Late great engineers: Hilda Lyon

Nick Smith explores the life of one of the most important women engineers of the 20^th century, Hilda Lyon, whose name lives on in her eponymous ‘Lyon Shape’ streamline design used in submarines and airships.

On 26^th June 2019 the small Yorkshire town of Market Weighton played host to a blue plaque unveiling commemorating the life of Hilda Lyon, a shopkeeper’s daughter who was to become one of the most influential women engineers of the 20^th century. The unusually long citation narrative that follows her name, post-nominal letters and general description of her as ‘aeronautical engineer,’ credits her with helping to design the R101 airship, inventing the ‘Lyon Shape’ and being the first female recipient of the Royal Aeronautical Society’s R38 Memorial Prize. Beneath this list of accolades, the blue plaque (located at her father’s shop in the town’s High Street) reads: ‘Her work is still used for stability software and submarine design.’ For Lyon’s relatives – many had crossed the Atlantic for the ceremony – this recognition of the British engineer, described by Flying magazine in 1934 as “the classic authority on the subject of stresses in transverse frames,” was both overdue and appreciated.

Hilda Margaret Lyon was born in Market Weighton in 1896 in the final decade of Queen Victoria’s reign. It was the year of the introduction of the x-ray machine, the first ever scientific paper on the sensitivity of the global climate to atmospheric carbon dioxide, Henry Ford’s first car ‘the Quadricycle’ and the launch of the legendary French motion picture company Pathé. As the 19^th century drew to a close, the Anglo-German naval arms race spawned by the creation of the German Reich after the Franco-Prussian War had already planted the seeds of the First World War. But for Lyon, who came from a family of shopkeepers and farmers in the relative tranquillity of a remote northern town, global events played little part in her early years. In fact, she spent most of the Great War at Newnham College, University of Cambridge, from which she obtained a BA in mathematics in 1918, styled ‘title of degree’ because Cambridge wasn’t to award full degrees to women until 1948.

After graduating, Lyon took an Air Ministry course in aeroplane stress-analysis that in turn led to her taking a job as a technical assistant. Realising this position offered neither further promotion or responsibility ‘for a woman mathematician’ she resigned from the ministry and took a six-week sabbatical in Switzerland. It’s not easy to establish exactly why she went on this trip with her sister, but it provides insight into her propensity for world travel that was to be a feature of her distinguished career in both academia and industry. It is, however, a matter of record that on her return to the UK later in 1918 she worked for a number of British manufacturers, including a stint at the Siddeley-Deasy Motor Company as a technical assistant, before moving on to aircraft builder Parnall & Co in 1920 (where she probably worked on Puffin, Possum, Pixie and Perch aircraft). During1922, Lyon was admitted as an Associate Fellow of the Royal Aeronautical Society, and by the mid-1920s she found herself on the technical staff at the Royal Airship Works in Cardington as part of a team developing the R101 minimum-drag hull, rigid airship.

After the end of the First World War, the UK government had recognised the potential for airships as a method of modernising communications with Britain’s overseas colonies and for transporting troops. With a length of 731ft, the R101 was the largest flying machine ever built and was to remain so until the introduction of the Hindenburg seven years later. Prior to its first flight, Lyon wrote to her brother: “When are you coming to see the R101? Hope that it’s a north wind when I get my first flight so that I can persuade them to fly over Market Weighton though it looks like rubbing it in too much to the Howden people.” The ‘Howden people’ Lyon refers to was the Yorkshire-based commercial manufacturer of the R100 airship that was pitched in direct competition to the R101. According to Lyon’s relative Rosi Lambkin, ‘the Air Ministry were desperate for a flight to India to be undertaken, despite the lack of full endurance and speed trials.’ As with the more famous Hindenburg, the R101 met with disaster, crashing in northern France during its maiden overseas Karachi-bound voyage on 5th October 1930, killing 48 of the 54 people on board. The government responded by shelving the entire airship programme and had the remaining R100 broken up.

Although Lyon had flown on the R101 maiden test flight – writing to a cousin to say how she’d ‘enjoyed it immensely’– she was not on board that fateful flight to India, having left her job at Cardington shortly before to take up studies across the Atlantic at the Massachusetts Institute of Technology. At MIT she worked with experimental wind tunnels and engineering laboratories, where her research identified the optimum shape for an airship, which became known as the ‘Lyon Shape’ (a term that is still current in the US) and was also incorporated into the 1953-commissioned American submarine USS Albacore that had a streamlined hull specifically designed for underwater running, as well as subsequent American submarines and designs by other overseas manufacturers. Lyon also took the opportunity at MIT to submit her master’s thesis – ‘The Effect of Turbulence on the Drag of Airship Models’ – that she’d completed in her spare time while still at the Air Ministry.

On completion of her stay at MIT, Lyon departed America on the second of her traveling scholarships for Göttingen in Germany, where she conducted research at the Kaiser Wilhelm Gesellschaft für Strömungsforschung (now the Max Planck Institute for Dynamics and Self-Organization) under the German scientist and pioneer in the field of aeronautical engineering Ludwig Prandtl. Based on its classic tear-drop ‘Albacore hull’ profile, it remains possible that Lyon’s work at Göttingen may have influenced the design of the German midget speed attack Delphin-Class (‘dolphin’) submarine, of which only three prototypes were ever built.

“I have just had my first flight and enjoyed it immensely… it was quite a short joy ride.” Hilda Lyon.

Lyon’s time at Göttingen ended prematurely when her mother became ill, leaving her with few options other than to return to Yorkshire in order to care for her. Perhaps unusually for a female scientist at the time, Lyon was able to maintain contact with her field, while keeping up with her research into aerostatic flutter and elastic blades by using university libraries in Hull and Leeds and by visiting the National Physical Laboratory and the Royal Aircraft Establishment (RAE). What might under normal circumstances have been a career-ending hiatus was avoided due to the foresight of her former supervisors at the Royal Aircraft Establishment who, realising the significance of her expertise, encouraged Lyon to continue her work from home. In the two years prior to her mother’s death in 1934, Lyon was able to publish two scientific papers on streamlining and boundary layer effects, followed by a further two papers in 1935, after which the RAE created the post of Principal Scientific Officer in its aerodynamics department at Farnborough to open the door for her full-time return to work in 1937. She would also serve on the Aeronautical Research Council and sat on the RAE Education Committee where she showed a keen interest in apprentice training.

As fellow RAE engineer Frances Bradfield noted in her obituary of Lyon, “a four-year break would have ended most women’s work.” Instead, Lyon published scientific research papers frequently for the rest of her career (as well as posthumously), while her war work included involvement in stability analysis for the Hawker Hurricane single-seat fighter aircraft that was to play a pivotal part in the Battle of Britain in 1940, as well as seeing combat in all major theatres of the Second World War. Her 1942 paper – “A theoretical analysis of longitudinal dynamic stability in gliding flight” – is widely held as a classic and is to this day cited in the world of streamlining and boundary layers.

Lyon died in Surrey in 1946 at the age of 50 and is buried in Market Weighton. While little is known of how she died (other than it appears to have followed a medical operation), what is clear is how deeply her loss to the aeronautical engineering community was felt. Director of the RAE, W G Perrin wrote of Lyon after her death: “She won a real place in our affections., and by her painstaking and steady effort she claimed the respect of everyone who was privileged to work with her. She will be missed by all her friends both at the RAE and in industry and her death is a loss that will be felt throughout the scientific world.”