Avro 504 Explained

The Avro 504 was a First World War biplane aircraft made by the Avro aircraft company and under licence by others. Production during the war totalled 8,970 and continued for almost 20 years, making it the most-produced aircraft of any kind that served in any military capacity during the First World War. More than 10,000 were built from 1913 until production ended in 1932.^{[1] [2]}

Design and development

First flown from Brooklands by Fred "Freddie" Raynham on 18 September 1913,^[3] powered by an Gnome Lambda seven-cylinder rotary engine, the Avro 504 was a development of the earlier Avro 500, designed for training and private flying. It was a two-bay all-wooden biplane with a square-section fuselage.

Manufacturers

The following companies are recorded as manufacturing the Avro 504 under licence.^{[4] [5]}

• A. V. Roe and Co Ltd., Park Works, Newton Heath, Manchester; and at Hamble Aerodrome, near Southampton, Hants
• Australian Aircraft and Engineering, Sydney, NSW, Australia
• Bleriot and SPAD Aircraft Works, Addlestone
• The Brush Electrical Engineering Co Ltd, Loughborough
• Canadian Aeroplanes Ltd, Toronto, Ontario, Canada
• The Eastbourne Aviation Co Ltd, Eastbourne
• Aero Historic, Parana, Argentina
• Fabrica Militar de Aviones, Cordoba, Argentina
• Frederick Sage and Co Ltd, Peterborough and London
• The Grahame-White Aviation Co Ltd, Hendon Aerodrome, London
• Harland and Wolff Ltd, Belfast
• The Henderson Scottish Aviation Factory, Aberdeen
• Hewlett and Blondeau Ltd, Luton
• Humber Limited, Coventry
• Morgan and Co, Leighton Buzzard
• Nakajima Hikoki Seisaku Sho, Ohta-Machi, Tokyo, Japan
• Parnall & Sons, Bristol
• Regent Carriage, Fulham
• S. E. Saunders Ltd, East Cowes, Isle of Wight
• Savages Ltd, King's Lynn,
• Societe Anonyme Belge de Constructions Aeronautiques Haren, Brussels, Belgium
• The Sunbeam Motor Car Co Ltd, Wolverhampton
• TNCA, Balbuena field in Mexico City
• Yokosuka Naval Arsenal, Japan

Operational history

Small numbers of early aircraft were purchased by the Royal Flying Corps (RFC) and the Royal Naval Air Service (RNAS) prior to the start of the First World War, and were taken to France when the war started. One of the RFC aircraft was the first British aircraft to be shot down by the Germans, on 22 August 1914. The pilot was 2nd Lt. Vincent Waterfall and his navigator Lt Charles George Gordon Bayly (both of 5 Sqn RFC)^{[6] [7]} The RNAS used four 504s to form a special flight to bomb the Zeppelin works at Friedrichshafen on the shores of Lake Constance. Three set out from Belfort in north-eastern France on 21 November 1914, carrying four bombs each. While one aircraft was shot down, the raid was successful, with several direct hits on the airship sheds and the destruction of the hydrogen generating plant.^[8]

Soon obsolete as a frontline aircraft, it came into its own as a trainer, with thousands being built during the war, with the major production types being the 504J and the mass production 504K, designed with modified engine bearers to accommodate a range of engines to cope with engine shortages. 8,340 Avro 504s had been produced by the end of 1918.^[9]

In the winter of 1917–18 it was decided to use converted 504Js and 504Ks to equip Home Defence squadrons of the RFC, replacing ageing B.E.2cs, which had poor altitude performance. These aircraft were modified as single-seaters, armed with a Lewis gun above the wing on a Foster mounting, and powered by Gnome or Le Rhône engines. 274 converted Avro 504Js and Ks were issued to eight home defence squadrons in 1918, with 226 still being used as fighters at the end of the First World War.^[10]

Following the end of the war, while the type continued in service as the standard trainer of the RAF, large numbers of surplus aircraft were available for sale, both for civil and military use. More than 300 504Ks were placed on the civil register in Britain. Used for training, pleasure flying, banner towing and even barnstorming exhibitions (as was ongoing in North America following World War I with the similar-role, surplus Curtiss JN-4s and Standard J-1s); civil 504s continued flying in large numbers until well into the 1930s.

