Another presentation you could do would be about the drive system itself. How different pitch props give you a certain performance. Also what gear ratios work better with what props. If you use your batteries as your control (eg. you stick with say NiMH 7.4v 750mah packs) you can time the difference between flight times. The paper can be about when you go from X sized prop the plane goes Y fast for Z long. List the happy medium of speed vs duration. Why a higher or lower pitch will give you the performance, etc etc.

Just make sure to check out GWS's suggestions on prop sizes on the gear boxes... You don't want to over do things and burn up the motor, although they are cheap.

http://www.gws.com.tw/english/produc...em/eps400c.htm

--Scott