Scaled Composites ARES
Encyclopedia
The Scaled Composites ARES is a demonstrator aircraft
built by the company Scaled Composites
. ARES is an acronym for Agile Responsive Effective Support.
Jim Kreutz and Milo Burroughs requested that a study be undertaken for a Low Cost Battlefield Attack Aircraft (LCBAA), as there was a lack of adequate number of Close Air Support
aircraft to support the U.S. Army operations. It was decided that a fixed-wing aircraft with excellent maneuvering capabilities at very low altitudes and resistance to stall
would be necessary. Burt Rutan
decided to join this study and also to design an aircraft to meet the requirements.
Burt Rutan then started a two-phase program. The first phase was the preliminary design of LCBAA while in the second phase the Long EZ aircraft was developed to serve as a technology demonstrator. The original layout suggested by this study was that of a low wing, cantilever
configuration, aircraft powered by a pusher
turboprop
, and also suggested the aircraft be built around a 30 mm Gatling gun
capable of destroying most light armored vehicles
. It was decided that as much military hardware as possible would be used in the design.
After the study Burt Rutan went back to Scaled Composites and started tossing around the idea of producing such an aircraft. When a high Pentagon official promised that they would evaluate his aircraft if he built it, he began taking these ideas to the drawing board, and decided to produce a demonstrator aircraft, which was built in 1986.
By this time the aircraft had changed significantly: it had kept the low wing cantilever configuration, but now had a single Pratt & Whitney Canada JT15D-5 turbofan
engine rather than the originally proposed turboprop. The reason for this was vulnerability of the propeller to the debris kicked up by the nosewheel and high loads imposed on the propeller during hard maneuvering, reducing its efficiency.
A GAU-12/U 25 mm
rotary barreled cannon was mounted on the aircraft right side of the nose in a concave recession under the cockpit. The concave recession meant that when the gun was fired, exhaust gases would put pressure on the recession and push the aircraft's nose to the left. This innovative feature cancelled out the recoil of the large cannon, which tended to push the nose to the right. To prevent gun exhaust gases from travelling into the intake and reducing engine performance, Rutan designed what is perhaps ARES' most recognizable feature: the engine intake is mounted on the left side of the nose, directly opposite the cannon. Thrust was redirected to the centerline via a series of ducting, which also reduced the infrared signature.
After Beechcraft
sold Scaled Composites back to Rutan, he decided to finish the project with the company funds. This aircraft became known as the ARES, and first flew on February 19, 1990, piloted by Scaled Composites test pilot Doug Shane
. Since then it has flown more than 250 hours, and met all of its original design specifications for performance and range. In 1991 under US Air Force contract, the ARES 25 mm cannon was installed and put through its paces; during the test the cannon performed extremely well.
The ARES has since drawn a lot of attention from the U.S. Navy and Air Force, but it remains a private project. After an appearance in the movie Aces: Iron Eagle III
as an Me 263 fighter, the aircraft has become a research test bed available to any one wishing to pay to test new technologies with it. The aircraft was put into storage in December 2000 at the Mojave Spaceport
. After Scaled Composites became a Northrop Grumman
subsidiary, ARES was removed from storage and reactivated in early 2008, taking to the skies again on March 7, 2008.
s which enable safer flight at low altitude. The canards serve as the pitch
control and are designed so that the canard surface reaches critical angle of attack
sooner than the main wings, protecting the aircraft from stall while full roll
control is retained. The canards have a wingspan of 19.2 feet (5.85 m) and are swept 7 degrees forward so they can be placed behind the cockpit.
The main wing has a span of 35 feet (10.7 m) and a reference area of 191 sq. ft. (17.7 m2), not including the strakes. It is swept aft 16 degrees at the leading edge. The strakes are swept 49 degrees at the leading edge. These strakes, combined with a wet wing center-section area, form the bulk of the 2,200 lb (1000 kg, approximately 333 U.S. gallons) fuel capacity. The wing has conventional ailerons on the outboard trailing edge, and spoil-flaps
(similar to the dive-brake flap) on the inboard trailing edges. The ailerons are actuated by push-rods, and the spoil-flaps are hydraulically operated.
