O.Tapper Armstrong Whitworth Aircraft since 1913 (Putnam)

F.K.8

   It was presumably a coincidence that two types of aircraft designed in 1916 for corps-reconnaissance duties should both bear the number 8 as their type designation; certainly, in all other respects they could not have been more dissimilar. The Armstrong Whitworth F.K.8 and the R.E.8, designed by the Royal Aircraft Factory, were both intended as B.E.2c replacements, and it was unfortunate for the long-suffering reconnaissance pilots of the RFC that it was the inferior R.E.8 that was chosen for massive production at the expense of the more popular F.K.8. Nevertheless, the F.K.8 was produced in considerable numbers and played a significant, if unspectacular, part in the war from the beginning of 1917 until the Armistice, including actions which led to the award of two Victoria Crosses.
   Although designed for the same duties as its predecessor, the F.K.8 represented a considerable advance over the F.K. 3; it was planned from the start to accommodate internally all the various trappings of army cooperation, such as cameras, which, in previous types had been hung on outside with a noticeable effect on the aircraft's performance. The result, in the F.K.8, was a fuselage of ample proportions with comfortable separate cockpits for pilot and observer.
   In construction the F.K.8 was a conventional biplane with two-bay wings of equal span and greater dihedral on the top plane than on the bottom. The upper wing was built in two portions which met on the centre line at the apex of two inverted-V centre-section struts. The controls were conventional; ailerons were fitted to all four wings and the incidence of the tailplane was adjustable by means of a handwheel in the pilot's cockpit. The observer was provided with a rudimentary method of control in the shape of a side-mounted stick to operate the elevators, and hand grips on the rudder control cables where they passed through the observer's cockpit. There was no means of operating the ailerons from this position but, as was shown several times in practice, it was quite possible to fly the aircraft satisfactorily without the aid of the ailerons and there were a number of occasions on which the aircraft was brought back safely by the observer after the pilot had been incapacitated.
   The undercarriage was of similar design to that of the F.K.3, with oleo shock-absorbers mounted on the fuselage sides and with a central skid which, in the case of the F.K. 8, was truncated at the forward supporting struts. In April 1917 the RFC headquarters in France reported that the F.K.8's undercarriage was unsatisfactory and suggested that it should be replaced by a plain V-type specimen from a Bristol Fighter. This modification proved a big improvement and No.1 Aircraft Depot proceeded to convert a number of aircraft until, in the following July, the supply of Bristol Fighter undercarriages dried up and B.E.2c undercarriages had to be used instead. The gauge of tube used and the angle of the V was the same in both types, but the rear legs of the B.E. landing gear were shorter. This seems to have been of no great significance. Later, a modified type of undercarriage with a wider V appeared, and this may have been the production version fitted by the makers. The simpler type of landing gear improved the climb performance and raised the top speed by about 5 mph.
   There is a widely-held opinion that the first production F.K.8s were powered by the 120 hp Beardmore engine, but in the light of recent research this belief is now thought to have been due to a misunderstanding. As already mentioned, both Armstrong Whitworth and the Service authorities were unusually lax in differentiating between the F.K.3 and the F.K.8, and this seems to have led to some confusion over the powerplants as well as over production figures. The mistake probably arose in the first place because the small batch of F.K. 3s fitted with the 120 hp Beardmore engine, as described earlier, were loosely referred to as 'Armstrong Whitworth 120 hp biplanes' and, because this variant was little known, it was naturally assumed that this description applied to the F.K.8. Apart from a statement in Jane's All the World's Aircraft for 1918 which was repeated in the following year and which may well have been the original source of the misunderstanding, there is a marked absence of direct evidence in favour of the 120 hp engine, and all the indications are that the F.K.8 was powered by the 160 hp Beardmore from the start.
   During the course of production, other engines were tried out experimentally in the F.K.8. Two aircraft, B214 and B2l5, were fitted with variants of the twelve-cylinder air-cooled RAF 4 engine, the type which had, by its early unreliability, added to the unpopularity of the R.E.8. Another aircraft, A2696, was fitted with a Lorraine-Dietrich engine of 150 hp, but none of these engines bestowed any significant improvement on the F.K.8's performance and there was no move to adopt them as standard.
   As first produced, the F.K.8 had a somewhat angular form of engine cowling, which gave the aircraft a vaguely Germanic appearance, and a crude form of radiator consisting of honeycomb blocks mounted on the sides of the fuselage and extending upwards and inwards to meet at a point in front of the top wing. This radiator proved to be inefficient in service and, as a result of a flood of complaints from the Western Front, a new type was adopted. This new radiator, which consisted of two elements mounted one each side of the fuselage, proved more effective as a radiator as well as improving the view from the cockpit. With the new compact type of radiator, a more rounded form of cowling was introduced, changes which resulted in a marked improvement in the appearance of the machine.
   Another complaint voiced by Service pilots concerned the distortion of the view caused by the mirage effect of the fumes from the stub exhaust pipes. To overcome this, some enterprising officers of No. 10 Squadron in France devised and constructed a stack-type exhaust pipe which carried the fumes over the top wing. Permission was granted by RFC HQ in France for tests to be made with this exhaust system, but a warning was given that the large side area of the stack might affect the directional stability of the aircraft, and the advice was added that '... pilot ought to be warned not to do any short turns near the ground with it'. In fact, tests showed that there was no deterioration in directional stability, and the pilots of No. 10 Squadron were favourably impressed with the improvement in visibility and the fact that the after part of the aircraft was no longer smothered in oil: it was, however, noted that the design would have to be strengthened to withstand vibration. In the end this design was not adopted, but a modified system, consisting of a long exhaust pipe extending to a position aft of the observer's seat, was introduced.
   The first flight of the F.K.8 took place in May 1916, and in the middle of the following month an F.K.8 numbered A411, which was almost certainly the prototype, was flown by a Service pilot from Newcastle to the Central Flying School at Upavon for official tests. The journey took two days, 16 and 17 June, and the pilot reported favourably on the aircraft's handling qualities. The tests by the CFS pilots were carried out on 18 and 19 June, and the top speed of the aircraft, the average of six runs over a measured course, was recorded as 98·4 mph. In the official report the F.K.8's performance was compared with that called for in the specification; it achieved 93 mph at 8,000 ft, as against the 100 mph called for, and it climbed to that height in 20 min, 4 min longer than the specified time. A criticism was made that the tailskid was not strong enough; later this fault was the cause of numerous complaints from the Western Front and, in 1917, the rudder shape was modified to avoid damage to its base when the skid broke. The test pilot also noted that when the aircraft was trimmed to fly level at 70 mph, it glided fast at 90 mph when the throttle was closed and that it would be an advantage if this tendency could be corrected. To this rather naive comment was added the remark that the aircraft would be good for reconnaissance but poor for bombing. Later, a cut-out between the spars at the root of the lower wing was provided to improve the pilot's view directly downwards. After tests at Upavon the F.K.8, A411, was returned to the makers for experimental work.
