01/31/2008. Remarks by Johan Visschedijk: "Hans Jacobs of the DFS designed the high-performance two-seat trainer Kranich (Crane) II in 1935 and more than thousand were built in Germany before WW II began.

In 1951, two engineers of the Szybowcowy Zaklad Doswiadczalny (SZD, Experimental Glider Establishment) at Bielsko, reconstructed blueprints for a slightly modified version, the SDZ-C Zuraw (Crane) II. The first was flown in 1952 by A. Zientek at Gdansk, and 50 were produced before production ended in 1953."