Avro 504J &
Avro 504K

The Avro 504J and 504K were the primary training aircraft used during the First World War, built in greater numbers than any other British aircraft of the period.
Avro 504J B3168 AV Roe built Avro 504J B3168 is an Avro 504J built by AV Roe & Co Ltd.
First flown at Brooklands in 1913 and still in RAF service in 1944, the Avro 504 was a development of the Avro 500. It was built in greater numbers than any other British aircraft during the First World War.
Ultimately built by at least 18 contractors, the total number built during the First World War is unclear, although there is general agreement that more than 8,000 were built during the First World War and the grand total, including aircraft built overseas exceeds 10,000 aircraft. The numbers quoted in this entry follow those presented at www.britishaviation-ptp.com/avro504.html.
Early models of the Avro 504 (prototype to Avro 504H, and the Avro 504N to 504R) are described separately.
Avro 504J and Avro 504K: From mid-1915 onward, the Avro 504 was withdrawn from operations in France and became the standard training aircraft for the Royal Flying Corps (RFC) and the Royal Naval Air Service (RNAS). The most significant versions of the Avro 504 were the 504J used the 100hp Gnome Monosoupape or the 80hp Le Rhone rotary engine, whereas the 504K could accommodate these and a wide range of other engine types.
The Avro 504J (of which 2,070 were built) was in essence, an Avro 504A fitted with a 100 hp Gnome Monosoupape engine. Many aircraft initially ordered as Avro 504A were eventually completed as the Avro 504J. Valuable work was performed by the Smith-Barry School of Special Flying at Gosport using the Avro 504J and 504K, formalising the instructional syllabus and teaching operational flying techniques to prepare pilots for combat flying at the Front
Towards the end of 1917, the shortage of rotary engines for Avro 504s became acute and so a modified engine mount arrangement was designed whereby different interface plates would allow many types of rotary engines to be fitted within a smooth circular cowling. This model received the designation Avro 504K.
Avro 504K A3-4 Canberra Avro 504K A3-4 on display at the Australian National War Memorial, Canberra.
Engine choices for the 504K included the 100 hp Gnome Monosoupape, the 80 or 110 hp Le Rhone, and the 130 hp Clerget, among others. The Avro 504K was the most successful version of the Avro 504, with a grand total of 4,997 being built.
In late 1917, single-seat converted 504Js and 504Ks were used to equip several Home Defence squadrons of the RFC. These aircraft were fitted with a Lewis gun above the wing and powered by 100 hp Gnome or 110 hp Le Rhône engines. 274 converted Avro 504Js and Ks were in use by eight Home Defence squadrons in 1918.
After the end of the war, the type continued in service as the standard trainer of the newly formed RAF until the late 1920s. The last UK-built Avro 504Ks were delivered in February 1927.
Large numbers of surplus aircraft were made available for sale via the Aircraft Disposal Co (Airdisco) for civil or military use whilst more than 300 504Ks were placed on the civil register in Britain and used for tuition and joy-riding. Most of these aircraft had the dual controls removed and the rear cockpit modified to accommodate two passengers.
After the War, a variety of derivative machines were produced from war surplus machines by a host of independent operators and these were used for joy riding and accounted for the popularisation of aviation all over Britain as the type gave many members of the public their first experience of an aeroplane flight.
Notable operators, included: Berkshire Aviation Co Ltd, Bournemouth Aviation Co. Ltd (five aircraft); Central Aircraft Co. Ltd (eight); C.L. Pashley; Cornwall Aviation Co Ltd, Eastbourne Aviation Co. Ltd; The Grahame-White Aviation Co. Ltd (twelve); Handley Page Ltd; Kingsbury Aviation Co. Ltd; London & Provincial Aviation Co. Ltd; Navarro Aviation Co. Ltd (three); and Vickers Ltd (four), together with many smaller and often transient companies.
Avro 504K - Fleet of 5 joyriding aircraft Southport Part of the joy-riding fleet of Avro 504Ks operated by Avro Transport Co seen on Southport beach.
A.V. Roe & Co. Ltd also entered this market in the form of the Avro Transport Company, with aircraft based all over England and Wales. Operating bases were dispersed around the coast like an itinerary for a British beach tour and included Blackpool, Southport, Fleetwood, Morecambe, Waterloo Sands (Liverpool) and Weston super Mare.
The vast supply of surplus Avro 504 airframes that were available from the Aircraft Disposal Company and from Avro storage at Alexandra Park. These formed the basis of a bewildering range of additional variants boasting different engines and passenger arrangements. Those variable specifications and types that flew under Avro designations (other than 504) will be covered separately.
The designation Avro 504K Mk.II was applied in 1924 to an unregistered prototype aircraft that combined features of the Avro 504K with the Avro 504N. The aircraft used an Avro 504K fuselage and a surplus 100hp Gnome Monosoupape married to an Avro 504N undercarriage and wings.
Although the type was not put into production, 30 examples of a similar type were produced under licence in Mexico as the Avro Anahuac.
In addition, three surplus RAF Avro 504N (G-ADGB, G-ADGM and G-ADGN) were converted in 1935 to be powered by a 130hp Clerget engine for joy-riding, thereby becoming roughly equivalent to the original Avro 504K Mk.II. Conversion of one other aircraft (G-ADGC) was started, but not completed.
Avro 504K M-MABE Cuatro Vientos Avro 504K replica M-MABE on display at the Spanish Air Force Museum, Cuatro Vientos.
Extensive military export orders for the 504K were received and 30 or more of the type were operated by each of the following nations: Australia, Belgium, Canada, Dutch East Indies, India, Japan, Portugal and South Africa. Some 331 Avro 504K were manufactured overseas in Australia, Japan, Canada, Dutch East Indies and Belgium.
Notably, a Sunbeam Dyak-powered Avro 504K erected in Australia (G-AUBG) and it was the first aircraft to be operated by Queensland and Northern Territories Aerial Services (QANTAS), later to become Australia’s national airline.
Avro 504K replica Sunbeam Dyak Sydney Replica of Sunbeam Dyak-powered Avro 504K G-AUBG, the first aircraft operated by QANTAS.
Unofficial derivatives of the Avro 504 K were built in Japan and Russia, as follows:
K1Y: Two-seat training aircraft for the Japanese Navy, a Japanese derivative of the 504K to replace the latter in Japanese Navy service. Built by Yokosuka, Nakajima, Kawanishi (as the Type 0) and Watanabe. Designated Type 13 Landplane Trainer (K1Y1) or with twin floats the Type 13 Seaplane Trainer (K1Y2). 130 h.p. Gasuden Benz inline engine.
U-1 (Uchebnyi-1) or Avrushka (Little Avro): This was a Russian version of the 504K and was produced by the Ilyushin Design Bureau and was fitted with a 120hp M.2 engine. 674 U-1 were built with a seaplane variant designated MU-1 (73 built).
Avro 504K replica G-EROE ex LV-X430 Airworthy Avro 504K replica G-EROE ex LV-X430 photographed at Sywell, Northampton.

