The Boeing Vertol XCH-62 (Model 301) was a triple-turbine, heavy-lift helicopter project designed for the United States Army by Boeing Vertol. Approved in 1971, one prototype reached 95% completion before it was canceled in 1975. The prototype was scrapped in 2005.
While the CH-47 Chinook is a large helicopter by American standards, its payload of 28,000 lb (13,000 kg) is dwarfed by the huge Soviet-Russian heavy-lift helicopters such as the Mil Mi-26, with 44,000 lb (20,000 kg) payload, and the experimental Mil V-12, with 55,000 to 88,000 lb (25,000 to 40,000 kg) payload. For a long time Boeing and the US military had an urge to match or top the Mil heavy lifters. In the late 1960s, Boeing came up with designs for machines with broad similarities to the Sea Knight and Chinook, but about twice the size of the Chinook in terms of linear dimensions. Proposed machines included the "Model 227" transport and the "Model 237" flying crane.[1]
The U.S. Department of Defense (DoD) issued a request for proposal (RFP) for a Heavy Lift Helicopter (HLH) in November 1970. On May 7, 1971, the DoD announced the selection of Boeing Vertol to perform the first phase of HLH development.[2] Following award of an Army contract for an HLH prototype in 1973, Boeing did move forward on building an oversized flying crane machine, the "XCH-62". The XCH-62 prototype was in an advanced state of assembly in 1975, being readied for a planned initial flight in 1976.[3] The XT701 engine had passed its 30-hour Prototype Preliminary Flight Rating Test (PPFRT) on March 12, 1975, and then passed a 60-hour Safety Demonstration Test (SDT) on August 4.[4] However, the program was officially canceled on August 1. At the time of cancellation, the prototype was at 95% completion, and it needed about three months of final assembly and checkouts before rollout and installation for pre-flight testing.[5]: 3
Failures in the spiral bevel gearing of the main transmission were experienced in tests because the method of analysis employed had not considered the effect of rim bending. Consequently, new gears with strengthened rims were designed and fabricated. For a more accurate prediction of the load capacity of the gears, an extensive Finite Element Method (FEM) system was developed. The U.S. Army's XCH-62 HLH aft rotor transmission was finally successfully tested at full design torque and speed, but the US Congress cut funding for the program in August 1975.[6] The designers of the Mil Mi-26 avoided similar problems by using a split-torque design in the main rotor transmission.[7]
Subsequent attempts were made to finish the incomplete XCH-62 prototype,[8][9] which had a serial number of 73-22012.[10] In the mid-1980s, the Army, the US National Aeronautics & Space Administration (NASA), and the Defense Advanced Research Projects Agency (DARPA) collaborated on a scheme to finish the XCH-62 for experimental flights, requesting a combined US$71 million in funding through fiscal year 1989.[11] However, Congress declined funding, and the craft remained incomplete.[1] The prototype was moved from a warehouse storage site in Philadelphia, Pennsylvania, floated by barge to Panama City, Florida,[12] and then lifted by a CH-47D Chinook helicopter to the US Army Aviation Museum at Fort Rucker, Alabama on December 8, 1987.[13] The XCH-62 prototype, the largest helicopter ever built in the western countries, was displayed at the US Army Aviation Museum until it was later scrapped in 2005.[10] In 2008, several parts were sent to the Helicopter Museum at Weston-super-Mare (United Kingdom), to be exhibited there.[14]
DesignEdit
The XCH-62 is a tandem rotor helicopter, with four blades on each rotor. Its rotor diameter was to be 92 ft (28 m), fuselage length 89 ft 3 in (27.20 m), and footprint length 162 ft 3 in (49.45 m). The maximum width with blades folded was 29 ft 10 in (9.09 m).[15] The rotor blade had a length was 42 ft (13 m), a chord of 40 in (1,000 mm), and a weight of 750 lb (340 kg).[16]: 2699 The fuselage was mounted high to provide 14 ft (4.3 m) of ground clearance, which let the helicopter taxi over a container for lifting. However, the taxiing requirement was later eliminated because of the helicopter's ability to hover and lift a load, so a second prototype would probably have had only 8 ft 8 in (2.64 m) of ground clearance, which would lower the overall height and reduce the amount of modifications required for the helicopter to fit into hangars.[16]: 2695
The rotorcraft was designed to lift a standard Department of Defense, 8 ft × 8 ft × 20 ft (2.4 m × 2.4 m × 6.1 m) MILVAN container weighing up to 22.4 short tons (20,300 kg).[15] Its widely spaced landing gear would allow it to straddle heavy cargoes such as armored vehicles, and still carry twelve troops in its slender fuselage. Boeing also considered selling a commercial version, the "Model 301".[1] The helicopter was powered by three Allison XT701-AD-700 turboshafts, developed from Allison's 501-M62B engines, which each produced 8,079 shp (6,025 kW) static sea-level power[15] to rotate a shaft at 11,485 rpm. A combiner gearbox converted the power of the three shafts into two transmission shafts turning at 7,976 rpm, leading into forward and aft rotor transmissions that produced 10,620 shp (7,920 kW) at 155.7 rpm.[17] The XCH-62 was designed to be the first helicopter with a fly-by-wireflight control system without a mechanical backup.[15]
^ abc. Archived from the original on August 7, 2007.
