Silent Gasoline Engine Propelled Apparatus

Abstract

Problems are discussed connected with the design. construction. and operation of electrical generators and water pumps running under full load sufficiently silently to permit satisfactory sound recording. The units described were the result of demands for silent power equipment for making shots on boats, trains, bus interiors, inaccessible canyons. etc. As an example of what is sometimes required, one of the largest units was installed in the hold of a windjammer used throughout the Paramount Production “Souls at Sea” and although the microphone was at times directly above(approximately 30 feet) the spot occupied by the generator, no noises were picked up by the sound recording equipment. — Four units are described, namely, one 144-kw. Hispano Suiza, one 57-kw. Lincoln Zephyr, and one 41-kw. Ford V-8 generator, and one high-pressure Ford V-8 water pump. In each case the entire mechanical unit is rubber-mounted on a sub-frame within a semi-airtight compartment constructed of an outer shell of 22-gauge auto-body steel, four inches of sound-absorbing material with an inner lining of asbestos cloth. The entire exhaust system is water-cooled, employing special mufflers also housed within the case. One radiator, mounted outside, cools the water for the engine as well as the exhaust. All are practically automatic in operation, with electrical governors, temperature regulators, etc. The machines have been in operation approximately. fifteen months and have required very little service other than normal maintenance.