About the Monsun... In 1965 Bolkow Apparatebau's technical director, Dr. Hermann Mylius, began work on the design of a light all-metal two-seater training, aerobatics and glider towing aircraft, under the designation MHK-101. Clearly owing much to be Bo 208 Junior, with some commonality of components new wing and a wider fuselage to provide more room in the cabin. The prototype took off on its maiden flight on 22 December 1967 Powered by a 115-hp (86 kW) Lycoming O-235-C2A engine. It was developed as the Bolkow 209 Monsun and Manufacturing of a prototype began in January 1969, this making its first flight on 28 of May.

The main production variants were the Bo 209-150, powered by a 150 hp (112 kW) Avco Lycoming )-320-E1C engine driving a McCauley fixed pitch or optional Hartzell constant speed propeller, and the Bo 209-160 with a 160-hp (119-kW) AVCO Lycoming IO-320-DIA fuel injection equipped engine fitted with the Hartzell propeller as standard. Both models had folding wings to reduce hangar space requirements and to facilitate towing of the aircraft behind a car; they also had retractable nosewheels and fixed main wheels. The Monsun was also available as the Bo 209S two-seat trainer, with non-folding wings and non-retraceable landing gear. Production of all models totalling 102. ceasing in 1971.