The embryonic air service of the Soviet Union, formed just after the First World War, used both original Avro 504s and their own Avrushka (" Little Avro") copy of it for primary training as the U-1 in the early 1920s, usually powered by Russian-made copies of the Gnome Monosoupape rotary engine. This Russian version of the 504 was replaced by what would become the most produced biplane in all of aviation history, the Polikarpov Po-2, first known as the U-2; the type remained in Soviet service till the late 1920s, and much later elsewhere.

Although Avro 504s sold to China were training versions, they participated in battles among warlords by acting as bombers with the pilot dropping hand grenades and modified mortar shells .

The improved, redesigned and radial-engined 504N with a new undercarriage was produced by Avro in 1925. After evaluation of two prototypes, one powered by the Bristol Lucifer and the other by the Armstrong-Siddeley Lynx, the Lynx-powered aircraft was selected by the RAF to replace the 504K. 592 were built between 1925 and 1932, equipping the RAF's five flying training schools, while also being used as communication aircraft. The 504N was also exported to the armed forces of Belgium, Brazil, Chile, Denmark, Greece, Siam and South Africa, with licensed production taking place in Denmark, Belgium, Canada, Siam and Japan.

The RAF's 504Ns were finally replaced in 1933 by the Avro Tutor, with small numbers continuing in civilian use until 1940, when seven were impressed into RAF service, where they were used for target- and glider-towing.

The 504 was the first British aeroplane to strafe troops on the ground^[11] as well as the first British aircraft to make a bombing raid over Germany.^[12] It was also the first Allied aeroplane to be downed by enemy anti-aircraft fire and was the first aircraft flown by many future aces, including Billy Bishop.

The 504 is easily recognisable because of the single skid between the wheels, referred to as the "toothpick" in the RAF.

Variants

• 504: 80hp Gnome Lambda engine.

Original model

• 504A:

Modified with smaller ailerons and broader struts. Gnome engine.

• 504B

Version for RNAS with larger fin. 80hp Gnome or Le Rhône engine.

• 504C

Single-seat anti-zeppelin aircraft for the RNAS. The 504C was fitted with an extra fuel tank, in place of the observer.

• 504D

Single-seat anti-zeppelin aircraft for the Royal Flying Corps. Six built.

• 504E

100hp Gnome Monosoupape engine. Ten built.

• 504F

75hp Rolls-Royce Hawk engine. One built.

• 504G

Two-seat weapons training variant of the Type 504B for the RNAS. The Avro 504G was intended as a bombing/gunnery trainer, with provision for a Scarff ring mounted on the upper longerons, though the final ten delivered had no provision for a gun. Fitted with one 80 hp Gnome powerplant. 50 built and delivered between June 1917 and January 1918. 30 built by Avro and 20 constructed by The Regent Carriage Company.

• 504H

504C modified for catapult trials. 80 hp (60 kW) Gnome engine.

• 504J

504A modified to mount a 100hp Gnome engine.

• 504K

Two-seat training aircraft. The 504K had a universal mount to take different engines. Single-seat fighter (Comic) conversion used for anti-zeppelin work. Several were assembled in Australia by Australian Aircraft & Engineering.^[13] 130hp Clerget 9B, 100hp Gnome Monosoupape or 110hp Le Rhône 9J engines.

• 504K Mk.II

Hybrid trainer based on 504K fuselage with 504N undercarriage and wings and powered by rotary engine. Built under licence in Mexico as Avro Anahuac.^[14]

• 504L

Floatplane version. 150hp Bentley BR1, 130hp Clerget or 110hp Le Rhône engines.

• 504M

Three-seat cabin biplane. Only one was ever built. 100hp Gnome engine.

• 504N

Two-seat training aircraft. Redesigned postwar trainer for RAF with 160hp Armstrong Siddeley Lynx engine. 598 built.

• 504O

Floatplane version of 504N. First aircraft to fly above the Arctic Circle in 1923 Oxford Expedition.

