A.Jackson British Civil Aircraft since 1919 vol.3 (Putnam)

Supermarine Sea Lion I

   Single seat, wooden racing flying-boat, powered by one 450 h.p. Napier Lion driving a pusher airscrew, built at Woolston for the 1919 Schneider Trophy Race. One aircraft only: G-EALP, no c/n. piloted in the race, which was declared void through fog, 10.9.19 by Cdr. B. D. Hobbs. Struck flotsam and holed the hull when taking off from Swanage Bay after a precautionary landing and sank on alighting off Bournemouth Pier. Hull loaned to the Science Museum, South Kensington, 1921.
   Span, 35 ft. 0 in. Length, 24 ft. 0 in. A.U.W., 2,900 lb. Max. speed, 147 m.p.h.


Supermarine Sea Lion II

   Originally the single seat Sea King II amphibian scout powered by one 300 h.p. Hispano-Suiza, built at Woolston 1921. One aircraft only: G-EBAH, c/n 1154, registered to the manufacturers 16.12.21, first flown by H. C. Biard 3.22. Rebuilt as flying-boat with 450 h.p. Napier Lion, wings of reduced area and renamed Sea Lion II. Winner of the Schneider Trophy contest at Naples 10-12.8.22 piloted by H. C. Biard, who averaged 145-7 m.p.h. over the course of 200-2 nautical miles.
   Span, 32 ft. 0 in. Length, 24 ft. 9 in. Tare wt., 2,115 1b. A.U.W., 2,850 lb.


Supermarine Sea Lion III

   The Sea Lion II G-EBAH, rebuilt with two bay wings and increased rudder area for the 1923 Schneider Trophy Race at Cowes. Piloted by H. C. Biard, it averaged 151-16 m.p.h. to come third. Transferred to the R.A.F. 4.12.23 as N170.
   Span, 32 ft. 0 in. Length, 27 ft. 6 in. Tare wt., 2,400 lb. A.U.W., 3,275 lb. Max. speed, 155 m.p.h. Cruise, 125 m.p.h.

D.James Schneider Trophy Aircraft 1913-1931 (Putnam)

Supermarine Sea Lion I

   The old Pemberton Billing Co. and its Supermarine Works at Woolston, near Southampton, were bought by Hubert Scott-Paine in 1916 when Noel Pemberton Billing became a Member of Parliament. It was renamed Supermarine Aviation Works and in 1918 designed and built the Baby, to Air Board specification N.1B, which was one of the very few single-seat fighter flying-boats to be produced during the First World War. The Baby was a biplane with a wing span of 30ft 6 in (9-29 m) and, powered by a 200 hp Hispano-Suiza engine, had a maximum speed of 116 mph (186-6 km/h). Two prototypes, N59-60, were built and flown, but the Baby did not go into quantity production because military requirements changed.
   When the Schneider Trophy contests were re-established in 1919 and the first postwar venue was to be Bournemouth, Scott-Paine decided that because of its proximity to the Supermarine factory his company would enter the lists. Since time was short, he obtained one of the Babies, whose forward hull had been modified to reduce spray while on the water as part of a programme to produce a civil Baby to be known as the Sea King. The Hispano-Suiza engine was replaced by a 450 hp Napier Lion twelve-cylinder broad-arrow engine driving a two-blade wooden pusher propeller. Although the redesign of this aircraft was to produce a purely racing machine, it was fully equipped with a bilge pump, sea anchor and mooring equipment. The hull, of Linton Hope design, was of similar construction to that used in the Blackburn Pellet. The single-bay mainplanes and centre section were built up around two spruce spars and wooden ribs which were fabric covered. The four mainplanes were built separately and were rigged without stagger but with dihedral from the flat centre section. Large balanced ailerons were carried on all four mainplanes. The interplane struts were sloped out toward the tops to support the longer-span upper mainplane. Deep, narrow, stabilizing floats were carried beneath the lower mainplanes. The tailplane was mounted on top of the fin and was braced on each side by a pair of steel-tube struts to the hull. A horn-balanced rudder, extended downward to act as a water rudder, was carried on the fin which was covered with wood sheeting. The remainder of the tail unit was of wood and fabric construction. The engine was mounted on four steel-tube struts carrying two ash engine-bearers and supported the upper centre section on four more struts. An oval-shaped radiator was mounted in front of the engine and was enclosed in an aluminium nacelle. The redesign work was entrusted to the young Reginald J. Mitchell, who in later years was to become renowned as the designer of a series of Supermarine racing floatplanes for the Schneider contests and of the Spitfire.
   The use of the Lion engine prompted the name Sea Lion for this little racer which received the civil registration G-EALP. The eliminating trials to select the British team were scheduled for 3 September, and while the Sopwith, Fairey, and Avro companies had flown their aircraft by the day before the trial, the Sea Lion’s first flight was delayed by the non-delivery of the propeller - due to a strike at the manufacturers. However, it arrived in time for engine running to begin at 8 p.m. in the evening before the trials; but torrential rain prevented these taking place. On 5 September Sqn Ldr Basil Hobbs, the Supermarine pilot, made the initial flight. Flight trials continued with all four British aircraft, the final decision to include the Sea Lion in place of the Avro entrant being delayed until 9 September when a new propeller gave the Sea Lion an additional five or six miles per hour.
   The events of the contest day are recorded elsewhere in this book, but afterwards the Sea Lion was dismantled and its hull was loaned to the Science Museum in London for an exhibition in 1921. Sadly it was broken up some years later when the Museum no longer required it.


