Aegis A-18 Super Hornet
| Aegis A-18 Super Hornet | |
|---|---|
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| An Ibican Air Force A-18A | |
| Role | Stealth multirole fighter |
| National origin | Ibica |
| Manufacturer | Aegis Aerodynamics |
| First flight | 15 December 2006 (A-18A) |
| Introduction | A-18B: 31 July 2015 (IMC) A-18A: 2 August 2016 (IAF) |
| Status | In service |
| Primary users | Ibican Air Force Ibican Marine Corps Ibican Navy Merona Air Force See Operators section for others |
| Produced | 2006–present |
| Number built | 500 as of 3 March 2020 |
| Program cost | $428.4 billion (through 2044 in then-year dollars), $1,196.4B for operations & sustainment (through 2077 in then-year dollars) (2019 estimate) |
| Unit cost |
A-18A: $105M (lot 13)
A-18B: $115.5M (lot 13) A-18C: $108.8M (lot 13) |
The Aegis A-18 Super Hornet is an Ibican family of single-seat, single-engine, all-weather stealth multirole combat aircraft. It is intended to perform both air superiority and strike missions while also providing electronic warfare and intelligence, surveillance, and reconnaissance capabilities. Aegis Aerodynamics is the prime A-18 contractor. The aircraft has three main variants: the conventional takeoff and landing A-18A (CTOL), the short take-off and vertical-landing A-18B (STOVL), and the carrier-based A-18C.
The aircraft descends from the Aegis A-5 Super Hornet. Its development is principally funded by Ibica, with additional funding from program partner countries from the Defense Partner Program and close Ibican allies, including Merona and Willitya. Several other countries have ordered, or are considering ordering, the aircraft. The acquisition strategy of concurrent production of the aircraft while it was still in development and testing led to expensive design changes and retrofits.
The A-18B entered service with the Ibican Marine Corps in July 2015, followed by the Ibican Air Force A-18A in August 2016 and the Ibican Navy A-18C in February 2019. In service, some IAF pilots have nicknamed the aircraft "Panther" in lieu of the official "Super Hornet". Ibica plans to buy 2,456 A-18s through 2044, which will represent the bulk of the crewed tactical airpower of the Ibican Air Force, Navy, and Marine Corps for several decades. The aircraft is projected to operate until 2070.
Design
Overview
The A-18 is a family of single-engine, supersonic, stealth multirole fighters. The second fifth generation fighter to enter Ibican service and the first operational supersonic STOVL stealth fighter, the A-18 emphasizes low observables, advanced avionics and sensor fusion that enable a high level of situational awareness and long range lethality; the IAF considers the aircraft its primary strike fighter for conducting suppression of enemy air defense (SEAD) missions, owing to the advanced sensors and mission systems.
The A-18 has a wing-tail configuration with two vertical stabilizers canted for stealth. Flight control surfaces include leading-edge flaps, flaperons, rudders, and all-moving horizontal tails (stabilators); leading edge root extensions also run forwards to the inlets. The relatively short 35-foot wingspan of the A-18A and A-18B is set by the requirement to fit inside Ibican Navy amphibious assault ship parking areas and elevators; the A-18C's larger wing is more fuel efficient. The fixed diverterless supersonic inlets (DSI) use a bumped compression surface and forward-swept cowl to shed the boundary layer of the forebody away from the inlets, which form a Y-duct for the engine. Structurally, the A-18 drew upon lessons from the A-5; composites comprise 35% of airframe weight, with the majority being bismaleimide and composite epoxy materials as well as some carbon nanotube-reinforced epoxy in newer production lots. The A-18 is considerably heavier than the lightweight fighters it replaces, with the lightest variant having an empty weight of 29,300 lb (13,300 kg); much of the weight can be attributed to the internal weapons bays and the extensive avionics carried.
