Isselmere
13-09-2005, 20:13
[This will eventually receive the same treatment as that I gave the DAS-2 Spectre, time permitting. Within this document nm refers to “nautical miles”, not nanometres.]
DAS-4 Swordfish interdiction strike aircraft
Introduction
Like the DAS-3 Sea Fury, the DAS-4 Swordfish began with an official request for proposals from the Royal Isselmere-Nieland Navy’s Fleet Air Arm (FAA). Naval Aircraft Requirement, Number 29 (NAR-29) specified an aircraft that could perform low level attack missions at either supersonic or high trans-sonic speed at ranges in excess of 800 nm (about 1500 km) carrying its main strike armament within an internal weapons bay and equipped with at least two short range self-protection missiles and with a measure of stealth.
Though there was a host of aircraft suitably conforming to some of those specifications, in particular Dat’ Pizdy Corporation’s F-225A Kestril, Avalon Aerospace Corporation’s SZ-1 Vulture and SZ-70 Valkyrie, and Praetonia’s L-82 Hussar, none entirely fit the NAR-29 requirements. The General Dynamics F-111, though with characteristics similar to those of the NAR-29, failed in terms of engine reliability and response time and had an exceptionally large radar cross-section (RCS). The electronics suite of the F-111 was also woefully obsolete. Lockheed Martin’s FB-22 fulfilled most of the NAR-29 specifications, but not that for low altitude flying: the large wing had too great a gust response.
Detmerian Aerospace Dynamics’s design, the DAS-4, did not have the speed of the Valkyrie or the Hussar or such advanced features as pulse detonation gas turbine engines or electro-thermal chemical (ETC) cannons, but it met the range and reliability requirements established by the FAA and the foreign aircraft were not as able to fly comfortably at low level. Consequently, the FAA requested that Detmerian Aerospace produce six working prototypes – the Harridan DSP.1 one-sixth scale uncrewed strike aircraft prototype, the full-scale crewed Indigenous Design Prototype, Number 31 (IDP-31), as well as four of the finalised NAR-29 prototypes.
Development
With the success of the Harridan DSP.1 and the crewed IDP-31, the NAR-29 prototypes advanced to the airframe, engine, electronics, and weapons testing phases. The first of the development aircraft, DA1, was powered by the DAS-2’s ATG-8F engines and was modestly underpowered. Still, it managed to break the sound barrier on its first flight and showed the general suitability of the DAS-4 airframe. The mission adaptable wing fitted with spoilers, full-span leading edge slats, and low-speed flaps was shown to generate sufficient lift to reduce the landing speed to an acceptable 130 knots.
DA2, with two of Isselmere Motor Works Aeronautical Division’s ATG-9F augmented low bypass ratio three-dimensional thrust vectoring twin-shaft turbofans installed, gave the NAR-29 swift engine response and more than enough power to propel the Swordfish at well over twice the speed of sound – DA2 achieved Mach 2.52 in its sixth flight. This speed was, of course, in clean condition and without the complete electronics suite of the production aircraft.
To save funds during one of the UKIN’s economic recessions, the FAA was forced to do away with DA4 and conducted both electronics and weapons testing on DA3. Electronics testing on the sensors, electronics countermeasures, and electronic support measures passed without revealing significant interference or electronic noise problems. Weapons testing indicated initial problems with the release mechanism in the internal weapons bay when operating at maximum speed, which was corrected in a subsequent software upgrade: the bay doors failed to close owing to a conflict between the fire control computer and the signature self-detection system. Once that conflict had been resolved, the DAS-4 passed into the production phase.
Construction
Airframe
The Swordfish had to be lightweight in order to ensure rapid acceleration from the ATG-9F, strong enough to transport a massive payload over a long distance, and sturdy to withstand the stresses of high speed low level flight. Modern materials science, miniaturisation, and clever engineering combined to craft the DAS-4.
