Avro 626

Avro 626

Picture - One of seven Avro Prefects used for navigation training at RAF Andover c. 1933

Role: Trainer
Manufacturer: Avro
Designed by: Roy Chadwick
First flight: 1930
Retired: 1945
Number built: 198
Variants: Avro 621

The Avro 626 is a single engined British biplane trainer aircraft produced by Avro during the inter war period.

Design and development

The Model 626 was developed by Avro from the company's Model 621 (Tutor) for export to smaller air forces, the idea being that the 626 would be a single aircraft that could carry out general aircrew training as well as a number of other roles. The types 621 and 626 were both two-seaters, but the latter had an additional cockpit behind the rear seat of the 621 and accessible from it. This additional cockpit was fitted with a Scarff ring for a machine gun and carried equipment for air navigation, wireless and gunnery training. Structurally and aerodynamically, it was almost identical to the Tutor: it had a conventional fabric-covered, metal airframe with single bay wings. Most of the 626s, like the Tutors had an Armstrong Siddeley Lynx IVC engines of 240 hp (180 kW), but most of those supplied to the Egyptian and Brazilian Air Forces used a 260 hp (190 kW) Cheetah V from the same maker.

The usual undercarriage used split, fixed main-wheels and either a tail-skid or later a tail-wheel, but some 621s appeared on floats and on skis.

The prototype was first flown in 1930.

Operational history

Avro utilised an aggressive sales and marketing effort to introduce the Model 626 to customers throughout the world. An early production demonstration aircraft, marked G-ABFM was sent by sea to South America in 1931. After demonstrations in Buenos Aires and a record-setting flight over the Andes, the aircraft was commandeered by Argentine military officials to help quell a local uprising. The 626 performed so well that an order was immediately placed for 14 additional aircraft. The biggest users were the Air Forces of Chile, Greece, and Portugal. Numerous sales were made to foreign air forces up to 1939, some of which survived in second-line service until 1945.

The 621 was not a civil type, though some did briefly appear on the civil registers of the UK (15) and Hong Kong (6). These markings were worn for testing, demonstration and export; only two civil machines stayed on the U.K.register pre-war. After the war, two R.A.F. Prefects were civilianised, as was one in New Zealand.

Variants

Avro 626: Two seat multi-purpose aircraft
Avro Prefect : RAF and RNZAF name for the 626; in the period most RAF aircraft received names. All RNZAF Prefects had three cockpits. All the RAF machines were two-seat navigational training aircraft without the third cockpit installed.
Avro 637 : Armed patrol version of the Avro 626. Pilot had a .303 in (7.7 mm) Vickers machine gun mounted on the fuselage while the observer/gunner was armed with a .303 in (7.7 mm) Lewis Gun on an Avro low-drag mounting. This variant featured slightly larger wingspan with rounded wingtips. Eight aircraft were sold to the Kwangsi Air Force (Government of South China) in China.
Tatra T-126: Licence built 626, manufactured in Czechoslovakia; two versions produced: one with 355 hp (265 kW) Avia Rk. 17 and export version for Turkey and the Balkans with 260 hp (190 kW) Armstrong Siddeley Cheetah V

Production

198 Avro 626s and Prefects were produced.

Argentina
Received 15.
Austria
Received 7.
Belgium
12, 2 of which were still in service at the time of the German invasion in 1940..
Brazil
Received 16.
Canada
Royal Canadian Air Force - Received 12. RCAF machines featured cold weather cowlings, enclosed cockpits and skis. They were issued to No. 3 Squadron and no. 111 squadron; they survived until early World War II.
China
China Probably received 13, certainly 11. May have built one itself. All served in the Second Sino-Japanese War.
Chile
Received 20.
Czechoslovakia
Received 1. Tatra manufactured an uncertain number under licence.
Egypt
Received 27 - their first military aircraft, as distinct from DH60 Moths. Only 25 served, as two were lost in delivery and replaced Egyptian 626s served from 1933 until 1944.
Estonia
Estonian Air Force - Received 4.
Greece
Hellenic Air Force - Received 21 which were in service at the time of the Italian invasion, 3 Hellenic Air Force machines escaped the fall of Greece to join the RAF in the desert.
Ireland
Irish Air Corps - Received 4, which served until 1941.
Lithuania
Received 4. the type was still in service at the time of the Russian invasion.
New Zealand
Royal New Zealand Air Force - Received 4 Lynx-engined but three-cockpit Prefect aircraft for the RNZAF in 1935. These were used by No 1 Flying Training School. NZ203, c/n 811, survived the war and was purchased by Mr. J. Frogley in 1948 who registered it as ZK-APC. 'APC ceased flying in 1958 but in the 1980s it was acquired by the Royal New Zealand Air Force Museum and returned to the air. It is the sole surviving active 621 or Prefect.
Portugal
Portuguese Air Force and Portuguese Navy - Received 26 directly from Avro. A manufacturing licence was issued to the Portuguese factory OGMA, but it is not known how many were built by them.
Spain

Spanish Republican Air Force, An uncertain number served with the Republicans in the Spanish Civil War. These did not come direct from Avro.

United Kingdom Royal Air Force - Received 7 two-seater Prefects for air navigation training. Delivered in 1935, they operated during World War II on miscellaneous duties.

Specifications (Avro 626 (Lynx IVC engine))

Data from Avro Aircraft since 1908

General characteristics

Crew: Two
Length: 26 ft 6 in (8.08 m)
Wingspan: 34 ft 0 in (10.36 m)
Height: 9 ft 7 in (2.92m)
Wing area: 300 ft² (27.9 m²)
Empty weight: 1,765 lb (801 kg)
Loaded weight: 2,750 lb (1,247 kg)
Powerplant: 1x— Armstrong Siddeley Lynx IVC 7-cylinder radial, 210 hp (157 kW)

Performance

Maximum speed: 97 kn (112 mph, 180 km/h)
Cruise speed: 83 kn (95 mph, 153 km/h)
Range: 209 nmi (240 mi, 386 km)
Service ceiling: 14,800 ft (4,511 m)
Rate of climb: 880 ft/min (4.5 m/s)
Wing loading: 9.18 lb/ft² (44.7 kg/m²)
Power/mass: 0.076 hp/lb (0.126 kW/kg)

Bibliography

Jackson, A.J. Avro Aircraft since 1908, 2nd edition. London: Putnam Aeronautical Books, 1990. ISBN 0-85177-834-8.
Pacco, John. "Avro 626 'Prefect'" Belgisch Leger/Armee Belge: Het Militair Vliegwezen/l'Aeronautique Militaire 1930-1940. Aartselaar, Belgium, 2003, p. 83. ISBN 90-801136-6-2.

Avro 626 Pictures and Avro 626 for Sale.

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Source: WikiPedia