O.Tapper Armstrong Whitworth Aircraft since 1913 (Putnam)
F.K.10
In spite of the disappointing performance of the first aircraft, a second, much modified, version was built. This was, indisputably, designated the F.K.10 and it had a more powerful Clerget engine rated at 130 hp. It had a similar wing arrangement but with the span increased by six inches, and, in order to give more room for the crew, the fuselage was both deeper and wider. The tail surfaces were also modified; instead of the fixed tailplane and no upper vertical fin, the second aeroplane had balanced elevators without fixed surfaces and vertical fins above and below the fuselage supporting a conventional, if rather small, rudder. In an attempt to overcome the undercarriage weakness of the previous aircraft, the longerons, from the undercarriage struts forward, were strengthened with plywood, but the structure was still not strong enough and it was reported that the diagonal struts within the fuselage, designed to take the compression loads from the undercarriage, were bent when the aircraft was delivered for official trials.
These trials were undertaken in March 1917, and the performance seems to have been slightly inferior to that of the lower-powered version. This may have been due to the fatter fuselage, but it is equally possible that the difference between the two aircraft arose because of variations in piloting skill and because of the somewhat imprecise methods of performance measurement then in use. The test pilot reported that the machine handled well, with good controllability and with very little tendency to spin. The take-off and landing distance was measured as 80 yards. As might be expected with an all-moving tailplane, the aircraft was somewhat unstable longitudinally, and the pilot noted that the controls could not, therefore, be left alone. In other respects the aircraft was considered easy to fly. Minor criticisms were that the windscreen was inefficient and that it was necessary to remove the engine cowling in order to replenish the oil tank. Like its predecessor, the second aircraft was reported as having a performance below that specified.
In view of the poor performance, an order for fifty F.K.10s which had been placed with Angus Sanderson and Co was cancelled in March 1917, and the serial numbers A8950 to A8999 set aside for this batch were reallocated. However, small batches of the F.K.10 were produced by Armstrong Whitworth, Angus Sanderson and the Phoenix Dynamo Manufacturing Co. Most of the production aircraft had the 130 hp Clerget engine, but at least one of those built by Armstrong Whitworth was powered by a Le Rhone engine of 110 hp. There is some uncertainty about the numbers of quadruplanes actually built: two, with the serial numbers A5212 and A5213, were ordered from Armstrong Whitworth, one of which may have been the original F.K.9, and a further five, numbered 83996 to 84000, were ordered from Angus Sanderson, but it is not known whether all were delivered. Three more, N511, N512 and N514, were built for the Royal Naval Air Service, the first two by Phoenix Dynamo and the third by Armstrong Whitworth. The missing number, N513, was originally allotted to an Angus Sanderson F.K.10 which was cancelled, and there is some evidence that this number was subsequently re-allocated to an Armstrong Whitworth biplane, presumably an F.K.8, with a Sunbeam engine: this aircraft is said to have force-landed near Beverley on 7 April, 1917, while en route from Newcastle to Martlesham Heath.
In spite of the official test reports, which indicated that the aircraft at least handled reasonably well, pilots seem to have been suspicious of the F.K.10 from the start. It certainly had a rather daunting appearance, and no doubt this, coupled with the maintenance problems, seems to have resulted in the few available aircraft being little used. The two RNAS machines, N511 and N514, were reported to be at Manston aerodrome in April and May 1917, but they were apparently considered to be unsafe and by the late summer had been grounded. The RFC aircraft may have lasted rather longer, but they, too, were never taken seriously and eventually, in July 1917, were handed over to the technical department for use as ground targets. Thus, the F.K.10 faded from the scene with, apparently, few regrets.
That Koolhoven's interest in the multiplane arrangement was not altogether damped by the failure of his three- and four-winged prodigies is evident from drawings that exist showing a design, known perhaps as the F.K.11, which had no less than fifteen narrow wings, each about 18-inches wide, attached to an F.K.10 fuselage. This project was never built, but the 'Venetian blind' arrangement of aerofoils had been tried before. One of the first to toy with the idea was Horatio Phillips, who tried out an apparatus with forty slats (if contemporary drawings are to be believed) on a circular track at Harrow in 1893. After the 1914--18 war the idea was revived by H. G. Leigh who, in collaboration with Bert Hinkler of the Avro company, fitted a modified form of the slatted-wing arrangement to the fuselage of an Avro Baby.
