[1] The SZD-35 Bekas is a direct development of the SZD-34 Bocian 3, a modernised Bocian with T-tail and refined aerodynamics, design of which had been completed by engineer George Kubalańca, but further design work led to the SZD-35 Bekas for export to the DDR (the former East Germany), and the abandonment of the SZD-34.

The Bekas was also designed to comply with portions of the British BCAR airworthiness requirements.

The second prototype first flew in March 1971 culminating in a destructive test of the undercarriage with the aircraft undergoing progressively harsh landings until damage occurred.

[1] To comply with the DDR requirements the structure of the Bekas was primarily of wood with plywood skinning except for a small percentage of the wing surface.

The undercarriage consisted of a sprung monowheel, set well forward of the centre of gravity, and tail-skid, which improved stability on the ground roll during winch launching but raised the cockpit sill hampering boarding the aircraft.