In the early 1970's aluminum
ground adjustable propellers were put into service.
By 1977 the oil-controlled constant-speed propellers
were introduced. There were two and three blade
versions with varying weights ranging from 14
to 25 lbs. In 1985, after several years of service,
the propeller was officially grounded due to several
random blade failures. Other than the blade failures,
no reports of crankshaft flange problems were
received. Engines that suffered blade failures
were inspected and put back into service; the
service history of these engines indicates that
no long-term problems were caused by blade separation.
