C.Andrews Vickers Aircraft since 1908 (Putnam)
In 1916 a single-seat fighter to take the Vickers-sponsored Hart radial engine was designed by R. K. Pierson. This was the F.B.16 tractor and was known as the Hart Scout. The Hart engine proved as disappointing as previous power units (such as the Boucier) sponsored by Vickers. After considerable redesign the type reappeared as the F.B.16A with a 150 hp Hispano Suiza, a French-designed water-cooled engine then coming into favour with the British air authorities. Later the more powerful 200 hp Hispano Suiza was substituted, and in this form the aeroplane became the F.B.16D. It earned the unqualified praise of Maj J. B. McCudden, the British air ace, of 56 Squadron, whose book on five years in the RFC remains the classic on air fighting and the technology thereof in the first world war. In this book he describes vividly, as follows, his experiences in flying the all-red F.B.16D at Joyce Green, where he was a constant visitor when on leave from France.
'On 22 June, 1917, I flew the little Vickers tractor, the F.B.16D, which was now fitted with a 200 hp Wolseley-Hispano. I climbed to 10,000 ft in eight minutes and at that height the machine did 136 mph. Whilst flying that machine I got some idea of the speed of future machines, for at 10,000 ft it was 30 mph faster at least than anything I had yet flown. Harold Barnwell liked this little machine, although he said it cost him a new pair of trousers every time he flew it, as it always smothered his legs with oil. It has a very deep fuselage rather out of proportion to the size of the machine and Barnwell always alluded to it as "Pot-Belly".'
McCudden was keen to take the F.B.16D with him to his Squadron in France, but it was not the policy to allow pilots, however distinguished, to have, at the Front, personal aircraft which differed from standard equipment. He therefore left the F.B.16D at Joyce Green when he returned to France, where he was killed in an accident to his S.E.5a before reaching his base.
The F.B.16D never went into production because large contracts had been placed for the contemporary S.E.5a, particularly with Vickers at Crayford and Weybridge, and because the engine in the Vickers fighter was inaccessible for servicing and maintenance in the field. But it embodied an unusual feature for a British aeroplane. A Lewis gun was installed between the vee formed by the cylinder blocks and fired through the hollow propeller-shaft which rotated through gearing above the engine crankshaft. How the ammunition drums were changed or whether a belt feed was substituted, or, indeed, how the empty cartridge cases were collected or jettisoned, remains unexplained.
A derivative of the type, the F.B.16E, was made, under licence by S. A. Darracq in France, with larger two-bay wings to cater for the extra weight of the 275 hp Lorraine-Dietrich engine, but it did not go into large-scale production there.
F.B.16D - One 200 hp Hispano Suiza. Span 25 ft, upper, and 22 ft 4 in, lower; length 19 ft 6 in; height 8 ft 9 in; wing area 207 sq ft. Empty weight 1,376 lb; gross weight 1,875lb. Max speed 135 mph at 10,000 ft; climb to 10,000 ft - 10 1/2 min; service ceiling 18,500 ft; absolute ceiling 21.000 ft; endurance 2 1/4 hr. Armament - two Lewis guns.
P.Lewis The British Fighter since 1912 (Putnam)
1916 was the year in which Vickers produced another single-seat fighter, the F.B.16, which was to undergo considerable development as a basic design. The F.B.16 was a neat and workmanlike single-bay biplane and was able to be fitted with the engine scheduled for it, the 150 h.p. Hart radial, which had had to be abandoned as the unit for the Vickers F.B.12. Modifications were made in the F.B.16, which included removal of the cowling over the engine, the rounding of the previously humped fin outline, the replacement of the two-blade propeller by a four-blader, and the fitting of a considerably smaller headrest for the pilot.
Vickers decided to put in hand an extensive redesign of the F.B.16 which came into the open in December, 1916, as the F.B.16A. The new fighter was of quite pugnacious aspect with sharply-staggered wings mated to a straight-sided fuselage, in the nose of which was mounted the 150 h.p. Hispano-Suiza engine. The top and bottom of the fuselage were rounded and the fin and rudder outline followed that of the modified F.B.16. The undercarriage was set well forward and the single Vickers gun, as fitted also to the F.B.16, was mounted on the front decking. In addition, the F.B.16A carried a Lewis gun on the upper centre-section on a sliding mounting.
