Bristol Bloodhound Mk 1 and Mk 2
Surface to Air Missile based at North Coates, Woodhall Spa and Dunholme Lodge in Lincolnshire for protection of the Lincolnshire V Bomber airfields
Bloodhound Mk 1 North Coates 1958 with Duke of Edinburgh 2nd from right
The Bristol Bloodhound was an impressive and very advanced surface to air missile for the immediate post war era, particularly the Mk II. The development by Bristol, who had limited experience of this technology, in the time available was an achievement of considerable merit. That can be said for other manufacturers and research establishments associated with the project and particularly those involved with the supporting radar.
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Background and Development
At the conclusion of WW2 the UK air defences were neglected on the assumption by the then Labour government that it would be at least a decade before another war started. However the Soviet atomic bomb test of 1949 forced a speedy review of this naive thinking and UK defence planners urgently started to investigate the need to build an advanced modern integrated air defence network to replace the obsolete and inadequate WWII systems.
The Cherry Report called for a reorganisation of existing radars and development of new systems along with new control centres to better coordinate fighters and anti-aircraft guns. This was a stop-gap measure. In the longer term there would be a requirement for new much improved long range radars in place of the obsolete Chain Home systems from WW2 with construction of command and control sites able to survive nuclear attack in conjunction with high performance fighters and anti-aircraft missiles with anti aircraft guns as a last resort.
The missile aspect was the latest technology involved and of which the UK had little knowledge or experience. In order to urgently investigate and gain experience with these systems a Stage Plan was developed.
Stage 1 called for missiles based on a Liquid Oxygen and Petrol Guided Anti-aircraft Projectile ( LOPGAP ) missile with a range of only 20 miles with the ability to target subsonic or low-supersonic attacking aircraft at medium or high altitudes. I seem to recall that petrol was quickly deemed to be unsuitable and quickly substituted with ethyl alcohol.
The longer range Red Heathen project then became Stage 2 aiming to replace the Stage 1 design in the 1960s
The Royal Aircraft Establishment suggested the use of a ramjet for power because of the greater fuel economy. Bristol had little experience with this engine design so they began a long series of development tests. A ramjet only operates effectively at high speeds over Mach 1 so Bristol built a series of test airframes to flight-test the engines. The first, JTV-1, resembled a flying torpedo with the ramjets fitted to the end of the cruciform rear fins. Early problems were corrected and the JTV 1 became the first British ramjet missile to fly at supersonic speed and also proved various possible boost configurations.
Once the JTV testing was underway Bristol studied a series of airframe designs.
1/ The first was a long tube with an intake at the front, and four delta-shaped fins near the front of the fuselage. However this left little internal room for fuel or guidance as the tube ran down the centre of the entire fuselage.
2/ A second design was similar but used mid mounted fins of reverse delta shape with small intakes at their roots. The performance of these intakes was not well understood and development along these lines was thought unwise.
3/ The final design was essentially a small aircraft, with mid-set trapezoidal wings and four small swept wing fins at the rear. In this version, two engines were mounted on the wing tips, similar to the mounting used on the JTV series and therefore better understood.
One unique feature of the new design was the aerodynamic control system known as twist and steer. In the initial designs with a single very large solid fuel booster launched the missile from its launcher and propelled it to speeds where the ramjets could take over.
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Flight testing
In 1952 the design was accepted by the Combined United Kingdom/Australia Committee for Trials. A prototype of the new layout was built and flown in Wales as the 1⁄4-scale XTV-1, powered by three 5-inch boosters strapped together. This revealed issues with the length of the boosters.
The booster was redesigned as four smaller rockets around the missile fuselage. This layout was tested on the 1⁄3 scale XTV-2. Later the full sized but unpowered XTV-3 that tested the new boosters. Finally the full-sized and powered XTV-4. The final modification, first tested on the XTV-3, was to replace the four rear fins with two larger ones, which allowed the four booster motors to be mounted on a common ring ensuring they separated in different directions. This resulted in the standard XTV-5.
The engine requirements were finalized with the installation of the Bristol Thor designed in conjunction with Boeing. Testing of the prototype production versions, known as XRD (eXperimental Red Duster), moved to the Woomera range in South Australia in mid-1953. These proved very disappointing due to ramjet problems which were traced to the ignition system. This was replaced with an igniter design provided by the National Gas Turbine Establishment. Firings against GAF Jindivik target drones started in 1956,and eventually 500 tests of all of the designs were completed before it entered service.
