Avro 504

Avro

Industry	Aerospace
Founded	1910
Founder	A.V. Roe
Headquarters	Manchester , United Kingdom
Products	Aircraft including the Avro 504

Template:Infobox aircraft

The Avro 504 is a single-engine biplane bomber originally produced by the Avro company and also manufactured under licence by various other firms. During World War I, approximately 8,970 units were constructed, with production extending nearly two decades, establishing it as the most extensively produced military aircraft of the First World War era. In total, over 10,000 examples were built between 1913 and the end of production in 1932.

Design and development

File:Avro 504K dwg.jpg

Technical drawing

The Avro 504 took to the skies for the first time on 18 September 1913 at Brooklands, piloted by Fred "Freddie" Raynham. It was equipped with an 80 hp (60 kW) Gnome Lambda seven-cylinder rotary engine. This model evolved from the earlier Avro 500, intended primarily for training and private aviation purposes. The design featured a two-bay biplane configuration constructed entirely from wood, with a fuselage having a square cross-section.

File:Avro 504 by ndrwfgg.jpeg

Avro 504K preserved in the Shuttleworth Collection

Manufacturers

Numerous companies produced the Avro 504 under licence agreements.

• A. V. Roe and Co Ltd., Park Works, Newton Heath, Manchester; and Hamble Aerodrome near Southampton, Hampshire
• Australian Aircraft and Engineering, Sydney, New South Wales, 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, Paraná, Argentina
• Fabrica Militar de Aviones, Córdoba, 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, Ōtemachi, Tokyo, Japan
• Parnall & Sons, Bristol
• Regent Carriage, Fulham
• S. E. Saunders Ltd, East Cowes, Isle of Wight
• Savages Ltd, King's Lynn,
• SABCA, Brussels, Belgium
• The Sunbeam Motor Car Co Ltd, Wolverhampton
• TNCA at Balbuena field in Mexico City
• Yokosuka Naval Arsenal, Japan

Operational history

File:Foster Mount Avro504.jpg

Foster-mounted Lewis gun on the night fighter Avro 504K

File:StateLibQld 1 111320 Flight Commander Smith flies for the Peace Loan, 1919.jpg

Queenslander Pictorial (1919) showing "Flight Commander Smith flies for the Peace Loan"

Prior to the outbreak of the First World War, limited quantities of early models were acquired by both the Royal Flying Corps (RFC) and the Royal Naval Air Service (RNAS), and these aircraft were deployed to France at the war’s commencement. Notably, one RFC aircraft became the first British plane to be downed by German forces on 22 August 1914. The crew consisted of pilot 2nd Lt. Vincent Waterfall and navigator Lt Charles George Gordon Bayly, both serving with 5 Sqn RFC. The RNAS assembled a special flight of four 504s to execute a bombing mission against the Zeppelin manufacturing facilities at Friedrichshafen, situated on Lake Constance. On 21 November 1914, three aircraft departed from Belfort in northeastern France, each carrying four 20 lb (9 kg) bombs. Despite one aircraft being lost during the operation, the raid succeeded in hitting several key targets including airship sheds and a hydrogen production plant.

While rapidly outclassed as a combat aircraft, the Avro 504 excelled as a training platform, with production numbers soaring during the war. The principal variants produced were the 504J and the widely manufactured 504K, which featured modified engine mounts designed to accommodate various engines due to shortages. By the end of 1918, total production had reached 8,340 units.

In late 1917 and early 1918, a decision was made to adapt converted 504Js and 504Ks for use by Home Defence squadrons within the RFC. These replaced aging B.E.2c aircraft that suffered from inadequate altitude capabilities. The conversions transformed them into single-seat fighters equipped with a Lewis gun mounted above the upper wing on a Foster mounting, powered by either 100 hp (75 kW) Gnome or 110 hp (82 kW) Le Rhône rotary engines. A total of 274 modified Avro 504Js and Ks were distributed among eight home defence squadrons in 1918, with 226 still operational as fighters at war’s end.

After hostilities ceased, despite remaining the RAF’s standard trainer, many surplus Avro 504s were released for civilian and military resale. Over 300 examples of the 504K variant were registered for civil aviation in Britain alone. These aircraft found varied uses including pilot instruction, recreational flying, banner towing, and barnstorming performances—similar to postwar North American practices involving surplus trainers like the Curtiss JN-4 and Standard J-1 models. Civilian-operated Avro 504s remained active well into the 1930s.

