page_title: Piasecki HUP Retriever
section_title: Variants
hierarchical_section_title: Piasecki HUP Retriever / Variants
caption_attribution_description: English: Recovery of the crew of a U.S. Navy Grumman AF-2 Guardian from Anti-Submarine Squadron 22 (VS-22) by a Piasecki HUP of Helicopter Utility Squadron 2 (HU-2) after the plane was forced to ditch immediately after launching in 1953. The parent escort carrier USS Block Island (CVE-106) is standing by in the background.
context_page_description: 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.
context_section_description: XHJP-1
  Prototype, powered by a 525 hp (391 kW) Continental R-975-34 piston engine, equipped with large sloping endplate fins on the horizontal stabilizers. Piasecki-Vertol designation was PV-14. 2 or 3 produced.
  HUP-1
  Utility transport and search and rescue helicopter for the US Navy, largely similar to XHJP-1, Piasecki designation was PV-18. 32 built.
  HUP-2
  Improved version, 550 hp (410 kW) Continental R-975-42 piston engine, horizontal stabilizer endplate fins eliminated. 165 built for the US Navy, 15 for French Aeronavale. Redesignated UH-25B in 1962.
  HUP-2S
  Anti-submarine warfare version of HUP-2 fitted with dunking sonar. 12 built.
  HUP-3
  Naval utility conversion of H-25A aircraft transferred from US Army: 50 to US Navy, 3 to Royal Canadian Navy. Remaining US Navy aircraft redesignated UH-25C in 1962.
  H-25A Army Mule
  Utility transport helicopter for US Army, similar to HUP-2 but powered by a 550 hp (410 kW) Continental R-975-46A piston engine, and fitted with large doors, power-boosted controls, and strengthened floors. 70 were delivered from 1953, but they were unsuitable for front-line use, with 53 transferred to the Royal Canadian and US Navies in 1954–1955, and the remaining helicopters used for training, being withdrawn from army service by 1958.
  UH-25B
  HUP-2 redesignated after 1962.
  UH-25C
  HUP-3 redesignated after 1962.
caption: A U.S. Navy HUP plane guard doing its work in 1953
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