Gustav Lachmann

Gustav Victor Lachmann (3 February 1896 – 30 May 1966) was a German aeronautical engineer who spent most of his professional life working for the British aircraft company Handley Page. He was, with Frederick Handley Page, the co-inventor of the leading edge slot.

Lachmann was born in Dresden, Germany, in 1896, the younger son of Gustav Anton Lachmann, an Austrian industrialist, and his wife, Leopoldine Wilvonseder. He served as a lieutenant in the German Army cavalry during World War I before transferring to the flying corps in 1917 and training as a pilot. During flight training he stalled and crashed, breaking his jaw.

While hospitalised he turned his mind to the cause of his crash. He concluded that a series of small aerofoils contained within a normal wing section would possess improved low-speed characteristics. He rigged up a primitive flow-visualiation rig using a fan and cigarette smoke to confirm his ideas. He attempted to patent the principle, but the application was initially rejected by the German Patent Office on the basis that there was no proof that it would work. Lachman gave up the idea and enrolled at Darmstadt Technical University for a course in mechanical engineering and aerodynamics. He graduated in June 1921 and took a job with the Opel factory.

By chance he read an account of Frederick Handley Page's public demonstration of leading-edge slots given at Cricklewood on 21 October 1921. This encouraged him to renew his patent application. He borrowed DM 1000 from his mother to pay for wind-tunnel tests to be undertaken by Ludwig Prandtl at Göttingen University and the patent was retroactively granted as DE 347884. This gave his patent priority over those of Handley Page but a meeting between the two men settled the matter to mutual advantage, the patent rights being shared, and Lachmann being hired as a consultant by Handley Page Ltd.

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