WW1 Planes
An encyclopediae of 1914-18 aircraft types


From the Armstrong Whitworth Aerial Department

Armstrong Whitworth Aircraft was established as the Aerial Department of Sir W. G Armstrong Whitworth & Company engineering group, and the factories were moved to Newcastle-upon-Tyne in 1912. In 1914-1917 the company's models were famously designed by Dutch designer Frederick Koolhoven (prefix "F.K."). Best sellers were the FK3 and FK 8 observation and general purpose planes, but AW also tried a quadruplane fighter, the FK9, without much success. The company later moved to civilian planes, and was eventually merged with Armstrong Siddeley which also comprised the Gloster Aircraft Company and Hawker Aircraft. Now it's Hawker Siddeley.


The first plane of the company was the result of the British War Office asking W G Armstrong Whitworth & Co Ltd to manufacture aeroplanes and aircraft engines for the Army. Soon after the department was set up and Frederick Koolhoven in (formerly head of British Deperdussin design), a small, single-seat scout aircraft was soon created. Of single-bay tractor configuration the F.K.1 and balanced elevators and no fixed tailplane. It was powered by a 50 hp (37 kW) Gnôme although a 80 hp had been originally planned, in short supply. Koolhoven flew it personnally in September 1914 but as suspected it was underpowered. Modifications included a fixed tailplane, enlarged ailerons but since the superior Sopwith Tabloid and Bristol Scout were available the army delined any order. The "Sissit" was abandoned. For the next model however, the Dutch designer simply "borrowed" the Aircraft Factory B.E.2c design already produced under licence and modified it in some points; it was a success, produced to around 500 as the F.K.3. The next F.K.4 was a paper project, just like the F.K.2, but the F.K.5 and 6 were built, as experimental triplanes to serve as escort fighters, answering to a 1916 War office specification. The FK5 never flew, modified with the gunner's nacelles slung under the middle wing, shorter and a deeper fuselage, and conventional tailskid. Four were ordered in April but only one built, showing poor performances, whereas synchronized MGs were now available, and the whole program ended.

AW FK8 cockpit closeup

The next F.K.8 was a simple "copy-paste, repeat" of the F.K.3. It was a conventional, sturdy, all-purpose two-seater biplane powered by a Beardmore 120 hp 6-cylinder inline piston engine, 160 hp (112 kW). About 1,650 were manufactured, which served long after the war for the company Qantas, the Kingdom of Hejaz and Paraguay. The previous F.K.7 has been planned as a replacement for both the Royal Aircraft Factory B.E.2c and the Armstrong Whitworth F.K.3. introducing basic dual controls for the pilot and observer. It flew in May 1916, but for marketing purposes when pitted against the Royal Aircraft Factory R.E.8 it was renamed F.K.8. and ordered in quantities. The next F.K.9 and F.K.10 were interesting escort fighter designed as quadruplanes, the only ones in service with the RFC (Photo).

AW FK8 cockpit closeup

This oddball only saw one prototype for the RFC (with a 110 hp (80 kW) Clerget 9Z engine) and eight of pre-production test F.K.10, featuring a revised fuselage and tail, with a 130 hp (100 kW) Clerget 9B/Le Rhône 9J engines. The initial order of 50 was dropped after testing the first batch (see later for details). The next wartime model of the company was the Armadillo, this time designed by Koolhoven successor, Fred Murphy. It was a private-venture project, centered around the promising Bentley BR2 rotary engine. It was more to test the skills of the new design team rather than a response to an official requirement. It was a two-bay biplane with a square section fuselage, with two .303 in (7.7 mm) Vickers machine guns fitted on the cowl and synchronized, in January 1918. It made its first flight in April 1918 and compared badly to the Sopwith Snipe because of its poor view from the cockpit. It led to the more advance Ara, postwar (first flight 1919) of which two prototypes were built and tested but dropped because grave issues with the new ABC Dragonfly engine.

AW Models:

  • Armstrong Whitworth F.K.1 (1914)"Sissit" (1)
  • Armstrong Whitworth F.K.2 (1915) (8)
  • Armstrong Whitworth F.K.3 (1915) (500)
  • Armstrong Whitworth F.K.6 (1916) (2)
  • Armstrong Whitworth F.K.8 (1916) "Big Ack" (1,650)
  • Armstrong Whitworth F.K.9/10 (1916-17) "Quadriplane" (9)
  • Armstrong Whitworth Armadillo (1)
  • Airship R25
  • Airship R29
  • Airship R33

Armstrong Whitworth F.K.3 (1915)


