The Beatty-Johl BJ-2 Assegai was a single seat, high performance competition glider built in South Africa in the early 1960s.
The BJ-2 was a successor to the BJ-1, a 60 ft (18.3 m) span glider on which design began in South Africa in 1945 but abandoned before completion as it became clear that the new laminar flow airfoil sections offered better performance.
The outer pieces were trapezoidal and had 5° dihedral, changing to a non-laminar section at the tip, with the ailerons filling all their trailing edge.
The centre panel trailing edge was filled with Fowler flaps, which at maximum, 30° extension increased both the camber and the wing area, the latter by 19.5%, for low speed flight in thermals.
Forward of the wing the upper fuselage line blended smoothly into that of the single piece, sideways opening canopy to limit dive speeds.
[1][2] Camber changing Fowler flaps had been used before on gliders, notably on the 1938 Akaflieg Hannover AFH-4 and the 1948 Cijan-Obad Orao II, though not fitted to this design's later version.