First flight of the Piasecki HRP-1
Friday, August 15, 1947
This is a Notable Operational milestone.
Description:
This was the first tandem helicopter to go into production service. It was the first of an initial batch of 10 for the U.S. Navy.
Source: "Helicopters and Other Rotorcraft Since 1907", Kenneth Munson, Blandford Press, ISBN 0 7137 0610 4, Page 173
