Piasecki H-16 Transporter

The prototypes were evaluated by the United States Air Force and Army, but the crash of the second test aircraft led to cancelling the project.

[1] The design was publicly shown for the first time on 15 September 1953 at the Philadelphia airport.

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 aircraft was a total loss; the two test pilots, Harold Peterson and George Callahan, were killed.

Another view of the first YH-16A prototype
3-view line drawing of the Piasecki H-16A Transporter