In terms of materials, forty percent of the Swordfish’s weight comes from composites, thirty-eight percent from titanium alloys, ten percent from high temperature aluminium alloys, and the final twelve percent from high quality steels with low reflective indices. The composites serve several functions. A sandwich of composite honeycomb and fabric form the wings and much of the skin of the fuselage, the wings stiffened by composite spars interspersed with spars of high strength titanium alloys used primarily for the wing hardpoints. A thin layer of Hauberk composite-ballistic ceramic armour providing additional protection to the self-sealing tanks adds strength to the wings as well. Much of the composites are radar absorbent materials (RAM) that reduce the DAS-4’s large physical cross-section to a very modest RCS.
Titanium alloys are utilised in areas subject to high physical and thermal stress such as the wing folds and roots, the engine bays and within the engines themselves, and a thin layer protecting the pilots and certain key components. Aluminium alloys with improved thermal resistance are used in the remainder of the Swordfish’s skin and support structures within the aircraft itself.
Flight control is entirely digital. Like most modern combat aircraft, the DAS-4 control surfaces and systems are managed by four flight control computers that receive and transmit commands by light signals through fibre-optic cables, known commonly as fly-by-wire. Electronic commands to the control surfaces are received by the high pressure hydraulic system fed by three distributed reservoirs enabling the aircraft to react almost instantaneously to aircrew and computer input.
Although the high top speed of the Swordfish requires the use of variable incidence intakes, the reflections potentially caused by those protuberances has been kept to a minimum. The engines are hidden deep within the fuselage minimising the infra-red signature of the aircraft and vents to the final stages of the exhaust on the upper fuselage of the aircraft may be opened to further minimise emissions. Baffles further serve to mask possible radar reflections from the fan and compressor blades.
Future designs may take advantage of research conducted on new fixed intakes to minimise both the DAS-4’s radar signature and weight.
Airfoils
The Swordfish has a small wing with a small chord for an aircraft of its size. This wing gives very low gust response – that is, the DAS-4 is not as susceptible to low altitude turbulence – making low level flight far more comfortable for the aircrew than in multirole fighters whilst prolonging the airframe’s lifetime. The small wing in no way diminishes the Swordfish’s low altitude manoeuvrability. Quite the reverse, as the fly-by-wire command-to-control surface interface and direct voice input (DVI) with hands-on-throttle-and-stick (HOTAS) man-machine interface (MMI) as well as a design that is naturally unstable in subsonic flight and with superb lift-generation devices on the wings themselves make the aircraft an extremely agile and deadly low level performer.
The wings are fixed, unlike many modern strike aircraft designs. Though fuel efficiency and manoeuvrability in all flight regimes may have been sacrificed, so has the weight penalty incurred by the variable sweep mechanism. To compensate for these purported deficiencies in a fixed wing design, the wings are stronger.
Like the DAS-2, the DAS-4 has twin canted tail surfaces to maximise supersonic stability and to reduce the chance of radar return reflections and two slab all-moving tailerons or stabilisers. The tails themselves host an array of aerials for electromagnetic signals receivers and transmitters for the ALI.261 integrated countermeasures system (ICMS).
The wings and vertical tail surfaces both support self-sealing fuel tanks allowing the Swordfish to carry an incredible quantity of fuel to conduct long range operations deep into enemy territory. Indeed, fuel may comprise to thirty-six percent (10800 kg) of the DAS-4’s clean take-off weight, though usually the Swordfish takes off with 8200 kg.
Powerplant
The Swordfish’s engines are 150 kN (96.4 kN dry thrust) IMW ATG-9F augmented low bypass ratio three-dimensional thrust-vectoring turbofans that permit the aircraft to fly at Mach 2.24 or to supercruise at Mach 1.32 (clean and at altitude in both conditions). The engines are necessarily separated by a short distance in order to accommodate the fuselage weapons bay, granting some protection against both engines being disabled by a single blow whilst the ATG-9F’s thrust vectoring can minimise the difficulties of controlling the aircraft on a single engine, which can be aggravated by widely spaced engines.