• 504P

Unbuilt version of the 504N with side-by-side seating.^[15]

• 504Q

Three-seat cabin biplane. The 504Q was built for the Oxford University Arctic Expedition. Only one was ever built, powered by an Armstrong Siddeley Lynx engine.

• 504R Gosport

Reworked trainer with revised, lightweight structure. Five prototypes flown 1926 to 1927 with various engines (100 hp/75 kW Gnome Monosoupape, 100 hp/75 kW) Avro Alpha, (140 hp/104 kW) Armstrong Siddeley Genet Major and (150 hp/110 kW) Armstrong Siddeley Mongoose), with the Mongoose chosen for production aircraft. Ten were sold to Argentina, with 100 more built by FMA under licence in Argentina. Twelve were exported to Estonia, remaining in service until 1940, and an unknown number to Peru.^[16]

• 504S

Two-seat training aircraft. Built under licence in Japan by Nakajima.

• 540

Observer training version of 504K for Japan.

• 582

Experimental version of 504N, with new wings of RAF 30 aerofoil section, Frise ailerons on the bottom mainplanes, wing struts reduced to a "K" arrangement and a simplified undercarriage. Converted back to 504N standard in 1928 for Bristol Titan engine test bed.

• 585

504R modified with 504N undercarriage and 90hp Avro Alpha engine.

• 598 Warregull

Two-seat trainer based on 504N for Australia, not built.

• 599 Warregull II

Redesigned version of Type 598, not built.

• Yokosuka K2Y1

Japanese version of the Avro 504N, given the long designation Yokosuka Navy Type 3 Primary Trainer, powered by a 130hp Mitsubishi-built Armstrong Siddeley Mongoose radial piston engine, 104 built.

• Yokosuka K2Y2

Improved version of the K2Y1, powered by a 160hp Gasuden Jimpu 2 radial piston engine. 360 built (K2Y1 and K2Y2).^[17] Watanabe built aircraft were given the long designation Watanabe Navy Type 3-2 Land-based Primary Trainer.

• U-1 (Uchebnyi – 1) Avrushka

Russian copy of the 504K. Over 700 built.^[18]

• MU-1 (Morskoy Uchebnyi – 1)

Russian seaplane version.

• Orlogsværftet Flyvemaskineværksted LB.I – Danish production at the Royal Naval Dockyard (Orlogsværftet)^[19]

Operators

• Argentine Army Aviation Service – purchased 10 directly from Avro, with a further 34 license-built by FMA from 1928 to 1937. In service until 1938.^{[20] [21] [22]}

• Australian Flying Corps
  • No. 5 (Training) Squadron in the United Kingdom
  • No. 6 (Training) Squadron in the United Kingdom
  • No. 7 (Training) Squadron in the United Kingdom
  • No. 8 (Training) Squadron in the United Kingdom
  • Central Flying School AFC at Point Cook, Victoria
• Royal Australian Air Force
  • No. 1 Flying Training School RAAF at Point Cook
• Western Australian Airways
• Qantas (Queensland And Northern Territory Aerial Service)

• Belgian Air Force purchased 50 British-built 504Ks from 1920 to 1922, with a further 27 being built under license by SABCA^[23] These were replaced by the 504N, 17 being built by Avro in 1929–31,^[24] and 31 being built under license.^[25]

• Bolivian Air Force 11 Avro 504R Gosport

• Brazilian Air Force
• Brazilian Naval Aviation

• Royal Canadian Air Force

• Chilean Air Force
• Chilean Navy

• Republic of China Air Force

China-Nanjing

• Reorganized Republic of China Air Force operated at least one in the trainer role.

