Packard 1A-1551 Airship Engine
Courtesy of the Chicago Museum of Science and Industry
In 1922, the Packard Motor Car Company's Model 1A-1551 was selected to power the U.S. Navy's first rigid airship, the ZR-1 "Shenandoah." The Packard design offered a more rugged construction and better fuel and oil consumption then it's rival, the Liberty 12A.
The engines can equipped with an operator's panel including acetylene primer, ignition switch, high and low il pressure gauges, and other controls. Five of Shenandoah's engines were installed in 20 foot long by six foot wide egg-shaped gondolas which were accessible in flight by way of open ladders connected to the airship's hull. Originally, a sixth engine was mounted behind the control car but was removed mid-1924 to make room for larger and more sophisticated radio equipment.
The engines could be configured either left- or right-hand so that the exhaust was ported away form the airship. They could be converted as needed by reversing cylinders and shifting parts and accessories to the other side. Cylinders were interchangeable and could be removed individually as they were attached by four crabs held by cap screws.
Packard built thirteen of these engines; four experimental gasoline-powered, low-compression engines, and nine production units which ran on aviation gasoline gravity-fed from fuel tanks mounted in the hull over the engine cars. Tetraethyl lead could be added to the fuel to reduce knocking at high power settings.
The engine on display is in left-hand configuration and is believed to be one of the original experimental units which were later upgraded to production specifications and retained as spares.
This engine is located in the Civilian Hangar near the tail of the Douglas DC-3 and is part of the airship exhibit.