Test flights on 20th December, 1916, carried out by Capt. Simpson, resulted in a fatal crash but Vickers constructed another F.B.16A, the trials of which R. H. Barnwell conducted. Despite the lively performance which the F.B.16A exhibited it was not to receive a production order.
Nevertheless, Vickers continued to expend time and money in developing the design still further so that, by June of 1917, F.B.16A A8963 had been transformed into the F.B.16D. As well as minor modifications to the airframe, engine power was stepped up by installing the 200 h.p. Hispano-Suiza, the armament comprising a Lewis gun firing through the propeller shaft and a second gun of the same type on the upper centre-section. The F.B.16D would have stood a good chance of being adopted for Service use as its performance was excellent for its time but engine accessibility was considered to be below the standard necessary for field maintenance.
Two other versions of the F.B.16 were to appear - the generally-larger F.B.16E with two-bay wings, 275 h.p. Lorraine-Dietrich engine and two fuselage-mounted Vickers guns, and the F.B.16H which was similar to the F.B.16E but had even greater power from a 300 h.p. Hispano-Suiza engine which brought its speed at ground level to 147 m.p.h.
F.Mason The British Fighter since 1912 (Putnam)
The Vickers F.B.16 was designed by Rex Pierson as a private venture in the first place principally to demonstrate the Vickers-sponsored 150hp Hart radial engine which, it will be recalled, had not been ready in time for the F.B.12. The new engine gave its name to Pierson’s design and the Hart Scout originally appeared as a single-bay biplane, its fairly heavily staggered wings being of unequal span and chord with rounded tips. The engine was neatly cowled, but evidently suffered from overheating as the cowling was soon removed. The fin and rudder also underwent alteration, the fin being reduced in area and the rudder shape changed to present a smoothly curved upper line, while the fuselage aft of the cockpit was reduced in depth in favour of a small headrest fairing.
The Hart engine gave almost continuous trouble and it was removed from the F.B.16 which, early in the autumn of 1916, was redesigned and re-emerged as the F.B.16A in December, now powered by a 150hp Hispano-Suiza driving a two-blade propeller. This installation, which featured a frontal radiator, allowed a narrower fuselage which was now flat sided with curved top and bottom fairings. The unequal-span wings were retained but were given raked tips. Armament comprised a synchronized Vickers gun and a Lewis gun on a sliding mounting above the upper wing centresection.
After the first F.B.16A was destroyed in a fatal accident, a second machine, A8963, was built and sent to Martlesham for Service trials during which it returned a top speed of 120 mph at 6,500 feet; it was not, however, recommended for production owing, it is believed, to an official preference for the S.E.5. Nevertheless, its development continued and A8963 reappeared as the F.B.16D in the summer of 1917 with a 200hp Hispano-Suiza, returning to Martlesham in July where its speed at 10,000 feet was recorded as 135 mph. The F.B.16D became a favourite mount of Capt J T B McCudden MC who used to visit Joyce Green when on leave from France.
Once more the F.B.16 underwent extensive redesign, much larger two-bay wings being fitted; the fuselage was also lengthened to allow the installation of a 275hp Lorraine-Dietrich vee-eight liquid-cooled engine, also with a frontal radiator. Although this variant, the F.B.16E, had a top speed of about 144 mph at sea level, this performance was bettered by the final variant, the F.B. 16H, powered by a 300hp Hispano-Suiza, which had a maximum speed of 147 mph and could reach 10,000ft in 7 minutes 50 seconds.
These were some of the highest speeds yet confirmed by a fully-armed fighter at that time (mid-1918), but they were achieved using foreign engines, and the Service policy was moving slowly in favour of British designs; in any case, fighters of comparable performance, such as the Sopwith Snipe and Dolphin, were already approaching production status, and the Vickers work, perhaps unjustly, remained purely experimental.
Type: Single-engine, single-seat, single- and two-bay biplane scout.
Manufacturer: Vickers Ltd (Aviation Department), Knightsbridge, London.
Powerplant: F.B.16. One 150hp Hart radial engine. F.B.16A. 150hp Hispano-Suiza. F.B.16D. 200hp Hispano-Suiza. F.B.16E. 275hp Lorraine-Dietrich. F.B.16H. 300hp Hispano-Suiza.
