A.D. Flying-boat (1915/17)

   The A.D. Flying-Boat was built to a design of the Air Department of the Admiralty as a patrol and reconnaissance machine to Specification N.2A. The design team consisted of Harold Yendall, Harold Bolas, Clifford Tinson, and Lt.-Col. Linton Hope, the latter responsible for the construction layout of the monocoque hull. Construction of two prototypes commenced in October 1915, the serials allocated being No. 1412 and No. 1413, contracts having been placed with Pemberton-Billing, Ltd, for the superstructure, and with May, Harden and May, for the hulls. A two-seater biplane, the A.D. boat was of mixed wooden construction, fabric covered and wire braced, with the mainplanes arranged to fold forward for shipboard stowage. A biplane tail unit was fitted, with twin fins and rudders, the lower plane made as a watertight unit as it was awash during taxying. The upper tailplane had an inverted aerofoil and a negative angle of incidence, to prevent a tail-heavy trim change when the engine was throttled back. In its original form, the first prototype, No. 1412, was powered by a pusher Sunbeam Nubian engine of 150 h.p. driving a 10-foot diameter four-bladed propeller, and with this power unit No. 1412 underwent its first trials in the summer of 1916. The results were not promising, for the machine suffered from porpoising and poor rudder control, and the design weight had already been exceeded by 500 pounds. At the suggestion of Sqdn. Comm. Travers, the step was moved 2 feet aft to improve water handling, but this had little effect, and as a result of porpoising trials held at Southampton in August 1916, by a Seaplane Research Team under G. S. Baker, o.b.e., a trials report stated that the machine was unsatisfactory, further trials being cancelled by the Air Department. Work continued on the machine throughout the winter of 1916, the most obvious changes being the installation of a 200 h.p. Hispano-Suiza engine, shorter span ailerons, and greatly enlarged wing-tip floats. In this form, No. 1412 was tested at Southampton on 12 and 15 March, 1917, and performed satisfactorily. Production was soon under way, and on 5 September, 1917, the first production machine, N1520, was the subject of a satisfactory trials report from the Isle of Grain.
   However, engine trouble proved to be the main reason for the A.D. boat’s eventual downfall, apart from the fact that it was not an easy machine to handle both in water manoeuvring and on take-off. The geared Hispano- Suiza engine, French-built, was vibrating and failing in flight, the same faults that were giving cause for anxiety with the S.E.5a. In July 1917, No. 1412 was fitted with a 150 h.p. direct-drive Hispano-Suiza engine in an attempt to remedy the situation, but with this power unit the performance was impaired. February 1918 saw No. 1412 fitted with a 200 h.p. Sunbeam Arab, but this engine performed no better in the A.D. boat than in other aircraft to which it had been fitted, and it, too, was shelved. In mid-1918, a production machine, N1525, was fitted with a Wolseley Python engine of 211 h.p., and later with a 200 h.p. Wolseley Viper, neither installation being satisfactory. Most of the A.D. boats produced other than those mentioned went into storage, with the exception of N1719 and N1712 which were allocated to the Isle of Grain for experimental purposes. In 1921, Harry Busteed and G. Bentley Dacre, both by now senior R.A.F. officers, used N1719 for successful hydrofoil experiments. The total A.D. boat production consisted of the two prototypes and twenty-seven production machines, and the type was declared obsolete in the late autumn of 1918. In June 1919, ten A.D. boats were re-purchased by Supermarines, lately Pemberton-Billing, Ltd, and after fitment of a 160 h.p. Beardmore engine and some modification became civilianised as the Supermarine Channel, the first Channel being a conversion of N1529. Further purchases of A.D. boats were made later, to a total of some nineteen machines in all.


SPECIFICATION

   Power Plant:
   150 h.p. Sunbeam Nubian
   200 h.p. Hispano-Suiza
   150 h.p. Hispano-Suiza
   200 h.p. Wolseley Python
   200 h.p. Wolseley Viper
   200 h.p. Sunbeam Arab
   Span: 50 feet 4 inches. Folded: 14 feet
   Length: 30 feet 7 inches. Folded: 42 feet 3 inches
   Weight Loaded:
   2,880 pounds (No. 1412) (200 h.p. Hispano-Suiza)
   3,388 pounds (N1525) (200 h.p. Wolseley Python)
   Total Area: 479 square feet
   Max. Speed: 87,5 - 100 m.p.h., depending upon loaded weight and engine installed
   Endurance: 3,5 - 5 hours, as above
   Armament:
   Production - one .303-inch Lewis gun
   Type 54A wireless set fitted

Blackburn N.IB (1918)

   Designed to the same Air Board Specification as the Supermarine Baby, work commenced on the Blackburn N.1B at the Leeds factory in mid-1918. The hull, of Linton Hope design, was similar to the Baby, being of the usual monocoque construction with external side fins, which extended aft to the main step amidships, and having a small auxiliary step mid-way towards the stern. The bows were longer and more pointed than those of the Baby, however, and the rear part of the hull had a distinctive upward curve towards the stern. The complete machine was to be a single-seat single-bay biplane, the lower mainplane mounted on the hull top and braced from the main step by Vee-struts. A 200 h.p. Hispano-Suiza pusher engine, driving a two-bladed propeller was to be mounted on struts high up in the centre section. The tail unit design was of biplane layout, with twin rudders, the upper plane of inverted camber as on the A.D. Boat and the Supermarine Baby. Large wingtip floats were to be attached directly to the lower wing undersurface. Some difficulties were encountered during hull construction; the American elmwood required was late in delivery, and eventually other woods had to be be used. The hull was then found to require extra stiffening, and eventually, although good progress was made, the coming of the Armistice brought the development to a halt. The completed hull was put into storage. In 1923, an inspection found it still in good condition, and fitted with a new engine and flight structure it was entered for the Schneider Trophy as the Blackburn Pellet.