The nascent air force of the Soviet Union, established shortly after World War I, employed both original Avro 504s and domestically produced copies known as Avrushka ("Little Avro") under the designation U-1 during early pilot training in the early 1920s. These were typically powered by Russian-manufactured versions of the Gnome Monosoupape rotary engine. Eventually replaced by what became aviation’s most prolific biplane—the Polikarpov Po-2, initially called U-2—the type served within Soviet ranks until the late 1920s and persisted longer elsewhere.

Although Avro 504s sold to China were primarily trainers, they saw combat roles during conflicts among regional warlords by functioning as bombers, with pilots manually dropping hand grenades and adapted mortar shells.

In 1925, Avro introduced an enhanced model designated the 504N, featuring a redesigned airframe with radial engines and an updated undercarriage. Following trials comparing two prototypes—one powered by a Bristol Lucifer engine and another by an Armstrong-Siddeley Lynx—the RAF selected the Lynx-powered version to succeed the aging 504K. Between 1925 and 1932, production yielded 592 units that equipped five RAF flying training schools while also serving communication roles. The 504N was exported internationally to military forces in Belgium, Brazil, Chile, Denmark, Greece, Siam, and South Africa. Licensed manufacturing also occurred in Denmark, Belgium, Canada, Siam, and Japan.

The RAF phased out its fleet of 504Ns in favor of the Avro Tutor starting in 1933; however, some continued in civilian hands until around 1940 when seven were requisitioned back into RAF service for target towing and glider towing duties.

The Avro 504 holds several notable distinctions: it was Britain's first aircraft to conduct ground strafing operations as well as its inaugural bomber over German territory. Additionally, it was the first Allied plane brought down by enemy anti-aircraft fire and served as an early flying platform for numerous future aces such as Billy Bishop.

One distinctive feature that makes the Avro 504 readily identifiable is its single skid located between its wheels—a component colloquially dubbed "the toothpick" within RAF circles.

Variants

File:Aviation in Britain Before the First World War RAE-O572.jpg

Early 504 equipped with an 80 horsepower Gnome Lambda engine

• 504: Powered by an 80 hp (60 kW) Gnome Lambda engine.

This was the initial version.

• 504A:

Featured smaller ailerons and wider struts, retaining the 80 hp (60 kW) Gnome engine.

• 504B

Adapted for the RNAS with an enlarged fin. Powered by either an 80 hp (60 kW) Gnome or Le Rhône engine.

• 504C

Single-seat anti-zeppelin variant for the RNAS, fitted with an additional fuel tank replacing the observer’s position.

• 504D

Single-seat anti-zeppelin model designed for the Royal Flying Corps, with six units produced.

• 504E

Equipped with a 100 hp (75 kW) Gnome Monosoupape engine; ten units built.

• 504F

Fitted with a 75 hp (56 kW) Rolls-Royce Hawk engine; only one unit constructed.

• 504G

A two-seat weapons training version derived from Type 504B for the RNAS. Intended as a bombing and gunnery trainer, it featured provisions for a Scarff ring on the upper longerons, although the final ten produced lacked gun mounts. Powered by an 80 hp Gnome engine. A total of 50 were delivered between June 1917 and January 1918, with 30 manufactured by Avro and 20 by The Regent Carriage Company.

• 504H

A modification of the 504C for catapult testing, equipped with an 80 hp (60 kW) Gnome engine.

• 504J

A 504A variant modified to accommodate a 100 hp (75 kW) Gnome engine.

File:First aeroplane in Iceland.jpg

This Avro 504K was the first aircraft to arrive in Iceland, brought there in 1919

• 504K

A two-seat trainer featuring a universal mount compatible with various engines. The single-seat fighter conversion (known as Comic) was used in anti-zeppelin roles. Several units were assembled in Australia by Australian Aircraft & Engineering. Powered by engines such as the 130 hp (97 kW) Clerget 9B, 100 hp (75 kW) Gnome Monosoupape, or 110 hp (82 kW) Le Rhône 9J.