This two-seat general-purpose biplane was designed by Dutch designer Frederick Koolhoven. It was a near-copy of the Royal Aircraft Factory B.E.2c, already built by AW for the Royal Flying Corps. Th first prototype was flown in 1915 by Norman Spratt, powered by a 70 hp (52 kW) air-cooled Renault 70 hp V-8. It was made simpler than its inspiration plane, by eliminating welded joints and complex metal components in the structure. To test the concept, seven aircraft were built, retrospectively called FK.2 sometimes. It was rejected by the RFC as offering little advantage over the BE2C; therefore Armstrong Whitworth worked on an improved version, with a new fin and rudder, a more effective field of fire for the observer, straight leading edge, no horn balance, and a 90 hp (67 kW) RAF 1a engine, derived from the Renault engine. The new FK.3 flown at Upavon in May 1916 and this time estimated superior to the BE2C on all accounts but the loading capacity despite its formula was already obsolescent. 150 were ordered by the RFC to AW, while 350 more were ordered to Hewlett & Blondeau Limited at Luton. The arly and later version could be distinguished by their rams' horns forward stubs, which replaced their initial twin high exhaust pipes exiting above the upper wing. Later during production, RAF engines were in short supply, therefore 12 planes were tested with the new heavier 120 hp (90 kW) six-cylinder inline water cooled Beardmore 120 hp and span was increased by 2 ft (610 mm) to compensate. They were converted back with RAF engine as soon as they were available. Oddly these planes were never deployed operationally in France (FK.8 were preferred), but kept mostly for training and reserve units in UK, with the No. 43, 47, 53, 55 and 63 Squadron RFC. Only those of the 47 Squadron at Salonika operated this model in action, which was obsolete by early 1918. The bulgarians captured one, and the Australian Flying Corps No. 3 Squadron AFC also used this model for training.


Dimensions: Length: 29 ft (8.84 m), Wingspan: 40 ft (12.19 m), Height: 11 ft 11 in (3.63 m)
Empty weight: 1,386 lb (629 kg), Max. takeoff weight: 2,056 lb (983 kg)
Engine: 1 × RAF 1A inline piston engine, 90 hp (67 kW)
Performance: Top speed: 77 kn (89 mph, 143 km/h) at sea level
Service ceiling: 12,000 ft (3,660 m), Endurance: 3hr
Armament: 0.303 in (7.7 mm) Lewis Gun, rear observer cockpit/up to 112 lb (51 kg) bombs, single seater version

Armstrong Whitworth F.K.8 (1916)

AW FK8 early production

This British two-seat general-purpose biplane served alongside the R.E.8 until the end of the war. 694 F.K.8s have been delivered, 1650 total, counting exports and postwar production. It was designed by Frederick Koolhoven to replace the Royal Aircraft Factory B.E.2c and FK.3. It was more powerful (160 hp (110 kW) Beardmore water-cooled engine), larger, sturdier, had oleo-pneumatic landing gear, a scarff-mounted MG Lewis, and the rudder had a rudder featuring a long, pointed horn-balance. It was also serial-fitted with dual controls in case the pilot was injured, for the observer to take control. Outside the Armstrong Whitworth synchronization mechanism, not reliable, the plane used at an early stage the Arsiad interrupter gear and Constantinescu gear. Bt the plane had many teething problems like a weak oleo undercarriage and blocked radiators.

AW FK8 late production

The tail was modified also and the wings, gunner's seat and exhaust system were revised, nose cowling and radiators too lately so there were three distinct production versions over time. Nicknamed "Big Ack") it proved effective and dependable, was liked for its crew and trusted upon to led reconnaissance missions as well as strafing and ground attacks or night bombing. The prototype flew in late 1916 and it arrived first at 35 Squadron RFC, in January 1917. It served well in France, Macedonia, Palestine, for home defence. It was able to carry six 40 lb (20 kg) phosphorus smoke bombs, four 65 lb (29 kg) bombs or two 112 lb (51 kg) bombs on underwing racks and the pilot was given a forward-firing .303 in Vickers machine gun. By the early 1920s these planes had been all discarded. Some served for much more years afterwards with QANTAS in Australia, the small Kingdom of Hejaz AF or Paraguay.

AW FK8 final Prodution


Dimensions: Length: 31.5 ft (9.58 m), Wingspan: 43.6 ft (13.26 m), Height: 10 ft 11 in (3.33 m)
Empty weight: 1,916 lb (869 kg), Max. takeoff weight: 2,811 lb (1275 kg)
Engine: Beardmore 6-cyl engine, 160 hp (112 kW)
Performance: Top speed: 83 kn (95 mph, 153 km/h) at sea level
Service ceiling: 13,000 ft (3,960 m), Endurance: 3hr
Armament: 1x .303 Vickers FF, 1x 0.303 in (7.7 mm) Lewis Gun (observer), up to 224 lb bombs

Read More:

Armstrong Whitworth on wikipedia
On britishaviation-ptp.com
AW on historyofwar.org