60: Letitia Chitty

Engineer of the Week No.60: Letitia Chitty M.A., C.Eng,. F.R.Ae.S., M.I.C.E. (15 July 1897-29 September 1982)
On her 142nd birthday we remember Letitia Chitty, aeronautical and civil engineer.
Letitia Chitty was a talented mathematician who translated that into engineering, analysing the stresses of airframes, ships and civil engineering structures and became the first female fellow of the Royal Aeronautical Society. Born into a well-off family in London, her father was a barrister, Letitia’s godmother was Violet Jex-Blake, niece of Sophia Jex-blake, the first female medical graduate in the UK. Her mother’s male relatives were part of the public-school heirarchy and it is clear that Letitia had support for her educational aspirations.She attended Kensington High school and then started to study maths at Newnham College, Cambridge. However, having done Part I of the Mathematics Tripos, she left to go to the Admiralty Air Department in 1918, where she worked with a group of other young women and men under Alfred Pippard. She recalled of this period: “There were no programmes, no calculating machines … we relied upon our slide rules and arithmetic in the margins … Lives were at stake and we couldn’t afford to let anything go through wrong.”

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The Tarrant Tabor – or when even the best engineer cannot save a bad idea. W.G. Tarrant, previously a timber merchant,designed a massive bomber at the end of WW1. The original biplane design had to be altered to triplane to accommodate more engines and theAdmiralty Air Department was asked to check its structural strength. Leitia was given this task. In her own words (from Bill Gunston's book "Giants Of The Sky")"Mr. Tarrant was an inspired timber merchant who dreamed of a super-Camel. It hadn't a chance. It was too big, too heavy - that wasn't its fault, but Grade A spruce had by now run out and and it had to be built of American white wood (tulip). In my language 3,500 instead of 5,500 lb/sq in.". Tragically, her mathematical analysis was not heeded and the plane crashed nose down during its first take off, from the Royal Aircraft Establishment at Farnborough on 26 May 1919,killing both pilots and seriously injuring the other 6 people on board.
After the war Letitia returned to Cambridge and graduated from Newnham College with first class honours in the Mechanical Sciences Tripos, 1921, the first woman to do so. Her next job was for the Air Ministry’s Airship Stressing Panel which was looking into the causes of the crash of the R38 airship, followed by more analytical work for the Bristol Aircraft Company and research into the theory of fluid flow and framed structures for ProfessorRV Southwell at Oxford. 1934 was a significant year for Letitia: she won the R38 Memorial prize for her paper ‘Tapered Frameworks Representative of the Airship Hull’, became the first woman Fellow of the Royal Aeronautical Society and became a Research Assistant at Imperial College. This was when she made the big change in her career from aeronauticl to civil engineering and started her specialism in the structural stresses of arches and dams. In 1943 she was promoted to lecturer. Her research into the plastic collapse of cylindrical shells led to the Admiralty asking her to investigate submarine hull stresses in underwater explosions. Other WW2 work included stress analyses of the extensible cables and pulley blocks for barrage balloons, for the Director of Scientific Research of the Admiralty and the Ministry of Supply.
In 1951 the civil engineering firm of George Binnie was contracted the Iraq governmentto build the Dokan dam in a tributary of the Tigris river and asked Professor Pippard and Letitia Chitty to look at the stresses involved. They developed a stress analysis technique using relaxation methods and a rubber model to verify the design form, in an important on the conventional trial load method then in general use. Their work resulted in a single curvature arch dam of single curvature to suit the profile of the gorge. The dam is still in use. In 1958 Letitia was the first woman to be appointed to a technical Committee of the Institute of Civil Engineers and published 8 learned papers on her aeronautical and civil engineering researches. She retired from Imperial College in 1962, but continued her involvement there. Other recognitions of her talent came in 1969 when she was awarded the Telford Gold Medal (the highest award of the Institution of Civil Engineers) and in 1971 when she was made a fellow of Imperial College.
Letitia never married and generally lived with her mother or sister. She spoke many languages, travelled widely and was a talented artist and published a book, “Abroad. An alphabet of flowers”, in 1948, with her own drawings and notes about her holidays. Although shy and regarded by some as ‘eccentric’, she was warmly remembered for her kindliness and enthusiasm.Imperial College and Newnham College, Cambridge each have awards in her name.

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