Derived from the abortive F.B.23 design intended as a successor to the F.B.9, the F.B.25 two-seat night fighter was conceived to fulfil the same requirement as the Royal Aircraft Factory’s N.E.1. Completed in the early spring of 1917, the F.B.25 carried its two crew members in staggered side-by-side seats, the gunner being positioned ahead and to starboard. Like the N.E.1, the F.B.25 was intended to carry the Vickers-built Crayford rocket gun with which it was supposed to attack hostile airships, and a small searchlight was originally to have been mounted in the extreme nose of the nacelle. The intention was to power the F.B.25 with the 200hp Hispano-Suiza eight-cylinder water-cooled engine, and in order to minimise the risk of the aircraft turning over during a nocturnal landing, it was proposed to provide a nosewheel. In the event, non-availability of a 200hp unit dictated installation of a 150hp Hispano-Suiza, and neither searchlight nor nosewheel was fitted. A two-bay unstaggered equi-span biplane with tailbooms converging in elevation to meet at the rear spar of the tailplane, the F.B.25 carried its unusually wide nacelle at mid wing-gap. As well as the Crayford rocket gun, an interesting feature was the oleo-pneumatic undercarriage. Flight testing revealed poor characteristics, and when sent to Martlesham Heath in May 1917 (where it was eventually to crash), the official reports were singularly unflattering, dismissing the F.B.25 as wholly unsuited for night fighting.

Max take-off weight: 1113 kg / 2454 lb
Empty weight: 729 kg / 1607 lb
Wingspan: 12.65 m / 42 ft 6 in
Length: 8.56 m / 28 ft 1 in
Height: 3.30 m / 11 ft 10 in
Wing area: 46.45 sq.m / 499.98 sq ft
Max. speed: 138 km/h / 86 mph
Ceiling: 3355 m / 11000 ft

A two-seat fighter-reconnaissance aircraft, the F.B.24 was yet another Vickers aircraft originally designed for the ill-fated and Vickers-sponsored Hart radial engine. The prototype was completed in December 1916, but unavailability of the Hart engine resulted in its modification to accept the 150hp Hispano-Suiza water-cooled engine as the F.B.24A, and the second airframe, the F.B.24B, being similarly powered. An unequal-span two-bay biplane, the F.B.24 had an armament of one fixed synchronised Vickers gun and one Lewis on a Scarff ring mounting. Both F.B.24A and 24B were re-engined with the 200hp Hispano-Suiza with which they were redesignated as F.B.24Ds. Similar in general configuration was the F.B.24C, which was powered by a 275hp Lorraine-Dietrich 8Bd water-cooled eight-cylinder Vee-type engine and armed with two synchronised Vickers guns, provision being made for emergency dual control in the gunner’s cockpit. The F.B.24C and D both possessed good performance, but the limited view offered from the pilot’s cockpit was considered unacceptable. Consequently, the Vickers team revised the basic design by lowering the upper wing so that it was attached directly to the upper longerons, the front cockpit being situated between the wing spars. With this change, the aircraft was de signated F.B.24E and power was provided by a 200hp Hispano-Suiza. This same configuration was adopted for yet a further version of the design, the F.B.24G, which was a larger aircraft than its predecessors, with two-bay wings of equal span and chord and a 375hp Lorraine-Dietrich 12-cylinder Vee-type engine. The F.B.24G was built in France by the Darracq concern, but it did not fly until 26 May 1919, and its performance and fate have gone unrecorded.

F.B.24D
Empty weight: 739 kg / 1629 lb
Wingspan: 10.82 m / 36 ft 6 in
Length: 7.92 m / 26 ft 0 in
Wing area: 31.59 sq.m / 340.03 sq ft
Max. speed: 190 km/h / 118 mph