   For reasons already stated when dealing with the F.K.3, production figures for the F.K. 8 are not now readily obtainable. The first production order for the F.K.8 was apparently that placed at the beginning of August 1916 with Armstrong Whitworth under contract 87/A/508, and such records as are available indicate that this, and two other contracts placed with Armstrong Whitworth, covered a total of 701 aircraft, not including the prototype. The F.K.8 was also built in large numbers by Angus Sanderson & Co, another Newcastle firm which had previously cooperated with Armstrong Whitworth by building bodies for their motorcars. Orders for some 950 F.K.8s were placed with this firm, which brings the total number of F.K.8s ordered to at least 1,652. By the end of 1917 between eighty and one hundred F.K.8s a month were coming off the Armstrong Whitworth line at Gosforth, and the type continued in production there until July 1918, by which time arrangements had been made for Angus Sanderson to continue with F.K.8 production while Armstrong Whitworth turned their attention to building the Bristol Fighter.
   The first production F.K.8s were emerging from the Armstrong Whitworth factory at Gosforth at the end of 1916, and there are reports of individual aircraft being with the RFC in France before the year ended. However, the first squadron to be fully equipped with the type was No.35, which received its F.K.8s before proceeding to France in January 1917. Then came a gap until June, when No.2 Squadron, already in France, had its RE.s replaced by F.K.8s, which continued to be the squadron's equipment until the Armistice. Other squadrons in France which used the F.K.8 through to 1918 were Nos. 8, 10 and 82, while in the Near East the type, among others, was used by No.17 Squadron in Salonika and by No.142 in Palestine. The F.K.8 also formed part of the mixed equipment used in 1916 and 1917 for home defence by Nos. 36,47 and 50 Squadrons. It was an F.K.8 of No.50 Squadron, flown by 2nd Lieut F. A. D. Grace and 2nd Lieut G. Murray, that scored one of the few victories against a raiding Gotha, shot down in the North Sea on 7 July, 1917. The F.K.8 was also used quite extensively for training at home, particularly in the specialized arts of army co-operation, photography, map reading and reconnaissance.
   In France the F.K.8 undertook a multitude of duties including night and day bombing, reconnaissance, artillery spotting, photography, trench straffing and even the dropping of supplies to forward troops. It was, like the RE.s before it, a maid of all work, but, unlike them, it was capable of putting up a fair degree of resistance when attacked, and had relatively good performance. The observer, with a Scarff mounting for his Lewis gun, had a good field of fire, while the pilot could operate a forward-firing, synchronized Vickers machine-gun. This defensive armament was used to good effect on 29 November, 1917, when Lieuts Pattern and Leicester, after a prolonged fight with five enemy fighters, succeeded in shooting down the German 'Ace' Erwin Bohme.
   The battle-worthiness of the F.K.8 was demonstrated on two other occasions which, as already mentioned, resulted in the award of the Victoria Cross to two pilots. On 27 March, 1918, 2nd Lieut A. A. McLeod of No.2 Squadron with Lieut A. W. Hammond as his observer, flying in B5773, were attacked by eight Fokker Triplanes. In spite of being repeatedly wounded, between them the British pair accounted for four of the enemy before their aircraft, already severely damaged, caught fire. Lieut McLeod was forced by the flames to climb out of his cockpit but while standing on the wing managed to control the aircraft by manipulating the control column with one hand, side-slipping away from the flames and directing it towards the Allied lines; meanwhile Hammond, who had been wounded no less than six times, continued to hold the enemy at bay with his machine-gun. In spite of his wounds and the flames, McLeod Succeeded in bringing his aircraft to a comparatively soft crash landing in no-man's land from which both officers were rescued, still under heavy fire, by the infantry. The second F.K.8 pilot to be awarded the Victoria Cross was Captain (later Air Commodore) F. M. F. West of No.8 Squadron who, with his observer Lieut J. A. G. Haslam, was returning from a low-level bombing attack on German gun positions when his aircraft was attacked by six fighters. Although severely wounded in the legs, West managed to fly back to the Allied side of the lines and then refused to allow himself to be taken to hospital until he was able to pass on some important information about enemy troop concentrations.
   The sturdy F.K.8 continued to serve on the Western Front until the war ended. At that time there were 182 of them in France, with 320 aircraft in reserve or under repair at home. Outside Europe there were fifty-six F.K.8s in Egypt and Palestine, forty-four in Salonika and two in the North West Province of India. In Great Britain there were sixty-nine aircraft on home airfields, mostly with training units.
   After the war's end, the F.K.8 quickly faded from the scene in the RAF, and only eight found their way on to the British civil register; of these, three were sold abroad while the others were all crashed or otherwise written off before the end of 1920. The F.K.8's sole claim to fame in civil aviation is that of flying the first regular airmail service to be operated by a small Australian company, Queensland and Northern Territory Aerial Services Ltd, later to become better known as QANTAS. Formed in 1920 by two ex Australian Flying Corps pilots, W. Hudson Fysh and P. J. M. McGinnis, the company had been operating a successful hire service from their base at Longreach using a mixed fleet consisting of an Avro 504K with a Sunbeam Dyak engine, a D.H.4, an Avro Triplane, and two F.K.8s bearing the registrations G-AUCF and G-AUDE.
   In 1922 the company was given a contract to operate a mail service between Charleville and Cloncurry with principal stops at Blackall, Longreach and Winton, railheads all connecting with the coast railway but not directly with each other. The route distance of 577 miles was scheduled to be flown in two days, with a night stop about half way at Longreach. The first service, which left Charieville at 5.30 a.m. on 2 November, 1922, was flown by McGinnis in the F.K.8 G-AUDE and carried a mail package containing 106 letters; it arrived at Longreach at 10.15 a.m., having averaged 82 mph excluding stops. The Longreach Cloncurry sector was scheduled to be flown on the following day by Hudson Fysh using the other F.K.8, G-AUCF, but, due to a slight drop in engine revolutions, this aircraft failed to take-off in the high temperature and G-AUDE was pressed into service again. This time the take-off was successful and the aircraft was soon on its way carrying the mail and one passenger, an 87-year-old settler named Alexander Kennedy.
   The F.K.8s gave good service to QANTAS despite the fact that the rate of climb seldom exceeded 500 feet a minute and was often considerably less in the full heat of the day. At first some trouble was experienced with engines overheating, but this was cured by the fitting of larger radiators and a header tank which served to condense the steam if the radiator water did boil.
   Thus, both in war and in peace, the F.K.8 carved for itself a positive niche in history for which it has received scant recognition, either in the annals of the time or since: perhaps it was its very qualities of stolid strength and reliability and its consistent but unspectacular performance which made everyone accept it and then forget about it.


