Propellers and engines?!?

Question

ok i have made a perfectly shaped, sturdy Boeing 737 out of paper!!! now it flies beautifully except the fact that it has no thrust so the bottom dips in and it crashes shortly. so my question is how do yhou make a nice propeller or electric motor homemade?!? and don't say it won't work because this plane is really strong! we put lots of stuff on it to see if it can carry it and it could so what do i do?

also the plane's engine (propeller) space is about as big as your fist from a side view.

Answer 1

If 'the bottom dips in and it crashes' means the CG is out. Fix the CG first and see how it flies. You can fix a motor and a  propeller in each of the engine nacelles and see if it makes the aircraft fly. You would need strong motors and the propellers would need to be run at very high RPM to give you any degree of success in flying that machine. You cannot make the propellers since these are precisely designed items. In your case you would need ducted fans to keep your aircraft looking realistic.

PS: With paper construction, would you have the mountings for the motors strong enough to handle the required power outputs.

Answer 2

It's not a matter of aircraft strength, it's a matter of thrust to weight.  The best you can do for a light power source is probably a rubber band powered propeller.  If you want to go electric, you need a light battery, light motor and propeller.  Get a cheap wood airplane at Wal-mart in the toy section and use the rubber band and propeller out of it.