Here's another project that I have, it was a physics project for school but I thought I could put an Arduino somewhere in there and make it more interesting, and it worked. The hovercraft has a tubular skirt that I made out of duct tape. It has two 50mm EDFs (EDF= Electronic Ducted Fan), one for hovering and one for propulsion, each with 40amp ESCs (ESC = Electronic speed controller). For direction I used a servo to turn the back fan left and right. The propulsion fan and the servo are connected to an RC receiver and I control them from the remote. The hovering fan( the one that blows downwards and produces the lift and onflates the skirt) is connected through the ESC to the arduino and the Arduino sets the speeh of the fan according to the position of a potentiometer. For the code I used the servo library and I connected the signal wire of the ESC to the arduino as it would be the signal of a servo. I just had to change some numbers in the delay statements and it works just fine. Both the Arduino and the lift fan use a second 7.2v LiPo battery( separate from the one used for the servo and propulsion EDF). Go watch the videos for more info. The first video is an explanation on how it works and the second is a drive. It is a very fun project to play with :)I'll show you how to make your own. Hang on to this instructable.