Everything about A-10 Thunderbolt Ii totally explained
The
A-10 Thunderbolt II is an
American single-seat, twin-engine
jet aircraft developed by
Fairchild-Republic for the
United States Air Force to provide
close air support (CAS) of ground forces by attacking
tanks,
armored vehicles, and other ground targets, also providing a limited
air interdiction role. It is the first U.S. Air Force aircraft designed exclusively for close air support.
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. However, the A-10 is more commonly known by its nickname "Warthog" or simply "Hog".
Development
Criticism that the U.S. Air Force didn't take close air support 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 Huey 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. The
F-4 Phantom was pressed into close air support, but usually in emergencies, as its high cruising speed and fuel consumption hindered its ability to loiter, and the lack of a gun on most F-4 variants coupled with the relative ineffectiveness of the standard 20mm Vulcan round against hard targets made strafing runs either ineffective or impossible.
On
6 March 1967, the U.S. Air Force released a request for information to 21 companies. Their objective was to create a design study for a low-cost attack aircraft designated A-X, or "Attack Experimental". The officer in charge of the project was Col. Avery Kay.
One experimental two-seat A-10 Night Adverse Weather (N/AW) version was built by converting an A-10A. The Night Adverse Weather (N/AW) aircraft was developed by Fairchild from the first Demonstration Testing and Evaluation (DT&E) A-10 for consideration by the USAF. It included a second seat for a weapons officer responsible for ECM, navigation, and target acquisition. The variant was canceled and the only two-seat A-10 built now sits at Edwards Air Force Base awaiting a spot in the Flight Test Historical Foundation museum. The proposed two-seat A-10 trainer aircraft didn't go into production, as it was felt that the A-10 was simple enough to fly that a trainer version wouldn't be required.
The decision to make the 30 mm
GAU-8 gun the main anti-tank weapon of the A-10 was influenced by Vietnam A-1 pilots and by
Hans-Ulrich Rudel and his book, "Stuka Pilot". In World War II, Rudel flew the
Ju 87G Stuka and destroyed many tanks using its two underwing 37 mm guns. His book was required reading for members on the A-X project. The JU-87G was an outmoded airframe with ersatz anti-tank weapons attached, yet still inflicted impressive casualties on Soviet tank forces.
A-10s were initially an unwelcome addition to the arsenal in the eyes of Air Force brass. The Air Force prized the high-flying, high-performance
F-15 Eagle and
F-16 Fighting Falcon air-superiority jets, and were determined to leave the dirty work of close air support to Army
helicopters (the development of the
AGM-114 Hellfire anti-armor missile and
AH-64 Apache attack helicopter having since provided the Army with a viable anti-tank aircraft). Attempts to transfer the A-10 to the Army and the Marines were at first prevented by the 1948
Key West Agreement, and then by the A-10's impressive combat record during the
Gulf War in 1991. Shortly after the war, the Air Force gave up on the idea of replacing the A-10 with a close air support version of the F-16.
Upgrades
The A-10 has received many upgrades over the years. Aircraft were upgraded with
inertial navigation and a
Pave Penny laser sensor (marked target seeker) pod that allowed the pilot to detect laser energy for PID (Positive Identification) of an illuminated target. The Pave Penny is a passive seeker and can't self-designate a target for a Laser Guided Bomb (LGB). Later, the Low-Altitude Safety and Targeting Enhancement (LASTE) upgrade provided computerized weapon-aiming equipment, an autopilot, and ground-collision warning system. The A-10 is now compatible with
night-vision goggles for low-light operation. In 1999, aircraft began to receive
Global Positioning System navigation systems.
The A-10 is scheduled to stay in service with the USAF until 2028. Beginning in 2005, the entire A-10 fleet is being upgraded to the "C" model that will include improved
fire control system (FCS),
electronic countermeasures (ECM), and the ability to carry smart bombs. The A-10 will be part of a service life extension program (SLEP) with many receiving new wings. Modifications to provide precision weapons capability are well underway. Hill AFB has completed work on its 100th A-10 precision engagement upgrade in January 2008.
