electric motors in this case
so more or less silent, with a slight whine at higher speeds.
( the mighty badger Aphrodite, on a bar stool, by your side, Tue 26 Aug 2008, 18:44, archived)

Lotus are busy making a BRRRMMMM synthesizer
to stick into electric sport cars
( broadsword, Tue 26 Aug 2008, 18:49, archived)