Bill, Tom, Don, S.,

I read somewhere about a fellow wanting to design his own plane. From the responses he got I gather that designing and building from scratch is awfully complicated.

I mentioned before about looking at the plans on the SPAD (simple plastic airplane designs) web site. I want to try building one like one of those (I haven't decided which one yet, maybe a mid wing) but am wondering if there is some simple way to enlarge the plans that would work successfully on the first try. Do you think it would work to just use a calculator to multiply measurements of a given set of plans by a factor of 1 1/2 or 2 to get the desied size difference? Or is this simple thinking just too simple minded?

Also, is there a generalized set of mathematical proportions that can be used as a guide in designing a plane. For instance: 1) wingspan to wing cord, 2) wing surface area to tail control surface area, 3) distance from wing to tail section etc?

Maybe this is asking for too much. I would guess that it would all get complicated by things like whether the wing is flat on the bottom, semi-symetrical or symetrical. And by things like the location of the wing in relation to the fuse, ie. top wing, mid wing, low wing.

I have looked a little bit for sites on designing, but what I found was the two extremes of, either a folded paper airplane, or an introduction to what looked like a college course in engineering. ha

I don't mind using math formulas. I used them a lot when studying for those HAM radio licenses I got and enjoyed doing that. I even built a few transmitters and receivers (not from scratch) by using formulas and electronics schematics. I just don't want to start taking a course in aerodynamics at this late stage in life.

Someone said, (it might have been you, Bill) "If it looks like it will fly, it probably will." Is it almost that simple?

elad


Sure, I'm old enough to know better. But I'm still young enough that occasionally I get to make the choice. ----- elad -----