The Female Engineer Who Saved the Problematic Spitfire’s Engine and Changed the Course of the Battle of Britain

The Spitfire’s Hidden Flaw

During World War II, the Supermarine Spitfire became a symbol of British resistance. Its speed and agility made it a favorite among pilots, and the public saw it as a machine that could win battles. However, the aircraft had a serious problem that was not widely known at first.

The issue lay in its Rolls-Royce Merlin engine. During a dogfight, especially when forced into a steep dive, the engine would suddenly shut down. This flaw gave German pilots an advantage, as their Messerschmitt Bf 109s did not suffer from the same problem. British engineers struggled to find a solution, and without one, Britain faced serious difficulties in air combat.

An Urgent Problem

By 1940, the problem could no longer be ignored. The Battle of Britain was at its peak, and Spitfires were heavily relied upon to defend against German bombers and fighters. The flaw in the engine put British pilots at risk, as their planes could lose power at the worst possible moment.

The issue was even more concerning because the Royal Air Force had already produced more than 20,000 Spitfires, all equipped with the same flawed engine. Other British aircraft, such as the Hawker Hurricane and the Boulton Paul Defiant, also used the Rolls-Royce Merlin engine and had the same issue. British engineers attempted multiple solutions, but none of them worked reliably. As a result, pilots had to fight with a serious disadvantage.

A Life-Threatening Design Flaw

The problem was caused by the design of the Merlin engine’s carburetor. When a Spitfire entered a steep dive, gravity forced fuel away from the carburetor’s outlet, cutting off the engine’s power. German aircraft used fuel injection, which allowed their engines to maintain power at any angle, giving their pilots a major advantage in combat.

The best minds in British aviation, including engineers from Rolls-Royce, worked on the issue. Several attempted solutions were proposed, but they often created new complications. As time passed, the problem remained unsolved, and British pilots continued to struggle in battle.

The Unexpected Solution

In 1940, an engineer named Beatrice “Bet” Shilling provided the answer. Shilling was an expert in mechanical engineering and had been working on aircraft fuel systems. She identified the problem with the carburetor and developed a simple yet effective fix: a small, flow-restricting disc installed inside the fuel system. This device, later known as “Miss Shilling’s Orifice,” prevented fuel from being forced away during dives, allowing the engine to maintain power.

Shilling personally traveled to RAF bases to oversee the installation of her modification. Though it did not completely solve the problem, it significantly improved performance. Thanks to her work, British pilots could finally engage German aircraft on more equal terms. Her contribution played a key role in securing Britain’s air defense, helping turn the tide of the war.