The year 1941 was one of those years in history that could easily be called a “make-or-break” year. Germany had swept across the European continent since World War 2 had been declared in September 1939, taking almost every nation in its path. Hitler and his armies were attacking Russia in the east, while only England stood between the Nazis and complete control over the continent in the west. The United States had yet to enter the war, and it seemed like only a matter of time until the Germans would launch an invasion of the British Isles and end the war on that front.
All that seemed to stand in Hitler’s way was the British Royal Air Force. Hitler preferred to bomb the British into submission, as he knew that an invasion of Britain would be costly in Reichsmarks and in lives lost. And as the German Air Force, the Luftwaffe, was pounding Britain with bombs day after day, the only British response was the work of the RAF. Thus, the Battle of Britain was also the battle for Britain. Those British planes would engage and harass the Luftwaffe bombers and fighters in daily dogfights, and the British public came to realize how important those planes were to keeping the invaders from their shores. For every fighter or bomber shot down by the British, that meant a slightly better chance the Germans could not invade. Later, Prime Minister Winston Churchill would say that never in history had so many owned so much to so few; he was speaking of the brave pilots, mechanics, and crews of the RAF.
The best fighter plane the British had was the Spitfire. While the Hurricane aircraft were more numerous, the Spitfire was faster (upwards of 400mph/600kph), better built, and much more maneuverable than the Hurricane. The British plan was to destroy the German fighters that accompanied the larger bombers. If left undefended by fighters, the bombers would be much easier to pick off and shoot down. But the Germans had the Messerschmitt B-109, a worthy adversary to the Spitfire. Both machines had 12 cylinder engines, with the Spitfire’s power being supplied by the Rolls-Royce company.
And there was a major problem with the Spitfire. When the German fighters were being pursued by a Spitfire, all the German had to do was to execute a roll–a simple spin of the aircraft–and peel off from its flight path. Spitfire pilots were chagrined to find that, when the Spitfire tried the same maneuver, the plane’s engine would stall because the carburetor would flood the engine with fuel. That meant the German pilot–flying his Messerschmitt with fuel injection–could easily escape a pursuing Spitfire.
To fix this problem, the British turned to the most unlikely of sources: An engineer who had experience working on motorcycles with the improbable name of B.T. Shilling. Shilling also didn’t look the part of a war hero. Bespeckled, frumpy, and slightly pudgy, Shilling was nonetheless the foremost expert in the UK on handling problems with carburetors. Despite having a long background as a grease monkey, working on racing bikes and cars, Shilling had a masters degree in mechanical engineering. Recognizing the talent they had at their disposal in Shilling, the RAF had given the engineer the position of chief technical officer over carburetors when the war began. And now, with the Spitfire’s engine flooding problem, they turned the situation over to Shilling.
Sure enough, within a few weeks, Shilling had an answer, and it was deceptively simple. The solution was to restrict the flow of fuel to the Spitfire’s engine during the rolls and dives. That would keep the fuel from flowing into the engine too rapidly and killing it. The restrictor that Shilling designed ended up being a small, nut washer size disc with a hole in it that would be added to the fuel line in all the Spitfires. After testing the device, it was soon evident that Shilling had resolved the issue. Soon, after fitting the restrictor into the Spitfires, the German fighters couldn’t escape the power and speed of the British planes–nor could they escape the bravery of the British pilots. For the work that perhaps saved their nation, Shilling was awarded the Order of the British Empire (O.B.E.) after the war.
And the grateful mechanics and pilots, who realized how important that little device was, named the life-saving (and probably also war-saving) restrictor after its inventor.
Miss Shilling’s Orifice, they lovingly called it, after its inventor, Beatrice “Tilly” Shilling.
The Rest of the Story 