Kalinin K-1 Soviet Passenger Aircraft

The Kalinin K-1, also recognized as RVZ-6, served as a pioneering Soviet passenger plane designed to accommodate three passengers. Initiated by Konstantin Kalinin in 1925 at the Kharkov Aviation Institute, the K-1 was a response to the demand for an economical, sturdy, and easily maintainable aircraft raised by the Ukrainian airline Ukrvozdukhput in 1923.

This high-wing, strutted monoplane featured an elliptical wooden wing covered with fabric, coupled with a tubular steel-framed fuselage covered with aluminum sheeting at the rear of the cabin and fabric at the rear fuselage. Manufactured by RVZ-6 (Remvozdhukozavod factory) in Kiev, the K-1 underwent factory testing in the summer of 1925. Subsequently, in September 1925, it successfully completed state acceptance trials in Moscow, achieving a speed of 191 km/h (119 mph; 103 kn) with a full load at 3,000 m (9,800 ft).

Post its operational deployment, the decision was swiftly made to upgrade the original 170 hp (130 kW) Salmson RB-9 engine. Opting for enhanced power and modernity, Konstantin Kalinin and his team chose the 240 hp (180 kW) BMW IV engine. The K-1 found versatile applications, functioning primarily as an airliner, later adapting to roles such as air ambulance and agricultural aircraft, capable of carrying 400 kg (880 lb) of chemicals.