I don't know how Dave Garber calculated the Bell gear box bearing loads but
don't forget there is at least 600 ft pounds of bending on the
prop shaft due to gyro loads. That takes a bit of bearing
spread. Heat treated billet steel will work fine for
a prop shaft. Only draw back is it will be a bit heavier than forged.
Not the same situation as a crank shaft where forging is near essential.

Paul Lamar ...No rotor no motor.

Paul or anyone.

Can you recommend a good alloy and heat treatment to use for prop shaft?

Thanks


Doug

4340 chrome molly steel. Heat treat to Rc 65
Use large fillets and have it shot peened.