Bristol Bloodhound

"surface-to-air missile" redirects here. For the earlier aircraft, see Bristol Type 84 Bloodhound.

colspan="2" Template:WPMILHIST Infobox style \| Bloodhound Mk 2
colspan="2" Template:WPMILHIST Infobox style \| File:Bloodhound SAM at the RAF Museum.jpg A Bloodhound missile at the RAF Museum, Hendon, London.
Type	SAM
Place of origin	United Kingdom
colspan="2" Template:WPMILHIST Infobox style \| Service history
In service	1958 (MK 1)/1964 - 1991
Used by	RAF, RAAF, Switzerland, Sweden, Singapore
Wars	-
colspan="2" Template:WPMILHIST Infobox style \| Production history
Designed	1950s
Manufacturer	Bristol Aeroplane Co.
Number built	783
Variants	Mk 1, Mk 2
colspan="2" Template:WPMILHIST Infobox style \| Specifications
Weight	2,270 kg
Length	8.46 m (with booster)
Diameter	54.6 cm (body)

Warhead	Continuous-rod warhead
Detonation mechanism	Proximity fuse

Engine	2 x Ramjet, 4 x solid fuel booster
Wingspan	2.83 m
Operational range	85 km
Speed	Mach 2.7
Guidance system	Semi-active radar
Steering system	Control surfaces
Launch platform	Fixed installation

The Bristol Bloodhound is a British surface-to-air missile developed during the 1950s as the UK's main air defence weapon, and was in large-scale service with the Royal Air Force (RAF) and the forces of four other countries. The Bloodhound Mk. I entered service in December 1958 and the last Mk. II missile squadron stood down in July 1991, although Swiss examples remained operational until 1999.

History

The Stage Plan

After the end of World War II UK air defences were allowed to fall into disuse, the assumption being it would be a decade before another war started. However, the Soviet atomic bomb test of 1949 forced a re-evaluation of that policy, and UK defence planners started studying the problems of building a more integrated air defence network than the patchwork of WWII expediencies. The Cherry Report called for a reorganization of existing radars under the ROTOR project along with new control centres to better coordinate fighters and anti-aircraft guns. This was strictly a stop-gap measure however; over a longer term it would require deployments of new long-range radars in place of the Chain Home systems from the war, command and control sites able to survive a nuclear attack, interceptors of ever-increasing performance, and anti-aircraft missiles and guns to provide a last-ditch defence.

The missile portion was the newest and least understood technology. In order to deploy quickly and gain experience with these systems, the "Stage Plan" was developed. "Stage 1" called for missiles with a range of only 20 miles with capabilities against subsonic or low-supersonic attacking aircraft, which were assumed to be at medium or high altitudes. The Stage 1 missile would be used to protect the V bomber bases in the UK, as well as the British Army in the field.^[1] The Stage 1 missile would be later replaced with a much higher-performance and longer-range "Stage 2" system in the 1960s, which would have capability against supersonic targets at longer ranges.^[1]

Two entries were accepted for the original Stage 1 proposal, an already-started project from English Electric's under the name "Red Shoes",^[2] and Bristol's proposal under "Red Duster".^[3] Bristol's efforts were fairly similar to EE's in most ways, although it was somewhat less mobile while offering somewhat better range. Ferranti would develop the radar and guidance system for both. Bristol was awarded a development contract in 1949, referring to it as Project 1220.^[3]

Development

Bristol's airframe design developed rapidly. The main missile is a long cylinder of magnesium frames and aluminium alloy skin with a prominent ogive nose cone at the front and some boat-tailing at the rear. Small aluminium-covered wooden cropped-delta wings are mounted mid-point, providing pitch and roll control by pivoting in unison or independently. Two smaller rectangular fixed surfaces were mounted in-line with the main wings, almost at the rear of the missile.

Two Bristol Thor ramjet engines were mounted, above and below the wing. Four "Gosling" solid-fuel rockets were wrapped around the fuselage, lying above and below the wings on either side. The Goslings mounted rather large fins of their own, which aided separation on burnout. On launch the Goslings were fired, shearing off the restraining bolts and boosting the missile to over Mach 2 before burning out after four seconds. The Thors ignited in-flight once up to operational speed, and sustained the speed for up to 80 seconds.

