Hiller YH-32 Hornet

YH-32 Hornet

Hiller YH-32 Hornet on display in Seattle's Museum of Flight
Role	Experimental helicopter
Manufacturer	Hiller Aircraft
First flight	1950
Introduction	1954
Primary users	United States Army United States Navy
Number built	18^[1]^[2]

The Hiller YH-32 Hornet (company designation HJ-1) was an American ultralight helicopter built by Hiller Aircraft in the early 1950s. It was a small and unique design because it was powered by two Hiller 8RJ2B ramjet engines mounted on the rotor blade tips which weigh 13lbs each and deliver an equivalent of 45 h.p. for a total of 90 h.p.^[3] Versions of the HJ-1 Hornet were built for the United States Army and the United States Navy in the early 1950s.

The Hiller Museum identifies the YH-32A, named the Sally Rand, as the first helicopter gunship.

Design and development

The Hiller HJ-1 Hornet was an early attempt to build a jet-powered helicopter using ramjets. Before that there had been experiments with the XH-26 Jet Jeep tip rotor pulse jets. The HJ-1 ramjet tipped rotor propels the rotor and the aircraft. Unlike a conventional helicopter, this mechanically simple design avoids the need for a tail rotor.

Unfortunately, the tip speeds on helicopter rotor blades are subsonic, and ramjets are inefficient at subsonic speeds due to low compression ratio of the inlets. Therefore, the Hornet suffered from high fuel consumption and poor range. Also, the vehicle suffered from low translational speeds, and the ramjet tips were extremely noisy. In the event of power loss, autorotation was found to be difficult due to the drag from the ramjet nacelles.^[4]

The vehicle exhibited powerful lifting capacity, and there was some hope for military uses, but the high noise, poor range, and high night-time visibility of the ramjet flames failed to attract sales.

Operational history

The HJ-1 was evaluated by the United States Army as the YH-32, and the United States Navy as the XHOE-1. In 1957 two YH-32s were modified as the YH-32A for trials as armed helicopters. All the fibreglass cockpit fairings were removed and the tail was modified. The tests were successful in proving the viability of the helicopter as a weapons platform, but due to marginal performance, no further conversions or orders were placed.^[1] Also, versions were sent to the U.S. Army's DRC to be evaluated in one of their contests involving the research and development of a light weight, air droppable helicopter for air rescue and reconnaissance, and for a portable, easily put together, and fuel efficient 1 man observation and transport copter. It was competing against the Jet Jeep and its pulse jets. Overall the YH-32 won out over the Jet Jeep, but the concept was considered obsolete, and later the program was canceled.

Variants

HJ-1: Company designation, one prototype.^[1]
YH-32: United States Army, Similar to HJ.1 with two small v-shaped stabilizers, 14 built (2 prototypes and 12 production aircraft).^[1]
YH-32A: Two YH-32s modified for trials as an armed helicopter.
XHOE-1: Three HJ-1s for evaluation by the United States Navy in 1951.^[2]

Aircraft on display

"XHOE-1 138652 is on display at the Udvar-Hazy Center of the National Air and Space Museum in Chantilly, Virginia^[5]
YH-32 55-4965 "Sally Rand" is on display at the US Army Aviation Museum at Fort Rucker in Ozark, Alabama
YH-32 55-4969 is on display at the Museum of Flight in Seattle, Washington
YH-32 53 4664 and 55-4976 are on display at the Hiller Aviation Museum in San Carlos, California
YH-32 Hornet is on display at Classic Rotors in Ramona, California
YH-32 Hornet is on display at Fantasy of Flight in Polk City, Florida, claimed to be the only flyable example.

