
Along with the P-40 Warhawk, the P-39 Aircobra was the principal pursuit
and fighter aircraft when the U.S. entered the war. Nevertheless, it never
achieved the popularity of the Warhawk, and was used with some success as
a ground-attack aircraft. It had a 37mm cannon which fired through its
propeller spinner, and two .50 caliber and .30 caliber machine guns.
