If you do make a helicopter please make the V-22 Ospray! Its a helicopter/airplane!! Its engines rotate giving it better engine performance. In fact, its the fastest helicopter in the world! Check this out:

http://i140.photobucket.com/albums/r6/Picture-Editor/707%20Professional/v-22-osprey-01.jpg
V-22 Osprey in helicopter formation

http://i140.photobucket.com/albums/r6/Picture-Editor/707%20Professional/V-2220Osprey.jpg
V-22 Osprey airplane formation

http://i140.photobucket.com/albums/r6/Picture-Editor/707%20Professional/V-22_Osprey_wing_rotated.jpg
V-22 with wings rotated (for less space taken up which is very useful for the Navy because of the low amount of space for aircrafts to park)