F.K.10
Dimensions: Span 28 ft 3 in (8.61 m); length 25 ft 6 in (7.77 m); height 11 ft 6 in (3.50 m); wing area 361 sq ft(33.54 sq m).
F.K.10
130 hp Clerget
Max weight: 2,019lb (916kg)
Empty weight: 1,236lb (561kg)
Max speed
Sea level: -
3,000ft (914 m): 95 mph (153km/hr)
6,500ft (1,981 m): 84 mph (135km/hr)
10,000 ft (3,048 m): 74 mph (119km/hr)
Climb to
6,000ft (1,829 m): -
6,500ft (1,981 m): 15.8min
10,000ft (3,048 m): 37.2min
Service ceiling: 10,000ft (3.048 m)
Endurance: 2 1/2 hr
Показать полностью
P.Lewis The British Fighter since 1912 (Putnam)
In the unending quest for fighter supremacy designers in Britain explored most layouts and, in 1916, the Armstrong Whitworth designer F. Koolhoven was responsible for a two-seat fighter reconnaissance quadruplane which, despite the complexity of its four wings, struts and pair of cockpits was, none the less, a clean and pleasing machine, especially in its final form. The prototype used the 110 h.p. Clerget engine while the modified later version, of which a few were built, had the 130 h.p. Clerget. Tests showed that the F.K.10 was not a particularly successful machine and it remained simply one of the more unusual designs of the 1914-18 War.
<...>
Following the F.K.10 quadruplane design Armstrong Whitworth investigated an extraordinary development by Koolhoven to be known as the F.K.11 which was intended to be borne on a set of wings reminiscent of those tested by Horatio Phillips a decade before. The F.K.11’s small-chord mainplanes would have numbered fifteen, set with pronounced stagger on the same style of fuselage as that used on the F.K.10.
The F.K.11 was not proceeded.
Показать полностью
F.Mason The British Fighter since 1912 (Putnam)
Armstrong Whitworth F.K. 10
Possibly originally undertaken as a design exercise to investigate the potential of the quadruplane configuration, Frederick Koolhoven’s F.K.10 attracted the interest of the Services as a possible fighter. A prototype was built during the late summer of 1916, emerging as a lanky two-seater powered by a 110hp Clerget engine and featuring a slim, angular fuselage in which the pilot’s cockpit was located forward of the wings, and an observer’s cockpit aft of them. The wings, of only 3ft 7in chord, spanned 27ft 10in, and were rigged with a total stagger of 4ft 3in. The tail comprised a rather crude horn-balanced rudder with fixed fin below the fuselage, fixed tailplane and unbalanced elevator. The undercarriage consisted of single faired struts on each side, with the spreader bar heavily cable-braced between its extremities and the lower longerons. Single interplane and cabane I-struts were employed, and the second from top wing possessed no centre section so as to leave the crew’s field of view less obstructed. Ailerons were fitted on all wings. A single synchronized Vickers gun was provided for the pilot and was mounted on the aircraft’s centreline over the engine cowling, the observer’s cockpit being equipped with a mounting for a Lewis gun.
A total of three prototypes is believed to have been built by Armstrong Whitworth, after which the War Office ordered five production aircraft from Angus Sanderson of Newcastle, and the Admiralty ordered three from the Phoenix Dynamo company of Bradford, though it is not known whether all were built. Most were fitted with 130hp Clergets.
The production F.K.10s were rather more elegantly styled than the original prototype, with larger fuselage section and tidied-up tail surfaces. One of the RFC machines was flown by the Training Unit at Gosport, and the first RNAS aircraft, N511, underwent its Service trials at Boroughbridge in April 1917; another of the naval aircraft was completed as a bomber with racks for light bombs.
Type: Single-engine, two-seat, single-bay quadruplane fighter.
Manufacturers: Sir W G Armstrong, Whitworth & Co Ltd, Newcastle-upon-Tyne; The Phoenix Dynamo Manufacturing Co Ltd, Bradford; Angus Sanderson & Co, Newcastle-upon-Tyne.
Powerplant: One 110hp Clerget engine; also 130hp Clerget; 110hp Le Rhone.
Dimensions: Span, 27ft 10in; length, 22ft 3in; height, 11ft 6in; wing area, 390.4 sq ft.
