Racing Tweaks and Tricks


Sport Class racers are an inventive bunch, and they are always tweaking during race week to get the most performance out of their machines. Here’s an example – Race 49 (a Rocketized RV-6) had one cylinder running just enough hotter that Bob Mills was having to enriched the mixture a bit to keep the CHT’s in limits. But richening up the mixture cost him power, and therefore speed.

Bob is running a water cooling sprawl system that has nozzles aimed at every cylinder head to help the regular air cooling, and the crew noticed that the hot cylinder, the one on front on the left side, had its nozzle mounted a little bit high, and since it is right up front where the cooling air comes into the cowl, there was a good chance that the water was coming out of the nozzle and going straight back – not hitting teh cylinder head again.

So the crew was instructed to rotate the Adel clamp that mounts the nozzle to the pushrod tube by about 90 degrees, therefore lowering the nozzle and allowing it to be aimed at the front of the cylinder head – hopefully increasing the cooling!

Will it work? Hey, this is race week, and we won’t know until tomorrow…. And meanwhile similar tweaks are going on throughout the pits. Racing means tweaking if you want to win!

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Paul Dye
Paul Dye, KITPLANES® Editor at Large, retired as a Lead Flight Director for NASA’s Human Space Flight program, with 40 years of aerospace experience on everything from Cubs to the Space Shuttle. An avid homebuilder, he began flying and working on airplanes as a teen and has experience with a wide range of construction techniques and materials. He flies an RV-8 and SubSonex jet that he built, an RV-3 that he built with his pilot wife, as well as a Dream Tundra and an electric Xenos motorglider they completed. Currently, they are building an F1 Rocket. A commercially licensed pilot, he has logged over 6000 hours in many different types of aircraft and is an A&P, FAA DAR, EAA Tech Counselor and Flight Advisor; he was formerly a member of the Homebuilder’s Council. He consults and collaborates in aerospace operations and flight-testing projects across the country.


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