Sk 3 - Avro 504 (1926-1928)

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Swedish Air Force Trainer Aircraft Sk 3 Avro 504

Avro 504 was a simple and reliable design that was built in large numbers (more than 8.000 machines) during WWI. The type was ordered in 1913 by both the British Army (RFC) and Navy (RNAS) as a general-purpose aircraft. Its most well-known effort was the bombing of the Zeppelin sheds at Friedrichshafen on the 21th of November 1914. After a limited time of front-line service, the 504 was relegated to second-line duties. Most important was its use as a trainer aircraft.

The Swedish Navy Aviation ordered in 1923 and 1924 five Avro 504Ks in England. The 504K was the standard trainer variant with a universal engine mounting where engines of rotary, inline or radial types could be fitted. The Swedish 504Ks were equipped with rotating 130 hp Clerget engines. They were used as trainers in the winter (on frozen sea) at the Navy Flying School at Hägernäs near Stockholm. The five aircraft got the Navy numbers 6-10.

All five aircraft were transferred to the new Air Force in 1926. They were now based at the new War Flying School at Ljungbyhed. The new designation was Sk 3. Their registration numbers were changed to 072-076.  

In December 1925, the Army Aviation Company ordered an Avro 504N, which was delivered in April 1926, just before the forming of the independent Air Force.  The Avro 504N was an improved aircraft with a number of structural revisions, an improved landing gear that eliminated the central skid of earlier models (including the Navy 504Ks) and was powered with the stronger Armstrong Siddeley Lynx IV engine. This engine delivered 170 hp and eliminated the disadvantages of a rotating engine.  

The 504N got the registration number (0)64, a number it kept during its time in the Air Force. The designation was altered to Sk 3A. The aircraft was purchased for evaluation, but the Air Force decided not to buy any more aircraft of this type. The ex-army aircraft was instead used as a trainer at F 3 at Malmslätt. It was destroyed after only one year of service. In April, the Sk 3A crashed and had to be written off.  

Also the ex-navy Sk 3s had a short career in the Air Force. The pilot of 072 crashed fatally in the end of 1927. 075 and 076 were written off in the beginning of 1928 after crashes. The remaining 073 and 074 were written off in the summer of 1928 due to wear.  

Sk 3: Length: 8,97 m. Span: 10,97 m. MTOW 830 kg. Max. speed: 137 km/h.

Photo at top: The Sk 3A Avro 504N at Malmslätt (Malmen).
Photo from the late engineer Erik Svensson, Ljungskile, who made his military service in the Swedish Air Force in the late 1920's.  

Photo below: Two Avro 504K:s with the Navy numbers 6 and 7 at Malmslätt, probably in 1925. (Before they were transferred to the Air Force and became Sk 3).

Swedish Air Force Trainer Aircraft Sk 3 Avro 504

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© Lars Henriksson

Updated 2010-07-10