Directional stability is provided by twin boom-mounted fins, each of 18 sq ft (1.7 m²). area. Each has a cable-actuated rudder
at its trailing edge. The rudder actuation system also drives the full-time mechanical nosewheel steering for ground operations.
The engine inlet is another major unique feature of ARES. Since gun gas ingestion posed significant problems in other aircraft development programs (like A-10
), the configuration of ARES was designed to avoid this problem: the engine inlet is entirely contained on the left side of the aircraft, and the gun is installed on the right side. The inlet has a circular cross section, and is straight into the fan face. The engine is mounted slightly transversely in the fuselage, with an 8-degree misalignment from the aircraft's longitudinal axis.
The engine exhaust is turned back to the longitudinal axis by a curved composite tailpipe. A composite tailpipe was to help get the gun recoil reaction closer to the aircraft lateral center of gravity (CG) location, the gun is sub-merged as deeply as practical into the right side of the fuselage. Also, the fuselage is not centered about the aircraft centerline, but is offset to the left by three inches. This results in the firing barrel of the gun being only about 18 inches from the lateral CG. This minimizes the yaw movement caused by the recoil
of the gun.
The aircraft fuselage is almost completely made of fiberglass
composite material
installed over the foam core. The technique of making of composite aircraft fuselages has been perfected by Scaled Composites in previous aircraft.
To assure a low cost and high reliability of the components ARES primarily includes off-the-shelf aircraft systems. The engine is the Pratt and Whitney Canada JT15D with 2900 lb (13,2 kN) of thrust at sea level. The hydraulic system, used for spoiler flaps and landing gear actuation, uses a Piper Malibu hydraulic pump, which operates at 1500 psi. Instrumentation for the demonstrator consists mainly of standard general aviation equipment. In addition there is a head-up display
which currently displays only a fixed reticle to aim the gun but is capable of displaying complete data range of F-16. The pilot seats in the Universal Propulsion Company SIIIS-3ER ejection seat with zero-zero capability.
The fuel system consists of auxiliary wing tanks feeding an armored, fuselage-mounted main tank, which sits just forward of the engine and behind the firewall. The main tank can feed the engine in all attitudes. This tank is continuously refiled from the main wing tanks with no fuel management duties required of the pilot. By feeding the main tank from the two auxiliary wing tanks, the size of the fuel tank in the fuselage was effectively halved, creating a large space behind the pilot empty of any tanks or other aircraft systems. This bay had no dedicated function on the demonstrator, but was intended to be left available for any additional equipment which the Army might wish to install in the production version.
The main flight controls are completely mechanical and the engine has a backup mechanical fuel control so the aircraft can retain control even if the electrical system fails. The controls were specially designed to minimize the forces on the stick.
Beside the GAU-12 gun there are additional pylons to carry another ordnance (Hydra 70
FFAR, for example).
and 36 degree/second at 7G (the structure is limited to 8G). The corner speed is 210 kt (390 km/h) the stall speed is 78 kt (145 km/h).
Due to high fuel volume and good cruising efficiency the aircraft can have a range of 1200 nautical miles (2200 km) at altitude and long endurance.
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
built by the company Scaled Composites
Scaled Composites
Scaled Composites is an aerospace company founded by Burt Rutan and currently owned by Northrop Grumman that is located at the Mojave Spaceport, Mojave, California, United States...
. ARES is an acronym for Agile Responsive Effective Support.
Development
In 1981, the U.S. Army AviatorsUnited States Army Aviation Branch
The Aviation Branch of the United States Army is the administrative organization within the Army responsible for doctrine, manning and configuration for all aviation units....
Jim Kreutz and Milo Burroughs requested that a study be undertaken for a Low Cost Battlefield Attack Aircraft (LCBAA), as there was a lack of adequate number of Close Air Support
Close air support
In military tactics, close air support is defined as air action by fixed or rotary winged aircraft against hostile targets that are close to friendly forces, and which requires detailed integration of each air mission with fire and movement of these forces.The determining factor for CAS is...
aircraft to support the U.S. Army operations. It was decided that a fixed-wing aircraft with excellent maneuvering capabilities at very low altitudes and resistance to stall
Stall (flight)
In fluid dynamics, a stall is a reduction in the lift coefficient generated by a foil as angle of attack increases. This occurs when the critical angle of attack of the foil is exceeded...
would be necessary. Burt Rutan
Burt Rutan
Elbert Leander "Burt" Rutan is an American aerospace engineer noted for his originality in designing light, strong, unusual-looking, energy-efficient aircraft...
decided to join this study and also to design an aircraft to meet the requirements.