Weights: (130hp Clerget). Tare, 1,236lb; all-up, 2,019lb.
Performance: (130hp Clerget). Max speed, approx 90 mph at sea level; climb to 10,000ft, 37 min 10 sec; service ceiling, 10,000ft; endurance, 2 1/2 hr.
Armament: One synchronized 0.303in Vickers machine gun on nose, and one 0.303in Lewis gun on real' cockpit mounting.
Prototypes: Believed three, A5212-A5214 (built by Armstrong, Whitworth).
Production: Total of eight ordered (B3996-B4000 for RFC, built by Angus Sanderson; N511, N512 and N514 built by Phoenix Dynamo).
Summary of Service: Single examples flown by the RFC at Gosport, and by the RNAS at Mansion, both probably in 1917.
Показать полностью
W.Green, G.Swanborough The Complete Book of Fighters
ARMSTRONG WHITWORTH F.K.10 UK
Derived from the F.K.9, but embodying considerable redesign, the F.K.10 two-seat fighter-reconnaissance quadruplane retained virtually no more than the basic wing structure of its immediate predecessor. A production contract for 50 F.K.10s was given to Angus Sanderson & Company of Newcastle-on-Tyne on 30 December 1916 on behalf of the RFC, but only five aircraft were destined to be completed before the contract was cancelled. Three were ordered for the RNAS, two of these from the Phoenix Dynamo Manufacturing Company and one from Armstrong Whitworth, these eventually being completed and tested. The F.K.10 was normally powered by a 130 hp Clerget 9B rotary, but at least one was flown with a 110 hp Le Rhone, and armament comprised one fixed 0.303-in (7,7-mm) Vickers gun and one free 0.303-in (7,7-mm) Lewis.
Max speed, 84 mph (135 km/h) at 6,500 ft (1980 m), 74 mph (119 km/h) at 10,000 ft (3 050m).
Time to 6,500 ft (1980 m), 15.85 min.
Endurance, 2.5 hrs. Empty weight, 1,236 lb (560 kg).
Loaded weight, 2,019 lb (916 kg).
Span, 27 ft 10 in (8,48 m).
Length, 22 ft 3 in (6,78 m).
Height, 11 ft 6 in (3,50 m).
Wing area, 390.4 sq ft (36,27 m2).
Показать полностью
J.Bruce British Aeroplanes 1914-1918 (Putnam)
Armstrong Whitworth F.K. 10
IT has been said, not without some truth, that almost every variation of the aeroplane form of aircraft was tried out during the 1914-18 war by one or other of the combatants. Monoplanes, biplanes and triplanes appeared in astonishing variety and profusion, and the quadruplane form was built and flown in Britain and Germany.
In Britain, at least four quadruplane types were built. The Supermarine concern built two large twin-engined quadruplanes, the P.B.29 of 1915 and the Night Hawk of 1916; the little Wight quadruplane single-seat fighter appeared in three slightly different forms; and the two-seat fighter-reconnaissance type was represented by the Armstrong Whitworth F.K.10. On the German side, at least two single-seat fighter quadruplanes were built; namely the Naglo with the 160 h.p. Benz, and the Euler with an Oberursel rotary engine.
The Armstrong Whitworth F.K.10 provided an excellent example of the striking originality of thought possessed by Frederick Koolhoven. The prototype had a slender fuselage, a fixed tailplane, and an ugly horn-balanced rudder; the engine was the 110 h.p. Clerget. It is doubtful whether any military equipment was fitted to this machine, and it seems probable that it may have been built solely to test the quadruplane wing arrangement.
The later prototypes had the same wing arrangement as the first, but the fuselage was more portly and the tail unit had been re-designed. There was now no fixed tailplane but only a balanced elevator reminiscent of the Morane-Saulnier monoplanes, and the vertical tail surfaces were of more pleasing form with approximately equal areas of fin above and below the fuselage. The 130 h.p. Clerget replaced the 110 h.p. engine of the first machine, but at least one F.K.10 had a 110 h.p. Le Rhone.
The pilot, from his cockpit ahead of the wings, had a remarkably good view in almost all forward and upward directions. This was one of the principal reasons for the adoption of the quadruplane layout, and good manoeuvrability was probably hoped for as a result of the use of four ailerons on each side and the compression of the wing area into a short span.