   Single-seat racing biplane flying-boat. Wood and metal construction. Pilot in open cockpit.
   One 450 hp Napier Lion IA twelve-cylinder water-cooled normally-aspirated geared broad-arrow engine driving a 7 ft 10 in (2-38 m) diameter two-blade fixed-pitch wooden propeller.
   Span 35 ft (10-66 m); length 26 ft 4 in (8 02 m); height 11 ft 8 in (3-55 m); wing area 380 sq ft (35-3 sq m).
   Empty weight 2,000lb (907kg); loaded weight 2,900lb (1,315kg); wing loading 7-63 Ib/sq ft (37-22 kg/sq m).
   Maximum speed 147 mph (236-57 km/h).
   Production - one Sea Lion I built by conversion of Baby by Supermarine Aviation Works, Woolston, Southampton, in 1919.
   Colour - believed to have been dark blue hull and tailplane support struts, with remainder pale blue, grey or silver; engine nacelle natural aluminium; Supermarine in large white capital letters on hull sides forward of mainplanes with small Sea Lion above, white civil registration letters G-EALP on hull sides aft of mainplanes; white contest number 5 on fin.


Supermarine Sea Lion II

   Expedience and economy were ever the watchwords of British aircraft manufacturers in the years between the wars and, clearly, were observed by Hubert Scott-Paine at Supermarine when producing aeroplanes for the Schneider contests. Following the use of the N.1B Baby hull in the Sea Lion I, when the decision was made to build an entrant for the 1922 contest the company used an existing airframe on which to base it. During 1919 two civil sporting amphibian versions of the Baby, named Sea King I, had been built but neither had been sold. One of these became the Sea Lion I; in 1921 the second was developed as the Sea King II, an amphibian fighting scout with a single .303-in Lewis machine-gun and provision for light bombs, but when it, too, failed to win orders it was modified to become the Sea Lion II G-EBAH.
   The Sea King hull, constructed of circular-section wooden frames with wood skinning, was retained. The bow was modified, which shortened the Sea King hull to 24 ft 9 in (7-54 m) in its Sea Lion II form. A built-on wooden planing bottom and steps, which were divided into watertight compartments, were added. The upper surface was single-skin planking and the whole structure was covered with fabric and doped. The manually-operated wheeled undercarriage and all military equipment and fittings were removed. The Sea King’s mainplanes structure was retained, with four vertical interplane struts replacing the splayed-out struts of the Sea Lion I. The Sea King’s wing area was reduced by introducing a narrower chord in the mainplanes, and their span is believed to have been increased by 1ft 6in (45cm) to reach 32ft (9-75m). The mainplanes, built as four separate sections, were attached to the upper and lower centre sections. They were built up around two spruce spars with wooden ribs, all wire braced and fabric covered. In place of the earlier 300 hp Hispano-Suiza engine, a 450 hp Lion II, loaned by Napier, was installed, which drove a four-blade wooden pusher propeller of about 8 ft 6 in (2-59 m) diameter. To offset the increased torque and maintain stability, the fin area above the tailplane was enlarged by forward curvature of the leading edge. Because the engine was mounted high between the wings and produced a high thrust-line resulting in a pitching moment, the tailplane had a reverse camber to counteract this. Fuel was supplied to the engine by a high-pressure air system with all fuel lines being kept short and run as clear of the hull as possible.
   The earlier Sea King II had not only proved itself capable of aerobatics - Henri Biard, Supermarine’s test pilot had rolled and spun the aircraft - but it had also been very stable at all speeds. These characteristics were inherited by the Sea Lion II which was a very tractable aeroplane.
