Republic P-47G Thunderbolt
The P-47G was produced under license by Curtiss, at a factory in Buffalo that had previously produced the P-40. 354 P-47Gs were constructed, but production quality was never suitable for combat use, and the P-47Gs were instead used as training aircraft. This was still a valuable role, freeing the equivalent number of Republic produced aircraft for combat, but not what had been hoped for. The P-47G was produced in five blocks, each of which was virtually identical to an existing Republic model.
Two of the P-47G-15-CUs were converted into two-seat trainer aircraft, by adding a second cockpit in front of the original one. These aircraft were known as DoubleBolts. A small number of aircraft were converted to this role in the field by adding a second cockpit behind the original one.
Republic P-47 Thunderbolt
The Republic P-47 Thunderbolt was arguably the most important Army Air Forces fighter during World War II. Produced in greater numbers than any other fighter, the P-47, affectionately known as the "Jug," underwent continual modification and improvement during the war as its role expanded to include not only bomber escort but also tactical strafing and bombing.
P-47 Thunderbolt just after take-off from a XIX TAC airfield, during WW II.
|Today in WW II: 18 Jun 1940 General Charles de Gaulle broadcasts from London, calling on all French people to continue the fight against Nazi Germany. More &darr|
|18 Jun 1940 Winston Churchill speaks to Parliament, concluding, ". if the British Empire and its Commonwealth last for a thousand years, men will still say, 'This was their finest hour'".|
18 Jun 1941 Nazi Germany and Turkey sign treaty of friendship.
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Production model #1 flew in spring 1942 and #10,000 flew in fall 1944. The plane, produced by Republic Aviation, cost an average of $80,000 (compared to $50,000 for the smaller P-51). The 1945 version P-47M, burning 115/145 grade gasoline, had a maximum speed of 460 mph, a ceiling of 40,000 feet, and (with auxiliary drop tanks) a combat range of 2,000 miles. Escorting the B-17 and the B-29, its 8 50-caliber machine guns could rip apart Luftwaffe or Japanese fighters (which had only 90 octane gasoline). As a tactical weapon it was armed with five 500 pound bombs plus ten 5" rockets. At ten tons, the big Thunderbolt needed a long runway, and was less agile than the Luftwaffe's Focke-Wolf 190. But it was better than good enough, downing 3 German planes for every loss.
The main missions of the P-47 were tactical air support for ground combat, and (until the P-51 came on line), defending strategic bombers from Luftwaffe fighters. Although its loss rate was only 7 per 1,000 sorties, these tactical workhorses were sent out so often that half were shot down, chiefly by flak guns.
Infantrymen were ecstatic about the effectiveness of close air support:
Air strikes on the way we watch from a top window as P-47s dip in and out of clouds through suddenly erupting strings of Christmas-tree lights [flak], before one speck turns over and drops toward earth in the damnest sight of the Second World War, the dive-bomber attack, the speck snarling, screaming, dropping faster than a stone until it's clearly doomed to smash into the earth, then, past the limits of belief, an impossible flattening beyond houses and trees, an upward arch that makes the eyes hurt, and, as the speck hurtles away, WHOOM, the earth erupts five hundred feet up in swirling black smoke. More specks snarl, dive, scream, two squadrons, eight of them, leaving congealing, combining, whirling pillars of black smoke, lifting trees, houses, vehicles, and, we devoutly hope, bits of Germans. We yell and pound each other's backs. Gods from the clouds this is how you do it! You don't attack painfully across frozen plains, you simply drop in on the enemy and blow them out of existence. 
P-47B / P-47C
The XP-47B gave the USAAF (the "Air Corps" became the "Air Force" in June 1941) cause for both optimism and apprehension. Aircraft performance and firepower appeared to be everything asked for, but the XP-47B was something very new, and as a result it had it share of teething problems.
Its sheer size and power made it a handful. The XP-47B was also an "Earth lover", demanding a lot of runway to get into the air. This would not only be true for every other P-47 ever built, but also with Kartveli's later jet designs. There were problems with canopies that jammed, with the guns, with the fuel system, with the engine installation. At high altitudes, the ignition system arced, and the loads on the control surfaces became unacceptable, the ailerons locking up. The fabric-covered control surfaces also tended to rupture at high altitudes due to the air stored in them.
Republic addressed the problems, coming up with a sliding canopy that could be discarded in an emergency, a pressurized ignition system, and new all-metal control surfaces. While the engineers worked frantically to get their "dinosaur" to fly right, the USAAF had to think hard and ask themselves if they really wanted the P-47.
The answer was YES, and the Air Force ordered 171 "P-47Bs". A engineering prototype P-47B was delivered in December 1941, with a production prototype following in March 1942, and the first actual production model provided in May. Republic continued to tweak the design as P-47Bs were produced, and although the first P-47Bs had the sliding canopy, which also featured a better view for the pilot, plus a new General Electric (GE) turbo-supercharger regulator for the R-2800-21 engine, features such as all-metal control surfaces were not standard at first.
There was one minor change that would be unique to the P-47B. The radio mast behind the cockpit was slanted forward to maintain the aerial wire length even with the new sliding canopy.
The aircraft now had a name: "Thunderbolt". Pilots gave it a name of their own that would stick at least as well: "Jug". The derivation is said to be from the unstoppable cart of the Hindu gods, Juggernaut, but other sources indicate that the nickname was bestowed because of the milkjug shape of the fuselage. The plane's ability to take battle damage and still bring its pilot home would become legendary. (There is a story told within the fighter pilot community of one Thunderbolt pilot who, while trying to escape from a pair of experienced ME-109 pilots at low altitude, actually flew his Thunderbolt through a cathedral window in the brick wall of a bombed-out factory. He lost three feet of wingtip on each wing, his canopy was torn away and his propellor blades were bent, but the Jug just kept on flying. His opponents pulled up alongside him, supposedly took pictures of the flying wreck, and chivalrously escorted him back to the coast. The pilot landed at an emergency field in England and his P-47 never flew again, but it DID bring him home.)
Initial deliveries of the Thunderbolt to the USAAF were to the 56th Fighter Group (FG), which was also on Long Island. The 56th served as an operational evaluation unit for the new fighter.
Teething problems continued. A Republic test pilot was killed in an early production P-47B when it went out of control in a dive, and there were many crackups with other early P-47Bs, including crashes that occurred when the tail assembly fell off! The all-metal control surfaces and other changes corrected these problems, but the original XP-47B was lost in August 1942 when it caught in fire in flight, forcing the pilot to bail out.
On the balance, though, with experience the USAAF decided that the P-47 was worthwhile, and quickly followed the initial order for P-47Bs for 602 more examples of a refined type, the "P-47C", with the first of the variant delivered in September 1942.
The initial P-47Cs were very similar to the P-47B, but had strengthened all-metal control surfaces, an upgraded GE turbo-supercharger regulator, and a short vertical radio mast.
After the initial manufacture of a block of 57 P-47Cs, production moved to the "P-47C-1", which had a 200 millimeter (8 inch) fuselage extension forward of the cockpit. This corrected center of gravity problems, and made the engine easier to work on. There were a number of other minor changes, such as revised exhausts for the oil coolers, and fixes to brakes, undercarriage, and electrical system.
55 P-47C-1s were built, to be followed by 128 "P-47C-2s", which were identical except for a belly attachment point for either a 225 kilogram (500 lb) bomb or, more generally, a 758 liter (200 US gallon) drop tank.
The main production P-47C subvariant was the "P-47C-5", featuring a new whip antenna and a new R-2800-59 engine with water-methanol injection and a war emergency power rating of 2,300 horsepower (1700 kW).
The P-47B not only led to the P-47C but to a few other "one off" variants. A single reconnaissance variant designated "RP-47B" was built. The 171st and last P-47B was also used as a test platform under the designation "XP-47E", and was used to evaluate the R-2800-59 engine mentioned above, a pressurized cockpit, and eventually a new Hamilton Standard propeller.
Another P-47B was later fitted with new "laminar flow" wings in a search for higher performance and redesignated "XP-47F", but nothing came of this experiment.
