Trp 1 - Junkers F 13 Flying Ambulance (1928-1946)

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Dr Hugo Junkers patented in 1910 his design of thick-section cantilever monoplane wings,  built in metal. During the twenties, the his F 13 low-winged aircraft with a single engine mounted in the nose and a fixed landing gear became what can be described as the most important European transport aircraft of its time. The F 13 was based on spars supported with welded duralumin tubes and covered in corrugated duralumin plating. This created a very rugged structure.  

This aircraft was strong and sturdy, easy to maintain and could be fitted with wheels, skis or floats. This made the type perfect for duties in isolated and remote areas as the interior parts of northern Sweden, a fact that the Swedish Red Cross had noticed. A F 13 aircraft was acquired and delivered to the organization in 1928.  

The F 13 was bought from AB Flygindustri (Afi), a company founded in 1925. It was located at Limhamn near Malmö in the south of Sweden. Officially, Afi was a Swedish enterprise that manufactured licence-built Junkers aircraft. In reality, it was a way for the Junkers company to pass over the restrictions concerning the manufacturing of aircraft in Germany which had been stated in the Versailles Treaty of 1919. Only 30 of the 155 aircraft delivered by Afi were built completely in Sweden.  The F 13 for the Swedish Red Cross was made by Junkers in Germany. However, the aircraft was modified for ambulance service at the factory in Sweden. Stretchers, seats for doctor and paramedic, suitable heating and ventilation etc. were installed. 

The aircraft - designated Trp 1 (later Tp 1) - was, as earlier ambulance aircraft, flown by crews from the Air Force. Two other Junkers F 13, also designated Trp 1 and given  the ”Ambulance Numbers” 2 and 3, were procured in second-hand from the civilian Swedish aviation company AB Aerotransport (ABA) in 1929.  

Ambulance No. 1 was from the beginning based at Boden in the north of Sweden. Later, it was re-based to F 4 at Frösön near Östersund. Ambulance No. 2 was also based at Frösön, while No. 3 served at F 2 at Hägernäs near Stockholm. As time went on, the three aircraft were replaced by the more powerful Trp 2 and Trp 2A (Junkers W 33 and W 34.  

The Trp 1 was fitted with a Junkers L 5 engine of 310 hp. 

Photo above of Ambulance No. 1 in 1928 at the waters outside Limhamn.

Length: 9,60 m. Span: 14,80 m. MTOW: 1.850 kg. Max. speed: 173 km/h.


Chinese air mail stamp from 1932 depicting a Junkers F 13 flying over the Great Wall Stamp from Cook Islands depiciting a Junkers F 13. To the centenary of the death of Rowland Hill, the inventor of the postage stamp. Issued 1977.
This Chinese stamp from 1932 shows a mail-carrying Junkers F 13 flying over the Great Wall of China. At least two of the 345 produced Junker F 13s were exported to China.


The Junker F 13 above (C/N J2005) was bought second-hand to South Africa in 1932 and was registered as ZS-AEA. It was used by the Union Airways, the first commercial airline in South Africa. The company was purchased by the government in 1934, which renamed it South African Airways. In 1940, the aircraft was mobilized by the South African Air Force as # 259.


Rowland Hill is most known for the reformation of the British postal system. In his pamphlet, Post Office Reform: its Importance and Practicability, he called for "low and uniform rates" according to weight, rather than distance. He made the conclusion that costs could be reduced dramatically if postage were prepaid by the sender The prepayment to be proven by the use of prepaid letter sheets or adhesive stamps. In 1840, much thanks to Hill’s work, the world's first adhesive postage stamps were distributed. The black one penny stamp, with an engraving of the young Queen Victoria, was a success from the beginning.

If he had any connections with Cook Islands? Not what I know.


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© Lars Henriksson

Updated 2013-04-30