"RCE" wrote in message
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"Forrest" wrote in message
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I can't picture an aluminum prop continuously flexing without breaking. A
good one for "Mithbusters". What are you using the boat for? Do you want
to zoom from one side of the lake to the other as fast as you can ... or
pull the kids around on a sled or a skier ... maybe tow a dingy? I would
just stick with the cheaper aluminum and increase the pitch. How much
depends on the above. Good luck


Better stay out of airplanes. Those aluminum wings flex big time. If
they didn't, the wings would break off the first time the plane hit some
turbulence.

Metal will flex without breaking as long as it does not exceed it's yield
strength. The yield strength of aluminum alloys is similar to that of
carbon and stainless steel.

RCE


Not true. There is no B-50 bearing type rating for aluminum. As long as
you stay below the yield strength in the flex in steel, that is true, but
aluminum wants to crack anyway. Airplanes just keep track of any cracks and
when they exceed a defined amount the part is replaced. I would assume the
airframe is designed so a single part failure is not catastrophic.