   The 1922 Schneider contest was scheduled to take place in Naples during the latter part of August, but the Italians decided to advance the date by some ten days. Unfortunately, the Sea Lion II was still incomplete when news of the change was received by the Royal Aero Club, and so the work was pressed ahead with all speed. When the day came for preliminary engine running the Lion started almost immediately and it was decided to make a preliminary test flight. With Biard aboard, the Sea Lion II got airborne very easily after a short take-off run - but suddenly, when it was some 200 ft over rows of luffing cranes and the masts of ships in Southampton Docks, the Lion engine stopped. Biard managed to pick out a stretch of clear water and glided down to alight safely. The Sea Lion was towed back to Woolston where a fault in the fuel system was diagnosed and corrected. But a precious day was used up.
   The following evening Biard again flew the Sea Lion and, finding all was going well, opened the throttle wide to achieve a speed in excess of 150mph, faster than any British flying-boat had then flown. There followed several days while final modifications were made to the airframe and flying time was built up, then the Sea Lion was dismantled and crated for its journey by sea to Naples.
   With the Sea Lion re-assembled, Biard and the Supermarine team launched a cloak-and-dagger operation, first to find out the strength of the French and Italian opposition, and then to conceal from their prying eyes and stop watches the capabilities of the British flying-boat. Accordingly, Biard confined his full-throttle runs to an area well clear of Naples Bay, and made sure that his practice circuits always included some cautious turns around the pylons. This plan worked so well that the Italians publicly proclaimed the inferiority of the Sea Lion when compared with the Macchi M.17 and Savoia S.51. But there was almost disaster, when he flew too close to Vesuvius in an attempt to look down into its crater, and a strong thermal suddenly lifted the Sea Lion some 2,000ft above its original flight path.
   In the contest Biard’s tactical flying, plus the Sea Lion’s speed, brought the Trophy to Britain; additionally they established world closed-circuit speed, duration and distance records, the first to be recognized for seaplanes.
   Soon after its return to the Supermarine factory, the Sea Lion II G-EBAH was bought by the Air Ministry for development flying work, but it has not been established whether it was moved to Felixstowe; it was not, however, removed from the Civil Aircraft Register.
   There was also a plan to fly G-EBAH in the 1922 King’s Cup air race. That a flying-boat should take part in a race flown entirely over land was a tribute to the reliability of the Lion engine. A report in Flight of 7 September records that 'at the moment of going to press we learn this machine will not start'. There were no other references to the Sea Lion in reports of the race.


   Single-seat racing biplane flying-boat. Wood and metal construction. Pilot in open cockpit.
   One 450 hp Napier Lion II twelve-cylinder water-cooled normally-aspirated geared broad-arrow engine driving an 8 ft 6 in (2-59 m) diameter four-blade fixed-pitch wooden pusher propeller. Fuel: 55 gal (250 litres).
   Span 32 ft (9-75m); length 24ft 9in (7-54m); height 12ft (3-65m) approx; wing area 384 sq ft (35 -67 sq m).
   Empty weight 2,115lb (959kg); loaded weight 2.850lb (1,292kg); wing loading 7-42 Ib/sqft (36-22 kg/sq m).
   Maximum speed 160mph (257-49 km/h).
   Production - one Sea Lion II (G-EBAH) converted from Sea King II by Supermarine Aviation Works, Southampton, in 1922.
   Colour - believed to have been overall blue hull, interplane and tailplane support struts; cream or white mainplanes and tailplane; white registration G-EBAH on rear hull sides and national letter G on rudder, black contest number 14 on white panel on hull sides aft of cockpit