Burt Rutan then started a two-phase program. The first phase was the preliminary design of LCBAA while in the second phase the Long EZ aircraft was developed to serve as a technology demonstrator. The original layout suggested by this study was that of a low wing, cantilever
Cantilever
A cantilever is a beam anchored at only one end. The beam carries the load to the support where it is resisted by moment and shear stress. Cantilever construction allows for overhanging structures without external bracing. Cantilevers can also be constructed with trusses or slabs.This is in...
configuration, aircraft powered by a pusher
Pusher configuration
In a craft with a pusher configuration the propeller are mounted behind their respective engine. According to Bill Gunston, a "pusher propeller" is one mounted behind engine so that drive shaft is in compression...
turboprop
Turboprop
A turboprop engine is a type of turbine engine which drives an aircraft propeller using a reduction gear.The gas turbine is designed specifically for this application, with almost all of its output being used to drive the propeller...
, and also suggested the aircraft be built around a 30 mm Gatling gun
Gatling gun
The Gatling gun is one of the best known early rapid-fire weapons and a forerunner of the modern machine gun. It is well known for its use by the Union forces during the American Civil War in the 1860s, which was the first time it was employed in combat...
capable of destroying most light armored vehicles
Armoured fighting vehicle
An armoured fighting vehicle is a combat vehicle, protected by strong armour and armed with weapons. AFVs can be wheeled or tracked....
. It was decided that as much military hardware as possible would be used in the design.
After the study Burt Rutan went back to Scaled Composites and started tossing around the idea of producing such an aircraft. When a high Pentagon official promised that they would evaluate his aircraft if he built it, he began taking these ideas to the drawing board, and decided to produce a demonstrator aircraft, which was built in 1986.
By this time the aircraft had changed significantly: it had kept the low wing cantilever configuration, but now had a single Pratt & Whitney Canada JT15D-5 turbofan
Turbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
engine rather than the originally proposed turboprop. The reason for this was vulnerability of the propeller to the debris kicked up by the nosewheel and high loads imposed on the propeller during hard maneuvering, reducing its efficiency.
A GAU-12/U 25 mm
GAU-12 Equalizer
The General Dynamics GAU-12/U Equalizer is a five-barrel 25 mm Gatling gun-style rotary cannon. The GAU-12/U is used by the United States, Italy and Spain, which mount the weapon in their fighter jets such as the AV-8B Harrier II, airborne gunships such as the Lockheed AC-130, and land-based...
rotary barreled cannon was mounted on the aircraft right side of the nose in a concave recession under the cockpit. The concave recession meant that when the gun was fired, exhaust gases would put pressure on the recession and push the aircraft's nose to the left. This innovative feature cancelled out the recoil of the large cannon, which tended to push the nose to the right. To prevent gun exhaust gases from travelling into the intake and reducing engine performance, Rutan designed what is perhaps ARES' most recognizable feature: the engine intake is mounted on the left side of the nose, directly opposite the cannon. Thrust was redirected to the centerline via a series of ducting, which also reduced the infrared signature.
After Beechcraft
Beechcraft
Beechcraft is an American manufacturer of general aviation and military aircraft, ranging from light single engine aircraft to business jets and light military transports. Previously a division of Raytheon, it has been a brand of Hawker Beechcraft since 2006....
sold Scaled Composites back to Rutan, he decided to finish the project with the company funds. This aircraft became known as the ARES, and first flew on February 19, 1990, piloted by Scaled Composites test pilot Doug Shane
Doug Shane
Douglas B. Shane is an American test pilot and has trained as a commercial astronaut. He was a member of the Scaled Composites astronaut team and one of the test pilots for SpaceShipOne, the experimental spaceplane developed by Scaled Composites...
