rv9aviator
Well Known Member
I installed a Vetterman crossover exhaust on my RV-9A and found very quickly I had a problem with heat scortching the bottom cowl. The muffler being a larger diameter puts them much closer to the fiberglass. I only have one muffler hooked up for cabin heat and Larry Vetterman said to remove the heat muff from the muffler that wasn't connected to cabin heat. My engine is a carbureted Lycoming 0-320 E3D. After only 2 hours of flight time I noticed some darkening of the fiberglass on the side with the heat muff and much more on the side without the heat muff. Left alone this would surely ruin the cowl. Dan Horton suggested taking a piece of 1/16 fiberfrax from Aircraft Spruce and putting that next to the cowl with a piece of Van's aluminum self adhesive material cut 2 inches bigger all around and taping that down over the fiberfrax. It worked great. Problem solved and everyone tells me my RV is very quiet but has a nice sound.