The Vickers F.B.25 was a British two-seat night fighter

prototype A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototyp ...

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

designed to attack enemy

airship An airship or dirigible balloon is a type of aerostat or lighter-than-air aircraft that can navigate through the air under its own power. Aerostats gain their lift from a lifting gas that is less dense than the surrounding air. In early ...

s. Completed in 1917, it failed in its official flight tests that year and no order for production resulted.

Design

In 1916,

Vickers Limited Vickers Limited was a British engineering conglomerate. The business began in Sheffield in 1828 as a steel foundry and became known for its church bells, going on to make shafts and propellers for ships, armour plate and then artillery. Entir ...

designed a two-seat

pusher configuration In an aircraft with a pusher configuration (as opposed to a tractor configuration), the propeller(s) are mounted behind their respective engine(s). Since a pusher propeller is mounted behind the engine, the drive shaft is in compression in nor ...

biplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While ...

fighter, the F.B.23, to replace its obsolete

Vickers F.B.5 The Vickers F.B.5 (Fighting Biplane 5) (known as the "Gunbus") was a British two-seat pusher military biplane of the First World War. Armed with a single .303 in (7.7 mm) Lewis gun operated by the observer in the front of the ...

and F.B.9 "Gunbuses". A number of versions of the FB.23 were planned depending on the engine used, with possible powerplants including a 150 hp (119 kW) Salmson water-cooled

radial engine The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ca ...

, a 150 hp Hart air-cooled radial engine and a 200 hp (149 kW)

Hispano-Suiza 8 The Hispano-Suiza 8 was a water-cooled V8 SOHC aero engine introduced by Hispano-Suiza in 1914, and was the most commonly used liquid-cooled engine in the aircraft of the Entente Powers during the First World War. The original Hispano-Suiza ...

V-8 engine A V8 engine is an eight-cylinder (engine), cylinder piston engine in which two banks of four cylinders share a common crankshaft and are arranged in a V engine, V configuration. The first V8 engine was produced by the French Antoinette_(manuf ...

. The pusher configuration was obsolete however, compared to prospective tractor aircraft such as the

Bristol F.2 Fighter The Bristol F.2 Fighter is a British First World War two-seat biplane fighter and reconnaissance aircraft developed by Frank Barnwell at the Bristol Aeroplane Company. It is often simply called the Bristol Fighter, ''"Brisfit"'' or ''"Biff"'' ...

, which was both faster than the estimated performance of the F.B.23 and carried a heavier armament, so Vickers abandoned the F.B.23 without an example being built.Bruce 1969, pp. 123-4. Vickers reworked the F.B.23 to form the basis of a two-seat

night-fighter A night fighter (also known as all-weather fighter or all-weather interceptor for a period of time after the Second World War) is a fighter aircraft adapted for use at night or in other times of bad visibility. Night fighters began to be used i ...

, the F.B.25, to compete with the

Royal Aircraft Factory N.E.1 The Royal Aircraft Factory N.E.1 was a prototype British Night fighter of the First World War. A single-engined pusher biplane, it was a development of the Royal Aircraft Factory's earlier F.E.9 fighter, but was not successful, only six being ...

to meet a British requirement for a night fighter capable of attacking German

s. The F.B.25 used an identical tail and tail boom assembly to the F.B.23, but had modified wings and a completely new fuselage

nacelle A nacelle ( ) is a "streamlined body, sized according to what it contains", such as an engine, fuel, or equipment on an aircraft. When attached by a pylon entirely outside the airframe, it is sometimes called a pod, in which case it is attached ...

. The F.B.25 was a two-bay biplane with unstaggered

wing A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expres ...

s of equal

span Span may refer to: Science, technology and engineering * Span (unit), the width of a human hand * Span (engineering), a section between two intermediate supports * Wingspan, the distance between the wingtips of a bird or aircraft * Sorbitan es ...