Supermarine Sea Lion III

   For the 1923 Schneider contest the Air Ministry decided that the old Sea Lion II G-EBAH should participate again. Reginald Mitchell at Supermarine rapidly produced drawings to initiate a general modification programme aimed at cleaning up the hull and increasing its fineness ratio. As a result the hull length was increased by 2 ft 9 in (83 cm). A new planing bottom was attached to the hull and the bow section refined; in addition the wing span was reduced by 4 ft (1-21 m), and the area of the fin and rudder was increased by making them taller.
   During the flight-test programme the shoe-shaped floats were removed and oval-section stabilizing floats, with pairs of small hydrovanes at their forward end, were mounted on short struts and wire braced to the underside of the lower mainplanes near the tips. For the first time on a Sea Lion, a small glass windscreen was mounted in front of the open cockpit.
   Power for the Sea Lion III came from a 525 hp Napier Lion III which drove a four-blade wooden pusher propeller. The engine, in its aluminium nacelle with a circular-section radiator housed in a long-chord tubular cowling, was supported on a pair of N-struts; the fuel lines were carried up inside a streamlined radiator support strut from the hull fuel tank to the engine.
   A strange feature of this cleaning-up process was that the engine starting handle was permanently fixed to the power unit and protruded from the port side of the nacelle; moreover, the tailplane had no less than eight wire-braced support struts, and the original combined water-rudder/tailskid was retained.
   In the contest, although Biard and the Sea Lion III returned a speed some 12 mph faster than that at which they had won the previous year’s event, they were outclassed by the Curtiss CR-3s and could only take third place.
   During the first few weeks following the contest, Biard flew the Sea Lion III on some further flight trials; then during the first week of December it was taken on RAF charge, serialled N170 and moved to Felixstowe.


   Single-seat racing biplane flying-boat. Wood and metal construction. Pilot in open cockpit.
   One 525 hp Napier Lion III twelve-cylinder water-cooled normally-aspirated geared broad-arrow engine driving an 8 ft 8 in (2-64 m) diameter four-blade fixed-pitch wooden pusher propeller. Fuel: 60 gal (272 litres).
   Span 28ft (8-53m); length 28ft (8-53m); wing area 360sq ft (33-44sq m).
   Empty weight 2,400 lb (1,088 kg); loaded weight 3,275 lb (1,485 kg); wing loading 9-09 lb/ sq ft (44-4 kg/sq m).
   Maximum speed 175 mph (281-61 km/h); alighting speed 55 mph (88-51 km/h).
   Production - one Sea Lion III (G-EBAH) converted from Sea Lion II by Supermarine Aviation Works, Woolston, Southampton, in 1923.
   Colour - believed overall blue hull, silver mainplanes and tail unit, natural aluminium engine nacelle. Black registration letters G-EBAH on white panel on hull sides, and contest number 7 on white panel on nose aft of cockpit and on rudder. A sealion’s ‘face’ was painted in white on the noses of the hull and the two stabilizing floats as was the name Sea Lion III on the hull sides beneath the cockpit.

G.Duval British Flying-Boats and Amphibians 1909-1952 (Putnam)

Supermarine Sea King I and II (1919)

   When the First World War ended, the Supermarine Company survived the resultant financial slump due to brilliant leadership and sound business sense, and in the five years following the Armistice produced seven flying-boats and flying-boat amphibians, some of which were conversions of military machines and some new designs. Most of them proved successful, and the few that failed to secure orders initially were soon improved and modified until they, too, proved a financial asset to the Company. The two Sea Kings belonged to the latter category.
   The Sea King I was a development of the Supermarine Baby, now rendered obsolete by Government policy, and was aimed at the civil market which showed increasing interest in amphibian machines. This first Sea King had the same wing span as the Baby, but the power unit was a pusher 160 h.p. Beardmore, and a fin and rudder of large area was fitted, with a combined water rudder/tail-skid at the rear end of the hull. The manually-operated undercarriage was arranged to swing upwards and outwards from the hull to its retracted position for water operation. The hull itself was generally identical to that of the Baby, but the single cockpit was moved slightly aft on a raised turtle-decking, and a padded headrest faired into the decking top. Completed in 1919, the Sea King I had a maximum speed of 109 m.p.h. at an all-up weight of 2,250 pounds, being advertised as a single-seat sporting amphibian. No orders were received, and the machine was retained by the company as a flying test bed, in which capacity it carried out flying tests fitted with the 240 h.p. Siddeley Puma, the eventual power unit of the Supermarine Channel.
   The Sea King II was a development of the Mk. I, and also completed in 1919, powered by a 300 h.p. Hispano-Suiza engine. Built as an amphibian, this version had its wing span increased to 32 feet, retaining the Mk. I tail surfaces, and at an all-up weight of 2,850 pounds attained a speed of 125 m.p.h. Registered as G-EBAH, the Sea King II was fitted out as a military amphibian fighting scout. In 1921, when it was certain that no orders were forthcoming, the machine was rebuilt with wings of reduced chord, retaining the original span, and re-engined with a 450 h.p. Napier Lion engine, with the amphibian undercarriage removed. Thus modified, G-EBAH was renamed Sea Lion II, and subsequently won the 1922 Schneider Trophy Race.

