Bristol Type 192 Belvedere

https://en.wikipedia.org/wiki/Bristol_Belvedere

The Bristol Type 192 Belvedere was a British twin-engine, tandem rotor military
helicopter built by the Bristol Aeroplane Company. It was designed by Raoul
Hafner for a variety of transport roles including troop transport, supply
dropping and casualty evacuation. It was operated by the Royal Air Force (RAF)
from 1961 to 1969. The Belvedere was Britain's only tandem rotor helicopter to
enter production, and one of the few not built by Boeing or Piasecki.

The Belvedere was based on the Bristol Type 173 10-seat (later 16-seat) civilian
helicopter which first flew on 3 January 1952. The 173 project was cancelled in
1956 and Bristol spent time on the Type 191 and Type 193 to Royal Navy and Royal
Canadian Navy specifications. These two naval variants were cancelled, but the
RAF expressed an interest in the aircraft and the Type 192 "Belvedere" was
created. Three Type 191 airframes were almost complete when the order was
cancelled, but they were used to aid the development of the Type 192. The first
two were used as test rigs for the new Napier Gazelle engines and the third was
used for fatigue tests.

The first Type 192 prototype XG447 flew on 5 July 1958 with tandem wooden rotor
blades, a completely manual control system and a castored, fixed quadricycle
undercarriage. From the fifth prototype, the rotors fitted were all-metal,
four-bladed units. Production model controls and instruments allowed night
operations. The prototype machines had an upwards-hinged main passenger and
cockpit door, which was prone to being slammed shut by the downwash from the
rotors. This was replaced by a sliding door on the later aircraft.

Twenty-six Belvederes were built, entering service as the Belvedere HC Mark 1.
The Belvederes were originally designed for use with the Royal Navy but were
later adapted to carry 18 fully equipped troops with a total load capacity of
6,000 lb (2,700 kg). The two rotors were synchronised through a shaft to prevent
blade collision, allowing the aircraft to operate through only one engine in the
event of an emergency. In that case, the remaining engine would automatically
run up to double power to compensate.


Role
Cargo helicopter

Manufacturer
Bristol Aeroplane Company

Designer
Raoul Hafner

First flight
5 July 1958

Introduction
1961

Retired
1969

Primary user
Royal Air Force

Number built
26

Developed from
Bristol Type 173

The first prototype Belvedere went to the Belvedere Trials Unit at RAF Odiham,
which was subsequently reformed as No. 66 Squadron RAF in 1961. Engine starter
problems caused trouble early on but operational deployment continued. The
prototype saw service in Europe, Africa, Southern Arabia and Borneo. XG447 was
broken up at Boscombe Down on 7 August 1966.

As well as 66 Squadron, the type was deployed to 72 Squadron in 1961 and 26
Squadron in 1962, all at RAF Odiham. 26 Squadron later transferred to RAF
Khormaksar where it disbanded in November 1965. The helicopters were transferred
by HMS Albion to Singapore to join 66 Squadron until the squadron was disbanded
in 1969. 72 Squadron kept its Belvederes until August 1964 when it exchanged
them for Westland Wessex.

The RAF Belvederes were involved in combat in Aden Emergency and Borneo (during
the Indonesia–Malaysia confrontation).

Specifications (Belvedere HC.1)

General characteristics
Crew: 3
Capacity:
19 fully equipped troops or
12 stretchers with two seated wounded and a medical attendant

Payload: 6,000 lb (2,700 kg) internal or slung
Length: 54 ft 4 in (16.56 m)
Rotor diameter: 48 ft 11 in (14.9 m)
Height: 17 ft 0 in (5.18 m)
Disc area: 3,270 sq ft (303.9 m²)
Empty weight: 11,350 lb (5,159 kg)
Max. takeoff weight: 19,000 lb (8,600 kg)
Fuel capacity: 560 imp gal
Powerplant: 2 × Napier Gazelle turboshaft, 1,465 hp (1,092 kW) each

Performance
Cruise speed: 138 mph (120 knots, 222 km/h) maximum
Range: 460 mi (400 nmi, 720 km) standard tankage
Service ceiling: 12,000 ft (3,660 m)
Rate of climb: 850 ft/min (4.3 m/s)
Vertical climb rate: 440 ft/min




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