The ARES "Agile Responsive Effective Support") Model 151 aircraft was developed and built by Scaled Composites of the United States to an Army specification calling for a low-cost, high-return Close-Air Support (CAS) combat platform (under the "Low Cost Battlefield Attack Aircraft" (LCBAA) initiative). Work on the design was begun in 1981 and eventually involved the Rutan Aircraft Factory with the attempt to bring together the best known qualities of current-generation CAS aircraft to find the perfect mating of low-altitude, long-endurance, combat agility, performance, short-field / rough-field capabilities and firepower.
Burt Rutan's Scaled Composites brand was used to build the needed flyable specimen, which it did, as the Model 151. It was used solely as a technology demonstrator over its service life to prove certain concepts of the new CAS aircraft sound which, in its original form, evolved around a canard-equipped, pusher-configured turboprop-powered platform armed with a massive 30mm rotary cannon. Its over-battlefield role, given this time in history, would have been neutralization of Soviet-originated tanks and vehicles as well as concentrations of enemy troops and convoys.
Before long, the turboprop approach was superseded by a more proven Pratt & Whitney Canada (PWC) JT15D-5 turbofan engine of 2,950lb thrust output offering considerable performance gains. A first flight of this aircraft was finally recorded on February 19th, 1990 though Scaled Composites would only build one flyable example to the standard.
The prototype was armed ultimately with a smaller-caliber (though no less potent) 25mm GAU-12/U series Gatling-style internal gun and this weapon system was tested actively aboard the aircraft with good results. With this armament fitted along the nose's starboard side, an intake was set to portside to aspirate the turbofan engine - and thus keep it clear of any gasses expelled from the powerful rotary weapon. Other armament options (to be held across multiple external pylons) were unguided rockets and the AIM-9 "Sidewinder" and AIM-92 "Stinger" families of short-ranged Air-to-Air Missiles (AAMs).
Despite the unorthodox asymmetric approach given to the gun and engine fits, the ARES took on a largely conventional arrangement elsewhere about its design incorporating the cockpit at the nose and the engine exhaust port at the rear. Twin vertical tailplanes were held on short tail booms and the aircraft lacked true elevator planes. The wing mainplanes were low-mounted and set near midships in the usual fashion. Canards, small forward-set wings, were seated high along the sides of the forward fuselage section quite near the aft area of the cockpit. The sole pilot sat under a single-piece, unobstructed bubble canopy which gave excellent vision out-of-the-cockpit. Ground-running was accomplished through a traditional wheeled / retractable tricycle landing gear arrangement.
As tested, the Model 151 managed a maximum speed of 466 miles per hour with a listed combat radius of 690 miles. Its service ceiling peaked at 35,000 feet.
Despite interest on the part of the U.S. Department of Defense during the early-going of the program, the Model 151 was completed as a private venture by Scaled Composites with little help from the military. It managed to meet and exceed its testing requirements and completed some 250 hours in the air before seeing storage. It was flown one more time in March of 2008 and is currently offered by the company as a research platform. Of course there were United States Air Force (USAF) authorities who actively worked against the ARES program and there stood elements of the Army who were also interested in protecting the Hughes AH-64 attack helicopter in its given over-battlefield role. The USAF currently enjoys the fixed-wing CAS role with its aging stock of Fairchild A-10 "Thunderbolt II" attackers. The AH-64 takes on the rotary-wing CAS role in turn.