| Model H family | |
|---|---|
 Curtiss H-12Large America in RNAS service. | |
| General information | |
| Type | Experimental flying boat |
| Manufacturer | Curtiss Aeroplane and Motor Company |
| Primary users | United States Navy |
| Number built | 478 |
| History | |
| First flight | 23 June1914 (America) |
| Developed from | Curtiss Model F[1] |
| Variants | Felixstowe F.1 Felixstowe F.2 |
TheCurtiss Model H was a family of classes of early long-rangeflying boats, the first two of which were developed directly on commission in theUnited States in response to the£10,000 prize challenge issued in 1913 by the London newspaper, theDaily Mail, for the first non-stop aerial crossing of the Atlantic. As the first aircraft having transatlantic range and cargo-carrying capacity, it became the grandfather development leading to early international commercial air travel, and by extension, to the modern world of commercial aviation. The last widely produced class, the Model H-12, was retrospectively designatedModel 6 by Curtiss' company in the 1930s, and various classes have variants with suffixed letters indicating differences.
Having transatlantic range and cargo carrying capacity by design, the first H-2 class (soon dubbed"The Americans" by theRoyal Navy) was quickly drafted into wartime use as a patrol and rescue aircraft by the RNAS, the air arm of the British Royal Navy. The original two "contest" aircraft were in fact temporarily seized by the Royal Navy, which later paid for them and placed an initial follow-on order for an additional 12 – all 14 of which were militarized (e.g. by adding gun mounts) and designated the "H-4" (the two originals were thereafter the "H-2" Models to air historians). These changes were produced under contract from Curtiss' factory in the last order of 50 "H-4s", giving a class total of 64, before the evolution of a succession of larger, more adaptable, and more robust H-class models. This article covers the whole line of nearly 500 Curtiss Model Hseaplaneflying boat aircraft known to have been produced, since successive models – by whatever sub-model designation – were physically similar, handled similarly, essentially just being increased in size and fitted with larger and improved engines – the advances ininternal combustion engine technology in the 1910s being as rapid and explosive as any technological advance has ever been.
When London'sDaily Mail newspaper put up a£10,000 prize for thefirst non-stop aerial crossing of the Atlantic in 1913, American businessmanRodman Wanamaker became determined that the prize should go to an American aircraft and commissioned theCurtiss Aeroplane and Motor Company to design and build an aircraft capable of making the flight. TheMail's offer of a large monetary prize for "an aircraft with transoceanic range" (in an era with virtually no airports) galvanized air enthusiasts worldwide, and in America, prompted a collaboration between the American and British air pioneers:Glenn Curtiss andJohn Cyril Porte, spurred financially by the nationalistically motivated financing of air enthusiastRodman Wanamaker. The class, while commissioned by Wanamaker, was designed under Porte's supervision following his study and rearrangement of the flight plan and built in the Curtiss workshops.[2] The outcome was a scaled-up version of Curtiss' work for the United States Navy and hisCurtiss Model F.[1] With Porte also asChief Test Pilot, development and testing of two prototypes proceeded rapidly, despite the inevitable surprises and teething troubles inherent in new engines, hull and fuselage.
TheWanamaker Flier was a conventionalbiplane design with two-bay, unstaggered wings of unequal span with two tractorengines mounted side by side above thefuselage in the interplane gap. Wingtip pontoons were attached directly below the lower wings near their tips. The aircraft resembled Curtiss' earlier flying boat designs, but was considerably larger in order to carry enough fuel to cover 1,100 mi (1,770 km). The three crew members were accommodated in a fully enclosed cabin.
NamedAmerica[2] and launched 22 June 1914, trials began the following day and soon revealed a serious shortcoming in the design: the tendency for the nose of the aircraft to try to submerge as engine power increased whiletaxiing on water. This phenomenon had not been encountered before, since Curtiss' earlier designs had not used such powerful engines. In order to counteract this effect, Curtiss fittedfins to the sides of the bow to add hydrodynamic lift, but soon replaced these withsponsons to add more buoyancy. Both prototypes, once fitted with sponsons, were then calledModel H-2s incrementally updated alternating in succession. These sponsons would remain a prominent feature of flying boat hull design in the decades to follow. With the problem resolved, preparations for the transatlantic crossing resumed, and 5 August 1914 was selected to take advantage of thefull moon.
