Curtiss A-8 Shrike
The Curtiss A-8 Shrike was a two-seat ground-attack aircraft built by the Curtiss Aeroplane and Motor Company for the U.S. Army Air Corps. Designed in 1930 and first flown in June 1931, it was Curtiss's first all-metal military monoplane, with full-span leading-edge slats and trailing-edge flaps, though its wing was still wire-braced and its two cockpits stood far apart. Only a prototype and thirteen service-test aircraft were built, and eleven of the test aircraft were redesignated A-8 after trials. The Army's production order for 46 A-8Bs was instead filled by the radial-engined A-12, after the YA-10 trial showed an air-cooled radial better suited to the attack role.
Why It Mattered
The A-8 was Curtiss's answer to a U.S. Army Air Corps requirement, framed in 1930, for a new two-seat ground-attack aircraft. It broke with everything the company had built for the military before: Curtiss's first military monoplane, its first all-metal design, drawn with full-span leading-edge slats, enclosed cockpits and a streamlined undercarriage. When it reached squadrons in 1932, every other standard Air Corps aircraft was still a biplane, and Wikipedia describes its arrival as a sensation in American aviation circles. Yet only fourteen were ever built — one prototype and thirteen service-test machines — because the Army switched its production order to a radial-engined development, the A-12.
Design Notes
The A-8 was an all-metal, low-wing monoplane, but its wing was still braced with struts and wires, a practice History of War notes had last been seen on military monoplanes of the First World War. The wing carried automatic full-span leading-edge slats and trailing-edge flaps, advanced features for a new service type in 1931. Pilot and observer sat in tandem cockpits placed far apart, a layout History of War calls rather too widely separated; on the A-12 the rear cockpit was moved forward to close the gap. Power came from a 600 hp Curtiss V-1570 Conqueror, a liquid-cooled V-12 driving a fixed-pitch, three-bladed propeller. Armament was five .30-inch machine guns — four fixed in the undercarriage fairings and one flexible gun for the observer — and the fixed guns fired below the propeller arc, so they needed no synchronising gear. Beneath the wings, racks took up to 400 lb of bombs or chemical tanks.
Operational History
The prototype XA-8, Curtiss's Model 59, flew for the first time in June 1931, beat the rival General Aviation/Fokker XA-7 and won Curtiss an order for thirteen service-test aircraft. Five of the thirteen were completed as YA-8s and eight as Y1A-8s, the second batch bought with F-1 funds, a separate source of development money available to the Air Corps. The YA-8s, with Prestone-cooled V-1570-31 engines, entered Army service in June 1932; Wikipedia places the type with the 3rd Attack Group at Fort Crockett, Texas, from April that year. Testing split the small fleet into experiments: the first YA-8 became the YA-10 with an air-cooled Pratt & Whitney Hornet radial, and the last Y1A-8 became the Y1A-8A, with a geared 675 hp V-1570-57 engine and a revised wing. When testing ended, the remaining eleven aircraft — four YA-8s and seven Y1A-8s — were redesignated A-8, the only aircraft ever to carry that designation. The YA-10 trial settled the type's future: the radial aircraft was over 200 lb heavier and 8 mph slower, but the Air Corps judged the air-cooled radial better able to survive ground fire than a liquid-cooled engine, and replaced its order for 46 A-8Bs with 46 radial-engined A-12s.
Afterlife
Because none of the 46 A-8Bs on order was ever delivered, the A-8's whole service career was flown by the eleven redesignated test aircraft. The prototype XA-8 flew in the Army's 1933 exercises and was scrapped in March 1937. The design continued as the A-12, a development of the A-8 with the rear cockpit moved forward and a Wright Cyclone radial in place of the inline engine; all 46 were delivered during 1934. The A-12s remained in service until 1941, though in the 3rd Attack Group Northrop A-17s had taken over completely soon after the first of them arrived in February 1936. "Shrike" itself was Curtiss's own name for the aircraft, never an Army one, and Curtiss reused it for the A-10, A-12, A-14 and A-18 attack aircraft that followed.