The ATG-9F, like the ATG-8F, is a modular design permitting rapid exchange of damaged components rather than of entire engines. The use of powder metallurgy – which facilitates the manufacturing of single crystal structures that are more resistant to thermal stress fractures – and of blended blade-disc (blisk) fans offer exceptional weight savings and give the engine a thrust-to-weight ratio of 1:9.34.
The thrust-vectoring mechanism is that used on the ATG-8F, with a modified universal joint to direct engine thrust up to thirty degrees off the engine’s axis not simply up and down, but through a three-hundred-and-sixty degree arc, offering superb handling capabilities and the precision release of iron bombs.
Each of the ATG-9F turbofans are controlled and monitored by two AEQ.15b computers giving the pilot full-authority digital engine control (FADEC). Engine performance from each is closely monitored and recorded to prolong engine life and to ensure maximum fuel efficiency.
Electronics
General automated systems
As noted above, the Swordfish operates in accordance with pilot and computer inputs to maintain artificial stability in subsonic flight and quick reactions in all flight regimes. A quadruplex flight control system of AEP.15 computers manages the control surfaces to give the DAS-4 its surprising agility along with the four AEQ.15b computers that administer the engines. To these eight computers are a further three for fuel and stores management (AEL.15), two for the aircrew environmental control system (AEQ.11) that distributes aircrew inputs to the appropriate systems, and one for the ground crew to perform tests and evaluation of the DAS-4’s many systems. A final pair of computers – AEQ.242 threat management systems (TMS) – serve as the Swordfish’s integrated fire control and defensive systems management. All computers use dual-core processors that are capable of in-flight recovery in case of corrupted software and are monitored by built-in test and evaluation (BITE) equipment. The computers use an open architecture operating system that permits rapid in-flight updating of mission information and swift upgrading of systems and functions in the field.
The safeguards provided by redundant computers and systems monitoring are buttressed by another hardware advantage. All of the computers use gallium arsenide chips, which are more resistant to electromagnetic pulses (EMP) that silicon-based chips. Mission critical systems such as the four flight control computers are further hardened against EMP so that the Swordfish can effectively perform free-fall nuclear bombing missions if necessary.
Sensors and related systems
The DAS-4 is bristling with sensors and electronic support measures in order to perform low-level attack missions at high speed both day and night in all weathers.
First and foremost among these systems is the ARU.235 Loki multifunction radar. The Loki is a low probability of intercept active electronically scanning array (AESA-LPI) optimised for low-level operations. With over 2000 transceiver modules arranged into sub-arrays the ARU.235 permits the Swordfish to speed along at tree-top level whilst using ground mapping radar (GMR) with moving target indication (MTI) and terrain following radar (TFR) scans to successfully avoid obstacles and to navigate using terrain reference points. GMR with MTI along with synthetic aperture radar (SAR) technology allows the DAS-4 to detect surface targets, picking out even moving targets from ground clutter, including those hidden by obstacles. The low power of each transceiver module makes the ARU.235 very difficult to detect whilst being incredibly capable.
Despite the ARU.235’s main role as a surface attack system, it can make an enemy pilot’s life a misery as well. The Loki can simultaneously detect and track surface and air targets, allowing the Swordfish to prosecute foes in the air as well as on the ground. Inverse synthetic aperture radar (ISAR) technology can cut through stealth technology and electronic countermeasures, using a target’s own movement to reveal it for termination.
Enemy emitters, rather than giving the Swordfish’s foes an advantage, simply permit the DAS-4 to either avoid or attack them. The ARU.235, with sub-arrays in either operating in a active-passive mode or purely passive reception role, can detect and classify specific emitters at much greater than their detection range. Using that information, the Swordfish can respond with anti-radar or air-to-air missiles as required. Alternatively, the DAS-4 can simply sneak its way under and around those enemy radars to perform surprise strikes against heavily defended targets.
