The trouble with handed props is that it means different two terminal reduction gears in the same plane, in fact two diferent power eggs in the same plane. All engines are created equal (wow!), only they turn the prop this or another way depending on reduction gear - a prop turns at much lower RPM than the engine. So if in a say B-25 you need to change engines you just pick one from maintenance stocks, in case of a P-38 you have to have right- and left-handed engines in stock, two different sets of gears, etc.

A complication for little benefit, something that is easily corrected by application of some rudder pedal on take off.

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