Miss Shilling's Orifice

"ttyymmnn" (ttyymmnn) 02/22/2016 at 15:01 • Filed to: planelopnik history, planelopnik, wingspan

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Get your mind out of the gutter. It’s not what you think.

In the early days of the !!!error: Indecipherable SUB-paragraph formatting!!! and !!!error: Indecipherable SUB-paragraph formatting!!! , the mighty !!!error: Indecipherable SUB-paragraph formatting!!! engine had a nasty habit of losing power, or cutting out altogether, during high-G maneuvers or too much inverted flight. Unlike the fuel injected !!!error: Indecipherable SUB-paragraph formatting!!! engine of the !!!error: Indecipherable SUB-paragraph formatting!!! , the Merlin was fitted with an !!!error: Indecipherable SUB-paragraph formatting!!! (or carburettor, if you prefer the British spelling for a British engine), and during certain maneuvers, such as a hard pitch down of the nose, the fuel was forced upwards to the top of the float chamber of the carburetor, flooding the engine. This led to a loss of power, or a complete cutoff of the engine, which is really not something that you want to have happen in the middle of a pitched dogfight.

A permanent solution was found by using a Bendix or Rolls-Royce !!!error: Indecipherable SUB-paragraph formatting!!! , but until that unit could be developed, a stopgap solution was discovered by !!!error: Indecipherable SUB-paragraph formatting!!! , an engineer working at the Royal Aircraft Establishment at Farnborough. She devised a flow restrictor (officially called the R.A.E. Restrictor, but nicknamed “Miss Shilling’s Orifice,” the “Tilly Orifice, and “Tilly’s Diaphragm”) which limited fuel flow to the maximum the engine could use during a dogfight and, along with a revised carburetor needle, it solved the fuel flooding problem until the permanent fix could be found. Miss Shilling toured England with a group of mechanics, retrofitting the engines of the RAF fighters, with priority given to front line units. By the end of 1941, all the Merlins had been modified and were back in the fight, much to the relief of the beleaguered pilots.

Beatrice Shilling with her Norton motorcycle

Smallbear wants a modern Syclone, local Maple Leafs spammer > ttyymmnn 02/22/2016 at 15:06

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I love this particular piece of trivia :)

StingrayJake > ttyymmnn 02/22/2016 at 15:18

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Takes me back to playing Birds of Steel on 360 and getting the dreaded “float carburetor failure” message in a negative-G maneuver. Your Spitfire is suddenly a lame duck and your day is about to be ruined.

DrJohannVegas > ttyymmnn 02/22/2016 at 15:46

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As far as great British bodges go, this one is near the top. Legendary.

PorkchoPlissken > ttyymmnn 02/22/2016 at 15:55

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I still want this to be what I thought

ttyymmnn > PorkchoPlissken 02/22/2016 at 16:00

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Sorry, history is history.

ttyymmnn > DrJohannVegas 02/22/2016 at 16:04

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“bodge”

I learned a new word today. And it’s a great word.

f86sabre > ttyymmnn 02/22/2016 at 16:36

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The little clever ideas are a huge part of innovation and certainly show up on in service aircraft. Hat tip to Ms Shilling.

ttyymmnn > f86sabre 02/22/2016 at 16:41

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You should read her bio, if you haven’t. Apparently, she wouldn’t agree to marry her future husband until after he successfully lapped Brooklands at 100 mph, a feat she had already done herself. She also raced the Norton in the photograph above. She should be a member of the Jalopnette Hall of Fame.

f86sabre > ttyymmnn 02/22/2016 at 16:51

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Totally. That is impressive.