Believe it or not, mighty military plane maker Lockheed Martin has been designing cheap toy helicopters (WO 03/049830). They take off, hover and land vertically with military efficiency.
A vertical cylinder, like a flashlight torch, has a motor and twin-blade propeller on the top, and three fixed fins on the bottom – but no batteries. Instead it houses a lightweight capacitor. Before lift-off, you charge up the capacitor from a powerful battery. When you disconnect the battery and press a switch the capacitor discharges through the motor, sending the miniature helicopter leaping skywards.
