Bob Lee wrote: > What's all this suck > blow stuff anyway? The problem here is the terms being used, not the > engineering.
That message Dan forwarded was a little out of context. He'd emailed me earlier about the NACA ducts that I used to exit the cowling area, so I knew he was talking about the exit, not the entrance. The original NACA description that I read said it would work either way, but later research proved that they didn't do too well in the exit mode. There was a recent Kitplanes (or maybe Sport Aviation) article that highlighted that, saying that the conventional straight ramp (just like a NACA duct, but without the curved sides) worked far better. I can tell you that even if the NACA duct did work in the way that mine are, the exhaust is concentrated right at the point where it necks down, so the ramp would be far better from that standpoint alone. If I ever have my plane upside down again, I'll just cut them out straight and reglass them into straight ramps, but they work OK for now. Dan's probably still looking for that recent article that goes into the details. I haven't read it yet, as I have a 3' tall stack of magazines that I haven't managed to get around to reading since my plane's been flying... Mark Langford, Huntsville, Alabama see KR2S project N56ML at http://home.hiwaay.net/~langford email to N56ML "at" hiwaay.net