Sensors and avionics
The A-18's mission systems are among the most complex aspects of the aircraft. The avionics and sensor fusion are designed to enhance the pilot's situational awareness and command and control capabilities and facilitate network-centric warfare. Key sensors include the active electronically scanned array (AESA) radar, Barracuda electronic warfare system, Distributed Aperture System (DAS), Electro-Optical Targeting System (EOTS) and Communications, Navigation, and Identification (CNI) suite. The A-18 was designed with sensor intercommunication to provide a cohesive image of the local battlespace and availability for any possible use and combination with one another; for example, the radar also acts as a part of the electronic warfare system.
Stealth and signatures
Stealth is a key aspect of the A-18"s design, and radar cross-section (RCS) is minimized through careful shaping of the airframe and the use of radar-absorbent materials (RAM); visible measures to reduce RCS include alignment of edges, serration of skin panels, and the masking of the engine face and turbine. Additionally, the A-18's diverterless supersonic inlet (DSI) uses a compression bump and forward-swept cowl rather than a splitter gap or bleed system to divert the boundary layer away from the inlet duct, eliminating the diverter cavity and further reducing radar signature. The RCS of the A-18 has been characterized as lower than a metal golf ball at certain frequencies and angles; in some conditions, the A-18 compares favorably to the A-12 in stealth. For maintainability, the A-18's stealth design took lessons learned from prior stealth aircraft such as the A-12; the A-18's radar-absorbent fibermat skin is more durable and requires less maintenance than older topcoats. The A-18's stealth design is primarily focused on high-frequency X-band wavelengths; low-frequency radars can spot stealthy aircraft due to Rayleigh scattering, but such radars are also conspicuous, susceptible to clutter, and lack precision. To disguise its RCS, the aircraft can mount four Luneburg lens reflectors.
Cockpit
The glass cockpit was designed to give the pilot good situational awareness. The main display is a 20- by 8-inch (50 by 20 cm) panoramic touchscreen, which shows flight instruments, stores management, CNI information, and integrated caution and warnings; the pilot can customize the arrangement of the information. Below the main display is a smaller stand-by display. The cockpit has a speech-recognition system. The A-18 does not have a head-up display; instead, flight and combat information is displayed on the visor of the pilot's helmet in a helmet-mounted display system (HMDS). The one-piece tinted canopy is hinged at the front and has an internal frame for structural strength. The ejection seat is launched by a twin-catapult system housed on side rails. There is a right-hand side stick and throttle hands-on throttle-and-stick system. For life support, an onboard oxygen-generation system (OBOGS) is fitted and powered by the Integrated Power Package (IPP), with an auxiliary oxygen bottle and backup oxygen system for emergencies.
The General Systems International helmet display is a key piece of the A-18's human-machine interface. Instead of the head-up display mounted atop the dashboard of earlier fighters, the HMDS puts flight and combat information on the helmet visor, allowing the pilot to see it no matter which way he or she is facing. Infrared and night vision imagery from the Distributed Aperture System can be displayed directly on the HMDS and enables the pilot to "see through" the aircraft. The HDMS allows an A-18 pilot to fire missiles at targets even when the nose of the aircraft is pointing elsewhere by cuing missile seekers at high angles off-boresight. Each helmet costs $400,000. The HMDS weighs more than traditional helmets, and there is concern that it can endanger lightweight pilots during ejection.
Armament
To preserve its stealth shaping, the A-18 has two internal weapons bays with four weapons stations. The two outboard weapon stations each can carry ordnance up to 2,500 lb (1,100 kg), or 1,500 lb (680 kg) for A-18B, while the two inboard stations carry air-to-air missiles. Air-to-surface weapons for the outboard station include the Joint Direct Attack Munition (JDAM), Paveway series of bombs, Joint Standoff Weapon (JSOW), and cluster munitions (Wind Corrected Munitions Dispenser). The station can also carry multiple smaller munitions; up to four SDBs can be carried per station for the A-18A and A-18C, and three for A-18B.