SPECIFICATION

   Power Plant: One 200 h.p. Hispano-Suiza
   Span: 34 feet 10 inches
   Length: 28 feet 3 1/2 inches
   Weight Loaded (estimated): 2,390 pounds
   Total Area: 376 square feet
   Max. Speed (estimated): 114 m.p.h.
   Endurance (estimated): 3 hours
   Armament: One free-mounted Lewis gun
   Serials Allotted: N56-N58

Burney X.1, X.2, and X.3 (1911-1913)

   In the summer of 1911, Lieut. Charles Burney, r.n. (later Sir Charles Burney, of Airship R.100 fame) obtained Admiralty sanction for the British and Colonial Aeroplane Company to undertake design of a ship-borne aircraft employing hydrofoils to achieve take-off and landing on rough water. Burney had studied the works of the Italian pioneers Foriannini and Guidoni on the application of hydrofoils to improve the performance of fast motor boats, and was convinced that the hydrofoil had applications to the design of marine aircraft. Experiments began in the autumn of 1911, when Burney co-operated with Howard Pixton in a series of over-water flights from Hayling Island in a Bristol Boxkite equipped with flotation bags. In December, Frank Barnwell was appointed experimental designer for the project, taking up his duties in a private house at Filton which became known as ‘X’ Department, and was shrouded in secrecy.

X.1

   In collaboration with Burney, Barnwell produced the first design study, known as the X.1 This was a modification of the Gordon England biplane (G.E.1). The original 50 h.p. Clerget engine was to be replaced by a more powerful eight-cylinder E.N.V., driving a shaft between the cylinder banks with a Hele-Shaw clutch at each end. The front clutch was to drive a normal tractor propeller, while the rear clutch drove a bevel gearbox from which two shafts extended downwards inside tubular undercarriage legs fitted with groups of hydrofoils. At the bottom of each leg there was a further bevel drive to a water propeller. A third strut, also equipped with hydrofoils, was fitted under the rear fuselage. These grouped hydrofoils were called ‘hydropeds’. The idea was that, when driven by the water propellers, the craft would rise out of the water on the hydropeds until there was sufficient clearance for the flight propeller to be clutched in, and take-off would then be made. While at rest on the water, the aircraft would have floated on five torpedo-shaped air bags, which were not, however, intended to act as planing surfaces.
   In January 1912, Barnwell, now joined by an assistant, Clifford Tinson, proposed that the biplane arrangement should give way to a monoplane wing of startling ingenuity. This was to be pneumatic, formed of eight span-wise air bags arranged to fit into a suitable wing section and capable of inflation to high pressure. The aerofoil profile would be maintained by flat spruce strips, forming ribs, and hinged at leading and trailing edges, with bicycle spokes acting as tension members between the upper and lower strips. Externally braced, the wing was to be fitted with ailerons, also inflatable. Storage would be simplified by deflation of the entire wing structure. Unfortunately, the rubberised canvas of the day proved to be too weak and too heavy for the demands made upon it, and the idea had to be shelved.

X.2

   In February 1912, a new design, the X.2, was produced, and construction commenced. In this, the flotation bags were eliminated, and the fuselage was built as a proper hull, planked with mahogany and covered with varnished sailcloth, a normal monoplane wing being fitted. This craft, Works No. 92, was built in the experimental shop at Filton, and equipped with side-by-side dual controls. The clutches and hydropeds developed for X.1 were used, but the engine was a water-cooled radial Canton-Unne of 80 h.p. On 9 May, 1912, X.2 was put aboard the lighter Sarah at Avonmouth, and taken to Dale, near Milford Haven. After overcoming initial leakages, taxying under power from the water screws was attempted, and later the craft was towed behind a torpedo boat. Despite modification, it proved impossible to prevent the machine from heeling over when the water screws were clutched in during towing. Eventually, in September 1912, it was decided to rely upon towing for the preliminary air tests. The engine was replaced by 500 lb of ballast, and on 21 September, X.2 was towed into a 30-knot wind with Lieut. G. Bentley Dacre, R.N., in the cockpit. At an airspeed of 42 knots, it rose clear of the water in a climbing attitude, but premature release by the towline party caused it to stall and crash, though without injury to Dacre.

X.3

   The Admiralty agreed to continue the experiments, and work commenced on an improved design, the X.3. The engine fitted was a 200 h.p. Canton-Unne, and although similar to X.2 in most respects, this machine had wingtip floats with small hydrofoils under them. The hull frame, constructed at Filton, was then transported to Saunders at Cowes for covering with their patent ‘Consuta’ sewn plywood. To overcome torque reaction, the water screws were mounted back to back on a central pylon, so that they rotated in opposite directions. This machine, Works No. 159, was shipped to Dale in August 1913, and towing tests were very satisfactory. The nose dipped when the flight propeller was clutched in, - so to overcome this Barnwell designed an elevator, located in front of the mainplane and linked to the propeller clutch control. However, before the device could be fitted, X.3 came to grief while taxying, when it was wrecked on a sandbank.

   With this mishap, the experiments came to an end, but the principle of the hydrofoil was employed by Burney in his invention of the paravane for minesweeping. In 1930, the Piaggio Pegna P.C.7 racing seaplane project utilised an almost identical layout to X.3, but also was a failure due to mechanical problems with the water screw.


SPECIFICATION

   Power Plant:
   X.1 (project) - 60 h.p. E.N.V. Vee-eight engine
   X.2 - 80 h.p. Canton-Unne water-cooled radial engine
   X.3 - 200 h.p. Canton-Unne engine
   Span:
   X.1 - 34 feet
   X.2 - 55 feet 9 inches
   X.3 - 57 feet 10 inches
   Length:
   X.1 - 30 feet
   X.2 - 30 feet 8 inches
   X.3 - 36 feet 8 inches
   Wing Area:
   X.1 - 325 square feet
   X.2 - 480 square feet
   X.3 - 500 square feet

Porte/Felixstowe F.1 (1915)

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   Early in 1915, Porte was stationed at Felixstowe, and flew the H.4 operationally, being therefore well qualified to understand its shortcomings. In the spring of 1915, he began a series of experiments, officially approved, with the aim of producing a seaworthy and operationally useful flying-boat. This involved re-designing and fitting of completely new hulls to four H.4s, Nos. 950, 1230, 3545, and 3569, culminating in the modification of H.4 No. 3580 with a new hull incorporating all the structural and hydrodynamic features developed to high efficiency in the preceding experiments. This hull, built at Felixstowe, was named the Porte 1, the complete machine being designated F.1, the first of the line of Felixstowe ‘F’ boats. The wings and tail unit of the F.1 were standard H.4 components, but its chief interest lay in the hull construction, which differed little from the fuselages of most contemporary landplanes. Of strong cross-braced box girder configuration, it was fitted with an external vee-shaped planing bottom and long side fins. Overall, the hull was 36 feet 2 inches in length, with a maximum beam of 8 feet, and unlike its predecessors, possessed open cockpits. Originally the hull had only one step, but performance requirements were not met, so a second and finally a third step were added. The machine was powered by two 150 h.p. Hispano-Suiza engines driving tractor propellers.


