David J. Farrar
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David J. Farrar (born 1921) is an English engineer who led the Bristol team which developed the Bristol Bloodhound surface-to-air missile, which defended Britain's nuclear deterrent for many years and were widely sold abroad.
Early life and education 
Born in London, England in 1921, Farrar was the elder son of Donald Frederic Farrar (1897–1982), a former Royal Flying Corps supply pilot, and Mabel Margaret Farrar, née Hadgraft (1896–1985), and brother of RAF airman and poet James Farrar.
He was educated at Sutton Grammar School for Boys, Surrey, and won three scholarships to Cambridge University, going up in 1939 to Gonville and Caius College. In his second year Farrar (at the age of nineteen) passed the Mechanical Sciences tripos First Class with distinctions and a share in University prizes for aerodynamics and structures.
It being the eve of World War II, he expected to go into the Royal Air Force, having been an active member of the University Air Squadron, but was assigned to the aircraft industry in the Bristol Aeroplane Company, where he specialised initially in structural design. By the age of 25 he had devised new approaches to the design of compression structures  and was in charge of the structural design of Britain's largest landplane, the Bristol Brabazon aircraft.
In 1949, Farrar made in-flight observations of wing buckling in a Bristol Freighter, which then did full power engine cut tests. On the next flight with the chief aerodynamicist and the head of flight test on board, full power engine cut caused the fin and rudder to break and all aboard were lost. The head of flight test was the designated head of the new Guided Weapons department, to which Farrar then succeeded. Contracts having already been let for army and navy anti aircraft systems, Bristol and Ferranti were teamed to study a longer range system for the Royal Air Force. The key to longer range was ramjet propulsion, which required extensive flight development. Despite this, the resulting Bloodhound 1 missile entered service before the other two.
On the formation of the British Aircraft Corporation Bristol had joined as a junior partner, with all guided weapon work assigned to English Electric, whose guided weapon team had commenced the development of a weapon with second generation continuous-wave radar (CW) guidance. The Bristol GW team was vulnerable, and two attempts to eliminate it were made. A Bloodhound I missile was rapidly modified to CW guidance and intercepted and destroyed the target aircraft. The other contractors had not reached this stage, so the Bristol Bloodhound II was developed for the Royal Air Force, Sweden and Switzerland. Its advanced features gave it a very long service life.
Farrar was appointed Technical Director of the combined GW Division, but within a short time all three Bristol directors who had opposed elimination of their team had been forced out.
He then became Engineering Director, Concorde, at Bristol. The Government was concerned about cost escalation and programme slip on the project and part of his brief was to correct these. With the help of a new programme manager and econometrics engineer, within a year (before the first prototype was built) he correctly established the causes as repeated redesign for an unrealistically low takeoff weight, and high aircraft cost. The latter had not been previously predicted and made airline orders unlikely. However, the French direction rejected design for a more realistic weight, so programme slip and cost escalation continued.
When international collaboration commenced on the Space Shuttle design, he became the Director responsible for three British teams designing the payload bay doors, vertical stabilizer and instrumentation in Rockwell's winning bid for development. In 1973 he left the aircraft industry to became Engineering Director at Molins Ltd., developing a range of advanced machinery which provided the basis for their launch as a public company.
In 1979, Farrar became Director of the Centre of Engineering Design at Cranfield University, retiring in 1986. He became Vice President until 2007 of the University of the Third Age at Manningham, Australia and lectures there on the History of Technology.
Awards and honors 
He received the OBE for his work on Bloodhound I, and the teams which he led received four Queens Awards for exports and technology. He was the first Chairman of the Society of British Aircraft Constructors Guided Weapons Committee, a member of Royal Aeronautical Society council, served on many professional committees, and in retirement lectured for the Institution of Engineering Designers from whom he received an Honorary Fellowship.
Personal life 
He married in 1950 Bridget Kiely. Their two children, Claire and Kevin, died from cystic fibrosis. Ten years after Bridget's death he married Fay McEnaney and emigrated to Australia, where they have two sons, a daughter and grandson.
- Russell, Sir Archibald. (1992) A Span of Wings. Airlife.
- Adams, A.R. (1976). Good Company. The British Aircraft Corporation, Stevenage.
- Nick Gardner. (2007). Mistakes: How they happened, and how they might be avoided.
- Richard Hall (1976). The Making of Molins. Molins Ltd.