Heinkel HD 36

Heinkel
Industry	Aerospace
Founded	1920s
Headquarters	Germany

Overview

The Heinkel HD 36 was a training aircraft designed in Germany during the 1920s, commissioned by the Swedish Air Force which was seeking a new trainer. After assessing the earlier HD 35, the Swedish Air Force deemed it insufficiently powered and requested improvements. In response, Heinkel adapted the HD 35 by fitting it with a Mercedes D.III engine. The HD 36 eliminated the third cockpit that had been present in both the HD 35 and HD 21, while maintaining much of the original design's structure.

Only one prototype was constructed by Heinkel and submitted for evaluation by the Swedish Air Force. Although initial testing revealed ongoing deficiencies, these were largely resolved through modifications carried out by CFM, the Air Force’s maintenance facility. Following these improvements, CFM produced two series of ten aircraft each, delivered in 1928 and 1930 under the designation Sk 6.

Persistent engine issues resulted in limitations on extended flights, prompting a decision to replace all Sk 6 engines with Armstrong Siddeley Puma units. Aircraft upgraded with these engines received the new designation S 6A. Despite these efforts, the model had a relatively brief operational lifespan and was dismantled after only a few years of service.