The A-10 Thunderbolt II is an American twin-engine, straight wing jet aircraft developed by Fairchild-Republic in the early 1970s. It entered service in 1976, and is the only United States Air Force production-built aircraft designed solely for close air support, including attacking tanks, armored vehicles, and other ground targets.The A-10 Thunderbolt is also known as the Warthog, the 'flying gun' and the Tankbuster. The A-10 is a high-survivability and versatile aircraft, popular with pilots for the 'get home' effectiveness. The A-10 is suitable for operation from forward air bases, with short take-off and landing capability. The aircraft has a long range (800 miles), high endurance and can loiter in the battle area.
The manoeuvrability at low speed and low altitude (below 1,000ft) allows accurate and effective targeting and weapon delivery over all types of terrain. The aircraft was used extensively during Operation Desert Storm, in support of Nato operations in response to the Kosovo crisis, in Operation Enduring Freedom in Afghanistan and in Operation Iraqi Freedom.
The A-10 was designed around the 30 mm GAU-8 Avenger rotary cannon that is its primary armament. The A-10's airframe was designed for durability, with measures such as 1,200 pounds (540 kg) of titanium armor to protect the cockpit and aircraft systems, enabling it to absorb a significant amount of damage and continue flying. Its short takeoff and landing capability permits operation from airstrips close to the front lines, while its simple design enables maintenance at forward bases with limited facilities. The A-10A single-seat variant was the only version built, though one A-10A was converted to an A-10B twin-seat version. In 2005, a program was begun to upgrade remaining A-10A aircraft to the A-10C configuration.
The A-10's official name comes from the Republic P-47 Thunderbolt of World War II, a fighter that was particularly effective at close air support. The A-10 is more commonly known by its nicknames "Warthog" or "Hog". Its secondary mission is to provide forward air controller - airborne (FAC-A) support, by directing other aircraft in attacks on ground targets. Aircraft used primarily in this role are designated OA-10. With a variety of upgrades and wing replacements, the A-10's service life may be extended to 2028.
Development
Background
Criticism that the U.S. Air Force did not take close air support (CAS) seriously prompted a few service members to seek a specialized attack aircraft. In the Vietnam War, large numbers of ground-attack aircraft were shot down by small arms, surface-to-air missiles, and low-level anti-aircraft gunfire, prompting the development of an aircraft better able to survive such weapons. In addition, the UH-1 Iroquois and AH-1 Cobra helicopters of the day, which USAF commanders had said should handle close air support, were ill-suited for use against armor, carrying only anti-personnel machine guns and unguided rockets meant for soft targets. Fast jets such as the F-100 Super Sabre, F-105 Thunderchief and F-4 Phantom II proved for the most part to be ineffective for close air support because their high speed did not allow pilots enough time to get an accurate fix on ground targets and they lacked sufficient loiter time. The effective, but aging, Korean War era A-1 Skyraider was the USAF's primary close air support aircraft.
The first flight of the A-10 was in May 1972, and a total of 713 aircraft were produced. The production of A-10 aircraft came to an end in 1984. Originally manufactured by Fairchild, since 1987 the prime contractor for the A-10 has been Northrop Grumman, which carries out support and structural upgrade programmes from the Integrated Systems and Aerostructures Divisions at Bethpage, New York and at St Augustine in Florida.
Over 367 A-10 aircraft are in service with the US Air Force, Air Combat Command, the US Air Force Reserve and the Air National Guard. The aircraft variants currently in service in the US Air force are A-10 (143), and A-10C (70); Reserve A-10 (46) and OA-10 (6); ANG, A-10 (84) and OA-10 (18).
In June 2007, Boeing was awarded a $2bn contract for the A-10 wing replacement programme. Boeing will supply 242 replacement wing sets by 2018.
In September 2009, the US Air Force awarded two contracts worth $4.2m to Boeing for modernising its fleet of 365 A-10 Thunderbolt II aircraft for a period of three to 18 months. The contract was awarded as part of the total $1.6bn A-10 Thunderbolt life-cycle programme support (TLPS) contract.
The two contracts included A-10 Aircraft Structural Integrity Program (ASIP) which involves providing engineering services to the aircraft and upgraded data transfer unit (UDTU) which include trade study analysis and operational assessment / proof of concept. Both the contracts aim at upgrading the aircraft with avionics architecture to improve memory and data capability.
