Jim is right .... the centrifugal forces dominate.

Consider a helicopter with an articulated head. There is a pin at the root
about which the blade rotates in a flapping motion. The centrifugal force
holds the blade flat and relieves the bending loads in the root area. If the
centrifugal force wasn't there the blades would simply fold up.

Many props with adjustable pitch have similar bearing arrangements.





"Jim Stockton" wrote in message
...
Have a look at:http://www.mt-propeller.com/pdf/manuals/e-118.pdf
which has better illustrations. The bearing itself is a thrust bearing
with
a split inner race to prevent blade loss. The majority of forces on the
bearing would be outward. The pitch mechanism appears to be a lead screw
moving an inner sleeve to change the pitch. In the manual it says that it
takes about 1 minute to go from feathered to flat pitch implying a large
number of turns of the motor. That would pretty well secure the blade from
rotating about it's axis (pitch wise) because of the locking action of the
thread.
My 0.02 anyway.
Jim Stockton
"Joe" wrote in message
om...
For all you prop gurus out there...

A ran across this drawing and something struck me as odd... why is the
prop blade only being held in with one bearing? Wouldn't it want to
rotate about this bearing slightly and put a lot of force on the pitch
change mechanism?

Or in other words, why isn't the blade held rigidly?

http://www.mt-propeller.com/pdf/datsheet/mtv-23.pdf


Joe