Design
The A-10 has superior maneuverability at low speeds and altitude, thanks to straight, wide wings with downturned "droop"
wing tips. These also allow short takeoffs and landings, permitting operations from rugged, forward airfields near front lines. The aircraft can loiter for extended periods of time and operate under 1,000 feet (300 m) ceilings with 1.5-mile (2.4 km) visibility. It typically flies at a relatively slow speed of 300 knots (345 mph or 555 km/h), which makes it a much better candidate for the ground-attack role than fast
fighter-bombers, which often have difficulty targeting small and slow-moving targets.
Engine exhaust passes over the aircraft's
horizontal stabilizer and between the
twin tails, decreasing the A-10's infrared signature and lowering the likelihood that the aircraft can be targeted by heatseeking missiles. The placement of the engines partially shields them from anti-aircraft fire behind the wings and tail.
The A-10 has integrally machined skin panels. Because the stringers are integral with the skin there are no join or seal problems. These panels, fabricated using computer controlled machining, reduce the man-hours and hence the cost of manufacture. The tests of war have shown that this type of panel is more battle-hardy. The skin isn't load-bearing, so damaged skin sections can be easily replaced in the field, with makeshift materials if necessary.
Most thin flat areas of the airframe are honeycomb panels. This is because thin honeycomb sandwich panels are less likely to deform in any direction than sheet metal panels even if part of the panel has been blown off or structurally compromised. Honeycomb panels of this type on the A-10 include the flap shrouds, the elevators, the rudders and other sections of the fins. The leading edge of the mainplane is honeycomb to provide strength with minimal weight compromise.
The
ailerons are at the far ends of the wings to gain greater
rolling moment as with most aircraft but there are two distinguishing features. First, the ailerons are larger than is typical, almost 50% of the
chord, providing improved control even at slow speeds. The aileron is also split, making it a
deceleron.
The Thunderbolt II can be serviced and operated from bases with limited facilities near battle areas. 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 ordnance load, allowing the aircraft to operate from damaged airbases. The aircraft is designed to be refueled, rearmed and serviced with minimal equipment. Operating from a forward area is both useful for close air support and necessary due to the A-10's relatively low cruise and top speeds.
Because of the close proximity of the front landing gear and the A-10's main cannon, the landing gear is offset to the aircraft's right and cannon slightly to the left (see schematic below). The offset front landing gear causes the A-10 to have dissimilar turning radii. Turning to the right on the ground takes less space than turning left.
Durability
The A-10 is exceptionally hardy. Its strong airframe can survive direct hits from armor-piercing and high-explosive projectiles up to 23 mm. The aircraft has triple redundancy in its flight systems, with mechanical systems to back up double-redundant
hydraulic systems. This permits pilots to fly and land when hydraulic power or part of a wing is lost. Flight without hydraulic power uses the manual reversion flight control system; this engages automatically for pitch and yaw control, and under pilot control (manual reversion switch) for roll control. In manual reversion mode, the A-10 is sufficiently controllable under favorable conditions to return to base and land, though control forces are much higher than normal. The aircraft is designed to fly with one engine, one tail, one elevator and half a wing torn off.
Self-sealing fuel tanks are protected by fire-retardant foam. Additionally, the main landing gear is designed so that the wheels semi-protrude from their
nacelles when the gear is retracted so as to make gear-up landings (
belly landing) easier to control and less damaging to the aircraft's underside. They also are all hinged toward the rear of the aircraft, so if hydraulic power is lost the pilot can simply drop the gear and a combination of gravity and wind resistance will open and lock the gear in place.
The cockpit and parts of the flight-control system are protected by of
titanium armor, referred to as a "titanium bathtub". The tub has been tested to withstand multiple strikes from 20 mm cannon fire. The thickness of the titanium varies from ½ an inch to 1½ inches determined by a study of likely trajectories and deflection angles. This protection comes at a cost, though; the armor plating itself weighs almost 6% of the entire aircraft’s empty weight. To protect the pilot from the fragmentation likely to be created from impact of a shell any interior surface of the tub that's directly exposed to the pilot is covered by a multi-layer
Kevlar spall shield. The canopy consists of a bullet-proof diffusion-bonded stretched-acrylic to withstand small arms fire and is resistant to spalling. The front windscreen offers shielding resistant to 20 mm cannon fire.