. Since then it has flown more than 250 hours, and met all of its original design specifications for performance and range. In 1991 under US Air Force contract, the ARES 25 mm cannon was installed and put through its paces; during the test the cannon performed extremely well.
The ARES has since drawn a lot of attention from the U.S. Navy and Air Force, but it remains a private project. After an appearance in the movie Aces: Iron Eagle III
Aces: Iron Eagle III
Aces: Iron Eagle III is a 1992 action film directed by John Glen and is the third installment of the Iron Eagle film series, with Louis Gossett, Jr. reprising his role as Col. Charles "Chappy" Sinclair. Also starring are Japanese actor Sonny Chiba and retired boxing champion Ray "Boom Boom" Mancini...
as an Me 263 fighter, the aircraft has become a research test bed available to any one wishing to pay to test new technologies with it. The aircraft was put into storage in December 2000 at the Mojave Spaceport
Mojave Spaceport
thumb|right|235px|A retired [[Boeing 767-200]] that flew for [[Ansett Australia]] being cut open for scrap at Mojave AirportThe Mojave Air and Space Port , also known as the Civilian Aerospace Test Center, is located in Mojave, California, at an elevation of...
. After Scaled Composites became a Northrop Grumman
Northrop Grumman
Northrop Grumman Corporation is an American global aerospace and defense technology company formed by the 1994 purchase of Grumman by Northrop. The company was the fourth-largest defense contractor in the world as of 2010, and the largest builder of naval vessels. Northrop Grumman employs over...
subsidiary, ARES was removed from storage and reactivated in early 2008, taking to the skies again on March 7, 2008.
Aircraft design
The ARES has quite unique shape compared to other aircraft. It incorporates canardCanard (aeronautics)
In aeronautics, canard is an airframe configuration of fixed-wing aircraft in which the forward surface is smaller than the rearward, the former being known as the "canard", while the latter is the main wing...
s which enable safer flight at low altitude. The canards serve as the pitch
Pitching
Pitching may refer to the following:* Pitch movement of aircraft, ships, propellers etc.* Baseball pitcher...
control and are designed so that the canard surface reaches critical angle of attack
Angle of attack
Angle of attack is a term used in fluid dynamics to describe the angle between a reference line on a lifting body and the vector representing the relative motion between the lifting body and the fluid through which it is moving...
sooner than the main wings, protecting the aircraft from stall while full roll
Aileron roll
The Aileron Roll is an aerobatic maneuver in which the aircraft does a full 360° revolution about its longitudinal axis. When executed properly, there is no appreciable change in altitude and the aircraft exits the maneuver on the same heading as it entered...
control is retained. The canards have a wingspan of 19.2 feet (5.85 m) and are swept 7 degrees forward so they can be placed behind the cockpit.
The main wing has a span of 35 feet (10.7 m) and a reference area of 191 sq. ft. (17.7 m2), not including the strakes. It is swept aft 16 degrees at the leading edge. The strakes are swept 49 degrees at the leading edge. These strakes, combined with a wet wing center-section area, form the bulk of the 2,200 lb (1000 kg, approximately 333 U.S. gallons) fuel capacity. The wing has conventional ailerons on the outboard trailing edge, and spoil-flaps
Spoiler (aeronautics)
In aeronautics, a spoiler is a device intended to reduce lift in an aircraft. Spoilers are plates on the top surface of a wing which can be extended upward into the airflow and spoil it. By doing so, the spoiler creates a carefully controlled stall over the portion of the wing behind it, greatly...
(similar to the dive-brake flap) on the inboard trailing edges. The ailerons are actuated by push-rods, and the spoil-flaps are hydraulically operated.
Directional stability is provided by twin boom-mounted fins, each of 18 sq ft (1.7 m²). area. Each has a cable-actuated rudder
Rudder
A rudder is a device used to steer a ship, boat, submarine, hovercraft, aircraft or other conveyance that moves through a medium . On an aircraft the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane...
at its trailing edge. The rudder actuation system also drives the full-time mechanical nosewheel steering for ground operations.
