Alan Blumlein

Alan Dower Blumlein was born on 29 June 1903 in Hampstead, London. His father, Semmy Blumlein, was a German-born naturalised British subject. Semmy was the son of Joseph Blumlein, a German of Jewish descent, and Philippine Hellmann, a French woman of German descent.[Note 1] Alan's mother, Jessie Dower, was Scottish, daughter of William Dower (born 1837) who went to South Africa for the London Missionary Society. Alan was christened as a Presbyterian; he later married in a Church of England parish church.[4]

Alan Blumlein's future career seemed to have been determined by the age of seven, when he presented his father with an invoice for repairing the doorbell, signed "Alan Blumlein, Electrical Engineer" (with "paid" scrawled in pencil). His sister claimed that he could not read proficiently until he was 12. He replied "no, but I knew a lot of quadratic equations!"

After leaving Highgate School in 1921, he studied at City and Guilds College (part of Imperial College). He won a Governors' scholarship and joined the second year of the course. He graduated with a First-Class Honours BSc two years later.

In mid-1930, Blumlein met Doreen Lane, a preparatory school teacher five years his junior. After two-and-a-half years of courtship the two were married in 1933. Lane was warned by acquaintances before the wedding that, "There was a joke amongst some of his friends, they used to call it 'Blumlein-itis' or 'First Class Mind'. It seems that he didn't want to know anyone who didn't have a first class mind." Recording engineer Joseph B. Kaye, known as J. B. Kaye, who was Blumlein's closest friend and best man at the wedding, thought the couple were well matched.[5][6]

Halifax II V9977, which crashed on 7 June 1942, pictured at RAF Defford. Note the H2S radome under the belly.[3]

Blumlein was killed in the crash of an H2S-equipped Handley Page Halifax test aircraft while making a test flight for the Telecommunications Research Establishment (TRE) on 7 June 1942. During the flight from RAF Defford, whilst at an altitude of 500 ft (150 meters) the Halifax developed an engine fire which rapidly grew out of control.[9] The aircraft was seen to lose altitude, then rolled inverted and struck the ground.[9] The crash occurred near the village of Welsh Bicknor in Herefordshire.[10] Two of Blumlein's colleagues, Cecil Oswald Browne and Frank Blythen, also died in the crash.

The Halifax was carrying a highly-secret cavity magnetron as part of the H2S test system, and the immediate recovery of the device was essential. A team led by Bernard Lovell arrived at the crash scene the same night, and took the magnetron.[11]

"Then reports of a crash in south Wales began to come in and the rest of that night was just a nightmare. I was driven by the C-in-C of the aerodrome [Defford], a man called King,[12] and winding through these lanes near Ross-on-Wye searching for this wreckage, and then the field with the burnt-out Halifax, and of course it was wartime, there was no time for emotions, our first duties were to search for the precious highly-secret equipment, and collect the bits-and-pieces of it." – Bernard Lovell. [13]

Memorial window at Goodrich Castle commemorating Blumlein and the other engineers, scientists and servicemen involved in radar development

After the RAF investigative board completed its report on the Halifax crash on 1 July 1942, it was distributed to a restricted list of approved recipients, but not publicly divulged.[9] In the interests of wartime secrecy, the announcement of Blumlein's death was not made for another three years.[14] The investigative board, headed by AIB Chief Inspector Vernon Brown – who later also investigated the post-war Star Tiger and Star Ariel disappearances – and assisted by Rolls-Royce, who had made the Halifax's Merlin engines, found that the crash was caused by engine fire, attributed to the unscrewing of a tappet nut on the starboard outer engine, which had been improperly tightened by an RAF engine fitter while inspecting the engine three hours prior to the crash.[9]

During the flight the loosened nut caused increasingly excessive valve clearance eventually allowing collision of the valve head with the rising piston fracturing the valve stem, which then allowed the inlet valve to drop open, resulting in the ignition by the spark plug of the pressurised fuel/air mixture within the inlet manifold and, eventually, the pumping of the ignited fuel outboard of the rocker cover and along the outside of the engine, leading to an extensive fire in the engine nacelle.[9] Due to the fire originating in the induction system, where the supercharged fuel/air mixture was at higher pressure than atmospheric, the heart of the fire was much hotter burning and intense than would be the case in a simple fuel fire.