Post-World War II development of conventionally armed attack aircraft in the United States had stagnated.  Design efforts for tactical aircraft focused on the delivery of nuclear weapons using high-speed designs like the F-101 Voodoo and F-105 Thunderchief.  Designs concentrating on conventional weapons had been largely ignored, leaving their entry into the Vietnam War led by the Korean War-era Douglas A-1 Skyraider. While a capable aircraft for its era, with a relatively large payload and long loiter time, the propeller-driven design was also relatively slow and vulnerable to ground fire. The U.S. Air Force and Navy lost 266 A-1s in action in Vietnam, largely from small arms fire.  The A-1 Skyraider also had poor firepower. 
The lack of modern conventional attack capability prompted calls for a specialized attack aircraft.   On 7 June 1961, Secretary of Defense McNamara ordered the USAF to develop two tactical aircraft, one for the long-range strike and interdictor role, and the other focusing on the fighter-bomber mission. The former became the Tactical Fighter Experimental, or TFX, which emerged as the F-111, while the second was filled by a version of the U.S. Navy's F-4 Phantom II. While the Phantom went on to be one of the most successful fighter designs of the 1960s and proved to be a capable fighter-bomber, its lack of loiter time was a major problem, and to a lesser extent, its poor low-speed performance. It was also expensive to buy and operate, with a flyaway cost of $2 million in FY1965 ($16.4 million today), and operational costs over $900 per hour ($7,000 per hour today). 
After a broad review of its tactical force structure, the U.S. Air Force decided to adopt a low-cost aircraft to supplement the F-4 and F-111. It first focused on the Northrop F-5, which had air-to-air capability.  A 1965 cost-effectiveness study shifted the focus from the F-5 to the less expensive LTV A-7D, and a contract was awarded. However, this aircraft doubled in cost with demands for an upgraded engine and new avionics. 
Helicopter competition Edit
During this period, the United States Army had been introducing the UH-1 Iroquois into service. First used in its intended role as a transport, it was soon modified in the field to carry more machine guns in what became known as the helicopter gunship role. This proved effective against the lightly armed enemy, and new gun and rocket pods were added. Soon the AH-1 Cobra was introduced. This was an attack helicopter armed with long-range BGM-71 TOW missiles able to destroy tanks from outside the range of defensive fire. The helicopter was effective, and prompted the U.S. military to change its defensive strategy in Europe by blunting any Warsaw Pact advance with anti-tank helicopters instead of the tactical nuclear weapons that had been the basis for NATO's battle plans since the 1950s. 
The Cobra was a quickly made helicopter based on the UH-1 Iroquois and, in the late 1960s, the U.S. Army was also designing the Lockheed AH-56 Cheyenne, a much more capable attack aircraft with greater speed. These developments worried the USAF, which saw the anti-tank helicopter overtaking its nuclear-armed tactical aircraft as the primary anti-armor force in Europe. A 1966 Air Force study of existing close air support (CAS) capabilities revealed gaps in the escort and fire suppression roles, which the Cheyenne could fill. The study concluded that the service should acquire a simple, inexpensive, dedicated CAS aircraft at least as capable as the A-1, and that it should develop doctrine, tactics, and procedures for such aircraft to accomplish the missions for which the attack helicopters were provided. 
A-X program Edit
On 8 September 1966, General John P. McConnell, Chief of Staff of the USAF, ordered that a specialized CAS aircraft be designed, developed, and obtained. On 22 December, a Requirements Action Directive was issued for the A-X CAS airplane,  and the Attack Experimental (A-X) program office was formed.  On 6 March 1967, the Air Force released a request for information to 21 defense contractors for the A-X. The objective was to create a design study for a low-cost attack aircraft.  In 1969, the Secretary of the Air Force asked Pierre Sprey to write the detailed specifications for the proposed A-X project Sprey's initial involvement was kept secret due to his earlier controversial involvement in the F-X project.  Sprey's discussions with Skyraider pilots operating in Vietnam and analysis of aircraft used in the role indicated the ideal aircraft should have long loiter time, low-speed maneuverability, massive cannon firepower, and extreme survivability  possessing the best elements of the Ilyushin Il-2, Henschel Hs 129, and Skyraider. The specifications also demanded that each aircraft cost less than $3 million (equivalent to $21.2 million today).  Sprey required that the biography of World War II Luftwaffe attack pilot Hans-Ulrich Rudel be read by people on the A-X program. 
In May 1970, the USAF issued a modified, more detailed request for proposals for the aircraft. The threat of Soviet armored forces and all-weather attack operations had become more serious. The requirements now included that the aircraft would be designed specifically for the 30 mm rotary cannon. The RFP also specified a maximum speed of 460 mph (400 kn 740 km/h), takeoff distance of 4,000 feet (1,200 m), external load of 16,000 pounds (7,300 kg), 285-mile (460 km) mission radius, and a unit cost of US$1.4 million ($9.3 million today).  The A-X would be the first USAF aircraft designed exclusively for close air support.  During this time, a separate RFP was released for A-X's 30 mm cannon with requirements for a high rate of fire (4,000 round per minute) and a high muzzle velocity.  Six companies submitted aircraft proposals, with Northrop and Fairchild Republic selected to build prototypes: the YA-9A and YA-10A, respectively. General Electric and Philco-Ford were selected to build and test GAU-8 cannon prototypes. 
Two YA-10 prototypes were built in the Republic factory in Farmingdale, New York, and first flown on 10 May 1972 by pilot Howard "Sam" Nelson. Production A-10s were built by Fairchild in Hagerstown, Maryland. After trials and a fly-off against the YA-9, on 18 January 1973, the USAF announced the YA-10's selection for production.  General Electric was selected to build the GAU-8 cannon in June 1973.  The YA-10 had an additional fly-off in 1974 against the Ling-Temco-Vought A-7D Corsair II, the principal USAF attack aircraft at the time, to prove the need for a new attack aircraft. The first production A-10 flew in October 1975, and deliveries commenced in March 1976. 
One experimental two-seat A-10 Night Adverse Weather (N/AW) version was built by converting an A-10A.  The N/AW 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 system officer responsible for electronic countermeasures (ECM), navigation and target acquisition. The N/AW version did not interest the USAF or export customers. The two-seat trainer version was ordered by the Air Force in 1981, but funding was canceled by U.S. Congress and the jet was not produced.  The only two-seat A-10 built now resides at Edwards Air Force Base's Flight Test Center Museum. 
On 10 February 1976, Deputy Secretary of Defense Bill Clements authorized full-rate production, with the first A-10 being accepted by the Air Force Tactical Air Command on 30 March 1976. Production continued and reached a peak rate of 13 aircraft per month. By 1984, 715 airplanes, including two prototypes and six development aircraft, had been delivered.  
When A-10 full-rate production was first authorized the aircraft's planned service life was 6,000 hours. A small reinforcement to the design was quickly adopted when the A-10 failed initial fatigue testing at 80% of testing with the fix, the A-10 passed the fatigue tests. 8,000-flight-hour service lives were becoming common at the time, so fatigue testing of the A-10 continued with a new 8,000-hour target. This new target quickly discovered serious cracks at Wing Station 23 (WS23) where the outboard portions of the wings are joined to the fuselage. The first production change was to add cold working at WS23 to address this problem. Soon after, the Air Force determined that the real-world A-10 fleet fatigue was more harsh than estimated, forcing them to change their fatigue testing and introduce "spectrum 3" equivalent flight-hour testing. 
Spectrum 3 fatigue testing started in 1979. This round of testing quickly determined that more drastic reinforcement would be needed. The second change in production, starting with aircraft No. 442, was to increase the thickness of the lower skin on the outer wing panels. A tech order was issued to retrofit the "thick skin" to the whole fleet, but the tech order was rescinded after roughly 242 planes, leaving about 200 planes with the original "thin skin". Starting with aircraft No. 530, cold working at WS0 was performed, and this retrofit was performed on earlier aircraft. A fourth, even more drastic change was initiated with aircraft No. 582, again to address the problems discovered with spectrum 3 testing. This change increased the thickness of the lower skin on the center wing panel, but it required modifications to the lower spar caps to accommodate the thicker skin. The Air Force determined that it was not economically feasible to retrofit earlier planes with this modification. 
