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1. 07:14 PM - Cowling Update 6.1 (Aucountry@aol.com)
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| Subject: | Cowling Update 6.1 |
--> TeamGrumman-List message posted by: Aucountry@aol.com
I made the mod to the rear baffle and dropped the CHT about 20 degrees. I
say 'about' because the temps were still rising past 450 when I pulled the
power back to let it cool. I don't know how high it would have gone.
Today, it was 107 and I was able to climb out at near gross weight and lean
it and it never went over 440. That's #3. The other cylinders never went
over 409. EGTs were about 1320 plus or minus 10. EGTs are very uniform.
I leveled off at 4500 and ran flat out at 2700 rpm and computed a TAS of 144
knots. CHTs actually leveled off to around 390 for 1,2,&4 and 420 for #3.
Outside air temp was 84 at 4500 feet. I climbed to 7500 feet under full
power and leaned and the CHTs stayed about the same, maybe plus 5 degrees.
I climbed to 8500 feet and ran flat out. Level at 8500 feet I recorded 122
knts indicated, 70 degree outside air temp for a TAS of 147 knots. That's at
2700 rpm. Under these conditions, the CHTs settled aroun 380 for all but #3
which was 410. Still 30 degrees warmer.
The next cowling will use a different carb air inlet so the 280 cubic feet
per minute being used by the engine will be available for cooling. On a stock
Tiger/Cheetah with 90 sq inches in inlet area, stealing 12 square inches for
the carb isn't a big deal. On my cowling, 12 square inches is 26% of my inlet
area. Even at that, I'm happy that my cowling is working/cooling so well.
I've already got the scoop built for the next cowling exit. One scoop. 72
square inches of exit area.
Gary
www.AuCountry.com
Home of "Team Grumman"
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