Guidance was semi-automatic, with the targets initially identified by existing early warning radar sites and then handed off to the Bloodhound sites for local detection and attack. This was handled by the truck-mounted Type 83 "Yellow River" pulse radar system that could be fairly easily jammed and was vulnerable to ground 'clutter', thus degrading low-level capability.

In 1952 the design was accepted by the Combined United Kingdom/Australia Committee for Trials. A series of test vehicles were developed and flown in Wales, called eXperimental Test Vehicles or XTV, with XTV.1 to XTV.5 being used to develop the aerodynamics, propulsion and guidance systems. After the XTV series completed testing moved to the Woomera range in South Australia in mid-1953, with the XRD (eXperimental Red Duster) which was more or less the definitive Bloodhound I. These proved very disappointing due to ramjet problems, which were traced to the use of a flare as an ignition source inside the engine. This was replaced with an igniter design from the National Gas Turbine Establishment and the problems were quickly sorted out. Firings against Jindivik target aircraft started in 1956.^[3]

By this time English Electric's solid-fueled Red Shoes, now known as the English Electric Thunderbird, was proving successful and the British Army dropped their orders for the Bloodhound in favor of the Thunderbird.

The Mk 1 entered British service in 1958, and was selected for the RAAF in November of that year. Deployment of the Bloodhound Mk. I began in 1958, initially to provide protection for the RAF's V-bomber bases. Australian deployments started in January 1961.

Although the Bloodhound was successful technically, Government auditors found that Ferranti had made far larger profits than projected from the Bloodhound I contract. Sir John Lang chaired an inquiry into the matter. Sebastian de Ferranti agreed to pay back £4.25 million to the government.^[4]

Further developments

By 1955 it appeared that the Stage 2 missiles were too far beyond the state of the art to be able to enter service before the Thunderbird and Bloodhound would already be obsolete. Meanwhile the much improved continuous wave radar systems being developed for the same project, Green Sparkler, were progressing quite nicely. In order to address the timing problems, interim Stages were added. "Stage 1½" combined a slightly upgraded Thunderbird with Green Sparkler, while "Stage 1¾" would replace the Bloodhound outright with a new missile design known as "Blue Envoy" with 150 mile range.^[5]

In 1957 the entire Stage concept was abandoned as part of the 1957 Defence White Paper. Bristol engineers sharing a taxi with their Ferranti counterparts hatched a new plan to adapt the Blue Envoy ramjets and radars to a lengthened Bloodhound, and submitted this for study. The proposal was accepted, producing the Bloodhound Mk. II.

The Mk. II featured a more powerful Thor engine based on changes investigated in Blue Envoy, along with a stretched fuselage that increased fuel storage. These changes dramatically extended range from about 35 km to 80 km, pushing the practical engagement distance out to about 50 km (although detected at a longer range, the missile takes time to travel to its target, during which it approaches the base).^[6]

The Mk. II was guided by either the Ferranti Type 86 Firelight radar for mobile use, or the larger fixed-emplacement Marconi Type 87 "Scorpion". In addition to its own illumination and tracking antennas, the Scorpion also added one of the receiver antennas out of a missile body on the same frame. This antenna was used to determine what the missile's own receiver was seeing, which was used for jamming detection and assessment. The new radars eliminated problems with ground reflections, allowing the missile to be fired at any visible target, no matter how close to the ground. Combined with the new engines, the Mk. II had an extended altitude performance between 150 ft and 65,000 ft.

The use of a CW radar presented a problem for the semi-automatic guidance system. Continuous wave radars rely on the Doppler effect to detect moving targets, comparing returned signals to the reference signal being broadcast. However in the Bloodhound's case the missile was moving away from the reference signal as fast, or faster than, the target would be approaching it. The missile would need to know the velocity of the target as well as its own airspeed in order to know what frequency to look for, but this information was known only to the radar station on the ground, the missile did not broadcast any signals of its own. To solve this problem the radar site also broadcast an omnidirectional reference signal that was shifted to the frequency that the missile's receiver should be looking for, taking into account both the target and missile speed. Thus the missile only had to compare the signal from its nose-mounted receiver with the signal from the launch site, greatly simplifying the electronics.^[7]

Many of the calculations in terms of lead, frequency shifting, and pointing angles for the radars were handled by the custom-built Ferranti Argus computer. This machine would later go on to be a successful industrial control computer which was sold all over Europe for a wide variety of roles.

