I might be able to convert the raw data into a document of some kind and will attempt to email it to anyone who PM's with their email address. Can't promise anything, though.
Thanks to Joe in Mich. for guidance and DonInTex for the equipment. Hope this will be helpful to those flying in hot weather. If you don't like my methods or conclusions, please conduct your own test; I would very much like to get more data from people who know what they are doing.
Jim
RV-12 #264
Flying about 30 hours
Herewith is a summary of my hand-written observations. Addition of a shroud and blast tube (1 1/4" scat to RH "eye") on gascolator lowered the average in-flight temperature about 40F but didn't help after the 10 minute rest. I'm thinking prop blast after startup would cool this some for the "hot" takeoff.
Flight with ceramic-coated headers and muffler showed virtually no cooling effect in-flight but had a marginal effect at the 10 minute mark, lowering temps at some locations but not others. I had expected more from this expensive mod, especially since the carbs sit on top of the headers.
I will be looking at Dynon download data for any good news on oil temps with the ceramic exhaust components. Will post if I can find anything significant.
In-flight temps ranged from 100-113F for the fuel pump to 120-130F for the carb bowls. I considered a blast tube to the fuel manifold but temps there never exceeded 123F.
Conclusion: Proximity to the muffler, radiator and coolant hoses makes the gascolator a hot spot. Add in the turbulence-generating 90 degree outlet fitting and there may be some potential for vapor formation. I can't prove anything but a reading of 171F there right after shut-down on the control flight makes me think that car gas was starting to cook.
Laboratory conditions were *not* possible; ambient temps were around 95F each day. The digital meter is only as good as the 8 year-old Chinese girl who assembled it. I might be able to convert the raw data into a document of some kind and will attempt to email it to anyone who PM's with their email address. Can't promise anything, though.
Thanks to Joe in Mich. for guidance and DonInTex for the equipment. Hope this will be helpful to those flying in hot weather. If you don't like my methods or conclusions, please conduct your own test; I would very much like to get more data from people who know what they are doing.
Jim
RV-12 #264
Flying about 30 hours
