Expert: Paul Soderman - 10/21/2007

Question
If you put a small, radio-controlled helicopter inside a big enough vacuum chamber, would it be able to operate or would the lack of air make it inoperable?  This assumes that the toy helicopter would survive the air evacuation and not get crushed.

Answer
Pete
Assuming the helicopter had an electric motor, the rotor would turn, but the helicopter would not fly.  You need air to fly.  The rotors are like wings - they create lift when moving through air.  No air - no lift.

Incidentally, a vacuum on the outside of a body will not crush it, though an air tight container will try to expand and might burst.  Conversely, evacuation of air from the inside of a container will cause it to crush if it is not strong enough to support atmospheric pressure.
Paul