Human Powered Helicopter : Straight Up Difficult

It’s difficult to build a working four-rotor helicopter that spans 100 feet and only weighs 80 pounds. It’s even harder when your engine is a 0.7-horsepower person. But one team of engineering students is trying to do just that. Love this great NPR piece about engineering students at University of Maryland trying to win a three-decades-old contest for human powered flight.