File:Avro Dyack used by QANTAS ca. 1921.jpg

Qantas Avro 504K fitted with Sunbeam Dyak engine (circa 1921)

• 504K Mk.II

A hybrid trainer combining the fuselage of the 504K with undercarriage and wings from the 504N, powered by a rotary engine. Produced under licence in Mexico as the Avro Anahuac.

• 504L

A floatplane variant powered by engines including the 150 hp (110 kW) Bentley BR1, 130 hp (97 kW) Clerget, or 110 hp (82 kW) Le Rhône.

File:Avro504L1920.jpg

The 1920 model of the 504L floatplane

• 504M

A three-seat cabin biplane; only one unit constructed, powered by a 100 hp (75 kW) Gnome engine.

• 504N

A redesigned postwar two-seat trainer for the RAF featuring a 160 hp (120 kW) Armstrong Siddeley Lynx engine; 598 units produced.

File:Avro504n left.png

Left side view of the 504N

• 504O

Floatplane adaptation of the 504N, notable as the first airplane to fly beyond the Arctic Circle during the 1923 Oxford Expedition.

• 504P

A planned but unbuilt side-by-side seating version of the 504N.

• 504Q

A three-seat cabin biplane built specifically for the Oxford University Arctic Expedition; only one constructed, powered by an Armstrong Siddeley Lynx engine.

• 504R Gosport

A revised trainer featuring a lightweight structure. Five prototypes flew between 1926 and 1927 using various powerplants including a (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 production models adopting the Mongoose engine. Ten were exported to Argentina, where FMA built another hundred under licence. Twelve units were delivered to Estonia, remaining operational until 1940, along with an unspecified number supplied to Peru.

File:Avro 504R Gosport with Avro Alpha motor NACA Aircraft Circular No.49.jpg

The Avro 504R Gosport

• 504S

A two-seat trainer manufactured under licence in Japan by Nakajima Aircraft Company.

• 540

Observer training model based on the 504K for use in Japan.

• 582

Experimental derivative of the 504N featuring RAF 30 aerofoil wings, Frise ailerons on lower mainplanes, simplified "K" wing struts, and streamlined undercarriage. Converted back to standard 504N configuration in 1928 to serve as a Bristol Titan engine test platform.

• 585

Modified version of the 504R incorporating a 504N undercarriage and powered by a 90 hp (67 kW) Avro Alpha engine.

• 598 Warregull

A two-seat trainer based on the 504N intended for Australia; this model was not constructed.

• 599 Warregull II

A redesigned iteration of Type 598 that was never built.

• Yokosuka K2Y1

The Japanese-produced version of the Avro 504N, officially designated Yokosuka Navy Type 3 Primary Trainer, powered by a 130 hp (97 kW) Mitsubishi-built Armstrong Siddeley Mongoose radial piston engine; total production reached 104 units.

File:Yokosuka K2Y 1938.jpg

Yokosuka K2Y (1938)

• Yokosuka K2Y2

An improved model of K2Y1 featuring a 160 hp (120 kW) Gasuden Jimpu 2 radial piston engine. Combined production of K2Y1 and K2Y2 totaled approximately 360 units. Aircraft built by Watanabe carried the designation Watanabe Navy Type 3-2 Land-based Primary Trainer.

• U-1 (Uchebnyi – 1) Avrushka

A Russian-produced copy of the 504K, with over seven hundred units constructed.

• MU-1 (Morskoy Uchebnyi – 1)

The Russian seaplane adaptation of this design.

• Orlogsværftet Flyvemaskineværksted LB.I: Manufactured in Denmark at the Royal Naval Dockyard (Orlogsværftet).
• I1A

The Brazilian Navy’s designation for the Avro 504K.

• I2A

The Brazilian Navy’s designation applied to both the Avro 504N and its floatplane variant, the 504O.

• B.F.4

The Royal Siamese Air Force’s designation for their Avro 504N aircraft.

Operators

Template:Country data Afghanistan

• Afghan Air Force

Template:Country data Argentina

• Argentine Army Aviation Service – initially acquired 10 units directly from Avro, with an additional 34 produced under license by FMA between 1928 and 1937. These remained operational until 1938.