SPECIFICATION

   Power Plant:
   F.1 - Two 150 h.p. Hispano-Suiza
   H.4 - Two 90 h.p. Curtiss, or two 100 h.p. Anzani
   Span: F.1 and H.4 - 72 feet
   Length:
   F.1 - 39 feet 2 inches
   H.4 - 35 feet
   Weight Loaded:
   H.4 - 4,983 pounds
   Total Area: F.1 and H.4 - 842 square feet
   Max. Speed:
   F.1 - 85 m.p.h.
   H.4 - 75 m.p.h.
   Endurance: Not available
   Armament: F.1 and H.4 - One or two Lewis guns, light bombs only

Porte/Felixstowe F.2 and F.2A (1917)

   As a result of the shortcomings of the Curtiss H.4 regarding long-range patrol work, Porte requested Glenn Curtiss to develop a larger flying-boat with greater range and load-carrying capacity, and an order for fifty such machines was placed in 1915, the first being delivered in July 1916. This was the Curtiss H.8, or ‘Large America’, powered by two 160 h.p. Curtiss engines. These engines proved to be unsatisfactory, however, and Porte had them replaced by two 250 h.p. Rolls-Royce units, the modified machines being designated Curtiss H.12. They performed quite well, but suffered from weak, unseaworthy hulls, and poor fields of fire for the defensive armament. Encouraged by the excellent results obtained for the Porte 1 hull, Porte decided to redesign the hull of the H. 12, ably assisted by his Chief Technical Officer, Lieut, (later Major) J. D. Rennie. The new hull used the same construction method as the Porte 1 and measured 42 feet 2 inches from bow to stern, with two steps, and side fins 30 feet in length. Fitted with the mainplanes of an H.12, two 250 h.p. Rolls-Royce engines and a new tail unit, the machine, serialled No. 8650, was designated F.2 and proved vastly superior in performance to the standard H.12, taking off smoothly and easily at a loaded weight of 10,500 pounds. After some structural modifications were made in the light of operational experience, quantity production was authorised, the production version designated F.2A. Fitted with the more powerful Marks of the Rolls-Royce Eagle, the F.2A had a range and endurance more than adequate for defensive and offensive patrols, and a formidable armament consisting of two 230-pound bombs and up to five Lewis guns with excellent fields of fire. The fuel system, however, gave a lot of trouble, mainly due to its layout. A 409-gallon tank situated in the hull fed a 26-gallon gravity tank in the upper mainplane centre section by means of wind-driven pumps, the fuel then passing to the engines by gravity. Blocked pipes and filters, and fuel pump failures caused many forced alightings, and a contemporary report stated that ‘our real enemy is our own petrol pipes’. This situation led to the adoption of bizarre colour schemes for F.2A hulls, using red, white, and yellow paint, so that stricken machines could be readily spotted and towed home. Production F.2As began to appear late in 1917, a sub-contract having been arranged with Short Brothers, of Eastchurch. These machines had a two-stepped hull, only slightly differing from that of the F.2. In the bows, the front gunner’s cockpit was equipped with twin Lewis guns on a Scarff ring-mounting, while the rear gunner was positioned aft of the lower mainplane with similar armament. Some aircraft also had single guns, fired from side-hatches in the hull. The first and second pilots, the latter acting as front gunner, were partially enclosed in a glazed cabin, although this was often removed to improve visibility and performance. Engine control was simplified by the employment of an engineer-gunner, positioned in an internal compartment and controlling engine starting and inflight temperatures. The fourth crew member was usually a rigger-gunner. This crew arrangement tended to make the boats less dependent on their bases for servicing and minor repairs, and was standard in all large R.N.A.S. flying-boats. The F.2A power units were two Rolls-Royce Eagle VI Ils, developing 346 h.p. at 1,800 r.p.m. and driving four-bladed tractor propellers, the revolutions of which were reduced to 1,080 r.p.m. by epicyclic gearing. Some of the early F.2As had fabric decking to their hulls, but the ravages of wind and weather soon indicated its weakness and later machines had plywood decking. Production was greatly facilitated by the fact that the relatively simple hull construction did not call for highly skilled labour, and also by the availability of H.12 components, but demands for Rolls-Royce engines so far exceeded the supply that the total number of F.2As on charge never reached official requirements. To offset this situation several H.12s were rebuilt with Porte hulls and F.2A tail units, these modifications rendering them indistinguishable from F.2As.
   Together, the F.2As and H.12s rendered great service in the critical year of 1917, when U-boat warfare was at its height. The first success came on 20 May, when the H.12 commanded by Fit. Sub-Lieut. Morrish destroyed submarine UC-36, and by the end of the year the flying-boats had sighted sixty-seven U-boats and had attacked forty-four. The Zeppelins, too, came in for attention, and on 14 May, 1917, L.22 fell to the guns of H.12 No. 8666, captained by Fit. Lieut. Galpin. In June, L.43 was destroyed by H.12 No. 8677, and a year later an F.2A from Killingholme, flown by Captains Pattinson and Munday, was responsible for the destruction of L.62 over the Heligoland minefields. All this activity took place in the face of strong German opposition, mainly from seaplanes under the command of the German Naval ‘ace’, Christiensen, and many combats took place, culminating in a pitched battle on 4 June, 1918. On that day, Capt. Robert Leckie led a force of four F.2As and a single H.12 on an offensive patrol towards the Haaks Light Vessel, three hours flying time from Felixstowe. After two-and-a-half hours, one of the F.2As was forced down by a broken petrol feed pipe, and its pilot, Capt. R. F. L. Dickey, had no choice but to taxi to the Dutch coast. On the way, five German seaplanes made a half-hearted attack upon the crippled machine, losing one of their number to its gunners, the rest breaking off the action, hotly pursued by the H.12, while the three F.2As formed a protective circle over Dickey’s machine. Soon afterwards, a formation of ten more German seaplanes arrived and Leckie charged them head-on, losing his wireless aerial on the upper wing of the enemy leader and splitting up the formation. The battle which followed lasted forty minutes, during which time the flying-boats shot down two Germans and probably destroyed four more without loss to themselves, although one F.2A went down on the Zuider Zee with a broken petrol pipe during the action. This was repaired by the engineer, however, and the machine rejoined the others. On the way back to Great Yarmouth, Capt. J. Hodson’s aircraft had an engine failure, flight being maintained on half-power while repairs were effected. Two flying-boats had been lost, for the H.12 force-landed in Dutch waters also, and both crews were interned. In 1918 the range of the flying-boats was extended by the use of special lighters designed by Porte, the machines being floated on to the fighters and towed by destroyers to a launching point off the German coast, returning after reconnaissance flights to be towed home. This system had its limitations, but several successful operations were completed. Another method of extending range was the carriage of extra fuel in cans, and by this means flights of over nine hours’ duration were made, pilot fatigue being minimised by the fitting of dual control to the F.2A.
   Two illustrations are on record to prove the strength of the F.2A; in one, a machine was actually looped over Killingholme by an aggrieved American trainee, and in the other a single-engined approach aimed at Leeds Reservoir was misjudged and terminated in a ploughed field, the only damage incurred being strained bracing wires.