The Loki can instead use the electronic intelligence it receives to respond with electronic countermeasures (ECM) by jamming those emitters. The ARU.235 can serve as a noise or deception jammer (using range gate stealing or active cancellation) over its wide range of bandwidths (X-band and the higher end of L-band and the lower bandwidth of the K-bands).
In addition to the ARU.235, the Swordfish is equipped with a rear passive electronically scanned array (PESA), forward and rear sector optronics, and the helmet-mounted display/sight (HMDS) system.
The AVQ.71 HMDS in conjunction with direct voice input (DVI) makes the pilot-weapons system operator (WSO) team in a Swordfish an exceptionally deadly pair. The HMDS conveys information collated by the AEQ.242 and the AEQ.11 computers to the aircrew in simple to understand symbology permitting rapid response to threats and targets of opportunity without having to divert their attention to the HUD or other displays. The AVQ.71 is fitted with night vision equipment (NVE) giving the aircrew full visibility during night missions.
Target cueing using the AVQ.71 is achieved either through DVI or by depressing a button on the control relay mechanisms such as the control stick and throttle or the WSO’s joysticks. The pilot or WSO maintains the object of interest – which need not be an object presently detected by either the sensors or the ESM – in sight until it is noted by a targeting caret. Noting of previously unidentified objects can occur within milliseconds, depending on the object in question.
The DVI system at present has a vocabulary of approximately 500 words attuned to the speech patterns of the aircrew. This working dictionary is usually developed over several training missions and is stored in secure, transferable data transfer devices.
Size restrictions necessitated the use of a PESA rather than an AESA in the aft quarter, but the ARQ.284 can still perform most of the functions of a shorter ranged version of the ARU.235. The X-band PESA usually serves as a passive receiver for enemy interceptor radars though it may be used to provide a short sharp burst of radio waves to overwhelm the seeker heads of active radar homing missiles. Doing so does severely diminish the service life of the unit and may cause damage to friendly radars, but line replaceable units (LRU) and shop replaceable items (SRI) are far easier to exchange than aircrew. The range of the ARQ.284 against small fighter-sized targets is approximately 60 km in active tracking mode.
The Swordfish sports a wide assortment of optronics as well. Its forward optronics array consists of an AAS.233 infra-red search-and-track (IRST) turret and an APQ.240 multifunction detection and ranging array. The IRST can passively acquire and track air and surface targets or to assist in low-level navigation day or night in all weather conditions. In low-light and nighttime conditions, the AAS.233 may feed its view to the aircrew’s HMDS or other displays.*
Should the AAS.233 be rendered inoperable, a GWS.65Aa Kite infra-red missile seeker head may be used as an IRST.
The APQ.240 consists of an AJS.229 laser designator/range-finder (LDRF) and an AVS.230 low-light capable charge-coupled device (CCD). Unlike the APQ.240 on the Spectre, that on the Swordfish is chin-mounted to identify and illuminate ground targets. Imagery from the APQ.240 may likewise be forwarded to the HMDS or other displays.
In the rear sector, the Swordfish has tail-mounted aerials for the AAS.243 infra-red (IR) search arrays to detect incoming missiles and approaching fighters as well as two further low-light level capable CCDs used primarily for battle damage assessment (BDA). The AAS.243 has entered a new age of usefulness with the introduction of the new rear-firing missile hardpoints: in air exercises, a number of fighter pilots have been “destroyed” by supposedly vulnerable Swordfish.
Threat management
To attack the most heavily defended targets and protect itself against foes determined to remove it from the sky, the Swordfish has been given a threat management suite capable to detecting and defeating a broad variety of enemy systems.