F.K.8

   Dimensions: Span 43 ft 6 in (13.26 m); length 31 ft 5 in (9.58 m); height 10 ft 11 in (3.33 m); wing area 540sq ft (50.17 sq m).

   160 hp Beardmore 150 hp Lorraine Dietrich 150 hp RAF 4A
Max weight: 2,811 lb(1,275kg) 2,816 lb(1,277kg) 2,827 lb (1,282 kg)
Empty weight: 1,916 lb(869kg) 1,936 lb(878 kg) 1,980 lb (898kg)
Max speed
   Sea level: 95 mph (153km/hr) - -
   6,500 ft(1.981 m): - 89 mph (143 km/hr) 94mph(151 km/hr)
   8.000 ft(2,438 m): 88 mph (142 km/hr) - -
   10,000 ft(3,048 m): - 83 mph (134 km/hr) 89 mph (143 km/hr)
Climb to
   6.500 ft(1.981 m): 15.4 min 16.5min 16.4min
   8,000 ft(2,438 m): 20 min - -
   10,000 ft(3.048 m): 27.8 min 33.2 min 32 min
Service ceiling: 13,000 ft. (3,962 m) 11,000 ft (3.353 m) 12,000 ft. (3.658 m)
Fuel capacity: 50 Imp gal (227 lt) 50 Imp gal (227 lt) 50 Imp gal (227 lt)
Endurance: 3 hr 4 hr 3 hr

F.Manson British Bomber Since 1914 (Putnam)

