Rocket Engine, Liquid Fuel, Cutaway, LR2-RM-4, for Lark Missile

This is a cutaway of a two-chambered liquid-fuel rocket engine for the U.S. Navy's Lark surface-to-air missile. The larger chamber produced 400 pounds of thrust. The smaller chamber produced 220 pounds for a combined thrust of 620 pounds. The Lark motor was among the earliest regeneratively-cooled types in the U.S. and was developed by Reaction Motors, Inc.

The Lark had a range of 38 miles. It was designed in late 1944 as a defense against Japanese Kamikaze attacks in the Pacific Theatre but its development was slow. The Lark did not become operational but served as an important post-war test vehicle and saw service up to 1953. This object was donated to the Smithsonian by the Reaction Motors Division of the Thiokol Chemical Corporation in 1985.