SPECIFICATION

   Power Plant:
   F.2 and H.12 - Two 250 h.p. Rolls-Royce Eagle I
   F.2A - Two 345 h.p. Rolls-Royce Eagle VIII
   Span: F.2, F.2A, and H.12 - 95 feet 7 1/2 inches
   Length:
   H.12 - 46 feet 6 inches
   F.2 and F.2A - 46 feet 3 inches
   Weight Loaded:
   H.12 - 10,650 pounds
   F.2 - 10,000 pounds
   F.2A - 10,978 pounds
   Total Area: F.2, F.2A, and H.12 -1,133 square feet
   Max. Speed:
   H.12 - 85 m.p.h.
   F.2 - 95 m.p.h.
   F.2A - 95-5 m.p.h.
   Endurance: F.2, F.2A, and H.12 - 6 hours (normal)
   Armament:
   H.12 - Up to four Lewis guns on flexible mountings in bow and pilot’s cockpit. Four 100-pound or two 230-pound bombs
   F.2 - Experimental gun installations for F.2A, max. bomb load of 460 pounds
   F.2A - Four to seven Lewis guns on flexible mountings, two 230-pound bombs

  

Porte/Felixstowe F.2C (1917)

   An experimental version of the F.2A, the F.2C did not pass beyond the prototype stage. It was fitted with a modified hull of lighter construction, having alterations to the front gun position, an open cockpit for the pilots, and no hull side hatches. The F.2C power units were initially 275 h.p. Rolls-Royce Eagle Ils, later replaced by the 322 h.p. Eagle VI. Official trials took place on 23 June, 1917, the machine showing a slightly better performance than the F.2A, but the margin was too small to justify interference with the F.2A production programme. However, the F.2C, serialled N65, saw active service with the R.N.A.S. at Felixstowe and on 24 July, 1917, flown by Wg. Cmdr. Porte, released two of the five 230-pound bombs which sank submarine UC-1. Some time later the machine was fitted with experimental pneumatic bomb-release gear which chose to be temperamental at the worst possible moment resulting in a surfaced U-boat escaping unscathed.


SPECIFICATION

   Power Plant: Two 275 h.p. Rolls-Royce Eagle II or 322 h.p. Eagle VI
   Span: 95 feet
   Length: 46 feet
   Weight Loaded: 10,240 pounds
   Total Area: 1,136 square feet
   Max. Speed: 98-5 m.p.h.
   Endurance: 6-5 hours
   Armament: Two Lewis guns, two 230-pound bombs


Porte/Felixstowe F.5 (1918)

   Intended as an improvement upon the F.3, the F.5 appeared in early 1918. Externally similar to its predecessors, and employing the standard Porte hull construction, it embodied a number of refinements developed as a result of experience with the previous designs. The top decking of the hull was deeper than before, and the pilots were seated in an open cockpit, while the gun positions were of the same arrangement as the F.3. Four 230-pound bombs could be carried in the standard underwing racks. The wing structure was entirely new, with a span greater than the F.3 and a modified section, also constant-chord ailerons. A broad-chord tailplane projected ahead of the fin leading edge, the rudder, and the ailerons, being horn-balanced. Serialled N90, the prototype was powered by two 350 h.p. Rolls-Royce Eagle VIIIs driving four-bladed tractor propellers, and on its official trials it displayed a much better performance than the F.3, even under conditions of overload. Unfortunately, the prototype F.5 fell foul of economics, for the large F.3 construction programme did not readily permit the introduction of a new type. A compromise was reached with the extensive modification of the F.5 to incorporate as many F.3 components as possible, resulting in a machine not wholly satisfactory, but nevertheless put into production. The hull of the modified machine was similar to that of N90, but its overall covering of plywood, with only the top decking of fabric, added considerably to the weight, which, in the completed aircraft, exceeded that of N90 by more than 1,000 pounds. The wing structure was that of the F.3, modified to take constant-chord ailerons, and the tail unit was identical to that of the prototype, although later F.5s had horn-balanced elevators. The slightly greater wing span of the F.5 as compared to the F.3 was accounted for by the ailerons, which extended beyond the wing-tips. Official test figures show that the performance of the production F.5 was inferior to that of the F.3, and in some instances this was further impaired by the fitting of lower powered engines, the 325 h.p. Rolls-Royce Eagle VII.
   Too late for operational service, the type was adopted as the R.A.F.’s standard post-war flying-boat and remained in service until replacement by Southamptons in 1925. In the summer of 1919, an early production F.5, N4044, toured Scandinavia to demonstrate the capabilities of flying-boats, covering 2,450 miles in 27 days and returning to Felixstowe fully serviceable. Another equally successful tour took place in 1923, when two F.5s commanded by Air Commodore Bigsworth completed a cruise to Gibraltar, Malta, Bizerta, and Oran without mishap.
   Before the Armistice, F.5 production had started in Canada at the factory of Canadian Aeroplanes Ltd to the order of the United States Air Board. These machines were fitted with the Liberty 12 engine of 400 h.p. and equipped the U.S. Naval Air Service in 1918. A series of structurally modified F.5s was also built by the U.S. Naval Aircraft Factory at Philadelphia; these too had the Liberty engine and were designated F.5L. The F.5L could carry 1,000 pounds of bombs and up to eleven machine-guns, and some mounted a Davis quick-firing gun in the bows. These machines gave years of service to the U.S. Navy,both in the Atlantic and the Pacific Fleets, later versions having a greatly enlarged fin and a horn-balanced rudder. Also in America, two converted F.5Ls formed the equipment of one of the first airlines to operate flying-boats, Aeromarine West Indies Airways, Inc., in 1920. In 1921, the Japanese company, Aichi of Nagoya, obtained a licence to build F.5s and produced fifteen machines which served with the Imperial Japanese Naval Air Service and made several notable long-distance flights, recording durations of over nine hours in some cases. In this country, the F.5 was used for a number of experiments, among which were the trial of auxiliary aerofoil aileron balances on N4838, and the fitting of a special hollow-bottom Saunders hull to N178. In 1924, Short Brothers produced an F.5, N177, with an all-metal hull, the first military flying-boat in the world to be so fitted. The F.5 formed the equipment of eight R.A.F. squadrons, a ninth, No. 230, being renumbered No. 480 Flight at the end of 1922 and forming the training establishment for flying-boats at Calshot.