Design
Overview
The A-10 has superior maneuverability at low speeds and altitude because of its large wing area, high wing aspect ratio, and large ailerons. The wing also allows short takeoffs and landings, permitting operations from primitive forward airfields near front lines. The aircraft can loiter for extended periods and operate under 1,000 ft (300 m) ceilings with 1.5 mi (2.4 km) visibility. It typically flies at a relatively low speed of 300 knots (350 mph; 560 km/h), which makes it a better platform for the ground-attack role than fast fighter-bombers, which often have difficulty targeting small, slow-moving targets.
The leading edge of the wing has a honeycomb structure panel construction, providing strength with minimal weight; similar panels cover the flap shrouds, elevators, rudders and sections of the fins. The skin panels are integral with the stringers and are fabricated using computer-controlled machining, reducing production time and cost. Combat experience has shown that this type of panel is more resistant to damage. The skin is not load-bearing, so damaged skin sections can be easily replaced in the field, with makeshift materials if necessary. The ailerons are at the far ends of the wings for greater rolling moment and have two distinguishing features: The ailerons are larger than is typical, almost 50 percent of the wingspan, providing improved control even at slow speeds; the aileron is also split, making it a deceleron.
The A-10 is designed to be refueled, rearmed, and serviced with minimal equipment. Also, most repairs can be done in the field. An unusual feature is that many of the aircraft's parts are interchangeable between the left and right sides, including the engines, main landing gear, and vertical stabilizers. The sturdy landing gear, low-pressure tires and large, straight wings allow operation from short rough strips even with a heavy aircraft ordnance load, allowing the aircraft to operate from damaged airbases, flying from taxiways or even straight roadway sections.
The front landing gear is offset to the aircraft's right to allow placement of the 30 mm cannon with its firing barrel along the centerline of the aircraft. During ground taxi, the offset front landing gear causes the A-10 to have dissimilar turning radii. Turning to the right on the ground takes less distance than turning left. The wheels of the main landing gear partially protrude from their nacelles when retracted, making gear-up belly landings easier to control and less damaging. All landing gears are hinged toward the aircraft's rear; if hydraulic power is lost, a combination of gravity and wind resistance can open and lock the gear in place.
Cockpit
The single-seat cockpit is protected by all-round armour, with a titanium 'bathtub' structure to protect the pilot that is up to 3.8cm thick. The cockpit has a large bulletproof bubble canopy, which gives good all-round vision.
The cockpit is equipped with a head-up display, which is used for targeting and weapon aiming, a Have-Quick secure radio communications system, inertial navigation and a tactical air navigation (TACAN) system.
Lockheed Martin has begun delivery of 21 USAF A-10 aircraft with the embedded global positioning system / inertial navigation system (EGI), which pinpoints the exact location of the aircraft. The aircraft are also to be fitted with BAE Systems terrain profile matching systems (TERPROM).
The pilot is equipped with night-vision goggles and also the infrared imaging display of the Maverick AGM-65.
Weapons
The aircraft has 11 stores pylons, providing an external load capacity of 7,260kg. There are three pylons under the fuselage and the loads can be configured to use either the centre-line pylon or the two flanking fuselage pylons.
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 stores pylons: three outboard and one inboard of the wheel fairing.
The A-10 can carry up to ten Maverick air-to-surface missiles. The Raytheon Maverick AGM-65 missile uses a variety of guidance systems, including imaging infrared guidance and warheads, including a high-penetration, 57kg conical-shaped charge warhead. Range is more than 45km. The A-10 can also carry the Sidewinder air-to-air missile, which is an all-aspect short-range missile with maximum speed over Mach 2.
The A10 is capable of deploying a wide range of ordnance: for example, the LDGP mk82 226kg, 500lb general-purpose bombs, BLU-1 and BLU-27/B Rockeye II cluster bombs and the cluster bomb unit CBU-52/71.
The Northrop Grumman Litening ER (extended range) targeting pod has been successfully integrated on an A-10. Litening ER features a 640×512 pixel thermal imager, CCD TV, laser spot tracker / rangefinder, IR marker and laser designator.
The aircraft is armed with a General Dynamics GAU-8/A Avenger 30mm cannon, mounted in the nose of the aircraft.