Constantly fuelled by the broken intake, the fire burned rapidly along the wing and fuselage, eventually causing the outboard section of the starboard wing to separate from the centre section at approximately 350 feet (100  meters) of altitude.[9] With the loss of a substantial part of the starboard wing, all control over level flight was lost, and the plane rolled inverted and struck the ground at approximately 150 mph (240  meters).[9]

The board found that the crew and passengers had not jumped immediately from the aircraft owing to several factors, including a loss of altitude while attempting to find an emergency field, the rapidly spreading fire, which blocked or impeded egress from the plane, and the fact that a sufficient number of parachutes were either not on board or were not being worn.[9] Almost immediately following the crash, Prime Minister Winston Churchill issued a directive requiring any test flights with civilians or scientific personnel to carry a sufficient number of parachutes for all individuals involved.[9]

After the RAF investigative board completed its report on the Halifax crash, it was ordered to be kept secret by Prime Minister Churchill, and the cause of the crash was not revealed publicly, even to the relatives of the deceased.[9] As a result, numerous unfounded rumours of German sabotage as the cause of the crash would circulate for many years afterwards.[9]

Alan Blumlein had two sons, Simon Blumlein and David Blumlein.

Outside his work Blumlein was a lover of music and he attempted to learn to play the piano, but gave it up. He enjoyed horse riding and occasionally went cub hunting with his father-in-law.[15]

He was interested in many forms of engineering, including aviation, motor engineering and railway engineering. He obtained a pilot's licence and flew Tiger Moth aircraft of the London Aerodrome Club at Stag Lane Aerodrome.[16] On one occasion, he persuaded a bus driver to allow him to drive the vehicle from Penzance to Land's End. On another he spent several hours assisting the operator of a railway signal box in his duties at Paddington Station.[17]

• Alan Blumlein Way is a road on the Tektronix campus in Beaverton, Oregon, in keeping with their policy of naming roads after those who made significant contributions to the knowledge and understanding in the field of electronics.
• There continues to be a meeting room named the Blumlein Room in the Institution of Engineering and Technology (IET) headquarters at Savoy Place, following a major refurbishment in 2015.[18]
• A Blue Plaque commemorating Blumlein was erected in 1977 by the Greater London Council at his former home in Ealing.[19]

Blue Plaque located in Ealing, West London

• On 1 April 2015 an IEEE Milestone Plaque was posthumously presented for the Invention of Stereo to Alan Dower Blumlein. A ceremony was held at Abbey Road Studios attended by many leading audio experts and recording engineers. The plaque is now located on the right hand side of the front door of Abbey Road Studios.

IEEE Milestone Plaque located on the right hand side of the front door at Abbey Road Studios

• In 2017, The Recording Academy posthumously awarded Alan Dower Blumlein with the 2017 Technical Grammy for the invention of Stereo and contributions of outstanding technical significance to the recording field.

Alan Dower Blumlein 2017 Technical Grammy

• Blumlein generator
• Blumlein transmission line, used to create high-voltage pulses with short rise and fall times.
• History of television

Citations

Bibliography

• Alexander, Robert Charles (1999). The Inventor of Stereo: The Life and Works of Alan Dower Blumlein. Focal Press. ISBN 0-240-51628-1.
• Burns, Russell W (2000). The Life and Times of A. D. Blumlein. IEE History of Technology series. IEE. p. 2. ISBN 0-85296-773-X.

Wikimedia Commons has media related to Alan Blumlein.

• The crashed Halifax aircraft V9977
• Blumlein page at AlanTuring.net
• Biography of Blumlein on IEEE Global History Network
• Binaural test records and manuscripts created by Alan Blumlein and his research team at EMI (British Library)
• Official Alan Dower Blumlein website