^Woodley, David R.; Castle, William S. (October 16–18, 1973). Heavy lift helicopter main engines. National Aerospace Engineering and Manufacturing Meeting. SAE Technical Papers. SAE Technical Paper Series. Vol. 1. Los Angeles, California, U.S.A.: Society of Automotive Engineers (SAE) (published February 1973). doi:10.4271/730920. ISSN 0148-7191.
^"Army revises HLH program, sets competitive prototype tests". R&D News. Army Research and Development. Vol. 16, no. 2. March–April 1975. pp. 4–5. hdl:2027/osu.32435062846985. ISSN 0004-2560.
^Stinger, D.H.; Redmond, W.A. (August 7–10, 1978). Advanced gas turbine for marine propulsion model 570-K. SAE West Coast Meeting, Town & Country. SAE Technical Papers. SAE Technical Paper Series. Vol. 1. San Diego, California, U.S.A.: Society of Automotive Engineers (SAE) (published February 1978). doi:10.4271/780702. ISSN 0148-7191.
^Boeing Vertol Company (April 1980). Heavy lift helicopter — Prototype technical summary (Report). OCLC 227450087.
^"Arrival of landing gear from Boeing Vertol XCH-62 (HLH)". Friends of The Helicopter Museum. Retrieved August 9, 2020.
^ abcde"H.L.H. 1975 flight test projected: Component technology program meeting development goal". Army Research and Development. Vol. 15, no. 1. January–February 1974. pp. 10–11. hdl:2027/msu.31293012265199. ISSN 0004-2560.
^ abcU.S. Senate Research and Development Subcommittee of the Committee on Armed Services (March 18, 1974). Department of the Army: Heavy lift helicopter (Report). Washington, D.C., U.S.A. pp. 2649-2709. hdl:2027/umn.31951d03440242r.
^Schneider, John J. (September 16–19, 1980). The developing technology and economics of large helicopters(PDF). European Rotorcraft and Powered Lift Aircraft Forum (Sixth ed.). Bristol, England, U.K. pp. 3–1 to 3–15. hdl:20.500.11881/1859. OCLC 9813207.
Blackwell, Brendan P. (August 1973). "H.L.H." U.S. Army Aviation Digest. Vol. 19, no. 8. pp. 8–16. hdl:2027/msu.31293108025135. ISSN 0004-2471.
Fries, Gordon H.; Schneider, John J. (December 3–6, 1979). HLH and beyond. SAE Aerospace Meeting. SAE Technical Papers. SAE Technical Paper Series. Vol. 1. Los Angeles, California, U.S.A.: Society of Automotive Engineers (SAE) (published February 1979). doi:10.4271/791086. ISSN 0148-7191. OCLC 5817968838.
"Heavy Lift Helicopter". Military Notes. Military Review. Vol. 51, no. 5. May 1971. p. 95. hdl:2027/uc1.31205012550834. ISSN 1943-1147.
Wilson, Michael (13 July 1972). . Flight International. pp. 44c–47. ISSN 0015-3710. Archived from the original on 5 March 2016.
The initial version of this article was based on a public domain article from Greg Goebel's Vectorsite.
External linksEdit
Wikimedia Commons has media related to Boeing Vertol XCH-62.