The basis of the AEQ.242 threat management system (TMS) are two computers that compile the immense volume of data coming from the active and passive arrays detailed above, such as the ARU.235 and the AAS.243, as well as the receiver systems, notably the ALR.217 radar warning receiver (RWR) and ALR.218 laser warning receiver (LWR) arrays that detect and home on emitters, and the missile approach warning system (MAWS), comprising of the AAR.219 missile plume detector and the ALR.227 launch warning indicator arrays that monitor radiated radio and infra-red energy coming from emitters and launchers as well as the missiles themselves.
Data to the AEQ.242 comes from the DAS-4’s identification and classification systems as well. The AUX.254 combined interrogator transponder (CIT) is the Swordfish’s identification friend or foe (IFF) aerial. The CIT set uses beam steering not only to identify whether a bogey or land unit is friendly or hostile, but may provide additional targeting data such as altitude and speed as well. The AMX.255 target recognition system (TRS) vets both returned queries from the CIT or by other IFF units as well as from the DAS-4’s radar, infra-red, and optical sensors and emission receivers, cross-referencing that data with information within its threat library. New threats may be catalogued in-flight by the AMX.255 and passed along to fellow flight members using a secure datalink (covered below).
With this information, the AEQ.242 presents the aircrew with a concise but thorough visual description of known threats through the HMDS as well as the HUD and head-down displays as desired by the aircrew. This allows the Swordfish to navigate around the worst threats as well the means by which to foil the others.
Should avoidance not be possible, the Swordfish has an elaborate countermeasures suite, starting with the ALQ.228 self-protection jammer (SPJ). The ALQ.228 is capable of receiving a broad spectrum of radio bandwidths and of countering the most commonly used surface-to-air missile (SAM) control and fighter radars and of noise and deception jamming on the S, L, and X-bands – an expanded capability model is currently in service with the RINN and the JGN – as well as a limited capacity to jam communications.
If the ALQ.228 SPJ and the ARU.235 and ARQ.284 radars fail to dissuade an enemy attack, the Swordfish can respond with an assortment of expendable countermeasure decoys. Though not an integral part of the DAS-4, the ALQ.220 Flamingo autonomous aerial decoy is certainly the cornerstone of the aircraft’s defence. Equipped with a modest laser ring gyro inertial navigation system (LINS), a secure datalink relay with the launching aircraft, a radar reflector and a small set of short range warning receivers of its own, the 250 kg Flamingo adopts the flight characteristics of the launching aircraft. The Flamingos may be used to feint in an alternative direction or to fill the sky with a host of alternative, more seductive radar targets for active radar guiding missiles and air defence radars. The Swordfish usually carries three ALQ.220 during strike missions. Flamingos with improved infra-red deception capability will be entering service in the near future.
Next in the DAS-4’s arsenal of deception is the ALE.212 towed deception decoy (TDD) unit. The Swordfish sports two three-cell ALE.212 units on its wingtips. When released, the ALE.212 decoys trail one hundred metres (100 m) behind the DAS-4 on thermally insulated fibre-optic cables capable of withstanding +6/-3 g manoeuvres. Connected to the ALI.261 integrated countermeasures system (ICMS) by the fibre-optic cable, the decoy may be configured in flight to counter specific incoming threats, forcing SAM and air-to-air missiles to detonate prematurely. There are two models of the ALE.212 decoys: the ALE.212a radar decoy and the ALE.212b IR decoy. The ALE.212b has just entered RINN and RINAF service and will soon be appearing in JGN aircraft. It emits pulses of IR radiation invisible to the naked eye to fool even the more discerning IR-seeking missiles.
When even the ALE.212 fails, the Swordfish still has six 32-cell ALE.209 expendable aerial countermeasures ejectors (EACME) for chaff canisters and flares. Improved radar and IR decoys – including non-incandescent ‘flares’ – capable of fooling even modern highly sensitive missile seeker heads may be used as well and are currently in service with the UKIN-DF.**
The ALI.261 ICMS manages all of these varied countermeasure systems. The ICMS may be configured to operate entirely autonomously of aircrew-input, in conjunction with pilot or WSO commands, or strictly in accordance with aircrew input. Effectively a sub-system of the AEQ.242, the software of the two systems and that of the AMX.255 – another AEQ.242 sub-system – has been rigorously tested to avoid command conflict. The aircrew is thus left only with an incredibly clear picture of their flying environment.
