Hiller YH-32 Hornet

https://en.wikipedia.org/wiki/Hiller_YH-32_Hornet

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. 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.

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.

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.

Role
Experimental helicopter

Manufacturer
Hiller Aircraft

First flight
1950

Introduction
1954

Primary users
United States Army
United States Navy

Number built
18

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.

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.

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)





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