SPECIFICATION

   Power Plant:
   Prototype - Two 350 h.p. Rolls-Royce Eagle VIII
   Production - Two 350 h.p. Rolls-Royce Eagle VIII or two 325 h.p. Rolls-Royce Eagle VII
   Canadian F.5s and American F.5Ls - Two 400 h.p. Liberty 12
   Span: 103 feet 8 inches
   F.5L-103 feet 9 inches
   Length : 49 feet 3 inches
   Prototype - 49 feet 6 inches
   Weight Loaded: 12,682 pounds
   Prototype - 12,268 pounds
   F.5L - 13,000 pounds
   Total Area: 1,409 square feet
   F.5L - 1,397 square feet
   Max. Speed:
   Prototype - 102 m.p.h.
   Production - 88 m.p.h.
   F.5L - 87 m.p.h.
   Endurance: 7 hours (normal)
   F.5L - 7-9 hours
   Armament:
   Four Lewis guns, four 230-pound bombs
   Canadian machines could have up to eight Lewis guns
   F.5L - maximum armament of one Davis gun, eleven Lewis guns. Normal armament was one Davis gun, four Lewis guns, and four 230-pound bombs or two 500-pound bombs

Porte/Felixstowe Fury (1918)

   John Porte’s last Felixstowe production was a huge triplane flying-boat, the largest British machine of its day, powered by no fewer than five 334 h.p. Rolls-Royce Eagle VII engines. The Fury was probably inspired by a large Curtiss triplane flying-boat which had been assembled and flown at Felixstowe in 1916, the Curtiss-Wanamaker, serialled No. 3073. This machine was the first delivered of an order for twenty, but even with its original four 250 h.p. Curtiss engines replaced by Rolls-Royce power units, official tests showed that the performance did not measure up to requirements and the order was cancelled. At the time, Porte had little opportunity and insufficient resources to deal with the redesign of the Curtiss-Wanamaker, but it is certain that as an advocate of the large flying-boat he did not forget it, and when the Fury appeared in 1918 several features of the Curtiss machine were embodied. Known to all at Felixstowe as the Porte Super Baby, the Fury was planned for an engine installation of three of the new 600 h.p. Rolls-Royce Condors but was completed before the Condor became available, so the engine mountings were modified to take five Rolls-Royce Eagles arranged as a central pusher flanked by two outboard pairs of pusher and tractor. The hull, basically employing a similar construction and profile to the other Felixstowe boats and 60 feet in length, was regarded as the best of all the Porte hulls. The top and central mainplanes were of equal span, the latter carrying the engines, while the lower mainplane was one bay shorter. The tail unit resembled that of the Curtiss-Wanamaker, with a biplane tailplane fitted with twin rudders mounted upon a central fin. The Fury design incorporated power-operated controls, using servo-motors, and it was almost certainly the first aircraft in the world to fly with these in operation although actually the Fury proved to be remarkably light on all controls and so the weighty servos were dispensed with. The machine’s designed loaded weight was 24,000 pounds, this being gradually increased during testing without adverse effect upon take-off or seaworthiness until it reached the figure of 33,000 pounds, at which enormous weight Porte himself coaxed the great machine into the air from Harwich Harbour. On another occasion, Major T. D. Hallam, d.s.C., flew the Fury with 24 passengers, fuel for seven hours, and 5,000 pounds of ballast. The tail unit was later modified to a more conventional assembly of biplane layout with triple rudders between the tailplanes, and the hull tested in model form in the Froude Tank at the National Physical Laboratory, some of the recommended modifications resulting from this testing being applied to the full-sized aircraft. Never used operationally, the Fury continued experimental flying after the Armistice, powered in its final form by five Rolls-Royce Eagle VIII engines of 365 h.p. each. A few months after Porte and Rennie were demobilised, the Fury stalled and crashed on take-off, possibly due to incorrect loading, the pilot and two crew members losing their lives.
   In August 1919, Porte joined the Gosport Aviation Co. Ltd., as chief designer, to work with an old friend, Herman Volk, who had become manager of the company. A number of designs was produced but none was built due to the post-war slump in orders. In October 1919 John Porte died at Brighton. He was thirty-five years old.


