A-10 Thunderbolt II
The A-10 Thunderbolt II is a United States Air Force attack aircraft, heavily armored, with a built-in antitank gun, low speed, and long endurance. Its designation has been changed to Thunderbolt, presumably with little risk of confusion with the highly successful fighter of the Second World War, the P-47 Thunderbolt.
Essentially, it is the antithesis of the traditional USAF model of the fighter, but an excellent close air support and battlefield air interdiction aircraft appreciated by ground troops. Its fundamental design derives from the WWII Soviet Il-2 Stormovik, and has some similarity with the current Russian Su-25 (NATO designation FROGFOOT). Its P-47 ancestor did have considerable air-to-air capability, but, with the introduction of the P-51 Mustang, found itself even more preferred in air-to-ground roles.
The modern Thunderbolt can loiter for long periods over the battlefield, and fly low, slow, and accurately when cooperating with ground troops. With operational experience, it has been found that the A-10 is complementary to the AH-64 Apache attack helicopter and OH-58 Kiowa Warrior scout armed helicopter. It can also communicate with high-performance fighter-bombers such as the F-16 Fighting Falcon.
While it officially is called the Thunderbolt (II), as what may be the ugliest aircraft in the history of the USAF, if not military aviation, it is known as the Warthog. That name is used with great respect by the ground troops it supports.
The A-10 can survive much more battle damage than other aircraft, but it is marginally, at best, effective when the opponent has modern air defense. Experience in the Gulf War, as well as in simulated NATO-Warsaw Pact combat, showed that suppression of enemy air defense (SEAD) was necessary before the A-10's full capability was useful. For the close support environment for which it was optimized, one approach would be to cooperated with scout and attack helicopters, which would hover behind a hill or other terrain cover, then, as the A-10s came close, destroy low-level antiaircraft weapons such as the ZSU-23-4 mobile anti-aircraft artillery piece, as welland SA-6 GAINFUL and SA-8 GECKO surface-to-air missiles.
Attempts were made to retire it in favor of higher-performance Air Force airplanes, but it had established a niche. The OA-10 version provides fire direction as well as direct attack.
The A-10, however, is due to be replaced by the F-35A Lightning II, the USAF version of the F-35 Joint Strike Fighter. This aircraft, which also replaces the F-16, is a high-performance fighter-bomber, not a "low and slow" armored attack airplane.
First flown in May 1972,  Originally manufactured by Fairchild, since 1987 the prime contractor for the A-10 has been Northrop Grumman. A total of 707 were built, with 350 still in service with the regular Air Force, the US Air Force Reserve and the Air National Guard.
The basic design centered around the heaviest gun system, in terms of combined rate of fire and energy of projectiles, ever built for an aircraft. As large as a Volkswagen Beetle, the 30 mm GAU-8 fires 30 mm antitank rounds, typically made of depleted uranium.
The A-10 has an external load capacity of 7,260 kg. There are three pylons under the fuselage and the loads can be configured to use either the center-line pylon or the two flanking fuselage pylons. Where more standoff range is needed, it can carry up to ten AGM-65 Maverick air-to-surface missiles. When it needs self-defense, it can carry the AIM-9 Sidewinder air-to-air missile.
For weapon guidance, the aircraft can be fitted with Pave Penny laser guidance / electronic support measures, pod installed on the starboard fuselage pylon. Each wing carries four storage pylons, three outboard and one inboard of the wheel fairing.
Its pylons can carry a wide range of other munitions, including the Mk. 82 low-drag gravity bomb, BLU-1 and BLU-27/B Rockeye II cluster bombs, and the cluster bomb unit CBU-52/71.
A-10's use the Northrop Grumman Litening ER (Extended Range) targeting pod, which includes 640 x 512 pixel thermal imager, CCD TV, laser rangefinder, IR marker and laser designator. The pilot can wear night vision goggles and also look through the electro-optical imaging displays of the Maverick AGM-65.
At the heart of the electronic defense system is the AN/ALR-69(V) improved radar warning receiver, which, at a basic level, can cue an AN/ALE-37 (or its ALE-47 replacement) to dispense expendable chaff, flares, and disposable jammer cartridges. It can also direct the AN/ALQ-131 multifunction jammer pod. The A-10 also can use the AN/ALQ-184 pod, which can tow a non-cartridge, expendable AN/ALE-50 radar decoy pod.
