P.Bowers Curtiss Aircraft 1907-1947 (Putnam)
H-12 (Model 6A) - The H-12 of late 1916 was a considerably enlarged version of earlier H-boats and was powered initially with two 160 hp Curtiss V-X-X engines. Eighty-four went to the RNAS, which named them Large Americas. Again, Britain was dissatisfied with the underpowered Curtiss engines and substituted 275 hp Rolls-Royce Eagle I engines in their H-12s, later replaced by 375 hp Eagle VIIIs.
With US participation in the war becoming imminent, funds for the expansion of Naval aviation became available and the Navy was at last able to buy twin-engined flying-boats. The first of twenly H-12s was delivered in March 1917. Engines were the 200 hp Curtiss V-2-3, later replaced with Liberties.
US Navy serial numbers: A152, A765/783
H-12A (Model 6B) - Original H-12s re-engined in Britain with 275 hp Rolls-Royce Eagle I engines and later Curtiss versions altered at the factory for engines to be installed in the United Kingdom. For the H-12A model at least, some hulls were built by the Niagara Motor Boat Company of Tonawanda, NY.
RNAS serial numbers: 8650/8699 (50), N1160/l179 cancelled (20), N1510/1519 (10).
Patrol-bomber flying-boat. Four crew.
Two 275 hp Rolls-Royce Eagle I.
Span 92 ft 8 1/2 in (28,25 m); length 46 ft 6 in (14,17 m); height 16 ft 6 in (5,02 m); wing area 1,216 sq ft (112,96 sq m).
Empty weight 7,293 lb (3,308 kg); gross weight 10,650 lb (4.830,75 kg).
Maximum speed 85 mph (136,79 km/h) at 2,000 ft (610 m); climb to 2,000 ft (610 m) 3,3 min, to 10,000 ft (3,048 m) 29,8 min; service ceiling 10,800 ft (3,292 m); endurance 6 hr at cruising speed.
Armament-four flexible .303-in Lewis machine-guns, four 100 lb (45 kg) or two 230 lb (104 kg) bombs.
H-12B (Model 6D) - Believed to be H-12s and H-12As re-engined with 375 hp Rolls-Royce Eagle VIIIs.
RNAS serial numbers: 4330/4353 (24).
H-12L - The US Navy followed the British lead in refilling its H-12s with more powerful engines. When the 360 hp low-compression Liberty became available late in 1917, the H-12s on hand were fitted with these new V-12 engines and were redesignated H-12L. The last H-12Ls were withdrawn from squadron service in July 1920.
H-16 (Model 6C) - The H-16 was the final model in the Curtiss H-boat line and was built in greater quantities than any or the other twin-engined Curtiss flying-boals.
It was a logical development of the H-12 and was originally intended to use the 200 hp Curtiss V-X-X engine. However, the Liberty became available before the first H-16 was completed so all 124 H-16 deliveries to the US Navy were made with the 360 hp low-compression Liberty. These were replaced by 400 hp Liberty 12As in postwar years. The sixty British versions were shipped without engines and were fitted with 345 hp Rolls-Royce Eagles on arrival in the United Kingdom.
In addition to 184 built by Curtiss, 150 H-16s were built at the Naval Aircraft Factory in Philadelphia. Originally, the Navy-built models were to be identified as Navy Model C, but all were operated as H-16s. The first Curtiss-built H-16 was launched on 22 June, 1918, while the first Navy-built model had come out of the factory on 27 March. H-16s were shipped overseas to US bases in Britain in 1918; H-16s remained in postwar service with the F-5Ls until May 1930. Prices for Navy-built H-16s ranged from $55,547 less engines for the first example down to $21,680 apiece for the last thirty.
Because of their great similarity, identification problems between the H-16 and the F-5L were inevitable. The distinctive features of the H-16 were originally the unbalanced ailerons with significant sweep back toward the tips as on the America and H-12, and the enclosed pilots' cockpit. The rudder was unbalanced, but could not be distinguished from early F-5L outlines because the balance area of the F-5L rudder was below the horizontal tail at that time. In postwar years, some H-16s were fitted with F-5L ailerons, had the pilots' enclosure removed, and were given added balanced area to the top or the rudder, further complicating the identity problem.
US Navy serial numbers: (Curtiss) A784/799 (16), A818/867 (50), A1030/1048 (19), A4039/4078 (40). (NAF) A1049/1098 (50), A3459/3558 (100).
RAF serial numbers: N4890/4949 (60) (4950/4999 cancelled).
H-16-1 - One H-16 had its engines turned around and was completed as a pusher. No advantage accrued; the adaptation proved to be excessively tail-heavy.