Armstrong, Whitworth F.K.7 and F.K.8

   The role of corps reconnaissance must have been one o f the least popular of the duties undertaken by RFC flying personnel during the First World War, and on account of the appalling casualties suffered by the B.E. aircraft over a period of two years, Service pilots tended to be extremely critical of the aeroplanes they were obliged to fly. This was particularly true of the B.E.s themselves, as well as the R.E.8 which was intended to replace them. Frederick Koolhoven, aircraft designer with Sir W G Armstrong, Whitworth Aircraft Ltd, having produced what he considered to be 'an improved version of the B.E.2C with his F.K.3, went further with his bigger and more powerful F.K.8 - predictably known as the 'Big Ack'. As such, the latter was seen to be comparable with the Factory's R.E.8. In terms of performance it was found to be inferior, but this was more than balanced by it being fairly free of handling vices. Moreover, in contrast to the apparent unwillingness to effect improvements in the R.E.8 (for a number of possibly valid reasons), the makers of the F.K.8 went to some effort to improve the features that attracted criticism in their aeroplane.
   Design of the F.K.8 was orthodox and incorporated the increased strength factors being recommended by the Factory on behalf of the War Office by 1916. Like its predecessor, it was a two bay staggered biplane with ailerons on upper and lower, equal-span wings. Contrary to suggestions that persisted for years, the F.K.8 was powered from the outset by the 160hp Beardmore engine, a powerplant of approximately the same power/weight ratio as the R.E.8's 140hp R.A.F.4A. However the installation of the straight-six, watercooled Beardmore was untidy, with angular cow ling panels and large vertical radiator blocks attached to each side of the nose and angled inwards to meet at a point on the aircraft's centreline above the engine; the provision of cumbersome exhaust manifolds and the triple V-strut undercarriage with oleo struts on the sides of the fuselage all conspired to limit the F.K.8's speed performance. Indeed, the maximum speed of 95 mph at sea level was 5 mph below that considered essential for corps reconnaissance machines, and 8 mph slower than the R.E.8.
   Despite these shortcomings, Koolhoven's aeroplane probably became more popular among its pilots, being straightforward and relatively simple to fly, as well as possessing a robust airframe capable of withstanding battle damage.
   The prototype, F.K.7 A411, first flew in May 1916, and acceptance tests were flown at Upavon the following month. The first production orders were placed with Armstrong, Whitworth in August, and the first deliveries were made from Gosforth before the year's end, several aircraft joining No 55 Training Squadron at Lilbourne in December. The first examples to fly with a front-line squadron were delivered to No 35 Squadron, which took a full complement to St Omer in France on 25 January 1917. By the end of that fateful April No 35 had been joined by No 2 Squadron, as demands for improvements in the aircraft were already being received by the manufacturers.
   Apart from severely restricting the pilot's forward vision, the long, angled radiator honeycomb blocks were inefficient and were replaced by much smaller blocks attached lower on the sides o f the nose. At about the same time the nose cowling was improved in shape, the angular panels giving place to a more rounded profile in side elevation. The crude engine exhaust manifold, whose efflux was found to distort the crew's field of vision through mirage effect, was eventually changed to a conventional pipe which extended aft of the cockpits.
   The undercarriage was also criticized as unsatisfactory, and the RFC suggested using components of the Bristol Fighter's plain V-strut gear, a proposal adopted by No 1 Aircraft Depot, where several such conversions were undertaken - until stocks of the Bristol components ran out and resort was made to the use of B.E.2C parts! In due course Armstrong, Whitworth came up with its own improved plain-Y design, still retaining the oleos located in the fuselage sides, but significantly improving the aircraft's performance.
   The F.K.8 was ordered in large numbers. Oliver Tapper suggests that the total production amounted to at least 1,652 aircraft, but explains that the exact number may never be known owing to the absence of differentiation between F.K.3s and F.K.8s in some contract documents. Yet, despite this relatively large number of aircraft, the F.K.8 only served on a total of six squadrons in France, and three in the Balkans and Palestine. Three squadrons, based in the United Kingdom, flew the aircraft on home defence and training duties.
   Like the R.E.8, the F.K.8 also undertook bombing raids on the Western Front, commencing in September 1917, and later in Macedonia. The aircraft was capable of carrying up to four 65 lb bombs, but more frequently mounted six 40 lb Bourdillon phosphorus weapons, especially when required to lay smokescreens in support of ground forces.
   It was while the Big Acks were engaged in bombing operations that two pilots won Victoria Crosses. On 27 March 1918, while returning in the F.K.8 B5773 from a raid during the German offensive on the Western Front, 2/Lieut Alan A McLeod was attacked by a Fokker Dr I triplane, which was quickly shot down by his observer, Lt A W Hammond MC. They were then attacked by seven more Fokkers, of which four were shot down two by McLeod with his front gun. Both crew members were badly wounded, the pilot being hit five times and severely burned when his fuel tank was set on fire. Despite great pain, McLeod climbed out on to the port wing but managed to retain his hold on the control column and, by sideslipping, kept the flames away from the cockpit as he crash landed in No Man's Land, where the two airmen were rescued by British troops. Both miraculously survived, although Hammond lost a leg; McLeod, who was only eighteen years of age, was awarded the Victoria Cross, and Hammond a Bar to his Military Cross.
   During a period in the summer of 1918, when F.K.8s were taking part in trials with No 8 Squadron in co-operation with the Army's tanks on the Western Front, the second Victoria Cross was won by a Big Ack pilot. On 10 August, as Capt Ferdinand Maurice Felix West Mc and Lt J A G Haslam (later Gp Capt, MC, DFC) were returning from a bombing raid on German gun batteries, their F.K.8 was attacked at low level by six enemy fighters. Despite Heine hit in both legs, one of which was almost severed, and scarcely conscious owing to excruciating pain and loss of blood, the 22-year-old pilot managed to land in the British lines, yet refused to be taken to hospital until he had passed his vital report to the local tank commander. West's Victoria Cross was gazetted three days before the Armistice, and this officer continued to serve in the RAF until his retirement in March 1946 as an Air Commodore.
   The F.K.8 survived in service for a few months after the War, the last Squadron, No 150, being disbanded at Kirec in Greece on 18 September 1919.

