In 1935 Hans Jacobs had been asked by Alexander Lippisch to become chief designer of sailplanes at the nationalised Deutsche Forschungsanstalt für Segelflug (DFS) at Darmstadt, after the closure of the RRG (Rhön-Rossitten Gesellschaft) on the Wasserkuppe in 1933.

In 1936 there was more recognition of the need for fast gliders with high wing loading and low camber to fare better in competitions by moving quickly between strong thermals; the hope was that camber-changing flaps would enhance lift in the climb.

[1] The wing was built around a single, narrow, 188 mm (7.4 in) high spar of spruce, rather than the more usual, but heavier pine, which was part of a torsion-resisting D-box formed by the plywood skin forward of it and around the leading edge.

Airbrakes were fitted at mid-chord on the innermost position on the outer panels, opening both above and below the wing but unusual in having a longer span lower blade.

[1] The first real tests of the Reiher came from Hanna Reitsch's experiences with it at the 1937 International Championships at the famous Wasserkuppe glider field in the Rhön Mountains, which revealed worrying wing flexure, heavy ailerons and unpredictable airbrakes.

[2] In 1938 the prototype, stiffened and heavier, was flown into first place by Wolfgang Späte in the same event and in 1939 the Reiher III won there in the hands of Erwin Kraft.