The A-10 has received many upgrades since entering service. In 1978, the A-10 received the Pave Penny laser receiver pod, which receives reflected laser radiation from laser designators to allow the aircraft to deliver laser guided munitions. The Pave Penny pod is carried on a pylon mounted below the right side of the cockpit and has a clear view of the ground.   In 1980, the A-10 began receiving an inertial navigation system. 
In the early 1990s, the A-10 began to receive the Low-Altitude Safety and Targeting Enhancement (LASTE) upgrade, which provided computerized weapon-aiming equipment, an autopilot, and a ground-collision warning system. In 1999, aircraft began receiving Global Positioning System navigation systems and a multi-function display.  The LASTE system was upgraded with an Integrated Flight & Fire Control Computer (IFFCC). 
Proposed further upgrades included integrated combat search and rescue locator systems and improved early warning and anti-jam self-protection systems, and the Air Force recognized that the A-10's engine power was sub-optimal and had been planning to replace them with more powerful engines since at least 2001 at an estimated cost of $2 billion. 
HOG UP and Wing Replacement Program Edit
In 1987, Grumman Aerospace took over support for the A-10 program. In 1993, Grumman updated the damage tolerance assessment and Force Structural Maintenance Plan and Damage Threat Assessment. Over the next few years, problems with wing structure fatigue, first noticed in production years earlier, began to come to the fore. The process of implementing the maintenance plan was greatly delayed by the base realignment and closure commission (BRAC), which led to 80% of the original workforce being let go. 
During inspections in 1995 and 1996, cracks at the WS23 location were found on many aircraft, most of them in line with updated predictions from 1993. However, two of these were classified as "near-critical" size, well beyond predictions. In August 1998, Grumman produced a new plan to address these issues and increase life span to 16,000 hours. This resulted in the "HOG UP" program, which commenced in 1999. Over time, additional aspects were added to HOG UP, including new fuel bladders, changes to the flight control system, and inspections of the engine nacelles. In 2001, the cracks were reclassified as "critical", which meant they were considered repairs and not upgrades, which allowed bypassing normal acquisition channels for more rapid implementation. 
An independent review of the HOG UP program at this point concluded that the data on which the wing upgrade relied could no longer be trusted. This independent review was presented in September 2003. Shortly thereafter, fatigue testing on a test wing failed prematurely and also mounting problems with wings failing in-service inspections at an increasing rate became apparent. The Air Force estimated that they would run out of wings by 2011. Of the plans explored, replacing the wings with new ones was the least expensive, with an initial cost of $741 million, and a total cost of $1.72 billion over the life of the program. 
In 2005, a business case was developed with three options to extend the life of the fleet. The first two options involved expanding the service life extension program (SLEP) at a cost of $4.6 billion and $3.16 billion, respectively. The third option, worth $1.72 billion, was to build 242 new wings and avoid the cost of expanding the SLEP. In 2006, option 3 was chosen and Boeing won the contract.  The base contract is for 117 wings with options for 125 additional wings.  In 2013, the Air Force exercised a portion of the option to add 56 wings, putting 173 wings on order with options remaining for 69 additional wings.   In November 2011, two A-10s flew with the new wings fitted. The new wings improved mission readiness, decreased maintenance costs, and allowed the A-10 to be operated up to 2035 if necessary.  The re-winging effort was organized under the Thick-skin Urgent Spares Kitting (TUSK) Program. 
In 2014, as part of plans to retire the A-10, the USAF considered halting the wing replacement program to save an additional $500 million   however, by May 2015 the re-winging program was too far into the contract to be financially efficient to cancel.  Boeing stated in February 2016 that the A-10 fleet with the new TUSK wings could operate to 2040. 
In 2005, the entire fleet of 356 A-10 and OA-10 aircraft began receiving the Precision Engagement upgrades including an improved fire control system (FCS), electronic countermeasures (ECM), and smart bomb targeting. The aircraft receiving this upgrade were redesignated A-10C.  The Government Accounting Office in 2007 estimated the cost of upgrading, refurbishing, and service life extension plans for the A-10 force to total $2.25 billion through 2013.   In July 2010, the USAF issued Raytheon a contract to integrate a Helmet Mounted Integrated Targeting (HMIT) system into the A-10C.   The Air Force Material Command's Ogden Air Logistics Center at Hill AFB, Utah completed work on its 100th A-10 precision engagement upgrade in January 2008.  The final aircraft was upgraded to A-10C configuration in June 2011.  The aircraft also received all-weather combat capability,  and a Hand-on-Throttle-and-Stick configuration mixing the F-16's flight stick with the F-15's throttle. Other changes included two multifunction displays, a modern communications suite including a Link-16 radio and SATCOM.   The LASTE system was replaced with the integrated flight and fire control computer (IFFCC) included in the PE upgrade. 
Throughout its life, the platform's software has been upgraded several times, and although these upgrades were due to be stopped as part of plans to retire the A-10 in February 2014, Secretary of the Air Force Deborah Lee James ordered that the latest upgrade, designated Suite 8, continue in response to Congressional pressure. Suite 8 software includes IFF Mode 5, which modernizes the ability to identify the A-10 to friendly units.  Additionally, the Pave Penny pods and pylons are being removed as their receive-only capability has been replaced by the AN/AAQ-28(V)4 LITENING AT targeting pods or Sniper XR targeting pod, which both have laser designators and laser rangefinders. 
In 2012, Air Combat Command requested the testing of a 600-US-gallon (2,300 l 500 imp gal) external fuel tank which would extend the A-10's loitering time by 45–60 minutes flight testing of such a tank had been conducted in 1997 but did not involve combat evaluation. Over 30 flight tests were conducted by the 40th Flight Test Squadron to gather data on the aircraft's handling characteristics and performance across different load configurations. It was reported that the tank slightly reduced stability in the yaw axis, but there was no decrease in aircraft tracking performance. 
The A-10 has a cantilever low-wing monoplane wing with a wide chord.  The aircraft 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-foot (300 m) ceilings with 1.5-mile (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.  Its simple design enables maintenance at forward bases with limited facilities.   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. [Note 1] 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 retract forward if hydraulic power is lost, a combination of gravity and aerodynamic drag can lower and lock the gear in place. 
The A-10 is battle-hardened to an exceptional degree, 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 backup 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 be able to fly with one engine, half of the tail, one elevator, and half of a wing missing. 
The cockpit and parts of the flight-control systems 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 varying 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 six 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 demonstrated 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 one of her engines 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 intended to fly from forward air bases and semi-prepared runways where foreign object damage to an aircraft's engines is normally a high risk. The unusual location of the General Electric TF34-GE-100 turbofan engines decreases ingestion risk and also 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 contributes to 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' exhaust nozzles are angled nine degrees below horizontal to cancel out the nose-down pitching moment that would otherwise be generated from being mounted above the aircraft's center of gravity and avoid the need to trim the control surfaces to prevent pitching. 
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.   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.  
Since the A-10 operates very close to enemy positions, where it is an easy target for man-portable air-defense system (MANPADS), surface-to-air missiles (SAMs), and enemy aircraft, it carries both flares and chaff cartridges. 
Although the A-10 can carry a considerable amount of munitions, its primary built-in weapon is the 30×173 mm GAU-8/A Avenger autocannon. One of the most powerful aircraft cannons ever flown, it fires large depleted uranium armor-piercing shells. The GAU-8 is a hydraulically driven seven-barrel rotary cannon designed specifically for the anti-tank role with a high rate of fire. The cannon's original design could be switched by the pilot to 2,100 or 4,200 rounds per minute  this was later changed to a fixed rate of 3,900 rounds per minute.  The cannon takes about half a second to reach top speed, so 50 rounds are fired during the first second, 65 or 70 rounds per second thereafter. The gun is accurate enough to place 80 percent of its shots within a 40-foot (12.4 m) diameter circle from 4,000 feet (1,220 m) while in flight.  The GAU-8 is optimized for a slant range of 4,000 feet (1,220 m) with the A-10 in a 30-degree dive. 
