FanPost

7/31 OT: Chrysler's Cold Warrior


Chrysler's Cold Warrior

AUGUST 7, 2013

Chrysler's Cold Warrior

The Chrysler Air Raid siren remains the loudest such device produced -- all thanks Hemi V8 power.PHOTO BY CHRYSLER

Viewed through the lens of 1950s communist paranoia, a 3-ton, 12-foot-long, V8-powered air-raid siren probably made a perverse sort of sense.

After all, civil-defense doctrine claimed Soviet bombers lumbering over the North Pole would offer enough lead time to at least notify urban populations of impending atomic incineration. All that was needed was a device able to alert a large swath of the public as quickly as possible.

Enter a uniquely American solution: the Chrysler Air Raid Siren.

Like so many engineering milestones, the siren's genesis was a product of war-time urgency: In the early 1940s, the Office of Civil Defense brought Chrysler and Bell Labs together to create a warning device capable of alerting full cities in the event of a Japanese or German surprise attack. Hundreds of conventional electric sirens could be used, but OCD wanted a machine with unprecedented range, minimizing the number that would have to be installed to warn a given population.

The result, known initially as the Chrysler-Bell Victory Siren, coupled a 140-hp Chrysler inline eight-cylinder gasoline engine with a two-stage air compressor and rotary chopper. The chopper was a rotating slotted disc that sliced the air into pulses to create sound; it was then directed through six horns. The output was a staggering 137 dB at 100 feet -- Top Fuel drag-race loud.

To spread the sound across the largest radius possible, the assembly rotated through a chain-driven turntable powered via a gear reduction system. With the engine at its approximately 3,200-rpm operating speed, the siren rotated at 2 rpm.

Hemi-powered-Chrysler-Air-Raid-Siren-assembly-line.jpg

According to Chrysler company records, approximately 350 Hemi-powered air raid sirens were built.PHOTO BY CHRYSLER

While the Chrysler-Bell siren achieved its acoustic goals, its other specs were not quite as advanced: The first production models were manually controlled. A seat was provided, requiring a single brave soul to climb aboard the monstrosity, Slim Pickens-style, rotating until the nuclear flash relieved both man and machine of duty.

Aware of the design's limitations, a final improved siren was introduced as the Chrysler Air Raid Siren in 1952. Up-grades included the use of the then-new 180-hp, 331-cubic-inch Chrysler Hemi engine and a three-stage compressor to increase output. The operator's seat was also gone, replaced by a control panel on the siren's side allowing dedicated phone lines to activate it. The device was also now even louder, rated at 138 dB at 100 feet.

The Chrysler Air Raid Siren remains the loudest siren ever produced. Its remarkable specifications include a compressor discharge volume of 2,600 cubic feet per minute at 7 psi and a residential coverage area of approximately 16 square miles. In comparison, the electric sirens commonly used today for tornado and tsunami warnings can alert about four square miles.

According to company records, approximately 350 Chrysler Air Raid Sirens were built, all by the company's Marine and Industrial Engine division in Trenton, Mich. A handful remained in service as late as the 1970s, then were scrapped. Some were acquired by museums -- including the now-defunct Walter P. Chrysler Museum in Auburn Hills, Mich. -- or fell into the hands of ambitious collectors.

Fewer still were simply left in place, the cost of removal outweighing the visual pollution. One example remains at the edge of a West Hollywood public park. Another sits on a bluff overlooking Glendale, Calif. Caked in pigeon droppings and, in at least one case, missing its engine, these rusting hulks are a reminder: At one point, even the apocalypse had a Hemi.

- See more at: http://autoweek.com/article/car-life/chryslers-cold-warrior#sthash.p9jxiRZm.dpuf