• Royal Danish Air Force
• Royal Danish Navy

• Estonian Air Force

• Finnish Air Force

• Hellenic Air Force
• Hellenic Navy

• Guatemalan Air Force

British India

• Imperial Iranian Air Force

• Irish Air Service
• Irish Air Corps

• Imperial Japanese Navy Air Service

• Latvian Air Force
• Aizsargi

• Mexican Air Force
  • Models made in Mexico were called "Avro Anáhuac"

• Mongolian People's Army Air Corps

• Dutch Army Aviation Group –
• Royal Netherlands East Indies Army Air Force

• New Zealand Permanent Air Force

• Norwegian Army Air Service

• Peruvian Air Force

• Polish Air Force – 1 Avro 504K (captured from the Soviets in 1920).^[26]

• Portuguese Air Force
• Portuguese Navy

• Imperial Russian Air Service

• South African Air Force

• Soviet Air Force – With original British-built examples, and Soviet built U-1 Avrushka copy.

Kingdom of Spain

• Spanish Navy
• Spanish Republican Navy

• Swedish Air Force
• Swedish Navy

• Swiss Air Force

(Thailand)

• Royal Siamese Air Force – 40 Avro 504N (at least).^[27]
• Royal Thai Navy

• Turkish Air Force – Two aircraft

• Royal Flying Corps
• Royal Air Force
• Royal Naval Air Service

• American Expeditionary Force
• United States Army Air Service

• Uruguayan Air Force

Surviving aircraft and replicas

Australia

• A3-4 – 504K on static display at the Australian War Memorial in Campbell, Australian Capital Territory. It was initially given the serial number H2174 before being sent to Australia in 1918–19. It was donated to the memorial in August 1929. It was loaned to Qantas in 1965 and restored to resemble the first Qantas aircraft. It was restored to original condition and returned to the Australian War Memorial in 1987.^[28]
• Replica – 504K on static display at the Qantas Founders Outback Museum in Longreach, Queensland.^[29] Built in 1988, it is marked as G-AUBG and represents the first Qantas Avro 504K.
• Replica – 504K on static display at the Sydney Airport in Sydney. Built in 1988, it is marked as G-AUBG and represents the first Qantas Avro 504K.
• Replica – 504K on static display at the RAAF Museum in Point Cook, Victoria. It uses an original engine, fittings, and instruments and is marked as E3747.^[30]

Canada

• H2453 – 504K on static display at the Canada Aviation and Space Museum in Ottawa, Ontario. It was previously registered as G-CYFG and before that owned by Cole Palen.^{[31] [32]}
• Replica – 504K on static display at the Base Borden Military Museum at CFB Borden near Angus, Ontario. It is on loan from the Canada Aviation and Space Museum, was previously registered as G-CYCK, and before that was owned by J.S. Appleby.^[33]

Finland

• AV-57 – 504K in storage at the Finnish Airforce Museum in Tikkakoski, Jyväskylä.^{[34] [35]}

New Zealand

• A202 – 504K airworthy at The Vintage Aviator in Masterton, Wellington. It was purchased by the New Zealand Permanent Air Force in 1925, and subsequently operated as a civilian aircraft.^{[36] [37] [38]}

Norway

• Unknown – 504K on static display at the Norwegian Aviation Museum in Bodø, Nordland. It was in service from July 1921 to 1928 and has been on display at the museum since 1995. It is painted with the registration number 103, which belonged to 504A that crashed in 1919.^[39]

Russia

• Replica – 504K airworthy in Russia. It was previously on display at the Military Aviation Museum in Virginia Beach, Virginia.^{[40] [41]} It has been given the serial number "H5991" and is painted in Royal Flying Corps colors.

United Kingdom

• BK892 – 504K airworthy at the Shuttleworth Collection in Old Warden, Bedfordshire. It was originally given the serial number H5199, but was converted to a 504N and sold into civilian ownership. However, it was later impressed into RAF service during World War II as a glider tug, at which point it was given a new serial number. Again returned to civilian use after the war, it was used in the filming of Reach for the Sky.^{[42] [43] [44]}
• D7560 – 504K on static display at the Science Museum in London.^[45]
• H2311 – 504K on static display at the Museum of Science and Industry in Manchester.^{[46] [47]}
• Composite – 504K on static display at the Royal Air Force Museum London in London. It is made up of the fuselage of G-EBJE and the wings of G-EBKN.^{[48] [49]}
• Replica – 504K on static display at the Brooklands Museum in Weybridge, Surrey.^[50] Marked as G-AACA, it was originally built as a taxiable replica for the 1970s BBC TV series 'Wings'; later acquired by the RAF Museum, Hendon and stored at RAF Henlow then loaned to Brooklands Museum c.1987. Later donated to Brooklands Museum, fitted with an original rotary engine and restored to represent one of two 504s used by the Brooklands School of Flying in the late 1920s and early 1930s.
• Replica – 504J on static display at Solent Sky in Southampton, Hampshire.^[51] It is marked as C4451 and was built by ADJ, BAPC No 210.
• Replica-504K built by Pursang in Argentina in 2010, bought by Eric Vernon-Roe, grandson of Alliot Vernon-Roe, founder of Avro, and then to the UK. Registered as G-EROE, it displays with the Great War Display Team.

