English Electric Thunderbird

The English Electric Thunderbird was a British surface-to-air missile produced for the British Army. The Thunderbird was primarily intended to attack higher altitude targets at ranges of up to thirty miles or so. AA guns were still used for lower altitude threats. They were the Army's only heavy surface to air guided weapon and were not replaced (by another heavy guided SAM) when they left service.

The Stage Plan
The Thunderbird originated in a proposal to English Electric in 1949 to develop a missile to provide ground based air defence to the British Army in the field. As such, it was intended to replace the 3.7-inch heavy anti-aircraft gun that fulfilled this role during World War II. Like the 3.7, the new missile would be operated by the Royal Artillery. English Electric created a Guided Weapons Division to work on the project.

While the project was starting, the Ministry of Supply (MoS) began work on what would become known as the "Stage Plan", which envisioned a multi-stage program to provide an integrated air-defence network including new radars, interceptor aircraft, and missiles. As the missiles were the least understood technology, the MoS decided to implement their deployment in two stages. "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. The Stage 1 missile would be later replaced with a much higher-performance and longer-range "Stage 2" system in the 1960s, based on the "Green Sparkler" missile. The Stage 2 missile was to have greatly increased range, speed and altitude capabilities.

Two entries were accepted for the original Stage 1 proposal, English Electric's existing project under the name "Red Shoes", and Bristol's "Red Duster". Bristol's efforts were fairly similar to EE's in most ways, although it was somewhat less mobile while offering somewhat better range. As both designs were generally similar in performance, a single set of radars was developed that could be used with either design. This consisted of a Ferranti developed search radar and the target illuminating radar was the RRDE's "Yellow River" fire control radar built by British Thomson-Houston.

Development


EE's design quickly developed into a fairly simple cylindrical fuselage with an ogive nose cone, four cropped-delta wings just behind the middle point of the fuselage, and four smaller control surfaces at the rear, in-line with the mid-mounted wings. The fuselage had a slight boat-tail narrowing at the extreme rear under the control surfaces. The sustainer was to be a liquid fuel rocket developed for the missile, and was launched by four large "Gosling" solid fuel rocket boosters lying between the control surfaces and wings. The boosters featured a single oversized fin of their own, and are particularly easy to spot due to a small flat surface at the end of every fin. This surface provided an outward drag component that help pull the booster away from the main body when released, helped by the booster's asymmetrical nose cone. Guidance was via semi-active radar homing, the Ferranti Type 83 "Yellow River" pulsed radar serving both as an acquisition and illumination system. The same radar was used with the competing Red Duster.

The test programme used development vehicles D1 to D4. The D1 and D2 established some of the basic configuration issues, whilst the D3 and D4 were used to test the aerodynamics of the design. The Army rejected the idea of using a liquid fuel rocket because of the difficulty in handling the highly reactive fuel in the field, so a solid rocket sustainer had to be chosen instead. Several different models of sustainer were tried, most of them known as the "Luton Test Vehicle", or LTV.

While testing of the Red Shoes was underway, the "competition" in the form of Red Duster was also entering testing. Red Duster demonstrated several serious problems, and the Army ended any interest in it. In the end the Red Duster problems were sorted out fairly quickly, and it entered service slightly before Red Shoes, as the Bristol Bloodhound, Mk. I.

The production Red Shoes missile was officially named Thunderbird. It entered service in 1959 and equipped 36 and 37 Heavy Air Defence Regiments, Royal Artillery. It was the first British designed and produced missile to go into service with the British Army.

Further development
While development of the Stage 1 missiles was still ongoing, work on the Stage 2 systems was proving to be too far in advance of the state of the art to realistically enter service while the Red Duster and Red Shoes were still useful. In the meantime, advances in radar technology were proceeding rapidly, so it was decided to produce interim designs using new continuous wave radars which would dramatically improve the performance of the existing missiles.

In the case of the Thunderbird, the "Stage 1½" design utilized the new Type 86 "Indigo Corkscrew" radar. As this was developed it changed names several times, becoming "Green Flax", and after some paperwork with that name on it was lost and assumed compromised, "Yellow Temple". In service it was known as Radar, AD, No 10 (fire control). The new radar greatly improved performance against low-level targets, as well as providing considerably better performance against electronic countermeasures.

To support Thunderbird operations in the field the regiments were equipped with the new Radar, AD, No 11 (tactical control, usually called 'big ears') and Radar, AD, No 12 (height finder, usually called 'noddy') radar, giving them a longer range surveillance system. These radars were also known to Marconi as the S303 and S404, or to the RAF as Type 88 and Type 89. After leaving Army service in 1977 they were turned over to the RAF who used them for tactical control.

Several changes to the basic missile were undertaken as well. Although the size remained the same, the new version featured much larger boosters, mid-mounted wings with sweep on the front and back, and a new nose cone with a much higher fineness ratio. The boosters lost their asymmetrical nose cones, but the surfaces on the end of their fins grew much larger. Overall the missile still looked much like the Mk. I version, as opposed to the Bloodhound which became much larger as it was upgraded.

The improved missile was known in service as Thunderbird 2. They entered service in 1966 and were removed in 1977.

Former Operators

 * : British Army
 * 🇫🇮: Finnish Army - planned purchase of either was Thunderbird or Bloodhound was eventually cancelled, but only after deactivated training missiles had been delivered in the late 1960s. These were used in the training role until 1979.
 * 🇸🇦: Royal Saudi Air Force - 37 second-hand Thunderbird I missiles purchased in 1967
 * Negotiations were also held with Libya and Zambia.

Survivors
Thunderbird remains a popular museum item in the UK. One of the missiles is now displayed outside the Midland Air Museum, Warwickshire, England. Another example on a launcher is displayed in The Royal Artillery Museum, Woolwich, England.

Two of the Finish missiles survive, one missile is located in Artillery Museum, Hämeenlinna, another in the Anti-aircraft Museum, Tuusula.

Specifications

 * Length : 6.35 m
 * Body Diameter : 0.527 m
 * Fin Span : 1.63 m
 * Warheads : Continuous HE rod
 * Range : 75 km