XCH-62 Boeing Vertol HLH
August 25, 2023
boeing, vertol, model, triple, turbine, heavy, lift, helicopter, project, designed, united, states, army, boeing, vertol, approved, 1971, prototype, reached, completion, before, canceled, 1975, prototype, scrapped, 2005, hlhrole, heavy, lift, helicoptermanufac. The Boeing Vertol XCH 62 Model 301 was a triple turbine heavy lift helicopter project designed for the United States Army by Boeing Vertol Approved in 1971 one prototype reached 95 completion before it was canceled in 1975 The prototype was scrapped in 2005 XCH 62 HLHRole Heavy lift helicopterManufacturer Boeing VertolStatus Program terminatedPrimary user United States ArmyNumber built 1 never completed Contents 1 Development 2 Design 3 Specifications XCH 62A 4 See also 5 References 5 1 Citations 5 2 Bibliography 6 External linksDevelopment EditWhile the CH 47 Chinook is a large helicopter by American standards its payload of 28 000 lb 13 000 kg is dwarfed by the huge Soviet Russian heavy lift helicopters such as the Mil Mi 26 with 44 000 lb 20 000 kg payload and the experimental Mil V 12 with 55 000 to 88 000 lb 25 000 to 40 000 kg payload For a long time Boeing and the US military had an urge to match or top the Mil heavy lifters In the late 1960s Boeing came up with designs for machines with broad similarities to the Sea Knight and Chinook but about twice the size of the Chinook in terms of linear dimensions Proposed machines included the Model 227 transport and the Model 237 flying crane 1 The U S Department of Defense DoD issued a request for proposal RFP for a Heavy Lift Helicopter HLH in November 1970 On May 7 1971 the DoD announced the selection of Boeing Vertol to perform the first phase of HLH development 2 Following award of an Army contract for an HLH prototype in 1973 Boeing did move forward on building an oversized flying crane machine the XCH 62 The XCH 62 prototype was in an advanced state of assembly in 1975 being readied for a planned initial flight in 1976 3 The XT701 engine had passed its 30 hour Prototype Preliminary Flight Rating Test PPFRT on March 12 1975 and then passed a 60 hour Safety Demonstration Test SDT on August 4 4 However the program was officially canceled on August 1 At the time of cancellation the prototype was at 95 completion and it needed about three months of final assembly and checkouts before rollout and installation for pre flight testing 5 3 Failures in the spiral bevel gearing of the main transmission were experienced in tests because the method of analysis employed had not considered the effect of rim bending Consequently new gears with strengthened rims were designed and fabricated For a more accurate prediction of the load capacity of the gears an extensive Finite Element Method FEM system was developed The U S Army s XCH 62 HLH aft rotor transmission was finally successfully tested at full design torque and speed but the US Congress cut funding for the program in August 1975 6 The designers of the Mil Mi 26 avoided similar problems by using a split torque design in the main rotor transmission 7 Subsequent attempts were made to finish the incomplete XCH 62 prototype 8 9 which had a serial number of 73 22012 10 In the mid 1980s the Army the US National Aeronautics amp Space Administration NASA and the Defense Advanced Research Projects Agency DARPA collaborated on a scheme to finish the XCH 62 for experimental flights requesting a combined US 71 million in funding through fiscal year 1989 11 However Congress declined funding and the craft remained incomplete 1 The prototype was moved from a warehouse storage site in Philadelphia Pennsylvania floated by barge to Panama City Florida 12 and then lifted by a CH 47D Chinook helicopter to the US Army Aviation Museum at Fort Rucker Alabama on December 8 1987 13 The XCH 62 prototype the largest helicopter ever built in the western countries was displayed at the US Army Aviation Museum until it was later scrapped in 2005 10 In 2008 several parts were sent to the Helicopter Museum at Weston super Mare United Kingdom to be exhibited there 14 Design EditThe XCH 62 is a tandem rotor helicopter with four blades on each rotor Its rotor diameter was to be 92 ft 28 m fuselage length 89 ft 3 in 27 20 m and footprint length 162 ft 3 in 49 45 m The maximum width with blades folded was 29 ft 10 in 9 09 m 15 The rotor blade had a length was 42 ft 13 m a chord of 40 in 1 000 mm and a weight of 750 lb 340 kg 16 2699 The fuselage was mounted high to provide 14 ft 4 3 m of ground clearance which let the helicopter taxi over a container for lifting However the taxiing requirement was later eliminated because of the helicopter s ability to hover and lift a load so a second prototype would probably have had only 8 ft 8 in 2 64 m of ground clearance which would lower the overall height and reduce the amount of modifications required for the helicopter to fit into hangars 16 2695 The rotorcraft was designed to lift a standard Department of Defense 8 ft 8 ft 20 ft 2 4 m 2 4 m 6 1 m MILVAN container weighing up to 22 4 short tons 20 300 kg 15 Its widely spaced landing gear would allow it to straddle heavy cargoes such as armored vehicles and still carry twelve troops