Australia

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

Belgium

• Belgian Air Force procured 50 British-manufactured 504Ks from 1920 to 1922, with an additional 27 constructed under license by SABCA. These were succeeded by the 504N variant, including 17 built by Avro between 1929 and 1931, alongside another 31 license-built units.

Template:Country data Bolivia

• Bolivian Air Force operated 11 Avro 504R Gosport models

Template:Country data Brazil

• Brazilian Air Force
• Brazilian Naval Aviation

Canada

• Royal Canadian Air Force

Template:Country data Chile

• Chilean Air Force
• Chilean Navy

Template:Country data Republic of ChinaTemplate:Namespace detect showall Republic of China

• Chinese Nationalist Air Force

File:Flag of the Republic of China-Nanjing (Peace, Anti-Communism, National Construction).svg China-Puppet

• Military Aviation of the Peacebuilding Army utilized at least one aircraft for training purposes.

Denmark

• Royal Danish Air Force
• Royal Danish Navy

Estonia

• Estonian Air Force

Finland

• Finnish Air Force

Greece

• Hellenic Air Force
• Hellenic Navy

Template:Country data Guatemala

• Guatemalan Air Force

British India

Template:Country data Iran

• Imperial Iranian Air Force

Ireland

• Irish Air Service
• Irish Air Corps

Japan

• Imperial Japanese Navy Air Service

Latvia

• Latvian Air Force
• Aizsargi

Template:Country data Malayan Union

Template:Country data Mexico

• Mexican Air Force
  • Locally produced versions were designated as "Avro Anáhuac"

Template:Country data Mongolia

• Mongolian People's Army Air Corps

Netherlands

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

New Zealand

• New Zealand Permanent Air Force

Norway

• Norwegian Army Air Service

Peru

• Peruvian Air Force

Poland

• Polish Air Force – operated a single Avro 504K captured from Soviet forces in 1920.

Portugal

• Portuguese Air Force
• Portuguese Navy

Template:Country data Russian Empire

• Imperial Russian Air Service

South Africa

• South African Air Force

Template:USSR

• Soviet Air Force – operated both original British-built models and Soviet-produced U-1 Avrushka copies.

Kingdom of Spain

• Spanish Navy
• Spanish Republican Navy

Sweden

• Swedish Air Force
• Swedish Navy

Switzerland

• Swiss Air Force

Siam (Thailand)

• Royal Siamese Air Force – at least 40 Avro 504N units acquired.
• Royal Thai Navy

Turkey

• Turkish Air Force – operated two aircraft

United Kingdom

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

United States

• American Expeditionary Force
• United States Army Air Service

Template:Country data Uruguay

• Uruguayan Air Force

Surviving aircraft and replicas

Australia

File:Qantas Replica Mascot Airport.JPG

Avro 504K replica bearing the Qantas livery with a Sunbeam engine, exhibited at the Qantas Domestic Terminal

File:G-BYKV-E3747 (16432335898).jpg

Avro 504K replica displayed at the RAAF Museum.

• A3-4 – This 504K model is exhibited as a static display at the Australian War Memorial located in Campbell, Australian Capital Territory. Originally assigned the serial number H2174, it was transported to Australia during 1918–19. Donated to the memorial in August 1929, it was loaned to Qantas in 1965 and refurbished to resemble Qantas’s inaugural aircraft. Subsequently restored to its original state, it was returned to the Australian War Memorial in 1987.
• Replica – A 504K replica is showcased at the Qantas Founders Outback Museum in Longreach, Queensland. Constructed in 1988 and marked as G-AUBG, this example represents Qantas’s first Avro 504K.
• Replica – Another 504K replica is on static exhibit at Sydney Airport, Sydney. Built in 1988 and bearing the registration G-AUBG, it symbolizes the initial Qantas Avro 504K.
• Replica – Displayed at the RAAF Museum in Point Cook, Victoria, this 504K features an original engine along with authentic fittings and instruments. It carries the serial number E3747.

Canada

• H2453 – This 504K is part of the static collection at the Canada Aviation and Space Museum in Ottawa, Ontario. Previously registered as G-CYFG and formerly owned by Cole Palen.
• Replica – A 504K replica is exhibited at the Base Borden Military Museum within CFB Borden, near Angus, Ontario. On loan from the Canada Aviation and Space Museum, it once held registration G-CYCK and was previously owned by J.S. Appleby.