   Type: Single-engine, two-seat, two-bay tractor biplane for ground support and short-range bombing.
   Manufacturers: Sir W.G. Armstrong, Whitworth & Co, Ltd., Gosforth, Newcastle-upon-Type; Angus Sanderson & Co, Newcastle-upon-Tyne.
   Powerplant: One 160hp Beardmore six-cylinder water-cooled inline engine driving two-blade propeller. Experimental installations: 150hp R.A.F.4A and 150hp Lorraine Dietrich.
   Structure: All-wood wire-braced construction with partial dual flying controls and oleo-sprung undercarriage.
   Dimensions: Span, 43ft 6in; length, 31ft 0in; height, 10ft 11in; wing area. 540 sq ft.
   Weights: Tare, 1,916 lb; all-up, 2,811 lb.
   Performance: Max speed, 94 mph at sea level; climb to 5,000ft, 11 min.; service ceiling, 13,000ft; endurance, 3 hr.
   Armament: One forward-firing, synchronized 0.303in Vickers machine gun, and one Lewis or Vickers machine gun on Scarff ring on rear cockpit; provision for bomb load, normally comprising up to six 40 lb, four 65 lb or two 112 lb bombs on underwing racks.
   Prototype: One F.K.7 prototype, A411, first flown in May 1916.
   Production: Total of 1,652 F.K.8s stated as being delivered to the RFC and RAF prior to 1st September 1918, including 210 probably in component form only. Armstrong, Whitworth, 650 (A2683-A2372, A9980-A9999, B201-B330, B3301-B34OO, B5751-B5850 and C8401-C8650). Angus Sanderson, 600 (C3507-C3706, F7347-F7546 and H4425-H4624). 330 further aircraft were ordered (D5001-D5200, F616-F645 and H4625-H4724) but not all are known to have been completed, and their manufacturers have not been confirmed. Upwards of 40 aircraft were repaired and rebuilt, being re-allocated various isolated B, F, and H-prefixed numbers.
   Summary of Service: F.K.8s served operationally with Nos 2, 10, 35, 55 and 82 Squadrons, RFC and RAF, and on tank co-operation trials with No 8 Squadron on the Western Front; with Nos 17, 47 and 150 Squadrons in Macedonia; and with No 142 Squadron in Palestine. They also served with Nos 31, 39 and 98 (Training) Squadrons, No 50 (Home Defence) Squadron, Schools of Army Cooperation, School of Photography, Air Observer and Air Gunnery Schools and other training units.

P.Lewis British Bomber since 1914 (Putnam)

May, 1916, saw the first flight of a new two-seat bomber and reconnaissance biplane, the Armstrong Whitworth F.K.8 designed by Koolhoven. A compact, clean design, it was to remain relatively little publicized and yet performed well and reliably on active service. A neatly-cowled 120 h.p. Beardmore, flanked by upright radiators which slanted inwards to meet at the upper centre-section, was installed in early F.K.8s, but greater power was available from the 160 h.p. Beardmore which was fitted subsequently. Stagger was built into the equal-span two-bay wings, and the undercarriage at first followed the style of the F.K.3 with a central skid. In the course of its production career various alterations were made, including the adoption of a simpler main undercarriage unit. No. 35 Squadron, R.F.C., was the first to go into action with the F.K.8, popularly called the Big Ack, taking them to France on 24th January, 1917.

J.Bruce British Aeroplanes 1914-1918 (Putnam)

