BAC Bloodhound
surface-to-air missile
The Bloodhound missile system provided the RAF with an effective ground-to-air interception capability for 32 years, until its retirement in 1991.
Originally designed to deal with high altitude intruders, this system was also capable of tackling low flying targets. The Bloodhound's ability to home in on radar-jamming signal from the intruder, as well as its large proximity-fused high-explosive warhead, made it a lethal element in the defence of UK airspace.
The missile is displayed here in the markings of No 85 Squadron, who operated the Bloodhound from late 1975.
Clustered around the main body of the missile can be seen the four solid-rocket boosters - each with a large fin at its base - and two large 'Thor' rakjets, which powered the missile to its target at twice the speed of sound.
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.
Designed to provide a last line of defence for the V bomber bases to destroy any Soviet bombers that got past the defending Lightning interceptor force operating over the North Sea, the Bloodhound Mk. I entered service in December 1958, and began to be replaced by the much more capable Mk. II starting in 1964. The last Mk. II missile squadron stood down in July 1991, although Swiss examples remained operational until 1999.
The Bloodhound Mk. II was a relatively advanced missile for its era, roughly comparable to the US's Nike Hercules in terms of range and performance, but using an advanced continuous-wave semi-active radar homing system, offering excellent performance against electronic countermeasures, as well as a digital computer for fire control that was also used for readiness checks and various calculations. It was a relatively large missile, which limited it to stationary defensive roles similar to the Hercules or the Soviets' S-25 Berkut, although the Swiss operated theirs in a semi-mobile form.
Bloodhound shares much in common with the English Electric Thunderbird, including some of the radar systems and guidance features. Thunderbird was smaller and much more mobile, seeing service with the British Army and several other forces. The two served in tandem for some time, until the shorter-range role of the Thunderbird was replaced by the much smaller and fast-acting BAC Rapier starting in 1971. Bloodhound's longer range kept it in service until the threat of bomber attack by the Soviet Union disappeared with their dissolution in 1991.
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 midpoint, providing pitch and roll control by pivoting in unison or independently with additional steering provided by differential fuel feed to each of the ram jets. Two smaller rectangular fixed surfaces were mounted in-line with the main wings, almost at the rear of the missile.
The boost engines are held together as a single assembly by a metal ring at the rear of the missile. Each motor has a small hook on the ring as well as similar one at the front holding it to the missile body. After firing, when the thrust of the rockets falls below the thrust of the now-lit ramjets, the boosters slide rearward until the front hook disengages from the missile body. The boosters are then free to rotate around their attachment to the metal ring, and are designed to rotate outward, away from the fuselage. In action, they fold open like the petals on a flower, greatly increasing drag and pulling the entire four-booster assembly away from the missile body.
Small inlets on the roots of the stub wings holding the engines allow air into the missile body for two tasks. Two ram air turbines driving turbopumps generate hydraulic power for the wing control system, and a fuel pump that feeds the engines. Smaller inlet tubes provide ram air to pressurize the fuel tanks. Kerosene fuel is held in two large rubber bag tanks in bays either side of the wing bay where the wings are attached. Electrical power was provided by a molten salt battery ignited at launch.
Although in tests the Bloodhound had executed direct hits on target bombers flying at 50,000 ft, Mark II production models, in common with many air-to-air and surface-to-air missiles of that period and after, had a proximity fuzed continuous rod warhead (known as the K11A1) designed to destroy attacking aircraft without requiring a direct hit.