Why do most American made jet engines, helicopters and prop driven planes have their fans, props and rotors turning anticlockwise when viewed from the front (jet engines and plane propellers) and from the top (helicopters), whereas the fans, props and rotors of European ones turn clockwise?

Question

I know there are exceptions like the General Electric GEnx fan turning clockwise despite being an American made jet engine.

In: Engineering

Answer 1

There is no technical reason why one direction of rotation is better than the other. The European vs American difference in rotational direction predates jet engines, with piston engines also following this convention back to the beginnings of engine production.

One possible reason for this difference is that the convention of how to lay out technical drawings in the US and Europe is different, so something that rotates in the same direction based on how drawings are laid out, would result in a machine that rotates in the opposite direction in the finished machine.