The thing that worries me about adding distance to the fuselage in front of the main spar when using a heavy engine like a Corvair is that if yours doesn't turn out like Mark Jones', you'd be screwed. If you leave that distance per the plans, or maybe only add an inch, and then save the rest for the engine mount to take car of if needed, you'd be better off. If your CG is off by an inch, it's going to take a lot of weight in the tail to fix it. Unlike Mark's, I built my fuselage per plans (in front of the main spar) and even though my engine is only a half inch off the firewall, I'm still in the forward most end of the CG range. And I have elevator counterweights, no forward tank, a tailwheel rather than a nose wheel, and a battery back there.
Both Mark Jones and I are using a rear starter, so it may be possible to slide the engine rearward a tad more with a front starter, but the CG of the front starter engine is going to be further forward than the rear starter engine, but that may be a wash if you can slide it further rearward. Like Mark says, it depends on how you build it, or maybe luck. Another consideration is room on the firewall for stuff like oil filter, cooler (if that's where you mount it), and cabin heat box. Inseam length is another one. I'm a 32", and my plane fits me perfectly. If you're shorter you can stand the same setup, but if you're taller you might need the extra inch or two. The height of the panel is another consideration. It's not a simple matter, and may very well have a different answer for each builder... Mark Langford, Huntsville, Alabama see KR2S project N56ML at http://home.hiwaay.net/~langford email to N56ML "at" hiwaay.net --------------------------------------------------------------