Armament was fitted to these F.K.10s, and consisted of a fixed synchronised Vickers gun for the pilot and a stripped Lewis on a rocking-post mounting for the observer.
A small batch of F.K.10s were ordered for the R.F.C. from Angus Sanderson & Co., presumably owing to Armstrong Whitworth’s pre-occupation with production of the F.K.8.
The R.N.A.S. were also interested in the type and ordered a few from other contractors. Two machines, N.511 and N.512, were built by the Phoenix Dynamo Manufacturing Co., Ltd., in 1917. The first was intended to be a two-seat fighter, for which purpose a Scarff ring-mounting was provided for the observer’s Lewis gun; the second machine, N.512, was built as a bomber. N.511 underwent its trials at Boroughbridge on April 26th, 1917.
The Phoenix-built F.K.10s differed in detail from the machines built by Armstrong Whitworth. They had horse-shoe cowlings instead of full circular; the coaming in front of the pilot’s cockpit was fuller and no windscreen was fitted; and small end-plates were fitted at the inboard ends of the bottom mainplanes.
All the F.K.10s were characterised by the heavily staggered wings connected by a single “plank” interplane strut and similar centre section struts, and by the peculiar single-strut undercarriage braced in three planes by cross-wires. The resulting structure did not look particularly strong, but presumably it worked well enough.
The R.F.C. flew an F.K.10 at Gosport, and the R.N.A.S. quadruplanes were flown at Manston; but the F.K.10 was not a good aeroplane, and production was not undertaken. The machine must have been sensitive on the elevators in the same way as the Moranes were, and it suffered from a form of wing flutter. The type was ultimately abandoned and four F.K.10s were scrapped at Manston in 1917.
A remarkable development was projected as the F.K.11. It was to consist of the fuselage of an F.K.10 fitted with fifteen narrow-chord mainplanes, heavily staggered and mounted close together.
SPECIFICATION
Manufacturers: Sir W. G. Armstrong, Whitworth & Co., Ltd., Gosforth, Newcastle-on-Tyne.
Other Contractors: The Phoenix Dynamo Manufacturing Co., Ltd., Bradford; Angus Sanderson & Co., Newcastle-on-Tyne.
Power: 110 h.p. Clerget; 130 h.p. Clerget; 110 h.p. Le Rhone.
Dimensions: Span: 27 ft 10 in. Length: 22 ft 3 in. Height: 11 ft 6 in. Chord: 3 ft 7 in. Gap: 2 ft 8 in. Stagger: 1 ft 5 in. Dihedral: 1° 30'. Incidence: 3°.
Areas: Wings: top 102-6 sq ft, second 92-6 sq ft, third 92-6 sq ft, bottom 102-6 sq ft; total 390-4 sq ft. Ailerons: each 8-4 sq ft, total 67-2 sq ft. Elevators: 16 sq ft. Fin: 1-9 sq ft. Rudder: 8 sq ft.
Weights (lb) and Performance:
Engine 110 h.p. Clerget 130 h.p. Clerget Manufacturer’s figures for 130 h.p.
No. of Trial Report M.77 M.82 -
Date of Trial Report Dec. 1916 Mar., 1917 -
Type of airscrew used on trial L.P.710C L.P.710C -
Weight empty 1,226 1,236 1,143
Military load 160 160 -
Crew 360 360 -
Fuel and oil 292 263 -
Weight loaded 2,038 2,019 1,804
Maximum speed (m.p.h.)
at ground level - - 105
6,500 ft 94 84 -
10,000 ft 87-5 74 99
m. s. m. s. m. s.
Climb to
6,500 ft 14 20 15 50 - -
10,000 ft 23 35 37 10 17 00
Service ceiling (feet) 13,000 10,000 -
Endurance (hours) 3 2 1/2 -
Armament: One fixed forward-firing Vickers machine-gun mounted centrally above the engine cowling and synchronised to fire through the airscrew; one Lewis machine-gun on rocking-post mounting or Scarff ring-mounting in rear cockpit.
Service Use: Flown by the R.F.C. at Gosport and by the R.N.A.S. at Manston.
Production and Allocation: Serial numbers were allotted for at least eleven Armstrong Whitworth F.K.10s, but all may not have been completed. One was delivered to the R.F.C. Training Unit at Gosport in 1916.
