H-25/HUP Retriever | |
---|---|
A U.S. Navy HUP-2 from USS Franklin D. Roosevelt | |
Role | Utility helicopter |
Manufacturer | Piasecki Helicopter |
First flight | March 1948 |
Introduction | February 1949 [1] |
Retired | 1958 US Army January 1964 RCN 1964 USN 1965 French Navy |
Primary users |
United States Navy United States Army Royal Canadian Navy French Navy |
Produced | 1949–1954 [2] |
Number built | 339 [2][ disputed ] |
The Piasecki HUP Retriever/H-25 Army Mule is 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 be produced with an autopilot and also the first to perform a loop.
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. [2] Either 2 [1] or 3 [3] [4][ disputed ] prototypes—designated PV-14 by the factory and XHJP-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. [3] The Piasecki won the competition, [3] and with the introduction of the aircraft configuration letter "U" for Utility in the 1950s, [5] the aircraft was ordered for production as the HUP-1. [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. [2] 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). [1] 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. [2]
During a flight demonstration of its capability to withstand high g-force, the type became the first helicopter to perform a loop, albeit unintentionally. [2]
The aircraft first entered service in February 1949 with the delivery of the first of 32 HUP-1 aircraft to the US Navy. [1] The improved HUP-2 (Piasecki designation PV-18) was soon introduced with a more powerful engine, deletion of the inward-canted horizontal stabilizer endplate fins, and various minor changes in equipment; a sub-variant equipped with dunking sonar for anti-submarine warfare was given the designation HUP-2S. [1] [2] The HUP-2 was the first production helicopter equipped with an autopilot. [2] The US Navy also tested a radio navigation system called Raydist that allowed an unmanned HUP-2 to be directed from a ground station and by radio ordered to hover within five feet (1.5 m) of the desired point. [6] Edo tested a HUP-2 with a fiberglass hull and outrigger floats for amphibious operations. [7]
An upgraded version of the HUP-2 was built for the US Army and designated as the H-25A Army Mule, but most were quickly withdrawn from Army service and converted for naval use under the designation HUP-3. [1] [2] [8]
In 1954, the Royal Canadian Navy received three former US Army H-25A aircraft, which were modified and redesignated on delivery to conform to US Navy HUP-3 standards. [8] [9] [10] The aircraft were used aboard HMCS Labrador for search and rescue and varied utility duties, and were later used to support construction at Distant Early Warning Line radar sites. [8] [10] The helicopters were subsequently posted to NAF Patricia Bay and naval air station HMCS Shearwater; after the last two were stricken from inventory on 18 January 1964, one aircraft was donated to a technical school and the other two were sold as surplus. [8] [10]
The US Army H-25 designation was adopted by the US Navy in 1962 [1] on introduction of the 1962 United States Tri-Service aircraft designation system. The final units were withdrawn from US service in 1964.[ citation needed] It also served with French Naval Aviation (Aeronavale) from 1953[ citation needed] to 1965. [2]
A total of 339 aircraft were delivered during the 6-year production run. [2][ disputed ] A large number of surplus US Navy aircraft later appeared on the US civil registry, and at least seven were transferred to the French Navy.[ citation needed]
On 7 November 2009, former US Navy HUP-1, BuNo 124925, [11] civil registration number N183YP, [12] collided with high-voltage power lines in Adelanto, California; the subsequent crash and post-crash fire killed all 3 occupants and substantially damaged the aircraft. [12] Operated in association with Classic Rotors, the accident aircraft was the only airworthy example in the world. [11] The National Transportation Safety Board attributed the crash to "The pilot’s failure to maintain clearance from powerlines during en route flight." [12]
For surviving aircraft, hyphenated numbers are original US Army Serial Numbers; six-digit numbers are original US Navy Bureau of Aeronautics (BuAer) Bureau Numbers (BuNo). All 50 H-25A/HUP-3 aircraft transferred from the US Army to the US Navy were given new bureau numbers; 3 aircraft transferred to the Royal Canadian Navy were redesignated, but retained their original US Army serial numbers. [8]
Data from Jane's All The World's Aircraft 1956–57. [39]
General characteristics
Performance
Related development
Aircraft of comparable role, configuration, and era
H-25/HUP Retriever | |
---|---|
A U.S. Navy HUP-2 from USS Franklin D. Roosevelt | |
Role | Utility helicopter |
Manufacturer | Piasecki Helicopter |
First flight | March 1948 |
Introduction | February 1949 [1] |
Retired | 1958 US Army January 1964 RCN 1964 USN 1965 French Navy |
Primary users |
United States Navy United States Army Royal Canadian Navy French Navy |
Produced | 1949–1954 [2] |
Number built | 339 [2][ disputed ] |
The Piasecki HUP Retriever/H-25 Army Mule is 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 be produced with an autopilot and also the first to perform a loop.