United States

• A201 – 504 under restoration at Blue Swallow Aircraft in Earlysville, Virginia.
• Replica – 504 under construction at Blue Swallow Aircraft in Earlysville, Virginia^[52]
• Replica – 504K undergoing work to airworthy at the Old Rhinebeck Aerodrome in Red Hook, New York.^{[53] [54]} It has been flying since 1971.^[55]
• Replica – 504K on static display at the National Museum of the United States Air Force in Dayton, Ohio. It was built in 1966–1967 by the Royal Canadian Air Force's Aircraft Maintenance & Development Unit and arrived at the museum in May 2003. It was previously registered as G-CYEI.^[56]

See also

• German language page on the Soviet-produced U-1 Avrushka
• Sempill Mission

Bibliography

• Andersson. Lennart. Histoire de l'aéronautique persane, 1921–1941: La première aviation du Chah d'Iran . Avions: Toute l'aéronautique et son histoire . July 1998 . 76 . 2–12 . History of the Persian Air Force, 1921–1941: The First Aircraft of the Shah of Iran . French . 1243-8650.
• Bruce . J. M.. The Avro 504: Historic Military Aircraft No. 8, Part I . . 9 July 1954. 41–44. pdf .
• Bruce . J. M.. The Avro 504: Historic Military Aircraft No. 8, Part II. . 16 July 1954. 83–88 . pdf .
• Book: Bruce, J. M.. Warplanes of the First World War – Fighter, Volume One, Great Britain . Macdonald. 1965 . London.
• Book: Donald, David. The Encyclopedia of World Aircraft. 1997. Aerospace Publishing. 1-85605-375-X.
• Gerdessen . Frederik . Estonian Air Power 1918 – 1945 . . 18 . April–July 1982 . 61–76 . 0143-5450.
• Book: Holmes, Tony . Jane's Vintage Aircraft Recognition Guide . 2005 . Harper Collins. London . 0-00-719292-4 .
• Book: Jackson, A. J. . Avro Aircraft since 1908 . 1965. Second . Putnam. 1990. London . 0-85177-834-8.
• Klaauw. Bart van der. Unexpected Windfalls: Accidentally or Deliberately, More than 100 Aircraft 'arrived' in Dutch Territory During the Great War . Air Enthusiast . March–April 1999 . 80 . 54–59 . 0143-5450.
• Lopes. Mario C.. Les avions Avro au Portugal: des inconnu aux plus célèbres. Avions. November 1999 . 80 . 36–41 . Portuguese Avro Aircraft: From the Unknown to the Most Famous. French . 1243-8650.
• Magnusson . Michael . FMA : from 1945: The Story of Fabrica Militar de Aviones, Argentina: Part 1 . Air-Britain Archive . Winter 2007 . 155–158 . 0262-4923.
• Book: Mason, Francis K. The British Fighter since 1912. 1992. Annapolis, Maryland. Naval Institute Press. 1-55750-082-7.
• Book: Mason, Francis K. The British Bomber since 1914. 1994. Putnam Aeronautical Books. London. 0-85177-861-5.
• Book: Mikesh, Robert C. . Japanese Aircraft 1910–1914. Shorzoe Abe . 1990 . Putnam. London . 0-85177-840-2 .
• Owers. Colin. Australian 504s. Air Enthusiast. 1991. 44 . 62–69 . 0143-5450.
• Prins. François. Pioneering Spirit: The QANTAS Story . . Spring 1994. 53 . 24–32 . 0143-5450.
• Book: Jane's Encyclopedia of Aviation . Taylor, M. J. H.. Jane's Publishing Company.
• Thomas . Andrew . In the Footsteps of Daedulus: Early Greek Naval Aviation . Air Enthusiast . 94 . July–August 2001 . 8–9 . 0143-5450.
• Wauthy. Jean-Luc. de Neve. Florian. amp. Les aéronefs de la Force Aérienne Belge, deuxième partie 1919–1935. Le Fana de l'Aviation . June 1995 . 305 . 28–33 . 0757-4169. fr. Aircraft of the Belgian Air Force.

