6 - Heinkel HD 36 (1927-1940)
the War Flying School (F 5) at Ljungbyhed was founded in 1927, general
orders were issued regarding the training programme. This was to be
divided into four phases:
- Ab-initio training.
- Secondary training (during heavier conditions, flying in formation and in
- Practice exercises and aerial reconnaissance.
- Elementary naval flying.
to meagre appropriations from the Parliament, the Air Staff planned to
purchase one standard type of aircraft which could be used for phases
I-III. This was unfortunately not a very realistic solution. On the
contrary, it created big problems for a long time.
1927, a Heinkel HD 36 was bought directly from Germany (HD = Heinkel
Doppeldecker). The HD 36 design was a further development of the HD 35 (Sk
5), of which one single aircraft was
purchased for evaluation. The Sk 5 was found too heavy and with a
too low-powered engine. The HD 36, designated Sk
6 (SwAF/n 569), was powered with
a somewhat stronger engine - the Mercedes D.IIIa,
delivering 180 hp. The Sk 6 type was intended to be the universal
for the Air Force Flight Academy.
the single Sk 6 was bought from Heinkel in Germany, the rights for
license production in Sweden were also secured. Airframes were to be
manufactured at CFM - Centrala Flygverkstaden i Malmslätt (the Central
Aircraft Workshop at Malmslätt), belonging to the Air Force. Earlier
purchased surplus Mercedes engines of 160 hp were to power the
Swedish-built aircraft. As the original HD 36 performed badly in some
respects, CFM made some alterations to the design. This did not entirely
cure the problems, but the aircraft was yet approved.
aircraft were built by CFM in two batches of ten aircraft each. They
were delivered to F 5 in 1929 and in 1930. But the engines caused
problems from the beginning. The engines, all with long running times,
were unreliable. In the beginning of 1931, longer flights were
forbidden. In less than a month, eleven force landings had been made due
to engine troubles.
To solve the problem, the engines were replaced. Armstrong Siddeley Puma engines of 240 hp were installed in all aircraft. The designation of the aircraft was changed to Sk 6A. The Puma engines were unused, but as they were bought as surplus, they were far from new. A thing that soon showed itself. The Sk 6A was never used for basic (type I) training. Most of them were disassembled and stored after a couple of years. Before that, they were used mostly used for the training of observers.
Photo at top: Sk 6, SwAF/n 569 (marked "41") with skis.
Photo: below: Sk 6A, SwAF/n 575, at Malmslätt. Both photos via Lars E. Lundin, Västervik.
Sk 6A: Length: 7,50 m. Span:10,97 m. MTOW 1.250 kg. Max. speed: 130 km/h.
© Lars Henriksson