Avro 643 “Cadet Mk.II”
[Avro 643 “Cadet Mk.II” (VH-PRU, Ag-25) on display on 5/13/2001 at the Fantasy of Flight Air Museum, Polk City, Florida. (John Shupek photos copyright © 2001 Skytamer Images)]
Avro 643 “Cadet Mk.II” Overview 
Avro 643 Cadet
The Avro Cadet was a single-engined British biplane trainer designed and built by Avro in the 1930s as a smaller development of the Avro Tutor for civil use.
Design and Development 
The Avro 631 Cadet was developed in 1931 as a smaller, more economical, derivative of the Avro 621 Tutor military trainer, for flying club or personal use. The first prototype (G-ABRS) flew in October 1931. It was publicly unveiled at the opening of Skegness airfield in May 1932, although by this time, the first orders for the type, for the Irish Army Air Corps, had already been placed and the order for six Avro Cadets delivered.
The Avro 631 Cadet was replaced in production in September 1934 by the improved Avro 643 Cadet, which had a revised rear fuselage with a raised rear seat, retaining the 135 hp Armstrong Siddeley Genet Major 1 engine of the Avro 631. In turn, this formed the basis for the more powerful Avro 643 Mk.II Cadet; it was also strengthened and had improved parachute egress. This model entered service in 1935, and was built in the largest numbers, including 34 fitted with a tail wheel for the Royal Australian Air Force.
Operational History 
The Cadet, while smaller and more economical than the Tutor, was still more expensive to run than competing two-seat light civil aircraft and was harder to hangar because of its lack of folding wings; so was mainly used as a trainer for flying schools or the military. By far, the largest civil user was Air Service Training Ltd, which operated 17 Avro 631s at Hamble, together with a further four operated by its Hong Kong subsidiary, the Far East Aviation Co. Air Service Training also operated 23 Avro 643 Mk.II Cadets, with both these and the earlier Cadets remaining in service with Reserve Training Schools run by Air Service Training until they were impressed as ATC instructional airframes in 1941.
The other major operator was the RAAF, which acquired 34 Avro 643 Mk.II Cadets, delivered between November 1935 and February 1939. These remained in service until 1946, when the surviving 16 were sold for civil use. Two of these were re-engined in 1963 with 220-hp Jacobs R-755 engines for use as crop sprayers. In the U.K., only two Cadets survived the war.
Avro 631 Cadet: Initial version, powered by Armstrong Siddeley Genet Major I engine, 35 built.
Avro 643 Cadet Mk.II Specifications 
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