The Mk. II started testing in 1963 and entered RAF service in 1964. Unlike the Mk. I that had limited performance advantages compared to the Thunderbird, the Mk. II was a much more formidable weapon with capabilities against Mach 2 aircraft at high altitudes. Several new Bloodhound bases were set up for the Mk. II, and some of the Mk. I bases were updated to host the Mk. II.

There was an export version planned, Bloodhound 21, that had less sophisticated electronic countermeasures equipment.^[8] The planned Mk. III (also known as RO 166) was a nuclear warhead-equipped Mk. II with a longer range (around 75 miles) achieved with improved ramjet engine and larger boosters. The project, one of several adaptations of existing British missiles to carry tactical nuclear devices, was cancelled in 1960. Mk. IV was a cancelled mobile version, based on Swedish field army experience.

Operational deployments

File:Bloodhound missile - Parafield.jpg

Bloodhound as used by the RAAF from 1963 with No.30 Squadron in Darwin, Australia

File:Bloodhound Mk.II SAM.jpg

Bloodhound of the Republic of Singapore Air Force.

The initial Bloodhound Mk. I deployment consisted of eight missile sites; Dunholme Lodge, Watton, Marham, Rattlesden, Woolfox Lodge, Carnaby, Warboys, Breighton and Mission with a trial site at RAF North Coates.^[9]

Australian deployments started with No. 30 Squadron at RAAF Base Williamtown in January 1961. A detachment formed in Darwin in 1965. By 1968, the Bloodhound Mk. I missiles were obsolete, and both elements of the squadron had been disbanded by the end of November 1968.

Swiss deployments started in 1964, and by 1967 six sites were operational with a total of nine firing units. These remained operational until 1999 when they were removed from service, and the Gubel site was declared a national historical property.^[10]

After the RAF passed the nuclear deterrent role to the Royal Navy in 1970, all Bloodhound systems within the UK were withdrawn and either stored or transferred to RAF Germany for airfield defence with No. 25 Squadron. The possibility of low-level sneak attack by bombers or cruise missiles led to a reappraisal of UK air defences, resulting in No. 85 Squadron forming at West Raynham on 18 December 1975.

With deployment of the Rapier missile to Germany, Bloodhounds were returned to England in 1983 and were in operation at three additional airfields, Barkston Heath, Wyton and Wattisham. These installations used the mobile Type 86 radars of their German deployments, but mounted them on a 30 foot tower to improve visibility and reduce ground reflections. In 1990 as the cold war wound down the remaining missiles were concentrated at West Raynham and Wattisham with plans to operate them until 1995, but these were later removed in 1991.

In South East Asia, the Bloodhound was deployed with the RAF No. 65 Squadron based out of RAF Seletar, Singapore as part of the RAF Far East Air Force. With the withdrawal of British forces announced in 1968, Singapore bought the entire Bloodhound assets of the No. 65 Squadron and established the Singapore Air Defence Command's 170 Squadron. Singapore's Bloodhound Mk. II missiles were sold on to Burma in 1994.^[11]

Variants

Mk I

Length : 7.7 m
Launch Weight : 2,000 kg
Range : 30 km
Max. Speed : Mach 2.2
Propulsion
- Main : 2 x Thor ramjet engines
- Booster : 4 Gosling booster rockets

File:Bloodhound thor arp 750pix.jpg

One of the two Thor ramjet engines of a Bloodhound missile (not a model)

Mk II

Length : 8.45 m
Launch Weight :
Range : 85 km
Max. Speed : Mach 2.7
Propulsion
- Main : 2 x Thor ramjet engines (Improved)
- Booster : 4 Gosling booster rockets

The acceleration of the Mk. II can be gauged from the data on an information board at the Bristol Aeroplane Company Museum at Kemble Airfield, Kemble, Gloucestershire, where a complete Bloodhound can be seen. The Mark of Bloodhound this data refers to is not given but is presumably the Mark II since the top speed of the Mk. I is Mach 2.2:
"By the time the missile has just cleared the launcher it is doing 400 mph. By the time the missile is 25 feet from the launcher it has reached the speed of sound (around 720 mph). Three seconds after launch, as the four boost rockets fall away, it has reached Mach 2.5 which is roughly 1800 mph"

Mk III

The planned Mk III (also known as RO 166) was a nuclear warhead equipped Mark II with a longer range (around 75 mile) achieved with improved Ramjet engine and bigger boosters. The project, one of several adaptations of existing British missiles to carry tactical nuclear devices, was cancelled in 1960.