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. [2] Either 2 [1] or 3 [3] [4][ disputed ] prototypes—designated PV-14 by the factory and XHJP-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. [3] The Piasecki won the competition, [3] and with the introduction of the aircraft configuration letter "U" for Utility in the 1950s, [5] the aircraft was ordered for production as the HUP-1. [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. [2] 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). [1] 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. [2]
During a flight demonstration of its capability to withstand high g-force, the type became the first helicopter to perform a loop, albeit unintentionally. [2]
The aircraft first entered service in February 1949 with the delivery of the first of 32 HUP-1 aircraft to the US Navy. [1] The improved HUP-2 (Piasecki designation PV-18) was soon introduced with a more powerful engine, deletion of the inward-canted horizontal stabilizer endplate fins, and various minor changes in equipment; a sub-variant equipped with dunking sonar for anti-submarine warfare was given the designation HUP-2S. [1] [2] The HUP-2 was the first production helicopter equipped with an autopilot. [2] The US Navy also tested a radio navigation system called Raydist that allowed an unmanned HUP-2 to be directed from a ground station and by radio ordered to hover within five feet (1.5 m) of the desired point. [6] Edo tested a HUP-2 with a fiberglass hull and outrigger floats for amphibious operations. [7]
An upgraded version of the HUP-2 was built for the US Army and designated as the H-25A Army Mule, but most were quickly withdrawn from Army service and converted for naval use under the designation HUP-3. [1] [2] [8]
In 1954, the Royal Canadian Navy received three former US Army H-25A aircraft, which were modified and redesignated on delivery to conform to US Navy HUP-3 standards. [8] [9] [10] The aircraft were used aboard HMCS Labrador for search and rescue and varied utility duties, and were later used to support construction at Distant Early Warning Line radar sites. [8] [10] The helicopters were subsequently posted to NAF Patricia Bay and naval air station HMCS Shearwater; after the last two were stricken from inventory on 18 January 1964, one aircraft was donated to a technical school and the other two were sold as surplus. [8] [10]
The US Army H-25 designation was adopted by the US Navy in 1962 [1] on introduction of the 1962 United States Tri-Service aircraft designation system. The final units were withdrawn from US service in 1964.[ citation needed] It also served with French Naval Aviation (Aeronavale) from 1953[ citation needed] to 1965. [2]
A total of 339 aircraft were delivered during the 6-year production run. [2][ disputed ] A large number of surplus US Navy aircraft later appeared on the US civil registry, and at least seven were transferred to the French Navy.[ citation needed]
On 7 November 2009, former US Navy HUP-1, BuNo 124925, [11] civil registration number N183YP, [12] collided with high-voltage power lines in Adelanto, California; the subsequent crash and post-crash fire killed all 3 occupants and substantially damaged the aircraft. [12] Operated in association with Classic Rotors, the accident aircraft was the only airworthy example in the world. [11] The National Transportation Safety Board attributed the crash to "The pilot’s failure to maintain clearance from powerlines during en route flight." [12]
For surviving aircraft, hyphenated numbers are original US Army Serial Numbers; six-digit numbers are original US Navy Bureau of Aeronautics (BuAer) Bureau Numbers (BuNo). All 50 H-25A/HUP-3 aircraft transferred from the US Army to the US Navy were given new bureau numbers; 3 aircraft transferred to the Royal Canadian Navy were redesignated, but retained their original US Army serial numbers. [8]
Data from Jane's All The World's Aircraft 1956–57. [39]
General characteristics
Performance
Related development
Aircraft of comparable role, configuration, and era