The sailplane was derived from a glider made by Glasflügel between 1980 and 1982 that was put back in production by HpH and who have modified it substantially and developed new models since.

The glider continued the Glasflügel tradition of innovation: the parallelogram control stick, combined trailing edge flaps and airbrakes, automatic trimming, heel-operated brakes, automatic control connections, the extremely easy assembly of the wings and tailplane, the parallelogram forward-opening canopy and lifting instrument panel are Glasflügel innovations largely copied by other manufacturers.

Glasflügel was financially struggling at that time, following the untimely death of Eugen Hänle, the founder of the company, in 1975.

This new production run uses the original Glasflügel moulds and jigs that fortunately were not lost with the demise of the company.

The 304 S Shark features an all new wing design using the HpH xn2 profile with the airfoil only 13.2% of the cord thickness (16.4% at the root).