Some early Soviet jet designs.
Yak-7R (for Reaktivny - jet-powered) was developed in 1942, using Yak-7 as a structural base. It was to be powered by 2 Merkulov DM-4S ramjets and single Dushkin D-1A liquid-fueled motor.
Yakovlev Yak-7R (Soviet Union)
Yak-3RD (for Reaktivny Dvigatel - jet engine) was developed in 1944 and intended for Glushko RD-3 rocket engine. Two design versions existed differing with cockpit arrangement.
Yakovlev Yak-3RD (Soviet Union)