Avro 504K Specification

Powerplant 100hp Gnome Monosoupape 110hp Le Rhone
Span 36 ft 0 in
Maximum Weight 1,800 lb 1,829 lb
Capacity and armament Trainer: 2 crew, unarmed. Anti-Zeppelin Home Defence aircraft: single pilot, Lewis gun on centre section
Maximum Speed 83 mph at 6,500 ft 95 mph
Range / endurance 3 hours 3 hours / 250 miles

Variants & Numbers

Avro 504J Two-seat training aircraft. 100 h.p. Gnome or 80 h.p. Le Rhône engine
Avro 504K Two-seat training aircraft. As the 504J with a universal mount to take different engines. Postwar aircraft reconditioning was undertaken to Specfication 19/23 and the final production batch was to Specification 15/26.
Avro 504K Mk.II Two-seat training aircraft featuring 504K fuselage with 504N wings and undercarriage.100hp Gnome or 130hp Clerget engines. Prototype only; 30 similar aircraft built under licence in Mexico as Avro Anahuac; three similar civil conversions from Avro 504N. 
K1Y Japan K1Y Two-seat training aircraft for the Japanese Navy, a Japanese derivative of the 504K to replace the latter in Japanese Navy service.
U-1 Russia The U-1 (Uchebnyi-1) Avrushka (Little Avro) was a version of the Avro 504K developed by the Ilyushin design bureau.
MU-1 MU-1 (Morskoy Uchebnyi-1) - a seaplane version of the U-1
Totals 2,070 504J, 5,328 504K (including 331 built overseas), one 504K Mk.II plus three similar conversions from 504N, 30 Avro Anahuac, 104 K1Y (Japan), 664 U-1, 73 MU-1 (Russia). Grand total: 8,273 aircraft.


Avro 504K A3-4      Australian War Memorial in Canberra, ACT ex-H2174 www.awm.gov.au
Avro 504K H2453 Canada Aviation and Space Museum in Ottawa, Ontario. Previously registered as G-CYFG. www.ingeniumcanada.org/aviation/index.php
Avro 504K AV-57 E448 in storage at the Finnish Airforce Museum in Tikkakoski, Jyväskylä.


Avro 504K ZK-ACU Ex-NZAF 502. Airworthy with The Vintage Aviator, Foxton Pines, New Zealand.


Avro 504K 103 Sunbeam Dyak powered ex-B5405. Norwegian Aviation Museum in Bodø, Nordland. Serial 103 reallocated from an Avro 504A that crashed in 1919.


Avro 504K H5199 Airworthy at the Shuttleworth Collection in Old Warden, Bedfordshire. H5199 was converted to a 504N and became G-ADEV. Later impressed as BK892. Currently painted with serial E3273, has also flown as E3404. www.shuttleworth.org
Avro 504K D7560 On display at the Science Museum in London. www.sciencemuseum.org.uk
Avro 504K E2977 Airworthy on UK register as G-EBHB privately-owned, based RAF Henlow.
Avro 504K H2311 G-ABAA on display at the Museum of Science and Industry in Manchester. www.msimanchester.org.uk
Avro 504K E449 Composite aircraft on display at the RAF Museum Hendon. Fuselage of G-EBJE and the wings of G-EBKN. www.rafmuseum.org.uk/london/
Avro 504K Replicas
G-AUBG Sunbeam Dyak-powered Avro 504K. At QANTAS Founders Museum, Longreach, QLD, Australia. www.qfom.com.au/
G-CYCK Base Borden Military Museum at CFB Borden near Angus, Ontario. On loan from the Canada Aviation and Space Museum. www.cafconnection.ca/Borden/Facilities/Museum.aspx
E3349 Luftwaffenmuseum Berlin Gatow, Germany www.mhm-gatow.de/en/the-museum
M-MABE Spanish Air Force Museum, Cuatro Vientos, Madrid.


C4451 Avro 504J replica, Solent Sky Museum. www.solentskymuseum.org
H1968 Yorkshire Air Museum, Elvington. www.yorkshireairmuseum.org
G-EROE Airworthy, built in Argentina as LV-X430, owner Eric Alliott Verdon-Roe
D9029 On display at the National Museum of the USAF, Dayton, Ohio. Built by the RCAF Aircraft Maintenance & Development Unit. Previously registered as G-CYEI.  www.nationalmuseum.af.mil

Other information

Avro Heritage Museum (www.avroheritagemuseum.co.uk