Recent proof of the durability of the A-10 was shown when USAF Captain (now Major)
Kim Campbell, flying a ground support mission over
Baghdad during the
2003 invasion of Iraq suffered extensive flak damage to her A-10. The hit damaged one of the A-10's two engines and crippled its hydraulic system, forcing the back-up mechanical system to operate the aircraft's stabilizer and flight controls. Despite this, the pilot managed to fly it for an hour and landed it safely at the air base in manual reversion mode.
Powerplant
There are several reasons for the unusual location of the A-10's General Electric TF34-GE-100 turbofan engines. First, the A-10 was expected to fly from forward air bases, often with semi-prepared substandard runways that presented a high risk of
foreign object damage to the engines. The height of the engines lowers the chance that sand or stones will enter the inlet. This also allows engines to remain running, allowing for shorter servicing and rearming turn-around times by ground crew. Servicing and rearming are further helped by having wings closer to the ground than would be possible if the engines were wing-mounted. The position also reduces the IR signature, which starts low anyway due to the engines' 6:1
bypass ratio. Because of their high position, the engines are angled upward nine degrees to bring the combined thrust line closer to the
aerodynamic center of the aircraft. This avoids trimming measures to counteract a nose-down pitching moment if the engines were parallel to the fuselage. The heavy engines require strong supports, so their pylons are connected to the airframe by four bolts.
All four fuel tanks are near the center of the aircraft, reducing the likelihood that that'll be hit or separated from the engines. The tanks are protected by several measures. The tanks are separate from the fuselage and so projectiles would need to penetrate the skin before reaching the tank. The refueling system is purged after use so that there's no fuel unprotected anywhere in the aircraft. All pipes self-seal if they're compromised. Most of the fuel system components are inside the tanks so that if a leak were to occur from the component the fuel wouldn't be lost. If a tank does get damaged, check valves ensure that fuel doesn't flow into the compromised tank. Most importantly, reticulated polyurethane foam lines both the inner and outer sides of the fuel tanks, holding debris and restricting fuel spillage in the event of damage. The other source of possible combustion, the engines, are shielded from the fuel system and the rest of the airframe by firewalls and fire extinguishing equipment.
Weapon systems
Although the A-10 can carry considerable disposable stores, its primary built-in weapon is the 30 mm
GAU-8/A Avenger Gatling gun. One of the most powerful aircraft cannons ever flown, it fires large
depleted uranium armor-piercing shells. In the original design, the pilot could switch between two rates of fire: 2,100 or 4,200 rounds per minute. This was changed to a fixed rate of 3,900 rounds per minute. The cannon takes about half a second to come up to speed, so 50 rounds are fired during the first second, 70 or 65 rounds per second thereafter. The gun is accurate; it can place 80% of its shots within a 40-foot (12.4 meter) circle from 4,000 feet (1,220 meters) while in flight. The GAU-8 is optimized for a slant range of with the A-10 in a 30 degree dive.
The fuselage of the aircraft is built around the gun. For example, the nose wheel is offset to the right so that the gun's firing barrel at the 9 o'clock position is aligned on the aircraft's centerline. The early A-10s carried 1,350 rounds of 30 mm ammunition, but it was replaced by a 1,174 round drum
Operational history
The first unit to receive the A-10 Thunderbolt II was the
355th Tactical Training Wing, based at
Davis-Monthan Air Force Base, Arizona in March 1976. The first unit to achieve full combat-readiness was the 354th Tactical Fighter Wing at
Myrtle Beach AFB, South Carolina in 1978. Deployments of A-10As followed at bases both at home and abroad, including
England AFB, Louisiana,
Eielson AFB, Alaska,
Osan Air Base, Korea, and
RAF Bentwaters/
RAF Woodbridge, England. The 81st TFW of RAF Bentwaters/RAF Woodbridge operated rotating detachments of A-10s at four bases in Germany known as Forward Operating Locations (FOLs): Leipheim,
Sembach Air Base, Nörvenich, and Ahlhorn.
