Airborne (1997) (31 page)

A Fairchild Republic A-10A “Warthog” in flight. This heavily armed and armored aircraft is the backbone of the U.S. Air Force’s Close Air Support force.

Just one little problem, though, and that was that the Congress and U.S. Army expected (and forced) the USAF to build a “real” CAS airplane for use in the 1970s. Grudgingly, the USAF complied with the mandate and started the A-X (Attack Experimental) program to accomplish that task as cheaply and quickly as was possible. When the competition for a new A-X prototype was initiated, a number of aircraft companies submitted designs to the USAF for consideration. Two finalists were selected, and in 1972 a fly-off between Northrop’s YA-9A and Fairchild-Republic’s YA-10A was conducted. Northrop’s conventional design was more maneuverable, but Fairchild’s entry was judged to be more survivable in a “high-threat” environment (such as the European Central Front or Korea). Some design changes to accommodate USAF wishes were added, and the first production aircraft were delivered in the spring of 1976. Production ended in the 1980s after 650 had been delivered. In late 1996, some 231 remained in service with the U.S. Air Force, the remainder having been retired into storage or lost operationally. Hopes for foreign sales to the Republic of Korea and Turkey never materialized, as much due to the superb marketing of the F-16 (which was sold as a competitor) as anything else. However, the type will remain in service, mostly with National Guard and Reserve units, well into the 21st century, thanks to the brilliant performance of the A-10 community in Desert Storm.

With our history lesson done for now, let’s have a look at the Warthog. WEFT: Wings, Engines, Fuselage, Tail. These are the four key features you memorize when studying aircraft recognition, and it is a good way to start examining the A-10. For at certain angles, the Hog is almost a dead ringer for the World War II-vintage B-25 Mitchell medium bomber that was used by Jimmy Doolittle’s Tokyo Raiders to bomb Japan. The Mitchell had a reputation for being one of the toughest, most survivable aircraft of the era, and those same qualities are at the core of the A-10’s design.

The A-10’s broad, thick, low-mounted wings are almost perfectly straight. The absence of wing sweep angle tells you right away that the A-10 is a subsonic design. The wingspan is 57 feet, 6 inches/17.53 meters, and the tips are rounded off with a graceful twist. This, by the way, is the last graceful thing you will see on the Warthog’s airframe. There is a stubby pod about mid-span on each wing, and the rubber tire sticking out in the airstream tells you that this is the fairing for the main landing gear. Each wing has five weapons stations: two inboard and three outboard of the main gear pods respectively. One of these, though, is usually removed to cut weight and drag. The big ailerons on the outboard trailing edge can split, above and below the wing, acting as dive brakes, or spoilers to shorten the landing roll. Unlike most aircraft, the A-10’s wings contain no internal fuel tankage where a stray AAA round or SAM fragment might set it off. To prevent explosions or fire, the armored and self-sealing fuel tanks are concentrated inside the fuselage, a compromise to the core design philosophy of the Warthog: survivability. Another concession in the A-10 design was that the plane would be designed with simplicity in mind. No “wiz-bang” avionics or systems would be carried, unless they supported the core mission of the Warthog: daylight CAS operations over the Forward Edge of Battle Area.

The twin engines are General Electric TF-34 turbofans mounted in cylindrical pods on short pylons extending up and outboard from the aft section of the fuselage. If one TF-34 is shot away, the A-10 can limp home on the other, as several Hogs did during Desert Storm. The TF-34 was chosen to save on development costs, since it was already in production for the Navy’s S-3 Viking, a carrier-based antisubmarine plane that needed long endurance and the ability to loiter at low-altitude.
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Aircraft designers hate putting a brand-new engine design on a new aircraft type, since experience teaches that this is a common source of development trouble. Each engine is rated at 9,065 1b/4112 kg of thrust, pretty anemic for an aircraft with a maximum takeoff weight of almost 50,000 lb/22,680 kg. Generally, the TF-34 lacks acceleration as well as thrust, and the A-10’s maximum speed at sea level is a modest 439 kn/813.5 kph. Most engines have some design margin for increased thrust during their life cycle, but there was never any money to soup up the TF-34. Turbofans are very fuel-efficient engines, but an equally important consideration for the A-10 is high “bypass ratio,” which mixes a lot of cool air with the hot turbine exhaust, reducing the aircraft’s vulnerability to heat-seeking missiles. Another benefit of the TF-34 is reduced noise; on the ground you cannot hear an A-10 flying above 5,000 feet/1500 meters of altitude.

