Avro 621 Tutor and Variants

For a description of the format and data included in Production Tables, see here.

Contents

Type Description

• Type 621
• Two-seat primary training biplane. The equal-span, single-bay wings were fabric covered and of all metal construction, heavily staggered such that the upper mainplane rear spar was directly above the lower mainplane front spar, with spars fabricated from light steel sheet and one-piece light alloy ribs, wire braced and supported on narrow chord N-type interplane struts. Handley Page slots were standard and Frise type ailerons were fitted to the lower mainplanes only. The steel tube rectangular section fuselage was brought up to streamlined form by large fabric covered removeable inspection panels over spruce formers; the forward fuselage encompassing the fuel tank and engine mounting was skinned in light alloy. The tailplane featured an enlarged Avian-type horn balanced rudder along with horn balanced elevators, though later aircraft featured an aerodynamically balanced rudder of elliptical form. Twin oil damped rubber in compression undercarriage shock absorbers were housed in wide streamlined fairings, the split undercarrige being V-braced back to the aircraft centreline. One 155 h.p. Armstrong Siddeley Mongoose IIIA (military) or IIIC (civil), or 215 h.p. Armstrong Siddeley Lynx IVC powerplant.
  All non-UK produced aircraft featured the Lynx powerplant. The Mongoose powered Type 621 was ordered into RAF service to meet Air Ministry Specification 3/30.

• Type 621 Tutor Mk.I
• Main RAF production variant to meet the requirements of Air Ministry Specifications 18/31 and 25/32 as indicated. Changes included the adoption of ailerons on all four wings, a modified slimmer undercarriage with steel springs in compression. Later production was to meet Air Ministry Specification 24/34, with low-drag undercarriage, Goodyear Airwheels, a Townend ring cowling, brakes, a tailwheel and, eventually, a tie rod between the ailerons in place of the original balance cable. One 215 h.p. Armstrong Siddeley Lynx IVC powerplant.

• Type 621 Tutor Mk.II
• One aircraft: as late production Tutor Mk.I, modified into a two bay biplane.

• Type 623
• 3-seat version of Type 621 for aerial survey duties. One 240 h.p. Armstrong Siddeley Lynx IV powerplant.

• Type 646 Sea Tutor
• Two-seat seaplane variant of Type 621 Tutor Mk.I fitted with twin floats to meet Specifications 26/32 and 26/34 as indicated.

Production Tables Index

Type 621 and Tutor - UK Built
Type 621 Trainer - Non-UK Built
Type 623
Type 646 Sea Tutor

Foreign Derivatives

Notes

1. Jackson [1] also gives an additional number of engineless airframes delivered: 303 military between 1932 and 1936, 7 civil between 1931 and 1938, for a total of 795 aircraft, though what happened to these airframes is unexplained. This addition of 310 airframes to the understood Avro production of 481 (463 Type 621, 3 Type 623 and 15 Type 646) would, however, yield a total of 791.
2. Given by Jackson [1] as VR-HAF, but this registration belonged to an Avian.
3. Although most sources give these as Typre 621, the Avro Heritage website [6] shows that they are Type 623.
4. Normally referred to as Mongoose-Tutor in RAF service, with the exception of K1797.

Production References

1. Avro Aircraft Since 1908, A.J. Jackson (Putnam, 1990)
2. 85 Years Of South African Air Force, Winston Brent (Freeworld Publications, 2007)
3. Aircraft of the Hellenic Air Force 1929-2001, D. Vogiatzis (published in Greek by the HAF, 2001) (also https://www.haf.gr/en/history/historical-aircraft/avro-621-tutor/)
4. Irish Air Corps Aircraft 1922-2007 at https://studylib.net/doc/7859875/aircraft-of-the-irish-air-service--irish
5. Canadian Military Aircraft Serial Numbers at CASPIR (Canadian Aircraft Serials Personnel Information Resource) at the Canadian Warplane Heritage Museum
6. Avrolist2 (originally from www.avroheritage.com) at https://www.secretprojects.co.uk/avrolist2.pdf
7. The K File, The Royal Air Force of the 1930s, J.J. Halley (Air-Britain Publications, 1995)
8. Polish Aircraft 1893-1939, Jerzy B Cynk (Putnam, 1971)
9. Avro An Aircraft Album, E.A. Harlin and G.A. Jenks (Ian Allen, 1973)
10. RAF Air Historical Branch: Delivery Serial Ledger (A.M. Form 622) (Dept of Archive and Aviation Records, RAF Museum, Hendon, Records MF-1)
11. RAF Air Historical Branch: RAF Aircraft Movement Card (A.M. Form 78) (Dept of Archive and Aviation Records, RAF Museum, Hendon, Records MFC-77-15-107 and -108)
12. RAF Air Historical Branch: Contract Delivery Cards (Dept of Archive and Aviation Records, RAF Museum, Hendon, Records MFC-78-8-4)