External links

• Argentine AVRO 504 (Spanish)
• Avro 504 site
• RAF Museum Hendon/London
• Biplanes.de German language page with Old Rhinebeck Aerodrome's Avro 504 reproduction
• Biplanes.de German language page with assembly photos of ORA's Avro 504 reproduction
• YouTube Video of Old Rhinebeck's Avro 504 reproduction in flight
• Avro 504 in Greek service
• Old Rhinebeck Aerodrome's Avro 504 page

Notes and References

1. Web site: Avro 504 (Foreign Derivatives) . britishaviation-ptp.com . 23 January 2019.
2. Web site: Avro 504J & Avro 504K . 2022-11-17 . BAE Systems International . en.
3. Jackson 1990, p.52.
4. Flight 1954 p87
5. Web site: Gregorie . Martin C. . The Avro 504K . Martin Gregorie's Home Page . 16 July 2021.
6. "Casualty Details:Vincent Waterfall". Commonwealth War Graves Commission. Retrieved 10 January 2010.
7. Jackson 1990, p.56.
8. Mason 1994, p.21.
9. Bruce 16 July 1954, p.87.
10. Mason 1992, p.127.
11. Bruce 9 July 1954, p.43.
12. Book: Lindqvist, Sven . A history of bombing . 2001 . New Press . 1-56584-625-7 . New York . 44794868.
13. Book: Wilson. Stewart. Military Aircraft of Australia. 1994. Aerospace Publications. Weston Creek, Australia. 1875671080. 216.
14. Jackson 1990, p.105.
15. Jackson 1990, p.127.
16. Jackson 1990, p. 129-133.
17. Mikesh and Abe 1990, p. 276.
18. Jackson 1990, p. 104.
19. Web site: DANISH AIRCRAFT MANUFACTURE . ole-nikolajsen.com . 29 December 2018 . Copenhagen . 15 August 2021 . https://web.archive.org/web/20210815194359/http://www.ole-nikolajsen.com/DANISH%20MILITARY%20%20AIRCRAFT%20PRODUCTION.pdf . dead .
20. Magnusson 2007, p. 155
21. Web site: Catálogo Ilustrado de Aeronaves de la Fuerza Aérea Argentina . Ay . Carlos . es . 15 August 2013 . Gaceta Aeronautica.
22. The 504 is listed in several sources as having been used by the Argentine Air Force. This is because its predecessor, the Army Aviation Service, was established in 1912 and dissolved in 1945 when the Air Force was created.
23. Jackson 1990, p.88.
24. Jackson 1990, p.123.
25. Jackson 1990, p.124.
26. Morgała, Andrzej (1997). Samoloty wojskowe w Polsce 1918–1924 [Military aircraft in Poland 1918–1924] (in Polish). Warsaw: Lampart. p. 118. .
27. Garlicki, Jarosław (2001). Historia lotnictwa wojskowego Królestwa Tajlandii w latach 1912 – 1945. Część 2. "Militaria i Fakty". 1-2/2001, p. 34-35
28. Web site: Avro 504K two-seat biplane elementary trainer : A3-4. Australian War Memorial. 23 May 2017.
29. Web site: Qantas Founders Museum Aircraft Collection . Qantas Founders Museum . 16 July 2021.
30. Web site: Avro 504K E3747 . RAAF Museum . 16 July 2021.
31. Web site: AVRO 504K (G-CYFG). Canada Aviation and Space Museum. Canada Science and Technology Museums Corporation. 23 May 2017.
32. Web site: Hine. Colin. Canada Aviation and Space Museum Aircraft: Avro 504K RCAF Registrations: G-CYFG & G-CYCK. 23 May 2017. August 2013.