The fuselage of the aircraft is built around the cannon. The GAU-8/A is mounted slightly to the port side the barrel in the firing location is on the starboard side at the 9 o'clock position so it is aligned with the aircraft's centerline. The gun's 5-foot, 11.5-inch (1.816 m) ammunition drum can hold up to 1,350 rounds of 30 mm ammunition,  but generally holds 1,174 rounds.  To protect the GAU-8/A rounds from enemy fire, armor plates of differing thicknesses between the aircraft skin and the drum are designed to detonate incoming shells.  
The AGM-65 Maverick air-to-surface missile is a commonly used munition for the A-10, targeted via electro-optical (TV-guided) or infrared. The Maverick allows target engagement at much greater ranges than the cannon, and thus less risk from anti-aircraft systems. During Desert Storm, in the absence of dedicated forward-looking infrared (FLIR) cameras for night vision, the Maverick's infrared camera was used for night missions as a "poor man's FLIR".  Other weapons include cluster bombs and Hydra rocket pods.  The A-10 is equipped to carry GPS and laser-guided bombs, such as the GBU-39 Small Diameter Bomb, Paveway series bombs, JDAM, WCMD and glide bomb AGM-154 Joint Standoff Weapon.  A-10s usually fly with an ALQ-131 ECM pod under one wing and two AIM-9 Sidewinder air-to-air missiles under the other wing for self-defense. 
The A-10 Precision Engagement Modification Program from 2006 to 2010 updated all A-10 and OA-10 aircraft in the fleet to the A-10C standard with a new flight computer, new glass cockpit displays and controls, two new 5.5-inch (140 mm) color displays with moving map function, and an integrated digital stores management system.    
Since then, the A-10 Common Fleet Initiative has led to further improvements: a new wing design, a new data link, the ability to employ smart weapons such as the Joint Direct Attack Munition (JDAM) and Wind Corrected Munitions Dispenser, as well as the newer GBU-39 Small Diameter Bomb, and the ability to carry an integrated targeting pod such as the Northrop Grumman Litening or the Lockheed Martin Sniper Advanced Targeting Pod (ATP). Also included is the Remotely Operated Video Enhanced Receiver (ROVER) to provide sensor data to personnel on the ground.  The A-10C has a Missile Warning System (MWS), which alerts the pilot to whenever there is a missile launch, friendly or non-friendly. The A-10C can also carry a ALQ-184 ECM Pod, which works with the MWS to detect a missile launch, figure out what kind of vehicle is launching the missile or flak (i.e.: SAM, aircraft, flak, MANPAD, etc.) and then jams it with confidential emitting, and selects a countermeasure program that the pilot has pre-set, that when turned on, will automatically dispense flare and chaff at pre-set intervals and amounts. 
Colors and markings Edit
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 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. 
Entering service Edit
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 Air Force Base, South Carolina, in October 1977.  Deployments of A-10As followed at bases both at home and abroad, including England AFB, Louisiana Eielson AFB, Alaska Osan Air Base, South 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 Air Base, and RAF Ahlhorn. 
A-10s were initially an unwelcome addition to many in the Air Force. Most pilots switching to the A-10 did not want to because fighter pilots traditionally favored speed and appearance.  In 1987, many A-10s were shifted to the forward air control (FAC) role and redesignated OA-10.  In the FAC role, the OA-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 are physically unchanged and remain fully combat capable despite the redesignation. 
A-10s of the 23rd TFW were deployed to Bridgetown, Barbados during Operation Urgent Fury, the American Invasion of Grenada. They provided air cover for the U.S. Marine Corps landings on the island of Carriacou in late October 1983, but did not fire weapons as Marines met no resistance.   
Gulf War and Balkans Edit
The A-10 was used in combat for the first time during the Gulf War in 1991, destroying more than 900 Iraqi tanks, 2,000 other military vehicles and 1,200 artillery pieces.  A-10s also shot down two Iraqi helicopters with the GAU-8 cannon. The first of these was shot down by Captain Robert Swain over Kuwait on 6 February 1991 for the A-10's first air-to-air victory.   Four A-10s were shot down during the war by surface-to-air missiles. Another two battle-damaged A-10s and OA-10As returned to base and were written off. Some sustained additional damage in crash landings.   The A-10 had a mission capable rate of 95.7 percent, flew 8,100 sorties, and launched 90 percent of the AGM-65 Maverick missiles fired in the conflict.  Shortly after the Gulf War, the Air Force abandoned the idea of replacing the A-10 with a close air support version of the F-16. 
U.S. Air Force A-10 aircraft fired approximately 10,000 30 mm rounds in Bosnia and Herzegovina in 1994–95. Following the seizure of some heavy weapons by Bosnian Serbs from a warehouse in Ilidža, a series of sorties were launched to locate and destroy the captured equipment. On 5 August 1994, two A-10s located and strafed an anti-tank vehicle. Afterward, the Serbs agreed to return the remaining heavy weapons.  In August 1995, NATO launched an offensive called Operation Deliberate Force. A-10s flew close air support missions, attacking Bosnian Serb artillery and positions. In late September, A-10s began flying patrols again. 
A-10s returned to the Balkan region as part of Operation Allied Force in Kosovo beginning in March 1999.  In March 1999, A-10s escorted and supported search and rescue helicopters in finding a downed F-117 pilot.  The A-10s were deployed to support search and rescue missions, but over time the Warthogs began to receive more ground attack missions. The A-10's first successful attack in Operation Allied Force happened on 6 April 1999 A-10s remained in action until combat ended in late June 1999. 
Afghanistan, Iraq, Libya, and recent deployments Edit
During the 2001 invasion of Afghanistan, A-10s did not take part in the initial stages. For the campaign against Taliban and Al Qaeda, A-10 squadrons were deployed to Pakistan and Bagram Air Base, Afghanistan, beginning in March 2002. These A-10s participated in Operation Anaconda. Afterward, A-10s remained in-country, fighting Taliban and Al Qaeda remnants. 
Operation Iraqi Freedom began on 20 March 2003. Sixty OA-10/A-10 aircraft took part in early combat there.  United States Air Forces Central Command issued Operation Iraqi Freedom: By the Numbers, a declassified report about the aerial campaign in the conflict on 30 April 2003. During that initial invasion of Iraq, A-10s had a mission capable rate of 85 percent in the war and fired 311,597 rounds of 30 mm ammunition. A single A-10 was shot down near Baghdad International Airport by Iraqi fire late in the campaign. The A-10 also flew 32 missions in which the aircraft dropped propaganda leaflets over Iraq. 
In September 2007, the A-10C with the Precision Engagement Upgrade reached initial operating capability.  The A-10C first deployed to Iraq in 2007 with the 104th Fighter Squadron of the Maryland Air National Guard.  The A-10C's digital avionics and communications systems have greatly reduced the time to acquire a close air support target and attack it. 
A-10s flew 32 percent of combat sorties in Operation Iraqi Freedom and Operation Enduring Freedom. The sorties ranged from 27,800 to 34,500 annually between 2009 and 2012. In the first half of 2013, they flew 11,189 sorties in Afghanistan.  From the beginning of 2006 to October 2013, A-10s conducted 19 percent of CAS missions in Iraq and Afghanistan, more than the F-15E Strike Eagle and B-1B Lancer, but less than the 33 percent flown by F-16s. 
In March 2011, six A-10s were deployed as part of Operation Odyssey Dawn, the coalition intervention in Libya. They participated in attacks on Libyan ground forces there.  
The USAF 122nd Fighter Wing revealed it would deploy to the Middle East in October 2014 with 12 of the unit's 21 A-10 aircraft. Although the deployment had been planned a year in advance in a support role, the timing coincided with the ongoing Operation Inherent Resolve against ISIL militants.    From mid-November, U.S. commanders began sending A-10s to hit IS targets in central and northwestern Iraq on an almost daily basis.   In about two months time, A-10s flew 11 percent of all USAF sorties since the start of operations in August 2014.  On 15 November 2015, two days after the ISIL attacks in Paris, A-10s and AC-130s destroyed a convoy of over 100 ISIL-operated oil tanker trucks in Syria. The attacks were part of an intensification of the U.S.-led intervention against ISIL called Operation Tidal Wave II (named after Operation Tidal Wave during World War II, a failed attempt to raid German oil fields) in an attempt to cut off oil smuggling as a source of funding for the group. 