H-16-2 - A second pusher H-16 (A839) was produced by Curtiss with more consideration for the change of balance. Wings of slightly increased span were swept back 5 1/2 degrees. Straight-chord ailerons used with F-5L-type horn balance brought the revised span to 109 ft 7 in (33,27 m). The increased wing area required additional rudder area in the form of two auxiliary rudders mounted on the tailplane.
Patrol-bomber flying-boat. Four crew.
Two 400 hp Liberly 12A.
Span 95 ft 0 3/4 in (28,97 m); length 46 ft 1 1/2 in (14,05 m); height 17 ft 8t in (5,4 m); wing area 1.164 sq ft (108,13 sq m).
Empty weight 7,400 lb (3.356,58 kg); gross weight 10,900 lb (4.944,15 kg).
Maximum speed 95 mph (152,88 km/h); climb 4,700 ft (1,432 m) in 10 min; service ceiling 9,950 ft (3.03) m): range 378 miles (608 km).
Armament 5-6 flexible 0.30-in Lewis machine-guns, four 230 lb (104 kg) bombs.
G.Swanborough, P.Bowers United States Navy Aircraft Since 1911 (Putnam)
Curtiss H-12, H-16
In 1914 Curtiss developed a then giant flying-boat to the special order of Mr Rodman Wanamaker, who planned to use it for a transatlantic flight. The outbreak of war cancelled these plans and the aeroplane, which had been named America, was sold to the Royal Naval Air Service. Under the factory designation Model H, sister ships with improved 150 hp engines were also sent to England, where as a class they were called Americas.
The original America was a daring design concept at the time, and left a permanent mark on subsequent large flying-boat development. Its effects could be seen on biplane designs that remained in production right up to World War II. The America, fitted with two 90hp Curtiss OX engines, did not have the power to carry enough fuel for the trip, so a third engine was mounted above the wing. Earlier, flotation difficulties had been encountered when power was applied to the engines for take-off; because of their high location, they exerted a considerable downward push on the nose that tended to drive it under water. This was corrected by adding more flotation volume to the nose in the form of auxiliary structures called sponsons that were built on to the lower portion of the hull from the bow to the step. This was to remain a feature of many flying-boats built into the 1930s.
In 1916 the Navy ordered an improved version of the America under the designation H-12. This featured the laminated wood veneer hull of the prototype, longer wings, and 200 hp Curtiss V-X-X engines. Equivalent models sold to Britain were called Large Americas. The initial Navy order was followed by another for 19 production versions. In 1918 some of these were converted to H-12L by the installation of the new Liberty engine.
A further improved model was introduced early in 1917 as the H-16, still powered with the 200 hp V-X-X. Many were sold to Britain in knockdown condition, still as Large Americas. They were then assembled and test flown in England, fitted with British engines. Commander Porte of the Royal Navy, who had assisted in the design of the original America, developed an improved hull design for the H-16, and the British versions were built at RNAS Felixstowe as F.2, F.3 and F.5.
By the time the US Navy became interested in production of the H-16, the Liberty engine was in the offing and was specified for the Navy's H-16s. However, in spite of the engine change there was no need to designate the production version as H-16L because there were no Curtiss-powered Navy models to require distinction. Because of the commitment of most of its production facilities to other war-time models, Curtiss could not meet the Navy's demand for H-16s, so the Navy undertook H-16 manufacture on its own at the Naval Aircraft Factory. This version was originally designated Navy Model C, as the third design built by Navy shops. This was the first aeroplane built by the new Naval Aircraft Factory, and the first example was completed on March 27, 1918. The original Curtiss designation was finally used.
In continuing attempts to improve the design, Curtiss built one H-16 with the engines turned around to drive pusher propellers. Because the engines had to be moved aft to get the propellers behind the wing, it became necessary to sweep the wings back slightly to relocate the centre of lift to match the new centre of gravity position. The Navy built 150 H-16s, and Curtiss built 124 for the Navy, some of which remained in service until 1928.
TECHNICAL DATA (H-16)
Manufacturer: Curtiss Aeroplane and Motor Co, Inc, Garden City, LI and Buffalo, NY; and Naval Aircraft Factory, Philadelphia, Pennsylvania.
Type: Patrol/bomber flying-boat.
Accommodation: Crew of four.
Power plant: Two 400 hp Liberty 12s.
Dimensions: Span, 95 ft 0 3/4 in; length, 46 ft 1 1/2 in; height, 17 ft 8 5/8 in; wing area, 1,164 sq ft.
Weights: Empty, 7,400 lb; gross, 10,900 lb.
Performance: Max speed, 95 mph at sea level; initial climb, 10 min to 4,700 ft, service ceiling, 9,950 ft; range, 378 st miles.
Armament: Five-six flexible 0.30-in Lewis machine guns. Four 230 lb bombs.