Using the cannon, the A-10 is capable of disabling a main battle tank from a range of over 6,500m. The cannon can fire a range of ammunition, including armour-piercing incendiary rounds (API) weighing up to 0.75kg, or uranium-depleted 0.43kg API rounds.
The magazine can hold 1,350 rounds of ammunition. The pilot can select a firing rate of 2,100 or 4,200 rounds a minute.
Engines
The two non-afterburning turbo fan engines, TF34-GE-100, supplied by General Electric, each supply 9,065lb thrust. The location of the engines, high on the fuselage, allows the pilot to fly the aircraft fairly easily with one engine inoperable.
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| This A-10 suffered extensive damage during Operation Iraqi Freedom in 2003 |
The A-10 is exceptionally tough, being able to survive direct hits from armor-piercing and high-explosive projectiles up to 23 mm. It has double-redundant hydraulic flight systems, and a mechanical system as a back up if hydraulics are lost. Flight without hydraulic power uses the manual reversion control system; pitch and yaw control engages automatically, roll control is pilot-selected. In manual reversion mode, the A-10 is sufficiently controllable under favorable conditions to return to base, though control forces are greater than normal. The aircraft is designed to fly with one engine, one half of tail, one elevator, and half of a wing missing.
The cockpit and parts of the flight-control system are protected by 1,200 lb (540 kg) of titanium aircraft armor, referred to as a "bathtub". The armor has been tested to withstand strikes from 23 mm cannon fire and some strikes from 57 mm rounds. It is made up of titanium plates with thicknesses from 0.5 to 1.5 inches (13 to 38 mm) determined by a study of likely trajectories and deflection angles. The armor makes up almost 6 percent of the aircraft's empty weight. Any interior surface of the tub directly exposed to the pilot is covered by a multi-layer nylon spall shield to protect against shell fragmentation. The front windscreen and canopy are resistant to small arms fire.
The A-10's durability was shown on 7 April 2003 when Captain Kim Campbell, while flying over Baghdad during the 2003 invasion of Iraq, suffered extensive flak damage. Iraqi fire damaged an engine and crippled the hydraulic system, requiring the aircraft's stabilizer and flight controls to be operated via the 'manual reversion mode'. Despite this damage, Campbell flew the aircraft for nearly an hour and landed safely.
The A-10 was envisioned to fly from forward air bases and semi-prepared runways with high risk of foreign object damage to the engines. The unusual location of the General Electric TF34-GE-100 turbofan engines decreases ingestion risk, and allows the engines to run while the aircraft is serviced and rearmed by ground crews, reducing turn-around time. The wings are also mounted closer to the ground, simplifying servicing and rearming operations. The heavy engines require strong supports, four bolts connect the engine pylons to the airframe. The engines' high 6:1 bypass ratio have a relatively small infrared signature, and their position directs exhaust over the tailplanes further shielding it from detection by infrared homing surface-to-air missiles. The engines and their exhausts are angled upward by nine degrees to cancel out the nose-down pitching moment they would otherwise generate due to being mounted above the aircraft's center of gravity, avoiding the need to trim the control surfaces against the force.
To reduce the likelihood of damage to the A-10's fuel system, all four fuel tanks are located near the aircraft's center and are separated from the fuselage; projectiles would need to penetrate the aircraft's skin before reaching a tank's outer skin.[55][56] Compromised fuel transfer lines self-seal; if damage exceeds a tank's self-sealing capabilities, check valves prevent fuel flowing into a compromised tank. Most fuel system components are inside the tanks so that fuel will not be lost due to component failure. The refueling system is also purged after use. Reticulated polyurethane foam lines both the inner and outer sides of the fuel tanks, retaining debris and restricting fuel spillage in the event of damage. The engines are shielded from the rest of the airframe by firewalls and fire extinguishing equipment. In the event of all four main tanks being lost, two self-sealing sump tanks contain fuel for 230 miles (370 km) of flight.
Colors and markings
Since the A-10 flies low to the ground and at subsonic speed, aircraft camouflage is important to make the aircraft more difficult to see. Many different types of paint schemes have been tried. These have included a "peanut scheme" of sand, yellow and field drab; black and white colors for winter operations and a tan, green and brown mixed pattern. Many A-10s also featured a false canopy painted in dark gray on the underside of the aircraft, just behind the gun. This form of automimicry is an attempt to confuse the enemy as to aircraft attitude and maneuver direction. Many A-10s feature nose art, such as shark mouth or warthog head features.
