The first true fighter developed by the Martinsyde company was the F.1 created in 1915 as a substantial two-bay biplane powered by a Rolls-Royce Mk III (later Eagle III) water-cooled V-12 engine rated at 250 hp (186.5 kW). Designed in the period before the introduction of an effective synchronisation equipment to permit the installation of a machine gun fixed to fire forward through the propeller disc, the F.1 was a two-seater in which the gunner occupied the front cockpit and had to stand to fire his 0.303-in (7.7-mm) Lewis gun ahead over the upper wing. The type first flew only in July 1917, by which time it was completely obsolete in conceptual terms, and further development was abandoned.
Next came the F.2, designed even as the construction of the F.1 was proceeding. The F.2 actually made its first flight in May 1917, some two months before that of its notional predecessor. The F.2 was another two-seater, although in this instance with a single-bay biplane wing cellule and the Hispano-Suiza 8Bd water-cooled V-8 engine rated at 200 hp (149 kW), but was also of more advanced concept with the pilot seated ahead of the gunner. This allowed the installation of what had by now become the standard armament for a two-seat fighter, namely one 0.303-in (7.7-mm) Vickers fixed forward-firing machine gun and one 0.303-in (7.7-mm) Lewis trainable rearward-firing machine gun. Trials revealed a number of limitations, and the F.2 was thereafter used only as a test bed for the Sunbeam Arab engine. Greater success attended the company’s next fighter, which started life as the F.3 single-seater designed by George H. Handasyde and paved the way for the F.4 that is generally considered to have been one of the finest fighters to emerge in World War I, even though the type was too late for full service in that conflict and would have been built in very large numbers only if the conflict had lasted into 1919.
Generally known to its manufacturer as ‘Mother’ on the basis that the F.1 had been ‘Father’, the F.3 was based conceptually on the F.2 revised to single-seat configuration with the Rolls-Royce Falcon Experimental V-12 engine rated at 285 hp (212.5 kW) and cooled by a frontal radiator. The F.3 was of typical configuration and construction for a fighter of its day, being a slightly unequal-span biplane of the single-bay type with an armament of two 0.303-in (7.7-mm) Vickers fixed forward-firing machine guns and a structure of wood covered with fabric everywhere except over the forward fuselage. The most notable features of the design were the deep fuselage with a slightly raised cockpit that put the pilot’s eyes in line with the upper wing, and the considerable attention paid to the reduction of drag for the maximum possible performance.
The F.3 made its first flight in November 1917, and proved to have excellent performance, and was later adapted with the production-standard Falcon III engine rated at 275 hp (205 kW), resulting in a slight loss of performance, but was still an exceptional type. Demand for the Falcon was higher than production, especially as the type was used in the highly successful Bristol F.2 Fighter, so it was decided to revise the F.3 for major production in a form with the Hispano-Suiza 8Fb V-8 engine rated at 300 hp (224 kW) to create the F.4 to which the Royal Air Force, which had come into existence during April 1918 as an amalgamation of the Royal Flying Corps and Royal Naval Air Service, accorded the designation Buzzard Mk I during September 1918.
The first F.4 was tested in June 1918 with the cockpit moved slightly to the rear to improve the pilot’s fields of vision and the lower wing reduced in chord, and with the Hispano-Suiza 8Fb engine revealed a maximum speed of 126 kt (145 mph; 223.5 km/h) at sea level declining to 109.5 kt (126 mph; 203 km/h) at 20,000 ft (6095 m). The other elements of the aeroplane’s performance were also impressive, and the machine had viceless flying characteristics as well as great agility.
An initial order for 150 aircraft had already been placed, and although perhaps six of these may have been completed to F.3 standard, the vast majority of the 370 or more completed aircraft were finished to the F.4 standard. Before the end of World War I in November 1918, orders for an additional 1,300 aircraft had been placed with the parent company (300 machines), Boulton & Paul (500 machines), Hooper (200) and Standard Motor (300 machines). The type also caught the attention of the Americans, who placed orders for 1,500 aircraft to be built in the USA but cancelled the contract at the time of the Armistice before a single machine had been produced.
By the end of October 1918 the RAF had received 52 F.3 and F.4 aircraft, but the type did not enter service with any squadron before the Armistice of November 1918, by which time work was well advanced on the F.4a long-range version to escort the bombers of the RAF’s Independent Force based in France. Two of the F.4 aircraft were used as courier machines by the RAF Communication Wing, which was responsible for the establishment and operation of a high-speed air link between London and Paris in the period when the Treaty of Versailles was being negotiated. Although some thought was given to making the F.4 the RAF’s standard fighter in the period after World War I, the decision eventually went to the Sopwith Snipe on the grounds that this was already available in moderately large numbers and with its lighter air-cooled rotary engine had a smaller turning radius than the F.4. This decision may have been justified as the time, but with hindsight it is possible to think that the F.4 would have been a better long-term choice as it was far more typical of the fighters that emerged during the 1920s.
