Thanks for the reply, McQuinn. You've given me some useful information that will help my planning. A simple spreadsheet will make things easy. I didn't think there were any/many 4-stroke gas plane engines out there but I did see one mentioned recently in one of the mags. Maybe MAN or Model Aviation.

Since you mentioned prop use with various engines do you happen to have any guidance in that area? For example, if using an 11/6 prop on a .46 2-stroke glow engine change diameter/pitch by X on a .60 4-stroke glow or 40 cc gas engine. I recall a "rule" that states add one to the diameter and subtract one from pitch to get comparable props. Does this work here too, or should the pitch be kept with larger diameters?

Thanks again,
Bidwin.