An amateur-built motor glider, designed by Jozef Borzecki. Between 1952 and 1961, Jozef Borzecki designed and built the Stratus motor glider. Initially, it was powered by an engine from a Czech chainsaw. The wings came from a Zuraw glider.
Initially it had a conventional control system with a control stick and rudder pedals, later replaced by a coupled control system designed by J. Borzecki, in which the control stick controlled the airframe in all axes (pitch, roll and yaw), which was intended to simplify flight training and provide more “comfortable” flying in amateur conditions. Between 1961 and 1966, the Stratus was operated secretly and illegally.
In the late 1960s, its reconstruction began. It received lighter wings from a Komar glider that provided better glide ratio, and a four-cylinder, two-stroke RB2 engine designed by Jozef Borzecki — these were two combined Riedel starter engines from the German Junkers Jumo 004 turbojet engine from World War II.
The rebuilt motor glider was renamed Altostratus and was first flown in 1972. It was operated until 1982.
| Wingspan | 10 m |
| Length | 5.5 m |
| Empty weight | 90 kg |
| Total weight | 160 kg |
| Maximum speed | 100 km/h |
| Minimum speed | 48 km/h |
| Powerplant | 4-cylinder two-stroke RB2 piston engine of 24 hp |
