A Transatlantic Flying Boat
World War I saw the debut of submarines and aircraft in modern warfare. Appropriately, Allied aircraft soon became hunters of U-boats. The first American-built aircraft produced specifically for that purpose were the Curtiss America-series flying boats.
A year before the war erupted in Europe, the London Daily Mail offered a L10,000 ($50,000) prize for the first flight between North America and Great Britain. In response, millionaire businessman Rodman Wanamaker commissioned Glenn L. Curtiss to build two aircraft capable of taking the prize. Only the year before, Curtiss had designed the world's first practical flying boat. A greatly enlarged version of that aircraft became the Model H, and Wanamaker named the first of these two flying boats the America.1
Curtiss went to work with gusto in his factory at Hammondsport, in the Finger Lakes region of upstate New York. The Curtiss design team reflected the international nature of the competition, with the wings designed by Britons B. Douglas Thomas and Lieutenant John C. Porte, a Royal Navy officer on leave. When test flights began in June 1914, they revealed that the America's bow tended to submerge when taxiing. The team designed projections—the first sponsons on a flying boat—to increase buoyancy of the forward fuselage. Sponsons became a standard feature in most of the world's larger flying boats over the next 30 years. (Curtiss had already designed the stepped hull, to enable seaplanes to overcome the suction of hydrostatic friction and break free of the surface for takeoffs.)
A unique control arrangement attached the ailerons to foot pedals, deflecting one or the other aileron downward to turn. Movement of the control stick operated the aircraft's elevators, and the control wheel turned the rudder. Twin pusher, 90-horsepower Curtiss OX engines were fitted between the wings. A third engine was briefly added to the America's upper wing to help generate the power needed for the transatlantic attempt. However, the fuel consumption of the third engine would probably have been counterproductive to a transatlantic crossing. The two pilots and a mechanic sat in an enclosed cockpit (although the later H variants and F-series designs had open cockpits).2
Aviation historians Gordon Swanborough and Peter M. Bowers wrote: "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."3
As preparations were made for the transatlantic flight—which would have several stops en route for refueling—it was decided that Porte would pilot the aircraft with Curtiss as copilot and George Hallett as mechanic. The America was christened at Hammondsport on 22 June 1914, and began taxi and flight trials.
The America's transatlantic flight, scheduled to begin on 5 August 1914, was cancelled because of the outbreak of war in Europe. Porte returned to Britain and persuaded the Admiralty to purchase the two Model H aircraft for long-range patrol duties, a remarkable concept at a time when most of the world's air forces were principally using small artillery spotters developed from prewar sport planes. Many reports have claimed that no U.S.-designed aircraft saw combat in World War I, but the "America boats"—as the type was dubbed—served with distinction in the war.
Curtiss produced 56 H-boats-called H.4 "Small Americas" in Britain-for the Royal Naval Air Service, armed with machine guns and bomb racks. These crossed the Atlantic aboard ship, leaving the Daily Mail's prize to be claimed by a British-built Vickers Vimy shortly after the war. Another eight were built in Britain.
The Small Americas' pioneering antisubmarine patrols made significant contributions to the British war effort. Several H.4s were assigned to Commander Porte at the naval air station at Felixstowe. Larger Curtiss-built aircraft based on the America design served the British and American navies as H-12s and H-16s (known in Britain as "Large Americas"). These heavy flying boats claimed four U-boats sunk and two Zeppelins destroyed in aerial combat.
Porte would also create a new hull fitted with the Curtiss-designed wings and tail assembly that became known as Felixstowe flying boats. Among these, the F.2A and F.3 saw extensive wartime use with British forces; the Porte-designed F.5, based in several respects on the America design, arrived too late for wartime service but was produced at British and American factories and served both nations' services into the mid-1920s. Coming full circle, Curtiss built many of the F-5Ls, and after the war some were converted for civilian transport—the original purpose for which the Model H was designed.
The U.S. Navy built 150 H-16s at the Naval Aircraft Factory in Philadelphia, while the Curtiss factory at Hammondsport produced another 124. These were the first aircraft produced at the Naval Aircraft Factory.5 The H-16s remained in U.S. Navy service for a decade, the last being retired in 1930.
The Curtiss Model H-16 was rated at a maximum speed of 95 miles per hour with a range of almost 400 miles. That aircraft, powered by two Liberty 400-horsepower engines, could lift a crew of four men. It was armed with five .30-caliber Lewis machine guns and could carry four 230-pound bombs. In his continuing efforts to improve performance while developing new designs, Curtiss built one H-16 with the engines turned around to drive pusher propellers. Because this meant moving the two engines farther aft to get the propellers behind the wing, it became necessary to sweep the wings back slightly to relocate the center of lift to correspond to the new center of gravity.
During the war Curtiss also developed the HS-series (H-Small) of single-engine flying boats, essentially a scaled-down version of his large H-series aircraft. The U.S. Navy ordered this aircraft into large-scale production as a coastal flying boat. Curtiss built 678 of these while the Naval Aircraft Factory and several other firms pushed the total production of HS-series aircraft to the then-phenomenal total of 1,095 aircraft-more than any previous U.S. naval aircraft.6 A further improved variant, the HS-3, had revised hull lines. Curtiss and the Navy built only seven of these as production halted at the end of the war.
While the Curtiss America was not the first aircraft to fly across the Atlantic, another Curtiss-designed flying boat was: The NC-4—commanded by Lieutenant Commander Albert C. Read. It did so in May 1919, two weeks before the Vimy's flight. The NC-4 did not win the Daily Mail's prize because its flight exceeded the prize's time requirement.
1. Curtiss designated his flying boats with letters in sequential order.
2. A useful but surprisingly brief description of the America and its descendants is found in Peter M. Bowers, Curtiss Aircraft 1907?1947 (Annapolis, MD: Naval Institute Press, 1979).
3. Gordon Swanborough and Peter M. Bowers, United States Navy Aircraft since 1911 (Annapolis, MD: Naval Institute Press, 1968), p. 106.
4. The aircraft would depart North America from St. John's, Newfoundland, with refueling stops at Fayal and San Miguel in the Azores, and terminate at Lisbon, Portugal.
5. The first H-16 built at the Naval Aircraft Factory made its first flight on 27 March 1918.
6. These aircraft were designated HS-1, HS-1L, and HS-2L. The letter "L" indicated aircraft fitted with Liberty engines.
The Second America