Guidance was semi-automatic with the targets initially identified by existing early warning radar sites and then passed to the Bloodhound sites for local tracking and interception. 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' so degrading low-level capability.
By the time Bloodhound was ready for service the solid fuelled Red Shoes, now known as the English Electric Thunderbird was proving successful and the British Army cancelled its orders for the Bloodhound in favour of the Thunderbird.
The Bloodhound Mk 1 entered British service in 1958, and was selected for the Royal Australian Air Force in November of that year. Deployment of the Bloodhound Mk I began in 1958 to provide protection for the RAF's V Bomber bases.
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Bloodhound Mk II
By 1955 it appeared that the Stage 2 missile originally known as Green Sparkler, now as Blue Envoy, would not be ready before the Thunderbird and Bloodhound became obsolete. However the much improved continuous wave radar systems being developed for the same project were progressing well. In order to address the performance gap due to the delays, interim Stages were added to the Stage plan. "Stage 1½" combined a slightly upgraded Thunderbird with radar technology from Blue Envoy, while "Stage 1¾" would do the same to Bloodhound.
In 1957 the entire Stage concept was abandoned as part of the 1957 Defence White Paper. The Paper stated that the Soviets were increasingly likely to change their strategic attack to ballistic missiles and the possibility of an air attack solely by bombers would diminish as an attack of this nature would simply signal that missiles were also on their way. In that case, defending the V bombers against air attack achieved nothing and the only way they could survive would be to launch to holding areas at the first hint of an imminent attack. In this case, there was no point trying to defend the bomber bases and Blue Envoy was not needed.
Its cancellation took Bristol by surprise and their missile division Bristol Dynamics had no other projects to fall back on. Bristol engineers and their colleagues at Ferranti decided on a new scheme to adapt the Blue Envoy ramjets and radars to a lengthened Bloodhound,. They submitted this for study and the idea was accepted which resulted in the production of the Bloodhound Mk II.
The Mk II had a more powerful Thor engine based on modifications investigated in Blue Envoy. The increased power of this engine allowed the weights to increased and to take advantage of this the fuselage was stretched to allow more fuel storage. These changes significantly extended range to 50 miles pushing the practical engagement distance from 20 miles to more than 30 miles.
The Mk II was guided by either the Ferranti Type 86 Firelight radar for mobile use or the larger fixed 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 Bloodhound missile body onto the same antenna framework. 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 feet which was impressive for the time
The use of a continuous wave radar presented a problem for the semi-automatic guidance system. These systems rely on the Doppler effect to detect moving targets comparing returned signals to the radar signal being broadcast and looking for any shift in frequency. 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 since 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.
Many of the calculations of lead, frequency shifting and pointing angles for the radars were handled by the custom built Ferranti Argus computer.
The Mk II started tests in 1963 and entered RAF service in 1964. An impressive achievement. 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 accommodate the Mk II.
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The Lincolnshire Bloodhounds.
Bloodhound Mk I
With the development of the Bloodhound Mk1 force throughout eastern England North Coates became the HQ of 148 Wing from May 1960 and through it tactical control centre commanded a total of three missile squadrons, 141 at Dunholme Lodge, 222 at Woodhall Spa and 264 at North Coates.
The importance of the Bloodhound to the RAF was evident from the number of VIP visitors to the airfield including delegations from Canada, Switzerland, Norway Sweden, Turkey and India.
Many Parliamentary visits also took place including the Rt Hon Duncan Sandys in June 1959. It was in that year the main runway, which was 4250 ft long, was resurfaced. The hangar aprons were not resurfaced till 1964 however. From the mid 60s the runway was closed to allow the extension of the fencing round the missile site to allow for a storage area for the loading and unloading of missiles. From that time VIPs usually arrived by helicopter.
The Bloodhound introduction meant a major expenditure on operational facilities but the station was still effectively a hutted camp. Despite significant spending on airmen's facilities new buildings were required and in 1962 the first of 3 new accommodation blocks was built and occupied by personnel of the Technical Wing. In June an airmen's mess was opened and in November the Campbell Club was opened by Mrs Clayton, wife of the station OC. The officers were still awaiting completion of the new Officer's Mess whilst living in facilities more Spartan as the previous wooden building had burnt down.
