P.Bowers Curtiss Aircraft 1907-1947 (Putnam)
Other Experimental Flying-boats
Several other flying-boats were built immediately after No.2 to try different hull designs, engine positions and other features. They carried no known designations and their constant modifications have complicated the identification problem. Three are described here.
Freak Boat/C-1/AB-1. Identified only as 'Freak Boat' in later Curtiss photographic records, this 'boat had a full-length hull but the pilots were in the open as on the standard hydro. The close gap of the equal-span wings lowered the upper wing to the top of the pusher engine. The horizontal tail was mounted on struts above the hull and the square rudder was used without a vertical fin.
After extensive modification that included entirely new tail surfaces and shorter unequal-span wings, this 'boat was sold to the Navy in November 1912, and designated C-1. In March 1914, the designation was changed to AB-1. As C-1, it made the first successful catapult launch of a flying-boat on 12 December, 1912, at Washington Navy Yard. Its last flight was on 1 April, 1914.
Tadpole. Identified only as Tadpole, this flying-boat is representative of several that had their hulls built in the form of elongated main hydro floats with the area between the top of the float and the wings built up with a light fabric-covered superstructure. On Tadpole, the tail surfaces were carried above the hull on struts. The wing assembly pivoted about the rear spar to provide a variable-incidence feature; the pusher engine was stabilized by a tie rod between the end of the propeller shaft and the tail surfaces.
A-2/OWL/E-1/AX-1. The A-2 was the Navy's second aeroplane, a Curtiss Model E delivered as a landplane on 13 July, 1911. The original engine was a four-cylinder 50 hp model, soon changed to a 60 hp V-8.
The A-2 was converted to a seaplane in June 1912. It was further modified at Hammondsport in October 1912 to enclose the crew in a fabric-covered superstructure between the float and the wings, eliminating the interchangeability feature and making the A-2 a short-hull flying-boat. Further experimentation added retractable wheels to give amphibian capability; the unofficial designation of OWL was applied to signify operation 'over water and land'. The Navy designation was changed to E-1 in September 1913 and finally to AX-1 in March 1914. It was wrecked on 27 November, 1915, after 91 flights.
Testing of the experimental flying-boats of 1912 soon resulted in a marketable design. The earliest production versions, which were undesignated, had hulls with strong lower structure and a light upper superstructure filling the underwing gap and enclosing the two-man crew. Wings, with interplane ailerons, were sometimes of equal span and sometimes had extended upper wingtips. The design culminated in the Model F, which was immediately popular and enjoyed wide sale to private owners in the United States and to foreign governments.
G.Swanborough, P.Bowers United States Navy Aircraft Since 1911 (Putnam)
The A-2 was delivered to the Navy on July 13, 1911, in landplane configuration. As a seaplane, it remained in the air for 6 hr 10 min on October 6, 1912. By October 1912, the A-2 had been converted to a flying-boat by the simple expedient of building a superstructure from the pontoon deck upward to enclose the crew. Retractable tricycle landing gear similar to that of the Triad was fitted, and the designation of the modified machine was changed to E-1. This was also called the OWL for Over Water and Land and was briefly known as the AX-1.
The next two Navy aeroplanes, designated A-3 and A-4 were also single-float Curtiss pushers with minor differences in detail. A-3 achieved a degree of fame on June 13, 1913, by establishing an American seaplane altitude record of 6,200 ft. By the time the Navy was ready to order additional Curtiss pusher seaplanes, the designation system had been changed and the aeroplanes were known as AH for Airplane, Hydro, followed by a sequence number. The first two procured under the new system were AH-8 and AH-9, both of which were referred to as Type AH-8 in the manner of naval ships, where the first of a new class or design gave its name to the entire group. The AH-8s were followed by five more, starting with AH-11. These were followed by a further three that Navy records refer to as AH-8 type.
Further designation changes took place within the procurement period of the Curtiss pushers, the last 11 being ordered under a system whereby each Navy aeroplane was identified by a consecutive serial number, which was prefixed by the letter A-for-Airplane. The Navy had wisely decided to designate its aeroplanes by the manufacturer's own name and model number, but since the Curtiss aircraft had no firm number at the factory, the remaining 11 of the basic design (A60-A62, A83-A90) were again designated as Type AH-8. A83 was the AH-9 rebuilt, and A84-A90 may have been similarly reassigned.
The original AH-8, meanwhile, had been turned over to the US Army. It survived World War I, still in Army hands, and was put in storage. It was resurrected in 1928 and flown briefly by Capt Holden C. Richardson, Chief of Design and Materiel Division, Bureau of Aeronautics, and Naval Aviator No. 13, on February 10.
The A-2, flown 575 times before becoming the E-1, had an 80 hp engine eventually, earlier units rated at 60 hp and 75 hp being fitted. Span, 37 ft 1 in; length, 27 ft 2 in; gross weight, 1,547lb; speed 60 mph.