Reality check. - synchronisation of aircraft engines was designed to cut vibration and thus crew fatigue of bomber aircraft.

In 1940 (see the carrot myth - deliberate misinformation) The Luftwaffe still believed that UK home defences used sound location - hence the deliberate desynchronisation of engines over the Uk to try and confuse the sound locators.

Checking with relatives who were old enough to remember, a desynchronised beat was believed as German - though the odds were it was one of ours.

Gareth