Avro 500

Avro

Industry	Aircraft manufacturing
Founded	1910
Founder	Alliott Verdon Roe
Headquarters	United Kingdom
Products	Military aircraft

File:Avro500 left.png

The Avro Type E, also known as the Type 500 and Type 502, represents a series of early British military aircraft. Recognised by Alliott Verdon Roe as the first truly successful design from his company, these models served as precursors to the Avro 504, a prominent aircraft during the First World War.

Development

Designed alongside the slightly earlier Avro Duigan, the Type E biplane was distinguished mainly by its larger size and the installation of a more powerful (60 horsepower (45 kW)) water-cooled E.N.V. engine. Both aircraft featured two-bay tractor biplane configurations with unstaggered, parallel-chord wings ending in rounded tips. Their deep fuselages had a rectangular cross-section and carried rectangular steel-framed stabilisers, elevators, and rudders without a fixed fin. The undercarriage consisted of two wheels mounted on a transverse leaf-spring and a long central skid extending forward beyond the propeller. This overall design became a dominant template in aircraft construction for two decades; among the earliest practical examples were the Avro 500 and the contemporary B.E.1.

Avro Duigan

Constructed by A.V. Roe for pioneering Australian aviator John Robertson Duigan in 1911, the Avro Duigan was a single-seat tractor biplane. Roe’s initial biplane design, the Avro Type D, had its maiden flight in April 1911, and the Avro Duigan represented a significant enhancement of this fundamentally effective aircraft. The fuselage adopted a square cross-section rather than triangular, simplifying assembly and enabling lower seating positions for occupants, thus providing improved protection. The wing structure employed an aerodynamically cleaner conventional two-bay support system, replacing the earlier two-and-a-half bay setup that included an additional pair of interplane struts near the fuselage. The undercarriage was simplified to a V-strut beneath the wing’s leading edge supporting a leaf-spring axle with wheels featuring covered spokes; below this was a single long skid supported by another V-strut beneath the trailing edge and a strut extending from the aircraft’s nose. The tailplane was steel-framed with rectangular fixed stabiliser, elevator, and rudder surfaces. Other components remained consistent with prior models.

The fuselage framework consisted of wire-braced ash wood with metal covering forward of the cockpits. The observer’s seat was positioned at the front, with the pilot seated behind a cutaway trailing edge, placing the forward cockpit near the aircraft’s centre of gravity. This arrangement allowed solo flights without altering balance. The wire-braced high aspect ratio wings were two-bay structures with ash spars and poplar ribs; curved wingtip ends were crafted from cane. Lateral control was achieved through wing warping. A sprung tailskid was installed beneath the rudder, while small hoops under outer interplane struts protected wingtips. Dual controls were provided, along with small "Cellon" windows to enhance downward visibility.

Initially powered by a 40 hp (30 kW) two-cylinder horizontally opposed Alvaston engine, it was soon replaced by a 35 hp (26 kW) water-cooled E.N.V. V-8 motor. Large coiled tube radiators were mounted parallel to the fuselage on each side of the front cockpit.

Flight trials using the Alvaston engine at Huntingdon racecourse were unsuccessful, with minimal lift achieved. After returning to Brooklands, installation of the E.N.V. engine allowed Duigan to perform several extended straight flights solo on 10 March 1912 despite apparent underpowering. Subsequent intensive tuning and propeller modifications in April led to improved performance including solo circuits, figure-eight maneuvers, and hour-long flights at approximately 500 ft (150 m) altitude.

Duigan earned his Aviator's Certificate before returning to Australia. His aircraft—minus its engine—was sold to the Lakes Aircraft Co., which converted it into the Lakes Sea Bird floatplane in October 1912, powered by a 50 hp (37 kW) Gnome engine; this version demonstrated good performance. The slightly larger Avro 500 model, equipped with a 60 hp (45 kW) E.N.V. engine, became Avro’s first type produced in any significant numbers.

Avro 500

The initial flight of the aircraft took place on 3 March 1912, piloted by Wilfred Parke. Although the maximum speed and climb rate fell short of initial projections, the airplane demonstrated excellent qualities in other aspects. Despite this, Roe found the performance unsatisfactory, prompting the construction of a second unit equipped with a lighter 50 hp (37 kW) Gnome air-cooled rotary engine. This version first flew on 8 May 1912 and achieved an altitude of 2,000 ft (610 m) within five minutes. On the following day, it completed a 17-mile (28 km) journey from Brooklands to Laffan's Plain in 20 minutes. That same day, the aircraft successfully fulfilled the War Office’s criteria for a "Military Aircraft," as outlined for the upcoming Military Aeroplane Competition. The authorities were sufficiently impressed to purchase this aircraft and ordered two additional units, which Roe subsequently designated as the Avro 500.

Service

The model quickly gained favor in operational use, leading to additional orders for four more units along with five single-seat variants, which Avro identified as the Type 502. Among the other units produced were six delivered to the British Admiralty's Air Department, one gifted to the Portugal government funded through public contributions, one retained by Avro as a demonstration aircraft, and another acquired by a private owner, J. Laurence Hall, who had it requisitioned by the War Office at the onset of World War I. The initial prototype was lost in a fatal accident on 29 June 1913, resulting in the death of its trainee pilot. During the early years of the war, British military forces operated Avro 500s predominantly as training aircraft. Modifications commonly made in service included the installation of ailerons and an updated rudder design.

Operators

Template:POR

• Portuguese Air Force

Template:UK

• Royal Flying Corps
  • No. 3 Squadron RFC
  • No. 4 Squadron RFC
  • No. 5 Squadron RFC
• Royal Naval Air Service

Bibliography

• Jackson, A. J. Avro Aircraft since 1908. London: Putnam, 1990. ISBN 0-85177-834-8.
• Lewis, P. British Aircraft 1809-1914. London: Putnam, 1962.
• World Aircraft Information Files, File 889 Sheet 92. London: BrightStar