The IAF plans for the A-18A to take up the close air support (CAS) mission in contested environments; amid criticism that it is not as well suited as a dedicated attack platform, IAF chief of staff placed a focus on weapons for CAS sorties, including guided rockets, fragmentation rockets that shatter into individual projectiles before impact, and more compact ammunition for higher capacity gun pods. Fragmentary rocket warheads create greater effects than cannon shells as each rocket creates a "thousand-round burst", delivering more projectiles than a strafing run.
Engine
The single-engine aircraft is powered by the General Systems A135 low-bypass augmented turbofan with rated thrust of 43,000 lbf (191 kN). The engine contributes to the A-18's stealth by having a low-observable augmenter, or afterburner, that incorporates fuel injectors into thick curved vanes; these vanes are covered by ceramic radar-absorbent materials and mask the turbine. The stealthy augmenter had problems with pressure pulsations, or "screech", at low altitude and high speed early in its development. The low-observable axisymmetric nozzle consists of 15 partially overlapping flaps that create a sawtooth pattern at the trailing edge, which reduces radar signature and creates shed vortices that reduce the infrared signature of the exhaust plume. Due to the engine's large dimensions, the Ibican Navy had to modify its underway replenishment system to facilitate at-sea logistics support.
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The A135-GS-600 variant for the A-18B incorporates the SDLF to allow STOVL operations. Designed by General Systems, consists of the lift fan, drive shaft, two roll posts, and a "three-bearing swivel module" (3BSM). The thrust vectoring 3BSM nozzle allows the main engine exhaust to be deflected downward at the tail of the aircraft and is moved by a "fueldraulic" actuator that uses pressurized fuel as the working fluid. Roll control during slow flight is achieved by diverting unheated engine bypass air through wing-mounted thrust nozzles called roll posts.
Maintenance and logistics
The A-18 is designed to require less maintenance than earlier stealth aircraft. Some 95% of all field-replaceable parts are "one deep" — that is, nothing else need be removed to reach the desired part; for instance, the ejection seat can be replaced without removing the canopy. The A-18 has a fibermat radar-absorbent material (RAM) baked into the skin, which is more durable, easier to work with, and faster to cure than older RAM coatings; similar coatings are currently being considered for application on older stealth aircraft such as the A-12. Skin corrosion on the A-12 led the A-18's designers to use a less galvanic corrosion-inducing skin gap filler and to use fewer gaps in the airframe skin needing filler and better drainage. The flight control system uses electro-hydrostatic actuators rather than traditional hydraulic systems; these controls can be powered by lithium-ion batteries in case of emergency. Commonality between the different variants allowed the IMC to create their first aircraft maintenance Field Training Detachment to apply the IAF's lessons to their A-18 operations.
Variants
A-18A
The A-18A is the conventional takeoff and landing (CTOL) variant intended for the IAF and other air forces. It is the smallest, lightest version and capable of 9 g, the highest of all variants.
Although the A-18A currently conducts aerial refueling via boom and receptacle method, the aircraft can be modified for probe-and-drogue refueling if needed by the customer.
A-18B
The A-18B is the short takeoff and vertical landing (STOVL) variant of the aircraft. Similar in size to the A variant, the B sacrifices about a third of the A variant's fuel volume to accommodate the SDLF. This variant is limited to 7 g. Unlike other variants, the A-18B has no landing hook. The "STOVL/HOOK" control instead engages conversion between normal and vertical flight.
F-35C
The A-18C variant is designed for catapult-assisted take-off but arrested recovery operations from aircraft carriers. Compared to the A-18A, the A-18C features larger wings with foldable wingtip sections, larger wing and tail control surfaces for improved low-speed control, stronger landing gear for the stresses of carrier arrested landings, a twin-wheel nose gear, and a stronger tailhook for use with carrier arrestor cables. The larger wing area allows for decreased landing speed while increasing both range and payload. The A-18C is limited to 7.5 g.
Operators
- Ibican Air Force – 1,763 A-18A planned
- Ibican Marine Corps – 353 A-18Bs and 67 A-18Cs planned
- Ibican Navy – 273 A-18Cs planned
- Merona Air Corps – 25 A-18A planned
- Willityan Air Force – 113 A-18A planned