SPECIFICATION

   Power Plant: Five 334 h.p. Rolls-Royce Eagle VII, or five 365 h.p. Rolls- Royce Eagle VIII
   Span: 123 feet
   Length: 63 feet 2 inches
   Weight Loaded: 25,253 pounds (medium), 33,000 pounds (max. test)
   Total Area: 3,108 square feet
   Max. Speed: 97 m.p.h. at 2,000 feet
   Endurance: 7 hours (medium). In excess of 12 hours with max. fuel load
   Armament: Four Lewis guns and heavy bomb load

Wyvenhoe Flier (1909)

   Historically important as the first serious attempt to produce a flying-boat in Britain, work commenced upon the Wyvenhoe Flier in October 1908, supervised by its designer, Mr J. E. Humphreys, construction being carried out in a small hangar between Forrestt’s boatyard at Wyvenhoe and the river bank opposite Rowhedge, in Essex. Humphreys, a dental surgeon, was by no means an amateur regarding aerodynamics, having experimented with bird flight and structure since 1902, and had actually flown two of his own gliders from the cliffs at Fowey, Cornwall.
   The Flier was built by local skilled marine craftsmen, with the co-operation of Mr (later Sir James) Bird, managing director of Forrestts.
   In many ways advanced for its time, the machine was a biplane, with the wings mounted above the hull and the engine and propellers in mid-gap, thus anticipating a design layout for flying-boats that endured for a quarter of a century. For the first time in aviation history, extensive metal skinning was employed, both mainplanes being covered with light-gauge aluminium sheet. The coracle-type hull had a double skin of thin cedar planking, with varnished silk interposed, with a small scuttle in the bows serving as protection for the pilot. No water rudder was fitted. The lower wing was secured to the hull gunwales, its multiple spars as extensions of the hull ribs and curved downwards to the tips, which formed full-chord ‘air boxes’ for lateral stability on the water. A wheeled undercarriage consisting of two pairs of cycle-type wheels mounted in tandem on bamboo poles, and arranged to make use of the natural spring thereof, was designed to fit up under the lower wing, but was never used in practice. The upper wing, supported upon tubular steel interplane struts and wire braced, had large drooping tip extensions of triangular shape built up of long narrow sections covered with strips of rubber-impregnated cotton silk. These extensions were similar in function and appearance to the wing-tip feathers of a bird. Strut-mounted on the lower wing trailing edge was a bird-like tailplane/rudder, universally jointed, and of the same ‘feather’ construction as the wing tips. The control surfaces were completed by a triangular elevator, carried forward of the hull and wing structure on outriggers. Elevator and tailplane were both operated by a single control.
   A 35 h.p. J.A.P. Vee-eight air-cooled engine was transversely mounted on steel tubular bearers in mid-gap behind the pilot, driving two 8-foot diameter metal pusher propellers through shafts, bevel gears, and centrifugal clutches. The propeller blades were curved rearwards towards the tips, with the idea of concentrating the slipstream into a ‘jet wake‘ to assist thrust.
   The first launching was made on 3 April, 1909, in rather marginal conditions of wind and tide. Inevitably, a gust canted the machine, and it sank. Humphreys, aboard at the time, extricated himself from the numerous bracing wires with some difficulty. The Flier was salvaged at midnight, and returned to its shed. Repairs having been completed, the second launching took place on 15 April. Again bad fortune attended, for one of the propeller drive gears sheared. At a third launching on the 18th, everything appeared to be in order, and the machine was towed down river by steam tug to a point between the Alresford and Fingringhoe Banks, cast off, and the engine started. It was immediately apparent that the wing-tip air boxes created impossible water drag, and that with the engine stopped, directional control was nil. The machine was towed back for alterations to be made, these consisting of canoeshaped wing-tip floats with controllable water rudders at the stern.
   In the evening of 14 May, 1909, the Flier was towed to the swing bridge at Alresford Creek, and started up. This time, directional control proved excellent, the Flier skimming the water beautifully at a speed of 10 to 12 knots, but resisting all Humphreys’ efforts to ‘unstick’.
   Financial considerations precluded further development, and the Flier was abandoned. Its engine finally did take to the air, being sold to Mr E. T. Willows, who used it to power his little dirigible airship on her memorable flight from Cardiff to London.


SPECIFICATION

   Power Plant: One 35 h.p. J.A.P. Vee-eight air-cooled engine, with Bosch magneto
   Span:
   Main metal-clad wing section - 21 feet
   Wing-tip extensions - 10 feet 6 inches each
   O.A. Span - 42 feet
   Length, O.A.: 26 feet (Hull - 17 feet)
   Height: 12 feet
   Weight Loaded: 1,750 pounds
   Total Area: 1,100 square feet

Norman Thompson N.T.4 and N.T.4A (1915)

   On 4 October, 1915, the White and Thompson Company changed its name to the Norman Thompson Flight Company, Ltd, with F. P. H. Beadle as chief designer. The first machine to appear under the new name was the N.T.4. A development of the twin-engined Round Britain Race entrant of 1914, the N.T.4 was ordered for R.N.A.S. use, becoming known as the ‘America’ flying-boat, and later, with the introduction of the Curtiss H.12, as the ‘Small America’ although there was little resemblance between the Norman Thompson and Curtiss machines. It should be noted that at this time there was a confusing tendency to class all flying-boats as ‘Americas’, regardless of type or manufacture.
   A biplane, with twin 150 h.p. Hispano-Suiza pusher engines driving two- bladed propellers, the N.T.4 had two side-by-side seats in an enclosed cabin. The hulls were made by S. E. Saunders at Cowes. The first production machine of a batch of six, No. 8338, was experimentally fitted with a two-pounder Davis gun mounted horizontally above the cabin roof. This gun was subsequently removed, not having been used operationally. Commencing with the second production batch, the N.T.4s had modified cabin windows to give better vision, and were fitted with 200 h.p. Hispano-Suiza engines. With these modifications the machines were designated N.T.4A, the first one, No. 9061, being stationed at Calshot. A total of over fifty machines of both versions served with the R.N.A.S. at seven coastal stations, where they were employed for patrols, and later for training duties.


SPECIFICATION

   Power Plant:
   N.T.4 - Two 150 h.p. Hispano-Suiza engines
   N.T.4A - Two 200 h.p. Hispano-Suiza engines
   Span: 78 feet 7 inches
   Length: 41 feet 6 inches
   Loaded: N.T.4A-6,469 pounds
   Total Area: 936 square feet
   Max. Speed: N.T.4A-95 m.p.h.
   Endurance: 4 hours
   Armament: Light bombs, .303-inch Lewis gun in cabin roof


Norman Thompson N.2C (1918)

   The Norman Thompson N.2C was a 1918 development of the N.T.4A. The wings and tail unit were standard N.T.4A components, but unlike the previous boat-built hulls characteristic of this company, the N.2C had a hull built on the Porte principle. Norman Thompson had been contractors for F.2A hulls since the spring of 1917, and so were familiar with the Porte-type construction. The power units were two pusher Sunbeam Arab engines of 200 h.p. each, driving four-bladed propellers. Construction of two prototypes commenced in January 1918. These were officially serialled N82 and N83, but the machines, designed for patrol work and equipped with Lewis guns, bombs, and wireless, arrived too late for production or service, being scrapped due to post-war economy upon the take-over by Handley Page, Ltd.


