The Werfer-Granate 21, designated BR 21 in Lufwaffe manuals, is a German air-to-air rocket weapon used during the Second Weltkrieg. Developed in 1943, it consisted of a 21cm rocket mounted on underwing launchers of Luftwaffe fighters, such as the Messerschmitt Bf 109K and Focke-Wulf Fw 190D. Each rocket carried a 40.8kg high-explosive warhead capable of causing significant damage with a near miss due to its blast radius. The Werfer-Granate 21 was fired from a distance, allowing German pilots to attack the dense formations of bombers without engaging in close combat; the rocket's fuze could be configured to detonate at 600m or 1,200m, its maximum range.
When the Soviets changed tactics from massed bomber formations to fast jet bomber raids, the Werfer-Granate 21 began to be used almost exclusively for ground support. Its enormous explosive payload was similar to a battleship's guns, earning it the moniker amongst Deutsches Heer forces in the East as the "Luftwaffe Broadside".