Curtiss 60 / A-12
Curtiss won a contract for five service test YA-8 (Model 59A) aircraft on 29 September 1931, and one YA-8 was reworked as the experimental YA-10 (Model 59B) with a 466kW radial engine.
The liquid-cooled Curtiss "Conqueror" engine was removed and replaced with a Pratt & Whitney air-cooled radial engine. The conversion was completed by September 1932 with comparable performance statistics to the original A-8 platform, and the aircraft was re-designated YA-10 because of the engine change.
All remaining A-8B's on order (some 46 total) with their Conqueror liquid-cooled engines were now changed to include the replacement Pratt & Whitney radial powerplant. The new production designation of A-12 (Model 60) was then assigned to mark these models. Though often designated with the "Shrike" name, the aircraft was formally known simply as the "A-12" in USAAC nomenclature. Shrike was an official Curtiss company name assigned to its A-12 product.
First appearing in 1933, these aircraft retained the open pilot's cockpit with faired headrest which had been introduced on the A-8 production batch, and carried the same machine-gun armament and bombload. In an attempt to improve co-operation between pilot and observer a major modification had been introduced, the rear cockpit being moved forward with its glazed covering forming a continuation of the fuselage decking immediately behind the pilot's cockpit.
An antenna structure rose high atop the fuselage, above and between the two cockpit positions. The pilot sat behind angled windscreens, complete a forward instrument panel and open sides revealing wiring, cables and piping. The fuselage itself was of tubular design and was made up of all-metal construction. With a fixed undercarriage with faired-over main landing gears - one positioned under each wing - and a conventional tail wheel, the wings were low-mounted monoplane assemblies with noticeable cable bracing and struts with slight dihedral. Wings were also of all-metal construction though the ailerons were covered over in fabric. The Wright R-1820-21 Cyclone radial piston engine of 690 horsepower powered a three-bladed propeller. Tail surfaces were also of all-metal construction but the rudder and elevator components were covered over in fabric.
Standard armament for the A-12 Shrike included a battery of 4 x .30 caliber machine guns in a fixed forward-firing set up with two guns fitted into each landing gear spat (600 rounds of .30 caliber ammunition allotted to each gun). A C-4 gunsight was afforded the pilot. The rear gunner had access to a .30 caliber machine gun on a flexible mounting to protect the aircraft's "six". Aside from the machine gun armament, the A-12 was cleared for light bombing duty and could field up to four 122lb conventional drop bombs under the wings. In place of these munitions, the Shrike could also utilize up to 10 x 30lb fragmentation bombs or flares for marking targets at night. A 52-gallon external fuel tank could be used in place of the bombs and could be jettisoned when empty. Interestingly enough, the main fuel tank aboard the A-12's fuselage could also be jettisoned via a hand crank.
The A-12 was delivered to the USAAC in 1933. Initial examples became a single production model and two service test aircraft. A-12's eventually made up the mount of choice for the 3rd Attack Group and 37th Attack Squadron of the 8th Pursuit Group. The aircraft was eventually shipped off the mainland and ended up in Hawaii via Wheeler Field and then later at Hickam Field. Incidentally, Hickam Field itself was named after Lieutenant Horace Meek Hickam whom died while attempting to land his A-12 Shrike at Fort Crockett in Texas.
Operationally, the A-12 was never used in anger by American forces. Though nine A-12s still remained in service at the attack on Pearl Harbor, the aircraft never went airborne in defense of the island and the type was dropped from service soon afterwards. A-12's maintained a limited capacity as reconnaissance platforms as well and could be modified for the role through the use of onboard cameras.
The Chinese nationalist government bought at least 20 of an export version of the A-12 in 1936. These A-12's sported a more powerful version of the air-cooled engine in the Wright SR-1820F-52 of 775 horsepower supplying a better maximum speed of 182 miles-per-hour. These saw some action against the Japanese in 1937-8.
Some A-12's underwent further periods of notable development. One such conversion involved the addition of ski-like implements in place of the landing gear fairings to make the A-12 more "bad-weather friendly". Not only did this allow the Shrike to operate from icy or snowbound airstrips, it provided for viable landings and take-off operations from dirt, grass and paved-over runways as well. Another such development involved adding inflatable air bladders to the sides of the fuselage. Should the crew and aircraft be forced into an emergency landing over water, the air bladders could be filled to allow the A-12 to stay above water until help arrived. These implements were never put into production A-12s.
Curtiss A-12 (Shrike)
Engines: 1 x Wright R-1820-21 Cyclone radial, 690 hp (515-kW)
Length: 32 ft 3 in (9.83m)
Wing span: 44 ft 0 in (13.41m)
Wing area 284.0 sq ft (26.38 sq.m)
Height: 9 ft 4 in (2.84m)
Maximum Speed: 177mph (285kmh; 154kts) at sea level
Maximum Range: 521miles (838km)
Service Ceiling: 15,157ft (4,620m)
Iinitial climb rate: 1170 ft (357 m) per minute
4 x .30 caliber machine guns in fixed-forward positions.
1 x .30 caliber machine gun in rear flexible mounting.
4 x 122lb bombs
10 x 30lb fragmentation bombs
1 x 52 gallon external fuel droptank
Empty Weight: 3,898lbs (1,768kg)
Maximum Take-Off Weight: 5,756lbs (2,611kg)