SPECIFICATION
   Power Plant: Two 200 h.p. Sunbeam Arab
   Span: 78 feet 7 inches
   Length: Not available
   Weight Loaded: 6,700 pounds
   Total Area: 936 square feet
   Armament: One or two Lewis guns, light bombs

Norman Thompson N.T.2B (1916)

   A development of the White and Thompson No. 3 Boat of 1914, the N.T.2B was powered initially by the 160 h.p. Beardmore pusher engine. The crew of two were enclosed in a cabin fitted with side-by-side seating and dual control, and in common with other machines produced by this company, the after part of the hull was extremely narrow with a long dorsal tail fin, while the wing-tip floats were attached directly to the undersurface of the lower wing. Accepted by the Admiralty, the N.T.2B was ordered into production, some of the first batch of fifty machines being fitted with the 150 h.p. Hispano- Suiza engine, examples of this being N2555 and N2561. The machine proved to be a great success, and the production requirements soon outstripped the capability of the Norman Thompson works alone, so construction contracts were opened with S. E. Saunders at Cowes, and with Supermarine at Woolston, Southampton. Late in 1917, it was decided to fit the 200 h.p. Sunbeam Arab engine, which, owing to its greater torque, had to be mounted slightly starboard of centre. An example of the Arab-powered N.T.2B was machine N2294. This engine, however, fell short of requirements, and the ultimate production version was fitted with the 200 h.p. Hispano-Suiza, the torque problem in this case being dealt with by slewing the engine mounting. The first 200 h.p. machine was N2569.
   Altogether, more than one hundred and fifty machines were built, remaining the standard training type for flying-boat pilots until the Armistice, supplemented by smaller numbers of other machines. They served with the R.N.A.S. at Calshot, Lee-on-Solent, and Felixstowe.
   No further development took place, owing to the fact that Norman Thompson was absorbed by Handley Page, Ltd. The latter company sent two machines to Peru in 1919, for air transport work. These were N2284 and N2293. One N.T.2B was on the civilian register as G-EAQO.


SPECIFICATION

   Power Plant:
   Prototype/early production - 160 h.p. Beardmore
   Some early production - 150 h.p. Hispano-Suiza
   Trial installation, 1917 - 200 h.p. Sunbeam Arab
   Late production - 200 h.p. Hispano-Suiza
   Span: 48 feet 4 3/4 inches
   Length: 27 feet 4 1/2 inches
   Weight Loaded: Sunbeam Arab - 3,169 pounds
   Total Area: 453 square feet
   Max. Speed: Sunbeam Arab - 85 m.p.h.
   Endurance: Not available
   Armament: Nil

Pemberton-Billing Flying-boats (1913/1914)

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   Undeterred by failure, Pemberton-Billing’s reference to his marine aircraft as ‘not aeroplanes which float, but boats which fly’ was borne out by his next flying-boat project, the P.B.7, of 1914. In this design, the forward part of the hull consisted of a cabin cruiser motor boat, powered by a 225 h.p. Sunbeam engine, while the after part, including wings, propellers, and tail unit, was detachable. In the assembled state, extended drive linkage connected the Sunbeam to the twin pusher propellers. The P.B.7 layout was intended to eliminate the problem of docking a large flying-boat by loading the motor boat at a pier, then connecting up with the flight structure at a convenient offshore mooring. In emergency, the flight structure could be jettisoned on the water, leaving the seaworthy motor boat to proceed alone and unhindered. A batch of P.B.7s were on order for the German Navy, and at the outbreak of war several motor boats of this type were complete and ready to have the flight structure fitted. Work on them was stopped and the design adapted into the S.S.1 military flying-boat.
   The S.S.1 project consisted of a scaled-down version of the P.B.7, equipped with folding wings. Intended for launching from a surfaced submarine, the machine would jettison its flight structure after action, returning to base as a fast motor launch. In the event, it was not built, partly because Pemberton-Billing had joined the R.N.A.S. and was planning the anti-Zeppelin raid on Friedrichshaven, and partly because the company now had priority wartime contracts to fulfil. Eventually the company was transferred to the capable hands of Hubert Scott-Paine, retaining the original description of its marine aircraft, ‘Supermarines’, as the company name.

SPECIFICATION

P.B.7
   Power Plant: One 225 h.p. Sunbeam
   Span: 57 feet 6 inches
   Length: 34 feet
   Weight Loaded: 3,950 pounds
   Total Area: 558 square feet
   Max. Speed: 70 m.p.h. (estimated)

Perry-Beadle Flying-boat (1913)

   In an attempt to emulate the success of the Sopwith Bat Boat, the Perry-Beadle machine was built by F. P. Hyde Beadle and Copland Perry at their Twickenham works in late 1913, with the hull sub-contracted to Saunders of Cowes.
   Generally of conventional layout, the machine had an unusual power arrangement which followed a design theory of the time that future flyingboats would have engines and crew accommodated within the hull. A 60 h.p. E.N.V. eight-cylinder Vee-type engine was totally enclosed in the bows, with tube-shrouded chain transmission to twin tractor propellers carried on mid-span interplane struts. Hull decking over the engine was removable for maintenance. The hull itself was beautifully streamlined to a fish-like profile, the monocoque rear section with integral fin and tailplane merging into a deep forward section which embodied the planing bottom and a perpendicular bow. A single step was formed by the junction of the rear monocoque and forward sections. The entire hull and tail surfaces were covered by Saunders ‘Consuta’ copper-sewn plywood. The upper wing was of normal wooden construction, equipped with ailerons and fabric covered. The lower wing was covered with ‘Consuta’ and of unusual airfoil section, in that the point of maximum camber lay at fifty per cent of the 4-foot chord. No wing-tip floats were fitted, reliance for lateral water stability being placed upon the watertight wing itself. Control surfaces were operated by external wires from the wheeled control column, and from rudder pedals.
   The Perry-Beadle was exhibited at the 1914 Aero Show at Olympia, but then the outbreak of war intervened, and flight trials could not be arranged until 1915. At this time, an association known as the Lakes Flying Company was operating with marine aircraft on Lake Windermere, an ideal locale with calm water and few wartime restrictions. The machine was transported there in July 1915, and after assembly, flotation tests were made. The results were not promising, for the machine lay so low in the water that the lower wing trailing edge and rudder base were submerged. This fact, combined with the fish-like hull, quickly earned it the local sobriquet of‘Jonah’s Whale’. Flight trials were attempted by Mr Stanley Adams of the Lakes Company, but he failed to get the machine off the water, due to the high drag set up by the immersed lower wing. The Perry-Beadle remained at Windermere, and, after removal of the engine, was finally broken up.