Once the gun system was placed, other features were intended to increase survivability. The pilot sits in a titanium-armored "bathtub", which has a large bulletproof bubble canopy, for good all-round vision.
The cockpit is equipped with a head-up display, for targeting and weapon aiming, a HAVE QUICK II secure radio communications system, inertial navigation and a tactical air navigation (TACAN) system. A-10s have two engines so they can fly back with one, and they are mounted above the horizontal stabilizer in the tail to avoid ground fire.
The aircraft can survive direct hits from armor-piercing and high explosive projectiles up to 23mm. Their self-sealing fuel cells are protected by internal and external foam. Manual systems back up their redundant hydraulic flight-control systems. This permits pilots to fly and land when hydraulic power is lost. 
In June 2007, Boeing was awarded a contract for the A-10 wing replacement program. Boeing will supply 242 replacement wing sets by 2018.  This involves the creation of three-dimensional models of the wing, which will serve as the basis for engineering the improvements.
In addition to the LITENING ER (extended range) targeting pod, a number of A-10s have been equipped with embedded global positioning system (GPS)/inertial navigation system (EGI), which pinpoints the exact location of the aircraft. These aircraft are also to be fitted with BAE Systems Terrain Profile Matching systems (TERPROM). It is being equipped with the Joint Tactical Information Distribution System/Link 16 data links so it can network with other aircraft and ground sensors, including the E-8 Joint STARS ground surveillance radar aircraft.
An additional A-10 Thunderbolt Life-Cycle Program Support (TLPS) contract, to address multiple issues of keeping the aircraft in service, requires a contractor to "perform sustainment activities as directed by task order in the technical/functional areas of avionics, structures, mechanical systems, and software."
The aircraft has done well in the Gulf War, Balkans operations including Kosovo, and current operations in Afghanistan and Iraq. Even when the area of operations does not have tank targets, the A-10 remains a strong CAS aircraft. The upgraded A-10C reached initial operation capability in September 2007.
- Primary Function: A-10 -- close air support, OA-10 - airborne forward air control 
- Contractor: Fairchild Republic Co.
- Power Plant: Two General Electric TF34-GE-100 turbofans
- Thrust: 9,065 pounds each engine
- Wingspan: 57 feet, 6 inches (17.42 meters)
- Length: 53 feet, 4 inches (16.16 meters)
- Height: 14 feet, 8 inches (4.42 meters)
- Weight: 29,000 pounds (13,154 kilograms)
- Maximum Takeoff Weight: 51,000 pounds (22,950 kilograms)
- Fuel Capacity: 11,000 pounds (7,257 kilograms)
- Payload: 16,000 pounds (7,257 kilograms)
- Speed: 420 miles per hour (Mach 0.56)
- Range: 800 miles (695 nautical miles)
- Ceiling: 45,000 feet (13,636 meters)
- Armament: One 30 mm GAU-8/A seven-barrel Gatling gun; up to 16,000 pounds (7,200 kilograms) of mixed ordnance on eight under-wing and three under-fuselage pylon stations, including 500 pound (225 kilograms) Mk-82 and 2,000 pounds (900 kilograms) Mk-84 series low/high drag bombs, incendiary cluster bombs, combined effects munitions, mine dispensing munitions, AGM-65 Maverick missiles and laser-guided/electro-optically guided bombs; infrared countermeasure flares; electronic countermeasure chaff; jammer pods; 2.75-inch (6.99 centimeters) rockets; illumination flares and AIM-9 Sidewinder missiles.
- Crew: One
- Unit Cost: Not available
- Initial operating capability: A-10A, 1977; A-10C, 2007
- Inventory: Active force, A-10, 143 and OA-10, 70; Reserve, A-10, 46 and OA-10, 6; ANG, A-10, 84 and OA-10, 18
- "A-10 Thunderbolt (Warthog) Ground Attack Aircraft, USA", AirForceTechnology.com
- "A-10/OA-10 Thunderbolt II", Air Force Link
- Air Force Materiel Command, United States Air Force (June 30, 2008), Thunderbolt Life-cycle Program Support (TLPS), Solicitation Number: FA820208R1000