De SCHELDE S-21. Designed in 1939 by the late Mr. Th. Slot, the prototype Dutch De Schelde S-21 was nearing completion when the Germans occupied the works in 1940, and it never flew. It was to have had a 1,085-h.p. Daimler-Benz DB-600G pusher engille with which a top speed of 367 m.p.h. was estimated. Armament consisted of two 7.7-mm. and two 23-mm. guns, two firing forward and two aft. One 23-mm. gun was positioned to fire through the propeller boss.