CHRYSLER HAS SMALLER SIREN FOR SPECIAL USES

To cover the large market for a siren less powerful than the Chrysler-Bell Victory compressed air type, but at the same time one that is thoroughly efficient, Chrysler has designed a gas model. This siren is similar in general design to the larger type except that the sound is made by passing exhaust gases from the engine into the throats of the horn, instead of using blower-impelled compressed air for this purpose.

The gas type will have a particular appeal for small towns where the range to be covered is not great enough to require the more powerful apparatus and where the municipal budget is necessarily limited. Furthermore, the smaller model will be found very valuable in cities covered by the Chrysler-Bell Victory siren as an adjunct to the main battery of sirens. Because of the tall buildings in large cities, it has been found that almost invariably small "dead spots" will develop into which it is impossible to get the required volume of sound without locating a siren in the immediate neighborhood. As these spots need to be covered only locally, it is unnecessary to use the enormous volume produced by the compressed air type of siren and the gas model will serve perfectly.

The gas siren is powered by a six-cylinder 120-horsepower Chrysler engine with 3-7/16 inches bore and 4-1/4 inches stroke, giving a piston displacement of 236 cubic inches. This engine has all the fine performance, durability and economy features that are characteristic of Chrysler power plants.

The noise is caused by a high-frequency interruption of the flow of the exhaust gases through two throats into a horn. A rotary "chopper" passes across these throats at very high speed and as it cuts through the escaping air stream vibrations are set up and the characteristic high-pitched whine of an air siren is produced. The chopper is driven by the engine which develops 3,400 r.p.m. The air capacity is 300 cubic feet per minute delivered at approximately 5 pounds per square inch pressure.

The siren is equipped with a turntable, operated by the engine, so that its horn can be pointed through a complete circle. The apparatus can be had either adapted to a fixed mounting or for installation on a portable carriage.

Radiator, fuel tank, ignition system, starting motor and battery are complete with the engine. The weight is approximately 1600 pounds.