c/n unknown Built 1921 and numbered ‘103’, the number being reused from and Avro 504A which had crashed in 1919. This airframe is often wrongly reported as having been ‘B5405’ in British service, however B5405 was a Sopwith Camel. The 106hp Sunbeam Dyak was a six-cylinder inline engine used to power a small number of Avro 504s due to a shortage of suitable radial engines. The Dyak was heavier and less powerful than radial alternatives such as the 160hp Armstrong Siddeley Lynx, with a detrimental effect on the aeroplane’s performance. ‘103’ was retired in 1928 and allocated to the Norwegian Technical Museum. She is now on display in the Military Aircraft Hall of the Norsk Luftfartsmuseum (Norwegian Aviation Museum). Bodø, Northern Norway 24th May 2019

The following information is from the Museum website:-

“The Avro 504K, which was specifically intended to be a trainer and flying school aircraft, came onto the market in 1918. The aircraft was used by almost all flying training establishments in the RAF. It could be fitted with many types of engine: axial, radial or rotating radial. A variant of the 504K model was fitted with a water-cooled 6-cylinder Sunbeam Dyak axial engine of 100 hp. The reason was a shortage of the more efficient and reliable radial engines. In Norway the Army Air Force had a total of five Avro 504s. The first two aircraft were the Avro 504A type and were procured in 1917. In May 1920 the Army bought two Avro 504Ks. In addition the service received one aircraft as a gift in 1922. The aircraft type was withdrawn from service in 1928. The Royal Norwegian Air Force Museum’s Avro 504K Dyak, was assembled at the Kjeller aircraft factory and delivered to the Sønnenfjeldske Flying Unit in July 1921. The aircraft was in service as a school and training aircraft until 1928. In winter it was fitted with skis. The engine was a Sunbeam Dyak. It was heavier than alternative rotary / radial engines, resulting in lower maximum speed, and less range and ceiling compared with K-models fitted with radial engines.