Armstrong Whitworth F.K.8

  TWO of the nineteen V.C.s awarded to members of the British flying services during the 1914-18 war were won on Armstrong Whitworth F.K.8s, yet the type is one of the less well-known aircraft of its period. Why this should be so is something of a mystery, for the F.K.8 gave excellent service on several fronts and proved itself a redoubtable opponent to the German single-seat fighters on more than one occasion. A possible reason for its obscurity might be that it did a good job of work, unobtrusively and without attracting undue praise or blame. It was popular with its pilots, to whom it was familiarly known as the “Big Ack”.
  The F.K.8 was, of course, designed by Frederick Koolhoven, and bore a family resemblance to the earlier F.K.3. Like the F.K.3, it had staggered wings with two-bay bracing and greater dihedral on the upper wings than on the lower, and the vertical tail assembly was of typical Koolhoven design.
  The prototype F.K.8 flew in May, 1916, and the first R.F.C. squadron to have the type was No. 35, which went to France fully equipped with F.K.8s on January 24th, 1917. No. 2 Squadron began to reequip with Big Acks in April, 1917; No. 10 received the type in July, 1917, No. 8 in August, 1917, and No. 82 went to France on November 20th, 1917, with the F.K.8 as its equipment. With these units in France, with Squadrons Nos. 17 and 47 in Macedonia, and with No. 142 in Palestine, the Big Ack gave sterling service as a reconnaissance and bombing machine until the Armistice.
  The standard production F.K.8s had at first the 120 h.p. Beardmore engine, but later the 160 h.p. Beardmore was fitted. The engine cowling was at first a decidedly angular affair in which straight lines predominated, but later machines had a redesigned nose which was rounded in side elevation. There were long upright radiator blocks on either side of the fuselage, their upper halves forming an inverted V immediately in front of the centre line of the upper mainplane. The original distinctive undercarriage was a peculiar and rather complicated version of the old horizontal skid type, and shock absorption was by oleo members, as on the F.K.3.
  Structurally, the F.K.8 had little to distinguish it, for it was a typical wire-braced biplane of wooden construction, but it had one feature which was uncommon in a British machine: namely, the use of inverted vee struts connecting the upper wings to the fuselage and the consequent absence of a centresection. Dual control was fitted: a small control column was provided on the starboard side of the observer’s cockpit, and was connected by an external link-rod to the starboard control arm from. which cables ran aft to the elevators. The observer thus had control over the elevators but not over the ailerons; and the rudder cables were provided with handgrips where they passed inside his cockpit, in order to give him emergency use of the rudder. The tailplane was adjustable, and was trimmed by a handwheel on the starboard side of the pilot’s cockpit.
  The F.K.8 was well-liked by its crews, who regarded it as being strong and easy to fly. By the end of 1917 Big Acks were leaving the Armstrong Whitworth works at a rate of more than eighty per month, and production continued until July, 1918.
  The final production version of the F.K.8 had the 160 h.p. Beardmore engine and retained the cleaner cowling, but improved radiators of reduced size were fitted, and on some machines a long horizontal exhaust pipe replaced the manifold with two short outlets which was more widely used. The most noticeable modification lay in the fitting of a plain vee undercarriage of more conventional design. As the illustrations show, two slightly different types of vee undercarriage were fitted.
  Other motors fitted experimentally to the F.K.8 were the 150 h.p. R.A.F. 4a and the 150 h.p. Lorraine-Dietrich, the latter installation being characterised by an enormous spinner on the airscrew and twin exhaust stacks. These exhaust stacks were large and had a pronounced backwards rake. Machines to which the R.A.F. 4a was fitted were B.214 and B.215, and A.2696 had the Lorraine-Dietrich.
  During the German offensive of March, 1918, the Big Acks did good work. On March 21st the machines of No. 35 Squadron dropped one hundred and sixteen 25-lb bombs and fired hundreds of rounds of ammunition on enemy troops and transport in the Maissemy area. They also directed artillery fire on to targets of massed infantry and cavalry with telling effect. Night bombing was another task allotted to the F.K.8s.
  It was during this German offensive that Second Lieutenant Alan A. McLeod of No. 2 Squadron won the Victoria Cross for the action fought by him and his observer, Lieutenant A. W. Hammond, M.C., on March 27th, 1918. These two officers of No. 2 Squadron were returning from a bombing raid when they were attacked by a Fokker Dr.I, Hammond promptly shot it down, but seven more Fokkers appeared and McLeod was wounded after destroying one of them. Hammond shot down two more, but was wounded six times, and the F.K.8 was so badly damaged that the floor of the rear cockpit fell out. Hammond was barely conscious and McLeod had five wounds when the petrol tank was hit and flames engulfed the front cockpit.
  Despite his wounds, McLeod climbed out on to the port wing and, with one hand on the burning control column, side-slipped to keep the flames away until the machine crashed in No-Man’s-Land. Hammond continued to fire at the remaining Fokkers until the crash knocked him unconscious. McLeod dragged him towards the British lines, receiving a sixth wound from a bomb-splinter while doing so. British troops rescued both airmen, who miraculously recovered from their terrible wounds, though Hammond suffered the amputation of one of his legs. Notification of the award of McLeod’s V.C. came through in due course, and Hammond received a bar to his M.C. McLeod was eighteen years old at the time.
  The Big Acks of No. 8 Squadron took part in experiments in cooperation with tanks in 1918, for which purpose the unit was attached to the Tank Corps on July tst, 1918. Officers of the squadron exchanged duties with officers of the tank units, and significant experiments were conducted with radio telephony as a means of communication between the air observers and the tank crews. The short range of the early R/T apparatus led to the substitution of wireless telegraphy at the end of July, but these experiments were too late for a procedure to be devised before the Armistice.
  It was an officer of No. 8 Squadron who won the second V.C. to be awarded to an F.K.8 pilot. On August 10th, 1918, Captain F. M. F. West, with Lieutenant J. A. G. Haslam as his observer, had dropped his bombs on an enemy gun position, and was still flying low when he was attacked by six enemy fighters.
  Their first burst of fire almost severed his left leg, and no sooner had he lifted his useless limb clear of the controls than he was hit again in the other leg. Although faint from loss of blood and half-dead with pain, West managed to keep the F.K.8 on an even keel while Haslam drove off the attackers. West eventually landed in the British lines and refused to go to hospital until he had given the Tank Commander a detailed report of the enemy concentration points.
  An unusual duty fell to the Big Acks of No. 35 Squadron on October 8th, 1918. It consisted of the maintaining of a smoke screen for two hours over the ground in front of the attacking British XIII Corps, west of Serain. The screen was produced and maintained by the continuous dropping of 40-lb phosphorus bombs by relays of aircraft.
  A few Armstrong Whitworth F.K.8s were used on Home Defence duties, and one of those belonging to No. 50 (Home Defence) Squadron shot down a Gotha into the sea near the North Foreland on July 7th, 1917. The crew of the Armstrong Whitworth were Second Lieutenant F. A. D. Grace and Second Lieutenant G. Murray.
  In Macedonia the F.K.8s of Nos. 17 and 47 Squadrons carried out many useful raids on enemy installations. One of the most notable of these raids was that made on Hudova aerodrome on May 23rd, 1918, when a ton of bombs was dropped. In September, 1918, No. 47 Squadron took part in an action which resembled one fought by No. 1 Squadron, Australian Flying Corps, in Palestine. On exactly the same date, September 21st, 1918, No. 47’s Big Acks and D.H.9s dropped 5,000 lb of high explosives and fired 1,200 rounds of ammunition into the retreating Bulgarian army in the Kosturino Pass, while on the Farweh road the Bristol Fighters of the Australian squadron took a dreadful toll of the retreating Turks caught, like the Bulgarians, in a valley: the Wadi el Far‘a.
  The F.K.8 did not survive long in the R.A.F. after the Armistice, and only eight went on the British Civil Register. In Australia, two F.K.8s pioneered air travel: they were used by the Queensland and Northern Territory Aerial Service Co., Ltd., on the company’s first regular service over the route Charleville-Longreach-Cloncurry which opened on November 2nd, 1922.


SPECIFICATION
  Manufacturers: Sir W. G. Armstrong, Whitworth & Co., Ltd., Gosforth, Newcastle-on-Tyne.
  Other Contractors: Angus Sanderson & Co., Newcastle-on-Tyne.
  Power: Standard: 120 h.p. Beardmore or 160 h.p. Beardmore. Experimental: 150 h.p. R.A.F. 4a and 150 h.p. Lorraine-Dietrich.

