Just eight out of the 50 Armstrong Whitworth F.K.10 quadruplanes ordered were completed for service with the Royal Flying Corps and Royal Naval Air Service.
Authored By: Staff Writer | Last Edited:
Credit: Image from the Public Domain.
The Armstrong Whitworth F.K.10 fighter was the full production-minded realization of the earlier F.K.9 prototype (detailed elsewhere on this site). The types were formed around a single-engine, twin-seat "quadruplane" platform and the F.K.10 model became one of the few quadruplane designs to see formal adoption by a major air service during World War 1 (1914-1918). However, the series managed only eight completed forms before being given up for good. The F.K.9 prototype first-flew in late-1916 and paved the way for the modified (and slightly improved) F.K.10 that followed in 1917.
At this point in the war the biplane was entrenched as the primary fighter standard though a few companies were able to sell the various air services on a monoplane fighter design. The triplane's appearance in 1917 vaulted multi-winged gunnery platforms to the forefront but this dominance was short-lived and the biplane remained the standard. Aeronautical engineers saw the value in adding more wings to an aircraft but this ultimately came at a steep price - drag. Multiple wings provided additional lift and better controlling at the expense of additional air resistance which did not bode well as a strong quality for a fighter to have - speed was still the call of the day as it were. As such, there were many failed experiments in the realm of more-than-three winged aircraft during the war years - the F.K.10 more or less being an exception.
Developed for the reconnaissance-fighter role, the F.K.10 carried a tandem, two-seat crew configuration in which the pilot managed a sole, synchronized and fixed .303 Vickers machine gun at front and the rear gunner / observer was given management of a .303 Lewis Gun set atop a trainable mounting at rear. The fuselage of the aircraft was well-rounded at the front and tapered to the rear with slab-sides running the length. The tail unit was of a traditional single-finned arrangement with elevated horizontal planes positioned along the sides. The engine was held in a compartment at the nose of the aircraft and drove a two-bladed wooden propeller in the usual way. The undercarriage was wheeled and of a "tail-dragger" configuration - the main legs being wheeled for ground running.
The quadruplane wing arrangement appropriately featured four planes set parallel to one another. A thick supporting structure (called an "interplane strut") was run through all four planes for the needed strength. The stacked wings were noticeably cranked forwards from the bottom-up when viewing the aircraft's side profile. The pilot's cockpit was positioned aft of the engine but under the top-most wing plane and behind the second plane. The third plane was positioned midway along the sides of the fuselage with the fourth plane held low and away from the belly of the aircraft.
Power for the series was to come from a Clerget 9B rotary engine of 130 horsepower, giving it more output than the original prototype's Clerget 9Z rotary of 110 horsepower.
Design of the F.K.10 was attributed to Dutchmen Frederick Koolhoven dating back to 1916's F.K.9 prototype. His surname would go on to drive some of the aircraft designs emerging from the Netherlands during the lead-up to World War 2 (1939-1945).
The F.K.9 impressed enough that a production order for 50 aircraft was signed by the Royal Flying Corps (RFC). However the noticeable issue of drag soon limited the need for the quad-winged F.K.10 and only eight were completed in all - the biplane still being the favored wing arrangement for fighters and bombers. Five examples were finished before the formal cancellation of the contract came down though three more followed for the Royal Naval Air Service and saw some testing before the end.
[ 8 Units ] : Armstrong Whitworth - United Kingdom
- Reconnaissance (RECCE)
22.24 ft (6.78 m)
27.82 ft (8.48 m)
11.48 ft (3.5 m)
(Showcased structural dimension values pertain to the Armstrong Whitworth F.K.10 production model)
1,246 lb (565 kg)
2,028 lb (920 kg)
(Showcased weight values pertain to the Armstrong Whitworth F.K.10 production model)
1 x Clerget 9B rotary engine developing 130 horsepower and driving two-bladed wooden propeller at nose.
(Showcased powerplant information pertains to the Armstrong Whitworth F.K.10 production model)
84 mph (135 kph; 73 kts)
10,007 feet (3,050 m; 1.9 miles)
211 miles (340 km; 184 nm)
455 ft/min (139 m/min)
(Showcased performance values pertain to the Armstrong Whitworth F.K.10 production model; Compare this aircraft entry against any other in our database)
1 x .303 Vickers machine gun in fixed, forward-firing mounting over the nose, synchronized to fire through the spinning propeller blades.
1 x .303 Lewis Gun on trainable mounting in rear cockpit.
(Showcased armament details pertain to the Armstrong Whitworth F.K.10 production model)
F.K.10 - Base Series Designation; eight examples delivered out of 50 ordered.
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