in its slender fuselage Boeing also considered selling a commercial version the Model 301 1 The helicopter was powered by three Allison XT701 AD 700 turboshafts developed from Allison s 501 M62B engines which each produced 8 079 shp 6 025 kW static sea level power 15 to rotate a shaft at 11 485 rpm A combiner gearbox converted the power of the three shafts into two transmission shafts turning at 7 976 rpm leading into forward and aft rotor transmissions that produced 10 620 shp 7 920 kW at 155 7 rpm 17 The XCH 62 was designed to be the first helicopter with a fly by wire flight control system without a mechanical backup 15 Specifications XCH 62A Edit Data from America s heavy lift helicopter 18 General characteristicsCrew 5 pilot copilot flight engineer load controlling crewman and crew chief 15 Capacity 12 troops 16 2709 Length 87 ft 3 in 26 59 m overall fuselage length Height 32 ft 3 in 9 83 m to top of pylon Empty weight 59 580 lb 27 025 kg Gross weight 118 000 lb 53 524 kg Powerplant 3 Allison T701 AD 700 turboshaft 8 080 hp 6 030 kW each Main rotor diameter 2 92 ft 0 in 28 04 m Main rotor area 13 260 sq ft 1 232 m2 Performance Maximum speed 145 kn 167 mph 269 km h with external load Combat range 150 nmi 170 mi 280 km Ferry range 1 500 nmi 1 700 mi 2 800 km See also EditAerial craneRelated development Boeing CH 47 Chinook Boeing Vertol BV 347Aircraft of comparable role configuration and era Mil Mi 10 Sikorsky S 73Related lists List of helicoptersReferences EditCitations Edit a b c Greg Goebel s Vectorsite Archived from the original on August 7 2007 Woodley David R Castle William S October 16 18 1973 Heavy lift helicopter main engines National Aerospace Engineering and Manufacturing Meeting SAE Technical Papers SAE Technical Paper Series Vol 1 Los Angeles California U S A Society of Automotive Engineers SAE published February 1973 doi 10 4271 730920 ISSN 0148 7191 Army revises HLH program sets competitive prototype tests R amp D News Army Research and Development Vol 16 no 2 March April 1975 pp 4 5 hdl 2027 osu 32435062846985 ISSN 0004 2560 Stinger D H Redmond W A August 7 10 1978 Advanced gas turbine for marine propulsion model 570 K SAE West Coast Meeting Town amp Country SAE Technical Papers SAE Technical Paper Series Vol 1 San Diego California U S A Society of Automotive Engineers SAE published February 1978 doi 10 4271 780702 ISSN 0148 7191 Boeing Vertol Company April 1980 Heavy lift helicopter Prototype technical summary Report OCLC 227450087 XCH 62 page on Globalsecurity org Smirnov G Multiple Power Path Nonplanetary Main Gearbox of the Mi 26 Heavy Lift Transport Helicopter Vertiflite March April 1990 pp 20 23 Meantime back at Boeing Technology update Popular Mechanics Vol 158 no 3 September 1982 p 173 ISSN 0032 4558 Champion choppers Technology update Popular Mechanics Vol 162 no 4 April 1985 p 69 ISSN 0032 4558 a b XCH 62 destruction pictures cause a stir Aero News Network November 20 2005 Retrieved August 9 2020 Wilson George C December 13 1984 Army seeks to test canceled helicopter Citizens Voice Washington D C U S A The Washington Post ISSN 1070 8626 via Newspapers com From drawing board to museum The nation Orlando Sentinel December 9 1987 p A 10 ISSN 0744 6055 via Newspapers com Copter carry National dateline Pensacola News Journal December 9 1987 p 4A OCLC 54453673 via Newspapers com Arrival of landing gear from Boeing Vertol XCH 62 HLH Friends of The Helicopter Museum Retrieved August 9 2020 a b c d e H L H 1975 flight test projected Component technology program meeting development goal Army Research and Development Vol 15 no 1 January February 1974 pp 10 11 hdl 2027 msu 31293012265199 ISSN 0004 2560 a b c U S Senate Research and Development Subcommittee of the Committee on Armed Services March 18 1974 Department of the Army Heavy lift helicopter Report Washington D C U S A pp 2649 2709 hdl 2027 umn 31951d03440242r Schneider John J September 16 19 1980 The developing technology and economics of large helicopters PDF European Rotorcraft and Powered Lift Aircraft Forum Sixth ed Bristol England U K pp 3 1 to 3 15 hdl 20 500 11881 1859 OCLC 9813207 Wilson Flight International 13 July 1972 p 47 Bibliography Edit Blackwell Brendan P August 1973 H L H U S Army Aviation Digest Vol 19 no 8 pp 8 16 hdl 2027 msu 31293108025135 ISSN 0004 2471 Fries Gordon H Schneider John J December 3 6 1979 HLH and beyond SAE Aerospace Meeting SAE Technical Papers SAE Technical Paper Series Vol 1 Los Angeles California U S A Society of Automotive Engineers SAE published February 1979 doi 10 4271 791086 ISSN 0148 7191 OCLC 5817968838 Heavy Lift Helicopter Military Notes Military Review Vol 51 no 5 May 1971 p 95 hdl 2027 uc1 31205012550834 ISSN 1943 1147 Wilson Michael 13 July 1972 America s heavy lift helicopter Flight International pp 44c 47 ISSN 0015 3710 Archived from the original on 5 March 2016 The initial version of this article was based on a public domain article from Greg Goebel s Vectorsite External links Edit Wikimedia Commons has media related to Boeing Vertol XCH 62 XCH 62 Boeing Vertol HLH Retrieved from https en wikipedia org w index php title Boeing Vertol XCH 62 amp oldid 1147503173, wikipedia, wiki, book, books, library,