Conceived, like the F.B.12, to utilise the 150hp Hart engine, the F.B.16 was designed by Rex K Pierson. Completed and flown in the summer of 1916, it was a single-bay staggered biplane with a fuselage faired out fully to an elliptical cross section, the Hart engine being partly cowled, and armament consisting of a single centrally-mounted synchronised 7.7mm Vickers gun. During the course of testing, the part-cowling was removed from the engine to improve cooling, the decking aft of the cockpit was cut down and new vertical tail surfaces were fitted. With the ending of Hart engine development, the basic F.B.16 underwent very considerable redesign, reappearing as the F.B.16A with a 150hp Hispano-Suiza water-cooled Vee-eight engine. This aircraft was destroyed in a crash on 20 December 1916, but a second identical aircraft was completed in the following month. The F.B.16A had flat fuselage sides and the single synchronised Vickers gun was supplemented by a Lewis mounted above the centre section.
After receiving favourable reports during Martlesham Heath trials, it was re-engined with a 200hp Hispano-Suiza engine as the F.B.16D, a wider-chord wing being fitted, with both gap and stagger increased, and a larger vertical tail fitted. The synchronised Vickers gun was replaced by a Lewis firing through the hollow propeller shaft. Because large contracts had been placed for the contemporary S.E.5a, particularly with Vickers, and because Martlesham Heath evaluation contained numerous design criticisms of which rectification would have been time consuming, the F.B.16D was not ordered into production.
Nonetheless, work on a further development, the F.B.16E, continued, this having a 275hp Lorraine-Dietrich 8Bd eight-cylinder Vee-type water-cooled engine and two 7.7mm synchronised Vickers guns totally enclosed in elongated blisters between the cylinder block fairings. The F.B.16E was tested at Villacoublay by the French authorities, encouraged by the manufacturer’s performance claims, including a speed of 220km/h at 3050m and the ability to climb to that altitude within 7.85 min. During Villacoublay trials, the F.B.16E allegedly returned performance figures unsurpassed by any of its contemporaries, but no production order was placed, and on 29 July 1918, the prototype crashed after its propeller disintegrated.

F.B.16D
Max take-off weight: 850 kg / 1874 lb
Empty weight: 624 kg / 1376 lb
Wingspan: 7.62 m / 25 ft 0 in
Length: 5.94 m / 20 ft 6 in
Height: 2.67 m / 9 ft 9 in
Wing area: 19.23 sq.m / 206.99 sq ft
Max. speed: 217 km/h / 135 mph
Ceiling: 5640 m / 18500 ft

Tractor-engined biplane best suited for reconnaissance duties. Engines ranged on the small number of production aircraft from an 89kW Beardmore to a 186kW Rolls-Royce Eagle.

Vickers FB.14 Article

Max. speed: 180 km/h / 112 mph

Designed by Howard Flanders as an airship destroyer, for which purpose it had an elevated gunner’s station, or “fighting top”, mounted on the centre section of the upper wing, the F.B.11 flew in late November 1916. Carrying a crew of three, including two gunners each provided with a 7.7mm Lewis gun, the F.B.11 was powered by a 250hp Rolls-Royce Mk III 12-cylinder water-cooled engine – later to be named Eagle. The F.B.11 proved to be deficient in lateral control and the first prototype eventually crashed and was written off, a second example never being completed as, in the meantime, it had been realised that the entire concept of the large airship destroyer was fundamentally unsound.

Max take-off weight: 2238 kg / 4934 lb
Empty weight: 1515 kg / 3340 lb
Wingspan: 15.54 m / 51 ft 0 in
Length: 13.10 m / 43 ft 0 in
Height: 4.16 m / 14 ft 8 in
Wing area: 78.50 sq.m / 844.97 sq ft
Max. speed: 154 km/h / 96 mph
Ceiling: 3355 m / 11000 ft

Early in 1915, Rex K Pierson was tasked with the redesign of the so-called Barnwell Bullet, an unarmed single-seat biplane designed as a private venture by Vickers’ then chief test pilot, Harold Barnwell. Assigned the designation E.S. (Experimental Scout) 1 and completed in August 1915, the redesigned aircraft was powered by a 100hp Gnome Monosoupape rotary and carried no armament. An equi-span single-bay unstaggered biplane, the E.S.1 was aerodynamically clean and possessed an excellent performance, but view for the pilot was extremely poor. An improved version was then developed, powered by the 110hp Clerget nine-cylinder rotary engine. This was assigned the official designation E.S.1 Mk II, although it was known to Vickers as the E.S.2. Two E.S.1 Mk IIs were built, one of these being fitted with a 7.7mm Vickers machine gun with Vickers-Challenger synchronising gear and sent to France in the summer of 1916 for operational trials with No 11 Sqn, RFC. The other E.S.1 Mk II was eventually similarly armed and tested with a 110hp Le Rhone rotary, while the original E.S.1, too, was fitted with the gun and synchronization gear, and was at one time included on the strength of an RFC Home Defence squadron (No 50). The official evaluation of the E.S.1 in both versions pronounced the aircraft tiring to fly and difficult to land, and no production was ordered. The E.S.1 did, however, serve as a basis for the design of the later F.B.19.

E.S.1 Mk II
Max take-off weight: 681 kg / 1501 lb
Empty weight: 445 kg / 981 lb
Wingspan: 7.43 m / 24 ft 5 in
Length: 6.17 m / 20 ft 3 in
Height: 2.34 m / 8 ft 8 in
Wing area: 19.97 sq.m / 214.96 sq ft
Max. speed: 180 km/h / 112 mph