Dimensions: F.B.16A. Span, 25ft 0in; length, 19ft 0in; height, 7ft 10in; wing area, 199 sq ft. F.B.16D. Span, 25ft 0in; length, 19ft 6in; wing area, 207 sq ft. F.B.16E. Span, 31ft 0in; length, 21ft 0in; wing area, 272 sq ft.
Weights: F.B.16D. Tare, 1,376lb; all-up, 1,875lb. F.B.16E. Tare, 1,495lb; all-up, 2,200lb.
Performance: F.B.16D. Max speed, 140 mph at sea level; climb to 10,000ft, 10 min 25 sec; service ceiling, 18,500ft. F.B.16E. Max speed, 144 mph at sea level; climb to 10,000ft, 7 min 50 sec; service ceiling, 24,000ft.
Armament: F.B.16D. One 0.303in Lewis gun mounted between cylinder banks of engine and firing through propeller shaft, and a Lewis gun on sliding mounting above upper wing centre section. F.B.16E. Two synchronized Vickers guns in cowling above engine and a Lewis gun on sliding mounting above upper wing.
Prototypes: One prototype served as F.B.16 and F.B.16A; a second F.B.16A, A8963, also served as prototype F.B.16D, E and H.
W.Green, G.Swanborough The Complete Book of Fighters
VICKERS F.B.16 UK
Conceived, like the F.B.12, to utilise the 150 hp 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 0.303-in (7,7-mm) 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 150 hp 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 200 hp 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 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. The following data relate to the F.B.16D.
Max speed, 135 mph (217 km/h) at 10,000 ft (3050 m), 126 mph (203 km/h) at 15,000 ft (4 570 m).
Time to 10,000 ft (3 050 m), 10.45 min.
Service ceiling, 18,500 ft (5 640 m).
Endurance, 2.25 hrs.
Empty weight, 1,376 lb (624 kg).
Loaded weight, 1,875 lb (850 kg).
Span, 25 ft 0 in (7,62 m).
Length, 19 ft 6 in (5,94 m).
Height, 8 ft 9 in (2,67 m).
Wing area, 207 sqft (19,23 m2).
J.Bruce British Aeroplanes 1914-1918 (Putnam)
THE Vickers F.B.16 was a single-seat fighter which was designed in 1916. It was a tractor biplane designed to have the 150 h.p. Hart radial engine which had failed to materialise for the earlier Vickers F.B.12.
In the case of the F.B.16, however, an example of the Hart engine was available, and the machine was completed and flown. In its original conception the F.B.16 had its fuselage faired cut fully to an elliptical cross-section and was quite a clean aeroplane. The pilot sat fairly high and, since the upper wing was close to the top of the fuselage, had a fairly good view in most upward directions; but the bulky engine, the faired sides of the fuselage, and the lower wing must have interfered with the downward view. Originally the fuselage was built up high behind the cockpit and the engine was quite neatly cowled, but the high decking was later removed and replaced by a small head-rest, presumably to improve rearward view, and the engine cowling was removed, doubtless to improve cooling. The design of the vertical tail-assembly was also modified, and a four-bladed airscrew replaced the original two-blader.
The mainplanes were of unequal span and chord, were heavily staggered, and had rounded wing-tips reminiscent of those of the original Vickers F.B.12.
Late in 1916 the F.B.16 design was drastically revised, and the aircraft which emerged in December of that year bore very little resemblance to the original F.B.16. Only the shape of the tail-unit betrayed a relationship between the two aeroplanes.
The new machine was designated F.B.16A. The Hart radial engine was discarded and never again heard of, save as the power unit for which the F.B.24 two-seater was designed. Power for the F.B.16A was provided by a 150 h.p. Hispano-Suiza engine, and the fuselage was suitably re-designed to suit the vee-eight liquid-cooled engine, which was cleanly cowled with a frontal radiator. The sides of the fuselage were flat, but a shallow rounded fairing was applied to the underside and a rounded top-decking was fitted; a streamlined head-rest was fitted.
The sesquiplane wing arrangement was retained, but the mainplanes had straight raked tips. The tips of the tailplane were semicircular, and the fin and rudder were of characteristic elliptical outline. The armament consisted of a fixed Vickers gun and a Lewis gun on a sliding mounting on the upper wing.