SPECIFICATION

   Power Plant:
   Mk.I - One 160 h.p. Beardmore or one 240 h.p. Siddeley Puma
   Mk.II - One 300 h.p. Hispano-Suiza.
   Span:
   Mk.I - 30 feet 6 inches
   Mk.II - 32 feet
   Length:
   Mk.I - 26 feet 4 inches,
   Mk.II - 24 feet 9 inches
   Weight Loaded:
   Mk.I - 2,250 pounds
   Mk.II - 2,850 pounds
   Total Area:
   Mk.I - 309 square feet.
   Mk.II - 352 square feet
   Max. Speed:
   Mk.I - 109 m.p.h.
   Mk.II - 125 m.p.h.
   Endurance: Both Marks - 3 hours
   Armament: Mk. II - single .303-inch Lewis gun, provision for light bombs


Supermarine Sea Lion I (1919)

   After Great Britain’s victory in the 1914 Schneider Trophy race, the First World War intervened, and the contests were suspended until 1919 when the Royal Aero Club was charged with organising the contest on behalf of this country, as the Trophy holders. Bournemouth was chosen as the venue, with Cowes the headquarters for accommodation and servicing. Supermarine, in the advantageous position of having recent experience with small highspeed flying-boats and amphibians, and with the race virtually upon their doorstep, decided to enter a specially built racing flying-boat, and chose as the power unit the newly-developed Napier Lion engine of 450 h.p., hence the name - Sea Lion. Of slightly larger wing span than the Sea King and Baby, the Sea Lion was a mere 24 feet in length, the whole machine dominated by the large engine nacelle, strut-mounted high in the centre section, with the engine driving a four-bladed pusher propeller. The tailplane was mounted on the top of the single fin, and wing-tip floats attached directly to the undersurface of the short-span lower mainplane, which was carried over the hull top by short struts as in the Supermarine Baby. The designer was a brilliant young man named Reginald Joseph Mitchell, later designer of the immortal Spitfire. Registered G-EALP, the Sea Lion successfully passed its tests, and with Sqn. Ldr. Hobbs as pilot was prepared for the race. Unfortunately, the day chosen, 10 September, 1919, proved to be dull and misty, only four of the competitors attempting to complete the course. Hobbs was one of them, and had to alight in Swanage Bay to find his bearings, but without success, so he decided to return as best he could to Bournemouth. On taking off, he struck some object in the water, badly holing the Sea Lion’s hull. As a result, when an alighting was made between Christchurch and Boscombe, the machine began to sink. Both Hobbs and the Sea Lion were rescued, but the contest was abandoned. Following this, the Sea Lion was dismantled, its hull being loaned to the Science Museum for exhibition in 1921.


SPECIFICATION

   Power Plant: One 450 h.p. Napier Lion IA
   Span: 35 feet
   Length: 24 feet
   Weight Loaded: 2,900 pounds
   Total Area: Not known
   Max. Speed: 147 m.p.h.
   Endurance: 2-3 hours


Supermarine Sea Lion II (1922)