The two most common markings applied to the A-10 have been the European I woodland camouflage scheme and a two-tone gray scheme. The European woodland scheme was designed to minimize visibility from above, as the threat from hostile fighter aircraft was felt to outweigh that from ground-fire. It uses dark green, medium green and dark gray in order to blend in with the typical European forest terrain and was used from the 1980s to the early 1990s. Following the end of the Cold War, and based on experience during the 1991 Gulf War, the air-to-air threat was no longer seen to be as important as that from ground fire, and a new color scheme known as "Compass Ghost" was chosen to minimize visibility from below. This two-tone gray scheme has darker gray color on top, with the lighter gray on the underside of the aircraft, and started to be applied from the early 1990s.
Future
In 2007, the A-10 was expected to be in USAF service until 2028 and possibly later, when it may be replaced by the Lockheed Martin F-35 Lightning II. Critics have said that replacing the A-10 with the F-35 would be a "giant leap backwards" given the A-10's performance and the F-35's rising costs. In 2012, the Air Force considered the F-35B STOVL variant as a replacement CAS aircraft, but concluded that the aircraft could not generate sufficient sorties. In August 2013, Congress and the Air Force examined various proposals, including the F-35 and the MQ-9 Reaper unmanned aerial vehicle filling the A-10's role. Proponents state that the A-10's armor and cannon are superior to aircraft such as the F-35 for ground attack, that guided munitions other planes rely upon could be jammed, and that ground commanders frequently request A-10 support.
In the USAF's FY 2015 budget, the service considered retiring the A-10 and other single-mission aircraft, prioritizing multi-mission aircraft; cutting a whole fleet and its infrastructure was seen as the only method for major savings. The U.S. Army had expressed interest in obtaining some A-10s should the Air Force retire them, but later stated there was "no chance" of that happening. The U.S. Air Force stated that retirement would save $3.7 billion from 2015 to 2019. Guided munitions allow more aircraft to perform the CAS mission, reducing the requirement for a specialized aircraft; since 2001, multirole aircraft and bombers performed 80 percent of CAS missions. The Air Force stated the A-10 is also more vulnerable to advanced anti-aircraft defenses. The Army stated that the A-10 is invaluable for its versatile weapons loads, psychological impact, and reduced logistics needs on ground support systems.
In January 2015, USAF officials told lawmakers that it would take 15 years to fully develop a new attack aircraft to replace the A-10; service leaders admit a follow-on weapon system for the A-10 is "on the table." It planned for F-16s and F-15Es to initially take up CAS sorties, and later by the F-35A once sufficient numbers become operationally available over the next decade. The service is considering purchasing a relatively inexpensive replacement to perform CAS against enemies that lack sophisticated air defenses. As of 2015, the US Air Combat Command is considering developing a replacement aircraft. In January 2016, the USAF revealed it was "indefinitely freezing" plans to retire the A-10 for at least several years. In addition to Congressional opposition, its use in anti-ISIL operations, deployments to Eastern Europe as a response to Russia's military intervention in Ukraine, and reevaluation of F-35 numbers necessitated its retention. Retirement has been deferred until 2022 when F-35s will begin replacing it on a squadron-by-squadron basis.
Nicknames
The A-10 Thunderbolt II received its popular nickname "Warthog" from the pilots and crews of the USAF attack squadrons who flew and maintained it. The A-10 is the last of Republic's jet attack aircraft to serve with the USAF. The Republic F-84 Thunderjet was nicknamed the "Hog", F-84F Thunderstreak nicknamed "Superhog", and the Republic F-105 Thunderchief tagged "Ultra Hog". The saying Go Ugly Early has been associated with the aircraft in reference to calling in the A-10 early to support troops in ground combat.
Variants
YA-10A
Pre-production variant. 12 were built.
A-10A
Single-seat close air support, ground-attack version. (All updated to A-10C)
OA-10A
A-10As used for airborne forward air control. (All updated to A-10C)
YA-10B Night/Adverse Weather
Two-seat experimental prototype, for work at night and in bad weather. The one YA-10B prototype was converted from an A-10A.
A-10C
A-10As updated under the incremental Precision Engagement (PE) program.
