Monday, February 02, 2009

Harold W Petersen 1925-1955

Harold Petersen (left) with co-pilot George Callahan

Harold William Peterson Pilot (right) and George Callahan Co-Pilot

In early January 1956, the second YH-16 test aircraft crashed while returning to Philadelphia from a test flight over New Jersey. The aircraft was a total loss, the two test pilots, Harold Peterson and George Callahan, were killed.

The cause of the crash was later determined to be the aft slip ring, which carried flight data from the instrumented rotor blades to the data recorders in the cabin. The slip ring bearings seized, and the resultant torque load severed the instrumentation standpipe inside the aft rotor shaft. A segment of this steel standpipe tilted over and came into contact with the interior of the aluminum rotor shaft, scribing a deepening groove into it. The rotor shaft eventually failed in flight, which in turn led to the aft blades and forward blades desynchronizing and colliding.
This led to the cancellation not only of the YH-16, but also the planned sixty-nine-passenger YH-16B version. / The Piasecki H-16 Transporter was a tandem-rotor transport or rescue helicopter designed by Frank Piasecki and built by Piasecki Helicopter initially as the PV-15. The prototypes were evaluated by the US Air Force and US Army, but the crash of the second test aircraft led to cancelling the project