Engineers have historically faced two obstacles when designing electric aircraft. Batteries that run the electric motors have been too heavy and not energy-dense enough to provide sufficient power. And the consequences of failure were too high: Running out of power would all but assure a crash landing.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.