A10 THUNDERBOLT II FOREVER?

The Faichild-Republic A10 entered service in USAF in 1976 and it is becoming one of the longest living combat aircrafts in USAF, second only to the mighty B52, maybe. The A10 is a single mission aircraft, conceived specifically to give massive support to the ground troops thanks to its ability of wiping out armored vehicles, from light troop combat carriers to heavy battle tanks. For this purpose, a specific weapon was conceived, a 30mm seven barrel rotary cannon capable of more than 4,000 rounds per minute, code name GAU 8 Avenger. Everything is extreme about this cannon. Including the same project of the airframe, that was conceived around the cannon, and not the other way around, with the front end of the seven barrels protruding thru the nose of the A10. The A10 was designed to make it the most effective ground attack plane in the world, with enormous killing capability. For this purpose, speed was not a priority, while stability and low speed control are. Thus the wings are straight and the propulsion is generated by a pair of General Electric TF34-GE-100A turbofans capable of 41 kN thrust. The TF34-GE is short, 2500 mm length, and fat, 1330 mm diameter, and was specifically conceived to generate low noise and infrared signature while delivering low fuel consumption and high static thrust. These characteristic made it very appropriate for a ground attack plane that was supposed to carry a very heavy weapons load, in excess of 7,000 kilos, while coming on the target almost unnoticed and would not get easily noticed by the infrared sensors of shoulder fired anti-aircraft missiles. Electronic countermeasures and flares assist the A10 to dodge the fire from the ground. But most important is that the A10 is extensively armored in its vital points with plates of titanium.  A real flying tank with tank-destroyer ability by a burst of its GAU8 8 cannon. The A10 is 16.26 meters long and its wings span 17.53 meter, wing area is 47.0 square meters. With an empty weight of about 25,000 pounds, it can reach a maximum of 47,100 pounds when fully loaded for close air support missions, but maximum takeoff weight should not exceed 46,000 pounds, which means that in case of full CAS mission weapons load, it needs to refuel in flight. Combat range is around 460 km, according to the mission. Its top speed barely exceeds 700 km/h, while climb rate is 6,000 feet/min. Not a thoroughbred but a very solid workhorse, since it can carry an impressive variety of bombs, missiles and rockets thanks to its 11 hardpoints, four under each wing and three under the fuselage. Plus the GAU 8 cannon. Speed and agility are the only real limits of this very capable plane, which is appreciated by a large percentage of its pilots who have been able to learn to live with those limits, while getting the best out of their machine. Thru the years, the skies have grown more hostile, especially at the levels the A10 is requested to operate and the demand for a duly evolved attack plane is rational. The debate concerning the development of an appropriate replacement for the A10 has run thru the USAF Command corridors for years, but for now only relatively minor upgrades have been applied to the basic A10. A completely new project would cost time and lots of money and this is the main reason why plans for a replacement for the A10 have been cancelled. But it might be worth to check what is in the drawers of the aeronautical industry to see if there are opportunities for smart recoveries and adaptations of previous projects, since this would cut both development time and costs. From the late years ’50, the aero industry has produced wonderful, accessible planes prior to the era of the super sophisticated today’s aircrafts. One name comes naturally in mind: F4 Phantom. Not stealth, not hyper electronics, still human, but tough like hell and immensely versatile and capable. To keep that great project in flight, Boeing developed the Super Phantom by replacing the venerable GE J79s with a pair of PW1120 turbofans and adding a large, semi-conformal belly pod. Israel tested similarly re-motorized F4 that proved capable of flying supercruise, just to prove how good that airframe was. And the F4 was not the only very good project of those times. There was a whole generation of outstanding attack aircrafts that proved their great capabilities where it counts: in combat, from the little zapper A4 to the superb A5 Avenger. And the project of the Avenger shows a number of marks that might inspire the development of a derivative that would retain the potential of the A10, but with a lot more in reserve.

The A5 Avenger  was intended to be a carrier based, supersonic nuclear bomber and it was one of the most outstanding planes in its class. It was Mach 2 capable and back in 1960 it set a 27,874 meter altitude record with a 1.0 ton bomb load. Its aerodynamic design was superb and made it a very fast, agile flyer and a very stable combat platform. It never played the role it was intended for, but in VietNam it participated in ground attack and in medium level bombing missions, while its RA5 variant was an excellent reconnaissance plane. Taking the A5 Vigilante into a comparison with the A10, the A5 is longer at 23.32 meters, but wings span a similar 16.16 meter and measure a more generous, 65.1 sq. meters, area. Empty weight was 32,783 pounds while maximum take-off weight was established at 63.085 pounds.  The A5 Avenger is somewhat bigger and substantially heavier, but this is also due to its much more relevant, 1804 km, combat range and consequent fuel load. The A5 was Mach 2 capable and its climb rate was a very respectable 8,000 ft./min. Its combat load capability included one nuclear bomb in the bomb bay and two 2000 pounds bombs in underwing hardpoints.