. Its nacelle was mounted between the wings, was unusually wide for an aircraft of its type in its day, and accommodated the two-man crew, a pilot and a gunner, in staggered side-by-side seats, with the gunners seat ahead and to

starboard Port and starboard are nautical terms for watercraft and aircraft, referring respectively to the left and right sides of the vessel, when aboard and facing the bow (front). Vessels with bilateral symmetry have left and right halves which are ...

of the pilots. The gunner was armed with a single 1.59-inch Breech-Loading Vickers Q.F. Gun, Mk II, popularly known as the "Vickers-Crayford rocket gun," which despite its popular name was a lightweight 40 mm single-shot gun that fired shells and had no

rocket A rocket (from it, rocchetto, , bobbin/spool) is a vehicle that uses jet propulsion to accelerate without using the surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely fr ...

-launching capability.Williams and Gustin 2003, pp. 85, 93. Its tailbooms converged in elevation to meet at the rear spar of the

tailplane A tailplane, also known as a horizontal stabiliser, is a small lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyroplane ...

. It had a single

propeller A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon ...

, mounted in a

. The aircraft had an oleo-pneumatic

undercarriage Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include: *The landing gear of an aircraft. *The ch ...

, an unusual feature for the time.Mason 1992, pp. 107–8. Plans called for the F.B.25 to mount a small

searchlight A searchlight (or spotlight) is an apparatus that combines an extremely bright source (traditionally a carbon arc lamp) with a mirrored parabolic reflector to project a powerful beam of light of approximately parallel rays in a particular direc ...

in the nacelles nose, have a nosewheel to reduce the chance of the aircraft turning over during night landings, and use the same 200-

horsepower Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. There are many different standards and types of horsepower. Two common definitions used today are the ...

(149-

kilowatt The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James Wa ...

) Hispano-Suiza 8 planned for the F.B.23. As design and construction progressed, Vickers made changes; the searchlight and nosewheel were deleted, and as the 200-horsepower engine was unavailable, Vickers substituted a 150-horsepower (112-kilowatt) Hispano-Suiza.

Operational history

Vickers completed the F.B.25 prototype in the early spring of 1917. Company flight testing revealed poor characteristics. The prototype was sent to Martlesham Heath in June–July 1917 for official testing, and official reports declared that the F.B.25 had poor control characteristics, being "very dangerous" with the engine off, and "almost unmanageable in a wind over 20 miles per hour" (32 km/h). The aircraft was condemned as being completely unsuited for use as a night fighter. No further aircraft were built, and the lone F.B.25 later crashed at Martlesham Heath.''Flight'' of 12 June 1919
reports the aircraft crashed on the way to Martlesham Heath in May 1917

Variants

;F.B.23 :Proposed two-seat fighter. Three versions planned with different powerplants. All unbuilt. ;;F.B.23: ::150 hp (119 kW) Salmson water-cooled

;;F.B.23A ::150 hp Hart air-cooled radial engine. ;;F.B.23B ::200 hp (149 kW)

engine. ;F.B.25 :Two-seat night-fighter based on F.B.23 but with side-by-side seating. One built, powered by 150 hp Hispano-Suiza engine.Bruce 1969, pp. 124–125.

Operators

; *

Royal Flying Corps "Through Adversity to the Stars" , colors = , colours_label = , march = , mascot = , anniversaries = , decorations ...

Specifications

Notes

References

* Bruce, J. M. ''War Planes of the First World War:Volume Three Fighters''. London:Macdonald, 1969. . *Mason, Francis K. ''The British Fighter since 1912''. Annapolis, Maryland, USA:Naval Institute Press, 1992. . *Williams, Anthony G. and Gustin, Emmanuel. ''Flying Guns: World War I and its Aftermath 1914-32''. Ramsbury, UK:Airlife, 2003. . {{wwi-air 1910s British fighter aircraft Single-engined pusher aircraft Aircraft first flown in 1917