Beatrice Shilling OBE, aeronautical engineer and motorcycle racer, was born #OTD 1909. She invented the RAE Restrictor, a device to stop Merlin engine failure in early RAF Spitfire and Hurricane fighter planes during the Battle of Britain Luftwaffe. https://en.wikipedia.org/wiki/Beatrice_Shilling

Shilling – nicknamed ‘Tilly’ – graduated in electrical engineering from @OfficialUoM MSc in 1933. In 1936 she joined the Royal Aircraft Establishment research facility at Farnborough, balancing her job with the pretty serious hobby of motorcycle racing.

Shortly into WW2, it became clear that that RAF fighter planes had a problem. Merlin and Spitfire pilots reported issues with the Rolls-Royce Merlin engines which powered their planes. During certain deep-dive manoeuvres the engine would cut out and the plane would stall

During hard power dives (nose down, tail up), the negative g force stopped fuel getting to the engine. Turning out of the dive induced a positive g which then flooded the engine with fuel. German planes didn't have this problem, the Daimler-Benz engines used fuel injectors.

This meant German fighters were able to out-manoeuvre the RAF planes which was pretty bad.

Merlin engines used SU carburettors which weren't able to handle negative g without first starving the engine of fuel then over-compensating and flooding it https://en.wikipedia.org/wiki/SU_Carburettor

Here's a really good video from @Fiosracht which explains this problem with forces, pressure and why it was such a critical flaw

Shilling devised a metal disc (~12.5mm dia), with a hole drilled in which was fitted to the carburettor line. This restricted flow, creating sufficient pressure gradient to limit surge effects in the fuel pumps. It became known as Miss Shilling's Orifice https://en.wikipedia.org/wiki/Miss_Shilling%27s_orifice

It was a stop-gap solution, the planes didn't need to be taken out of service to be fixed. It wasn't applied to many fighters, but Shilling's understanding of the problem and the simple, rapid solution led to the development of an anti g SU carburettor.

For her war work she earned the OBE in 1948. She worked at the RAE until retirement in 1969, and she remained involved in the aerospace engineering and motorsports until her death in 1990. Today there's a Farnborough pub named in her honour https://www.jdwetherspoon.com/pubs/all-pubs/england/hampshire/the-tilly-shilling-farnborough

Shilling was also a huge gearhead and raced at Brooklands. She won the coveted Gold Star on her Manx Norton and completing a >100mph lap. According to stories she wouldn't marry her fiancé until he'd won one too! ( @GettyImages) http://cybermotorcycle.com/gallery/norton-1930s/Norton-1935-M30-Manx-Beatrice-Shilling.htm

Aaaaaand this week it was announced that @RoyalHolloway's new science building will be named the Beatrice Shilling Building! Other suggestions in the poll were Elizabeth Blackwell, Kathleen Lonsdale and Rosalind Franklin https://www.royalholloway.ac.uk/aboutus/ourcampus/estateplan/current-projects/the-beatrice-shilling-building.aspx