The Lark missile engine was a two-chambered, liquid-fuel rocket engine for the U.S. Navy's Lark ship-to-air missile. The larger chamber produced 400 pounds of thrust. The smaller chamber produced 220 pounds of thrust, or 620 pounds total. The propellants were red fuming nitric acid and aniline. The engine was among the earliest regeneratively-cooled types in the U.S., as pioneered by the manufacturer, Reaction Motors, Inc.
The cutaway, shown here, reveals the regeneratively-cooled propellant walls around the combustion chamber. The Lark was designed in late 1944 but came too late to be used in the war. It became converted to a test vehicle and was phased out about 1953. This object was found in the Smithsonian collections.