The A-10 saw combat for the first time during the
Gulf War in 1991, destroying more than 1,000 Iraqi tanks, 2,000 military vehicles, and 1,200 artillery pieces. A-10s shot down two Iraqi helicopters with the
GAU-8 gun. A-10s had a mission capable rate of 95.7%, flew 8,100 sorties, and launched 90% of the
AGM-65 Maverick missiles fired in the conflict. Part of the reason for this success were the burning oil wells that provided Iraqi tanks some cover from advanced electronics and high-flying fighters like the F-15 and F-16, where the trained eye, longer gun range and stable gun platform of the A-10 proved its worth.
In the 1990s many A-10s were shifted to the
forward air control (FAC) role and redesignated OA-10. In the FAC role the A-10 is typically equipped with up to six pods of 2.75 inch (70 mm) Hydra rockets, usually with smoke or
white phosphorus warheads used for target marking. OA-10s remain fully combat capable despite the redesignation.
A-10s again saw service in the 1999
Kosovo War, in the later stages of the 2001
invasion of Afghanistan, in
Operation Anaconda in Afghanistan in March 2002 and in the
2003 Iraq war. In Afghanistan the A-10 is based at
Bagram.
On
30 April 2003,
USCENTAF issued Operation Iraqi Freedom: By the Numbers, a declassified report about the aerial campaign in the conflict. Sixty A-10s were deployed in Iraq; one was shot down near
Baghdad International Airport by Iraqi fire late in the campaign. Of the A-10s deployed, 47 were Air National Guard Aircraft, and 12 were from the Air Force Reserve. The A-10 had a mission capable rate of 85% in the war, and fired 311,597 rounds of 30 mm ammunition. The A-10 also flew 32 missions in which the aircraft dropped propaganda leaflets over Iraq.
The A-10C first deployed to Iraq in the third quarter of 2007 with the 104th Expeditionary Fighter Squadron. The jets include the Precision Engagement Upgrade.
The A-10 is scheduled to stay in service with the USAF until 2028 and possibly later, when it may be replaced by the
F-35 Lightning II.
Operators
The A-10 has been flown exclusively by the
United States Air Force and its Air Reserve Components, the
Air Force Reserve Command (AFRC) and the
Air National Guard (ANG). As of March 2008, 20 squadrons operate the A-10 or its OA-10 variant (nine USAF, six ANG, and five AFRC).
United States Air Force
Air National Guard
103d Airlift Wing - Bradley ANGB, Connecticut (BRAC 2005 removed aircraft, given C-21 in 2007)
104th Fighter Wing - Barnes ANGB, Massachusetts (BRAC 2005 saw unit transition to F-15C in 2007)
110th Fighter Wing - Battle Creek ANGB, Michigan(BRAC 2005 moves aircraft to 107th Fighter Squadron at Selridge ANGB, Michigan)
111th Fighter Wing - Willow Grove ARS, Pennsylvania (BRAC 2005 sees unit losing aircraft in 2012)
124th Wing - Boise Air Terminal, Idaho
175th Wing - Warfield ANGB, Martin State Airport, Maryland
188th Fighter Wing - Fort Smith, Arkansas (Transitioned from F-16s to A-10s due to BRAC 2005)
Air Force Reserve Command
442d Fighter Wing - Whiteman AFB, Missouri
917th Wing - Barksdale Air Force Base, Louisiana
926th Fighter Wing - NAS JRB New Orleans, Louisiana
A-10s on display
AeroWeb's A-10 List on Display
Specifications (A-10A)
Popular culture
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 this unique aircraft. 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 nicknamed "Superhog", and the Republic F-105 Thunderchief tagged "Ultra Hog". A less common nickname is the "Tankbuster".
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