The history and design behind the legendary A-10
We've all seen the memes. The A-10 Thunderbolt II, better known as the Warthog, has become the Internet's favorite warplane thanks in large part to its signature 'BRRRT' sound that it makes when it fires its massive 30mm gun. It's highly doubtful that the engineers at Fairchild Republic that designed the A-10 could have anticipated the legendary status that the aircraft they designed would achieve, let alone that it would still be flying, 50 years in the future. After all, while the A-10 was designed to take a beating, it was also designed to be cheap and easy to maintain.
There's no question the German Panzer tanks were the most thoroughly engineered and well-built tanks of WWII. However, this attention to detail would be their downfall. Because American and Soviet tanks like the M4 Sherman and T-34 were much simpler and cheaper to produce, the allied forces were able to flood the fields of Europe with armor and overwhelm the numerically inferior German tanks. In addition to this, the allies controlled the skies overhead which made German armor easy pickings for ground attack aircraft like the Republic P-47 Thunderbolt. The lessons learned through the evolution of warfare would be applied to the P-47s spiritual successor a few decades later in the Cold War.
Following the end of WWII and the creation of the Iron Curtain, the Western allies of NATO embarked on a massive military buildup in order to meet the potential threat of the Warsaw Pact forces. If the Cold War were to heat up, the biggest battleground where these two sides would meet would be the Fulda Gap. Located between the Hesse-Thuringian border and Frankfurt am Main, the Fulda Gap contains two corridors of lowlands that the Soviets would have had to push their armored forces through in order to reach and cross the strategically vital Rhine River. As a result, allied armor was built up heavily in this region. The anticipated battle also influenced weapons doctrine and development at the time.
In order to win a fight on the ground, you had to win the fight in the air. This concept was proven in WWII. While ground forces went toe-to-toe with the enemy, air forces flew behind enemy lines in order to strike logistical targets like supply convoys, factories, roads, and bridges. From this, the doctrine of AirLand Battle was born. It emphasized close coordination between land forces acting as an aggressively maneuvering defense and air forces attacking rear-echelon forces feeding the enemy's front-line forces. Picture divisions of M60 'Patton' Main Battle Tanks trying to hold off the onslaught of Soviet T-54 and T-54s coming through the Fulda Gap while B-52 Stratofortress bombers flew overhead to destroy the Soviet supply lines feeding their tanks. Without going too in depth, this is AirLand Battle in a nutshell.
Another lesson learned from WWII was that tanks were more effective when they worked in concert with close air support. Combined attacks by Sherman tanks and aircraft like the aforementioned P-47 spelled certain doom for German tanks. In order to carry this concept into the Cold War, the United States developed aircraft to fill the CAS role. While the Army was given the AH-64 Apache to kill tanks from the air, the Air Force was given the A-10 Lightning II.
Built by the same company that built the P-47 Thunderbolt (Republic Aviation was acquired by Fairchild Aircraft in 1965 to create Fairchild Republic), the Lightning II was the Fairchild Republic submission to the Air Force's 1966 A-X aircraft program to acquire a low-cost attack aircraft. In 1970, the Air Force issued a more detailed request for proposals to the program including the mandate that the aircraft be equipped with a 30mm rotary cannon. On January 18, 1973, after a series of tests and trials, the Air Force announced that Fairchild Republic's submission was selected and would enter production as the A-10. The new aircraft would be equipped with the GAU-8 30mm cannon which would be built by General Electric who won their own government contract in June of the same year.
The A-10 was designed to engage enemy armor in close proximity to friendly forces from very low altitude. In order to deliver precision fires and avoid hitting friendly forces, the A-10 was designed to be slow but tough. Its most important component, the pilot, is protected underneath by a titanium tub capable of withstanding armor-piercing and high-explosive rounds up to 23mm in caliber. The canopy, while not as strong, is made of ballistic glass and is capable of resisting small-arms as well as shrapnel from AA fire and missiles to a certain degree. The fuel tanks are separated from the fuselage to reduce the likelihood of damage. The fuel system is also self-sealing and lined with a reticulated polyurethane foam both inside and outside. In the event that all four main tanks are depleted, the A-10 is equipped with two self-sealing sump tanks that contain enough fuel for 230 miles of flight.
The tail of the A-10 bears a striking resemblance to WWII-era level bombers. This unusual design increases stability, like it did for those bombers, making the A-10 a very stable gun platform. This attribute is critical for a CAS aircraft. The tail also helps to mask the heat signature of the top-mounted engines. Though its twin GE TF34 turbofan engines produce just over 41 kN of thrust each (compared to the F-15 Eagle's original Pratt Whitney F100 engines which produced over 100 kN of thrust each), the aircraft is capable of flight with just one engine. Similarly, the hydraulic flight systems are both double-redundant and are equipped with a manual backup system if both hydraulic systems fail. In all, the A-10 can fly with one engine, one half of the tail, one elevator, and half of a wing missing.
Here's the part you've all been waiting for: the A-10's massive gun. Yes, the GAU-8/A Avenger is bigger than a VW Beetle. Yes, it fires 3,900 rounds per minute (although it was originally designed to fire at either 2,100 or 4,200 rounds per minute as dictated by the pilot). Yes, it goes 'BRRRT' when it shoots. As mentioned previously, the A-10 was designed around its gun. Although the gun itself is mounted slightly to the port side of the aircraft, the gun actually fires centerline because the barrel firing location is on the starboard side at 9 o'clock. This is critical since the gun is powerful enough to affect the aircraft's orientation if it mounted off-center. In fact, the Avenger produces 44.5 kN of rearward thrust when it fires. In theory, the A-10 could stall itself by firing its gun. However, because its rate of fire is so high, pilots usually fire in 1-2 second bursts. Its ammunition is also very special. Made of depleted uranium which is nearly twice as dense as lead and nearly three times as dense as iron, the A-10s 30x173mm rounds are designed to punch through enemy armor like a hot knife through butter. Depleted uranium also sharpens as it penetrates armor whereas tungsten, which is slightly denser, tends to dull on impact. As an added benefit, depleted uranium is cheap and readily available as a byproduct of uranium enrichment. The A-10 can carry up to 1,350 30mm rounds, the casings of which are cycled back into the ammunition drum to prevent them from striking the aircraft or getting sucked into the engines.
When it comes to design, it doesn't get much simpler than the A-10. Designed to operate from forward bases with little to no logistical or maintenance support, many of the A-10s components are interchangeable between its port and starboard side, including the engines, main landing gear, and vertical stabilizers. The wing design, sturdy landing gear, and low-pressure tires allow for short takeoffs and landings from even the most rudimentary forward landing strips. Similarly, the high engine placement helps to keep foreign object debris from entering them while operating from semi-prepared runways. The skin of the aircraft is not load-bearing and can be replaced easily in the field. Additionally, whereas most military aircraft require external power sources from ground crews in order to start their engines, the A-10 is equipped with an auxiliary power unit. This allows it to start itself and, again, operate from forward airfields with little to no support. In all, the A-10 is extremely cheap to fly, costing just ,944 per hour of operation. For comparison, the F-16 costs ,278 while the F-35 costs a whopping ,455.
The A-10 is a Cold War aircraft designed to cut through lines of Soviet tanks. Instead, it found renewed purpose in the War on Terror. Its effectiveness on the battlefield made it a favorite of both its pilots and the ground troops that it supported. When Congress threatened to put it on the chopping block, A-10 fans quickly took to the internet to voice their support for the 'Hog'. Today, just about everyone knows about the A-10. At the very least, they know the sound it makes—'BRRRT'.