   The Schneider Trophy races of 1920 and 1921 were both won by Italy with no opposition, and a third win in the 1922 contest would have meant an outright victory and retention of the Trophy by that country. Fortunately for British prestige, Supermarine decided to enter one machine, the Sea Lion II, which, because of the non-appearance of the two French entries, became the sole challenger. The Sea Lion II was originally the single-seat Sea King II amphibian fighting scout of 1921, rebuilt as a flying-boat, with the 300 h.p. Hispano-Suiza engine replaced by a 450 h.p. Napier Lion. The Sea King mainplane structure was retained, the wing area being reduced by modification to a smaller chord, and to offset the greater torque the fin area above the tailplane was enlarged by a forward curvature. Apart from these modifications, the machine differed little from its original form, retaining the registration of G-EBAH. The actual contest, held at Naples on 10 and 12 August, 1922, was won by the Sea Lion, piloted by H. C. Biard, who employed airmanship and tactics of a high degree. During the preliminary trials, Biard had deliberately kept the Sea Lion throttled back, and banked somewhat clumsily on the turns, which lulled the three Italian competitors into a false sense of security. In the race itself, Biard was the first away, recording a first lap speed of over 150 m.p.h., and this was held for six laps. For the next few laps he nursed his engine, during which time the nearest Italian closed up to a mere 20 seconds behind. On the final lap, Biard gave the Sea Lion full throttle, crossing the finishing line one-and-a-half minutes ahead of his nearest rival, winning the Trophy for Great Britain at an average speed of 145-7 m.p.h. This victory was all the more noteworthy in that it was a private venture due to the individual enterprise of Mr Hubert Scott-Paine and Mr H. T. Vane of the Supermarine and Napier companies respectively. It also brought to public notice for the first time the name of R. J. Mitchell, by that time Supermarine’s chief engineer and designer and responsible for the Sea Lion.


SPECIFICATION

   Power Plant: One 450 h.p. Napier Lion II.
   Span: 32 feet
   Length: 24 feet 9 inches
   Weight Loaded: 2,850 pounds
   Total Area: Not available
   Max. Speed: Officially 125 m.p.h., but this was probably deliberately misleading for tactical reasons, as in the contest the machine attained a maximum speed of just under 160 m.p.h.
Endurance: 3 hours


Supermarine Sea Lion III (1923)

   After the 1922 success, the seventh Schneider Trophy contest was held at Cowes, Isle of Wight, on 27 and 28 September, 1923. For the first time a government-sponsored team of three aircraft, all Curtiss floatplanes, was entered by the United States Navy as the principal challengers to Great Britain, who entered a team of three aircraft from the manufacturers.
   The Italian teams and two of the British entries were victims of accidents and mechanical troubles, leaving just the Supermarine Sea Lion III to face the entire opposition, consisting of the Americans and a French machine.
   The Sea Lion III was the original Sea Lion II rebuilt with two-bay mainplanes, and having vertical tail surfaces of similar profile to the Sea King II but of slightly larger area. Hull modifications increased the overall length to 27 feet 6 inches, and the wing-tip floats were now mounted upon struts. The power unit was a Napier Lion III of 450 h.p., driving a four- bladed pusher propeller.
   The Sea Lion II registration, G-EBAH, was retained, and the racing number ‘7’ was allocated, the pilot being H. C. Biard. In the race, two of the Curtiss machines were the first to start, and their first lap speed indicated that unless mechanical trouble intervened the contest was a foregone conclusion. Outclassed, Biard and the Sea Lion nevertheless made a gallant effort, gaining third place at an average speed of 151-56 m.p.h. The Sea Lion III was transferred to the Royal Air Force on 4 December, 1923, receiving the serial N170.


SPECIFICATION

   Power Plant: One 450 h.p. Napier Lion III
   Span: 32 feet
   Length: 27 feet 6 inches
   Weight Loaded: 3,275 pounds
   Total Area: Not available
   Max. Speed: 165 m.p.h.
   Endurance: 3 hours

Журнал Flight

Flight, September 4, 1919.

THE JACQUES SCHNEIDER CUP RACE

The Machines

The Supermarine Flying-boat

   As it incorporates several new features, the flying-boat built by the Supermarine Aviation Co. is, up to the present, more or less of a "dark horse," and its makers do not wish any information published before the race. The machine is not, however, a freak built entirely for speed at any cost, and the makers are prepared to take it out in any sea that is likely to be encountered in that part of the world at this time of the year. It is a flying-boat more or less on the lines of previous Supermarine flying-boat scouts, and is fitted with a 450 h.p. Napier "Lion" engine. It is of interest to mention that this machine is capable of the evolutions of the small land scouts, such as looping, rolling, spinning, etc. It will be interesting to see how the seaworthy and necessarily heavier flying-boat will compare with the lighter-built float seaplanes.