On 19 January 2018, 12 A-10s from the 303d Expeditionary Fighter Squadron were deployed to Kandahar Airfield, Afghanistan, to provide close-air support, marking the first time in more than three years A-10s had been deployed to Afghanistan. 
The future of the platform remains the subject of debate. In 2007, the USAF expected the A-10 to remain in service until 2028 and possibly later,  when it would likely be replaced by the Lockheed Martin F-35 Lightning II.  However, 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 high 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. The prevalence of guided munitions allows more aircraft to perform the CAS mission and reduces the requirement for specialized aircraft since 2001 multirole aircraft and bombers have performed 80 percent of operational CAS missions. The Air Force also said that the A-10 was more vulnerable to advanced anti-aircraft defenses, but the Army replied that the A-10 had proved invaluable because of its versatile weapons loads, psychological impact, and limited 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  that year General Herbert J. Carlisle, the head of Air Combat Command, stated that a follow-on weapon system for the A-10 May need to be developed.  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.  In July 2015, Boeing held initial discussions on the prospects of selling retired or stored A-10s in near-flyaway condition to international customers.  However, the Air Force then said that it would not permit the aircraft to be sold. 
Plans to develop a replacement aircraft were announced by the US Air Combat Command in August 2015.   Early the following year, the Air Force began studying future CAS aircraft to succeed the A-10 in low-intensity "permissive conflicts" like counterterrorism and regional stability operations, admitting that the F-35 would be too expensive to operate in day-to-day roles. A wide range of platforms were under consideration, including everything from low-end AT-6 Wolverine and A-29 Super Tucano turboprops and the Textron AirLand Scorpion as more basic off-the-shelf options to more sophisticated clean-sheet attack aircraft or "AT-X" derivatives of the T-X next-generation trainer as entirely new attack platforms.   
In January 2016, the USAF 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.   In February 2016, the Air Force deferred the final retirement of the aircraft until 2022 after being replaced by F-35s on a squadron-by-squadron basis.   In October 2016, the Air Force Material Command brought the depot maintenance line back to full capacity in preparation for re-winging the fleet.  In June 2017, it was announced that the aircraft ". will now be kept in the air force’s inventory indefinitely."  
Other uses Edit
On 25 March 2010, an A-10 conducted the first flight of an aircraft with all engines powered by a biofuel blend. The flight, performed at Eglin Air Force Base, used a 1:1 blend of JP-8 and Camelina-based fuel.  On 28 June 2012, the A-10 became the first aircraft to fly using a new fuel blend derived from alcohol known as ATJ (Alcohol-to-Jet), the fuel is cellulosic-based and can be produced using wood, paper, grass, or any cellulose based material, which are fermented into alcohols before being hydro-processed into aviation fuel. ATJ is the third alternative fuel to be evaluated by the Air Force as a replacement for the petroleum-derived JP-8 fuel. Previous types were a synthetic paraffinic kerosene derived from coal and natural gas and a bio-mass fuel derived from plant-oils and animal fats known as Hydroprocessed Renewable Jet. 
Why America's P-47 "Razorback" Was Such a Good Fighter Plane
Key point: The P-47 would dish out punishment and take a fair amount of damage. But it did have engine problems.
Pilots nicknamed early-model P-47 Thunderbolts the “Razorback,” a reference to the chunky fighter plane’s angular canopy. However, the name was more generally appropriate—like a wild boar, the hulking single-engine “Jug” was tough and hard-charging, and its eight .50 caliber machine guns packed a hell of a punch.
This first appeared in January 2019 and is being reposted due to reader interest.
Lugging underwing fuel tanks, Thunderbolts based in Britain could accompany four-engine B-17 and B-24 bombers of the 8 th Air Force on dangerous raids deep over Nazi Germany—and still engage German fighters on roughly even terms, especially while diving.
However, starting mid-1944, the Allied fliers grew concerned about new Nazi turbojet-powered Me-262 fighters and rocket-powered Me-163s that could outrun the speediest Allied piston-engine aircraft like the Mustang or British Tempest by 100 miles per hour or more. V-1 “Buzz Bomb” cruise missiles bombarding London, though slower, also proved difficult for Allied fighters to intercept.
On its own initiative, Thunderbolt manufacturer Republic set aside four bubble-canopy P-47Ds from its production line in Farmingdale, New York and fit them with souped-up Pratt & Whitney R-2800-57 Double Wasp engine with a turbo-supercharger. Together, these could generate 2,800 horsepower.
At high altitude, the yellow-painted YP-47M prototypes could attain a climb rate of 3,500 feet per second and a maximum speed of 473 miles per hour in level flight—though some pilots reported achieving 490 to 500 mph when using Wartime Emergency Power. This made the P-47M arguably the fastest piston-engine fighter to see combat in the war—though still slower than the Me-262’s 540-miles per hour maximum speed.
Though Republic produced more radical XP-47H and J prototypes that could go even faster, the YP-47 could be easily put into production, so in September 1944 the Army Air Corps approved a limited run of 130 P-47M-1-RE aircraft. These were delivered in December 1944 and began to be received by their sole operator, the elite 56 th Fighter Group based at Boxted Airfield near Colchester, England on January 3.
The 56 th , better known as Zemke’s Wolfpack after its legendary first ace commander, was the only unit in the strategic-bombing-focused 8 th Air Force not to trade its Thunderbolts for P-51D Mustangs, a sleeker and more agile (though less robust) fighter. The Wolfpack’s three squadrons completed conversion to the P-47M by March, each with a unique camouflage scheme: dark black wing-tops for the 61 st , green/grey disruptive pattern for the 62 nd , and a striking blue/teal pattern for the 63 rd .
The 56 th also received new experimental T48 .50-caliber incendiary rounds designed to ignite kerosene jet fuel, which has a higher combustion temperature. The 500-grain rounds, manufactured by the Des Moines Ordnance Plant, were stuffed with 5.4 ounces of incendiary composite—twice the quantity in the standard M1 round.
However, the juiced-up engines of the P-47Ms were plagued by serious technical problems. After a Thunderbolt crash landed due to engine trouble, a crack ignition harness was discovered. Then, on February 26, a problem with the fuel carburetor diaphragm was identified, causing the P-47Ms to be grounded while a local company built new gaskets.
But these fixes didn’t bring an end to the P-47M’s woes. On an escort mission on April 4, six out of fourteen Thunderbolts had to abort mission with engine trouble. The breakdowns took a deadly turn between April 11 and 15 as three pilots were killed in engine-related accidents. The P-47Ms were grounded again on April 16 , and the Wolfpack pilots reluctantly began training on Mustangs.
Meanwhile, technicians poured over the trouble R2800-57’s engines—and discovered rust in the pistons. The super Double Wasp engines had been improperly sealed for transport across the Atlantic, allowing humid ocean air to corrode the pistons.
By March 25, replacement engines had been procured and the 56 th was back to operational status. Despite the growing paucity of Luftwaffe targets, the P-47M went on to distinguish itself performing exactly the kind of mission it had been designed for—shooting down Nazi jets.
In fact, the P-47M’s first two jet kills occurred prior to solving the corrosion problem. On March 14, three P-47s of the 62 nd fighter squadron swooped down upon two low-flying Arado 234B jet bombers. The twin-engine jet bombers were likely targeting the battered Ludendorff Bridge in Remagen over which the U.S. 1 st Army was pouring into Germany. The P-47Ms, roughly equaling the Arado’s in speed, shot down both.
Then on March 25, Wisconsinite Major George Bostwick, commander of the 63 rd Squadron, and wingman Edwin Crosthwait dispatched two Me-262s as they came in for a landing at Parchim airfield—a time at which jet fighters were notoriously vulnerable. Bostwick and his Thunderbolt “Ugly Duckling” (pictured together here) ended the war with eight air-to-air kills.
Though the Luftwaffe was increasingly crippled by a lack of fuel and trained pilots, Me-262’s still posed a deadly threat to U.S. bombers. Fifty-three Thunderbolts were escorting a raid targeting Regensburg on April 5 when a lone Me-262 came streaking in from 3 o’clock at over 500 miles per hour, zipped unscathed through a hail of defensive machine gun fire and blasted a B-17 out of the sky with its four powerful 30-millimeter cannons. The escorting Razorbacks tore after the speeding jet as it peeled away at 9 o’clock—including “Devastatin’ Deb,” piloted by Captain John C. Fahringer.