Finland

• AV-57 – Stored at the Finnish Airforce Museum situated in Tikkakoski, Jyväskylä, this 504K remains preserved.

New Zealand

• A202 – An airworthy 504K maintained by The Vintage Aviator in Masterton, Wellington. Originally acquired by the New Zealand Permanent Air Force in 1925, it later served as a civilian aircraft.

Norway

• Unknown – This 504K is displayed statically at the Norwegian Aviation Museum located in Bodø, Nordland. It was operational from July 1921 until 1928 and has been exhibited since 1995. The aircraft is painted with registration number 103, which originally belonged to a 504A that crashed in 1919.

Russia

• Replica – An airworthy 504K currently based in Russia. Formerly exhibited at the Military Aviation Museum in Virginia Beach, Virginia, it carries serial number "H5991" and features Royal Flying Corps colors.

United Kingdom

• BK892 – This airworthy Avro 504K belongs to the Shuttleworth Collection in Old Warden, Bedfordshire. Initially assigned serial H5199, it was converted to a 504N model and sold for civilian use before being requisitioned by the RAF during World War II as a glider tug and reassigned a new serial number. Post-war, it returned to civilian status and appeared in the film Reach for the Sky.
• D7560 – Exhibited statically at London’s Science Museum, this Avro 504K features a 130hp Clerget engine from around 1917.
• H2311 – Displayed at Manchester’s Museum of Science and Industry, this Avro 504K remains part of their collection.
• Composite – At the Royal Air Force Museum London, a composite Avro 504K is on display featuring the fuselage from G-EBJE combined with wings from G-EBKN.
• Replica – Exhibited at the Brooklands Museum in Weybridge, Surrey, this replica marked G-AACA was originally built as a taxiable aircraft for the BBC TV series Wings during the 1970s. Later acquired by RAF Museum Hendon, stored at RAF Henlow, then loaned around 1987 to Brooklands Museum before being donated permanently. It has been fitted with an original rotary engine and restored to represent one of two Avro 504s operated by Brooklands School of Flying during the late 1920s and early ’30s.
• Replica – A static display of a 504J is presented at Solent Sky museum in Southampton, Hampshire. Marked C4451, it was constructed by ADJ under BAPC No. 210.
• Replica – Built by Pursang in Argentina in 2010 and later acquired by Eric Vernon-Roe (grandson of Avro founder Alliot Vernon-Roe), this replica registered as G-EROE currently flies with the Great War Display Team.

United States

• A201 – A restoration project underway for this Avro 504 is located at Blue Swallow Aircraft in Earlysville, Virginia.
• Replica – Another Avro 504 is under construction at Blue Swallow Aircraft facilities in Earlysville, Virginia.
• Replica – Undergoing restoration to airworthy condition at the Old Rhinebeck Aerodrome in Red Hook, New York, this Avro 504K has been operational since 1971.
• Replica – This Avro 504K is part of the static exhibition at the National Museum of the United States Air Force based in Dayton, Ohio. Constructed between 1966–1967 by the Royal Canadian Air Force’s Aircraft Maintenance & Development Unit, it arrived at the museum in May of 2003. Previously registered as G-CYEI.

Specifications (Avro 504K)

File:Dux U-1 - MU-1 1923.svg

Dimensioned blueprint of the Russian Avro 504K variant, nicknamed Avrushka (Little Avro) U-1/MU-1, reverse engineered by Sergey Ilyushin circa 1923

See also

• German page about the Soviet-manufactured U-1 Avrushka
• Sempill Mission

External links

• Argentine Avro 504 (in Spanish) Archived 4 March 2016 at the Wayback Machine
• Dedicated Avro 504 website
• RAF Museum Hendon/London collection page for Avro 504K
• Biplanes.de German site featuring Old Rhinebeck Aerodrome’s Avro 504 reproduction
• Biplanes.de German page showing assembly images of ORA’s Avro 504 replica
• Video on YouTube of Old Rhinebeck’s flying Avro 504 reproduction
• Avro 504 utilized in Greek military service
• Old Rhinebeck Aerodrome’s dedicated Avro 504 page