Somebody mentioned the March 2006 issue of Sport Aviation article on engine cooling, which states that NACA ducts don't work so great in reverse. This is what I have on my plane, and I don't know about cooling, but I can tell you that pointing your exhaust pipes at the narrowing duct doesn't work so great. I guess it works to some extent, but you can imagine that thing probably gets pretty hot.
When I came up with this bright idea, I found the original NACA paper that touted it as both an inlet and an outlet, but later research apparently exposed problems with the outlet part of the theory. Unfortunately, I didn't read that one! Bottom line is that mine would probably work better as a simple ramp that never tapers. Keep that in mind if you are deciding to copy that feature of my airplane. I got some more flying in this afternoon, flying up to Sewannee, TN for a few landings on their 3600' runway that's famous for its treachery, being perched on the side of a mountain. I did a touch and go, but after realizing that the runway was uphill and had some awfully tall trees on the far end ( ! ), the rest of my landings were "full stop".... Mark Langford, Huntsville, Alabama see KR2S project N56ML at http://home.hiwaay.net/~langford email to N56ML "at" hiwaay.net