Stephen Chapis described the action in Allied Jet Killers of World War II:
“The P-47s jettisoned their tanks and headed down in pursuit. 1 st Lt. Phillip Kuhn fired first, before overshooting, after which Fahringer rolled in on the Me-262’s tail and let it have several bursts to no effect. However, the German pilot then made the fatal mistake of tightening his turn, which allowed Fahringer to close into lethal range. At 500 yards, he opened up again with this Thunderbolt’s eight .50-cal machine guns, and as the smoke began pouring from the jet Fahringer saw something go down the right side of his P-47. It was the pilot of the Me 262.”
On April 10, Lieutenants Walter Sharbo and Bill Wilkerson shot down two more Me-262s over Muritz lake while returning from a fighter sweep over Berlin. These were the last two aerial victories of the 56 th Fighter Group.
Three days later, after failing to encounter enemy fighters on an escort mission, the Wolfpack swooped down on Eggebek airfield, their chattering machine-guns expending 85,000 rounds and destroying ninety-five parked aircraft on the ground.
The new incendiary ammunition proved especially devastating. After the German surrender, an air force report enthused “…enemy aircraft burned after having been hit only two or three times. . . . One pilot destroyed 10 aircraft on a single mission by firing short bursts.” This may be referring to 2 nd Lt. Randall Murphy, whose gun camera recorded the destruction of ten aircraft during the Eggebek strike.
Zemke’s Wolfpack ended the war the top-scoring U.S. fighter group of the 8 th Air Force, with 665.5 recognized aerial kills—or one thousand aircraft destroyed, including those strafed on the ground. The P-47Ms, which served after the Luftwaffe was largely defeated, claimed only fifteen of those victories—though that included at least seven jet aircraft. Twelve P-47Ms were lost in accidents, and two shot down by ground fire, but not one fell in air-to-air combat.
In recognition of the Wolfpack’s achievements, a P-47M was displayed under the Eiffel Tower for a victory celebration that July. Meanwhile, Republic developed the P-47M into to the ultimate P-47N model, 1,800 of which were built. Though slightly slower than the P-47M due to greater weight, the N was modified to fly up to 1,800 miles on internal fuel thanks to additional tanks incorporated in the wings—a useful quality for the long-range missions it flew in the final months of the War in the Pacific.
Sébastien Roblin holds a master’s degree in conflict resolution from Georgetown University and served as a university instructor for the Peace Corps in China. He has also worked in education, editing, and refugee resettlement in France and the United States. He currently writes on security and military history for War Is Boring. This first appeared in January 2019 and is being reposted due to reader interest.
Republic P-47G Thunderbolt - History
Constructed as a P-47D-40-RA by Republic at Evansville, Indiana, USA.
Taken on Strength/Charge with the United States Army Air Force with s/n 44-90368.
Transferred to 2678th Fighter Pilot Training School.
Transferred to 4200th Base Unit (Fairfield ATSC), Chicago Municipal Airport, IL.
Transferred to USAAF Ferry Command.
Transferred to 2498th Base Unit.
Transferred to 4112th Base Unit, Olmstead AFB, PA.
Transferred to 4121st Base Unit, San Antonio Air Materiel Command, Kelly Field, San Antonio, TX.
Transferred to Central Air Command.
Struck off Strength/Charge from the United States Army Air Force.
Taken on Strength/Charge with the Fuerza Aerea Venezolana with s/n 490368/6.
The delivery date is provided.
To Steve Schulke, Orlando, FL.
To Jean Salis Collection, La Ferte-Alais, France.
Stored unrestored at La Ferte-Alais.
To Charles A. Osborn, Louisville, KY.
From June 1991 to By 1998
To Blue Sky Aviation/Charles A. Osborn, Louisville KY Sellersburg, IN with new c/r N4747P.
Certificate of airworthiness for NX4747P (P47D-40-RA, 44-90368) issued.
First post-restoration Flight.
Photographer: Glenn Chatfield
Notes: At Oshkosh, WI
Photographer: Glenn Chatfield
Notes: At Oshkosh, WI
Photographer: Glenn Chatfield
Photographer: Ken Videan
Notes: At EAA Oshkosh.
Markings Applied: TARHEEL HAL, 44-33240
Photographer: Mike Henniger
Notes: Photographed at the Dayton International Air and Trade Show at Dayton, Ohio.
Photographer: Mike Henniger
Notes: Photographed at the Wings of Eagles Airshow at Batavia, New York.
To Air SRV Inc/Lone Star Flight Museum, Galveston, TX keeping c/r N4747P.
Based at Lone Star Flight Museum, Scholes Field, Galveston, TX.
View the Location Dossier
Markings Applied: Tarheel Hal, IA N, 433240
To Texas Aviation Hall of Fame, Galveston, TX keeping c/r N4747P.
Photographer: Jeff Hunt
Notes: Thunder Over Michigan Air Show
Certificate of airworthiness for NX4747P (P47D-40-RA, 44-90368) issued.
Photographer: Gustavo Bonilla
Notes: Lone Star Flight Museum in Galveston,
To Lone Star Flight Museum, Galveston, TX keeping c/r N4747P.
To Lone Star Flight Museum, Houston, TX keeping c/r N4747P.
From Unknown to October 2020
Based at Lone Star Flight Museum, Ellington Field, Houston, TX.
View the Location Dossier
|Variant ||Number built ||Serial number(s) ||Notes |
|XP-47 ||1 ||40-3051 ||Prototype cancelled during construction |
|XP-47A ||1 ||40-3052 ||Prototype cancelled during construction |
|Total XP-47, XP-47A ||2 || || |
|XP-47B ||1 ||40-3052 (serial number transferred from abortive XP-47A) ||Prototype R-2800-21 engine |
|Total XP-47B ||1 || || |
|P-47B-RE ||171 ||41-5895/6065 ||R-2800-21 engine modified metal-covered ailerons trim tabs sliding canopy windshield defroster 41-5938 converted to XP-47F with larger laminar flow wing 41-6065 converted to XP-47E with pressurized cockpit and hinged canopy |
|Total P-47B ||171 || || |
|P-47C-RE ||58 ||41-6066/6123 ||R-2800-21 engine strengthened tail surfaces |
|P-47C-1-RE ||54 ||41-6124/6177 ||R-2800-21 engine eight-inch extension added to fuselage forward of cockpit |
|P-47C-2-RE ||128 ||41-6178/6305 ||R-2800-21 engine belly shackle provided for bomb or fuel tank |
|P-47C-5-RE ||362 ||41-6306/6667 ||R-2800-21 engine new radio, instruments, and antenna cockpit heater |
|Total P-47C ||602 || || |
|P-47D-1-RE ||105 ||42-7853/7957 ||R-2800-21 engine nearly identical to P-47C-2-RE additional cowl flaps and pilot armor |
|P-47D-1-RA ||114 ||42-22250/22363 ||R-2800-21 engine the first variant of the P-47 built at Republic's new factory in Evansville, Indiana identical to P-47D-1-RE |
|P-47D-2-RE ||445 ||42-7958/8402 ||R-2800-21 engine turbocharger shroud removed |
|P-47D-2-RA ||200 ||42-22364/22563 ||R-2800-21 engine identical to P-47D-2-RE |
|P-47D-3-RA ||100 ||42-22564/22663 ||R-2800-21 engine minor upgrade to D-2-RA |
|P-47D-4-RA ||200 ||42-22664/22863 ||R-2800-21 engine Evansville-built P-47D-5-RE |
|P-47D-5-RE ||300 ||42-8403/8702 ||R-2800-21 engine used General Electric C-21 supercharger and had provision for water injection belly shackle for bomb or fuel tank reintroduced and was standard on all P-47s from then on 42-8702 fitted with bubble canopy and redesigned XP-47K |
|P-47D-6-RE ||350 ||42-74615/74964 ||R-2800-21 engine minor changes to electrical system |
|P-47D-10-RE ||250 ||42-74965/75214 ||New R-2800-63 engine and changes to water injection system |
|P-47D-11-RE ||400 ||42-75215/75614 ||R-2800-63 engine contained all features introduced between the D-5 and D-10 water injection linked to throttle lever |
|P-47D-11-RA ||250 ||42-22864/23113 ||R-2800-63 engine identical to P-47D-11-RE |