Weights (lb) and Performance:
Engine 120 h.p. Beardmore 160 h.p. Beardmore 150 h.p. R.A.F. 4a Lorraine-Dietrich
No. of Trial Report M.32 M.46 M.103 M.89
Date of Trial Report May, 1916 May, 1916 May, 1917 April, 1917
Type of airscrew used on trial L.P.920 - B. & C. 3120 L.P.3020 No. P. 1900
Weight empty 1,682 1,916 1,980 1,936
Military load 105 133 185 185
Crew 320 360 360 360
Fuel and oil 340 402 302 335
Weight loaded 2,447 2,811 2,827 2,816
Maximum speed (m.p.h.) at ground level - 98.4 - -
1,000 ft - - - -
2,000 ft - 97 - -
3,000 ft - - - 92
4,000 ft - 98 - -
5,000 ft - 97 - -
6,000 ft - 96 - -
6,500 ft - - 94 89
8,000 ft 83-5 93 - -
10,000 ft - 88 885 83
12,000 ft - 88 - -
m. s. m. s. m. s. m. s.
Climb to 1,000 ft - - 1 45 1 55 1 55
2,000 ft - - 3 50 - - - -
3,000 ft - - 6 00 - - - -
4,000 ft - - 8 10 - - - -
5,000 ft - - 11 00 - - - -
6,000 ft - - 13 55 - - - -
6,500 ft 19 00 15 25 16 25 16 30
7,000 ft - - - - - - 17 00
8,000 ft - - 20 05 - - - -
9,000 ft - - 23 49 - - - -
10,000 ft 35 00 27 5° 32 00 33 15
11,000 ft - - 32 20 - - 40 55
12,000 ft - - 39 00 46 25 - -
13,000 ft - - 49 00 57 10 - -
Service ceiling (feet) 12,000 13,000 15,000 13,000
Endurance (hours) 3 3 3 4
Tankage :
160 h.p. Beardmore R.A.F. 4a Lorraine-Dietrich
  Petrol 47 1/2 gallons 36 gallons 40 gallons
  Oil 4 3/4 gallons 6 gallons 5 gallons
  Water 6 gallons Nil 1 1/2 gallons
  Dimensions: Span: 43 ft 6 in. Length: (120 h.p. Beardmore) 30 ft 11 in.; (160 h.p. Beardmore) 31 ft; (R.A.F. 4a and Lorraine-Dietrich) 31 ft. Height: (120 h.p. Beardmore) 10 ft 11 in.; (160 h.p. Beardmore) 11ft; (R.A.F. 4a and Lorraine-Dietrich) 11 ft 3 in. Chord: 6 ft 6-7 in. Gap: (160 h.p. Beardmore) 5 ft 10-9 in.; (R.A.F. 4a) 5 ft 6 in.; (Lorraine-Dietrich) 5 ft 7 in. Stagger: (Beardmore and R.A.F. engines) 1 ft 7 3/4 in. at inner struts, 1 ft 7 11/16 in. at outer struts; (Lorraine-Dietrich) 1 ft 4 in. Dihedral: upper 3° 30', lower 2° 30'. Incidence: 2°. Span of tail: 13 ft 6 in. Wheel track: 6 ft. Tyres: 700 X 100 mm. Airscrew diameter: (160 h.p. Beardmore) 9 ft 3-8 in.; (R.A.F.) 9 ft 10 in.; (Lorraine-Dietrich) 8 ft 6 in.
Areas: Wings: 540 sq ft. Ailerons: each 17sq ft, total 68 sq ft. Tailplane:. 31 sq ft. Elevators: 26 sq ft. Fin: 10 sq ft. Rudder: 18 sq ft.
  Armament: One fixed, forward-firing Vickers machine-gun mounted under the cowling and synchronised to fire through the airscrew; one Lewis machine-gun on Scarff ring-mounting on rear cockpit.
  Service Use: Western Front: R.F.C. Squadrons Nos. 2, 8, 10, 35 and 82. H.Q. Communication Squadron. Home Defence: No. 50 Squadron. Macedonia: Part of No. 17 Squadron (the unit had nine F.K.8s on November 11 th, 1918); part of No. 47 Squadron (ten F.K.8s on November nth, 1918). Palestine: Part of No. 142 Squadron (seven F.K.8s on September 19th, 1918). Training: W/T Telegraphist School, Chattis Hill; School of Army Cooperation, Winchester; School of Photography, Maps and Reconnaissance, Farnborough; Air Observers’ Schools at Hythe, New Romney, Manston and Eastchurch; No. 4 School of Aerial Gunnery, Marske; Advanced Air Gunnery School, Lympne; No. 1 Training Depot Squadron, Stamford; No. 31 Training Squadron, Wyton; No. 39 Training Squadron, Narborough.
  Production and Allocation: For the reasons given under this heading in the history of the Armstrong Whitworth F.K.3 precise figures are not available. A total of 1,596 Armstrong Whitworths of both types were delivered to the R.F.C., of which 777 went to the Expeditionary Force in France, 205 to the Middle East Brigade, eight to Home Defence units, and the remainder to Training Units.
  On October 31st, 1918, 694 Armstrong Whitworth F.K.8s were on charge with the R.A.F. Of these, 182 were in France, twenty-one were en route to the Middle East, fifty-six were in Egypt and Palestine, forty-four were in Macedonia, and two were on the North-West Frontier of India. At home, 263 were in store, twenty-one were in transit to or at Aeroplane Repair Depots, thirty-six were at Aircraft Acceptance Parks or with contractors, sixty-six were at training units and various other aerodromes, and three were at experimental stations.
  Serial Numbers: A.2683-A.2732: built by Armstrong Whitworth under Contract No. 87/A/508. A.9980-A.9999. B.201-B.330: built by Armstrong Whitworth under Contract No. 87/A/508. B.3301-B.3400: built by Armstrong Whitworth. B.4120, B.4165, B.4176, B.4200: rebuilds by No. 2 (Northern) Aeroplane Repair Depot. B.5751-B.5850: built by Armstrong Whitworth. G.3507-G.3706: built by Angus Sanderson. C.8401-8650: built by Armstrong Whitworth. D.5001-D.5200: built by Armstrong Whitworth. F.623. F.638, F.4231 (possible batch F.4221-F.4270). F.7384, F.7484. H.4473, H.4561, H.4573, H.4585, H.4612.
  Notes on Individual Machines: Used by No. 2 Squadron: A.9998, B.218, B.246 (Aircraft “13”), B.248, B.258, B.288, B.315. Used by No. 10 Squadron: B.250, B.271, B.324, B.325, B.5772. Used at No. 1 Training Depot Squadron, Stamford: B.4120, B.4165, C.8548, C.8577, D.5075. Other machines: A.2696: fitted with 150 h.p. Lorraine-Dietrich engine No. 1018. B.214 and B.215: fitted with R.A.F. 4a engine. B.252: used at Marske. B.320: No. 50 Squadron. B.3326: used at A.A.G.S. Lympne. C.3648: No. 3 Training Squadron. C.8468: No. 3 Training Squadron. D.5150: became G-EAET. H.4473: became G-EAIC. H.4561: became G-AUCF. H.4573: became G-EAVT. H.4585: became G-EAVQ. H.4612: became G-EAJS.
  Costs:
   Airframe without engine, instruments or armament £1,365 17s. €825 os.
   Engines:
   120 h.p. Beardmore £825 0s
   160 h.p. Beardmore £1,045 0s
   150 h.p. R.A.F. 4a £826 0s.