H-12: A152; A765-A783.
H-16 (Curtiss): A784-A799; A818-A867; A1030-A1048; M039-M078.
H-16 (NAF): A1049-A1098; A3459-A3558.
O.Thetford British Naval Aircraft since 1912 (Putnam)
Curtiss H.12 Large America
The H.12, known as the Large America, was by far the most famous of the series of Curtiss flying-boats used by the RNAS. It was developed from the H.4 Small America and was both larger and more powerful. Despite a distinguished operational record, related in detail in C F Snowden-Gamble's classic The Story of a North Sea Air Station, the H.12 was handicapped by weakness of the hull planing bottom which made take-off hazardous in all but the calmest of seas.
The original power plant of two 160 hp Curtiss engines proved inadequate and was superseded by two Rolls-Royce engines. A total of 71 H.12s reached the RNAS, the first batch being Nos.8650 to 8699 and the second N4330 to 4350. Great Yarmouth air station made its first H.12 patrol with No.8660 on 1 May 1917 and Felixstowe air station with No.8661 on 13 April 1917, initiating the famous 'Spider-web' patrols.
In both its roles, as an anti-submarine reconnaissance aircraft and as an anti-Zeppelin fighter, the H.12 enjoyed outstanding success. The first of these was on 14 May 1917, when No.8666 from Great Yarmouth, flown by F/Lt Galpin, shot down the airship L22 about 18 miles NNW of Texel Island. This was the first Zeppelin claimed by a flying-boat. The second Zeppelin to be shot down by an H.12 was L43, which fell to Felixstowe's No.8677, flown by F/Sub-Lt Hobbs, on 14 June 1917.
Against U-boats the first success went to F/Sub-Lts Morrish and Boswell, who attacked UC-36 on 20 May 1917, and the second to H.12s 8662 and 8676, UB-20 on 29 July 1917. Another victory was scored on 22 September 1917, when NO.8695 was instrumental in sinking UB-32. Another submarine, the UC-6, was claimed by F/Sub-Lts Hobbs and Dickey on 28 September 1917.
Some of the H.12s were modified later in their careers, and were almost indistinguishable from the F.2A. These H.12s were styled 'Converted Large Americas'. On 31 October 1918, when there were 18 H.12 boats still in service, six were of the converted type.
'War Flight' of RNAS. Felixstowe and 'Boat Flight' of RNAS. Great Yarmouth (later No.228 Squadron. RAF). Also at RNAS. Killingholme and with NO.234 Squadron (Tresco) and No.240 Squadron (Calshot).
TECHNICAL DATA (CURTISS H.12)
Description: Anti-submarine and anti-Zeppelin patrol flying-boat with crew of four. Wooden structure with wood and fabric covering.
Manufacturers: Curtiss Aeroplanes and Motor Corporation, Buffalo. Hammondsport, NY.
Power Plant: Originally two 275 hp Rolls-Royce Eagle I. Later two 345 hp Eagle VII or 375 hp Eagle VIII.
Dimensions: Span, 92 ft 8 1/2 in. Length, 46 ft 6 in. Height, 16 ft 6 in. Wing area, 1,216 sq ft.
Weights: Empty, 7,293 lb. Loaded, 10,650 lb.
Performance: Maximum speed, 85 mph at 2,000 ft. Climb, 3.3 min to 2,000 ft; 29.8 min to 10,000 ft. Endurance, 6 hr. Service ceiling, 10,800 ft.
Armament: Up to four Lewis guns on flexible mountings and four 100 lb or two 230 lb bombs below the wings.
Curtiss H.16 Large America
The H.16 was an improved and enlarged version of the more famous H.12 and was delivered to Britain in 1918. It represented a notable advance on the H.12, in that it incorporated the stronger and more seaworthy Porte-type hull, thus bringing the American boats into line with their British counterparts, the Felixstowe series, whose design they had originally helped to inspire. The wheel had turned full circle.
The initial Admiralty contract for H.16 flying-boats covered 15 aircraft, N4060 to 4074, fitted with twin 250 hp Rolls-Royce Eagle engines. This was followed by an additional contract for 110 aircraft, N4890 to 4999, but the end of the war saw the last 50 cancelled. The second batch of H.16s mounted twin 375 hp Rolls-Royce Eagle engines.
H.16 Large Americas rivalled the Felixstowe boats in performance, but they figured less in records of the period and no particularly outstanding operations are associated with the type. On 31 October 1918 there were some 69 on charge with the RAF, but 39 of these were in store or with contractors. At about the same time another 50 or so H.16s were operated round British shores by the US Navy. The US Navy versions had twin 330 hp Liberty engines and were based at Killingholme. It is alleged that one of the American H.16s at Killingholme was actually looped by an over-exuberant pilot!