|P-47D-15-RE ||446 ||42-75615/75814, 42-76119/76364 ||R-2800-63 engine first model of P-47 with underwing pylons stronger wings |
|P-47D-15-RA ||157 ||42-23143/23299 ||R-2800-63 engine 42-23297 and 42-23298 converted to XP-47H with Chrysler IV-2220-11 inverted-vee engines identical to P-47D-15-RE |
|P-47D-16-RE ||254 ||42-75865/76118 ||R-2800-63 engine minor changes to fuel system |
|P-47D-16-RA ||29 ||42-23114/23142 ||R-2800-63 engine identical to P-47D-16-RE |
|P-47D-20-RE ||299 ||42-25274/25322, 42-76365/76614 ||New R-2800-59 engine modified underwing pylons 42-76614 fitted with increased fuel capacity and bubble canopy as XP-47L |
|P-47D-20-RA ||187 ||43-25254/25440 ||R-2800-59 engine identical to P-47D-20-RE |
|P-47D-21-RE ||216 ||42-25323/25538 ||R-2800-59 engine changes to water injection system |
|P-47D-21-RA ||224 ||43-25441/25664 ||Identical to P-47D-21-RE |
|P-47D-22-RE ||850 ||42-25539/26388 ||R-2800-59 engine Farmingdale factory switched to Hamilton Standard paddle-bladed propeller |
|P-47D-23-RA ||889 ||42-27389/28188, 43-25665/25753 ||R-2800-59 engine Evansville factory switched to Curtiss Electric paddle-bladed propeller |
|P-47D-25-RE ||385 ||42-26389/26773 ||R-2800-59 engine bubble canopy fuel capacity increased from 305 to 370 gallons |
|P-47D-26-RA ||250 ||42-28189/28438 ||R-2800-59 engine identical to P-47D-25-RE |
|P-47D-27-RE ||615 ||42-26774/27388 ||R-2800-59 engine improved water injection system |
|P-47D-28-RE ||750 ||44-19558/20307 ||R-2800-59 engine Farmingdale factory switched to Curtiss Electric paddle-bladed propeller radio compass added |
|P-47D-28-RA ||1,028 ||42-28439/29466 ||R-2800-59 engine Identical to P-47D-28-RE |
|P-47D-30-RE ||800 ||44-20308/21107 ||R-2800-59 engine Dive brakes added under wings |
|P-47D-30-RA ||1,800 ||44-32668/33867, 44-89684/90283 ||R-2800-59 engine Identical to P-47D-30-RE |
|P-47D-40-RA ||665 ||44-90284/90483, 45-49090/49554 ||R-2800-59 engine Dorsal fin added to vertical stabilizer |
|Total P-47D ||12,558 || || |
|P-47G-CU ||20 ||42-24920/24939 ||P-47Gs were built by Curtiss and used for stateside training the P-47G-CU was identical to the P-47C-RE |
|P-47G-1-CU ||40 ||42-24940/24979 ||Identical to P-47C-1-RE |
|P-47G-5-CU ||60 ||42-24980/25039 ||Identical to P-47D-1-RE |
|P-47G-10-CU ||80 ||42-25040/25119 ||Identical to P-47D-5-RE |
|P-47G-15-CU ||154 ||42-25120/25273 ||Identical to P-47D-10-RE two converted to TP-47G trainer variant |
|Total P-47G ||354 || || |
|XP-47J ||1 ||43-46952 ||Lightweight prototype newly-built airframe reduced armament |
|Total XP-47J ||1 || || |
|P-47M-1-RE ||130 ||44-21108/21237 ||High-speed variant using R-2800-57 engine designed to combat German jet and rocket-powered aircraft |
|Total P-47M ||130 || || |
|P-47N-1-RE ||550 ||44-87784/88333 ||Long-range variant designed for service in the Pacific Theater R-2800-57 engine larger wings with squared-off tips increased fuel capacity automation of some engine controls |
|P-47N-5-RE ||550 ||44-88334/88883 ||R-2800-57 engine "zero-length" stubs for 5-inch rockets autopilot |
|P-47N-15-RE ||200 ||44-88884/89083 ||R-2800-73 or -77 engine new bomb rack and gunsight autopilot not fitted to this model |
|P-47N-20-RE ||200 ||44-89084/89283 ||R-2800-73 or -77 engine backup fuel system added |
|P-47N-25-RE ||167 ||44-89284/89450 ||R-2800-73 or -77 engine strengthened wings and more automation of engine control systems |
|P-47N-20-RA ||149 ||45-49975/50123 ||R-2800-73 or -77 engine the final P-47Ns, and hence the final P-47s, were built by the Evansville factory |
|Total P-47N ||1,816 || || |
|Total, all types ||15,636 || || |
Republic P-47 Thunderbolt
The Republic P-47 Thunderbolt, also known as the 'Jug,' was the biggest, heaviest, and most expensive fighter aircraft in history to be powered by a single piston engine. It was one of the main United States Army Air Forces (USAAF) fighters of World War II, and also served with other Allied air forces. The P-47 was effective in air combat but proved especially adept at ground attack. It had eight .50-caliber machine guns, four per wing. When fully loaded the P-47 could weigh up to eight tons. A modern-day counterpart in that role, the A-10 Thunderbolt II, takes its name from the P-47.
This webpage was updated 25th November 2012
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Remembering the Republic P-47 Thunderbolt
True enthusiasts will be the first to admit that, had it not been for the events of World War Two, the sports car scene in the States would most certainly look much different. Americans sent to serve in England were introduced to a scene that included MG, Riley, and a number of other sporting makes but most will agree that the hottest machines operating in Europe in the early 1940s not only had wheels, but wings to take the fight to the enemy high above the skies of Europe. One of those brilliant aircraft was built by Republic Aviation in New York, affectionately dubbed “The Jug,” the aircraft was officially known as the P-47 Thunderbolt.
The P-47 wasn’t a clean sheet design as its more famous counterpart, the P-51 Mustang was, but was an evolution of sorts gaining its origins in a Seversky design which entered the US inventory in 1937 and was assigned the designation P-35. The P-35 ushered in a new era for the United States Army Air Corps when it entered service in 1937 at Selfridge, Michigan by being the first all metal single seat pursuit aircraft with an enclosed cockpit and fully retractable landing gear. Armament was light, as the P-35 carried just one .50 caliber machine gun and one .30 caliber machine gun, both located in the fuselage of the aircraft. The P-35 set the formula, so to speak, by being powered by a Pratt and Whitney R-1830 radial engine rated at 850HP and giving the P-35 a top speed of 280mph.
With the outbreak of hostilities in Europe in late 1939, the U.S. began producing new aircraft, initially based on demands outlined by allied customers, and eventually put into service with our own Air Corps upon U.S. entry into the war in December of 1941. By the spring of 1941, U.S. industry was ramping up in order to fill requests for allied nations. The aviation industry enjoyed rapid growth in the U.S. at this time and Seversky, now known as Republic, rolled out a new aircraft that was unlike any other competitor in the growing pursuit aircraft market.
The first test flight of a Republic XP-47B occurred on May 6, 1941 with the first production piece reaching the U.S. Army Air Force on March 18, 1942. On April 8, 1943 P-47Bs flew their first fighter sweep into Europe, setting the stage for the progression of one of the most famous fighters ever to take to the skies. Pilots were immediately in love with this massive fighter aircraft, as though it weighed in at 13,500 lbs, the Thunderbolt had near cat like agility operating at high altitudes. This was a great relief to American bomber crews of the Mighty Eighth Air Force who were tasked with flying long distance daylight raids into the heart of Germany, often with little or no fighter escort due to the lack of range of most fighter aircraft of the time. The P-47 was the first step to solving that problem as Jugs fitted with external fuel tanks were capable of flying with the bombers to most of the targets deep within Germany. The P-47C was introduced with a more powerful Pratt and Whitney radial and a provision for a droppable center line tank just to meet the escort role. With the extra fuel, Thunderbolts were able to make it all the way to Berlin with the bombers to hit the heart of the Axis movement.
