Simanaitis Says
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BROOKLANDS AND ITS SILENCERS
APPARENTLY THERE’S not enough noise in Formula 1 this year (see http://wp.me/p2ETap-28h). This got me thinking of the opposite problem: Automobile racing is inherently a very noisy activity and, occasionally, organizers have sought to quell the racket, not enhance it.
England’s traditional Brooklands motor circuit is a perfect example.
Brooklands was built in 1907 (two years before Indianapolis Motor Speedway) by Hugh Fortesque Locke King in the normally quiet little residential community of Weybridge, about 20 miles southwest of London.
One of the world’s first dedicated venues for motorsports and aviation, Brooklands is 9 miles south of London’s Heathrow Airport.
The Brooklands Outer Circuit, a portion of which still exists, was a 2.75-mile oval with some of its banking nearly 30 ft. high. Within two weeks of its official opening, on June 17 – 18, 1907, Brooklands had a 24-hour race (more than 16 years before the first running of the 24-hour race at Le Mans, France). See Grace’s Guide, http://goo.gl/2lYtFG, for other details of Brooklands events.
The Brooklands banking: under construction in 1907 and during my visit in 2008 (see http://wp.me/p2ETap-sk).
Race meetings and record attempts, of both cars and aircraft, became regular happenings, with crowds approaching 300,000. (So vast was the facility that this could still be considered “the Right Crowd, and no Crowding.”)
Weybridge neighbors seemed to accept these goings-on until September 1924, at which time they instituted an Action in His Majesty’s High Court against noise at the circuit. It wasn’t until July 2, 1925, that matters were resolved, the result being the Brooklands silencer.
The term “silencer” is the overly optimistic English term for what North Americans call a muffler. The French and Italians follow English style with silencieux and silenziatore, respectively. The Germans parallel North American literalness with Schalldämpfer (sound damper).
A Brooklands exhaust system has two chief characteristics: a rhomboidal receptacle located relatively near the engine and a fishtail exhaust at its tip. An MG Car Club article, “Brooklands Silencers—Or Do They?” by Mike Allison, offers definitive concepts, including dimensions of elements depending on engine displacement.
This chart gives dimensions of Brooklands silencers for a selection of vintage MGs, the M 12/12 through the NE. Image from “Brooklands Silencers—Or Do They?” (See http://goo.gl/kz9TAY.)
An Allison conclusion: “I have to say though that for a road car the noise levels are rather on the unsociable side.”
I once drove a 1931 MG C-Type, a two-seat sports car powered by a 746-cc single-overhead-camshaft inline-4. It had a Brooklands silencer, the rasp of which caused wonderful resonations throughout the rest of the car.
1931 MG C-Type, the proud possession of a Rob Walker relative.
At the other automotive extreme is the 4 1/2-Litre supercharged Bentley of Sir Henry “Tim” Birkin. He drove this single-seat Brooklands special to an Outer Circuit record of 137.96 mph in 1932.
The Birkin Bentley sports a proper Brooklands silencer.
Another car with a Brooklands exhaust—indeed, a trio of them!—is the fabulous 1933 Napier-Railton. See http://wp.me/p2ETap-1lR and http://wp.me/p2ETap-1m6.)
Driven by John Cobb in 1933, this car lapped the Outer Circuit at 143.44 mph, a record that stands for all time (as the circuit ceased operation in 1939).
The 1933 Napier-Railton, as driven by John Cobb—and sampled briefly by your author. Image by John Lamm.
The Napier-Railton’s powerplant is a 24.0-liter (!) broad-arrow 12-cylinder Napier Lion. Each of its three 4-cylinder banks got its own hefty exhaust, massive Brooklands can and proper fishtail.
A trio of these silencers didn’t silence very much. Image by John Lamm.
The Napier Lion engine was originally designed for Schneider Cup aircraft competition, where silencers were simply not part of the game. In fact, when the Napier-Railton set records in 1935 and 1936 at the Bonneville Salt Flats, it ran with nothing more than four stubby exhaust stacks for each of its three banks.
The Napier-Railton ran without its Brooklands silencers at the Bonneville Salt Flats.
Added bodywork shielded the driver’s eyes from the exhaust glare at night during the 24-hour record runs.
I imagine the Napier-Railton, sans its Brooklands silencers, would have had the Weybridge neighbors sitting up straight. ds
© Dennis Simanaitis, SimanaitisSays.com, 2014
Simanaitis Says 
Great to see Dennis back in print!! Kudos!! Jerold Moore
Hi, Jerold,
Many thanks for your kind words.
Actually my electronic “print” has been here since August 2012.