In 1947 the British Gliding Association held a competition for a two-seat glider design. The tandem seat Harbinger was designed jointly by Waclaw Czerwiński. The Harbinger came fifth in the competition.
The Harbinger was, apart from its wing mountings, an all wood aircraft. It had braced, high-set demountable wings each built around a single main spar. These were plywood covered ahead of the spar and fabric covered behind. The inner sections, which together provided about 3.35 m of the total 18.3 m span, had constant chord and were swept forward at about 17°, partly to bring the centre of gravity forward and partly to enhance upward visibility from the rear seat. These sections were thinnest at the root, to minimise wing-fuselage aerodynamic turbulence. The outer wing panels were tapered, though the leading edges were unswept, and had elliptical wing tips. The outer panels carried ailerons and spoilers, each composed of four pairs of small square plates which rotated out above and below the wing, were situated at mid-chord across the junction between inner and outer panels.
The front member of the fuselage frame was also shared by a second, vertical square fuselage frame. The external metal tube lift struts were attached to its lower corners. The rest of the fuselage was all-wood and plywood covered, oval in cross-section and tapering toward the tail.
Length: 7,62 m
Wingspan: 18,29 m
Wing area:22 m2
Empty weight: 303 kg
Max takeoff weight: 500 kg