Specifications (YH-32)

General characteristics

Crew: two pilots
Length: 23 ft 8 ft (6.9 m)
Rotor diameter: 32 ft ()
Height: 7 ft 10 in (2.4 m)
Disc area: 402 ft² (37.4 m²)
Empty weight: 544 lb (247 kg)
Loaded weight: 1,080 lb (490 kg)
Powerplant: 2 × Hiller 8RJ2B ramjets, 40 lbf (178 N) each

Performance

Maximum speed: 80 mph (129 km/h)
Range: 28 miles (52 km)
Service ceiling: 6,900 ft (2,100 m)
Rate of climb: 700 ft/min (213 m/min)
Disc loading: 2.7 lb/ft² (13 kg/m²)

References

Notes

1 2 3 4 Andrade 1979, p. 121.
1 2 Andrade 1979, p. 195.
↑ "H-32." Flight, 21 March 1958, p. 396.
↑ "Tip-Jet Rotor Helicopters." Aerospaceweb.org, 14 September 2003. Retrieved: 30 January 2012.
↑ "XHOE-1." NASM collections record. Retrieved: 30 January 2012.

Bibliography

Andrade, John. U.S. Military Aircraft Designations and Serials since 1909. Hinckley, UK: Midland Counties Publications, 1979. ISBN 0-904597-22-9.
Apostolo, Giorgio. The Illustrated Encyclopedia of Helicopters. New York: Bonanza Books, 1984. ISBN 0-517-439352.
Display information at Museum of Flight in Seattle, Washington.
Flight page 725 2 November 1956

External links

Wikimedia Commons has media related to Hiller YH-32 Hornet.

United Helicopters/Hiller Helicopters/Hiller Aircraft aircraft

Civil helicopters	UH-12 FH-1100

Military helicopters	HTE-1 OH-23 Raven YOH-5 Ten99

Experimental helicopters	YH-32 Hornet YROE X-18 VZ-1 Pawnee

United States helicopter designations, Army/Air Force and Tri-Service systems

Numerical sequence used by USAAC/USAAF/USAF 1941–present; US Army 1948–1956 and 1962–present; US Navy 1962–present

Main sequence
(1941–1962)

Prefix R-, 1941–1948	R-1 R-2 R-3 R-4 R-5 R-6 R-7 R-8 R-9 R-10 R-11 R-12 R-13 R-14 R-15 R-16

Prefix H-, 1948–1962	H-5 H-6 H-9 H-10 H-11 H-12 H-13/J H-15 H-16 H-17 H-18 H-19 H-20 H-21 H-22 H-23 H-24 H-25 H-26 H-27 H-28 H-29 H-30 H-31 H-32 H-33 H-34 H-35 H-36¹ H-37 H-38¹ H-39 H-40 H-41 H-42 H-43 H-44¹ H-45¹

Main joint sequence
(1962–present)

1962 redesignations	OH-13/UH-13J UH-19 CH-21 OH-23 UH-25 CH-34 CH-37 HH-43

New designations	CH-46/HH-46/UH-46 CH-47 UH-48 XH-49 QH-50 XH-51 HH-52 CH-53/HH-53/MH-53/CH-53E/CH-53K CH-54 TH-55 AH-56 TH-57 OH-58 XH-59 UH-60/SH-60/HH-60/HH-60J YUH-61 XCH-62 YAH-63 AH-64 HH-65 RAH-66 TH-67 MH-68 H-69¹ ARH-70 VH-71 UH-72 H-73 to H-91¹ VH-92

1962 redesignations
reusing old numbers

¹ Not assigned

USN helicopter designations pre-1962

Helicopter, Anti-submarine

Bell	HSL

Sikorsky	HSS-1 HSS-2

Helicopter, Crane

McDonnell	HCH

Helicopter, Observation

Convertawings	HOC

Hiller	HOE

Gyrodyne	HOG

Kaman	HOK

Sikorsky	HOS HO2S HO3S HO4S HO5S

Helicopter, Trainer pre-1948

Sikorsky	HNS

Helicopter, Trainer 1948-1962

Hiller	HTE

Kaman	HTK

Bell	HTL

Helicopter, Transport 1944-1962

Boeing Vertol	HRB

McDonnell	HRH

Piasecki	HRP

Sikorsky	HRS HR2S HR3S

Helicopter, Utility pre-1949

McDonnell	HJD

McDonnell	HJH

Piasecki	HJP

Sikorsky	HJS

Helicopter, Utility 1950-1962

Kaman	HUK HU2K

Bell:	HUL

McCulloch	HUM

Piasecki	HUP

Sikorsky	HUS HU2S

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