Serial Numbers: A.5212-A.5214: built by Armstrong Whitworth under Contract No. 87/A/1254. B.3996-B.4000: built by Angus Sanderson. N.511-N.512: built by Phoenix Dynamo Mfg. Co. under Contract No. C.P.135178/16. N.514: built under Contract No. C.P.100565/16.
Показать полностью
O.Thetford British Naval Aircraft since 1912 (Putnam)
ARMSTRONG WHITWORTH F.K.10
Four of these unconventional two-seat quadruplanes were built for the RNAS in 1917, serialled N511-514. They were built under licence by the Phoenix Dynamo Manufacturing Company of Bradford. The first naval F.K.10 was equipped as a two-seat fighter and the second as a bomber. One 130 hp Clerget engine. Loaded weight, 2,019 lb. Maximum speed, 84 mph at 6,500 ft. Service ceiling, 10,000 ft. Span, 27 ft 10 in. Length, 22 ft 3 in.
Показать полностью
H.King Armament of British Aircraft (Putnam)
F.K. 10. Several examples of this two-seat 'fighter-reconnaissance# quadruplane were built during 1916-17. The pilot's fixed Vickers gun was on the centre line, with faired breech casing, and the observer's Lewis gun was generally on a rocking-pillar mounting, though at least one specimen of the F.K. 10 had a Scarff ring-mounting.
Показать полностью
Jane's All The World Aircraft 1919
Derived from the F.K.9 but embodying considerable redesign, the F.K.10 two-seat fighter-reconnaissance quadruplane retained virtually no more than the basic wing structure of its immediate predecessor. A production contract for 50 F.K.10s was given to Angus Sanderson & Company of Newcastle-on-Tyne on 30 December 1916 on behalf of the RFC but only five of these were destined to be completed before the contract was cancelled, and three were ordered for the RNAS, two of these from the Phoenix Dynamo Manufacturing Company and one from Armstrong Whitworth, these eventually being completed and tested. The F.K.10 was normally powered by a 130 hp Clerget 9B rotary, but at least one was flown with a 110 hp Le Rhone, and armament comprised one fixed 0-303-in (7,7-mm) Vickers gun and one free 0-303-in (7,7-mm) Lewis.
Max speed, 84 mph (135 km/h) at 6,500 ft (1 980 m),
74 mph (119 km/h) at 10,000 ft (3 050 m).
Time to 6,500 ft (1 980 m), 15 min 50 sec.
Endurance, 2 hr 30 min.
Empty weight, 1,236 lb (560 kg).
Loaded weight, 2,019 lb (916 kg).
Span, 27 ft 10 in (8,48 m).
Length, 22 ft 3 in (6,78 m).
Height, 11 ft 6 in (3,50 m).
Wing area, 390-4 sq ft (36,27 m2).
Показать полностью
Журнал Flight
Flight, April 3, 1919.
"MILESTONES"
THE ARMSTRONG-WHITWORTH MACHINES
The A.W. Quadruplane, Type F.K. 10, 1917
Next in the series comes the A.W. "Quad," which was first tested some time in 1917. By that time the single-seater fighting scouts were being employed in great quantities, and the question of good visibility was one of paramount importance, a pilot whose machine obscured the view to a great extent in any direction being at a considerable disadvantage. This question of visibility was attempted to be solved in the A.W. "Quad," in which, as will be seen from the accompanying illustrations, the stagger was very pronounced, while the second plane passed across some little distance above the top of the fuselage, the third and fourth planes passing through and under the body respectively, and obstructing, owing to their narrow chord, the view to a small extent only. When this machine first appeared the triplane had been tried with fair success, but the multiplane was somewhat of a dark horse, as regards its aerodynamic properties. From the table of performance it will be seen that the speed and climb of the A.W. Quad, were, if anything, inferior to those of contemporaneous triplanes with the same engines, while being a good way behind small biplanes with engines of 130 h.p. It, therefore, appears that quadruplanes do not give so good results as biplanes or triplanes as regards performance, and we understand that they are not particularly nice to fly. It will be noticed that on the A.W. Quad, there is no fixed tail plane. This is probably in order to render the elevators as effective as possible, a necessary precaution on a quadruplane with its comparatively great height over the aerofoils.
Показать полностью
