 Compressed air was also used to retract and deploy the landing gear and to power the built-in cannon.On 1 September 1941 the BI-1 was completed and ready for gliding tests by pilot Boris N. Kudrin as Dushkin's engine was still not ready.A few weeks later,
rival aircraft designer A.S. Yakovlev took it upon himself to tow the prototype to TsAGI for windtunnel testing.