These plans were interrupted by the outbreak of theFirst World War, which also saw Porte, who was to pilot theAmerica withGeorge Hallett, recalled to service with the BritishRoyal Navy. Impressed by the capabilities he had witnessed, Porte urged theAdmiralty to commandeer (and later, purchase) theAmerica and her sister aircraft from Curtiss. By the late summer of 1914 they were both successfully fully tested and shipped to England 30 September, aboardRMSMauretania.[3] This was followed by a decision to order a further 12 similar aircraft, one Model H-2 and the remaining asModel H-4s, four examples of the latter actually being assembled in the UK bySaunders. All of these were essentially identical to the design of theAmerica, and indeed, were all referred to as "Americas" in Royal Navy service. This initial batch was followed by an order for another 50.
These aircraft were soon of great interest to theBritish Admiralty as anti-submarine patrol craft and for air-sea rescue roles. The initial Royal Navy purchase of just two aircraft eventually spawned a fleet of aircraft which saw extensive military service during World War I in these roles, being extensively developed in the process (together with many spinoff or offspring variants) under the compressed research and development cycles available in wartime. Consequently, as the war progressed, the Model H was developed into progressively larger variants, and it served as the basis for parallel developments in theUnited Kingdom underJohn Cyril Porte which led to the "Felixstowe" series of flying boats with their better hydrodynamic hull forms, beginning with theFelixstowe F.1 — a hull form which thereafter became the standard in seaplanes of all kinds, just as sponsons did for flying boats.
Curtiss next developed an enlarged version of the same design, designated theModel H-8, with accommodation for four crew members. Aprototype was constructed and offered to theUnited States Navy, but was ultimately also purchased by the British Admiralty. This aircraft would serve as the pattern for theModel H-12, used extensively by both the Royal Navy and the United States Navy. Upon their adoption into service by the RNAS, they became known asLarge Americas, with the H-4s receiving theretronymSmall America.
As built, the Model H-12s had 160 hp (118 kW)Curtiss V-X-X engines, but these engines were under powered and deemed unsatisfactory by the British so inRoyal Naval Air Service (RNAS) service the H-12 was re-engined with the 275 hp (205 kW)Rolls-Royce Eagle I[4] and then the 375 hp (280 kW) Eagle VIII.[5] Porte redesigned the H-12 with an improved hull; this design, theFelixstowe F.2, was produced and entered service. Some of the H-12s were later rebuilt with a hull similar to the F.2, these rebuilds being known as theConverted Large America. Later aircraft for the U.S. Navy received theLiberty engine (designatedCurtiss H-12L).[6]
Curiously, the Curtiss company designationModel H-14 was applied to a completely unrelated design (seeCurtiss HS), but theModel H-16, introduced in 1917, represented the final step in the evolution of the Model H design.[7] With longer-span wings, and a reinforced hull similar to the Felixstowe flying boats, the H-16s were powered by Liberty engines in U.S. Navy service and by Eagle IVs for the Royal Navy. These aircraft remained in service through the end of World War I. Some were offered for sale as surplus military equipment at $11,053 apiece (one third of the original purchase price.)[8] Others remained in U.S. Navy service for some years after the war, most receiving engine upgrades to more powerful Liberty variants.
With the RNAS, H-12s and H-16s operated from flying boat stations on the coast in long-range anti-submarine and anti-Zeppelin patrols over theNorth Sea. A total of 71 H-12s and 75 H-16s were received by the RNAS, commencing patrols in April 1917, with 18 H-12s and 30 H-16s remaining in service in October 1918.[5][9]
U.S. Navy H-12s were kept at home and did not see foreign service, but ran anti-submarine patrols from their own naval stations. Twenty aircraft were delivered to the U.S. Navy.[6] Some of the H-16s, however, arrived at bases in the UK in time to see limited service just before the cessation of hostilities. Navy pilots disliked H-16 because, in the event of a crash landing, the large engines above and behind the cockpit were likely to break loose and continue forward striking the pilot.[10]
Data from Curtiss Aircraft 1907–1947,[14] British naval aircraft since 1912[15]
General characteristics
Performance
Armament
Related development
Aircraft of comparable role, configuration, and era
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