Soviet Bereznyak-Isayev BI-1
Several major combatants in the war experimented with rocket-assisted or rocket-powered aircraft including the Soviet Union. The result was the Bereznyak-Isayev BI-1.
After invading the Soviet Union in 1941 Germany attacked Soviet cities mercilessly with waves of bombers. Moscow’s engineers had completed plans for a rocket plane that could interdict bomber squadrons quickly by spring of that year, but Soviet leader Josef Stalin did not give authorization until after Germany invaded in June.
After the invasion began, Stalin ordered engineers Alexander Bereznyak and Aleksei Isayev to get the plane ready as soon as possible. As such, it only took 35 days to build a functional prototype. Development continued into 1942 with rocket motor tests, but engineers discovered that the BI-1 could only stay aloft for 15 minutes after the pilot ignited the rocket on the ground, which was a major limitation.
After a third prototype blew up during midair during a level flight, developers came to realize the rocket plane had another flaw: The frame, which was made of plywood and metal, could not handle what was near-supersonic flight speeds. By then, however, the war was finally turning against the Germans and in favor of the Soviets so that effectively ended development of rocket planes for homeland defense.