Martinsyde continued to built the F.4 after the Armistice, and export sales were made to Finland (15 machines), Poland (not available), Portugal (four machines), Spain (15 machines) and the USSR (100 machines).
In 1920 Martinsyde developed the F.4A as a two-seat version of the F.4 with a two-bay wing cellule of greater span and provision in a separate rear cockpit for a gunner equipped with a single 0.303-in (7.7-mm) Lewis trainable machine gun. Five of these two-seat aircraft were sold to Spain, where both the single- and two-seat versions of the F.4 were known as F.4A aircraft. The F.4A fighters were used operationally in the Riffian War (1921/25) in which it was only with some difficulty that the Spanish contained and finally defeated a nationalist insurgency in Spanish Morocco. Ten of the Spanish aircraft were still in service at the outbreak of the Spanish Civil War (1936/39), although only seven of the machines were airworthy and flown by the air force of the Republican government on operational missions during the first four months of the war before being relegated to training duties and final retirement early in 1937.
Martinsyde went into liquidation during February 1924, and its assets were bought by the Aircraft Disposal Company that had been created after World War I to dispose of equipment now surplus to British requirements. ADC’s chief aircraft designer was John Kenworthy, who created the ADC.1 as a combination of the F.4’s airframe with the Armstrong Siddeley Jaguar air-cooled 14-cylinder two-row radial engine rated at 380 hp (283 kW) and installed in an open position at the front of the fuselage. This revised type made its maiden flight in October 1924, and although considerable interest was shown in the type by export customers, the only order to materialise was that from Latvia for eight aircraft delivered in 1926 and surviving, in the form of at least two aircraft, up to 1938.
In 1926 Kenworthy took the development of the F.4 one evolutionary step further than the ADC.1 by fitting an F.4 with the power plant of one ADC Nimbus liquid-cooled 6-cylinder inline engine rated at 330 hp (246 kW). The resulting aeroplane was generally known as the Nimbus-Martinsyde, which also included a changed upper line for the rear fuselage, and revised vertical tail surfaces including a horn-balanced rudder to differentiate it from the F.4 standard. Two unarmed prototypes were completed in time for participation in the King’s Cup air race of July 1926, and in 1927 the first of the aircraft was modified with faired main landing gear legs and a cylinder head fairing. ADC received no orders for the type and both prototypes were scrapped.
As they became surplus to British requirement, several F.4 aircraft were adapted to others standards including the Type A.Mk I conversions into two-seat long-range aircraft, Type AS.Mk I version of the Type A.Mk I with float alighting gear, Type A.Mk II conversions to four-seat cabin aircraft, and F.6 conversions as two-seat aircraft. The sole A.V.1 was manufactured for the engine designer Amherst Villiers.
The final operator list was Belgium (not available), Bolivia (not available), Canada (1), Finland (15), Ireland (1), Japan (1), Latvia (8), Lithuania (2), Poland (1), Portugal (4), Spain (22), UK (48) and USSR (100).
Martinsyde F.4 Buzzard Mk I
Accommodation: pilot in the open cockpit
Fixed armament: two 0.303-in (7.7-mm) Vickers fixed forward-firing machine guns in the upper part of the forward fuselage with synchronisation equipment to fire through the propeller disc
Disposable armament: up to 80 lb (36 kg) of disposable stores carried on one hardpoint under the fuselage and generally comprising four 20-lb (9.1-kg) bombs
Powerplant: one Hispano-Suiza 8Fb liquid-cooled V-8 piston engine rated at 300 hp (224 kW) for take-off
Fuel: 38 Imp gal (45.6 US gal; 172.75 litres)
Dimensions: span 32 ft 9.375 in (9.99 m); area 320.00 sq ft (29.73 m²); length 25 ft 5.625 in (7.776 m); height 10 ft 4 in (3.15 m); tailplane span 11 ft 1.5 in (3.39 m)
Weights: empty 1,811 lb (821 kg); normal take-off 2,325 lb (1055 kg); maximum take-off 2,398 lb (1088 kg)
Performance: maximum speed 145 mph (233.5 km/h) at sea level declining to 132.5 mph (213 km/h) at 15,000 ft (4570 m); climb to 10,000 ft (3050 m) in 7 minutes 55 seconds; service ceiling 24,000 ft (7315 m); endurance 2 hours 30 minutes