RE: Maximum altitude??
No, never said horrible, run as big and slow turning a prop as as possible. Keep it as clean and smooth as possible ahead of the propeller. I will volunteer to make power plant suggestions when you get to that point. I will need final airframe dimensions, weight, desired airspeed in flight, max alt. desired, ground and structure to centerline of shaft dimensions so I can suggest the correct propeller/gearbox/motor/esc/batteries. All will be off the shelf, (internet) equipment. But it must be final or near final numbers. This stuff is not cheap. Need to only buy once. Be sure, if going to pusher, that the dimension includes distance shaft to ground at maximum rotation angle. Always have a seperate battery and switch for flight and other onboard systems (no BEC). If things fry, you still want to see and glide. I send a nice spreadsheet. Free of charge.
Brooks