The engine inlet is another major unique feature of ARES. Since gun gas ingestion posed significant problems in other aircraft development programs (like A-10
A-10 Thunderbolt II
The Fairchild Republic A-10 Thunderbolt II is an American single-seat, twin-engine, straight-wing jet aircraft developed by Fairchild-Republic in the early 1970s. The A-10 was designed for a United States Air Force requirement to provide close air support for ground forces by attacking tanks,...
), the configuration of ARES was designed to avoid this problem: the engine inlet is entirely contained on the left side of the aircraft, and the gun is installed on the right side. The inlet has a circular cross section, and is straight into the fan face. The engine is mounted slightly transversely in the fuselage, with an 8-degree misalignment from the aircraft's longitudinal axis.
The engine exhaust is turned back to the longitudinal axis by a curved composite tailpipe. A composite tailpipe was to help get the gun recoil reaction closer to the aircraft lateral center of gravity (CG) location, the gun is sub-merged as deeply as practical into the right side of the fuselage. Also, the fuselage is not centered about the aircraft centerline, but is offset to the left by three inches. This results in the firing barrel of the gun being only about 18 inches from the lateral CG. This minimizes the yaw movement caused by the recoil
Recoil
Recoil is the backward momentum of a gun when it is discharged. In technical terms, the recoil caused by the gun exactly balances the forward momentum of the projectile and exhaust gasses, according to Newton's third law...
of the gun.
The aircraft fuselage is almost completely made of fiberglass
Fiberglass
Glass fiber is a material consisting of numerous extremely fine fibers of glass.Glassmakers throughout history have experimented with glass fibers, but mass manufacture of glass fiber was only made possible with the invention of finer machine tooling...
composite material
Composite material
Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...
installed over the foam core. The technique of making of composite aircraft fuselages has been perfected by Scaled Composites in previous aircraft.
To assure a low cost and high reliability of the components ARES primarily includes off-the-shelf aircraft systems. The engine is the Pratt and Whitney Canada JT15D with 2900 lb (13,2 kN) of thrust at sea level. The hydraulic system, used for spoiler flaps and landing gear actuation, uses a Piper Malibu hydraulic pump, which operates at 1500 psi. Instrumentation for the demonstrator consists mainly of standard general aviation equipment. In addition there is a head-up display
Head-Up Display
A head-up display or heads-up display is any transparent display that presents data without requiring users to look away from their usual viewpoints...
which currently displays only a fixed reticle to aim the gun but is capable of displaying complete data range of F-16. The pilot seats in the Universal Propulsion Company SIIIS-3ER ejection seat with zero-zero capability.
The fuel system consists of auxiliary wing tanks feeding an armored, fuselage-mounted main tank, which sits just forward of the engine and behind the firewall. The main tank can feed the engine in all attitudes. This tank is continuously refiled from the main wing tanks with no fuel management duties required of the pilot. By feeding the main tank from the two auxiliary wing tanks, the size of the fuel tank in the fuselage was effectively halved, creating a large space behind the pilot empty of any tanks or other aircraft systems. This bay had no dedicated function on the demonstrator, but was intended to be left available for any additional equipment which the Army might wish to install in the production version.
The main flight controls are completely mechanical and the engine has a backup mechanical fuel control so the aircraft can retain control even if the electrical system fails. The controls were specially designed to minimize the forces on the stick.
Beside the GAU-12 gun there are additional pylons to carry another ordnance (Hydra 70
Hydra 70
The Hydra 70 rocket is a weapon derived from the 70 mm Mk 4/Mk 40 Folding-Fin Aerial Rocket developed by the United States Navy for use as a free-flight aerial rocket in the late 1940s.-Overview:...
FFAR, for example).
Aircraft performance
The ARES has very good turning performance as a result of low wing loading. Its turn rate is 32 degree/second at 6GG-force
The g-force associated with an object is its acceleration relative to free-fall. This acceleration experienced by an object is due to the vector sum of non-gravitational forces acting on an object free to move. The accelerations that are not produced by gravity are termed proper accelerations, and...
and 36 degree/second at 7G (the structure is limited to 8G). The corner speed is 210 kt (390 km/h) the stall speed is 78 kt (145 km/h).
Due to high fuel volume and good cruising efficiency the aircraft can have a range of 1200 nautical miles (2200 km) at altitude and long endurance.