Rate1,

Muffler looks pretty sharp. I like the way it kind of blends with the cowling and where the outlet is.

You'll definitely have to open it up some. I forget the ratio of intake area to outlet area. Somewhere between 1.5 and 2 outlet to 1 inlet I think. You might be able to get by with somewhat less where you are.

I've been covering a smaller project in Polycover, and it is what you would expect for something that is lighter. It is the thinnest of the coverings I've used, and seems to have the least adhesive. It works around corners well, and shrinks well (even at the lower heats). I'll be interested in how it holds up at the field. The other low temperature covering I've worked with seem to unshrink on a hot day. By the time I get it back in the air, I think we'll be all out of hot days for the year.