Northrop YA-9: Difference between revisions

The A-9 was a shoulder-wing [[monoplane]] of all-riveted [[aluminum alloy]] construction, with [[honeycomb structure]]s and [[Chemical milling|chemically milled]] skins. The required twin turbofans were fitted in nacelles under the aircraft's wing roots.{{#tag:ref|By comparison, the A-10 engine location at the tail is less conventional, but offers greater survivability in the case of a hit on the engine area. The double tail of the A-10 also hides the engine infrared and noise signature, and incorporates redundancy in case one of the tails is shot away.{{cn|date=January 2022}}|group=lower-alpha}} Northrop selected the {{convert|7200|lbf|kN|abbr=on}} [[Lycoming YF102]] engine for the YA-9 rather than the more powerful ({{convert|9280|lbf|kN|abbr=on}}) [[General Electric TF34]] used by the A-10, although either engine could be accommodated. The YF102 engine was a new design, based on the [[Avco Lycoming T55|T55]] [[turboshaft]] that powered the [[Boeing CH-47 Chinook|CH-47]] helicopter, which was selected in order to minimize costs.{{sfn|Jesse|Engbrecht|1996|p=58}}{{sfn|Aviation Week|1972|p=109}} The aircraft had a large cruciform [[Stabilizer (aeronautics)|stabilizer]] in order to improve directional stability for low-level flight. Split [[aileron]]s were fitted that could be used as [[Air brake (aeronautics)|airbrake]]s. When these airbrakes were operated asymmetrically in conjunction with the aircraft's [[rudder]], sideways control forces could be applied (and the aircraft moved sideways) without [[Aircraft principal axes#Vertical axis .28yaw.29|yawing]] or [[Banked turn|banking]], easing weapon aiming.{{sfn|Jesse|Engbrecht|1996|p=58}}{{sfn|Fink|1972a|pp=45–46}}

The pilot sat under a large bubble canopy well ahead of the leading edge of the wings. The cockpit was surrounded by a bathtub of armor (aluminum in the prototypes, which would have been replaced by [[titanium]] if production occurred) while the wing-mounted fuel tanks were self-sealing and filled with foam to minimize the potential for fires or massive fuel loss. Dual redundant hydraulic flight control systems were fitted, with a further manual backup to prevent a single hit from causing control failure. These design features were hoped to reduce combat losses by as much as 90% in Vietnam-type operations.{{sfn|Jesse|Engbrecht|1996|p=58}}{{sfn|Aviation Week|1972|p=113}} A single 30 mm [[Gatlingrotary guncannon]] was to be fitted in the belly of the aircraft, with the gun barrels extending under the nose. As the gun was mounted on the aircraft's centerline, the undercarriage nosewheel was offset {{convert|1|ft|m|spell=in}} to the left. As the [[GAU-8 Avenger]] cannon was not ready, both the YA-9 prototypes (as well asand the two YA-10s) were instead fitted with the smaller 20 mm [[M61 Vulcan]] instead. Ten underwing [[hardpoint]]s were fitted, allowing up to {{convert|16000|lb|kg|abbr=on}} of weapons, including bombs and [[AGM-65 Maverick]] [[air-to-ground missile]]s, to be carried.{{sfn|Jesse|Engbrecht|1996|p=59}}