Test flights of the first F.B.16A were made on December 20th, 1916, by Captain Simpson. The machine’s performance must have given him great confidence, for it is recorded that he “proceeded to loop, dive and stall” the F.B.16A. After the third loop, the spectators saw that all was not well, but Simpson regained control. When the aircraft was at a height of 50 feet it suddenly dived straight into the ground. The pilot sustained fatal injuries.
A second F.B.16A was built and was tested by Harold Barnwell. It was found that there was a weakness in the leading edges of the mainplanes. Presumably this was corrected, for an F.B.16A numbered A.8963 went on to Martlesham for official trials. Its performance proved to be excellent, but the type was not adopted. From the maintenance point of view the S.E.5 was probably a better design, and it was already in large-scale production.
Development of the Vickers design proceeded, however, and by June, 1917, A.8963 had been modified and redesignated F.B.16D. The chord of the upper wing was increased by 6 inches; gap and stagger were slightly increased; a larger fin and rudder were fitted; and narrower undercarriage vees were employed. The engine was a 200 h.p. Hispano-Suiza, and the armament was arranged in the same way as that of the Austin-Ball A.F.B.1: a Lewis gun was fixed in the vee formed by the engine cylinder blocks, and fired through the hollow airscrew shaft. The wing-mounted Lewis gun was retained.
The performance of the F.B.16D was exceptionally good: its maximum speed at 10,000 feet was no less than 135 m.p.h., and it could reach that height in about 10 minutes.
On June 22nd, 1917, the F.B.16D was flown at Joyce Green by Captain J. T. B. McCudden, M.C. (later Major McCudden, V.C., D.S.O., M.C., M. M., victor in 57 aerial combats), who was at that time a fighting instructor at that aerodrome. He was full of praise for its performance, but said that it “would not make a sound service proposition, as the engine is so inaccessible and hard to replace.” The Martlesham test report on the F.B.16D agreed with McCudden’s opinion, and was critical of the awkward engine installation.
Harold Barnwell called the F.B.16D “Pot-Belly”, in view of its deep, stubby fuselage, and the nickname survived even after the machine had passed into the ownership of McCudden, who used it as a personal transport. He flew it to Turnberry in 1918, when he was posted there as a fighting instructor; and it has been said that McCudden was flying the F.B.16D when he crashed and was killed at Auxi-le-Chateau on July 9th, 1918, while on his way to assume command of No. 60 Squadron. This last point is doubtful, however: an eye-witness of the crash described McCudden’s aircraft as an S.E.5a.
A further extensive re-design of the Vickers single-seat fighter produced the F.B.16E. This sub-type was powered by the 275 h.p. Lorraine-Dietrich, another French liquid-cooled vee-eight engine. The fuselage was longer than that of the F.B.16D, and the fin and rudder assembly was increased in area. Two-bay wings of increased span were fitted, and the main armament consisted of twin Vickers guns; the mounting of the Lewis gun was also retained. The engine had a frontal radiator which had shutters over its upper half.
The increased power gave the F.B.16E a slightly better performance than the F.B.16D, but the fastest sub-type of the F.B.16 series was the F.B.16H. This ultimate variant was fitted with the 300 h.p. Hispano-Suiza engine, and its airframe was identical to that of the F.B.16E.
Manufacturers: Vickers Ltd. (Aviation Department), Imperial Court, Basil Street, Knightsbridge, London, S.W.
Power: F.B.16: 150 h.p. Hart. F.B.16A: 150 h.p. Hispano-Suiza. F.B.16D: 200 h.p. Hispano-Suiza. F.B.16E: 275 h.p. Lorraine-Dietrich. F.B.16H: 300 h.p. Hispano-Suiza.
Weights (lb) and Performance:
Aircraft F.B.16A With Lewis gun F.B.16A Without Lewis gun F.B.16D F.B.16E F.B.16H
No. of Trial Report M.100 M. 100A M.126A - -
Date of Trial Report May, 1917 May, 1917 July, 1917 - -
Type of airscrew used on trial Vickers Series 154 Vickers Series 154 Vickers Series 192 - -
Weight empty 1,170 1,170 1,376 1,495 1,636
Military load 100 80 88 160 147
Pilot 180 180 180 180 180
Fuel and oil 224 224 231 365 337
Loaded 1,674 1,654 1,875 2,200 2,300
Maximum speed (m.p.h.) at
ground level - - - - 147
6,500 ft 120 - - - -
10,000 ft 116 - 135 137 140
13,000 ft - - 130 - -
15,000 ft 100 104 126 131 -
16,500 ft - - 122 - -
m. s. m. s. m. s. m. s. m. s.
