Piasecki H-25

For other uses of "H25" see H25 (disambiguation).

H-25/HUP Retriever
A U.S. Navy HUP-1 Retriever aboard the USS Midway (CVB-41) in the early 1950s
Role Utility helicopter
Manufacturer Piasecki Helicopter
First flight March 1948
Introduction 1949
Retired 1964
Primary users United States Navy
United States Army
Royal Canadian Navy
French Navy
Number built 339

The Piasecki H-25 Army Mule/HUP Retriever was a compact single radial engine, twin overlapping tandem rotor utility helicopter developed by the Piasecki Helicopter Corporation of Morton, Pennsylvania during the late 1940s and produced during the early 1950s. The company changed its name in the 1956 to Vertol Aircraft Corporation and subsequently was bought by Boeing Aircraft Company in 1960, and became Boeing-Vertol.

Contents

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 Navy ships including aircraft carriers, battleships, and cruisers. The prototype was designated by the Navy as the XHJP-1, and first flew in March 1948. It was selected by the Navy for production, as the HUP-1 in a side-by-side flight evaluation against the Sikorsky XHJS-1. It entered service with the Navy and USMC from 1949.

Operational history

Versions of the HUP built for the U.S. Army were designated H-25 Army Mule. 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 design featured two three-bladed, 35-foot-diameter (11 m) rotors in tandem in which blades could be folded for storage in ships’ hangars. The HUPs were powered by a single Continental R975-46 radial engine, with a take-off rating of 550 hp (410 kW). To provide rescue without crew assistance, an electrically operated door, available after folding the copilot’s seat forward, opened through which a rescue sling could be lowered from an overhead winch.

The HUP was produced for the Navy in four versions: HUP-1, -2, and -3. The HUP-2 was the first production helicopter equipped with an auto-pilot. Edo tested a HUP-2 with a fiberglass hull and outrigger floats for amphibious operations. [1] In addition to those delivered to the U.S. Navy and Army the HUP/H-25 helicopter was also delivered to the Canadian and French Navies. A total of 339 aircraft were delivered over the 20-year life of the aircraft.

The US Army H-25 designation was adopted by the other services in 1962. The final units were withdrawn from US service in 1964. It also served with the French Navy from 1953 to 1965.

Variants

XHUP-1
The first two prototypes.
HUP-1
Utility transport, search and rescue helicopter for the US Navy, powered by a 525 hp (391 kW) Continental R-975-34 piston engine.
HUP-2
Improved version, powered by a 550 hp (410 kW) Continental R-975-46 piston engine. Later redesignated UH-25B in 1962.
HUP-2S
This designation was given to 12 HUP-2s. The HUP-2S was an anti-submarine warfare helicopter, fitted with a dunking sonar equipment.
HUP-3
Utility transport helicopter for the US Navy, powered by a 550 hp (410 kW) Continental R-975-46A piston engine. Similar to the H-25A "Army Mule", later redesignated UH-25C in 1962.
H-25A Army Mule
Utility transport helicopter for the US Army, powered by a 550 hp (410 kW) Continental R-975-46A piston engine, fitted with large doors, power-boosted controls and strengthened floors. It was called the H-25A "Army Mule". Seventy were delivered from 1953, but they proved unsuitable for front-line use, with 50 transferred to the Navy from 1955, and the remaining helicopters used for training, being withdrawn completely from Army service by 1958.[2]

Operators

Specifications (HUP-3)

General characteristics

Performance

See also

Related development
Aircraft of comparable role, configuration and era

References

  1. ^ Popular Science. Feb 1958. 
  2. ^ Harding 1990, pp. 197–198.

External links