RE: muffler cleaning? and Biplane trainer?
I am building a SIG Hog Bipe, and it is a fairly easy build.
I just solo'd this last weekend, and with some more flights under my belt hope to have the Hog in the air latter this summer.
Take a look in the kit building section, and you will see a Hog Bipe thread. also do a search for Hookedonrc (I think that is his handle) and he had a long thread on building a Hog Bipe.
I hope it flies as well as people say it does.
I saw a person fly one at the field one day and it flew great, but on landing it nosed over onto the engine. I hope moving the landing gear forward a bit will solve that.