The purpose of any warplane is to place ordnance onto targets, and the A-10’s design is a classic example of this philosophy. Since the Warthog’s primary mission is CAS, with a special emphasis on destroying heavy armored vehicles (like main battle tanks), the A-10 drew a lot on the lessons of the German JU-87G1 and Russian IL-2
Shturmovik.
The A-10’s narrow fuselage was designed around the huge armor-busting General Electric GAU-8 “Avenger” cannon. This is an externally powered seven-barrel rotary 30mm gun, almost 20 feet/6.1 meters long, weighing in at 4,029 1b/1831 kg. The GAU-8’s rotary gun mechanism is based on the 150-year-old Gatling design, but an ingenious “linkless” ammunition-conveyor system makes it possible to fire at a cyclic rate of fifty to seventy rounds per second! Each barrel is 7 feet six inches/2.3 meters long (or to put it in ordnance terms, 76.66 calibers), and the entire GAU-8 system is about the size of a Volkswagen Beetle compact car!
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Viewed from the front, the gun muzzle appears offset slightly to port, giving the nose a peculiar asymmetry, but as the gun assembly rotates, the barrel exactly on the centerline is the one that fires.

The GAU-8 gives the Warthog awesome firepower against ground targets, unlike anything seen since the end of World War II. However, with a magazine capacity of only 1,350 rounds, A-10 pilots must fire short bursts. The standard combat load is a mix of armor-piercing (AP) and high-explosive-incendiary (HEI) shells. The AP round can pierce the top or side armor of most heavy tanks, and in wartime, the A-10 would use depleted-uranium AP projectiles. This is a very dense metal that ignites and burns violently when compressed and heated by a high-velocity impact. “Depleted” uranium has had most of its fissionable U-235 removed, and thus has only a tiny residual radioactivity, but like most other heavy metals it is quite toxic. So, in consideration of environmental concerns, it is being replaced by tungsten alloy projectiles. However you look at it, the GAU-8 “main battery” of the A-10 is an impressive weapon.
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Survivability was at the core of the original A-X specification, and was one of the reasons that Fairchild won the contract. Since most of the aircraft that were lost in Vietnam had been shot down by light AAA fire, the Warthog was specifically hardened against this threat. In the forward fuselage is a “titanium bathtub” surrounding the cockpit to protect the pilot and flight controls. Light as aluminum and stronger than steel, titanium is very difficult to cast or weld, which makes it an expensive luxury in aircraft structures. But the A-X specification required protecting the pilot from cannon shells up to 23mm in caliber, and steel armor would have been far too heavy. Other parts of the Warthog have also been heavily overbuilt, so that they are “ballistically tolerant” to all sorts of different ordnance. This means that they will still function if hit by, say, a 7.62mm machine-gun round, or a fragment from an exploding surface-to-air (SAM) warhead. Virtually every assembly on the A-10 went through some type of ballistic tolerance design and testing, and the results have been proven in combat. To appreciate the toughness of this A-10, consider the experience of one Desert Storm A-10 pilot:

“They counted 378 holes in it.... All four shells from a four-round clip of 57mm hit me ... the right engine... had forty-five holes in it—it wasn’t developing full power but it was still running when I landed.... The right side below the cockpit had seventeen major holes in it and the bathtub had a lot of chinks in it....” The aircraft was eventually patched up and flew home to Louisiana!

This pilot’s experience was hardly unique. Other Warthog drivers had their own battle damage experiences during Desert Storm, and usually their “Hogs” brought them safely home to fly and fight another day.