A-10PCAS
Proposed unmanned version developed by Raytheon and Aurora Flight Sciences as part of DARPA's Persistent Close Air Support program. The PCAS program eventually dropped the idea of using an optionally manned A-10.
Civilian A-10
Proposed by the South Dakota School of Mines and Technology to replace its North American T-28 Trojan thunderstorm penetration aircraft. The A-10 would have its military engines, avionics, and oxygen system replaced by civilian versions. The engines and airframe would receive protection from hail, and the GAU-8 Avenger would be replaced with ballast or scientific instruments.
Specifications (A-10A)
Data from The Great Book of Modern Warplanes, Fairchild-Republic A/OA-10, USAF
General characteristics
Crew: 1
Length: 53 ft 4 in (16.26 m)
Wingspan: 57 ft 6 in (17.53 m)
Height: 14 ft 8 in (4.47 m)
Wing area: 506 ft² (47.0 m²)
Airfoil: NACA 6716 root, NACA 6713 tip
Empty weight: 24,959 lb (11,321 kg)
Loaded weight: 30,384 lb (13,782 kg)
CAS mission: 47,094 lb (21,361 kg)
Anti-armor mission: 42,071 lb (19,083 kg)
Max. takeoff weight: 50,000 lb (23,000 kg)
Powerplant: 2 × General Electric TF34-GE-100A turbofans, 9,065 lbf (40.32 kN) each
Internal fuel capacity: 11,000 lb (4,990 kg)
Performance
Never exceed speed: 450 knots (518 mph, 833 km/h) at 5,000 ft (1,500 m) with 18 Mk 82 bombs
Maximum speed: 381 knots (439 mph, 706 km/h) at sea level, clean
Cruise speed: 300 knots (340 mph, 560 km/h)
Stall speed: 120 knots (138 mph, 220 km/h)
Combat radius:
CAS mission: 250 nmi (288 mi, 460 km) at 1.88 hour loiter at 5,000 ft (1,500 m), 10 min combat
Anti-armor mission: 252 nmi (290 mi, 467 km), 40 nmi (45 mi, 75 km)) sea-level penetration and exit, 30 min combat
Ferry range: 2,240 nmi (2,580 mi, 4,150 km) with 50 knot (55 mph, 90 km/h) headwinds, 20 minutes reserve
Service ceiling: 45,000 ft (13,700 m)
Rate of climb: 6,000 ft/min (30 m/s)
Wing loading: 99 lb/ft² (482 kg/m²)
Thrust/weight: 0.36
Armament
Guns: 1× 30 mm (1.18 in) GAU-8/A Avenger Gatling cannon with 1,174 rounds (Capacity 1,350)
Hardpoints: 11 (8× under-wing and 3× under-fuselage pylon stations) with a capacity of 16,000 lb (7,260 kg) and provisions to carry combinations of:
Rockets:
4× LAU-61/LAU-68 rocket pods (each with 19× / 7× Hydra 70 mm rockets, respectively)
4× LAU-5003 rocket pods (each with 19× CRV7 70 mm rockets)
6× LAU-10 rocket pods (each with 4× 127 mm (5.0 in) Zuni rockets)
Missiles:
2× AIM-9 Sidewinders air-to-air missiles for self-defense
6× AGM-65 Maverick air-to-surface missiles
Bombs:
Mark 80 series of unguided iron bombs or
Mk 77 incendiary bombs or
BLU-1, BLU-27/B Rockeye II, Mk20, BL-755 and CBU-52/58/71/87/89/97 cluster bombs or
Paveway series of Laser-guided bombs or
Joint Direct Attack Munition (A-10C) or
Wind Corrected Munitions Dispenser (A-10C)
Other:
SUU-42A/A Flares/Infrared decoys and chaff dispenser pod or
AN/ALQ-131 or AN/ALQ-184 ECM pods or
Lockheed Martin Sniper XR or LITENING targeting pods (A-10C) or
2× 600 US gallon Sargent Fletcher drop tanks for increased range/loitering time.
Avionics
AN/AAS-35(V) Pave Penny laser tracker pod (mounted beneath right side of cockpit) for use with Paveway LGBs (Currently the Pave Penny is no longer in use)
Head-up display (HUD) for improved technical flying and air-to-ground support.