In early 1943, Republic began producing the “D” model Thunderbolt. Early D models aircraft retained the “razorback” canopy treatment as breakthroughs were occurring daily in the aviation industry in the early 1940s and it wasn’t until mid production of the D model that the now famous bubble canopy appeared, eliminating the blind spot that all prior models had due to the razorback canopy design. D model Thunderbolts received many improvements over their earlier counterparts, with yet even more power being extracted by the thunderous Pratt and Whitney Double Wasp 18 cylinder engine, the R2800. Much of the power was to come from more efficient turbo-charging and the introduction of water injection to directly cool the mixture being burned in those massive cylinders. Now rated at over 2300+ horsepower, the Jug began to show that it had more up its sleeve than just escorting the “Heavies.”
With the exception of Alaska, the Thunderbolt flew in every theatre of the war. The Ninth Air Force flew Thunderbolts out of England and largely developed the aircraft for use in the ground attack role, taking out enemy ground targets and providing close air support to soldiers in need of a little help from above. One of the most successful units of the war was the 325th Fighter Group, who began flying P-47s out of Italy in January of 1944. The group flew Curtis P-40s while in North Africa and Sicily throughout 1943, transitioning to Jugs in late ’43 and flying their first missions from Italy in January of ’44. Wayne Lowery, a pilot with the 325th remarked “The Thunderbolt turned out to be a lovable beast, forgiving my many errors of omission as well as commission.” Lowery continues, “Performance wise, in a turn the Jug was nothing to shout about, but at high altitude it had the most amazing maneuverability of any airplane I have ever flown. She seemed to thrive on thin air. I can also say that I have never flown an aircraft before or since that could get rid of so much altitude in such a short time. It also had an inclination to reverse its controls in a high speed dive, especially in the thin air at higher altitudes.”
Bob Baseler was the commander of the 325th Fighter Group and flew P-40s, P-47s, and P-51s with the outfit. Baseler’s P-47D was known as “Big Stud” and had those words along with an Ace of Spades card painted on the engine nacelle. Baseler relates, “It was a fine weapon, could take lots of punishment and dish it out, too. It was dependable, no worrying about coolant leaks, easy to maintain, and just an all round good aircraft.”
The “D” model Thunderbolt may be the most popular Thunderbolt variant, however the “M” model was a true high performance hot rod special of this large and lethal bird of prey. The P-47M debuted in the UK in December of 1944 and was aimed at intercepting the V-1 flying bombs that Germany was launching against England at the time. While a “D” model Jug was no slouch with a max speed of 433mph, the limited edition “M” models screamed out to a bat out of hell top speed of 470mph. The P-47Ms were fitted with airbrakes in order to slow once it got with in range of its prey. “M” model Thunderbolts also enjoyed harassing Me262 and Ar234 jet aircraft that began to be seen more and more often in early 1945.
Republic P-47N Thunderbolt
Republic P-47D Thunderbolt
Republic P-47D Thunderbolt in flight
Republic P-47D Thunderbolt parked
Republic began production of the P-47N in December of 1944. The “N” was more directed at the Pacific theatre of operations, where long flights over the Pacific Ocean heeded a demand for a dependable single engine fighter design that was able to operate in the tropical climates of the theatre. The “N” turned out to be an epic deviation from the Thunderbolts that preceded it in that it had a longer wing span with squared off wing tips to enhance the aircrafts ability to roll. The long wings also provided the “N” model with extra fuel storage, something that was greatly needed to assist in reducing drag from hanging fuel tanks under the aircraft.
While the P-47 Thunderbolt may have to yield the title of “World War Two’s Greatest Fighter” to the North American P-51 Mustang, it is without doubt that the Thunderbolts from Farmingdale, New York made a great and noble contribution to the effort by being fast, effective, rugged and dependable. Jugs were responsible for 3,752 kills in the European Theatre of Operations alone flying a total of 546,000 missions, many of which saw pilots return to base alive, but in airframes that were damaged beyond repair. The Jug was also produced in greater numbers than any other American fighter, with some 15,660 units produced. The Republic P-47 Thunderbolt will always be one of the most loved and cherished aircraft ever to grace the world’s skies.
The best historical WW2 novel I have read is “Good By Mickey Mouse” by Len Deighton published around 1982-83. the sub plot revolves around the simpler and cheaper to build P-51 replacing the P-47. If you find the above history of interest I would recommend giving Good By Mickey mouse a read.
Thanks a lot Dennis! I haven’t heard of that book, but I’ll look into it.
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Have you and will you be at the Reno Air Races? Dennis
Great article about a cool plane. When you go to New Jersey Motorsports Park in Millville NJ you should go to the airport next door, it was a training facility for Thunderbolt pilots in WW2, there’s a neat museum and an annual airshow…..the Thunderbolt track is so named for what happened there.
Thanks Rich! I nearly got to NJMP a few years ago to meet up with some friends that were racing bikes on the Lightining circuit. Last minute schedule conflicts led to us not linking up, but I’ve heard nothing but the absolute best about NJMP. I look very forward to getting there soon.
I went to an air show that featured a fly-by of several WWII aircraft. The P51, P40, Corsair, T38 and others all screamed and snarled as they passed. Then the P47 came, last and biggest. I prepared to plug my ears, but the plane just hummed quietly. It was as if it was big and tough enough that it didn’t need to brag!
Always happy to see another article on the Jug. My dad was a lead wing engineer at the Farmingdale plant during the war and always spoke lovingly of the . The airframe was literally designed around the huge P&W Wasp radial. Some may not be aware that some Jugs were ferried from the west coast to Guadalcanal on a carrier flight deck, and flew off to their new airfield where they engaged in close-air support.
The Pilot’s flight instruction manual was explicit in its warning about high-altitude dog-fighting: If a bandit got on your tail, just dive! It also said that if the pilot got into trouble on the deck, it was much safer to simply belly in rather than bail out…the plane was so strong that it would plow through any and all obstructions. One actually flew through a pine forest in Germany while pursuing an enemy fighter – and returned to base with shattered chunks of tree jammed between its cylinders! Give credit too to those big Hamilton props!
Thank you very much for sharing your great anecdotes. They really add to the story.
My pleasure! It’s a shame that so few Jugs remain they are truly fantastic to see and hear in the air. Another bit that my father (a Civil Engineer by training) related was that the main wing spars, originally in a “U” shape, were doubled to form an “H” beam. This is a typical “over-engineering” process used by bridge designers. While this contributed to the considerable weight of the airframe, it also allowed the Jug to carry so much external ordinance and those eight big Browning .50s and their ammunition. No P-47 ever lost a wing from stress or fatigue, unlike the earlier Mustangs.
Thank you so much for your comments. It’s fantastic to hear about the engineering aspects of the Thunderbolt. I had a great deal of information collected on the Jug, and knew there was no way I could use it all in one article. The comments you made truly aid my article in that they give the piece life, a true pulse so to speak. I greatly appreciate you taking the time to share your knowledge on one of the greatest planes ever built.
This is a great page about the P-47! After four decades of studying the military aviation history of the World Wars, I’ve published an essay online about Seversky’s 1942 book “Victory Through Air Power” (given as my Website link). It has some details of some of the aircraft that led to the P-47, along with other aircraft and incidents of that time. I hope you enjoy it!
good Bye Mickey Mouse is a heartbreaker. Be aware.
Thanks for nice article and helpful comments!
You can also see the nicely preserved one of this great planes in an Air Museum in ?stanbul, Turkey.
It’s very near to ?stanbul Atatürk Airport, if you find an opportunity, i strongly advise to visit!
Being the co-author of “HELL HAWKS!” a history of the 365th Fighter Group was, for me, a learning lesson about the P-47 Thunderbolt and the men who maintained and flew the most numerous American fighter of World War II. No other fighter was as capable in the air-to-ground role, as we learned painfully in Korea in 1950 when we had to do the job with the Mustang. “HELL HAWKS!” was an attempt to win some recognition for the P-47 pilots and ground crews who went ashore on the European continent and fought on the ground. These men were right alongside the ground troops in the Battle of the Bulge.