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.
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