1,000 ft 0 50 - - 0 45 - - - -
5,000 ft - - - - - - 3 30 3 20
6,000 ft - - - - 5 25 - - - -
6,500 ft 6 35 6 10 6 00 - - - -
10,000 ft 12 25 11 25 10 25 7 50 7 50
12,000 ft 17 18 - - 13 45 - - - -
14,000 ft 24 48 - - - - - - - -
15,000 ft 31 05 25 30 20 45 14 00 - -
16,000 ft 42 00 - - - - - - - -
17,000 ft - - - - 28 10 - - - -
19,000 ft - - - - 43 30 - - - -
20,000 ft - - - - - - - - 23 30
Service ceiling (feet) 15,000 16,000 18,500 24,000 -
Endurance (hours) 2 1/4 - 2 1/4 2 -
Petrol (gallons) 28 3/4 28 3/4 28 - 40
Oil (gallons) 2 1/2 2 1/2 3 1/2 - 5
Water (gallons) 6 6 7 3/4 - -
Armament: F.B.16: One fixed, forward-firing Vickers machine-gun mounted above the fuselage and synchronised to fire through the airscrew. F.B.16A: One Vickers machine-gun, fixed and synchronised to fire forward through the airscrew; one Lewis machine-gun on sliding mounting above starboard upper wing root. F.B.16D: Two Lewis guns, one mounted in the vee of the engine cylinder blocks and firing forward through the hollow airscrew shaft, the second above the upper wing as on the F.B.16A. F.B.16E and 16H: Two fixed, forward-firing Vickers guns within the cowling above the engine, synchronised to fire through the airscrew. The F.B.16E at least retained the mounting for the Lewis gun.
F.B.16A F.B.16D F.B.16E F.B.16H
ft in. ft in. ft in. ft in.
upper 25 0 25 0 31 0 31 0
lower 22 4 22 4 30 0 30 0
Length 19 0 19 6 21 0 21 8
Height 7 10 8 9 - - 8 1
upper 5 0 5 6 5 4 5 4
lower 4 2 4 2 4 2 4 2
Gap 3 9 3 11 3 9 3 9
Stagger 2 2 2 6 2 5 2 5
Dihedral 1° 30' 1° 30' 1° 30' 1° 30'
Incidence 2° 2° 2° 2°
F.B.16A F.B.16D F.B.16E F.B.16H
sq ft sq ft sq ft sq ft
upper 118 126 158 158
lower 81 81 114 114
total 199 207 272 272
each upper - - 9-5 9-5
each lower - - 6 6
total 27 23-5 31 31
Tailplane 18-5 18-5 18-5 18-5
Elevators 15-3 15-3 15-3 15-3
Fin 3-75 6-5 7 7
Rudder 5 6 6-5 6-5
Service Use: The Vickers F.B.16D was used by Capt J. T. B. McCudden, and was taken by him to the School of Aerial Fighting at Turn berry. Official statistics show that one Vickers F.B.16 (sic) was sent to a training unit in 1917.
Serial Numbers: A.8963: built as F.B.16A with Engine No. 5691 under Contract No. A.S.589; modified to become F.B.16D with Engine No. 869/2233, Series III, W.D.8444.
H.King Armament of British Aircraft (Putnam)
F.B.16. The original F.B.16 single-seat fighter (built mid-1916) had one Vickers gun mounted centrally ahead of the pilot, with the coaming rising sharply to fair-in the breech casing. Ejection chutes low in the flanks of the fuselage indicate that the system devised by G. M. Challenger, which will be described and illustrated in Volume 2, was incorporated. The F.B.16A likewise had a centrally mounted Vickers gun, but in this instance the gun was enclosed in a long fairing and was supplemented by a Lewis gun mounted above the centre-section. The F.B.16D had no Vickers gun, but in addition to a Lewis gun mounted above the top wing, offset to starboard, there was a second Lewis gun mounted between the cylinder banks of the Hispano-Suiza engine and firing through the hollow airscrew shaft. Sharply contrasting in armament was the F.B.16E, with its two Vickers guns in long fairings ahead of the cockpit and a bracket for a Lewis gun on the rear spar of the top wing, offset to starboard. Armament weight was given as 176 lb, suggesting that installation of the Lewis gun was a firm intention.
