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The Westland Belvedere HC.1 was the Royal Air Force’s first ‘heavy-lift’ helicopter, but it had a difficult ‘birth’, which left it with a less than optimal design, a short production run, and an incident-prone Service career. The Bristol Aircraft Company had built the Royal Air Force’s first British-designed helicopter, the Sycamore HR 12 (entered service in 1952), and it seemed logical, therefore, that the company would tender for Specification E.4/47 for a ten-place twin-engined helicopter. After a lot of design effort and wind-tunnel testing, the first test example, the Type 173, emerged with 2 x 575hp Alvis Leonides piston-engines and two three-bladed wooden Bristol Sycamore rotor heads, one at either end of a tubular fuselage. This prototype, serial XF785, was flown at the 1952 Society of British Aircraft Constructors Show (as it was then known) at Farnborough. This was, of course, the tragic airshow where the test pilot, John Derry, and his flight test observer, Anthony Richards, were killed in the crash of the DH.110 prototype, with 28 spectators being killed by debris.

After trials of the big Bristol helicopter by both the Royal Navy and the Royal Air Force, no orders were forthcoming, and a major rework was undertaken. Two parallel designs emerged, one was a proposal to the Royal Navy for a long-range, homing torpedo-equipped sub-hunter (the Type 191, and a similar design for the Royal Canadian Navy, the Type 193); ultimately, both of these proposals failed – there were many political undercurrents to the Canadian decision. However, interest was once again being shown by the RAF, since the Leonides were to be replaced by powerful turboshaft engines and a new rotor head and blades were being developed, along with distinctive compound anhedral rear stabilizing fins. It was at this point that life became really complicated.

In 1957, the U.K. Government had issued a radical (and some say, disastrous) Defence White Paper. Duncan Sandys, the Minister concerned cancelled almost every fighter project – except the P.1 which became the Lightning – and focused on missiles and rockets (he was a fanatic about rockets!). Westland, like Bristol a West of England company, was selected by the Government to take over the whole of the British helicopter business (a decision that would come back to haunt later British Governments); so, in March, 1960, Westland bought the Bristol Helicopter Unit for 5 million Westland shares and £2 million cash (some 10% of the value of the company). Now operating as the Bristol Helicopter Division of Westlands, out of the former Bristol plant at Mixon, Weston-super-Mare, the next task was to use the three cancelled Type 191 airframes to develop a viable heavy-lift helicopter for the RAF. A series of pre-production standard machines were sent to RAF Odiham, to the west of London, where much of the Royal Air Force’s helicopter expertise was centered. The first five prototypes had wooden rotor blades and manual controls; XG447, the first to this interim standard, made its initial flight on the 5th July, 1958, and a production batch of 26 was ordered shortly afterwards. Metal rotor blades and hydraulically boosted flying controls were to come later (the mechanism for these was fitted underneath the cockpit floor, in a distinctive ‘chin bulge’).

The Westland Belvedere HC.1 as it was now named (inevitably called the ‘Bevelled Gear’ by workers at the Mixon plant) had an all-metal fuselage of ovoid cross-section with a 1,465 (eventually, 1,685) shp Napier Gazelle NGa2 turboshaft at each end. These were derated to approximately 910 shp and connected by a synchronizing shaft, so that in the event of an engine failure the other engine could be boosted beyond its ‘normal’ rating and drive both sets of rotors. This automatic process took approximately two seconds, and it is said that the only way a pilot could tell it had happened was if he monitored the relevant cockpit gauges! The presence of the engine and transmission immediately behind the cockpit meant that access was via a curving narrow gangway to the port side of the engine, and that the two pilots had no easy means of reaching the third member of the crew in the fuselage during flight. Similarly, the rear engine blocked any possibility of fitting a rear-loading door to the design, something that would have added great utility to the Belvedere. Indeed, the fact that the front wheels of the aircraft were self-castoring, and quite tall (a relic of the naval design, so that homing torpedoes could be easily loaded) made for a main fuselage door that was no less than four feet off the ground; not ideal for a machine that had ‘re-supply of forces in the field’ as one of its main tasks.

The Belvedere Trails Unit quickly settled in to the swing of things, which included showing that a fully laden Landrover and trailer could be swung from the central, external hook (the Belvedere could also carry an MGR-1 ‘Honest John’ battlefield missile, or a Bristol Bloodhound SAM easily); one of the most impressive loads ever carried was on 28th April, 1962 when the avant-garde metal spire designed by Sir Basil Spence was lifted into place to ‘top out’ his new Coventry Cathedral, built alongside the ruins of the Mediaeval one which was destroyed in WW2.

No ‘first tour’ helicopter pilots were posted to the Belvedere Trials Unit, as the big helicopter was a bit of a handful. To start the twin turboshafts, you had to select the appropriate AVPIN unit then fire a cartridge starter, which compressed/ignited the volatile AVPIN (isopropyl nitrate or 2-propyl nitrate). AVPIN is a mono-propellant, which requires no oxygen to ignite it. It burns with a fierce, invisible flame, and can be classified as a low-grade explosive. A few of the early jets, such as the Gloster Javelin, and some Hawker Hunters, also used AVPIN and there were many fires and accidents caused by this compound; another problem was the fact that a major byproduct of AVPIN combustion is gaseous hydrocyanic acid (HCN), which caused streaming eyes and throat problems! The Trials Unit was formed into No. 66 Squadron (motto, Cavete praemonui,”Beware, I have warned”), which was sent overseas, shortly after demonstrating their prowess by unloading Landrovers and troops onto barges floating on the River Thames during the 1961 Lord Mayor’s Show! The Belvedere was also used by No. 26 and 72 Squadrons, which went to Aden (RAF Khormaksar) and Germany (RAF Gutersloh) respectively.

