DFS 228

The DFS 228 AND DFS 346​

DFS later built a single prototype of a cargo-carrying glider, the DFS 331, in 1941, but by that time the main thrust of the Institutes's work lay in the development of high-performance experimental sailplanes. The most significant of these was the DFS 228, planned as a high-altitude photoreconnaissance aircraft, to be transported to an altitude of 10,000m (32,800ft) or more and released, a rocket motor then taking it to an altitude of 23,000m (75,400ft). The rocket motor was then to have been used intermittently to maintain altitude until its fuel was exhausted, whereupon the DFS 228 would glide back to friendly territory. Depending on thermal conditions, it was confidently expect that the aircraft would be able to return from targets over 1000km (620 miles) away.

Only a few were constructed. Many test flights were made, all of them it is believed (though there are differing reports) without rocket power, and a new pressurised cabin, with the pilot in the prone position, was eventually developed and tried out just days before the war's end. Both the original cabin, in which the pilot sat upright, and the later version, which was very much more effective, were attached to the rest of the airframe by explosive bolts. Set free, the nose cone deployed a parachute until the outside temperature and pressure reached life-supporting levels, whereupon his seat or couch was ejected by compressed air and he made a normal parachute descent.

A development of the DFS 228, the DFS 346, was designed as a supersonic trials aircraft. It was to have had two motors, variable-chord swept wings and a Mutlhoop-stye T-tail, but was otherwise similar to the DFS 228 in its later incarnation, although constructed entirely of stressed aluminium rather than wood. An unpowered prototype was to have been built (in wood). It is believed that this aircraft and a number of somewhat modified DFS 346s were constructed in the Soviet Union after the war, and there are persistent but unsubstantiated claims that the former was the first aircraft to exceed the speed of sound with DFS test pilot Wolfgang Ziese at the controls in May 1947, some five months before Chuck Yeager's supersonic flight in a Bell X-1 on 14 October.

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