Avro 621

Trainer and Tutor

The Avro 621 was an all-metal conventional biplane designed by AV Roe & Company (Avro) to replace the Avro 504N in RAF service. The prototype (G-AAKT) was initially known as the Avro 621 Trainer and first flew in September 1929. It was powered by a 155 hp Armstrong Siddeley Mongoose IIIA engine and differed in a number of respects from the production variant, which was designated the Avro 621 Tutor.

 

The prototype had a triangular fin and rudder (similar to that of the Avro Avian IVM), with ailerons solely on the lower wings and an uncowled engine. Two batches of Avro 621 Trainer were ordered for the RAF to Specification 3/30 (K1230 – K1240 and K1787 – K1796 = total of 21 aircraft) for service trials. Four other Avro 621 Trainers were built, three for the Irish Air Corps and one for Australian National Airways (VH-UOL).

 

Most production aircraft were fitted with the more powerful 215 hp Armstrong Siddeley Lynx IVC engine. Two civil prototypes were flown with this engine (G-AARZ and G-AATU) resulting in the fitting of larger, more rounded, rudders. Three similar aircraft equipped with survey cameras (becoming VR-TAB, VR-TAC and VR-TAE) were sold to Tanganyika, .

 

Following the RAF service trials with the Avro 621 Trainer, a revised version, the Avro 621 Tutor was selected as the standard RAF trainer, with significant numbers ordered against Specifications 25/32 and 24/34. Changes included the adoption of ailerons on all four wings, a modified undercarriage with brakes and a tailwheel (fitted to later production aircraft). For production aircraft (after K3219), a Townend ring cowling for the Lynx IVC engine.

 

 

One aircraft (K3308) was experimentally converted to two-bay configuration and was designated the Avro 621 Mk II although it did not enter production. A seaplane version was designated the Avro 646 Sea Tutor, with 15 being delivered for use by the Seaplane Training School at Calshot. Seven engine-less Avro 646 Sea Tutor airframes were also delivered.

 

Most RAF aircraft were struck off charge in 1937. Overall production by A.V. Roe & Co Ltd comprised 436 military aircraft (RAF and export) and 49 civil machines.

 

In addition, a significant number of engine-less airframes were delivered, these totaling 303 military aircraft and 7 civil airframes. Including engine-less airframes, the total production by A.V. Roe & Co Ltd was 795 aircraft, the last of which was completed in May 1936.

 

The type was exported widely. Three Avro-built examples were delivered to Denmark, with a further 3 being built under licence locally. 30 aircraft were sold for Greek use, two were sold to Poland. 2 aircraft were sold to South Africa, where a further 57 aircraft were built under licence in Pretoria.

 

Only one aircraft survives to fly today (G-AHSA previously K3215) which is now flying with The Shuttleworth Collection at Old Warden, painted in the colours of (K3241) and the RAF Central Flying School.

 

 

Avro 621 Trainer	Mongoose-powered: prototype G-AAKT, 21 for RAF, three for Irish Air Corps, one (VH-UOL) to Australia (total 26 aircraft)
Avro 621 Tutor	Lynx-powered: Avro construction - 436 military and 49 civil machines, significant numbers of engineless airframes.
Avro 621 Tutor Mk II	One only, conversion of K3088 to two-bay biplane configuration
Licence production	Denmark (3), South Africa (57)
Total	795 (including engine-less airframes), plus 60 built under licence

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