The Chrysler Air Raid Siren was the size of a car.
It measured twelve feet long and six feet high, and weighed an estimated 3 short tons.
The compressed air exited through six giant horns with a velocity of 400 miles per hour.
This resulted in an incredibly loud sound of 138 dB, measured 100 feet from the siren.
The loudness of this siren remains unmatched by any warning unit ever produced.
Men testing the Chrysler-Bell Victory Siren in RCA, New York.
The siren was built by the automobile company Chrysler in collaboration with Bell Telephone Laboratories.
Chrysler producedthree popularair raid sirens based on the Bell design.
The early designs used a 140 horsepower engine.
An improved version of the Chrysler Air Raid Siren with a 180 horsepower engine was introduced in 1952.
The Big Red Whistles, as they were nicknamed, were sounded only a few times during routine tests.
Its scream was reportedly heard 25 miles away.
Both the US Navy and RAF engineers experimented with different techniques of fog dispersal.
The Britisheventually used firesto evaporate the fog away.
Another method employed a series of Chrysler Air Raid Sirens installed about 100 feet apart along the planes approach.
The noise was also harmful to animals and birds in the sky.
The last Chrysler Air Raid Siren was manufactured in 1957.
Many sirens were pulled down from the top of watchtowers and buildings and repurposed into hot rod engines.
Others were sold for scrap.
A handful of them exist at their original location, but rusted and beyond salvage.
