Preventing carb ice, using a Teflon coated throttle plate, shaft and screws plus a gasoline icing inhibitor. Long-EZ builder/flyer Ken Clunis sent us a copy of Mechanical Engineering Report LR536 from the National Research Council of Canada titled "Aircraft Carburetor Icing Studies" by L. Gardner and G. Moon. This report is quite extensive and obviously very carefully researched. The summary of the test results states: "A study has been made of the effects of gasoline icing inhibitors on aircraft carburetor icing. An engine test was developed and used to evaluate various types of icing inhibitors. The results obtained showed that aircraft carburetor icing can be prevented by the inclusion of additives in the gasoline.
The use of a Teflon-coated throttle plate to prevent ice adhesion was studied and found to virtually eliminate any ice formation on the plate. The use of ethylene glycol monomethyl ether (EMGE) at 0.10 to 0.15% by volume in the gasoline and the Teflon-coated plate was shown to prevent both carburetor and fuel system icing. Ken has followed up on this report and has had his shaft, screws and throttle plate Teflon-coated. He is currently running his Long-EZ with these parts installed and is using Prist "Hy-Flow" (not "Lo-Flow" which is alcohol based and may be hard on your epoxy in the fuel tanks), which he says is the best source of EMGE. He has installed a carburetor temperature gauge and is very pleased with his results so far.
Ken says that he had his carburetor shaft, screws and throttle plate Teflon-coated (black) at: Durable Release Coaters, Ltd. 4 Finley Road, Bramalea, Ont., L6T IA9 Canada 416-457-2000. His contact there was Dave Lund, himself a well informed expert on carb icing. There is a $75.00 minimum charge. If enough people wanted to get it done, the price would run about $15.00 for shaft, screws and plate in quantities of 10. We sure appreciate the effort Ken put out to obtain this information. It sounds like an excellent preventive measure that EZ/Defiant pilots may wish to try.