264 Sqn disbanded on the 30 November 1962 and by the end of the year the Tactical Control Centre had been closed and the Type 82 radar withdrawn from the UK air defence system. During the severe winter of 1962/63 the Bloodhound Mk I equipment was withdrawn and preparations made for the replacement. HQ 148 Wing was disbanded in the 1 February 1963 but the same day 148 SAM Servicing Wing was formed to sustain the remaining elements of the Bloodhound Mk I force until it was also disbanded on the 30 April 1964.
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Bloodhound Mk II – The Great Leap Forward
The development of the Bloodhound Mk 11 continued apace and by 1960 it was ready for service trials.. During October 1960 17 Joint Service trails Unit was formed at North Coates to carry out operational trials of the new missile and see it brought into service. 15 JSTU was formed at Woomera Australia to conduct the live firing trials. To allow thee development of facilities the Mk I was taken out of service on the 1 October 1963.
25 Sqn formed at North Coates began to work up on the Bloodhound Mk II. Also established at North Coates during October 1963 was the SAM Missile Operational Training School - SAMOTS. 25 Sqn was later expanded to include that of the SAMOTS and in August 1964 the two units amalgamated. With the development of the Mk II complete 17 JTSU disbanded in December 1966
The Bloodhound Mk I was mobile and was often displayed at Farnbrough and the Paris Air Show and deployed from Binbrook in Beverley and Argosy aircraft.
In 1969 as part of Exercise Illusionary to test mobility 25 Sqn deployed by road and air to Woodhall Spa in March. The airlift was consisted of 7 Hercules loads flown between Binbrook and Coningsby. This provided valuable experience for 25 Sqn prior to their urgent deployment to Germany to meet NATO commitments. The move started in April 1970 when personnel moved to Laarbruch by road and air and was completed on the 31 May. C Flight was declared fully operational at Laarbruch on the 15 June.
At North Coates the Operations Flight the training element of 25 Sqn moved to West Raynham in July and the Squadron HQ was formed at Bruggen in August 1970. Equipment continued to be transferred to Germany until the end of the year and the unit was finally declared operational on the 31 January 1970. With their departure North Coates was reduced to a care and maintenance basis with many buildings redundant and at least one hangar was used for storage.
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However in March 1976 North Coates was opened again with the formation of B Flight 85 Sqn which was a former Canberra unit re-equipped with the Bloodhound Mk II and formed with its HQ at West Raynham. North Coates had fully maintenance facilities. Later in 1987 Hangar 2 was reclad and refurbished to provide accommodation for missile servicing equipment and the old launch control post and generator buildings converted to office and workshop accommodation. B Flight received the advanced Type 87 radar and missiles and ancillary equipment returned from Cyprus and Singapore. On its reopening North Coates was parented by Binbrook till 1988 when the roles were reversed months before Binbrook was shut down.
With the introduction of the Rapier SAM system in Germany 25 Sqn returned to Wyton with North Coates remaining the home of B Flight 85 Squadron. A large scale clear up of the old and derelict buildings began in 1982/83with refurbishment of he airman's mess to convert it into a training school for technicians and as a result the Bloodhound Missile System Maintenance School moved to North Coates from Newton and training commenced in April 1987.
With the policy of radar standardisation the Type 87 radar was gradually replaced by the smaller and more mobile Type 86 which gave better detection against low flying targets. The Type 86 was mounted on a helideck fitted to the base of the plinth of the old Type 87. At around this time the missile sections were provided with much improved accommodation
The last big open day at North Coates was held on the 25 June 1988 with fly ins by Vulcans, Lightnings and Tornados
The end came on 28 February 1990 when the Ministry of Defence announced the contraction of the Bloodhound force and the site at North Coates would be closed. From April to May 1990 the operational equipment was moved to West Rayham and the wind up of the station began. The married quarters were vacated and the equipment withdrawn by the end of November and RAF Station North Coates was officially closed and handed over to the Defence Land Agents for disposal on the 18 December 1990
Compiled by David Fell. Top photo IWM. Others from my archive
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