H.16s served with No.228 Squadron at Great Yarmouth and Killingholme, No.230 Squadron (Felixstowe). No.238 Squadron (Cattewater) and No.257 Squadron (Dundee).
TECHNICAL DATA (CURTISS H.16)
Description: Anti-submarine patrol flying-boat with a crew of four. Wooden structure with wood and fabric covering.
Manufacturers: Curtiss Aeroplanes and Motors Corporation, Buffalo, Hammondsport, NY.
Power Plant: Two 375 hp Rolls-Royce Eagle VIII.
Dimensions: Span. 95 ft. Length. 46 ft 1 1/2 in. Height, 17 ft 8 in. Wing area, 1,000 sq ft.
Weights: Empty, 7,363 lb. Loaded. 10.670 lb.
Pelformance: Maximum speed. 98 mph at 2,000 ft; 95 mph at 6,500 ft; 92 mph at 10,000 ft. Climb, 512 ft/min; 3.7 min to 2,000 ft; 14.6 min to 6,500 ft; 28 min to 10,000 ft. Endurance, 6 hr. Service ceiling, 12,500 ft.
Armament: Twin Lewis machine-guns on ring mounting in bows and amidships. Provision for two further Lewis guns to fire through the side of the hull and for bombs mounted on racks beneath the wings.
Jane's All The World Aircraft 1919
CURTISS MODEL H.16A. FLYING BOAT.
Wing span. upper plane 96 ft. 6 5/8 in.
Wing span, lower plane 68 ft. 11 3/8 in.
Depth of wing chord 84 19/64 in.
Gap between wings 96 9/16 in.
Length of machine overall 40 ft. 1 15/32 in.
Height of machine overall 17 ft 8 5/8 in.
Angle of incidence 4 degrees.
Dihedral angle 1 degree.
Wing curve R.A.F. No. 6.
angle of incidence 2 degrees pos.
Wings, upper (without ailerons) 616.2 sq. ft.
Wings, lower 443.1 sq. ft.
Ailerons 131 sq.ft.
Horizontal-stabilizer 108 sq. ft.
Vertical stabilizer 31.1 sq. ft.
Elevators 58.4 sq. ft.
Rudder 27.9 sq. ft.
Non-skids 24 sq. ft.
Total supporting surface 119.3 sq. ft
Loading (weight carried per sq. ft.
of supporting surface) 8.54 lbs.
Loading (per r.h.p.) 15.42 lbs.
Net weight, machine empty 6,956 lbs.
Gross weight, machine and load 10,172 lbs.
Useful load 3,216 lbs.
Fuel and oil 1,527 lbs.
Crew 660 lbs.
Useful load 1,029 lbs.
Total 3,216 lbs.
Speed, max. (horizontal flight) 95 m.p.h.
Speed, min. (horizontal flight) 55 m.p.h.
Climbing speed 4,000 ft. in 10 mins.
Two Liberty 12-cylinder, Vee, four-stroke cycle. Water cooled.
Horse power (each motor 330) 660
Weight per rated h.p. 2.55
Bore and stroke 5 in. x 7 in.
Fuel consumption (both motors) 62.8 galls, per hour.
Fuel tank capacity 300 galls.
Oil capacity provided 10 galls.
Fuel consumption per b.h.p. 0.57 lbs. per hour.
Oil consumption per b.h.p. 0.03 lbs. per hour.
Material - Wood.
Diameter. - According to requirements of performance.
Pitch. - According to requirements of performance.
At economic speed, about 675 miles.
Hull Box. - Dimensions: 44 ft. 9 in. x 11 ft. x 9 ft. 4 in. ; gross weight, 1,300 lbs.
Panel Box. - Dimensions: 30 ft. 4 in. x 7 ft. 7 in. x 6 ft. 6 in.; gross weight, 4,850 lbs.
Panel Box. - Dimensions: 21 ft. 2 in. x 7 ft. 5 in. X 3 ft. 6 in.; gross weight, 2,170 lbs.
Engine Box.- Dimensions: 6 ft. 2 in. x 4 ft. 4 in. x 2 ft. 9 in.: gross weight, 1,645 lbs.
Flight, May 10, 1917.
THE "TOTALLY ENCLOSED" AEROPLANE.
Since the war the Curtiss firm have built a great number of large flying boats, following more or less along the lines of the "America," from which some have, however, differed very considerably as regards size. A case in point is the flying boat known as the type H-12, which was illustrated in our issue of April 26th, 1917. In general arrangement this machine differs comparatively little from the "America," and it has not, therefore, been included in our descriptions of "totally enclosed" aeroplanes to which category it naturally belongs.