33. Web site: AVRO 504K (G-CYCK). Canada Aviation and Space Museum. Canada Science and Technology Museums Corporation. 23 May 2017. 7 January 2017. https://web.archive.org/web/20170107060217/http://casmuseum.techno-science.ca/en/collection-research/artifact-avro-504k-cyck.php. dead.
34. Web site: KUVIA BREGUET-PROJEKTISTA. Suomen Ilmavoimamuseo. 23 May 2017. fi.
35. Web site: Avro 504K. Ilmailumuseot.fi. 23 May 2017. fi.
36. Web site: Aircraft ZK-ACU Data . Airport-Data.com . 16 July 2021.
37. Web site: Airframe Dossier – Avro 504K, c/r ZK-ACU . Aerial Visuals . 16 July 2021.
38. Web site: Prince . Ivan . Cowan . Brendan . RNZAF Avro 504K 201 to 206 & RAF Serials . NZDF Serials . 16 July 2021 . 6 December 2013.
39. Web site: Avro 504. Norsk Luftfartsmuseum. 23 May 2017. https://web.archive.org/web/20160819092719/http://luftfartsmuseum.no/fly/avro-504-3/. 19 August 2016. dead.
40. Web site: WWI – Aircraft. Military Aviation Museum. Military Aviation Museum. 23 May 2017. dead. https://web.archive.org/web/20161002071155/http://www.militaryaviationmuseum.org/ww1-aircraft.html. 2 October 2016.
41. Web site: FAA REGISTRY [N504K]]. Federal Aviation Administration. U.S. Department of Transportation. 23 May 2017.
42. Web site: AVRO 504K. Shuttleworth. Shuttleworth. 23 May 2017.
43. Web site: Airframe Dossier – Avro 504K, s/n BK892 RAF, c/n R3/LE/61400, c/r G-ADEV. Aerial Visuals. AerialVisuals.ca. 23 May 2017.
44. Web site: GINFO Search Results [G-ADEV]]. Civil Aviation Authority. 23 May 2017.
45. Web site: Avro 504K biplane D7560 with 130hp Clerget engine, c 1917.. Science Museum. 23 May 2017. https://web.archive.org/web/20140703181724/http://www.sciencemuseum.org.uk/objects/aeronautics/1920-52.aspx. 3 July 2014.
46. Web site: Avro 504K Plane. Science Museum. 23 May 2017.
47. Web site: Airframe Dossier – Avro504, s/n H2311 RAF, c/n H2311, c/r G-ABAA. Aerial Visuals. AerialVisuals.ca. 23 May 2017.
48. Web site: Avro 504K. Royal Air Force Museum. Trustees of the Royal Air Force Museum. 23 May 2017.
49. Web site: Simpson. Andrew. INDIVIDUAL HISTORY [E449]]. Royal Air Force Museum. Royal Air Force Museum. 23 May 2017. 2014.
50. Web site: Avro 504K (replica) . Brooklands Museum . 16 July 2021.
51. Web site: Our Exhibits . Solent Sky . 16 July 2021.
52. News: Von Reuter. Jennifer. Company Making Antique Airplanes. 24 May 2017. NBC29.com. Frankly Media. 22 September 2009. 18 August 2018. https://web.archive.org/web/20180818052210/http://www.nbc29.com/Global/story.asp?s=11087577. dead.
53. Web site: McCullough. Patrick. Haggerty. Tim. World War I (1914–1918). Cole Palen's Old Rhinebeck Aerodrome. Rhinebeck Aerodrome Museum. 23 May 2017.
54. Web site: FAA REGISTRY [N4929]]. Federal Aviation Administration. U.S. Department of Transportation. 23 May 2017.
55. Air Progress. September 1971. 20.
56. Web site: Avro 504K. National Museum of the US Air Force. 23 May 2017. 7 April 2015.