SPECIFICATION

   Power Plant: One 60 h.p. E.N.V. Vee-eight engine
   Span: 35 feet
   Length: 26 feet
   Height: 9 feet
   Weight Loaded: 1,600 pounds
   Total Area: 290 square feet

Phoenix P.5 Cork (1918)

   In 1917, while recognising the proven efficiency of the Porte-designed flyingboats, the Admiralty decided to evaluate fully the Linton Hope monocoque hull by using it in the design of a new flying-boat of similar size/weight ratio to the Felixstowe boats. This type of hull had not been extensively used, because it required skilled labour, and was therefore unsuited to mass-production, but its success with the 1917 A.D. Boat helped to convince the Air Department that it was capable of further development. Specification N.3B was drawn up for the new machine, authorisation being granted for the construction of two prototypes. The hulls were built by May, Harden and May, of Southampton Water, and the contract for the flight structure and final assembly given to the Phoenix Dynamo Manufacturing Co. Ltd, of Bradford. The two hulls were not identical; one had a true planing bottom extending to the rear step, while the other was of similar profile to the Supermarine Baby and Blackburn N.1B, with the main planing bottom terminating amidships at the main step, and a small auxiliary external step fitted towards the stern. The hulls were completed and sent to Bradford in April 1918, where, for some reason of policy, only the one with the full planing bottom was utilised. This hull had a bow gunner’s cockpit, two separate cockpits for the pilots, and just forward of the rear spar was a hatch for the flight engineer. There was a waist gunner’s hatch on either side of the hull aft of the lower wing trailing edge. The first machine, N86, assembled at the Brough seaplane base, was complete on 7 August, 1918. The power units were two 352 h.p. Rolls-Royce Eagle VIIIs, driving four-bladed tractor propellers. After satisfactory maker’s trials, N86 reached the Isle of Grain for official trials on 24 August. There, some trouble was experienced with the wing fabric, for a new type of varnish used was a failure and the fabric became dangerously soggy. The second prototype was now under construction, with its wings treated with normal dope, so these wings were sent to be fitted to N86, the originals being returned to Bradford for re-covering. Experience with N86 indicated that the wings were set too low, consequently the second aircraft, N87, was modified to have the lower wing centre section carried above the hull on a shallow faired pylon. N87’s hull was similar to that of its predecessor but the rear step was further aft. Other differences were a larger rudder, and two ‘dustbin’ gunner’s cockpits built into the upper wing trailing edges, outboard of the centre section. The original wings of N86 were fitted, but the use of an incorrect type of dope again caused delay, and N87 did not reach Brough until March 1919.
   After the Armistice, the large numbers of Felixstowe boats available precluded any possibility of the Cork attaining full production status, but the two existing machines remained in use for several years, proving beyond doubt the durability of the Linton Hope hull. N87 was eventually fitted with two 450 h.p. Napier Lion engines, with a revised system of struts supporting the engine bearers, and N86 acquired the larger rudder, being also equipped for night flying, although there is no record of this being practised.


SPECIFICATION

   Power Plant:
   Two 352 h.p. Rolls-Royce Eagle VIII
   N87 - later, two 450 h.p. Napier Lion
   Span: 85 feet 6 inches
   Length: 49 feet 2 inches
   Weight Loaded: (Normal) 11,600 pounds (N86)
   Total Area: 1,273 square feet
   Max. Speed: (Normal load) 106 m.p.h. (N86)
   Armament:
   N86 - five Lewis guns, and maximum bomb load of two 520-pound bombs
   N87 - bomb load as N86, with seven Lewis guns

Porte/Felixstowe Baby (1916)

   During the H.4 hull experiments, work had commenced on the construction of a very large three-engined flying-boat designed by Porte, now in command of the Felixstowe air station. This machine’s official designation was submerged by Naval humour, and ‘Baby’ it remained. The prototype, No. 9800, had a boat-built hull, plywood covered with a single step. Equipped with an enclosed cabin, the hull measured 56 feet 10 inches from bow to stern, having a maximum beam over the side fins of no less than 14 feet. The power units were three 250 h.p. Rolls-Royce engines, the prototype of the later Eagle, and were disposed as a centrally mounted pusher and two outboard tractors. After initial tests the bows were lengthened by 3 feet to improve seaworthiness, but the machine proved rather slow and underpowered. Twenty Babies were ordered, at least ten being completed by May, Harden and May, of Southampton Water. Some of these machines had a 260 h.p. Green engine as the central unit, and all had modified outboard engine mountings consisting of single interplane struts, which replaced the original diamond-shaped arrangement. Performance was later improved by fitting more powerful Rolls-Royce engines, including the Eagle VIII of 360 h.p., but the design of the Baby did not lend itself to the installation of effective armament, the structure providing a multitude of ‘blind spots’. No. 9800 was experimentally fitted with a large-calibre Davis gun in the bows,'but this was not used operationally. Some machines had a Scarff ring-mounted Lewis gun in the bow cockpit, but the majority were armed with Lewis guns fired through windows and ports from within the hull.
   The Porte Baby flying-boats were flown on oversea patrols from Felixstowe and Killingholme, taking part in the efficient ‘Spider Web’ patrol centred on the North Hinder Light Vessel. It was here, on 1 October, 1917, that the Baby captained by Flight Commander N. Sholto Douglas fought a gallant but unequal action with three German aircraft, during which two of the flyingboat’s engines were hit and stopped, forcing it to alight on the sea where a further attack caused more damage and wounded one of the crew. Undaunted, the others effected temporary repairs to the machine, and after taxying for nine long hours made landfall on the Suffolk coast, from where the Baby was towed back to Felixstowe. As a re