Communications
The communications equipment on the Swordfish is diverse, covering the HF to UHF bands as well as the S- and L-bands. All of the radios aboard the DAS-4 are designed to operate over secure channels, although for intercepts of civil aircraft, open channels may be used. There is a secure satellite communications aerial for the embedded global positioning satellite (GPS) system and to maintain contact with higher echelons as well.
Yet the most common means of communication between flight mates and uncrewed aerial vehicles (UAV) is through multi-function information distribution systems (MIDS) or datalinks. The Swordfish is equipped with two datalinks. The CSZ.17Ab general purpose datalink allows the DAS-4 to communicate with fellow flight members or with similarly equipped aircraft. The ASP.259 provides tactical control to UAV, which the WSO or the pilot may use to reconnoitre targets or to provide a diversion or additional support. With both systems, the Swordfish can coordinate devastating attacks and mutual support against the enemy, overwhelming him or her with aerial targets and overwhelming firepower.
Navigation
The ARU.235 Loki is a multipurpose low probability of intercept active electronic scanning array (AESA-LPI) optimised for low-level operation and attack, offering Swordfish crews superlative information for nape-of-the-earth (NOE) flight in all conditions, day or night. The ARU.235’s ground mapping and terrain following functions (GMR and TFR) use synthetic aperture radar (SAR) technology to identify targets that might otherwise be hidden by obstructions. Along with the AMN.252 hybrid navigation system (HNS) – comprising of an AJN.249 laser ring gyro inertial navigation system (LINS) and an AUN.250 embedded GPS system – the ARU.235 provides the Swordfish crew with terrain profiling and matching (TERPROM) capability managed by the AEN.256 computer, allowing the aircraft to fly accurately, safely, and with the minimum of electronic emissions over dangerous terrain.
With the ARU.235’s ability to act as a passive receiver for enemy radars allow the Swordfish to keep below enemy air defences while not endangering the crew. The TFR system delivers information immediately to the head-up display and the helmet mounted display/sight (HMDS) system permitting the pilot to retain perfect situational awareness. The TFR may be used to automatically correct the aircraft’s flight path to counter obstacles or enemy air defences. The Loki uses synthetic aperture radar technology to assign optimal attack vectors, ingress and egress points, as well as to define otherwise unseen targets.
As well as these systems, the Swordfish sports aerials for an LPI millimetric wavelength Doppler radar altimeter, tactical air navigation (TACAN), and an instrument landing system (ILS). But devices are not the end to the DAS-4’s navigational avionics.
The Swordfish is equipped with a superlative autopilot and microwave landing system (MWLS) that allows for complete automatic control of flight operations from wheels up to touchdown. The ASP.263 autopilot in automatic gun aiming mode combines data from the ARU.235 and the front sector optronics (AAS.233 and the APQ.240) with that from the AEP.15 flight control computers to give the DAS-4 a one-shot kill capability with the ACA.41 automatic cannon.
Cockpit
The cockpit stations for the pilot and the WSO are dominated by polychromatic active matrix liquid crystal displays (AMLCD). The so-called glass cockpits present flight data, threat information, and targeting solutions to the aircrew using easy to understand symbols, minimising the need to hunt for this or that steam gauge-style instrument. The pilot also has use a large, wide-angle HUD that may be disengaged in preference to the HMDS. The WSO’s station has been optimised for sensor and weapons control with additional mechanisms to facilitate UAV control.
The arrangement of the displays was arrived at after much ergonomic testing for ease of use and interpretation whilst in the midst of aerial combat.
