Maintaining the Piasecki HUP Helicopter 1952 US Navy Training Film FN-7397b

more at http://quickfound.net/

Originally a public domain film from the US Navy, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.

The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).

https://en.wikipedia.org/wiki/Piasecki_HUP_Retriever

Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/

The Piasecki HUP Retriever/H-25 Army Mule was a compact single radial engine, twin overlapping tandem rotor utility helicopter developed by the Piasecki Helicopter Corporation of Morton, Pennsylvania. Designed to a United States Navy specification, the helicopter was produced from 1949 to 1954, and was also used by the United States Army and foreign navies. The HUP/H-25 was the first helicopter to perform a loop and to be produced with an autopilot...

Design and development

The design was a product of a competition by the U.S. Navy in 1945 for a compact utility/rescue helicopter to operate from ships including aircraft carriers, battleships, and cruisers. Either 2 or 3 prototypes—designated PV-14 by the factory and XJHP-1 by the Navy—were built and subjected to a side-by-side flight evaluation against the 3 prototypes of the Sikorsky XHJS-1; however, the XHJS was fundamentally a scaled-up version of the Sikorsky H-5, and the increased weight and size magnified the design's problems with maintaining proper weight and balance under varying loading conditions. The Piasecki won the competition, and with the introduction of the aircraft configuration letter "U" for Utility in the 1950s, the aircraft was ordered for production as the HUP-1.

The design featured two three-bladed, 35-foot-diameter (11 m) rotors in tandem in which blades could be folded for storage; the relatively small rotor diameter allowed the aircraft to use aircraft carrier elevators with its blades fully extended. The tandem overlapping rotor configuration was a development by Piasecki and was used in future helicopter designs by the company and successors including the H-21, HRB-1/CH-46, and CH-47. The original HUP-1 was powered by a single Continental R-975-34 radial engine, with a take-off rating of 525 hp (391 kW), while later versions used the uprated R-975-42 or R-975-46A with 550 hp (410 kW). To aid search and rescue (SAR) operations, the aircraft was equipped with an overhead winch capable of lifting 400 lb (181 kg), which could lower a rescue sling through an electrically-operated door available after the copilot's seat was folded forward.

During a flight demonstration of its capability to withstand high g-force, the type became the first helicopter to perform a loop, albeit unintentionally...