O.Thetford Aircraft of the Royal Air Force since 1918 (Putnam)

Armstrong Whitworth FK 8

   The FK 8 two-seat Corps reconnaissance aircraft was serving with Nos 2, 8, 10, 35 and 82 Squadrons of the RAF in April 1918, with Nos 17, 47 and 142 Squadrons overseas, and with Nos 39, 50 and 143 Home Defence Squadrons in 1918. Last in service with No 47 Squadron, supporting White Russian Forces in June 1919. Powered by one 160hp Beardmore engine; loaded weight, 2,811lb; span, 43ft 4in; length
31 ft 5in; max speed, 95mph at 6,500ft; initial climb, 330ft/min; endurance,
3hr; service ceiling, 13,000ft.

H.King Armament of British Aircraft (Putnam)

F.K. 8. Superior to the F.K. 3 in power and armament, the F.K. 8 of 1916 was used not only for the duties named for the earlier type but for Home Defence work as a fighter. The pilot had a Vickers gun mounted under the cowling and firing through a port in the nose. This was synchronised by Constantinesco gear, a fact that was proclaimed by the 'box' type generator projecting from the cowling of late-production aircraft. The generator was bracketed to the crankcase so that a gear wheel, fastened to the generator coupling flange, could be driven at twice airscrew speed, by a gear ring bolted to the rear face of the airscrew boss. The rear Lewis gun was on a Scarff ring-mounting, set considerably below the top decking of the fuselage. A twin-gun installation has been identified. Bombs included 20-lb H.E. and 40-lb Phosphorus types.
   Just as the much-maligned B.Es achieved the destruction of Zeppelins, so was the 'Big Ack' credited with bringing down a Gotha. (In the sea off the North Foreland. Crew, 2nd-Lieuts F. A. D. Grace and G. Murray.)

Журнал Flight

Flight, April 3, 1919.

"MILESTONES"

THE ARMSTRONG-WHITWORTH MACHINES

The 160 h.p. Biplane, Type F.K. 8, 1916

   Towards the end of 1916 a larger and improved type of two-seater tractor biplane was designed. This machine, the F.K. 8, was fitted with a 160 h.p. Beardmore engine, and had two machine guns and a wireless installation. It proved a great success, and was built in great quantities, both by the original designers and by other firms. Squadrons of the Royal Flying Corps were equipped with it and used it on all the fighting fronts, its duties including night and day bombing, artillery spotting and reconnaissance, trench fighting, dropping of food to advanced troops, etc. Towards the end of 1917 the output of complete machines of this type in the A.W. works had reached between 80 and 100 machines per month. Construction was continued until July, 1918, when the machine was superseded by the Bristol Fighter. The illustrations will give a good idea of the general fines of the F.K. 8, which, owing to being fitted with a vertical engine, has a certain similarity to German aeroplanes, an impression that is furthered by the fact that there is no centre section, the two halves of the top plane meeting at and being attached to the top of a cabane of steel tubes. The earlier machines were fitted with an oleo type of undercarriage, somewhat similar to that of the F.K. 3, but with the central skid cut short in front of the front under carriage struts. This is the machine shown in the accompanying scale diagrams. One of our photographs shows a somewhat modified form, in which the oleo chassis has been supplanted by one of the ordinary Vee type. There is otherwise so little difference between the two types that we have not thought it necessary to publish scale diagrams of the second type. The outward appearance is the same in both cases, with the exception of the undercarriage. The F.K. 8 is greatly liked by pilots, and is generally considered very safe and strong, while being very easy to fly. If desired for peace purposes, the machine can be adapted to take 120 h.p. Beardmore, 200 Hispano-Suiza, or 250 h.p. Siddeley Puma engines.