twinman,
A little food for thought: those four "dummy" props spinning will create a lot of drag. I read an article several years ago about a Ford Tri-Motor model, I think, that had one engine in the nose and 2 dummies. The author mentioned, the power had to much larger than needed for a single of same size, due to the drag of the dummies. I can't remember how much or any of the details, except that it was significant.