The A10 and A5 might have so little in common that it might not be worth going any further. But the A5 Avenger was very capable and its basic project offers some very consistent opportunities to adapt it to cover the same kind of mission of the A10, plus much more. The A5 Avenger airframe features a unique, tunnel shaped bomb bay running from behind the cockpit all the way to the rear end, with the B27, B28 or B43 nuclear bombs jettisoned from an appropriate opening in the tail .

The tunnel bomb bay appears large enough to be converted to host the mighty GAU8 cannon in a duly reinforced section that would contain the mechanical and electrical components of the cannon, plus a large reserve of ammunitions, while the firing section of it, the 7 rotary barrels, would hang right under the fuselage, with their axis duly aligned to that of the fuselage. The firing section of the cannon would be protected by a semi-conformal belly pod.  Wing profile might get updated and the wing structure should be strengthened in order to allow the adoption of more hardpoints for more underwing missile and bomb loads. If necessary, wing span might be extended and leading edge allow angle reduced to further improve low speed control. Propulsion needs a total revision since the new mission would not need Mach 2 speed. The legendary J79 must be replaced by non-afterburning turbofans of the latest generation.

General Electric F118 GE (General Electric F 118 GE)  is officially out of production, after serving very positively on the B2 and on the latest version of the U2. But basically the F118 is the non-afterburning derivative of the mighty F110GE. The F118-100 generates a maximum thrust of 85 kN, while the J79-17 delivered 80 kN on afterburning. The F118 is 240 kilos lighter and much more sober. The F118GE should be more than adequate to make the refurbished A5 capable of transonic speeds and of a payload superior to that of the A10. In case the F118-100 were not available, or a higher level of performance were demanded both in terms of payload and of speed, the Pratt & Whitney PW9000 would grant blinding potential with its 120 kN dry thrust. Basically, the PW9000 is the non-afterburning version of the Pratt & Whitney F135 (P&W F135), the most powerful military turbofan in production today, powering the F35.

Even in non-afterburning edition remain an incredibly capable engine that would grant supercruise capability to the sleek A5. The PW9000 will power the new Northrop B21 stealth bomber. With either propulsion systems, the A5 would be able to carry a heavier payload than the A10, farther and faster. Its long tunnel bomb bay can host a variety of weaponry in alternative to the GAU 8. One of the most attractive might be a retractable, large capacity multi barrel rocket launcher and related reloading system.  A large number of 5.0 inch Zuni rockets could be stored, offering massive kill capability against armor, fortified boxes and also combat ships: a salvo of five Zuni rockets would cause final damages up to destroyer class ships. A much larger number of 70mm Hydra rockets would be available for deadly attacks against light vehicles and ground troops. Laser guided bombs and air to ground missiles in underwing harpoint would complete the battle equipment.  Compared to the A10, this hypothetical re-edition of the A5 would be capable of relevant air-to-air capabilities, thanks to its superior speed, acceleration and advanced aerodynamics. Four Sidewinder air-to-air missiles would grant good fighting capabilities. North American A% has been out of production for decades, nothing is left, but the drawings of a very remarkable project. In terms of cost reduction, that is better than starting from a blank sheet of paper. A very capable plane is always worth working on to extract new potential and capabilities thru the competent application of the latest technologies. The resurrected A5 would not be stealth, but the adoption of latest generation non afterburning turbofans of the latest generation would grant impressive combat load and very high speed, and up there speed is still a weapon, though out of fashion according to the super stealth tech fans. The A5 would require a number of modifications, but it is a solid platform and very versatile thanks to its unique structure. The adoption of the latest avionics is the logic solution to make it a very effective attack aircraft up to the years 2060s. Its big nose can host a very potent and very advanced radar and a fire control system of extreme efficacy even in case of attacks at high speed that would increase it survivability in a crowded scenario. Its excellent aerodynamics and unique inner structure are two objective factors that keep its project worth a investigation. All the modifications and hi-tech addition listed might make it cost like a brand new project and that alone is enough to kill the whole idea. But I doubt it would, and the addition of today’s technology and components can really get it back into business. Only the pilots can draw the final conclusion and emit the sentence, them alone. Not the brass.