One of the most underrated sources of power is human power. If you are off grid, or your power is down you can always pedal or manually turn a crank. That makes sense for generating electricity for simple needs, but imagine human powered helicopters. That is exactly what a team of engineering students over at the University of Maryland is trying to do. It takes a lot of patience, a lot of engineering talent, and a very, very light helicopter design (oh yeah, and the human needs to be strong and have a lot of stamina.
Take a look at this and think of the possibilities!