Great Britain was not in any ‘declared’ wars in the 1960s, but was heavily involved in actions against rebels in the south of the Arabian Peninsula, and in an armed confrontation with the Republic of Indonesia, during 1962-4, in Brunei. Sorties were flown from Labuan in Borneo in support of detachments of Gurkha and other British troops in the jungle. I am told that the priorities in loads were a) mail b) beer c) food – in that order! What with flying in replacements and performing ‘casevac’ sorties the Belvederes were kept very busy. They could even lift out downed Westland Whirlwind helicopters (licence-built Sikorsky S-55) from the jungle, when the engine and rotor blades had been removed. The jungle was certainly unforgiving when it came to aircraft crashes; in May, 1962, a Belvedere went down near Long Pai Sia in Brunei, killing all 16 on board, including three leading members of No 22 Special Air Services Regiment.

Meanwhile 26 Squadron were deeply engaged in supporting British troops (including the Parachute Regiment, Royal Marines, and 3rd Royal Anglian Regiment) in and around Aden, in their actions against the Front for the Liberation of Occupied South Yemen (FLOSY) and the National Liberation Front (NLF) and other groups; the helicopters had to be armed when they were flying resupply and support missions over the Radfan Mountains north of Aden. Both GPMG and Bren .303″ machineguns could be fitted in the waist door, but No. 26 Squadron had no gunners! Consequently, No. 8 Squadron, RAF, who were using their large Avro Shackleton maritime patrol aircraft (think, 'grandson of Lancaster') in an unconventional ‘land attack’ role in the Aden territory, loaned some of their air gunners to No. 26.

There were some difficulties with maintenance; changing a set of rotor blades was a skilled job involving a team of technicians, as was balancing the synchonizing shaft and changing the slip rings on the rotor head (associated with the rotor blade strain gauges). Sadly, there were several fatal crashes – on 30th July, 1962, XG465 (“J” of 72 Squadron, RAF) suffered an engine failure and a rotor blade impacted the fuselage; this Belvedere crashed northwest of RAF Gutersloh in Germany, with all six occupants onboard being killed. The Belvedere could carry 8 to 12 stretcher cases (plus up to three medical attendants), 19 fully-equipped troops or 6,000lb of cargo internally, but despite Westland taking a full-page advertisement in ‘Flight’ following the 1962 RAF ‘Exercise Spearpoint’ in support of the British Army, saying that “this demonstrated the versatility of the Belvedere and the need for many helicopters of this class to increase the mobility and communications of forward battle troops”, the Ministry of Defence was not moved. Neither was the Australian Government, despite the fact that their Army was in favour of purchasing the Belvedere. Also, the attempt to market a civilian version, the Type 192C, which was 4 inches wider than the military version and could carry 17 passengers in ‘VIP class’ or 27 in economy, was a failure, despite the fact that a ‘loaned’ Belvedere was flown between Battersea Heliport in the center of London and Paris in 1 hour and 41 minutes, attaining a speed of 154 mph, as the fuel burnt off. British European Airways were not sufficiently impressed, and no civil orders ensued.

Sadly, the last example of the RAF’s first twin-engined, twin-rotor helicopter left the production line in June, 1962. The type was withdrawn from RAF service on the 17th March, 1969, with a mass flypast by helicopters of No. 66 Squadron, which then disbanded. They had been supporting British forces in the jungles of Malaysia, from their base at RAF Seletar on the island of Singapore. As an aside, it is a quirk of aviation history that no less than FIVE RAF types, the Westland Belvedere, the Blackburn Beverley, the Supermarine Spitfire, the Bristol Beaufighter and the de Havilland Mosquito should ALL have performed their last RAF operational flights from Seletar!

Despite such a small production run, no less than three airframes have made it into preservation (along with parts of a fourth). The Helicopter Museum at Weston-super-Mare – a marvelous facility, founded by my old BAPC colleague, Elfan ap Rees – has XG452 under restoration, and holds the nose section of XG462, as well. As you would expect, the RAF Museum, London has XG474 on display, one of the very last Belvederes, and one which took part in the ‘disbandment’ flypast by 66 Squadron at Seletar. Here you can see probably the most unusual of the three survivors, XG454, an aircraft with an unfortunate history. It was the seventh of the Belvederes, built to ‘pre-production’ standard and delivered on the 17th October, 1960 to the Belvedere Trials Unit at Odiham. Unfortunately, it crashed the very next month, although repairs were successful and it was re-issued to the BTU in March, 1961. It only lasted another 5 months, however, as it crashed – again – on the 30th August! This was the end of its flying days, as it became an Instructional Airframe, with the serial number ’8366M’. Eventually, it was sent to the Museum of Science and Industry at Manchester, where you can see it on display in their beautiful Victorian Market Hall building (a difficult place to exhibit large objects to advantage in).

The Westland Belvedere HC.1 – a twin-engined rotorcraft ahead of its time

http://peoplesmosquito.org.uk

Extended (Optional)

Originally posted to shortfinals on Tue Feb 04, 2014 at 04:10 PM PST.

Also republished by Kossack Air Force, Aviation & Pilots, History for Kossacks, SciTech, and Helicopters and Rotorcraft.

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