Jane's All The World Aircraft 1919
THE VICKERS F.B. 16 H.
The Vickers F.B. 16 H. is a single-seater fighting Scout type. The planes are rather heavily staggered and fitted with two pairs of interplane struts either side of the fuselage. No centre section is fitted, the planes being fixed direct to the inverted Vee type pylons in front of the pilot's seat. The upper plane is well cut away over the pilot's cockpit to give a clear view upwards.
The tail-unit consists of a large fin and unbalanced rudder and a tail plane and divided elevator, the fin and tail plane being well braced above and below with Rafwire lacing.
The elevator controls are outside the fuselage.
The armament consists of two fixed Vickers guns which are fitted inside the fuselage synchronised to fire to the propeller.
Type of machine Tractor Biplane, single-seater
Name or type No. of machine F.B. 16 H.
Purpose for which Intended Fighter.
Span T. 31 ft.; b. 30 ft.
Gap, maximum and minimum 45 ft.
Overall length 21 ft. 8 In.
Maximum height 8 ft. 1 in.
Chord T. 5 ft. 4 in.; b. 4 ft, 2 In.
Total surface of wings 272 sq. ft.
Span of tall 11 ft.
Total area of Tail 33.8 sq. ft.
Area of elevators 15.3 sq.ft.
Area of rudder 6.5 sq. ft.
Area of fin 7 sq. ft.
Area of each aileron and total area 2 x 9.5+2 x 6 = 31 sq. ft.
Maximum cross section of body 8 sq. ft.
Horizontal area of body 36 sq. ft.
Vertical area of body 57 sq. ft.
Engine type and h.p. Hispano-Suiza; 300 h.p.
Airscrew, diam., pitch and revs 8 ft. diam., 6 ft. pitch, 1,875 r.p.m.
Weight of machine empty 1,636 lbs.
Load per sq. ft. 8.45 lbs.
Weight per h.p. (800 h.p.) 7.65 lbs.
Tank capacity in gallons Petrol 40 galls; oil 5 galls.
Speed low down 147 m.p.h.
Speed at 10,000 feet 140 m.p.h.
Landing Speed 53 m.p.h.
To 5,000 feet 3,3 minutes.
To 10.000 feet 7.8 minutes.
To 20 000 feet 23.5 minutes.
Disposable load apart from fuel
(including crew) 327 lbs.
Total weight of machine loaded 2,300 lbs.
Flight, June 12, 1919.
THE VICKERS MACHINES
The F.B. 16. (Dec, 1916)
This machine was a small tractor scout designed to take the Hart engine. As the Hart engine was still only in the experimental stage, the machine was modified to take the 150 h.p. Hispano-Suiza engine. It was ready in December, 1916.
On December 20, 1916, Messrs. Vickers' test pilot, the late Mr. Barnwell, being then indisposed, the late Capt. Simpson, R.F.C., was deputed to make the test flights. He proceeded to loop, dive and stall, and after the third loop, it was observed by those on the ground that something was happening to the planes. However, the pilot regained control, and at 50 ft., when everybody thought that the danger had been overcome, the machine suddenly dived straight into the ground, Capt. Simpson sustaining fatal injuries. After a full enquiry, instructions were received by Messrs. Vickers, Ltd., from the War Office to build another machine similar in every detail. The second machine was ready in January, 1917, and was tested by the firm's own pilot. By careful and systematic investigation, it was discovered that the weakness lay in the leading edges of the planes. This was an unforeseen trouble arising out of the general increase in the speed of aircraft at this period. It is of interest to note that the same trouble developed in a contemporary machine which was ultimately fitted with a solid 3-ply leading edge to overcome this difficulty.
This second F.B. 16, known as the F.B. 16A, was then sent on to the Testing Squadron at Martlesham Heath, from where an excellent report on its all-round performance was received. According to official tests, it beat the S.E. 5 and other types with similar engines, but the Air Board rightly decided that it would be unwise to disturb production of existing orders at a critical time.