In addition to making the shell of the Warthog’s cockpit tough, the Fairchild-Republic designers made what is inside tolerant to the evils of the CAS environment. In addition to the standard ACES-series ejection seat, the A-10’s cockpit is packed with conventional round instrument dials (humorously called “steam gauges”) rather than the sleek multi-function displays (computer screens) found in contemporary pointy-nosed fast movers like the F-16. Mechanical instruments are far more resistant to shock and other unpleasant effects that the CAS environment commonly throws at your average Hog driver, and thus are the readouts of choice. The one exception to this rule is a small video display where the pilot can view the scene through the electro-optical or infrared seeker head of a selected AGM-65 Maverick missile.

Like everything else on the Hog, the controls on the A-10 are utterly conventional. A normal-looking control stick between the pilot’s legs and a twin throttle console on the left tell you that this is not one of the sexy “fly-by-wire” fighters like the F-16 or F-18. One unusual control is a lever that engages “manual reversion” of the flight controls, if both hydraulic systems are knocked out.
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This allows the pilot to fly the aircraft with pure muscle power through cables and pulleys, which can be an exhausting struggle in rough weather. Perhaps the one modern feature of the Hog’s cockpit is the bubble canopy, which gives the pilot a superb view of the battlefield, a vital necessity for CAS/FAC operations.

The outside of the A-10 appears to be randomly festooned with all variety of lumps and bumps. Each item, though, is designed to add to the functionality of the A-10 in CAS operations. Above the gun and forward of the bubble canopy is a receptacle for in-flight refueling from USAF tankers. In combat, A-10 squadrons will usually be based as close to the front line as possible, but in-flight refueling makes it possible for units based in the United States to carry out grueling marathon flights (thirteen hours or more) to deploy nonstop to remote overseas trouble spots. There is no room inside the nose for any kind of radar, but there is a pylon on the starboard forward fuselage for a laser-spot target seeker, the AAS-35 Pave Penny pod. While unable to project a laser spot to designate targets for laser-guided weapons itself, the Pave Penny can detect the laser spots from other designators, providing a steering cue to the pilot. This allows the Warthog driver to attack a target marked by troops on the ground with a designator, or by an airborne designator from a helicopter (like the Army OH-58D or Marine AH-1W) or other aircraft (such as an F-15E or F-16C with LANTRIN pods). This is only done rarely, as the A-10’s weapons load is mostly made up of unguided iron and cluster bombs, as well as fire-and-forget AGM-65 Maverick air-to-ground missiles.

Although the numerous underwing hardpoints can accommodate almost any kind of ordnance owned by the USAF, you won’t find much hanging here that is guided. The sexier and more expensive Paveway-series laser-guided bombs (LGBs) or the GBU-15/AGM-130-series electro-optical guided bombs and missiles are reserved for the supersonic members of the USAF Air Combat Command (ACC).
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The Warthog community views its primary weapons as the mighty GAU-8 gun, unguided bombs (like the Mk 80-series “iron” bombs, and CBU-87/89/97ries cluster weapons), 2.75-in/ 70mm rockets, and the AGM-65 Maverick AGM. Currently, the Imaging Infrared (IIR) -D and -G versions are the favorites, given their excellent seeker heads (which use the thermal signature of a target to home in on) as well as their large warheads. In fact, because the Maverick’s seeker head is based upon a staring matrix array of infrared detectors, as opposed to a single detector element like the AIM-9 Sidewinder air-to-air missile (AAM), it actually “sees” an image of the target. This image is fed onto the cockpit display screen we mentioned earlier, so that it can be used to “lock” the seeker head of the missile onto a target.

During Desert Storm, Warthog crews found that they could power up an IIR Maverick on the rail (A-10s usually carry two or three AGM-65s on each of a pair of three-rail launchers), and use the seeker as a “poor man’s” thermal imager or forward-looking infrared (FLIR) scanner. Given this rudimentary capability, Hog drivers were able to develop night intruder tactics for operations after dark.