Stores
The aircraft has an internal weapons bay has been stressed for 2500 kg with room enough for two 1000 kg precision guided munitions (PGM) such as laser guided bombs (LGB). Two smaller internal missile bays are located on the side of each air intake. Each missile bay may carry either one medium-sized beyond visual range missile such as the AIM-120C AMRAAM or the GWS.74A Kestrel or two intermediate-to-short range missiles such as the AIM-9X Sidewinder, the ASRAAM, the IRIS-T, or the GWS.65A Kite. The Swordfish sports an ACA.41 30 x 173mm automatic cannon with 250 rounds capable of accurately striking targets at almost two kilometres (1.83 km to be precise) that is still quite deadly against some armoured vehicles.
The fuselage bears three external hardpoints as well. After the recent air battles in Inkana, two further recessed hardpoints for rear-firing intermediate-range missiles were added to provide the aircraft with rare off-boresight killing capability. The recesses, designed for GWS.65A missiles, but which may be altered to conform to the short-to-intermediate range missiles used by the purchasing nation, generate very little additional drag when the missile is in place. A piston safely propels the missile from the aircraft before the motor ignites. The final fuselage hardpoint is aft of the weapons bay and fore of the arrestor hook. This centreline hardpoint primarily serves to launch ALQ.220 Flamingo autonomous deception decoys, although it may be used to carry one ALQ.222 Finch electronic countermeasures pod.
Atop each wing-root are connections for two large (2700-litre) conformal fuel tanks (CFT) or additional avionics. The CFT and the internal weapons bays permit the Swordfish to prosecute targets at extreme range with minimal drag or radar cross-section (RCS) penalties. The CFT have been constructed to withstand the entire range of the DAS-4’s flight envelope whilst the internal weapons bay can maintain its integrity to over +7/-3 gravities (g) sustained.
Each wing has four hardpoints. The two innermost hardpoints on each wing are each stressed to carry 3000 kg in flight regimes of greater than +6/-3 g sustained. The outer two hardpoints on each wing have been stressed for 575 kg (inner) and 400 kg (outermost). The outermost pylon has been wired for the launching of the ALQ.220 Flamingo decoy.
In terms of weapons functionality, the Swordfish can easily carry most aerial weapons systems currently produced by Lyme and Martens Industries – with the sole exception of the massive GWS.58A Hurricane long-range surface attack missile -- and may easily be configured to fire a very wide assortment of other devices.
Characteristics (for DAS-2M unless otherwise noted)
Crew: 2, pilot and weapons system operator
Variants:
DAS-2A (land-based): $85 million
DAS-2M (maritime): $88 million
Wings: span: 16.42m; folded width: 12.5m; area: 58.74 m2
Fuselage: length: 24.02m (nose folded, 21.83m); height: 5.64m
Powerplant: 2 x Isselmere Motor Works ATG-9F augmented low bypass ratio three-dimensional thrust-vectoring turbofans (150 kN max. reheat (33,766 lb st), 96.4 kN max. military/dry (21,711 lb st) each)
Mass: Empty: 18,672 kg (41,167 lb); Clean take-off: 30,337 kg (66,881 lb; maximum internal fuel); Maximum take-off: 44,887 kg (98,959 lb)
Performance: Operational maximum velocity at altitude Mach 2.24; Velocity in supercruise Mach 1.32; Velocity, clean, at sea level: 1,125 km/h; Range (maximum, at altitude): 4800 km; (maximum, at low altitude): 1950 km; Service ceiling (clean): 20,000 m (65,617 ft)
Internal weapons: Royal Isselmere-Nieland Ordnance ACA.41 30mm cannon (250 rounds), ventral bay (2500 kg, for two 907 kg-class LGB or four 500 kg LGB), 2 missile bays (400 kg each, for 1 GWS.74A Kestrel or 2 GWS.65A Kite or similar)
Hardpoints/Stations: 13; centreline (400 kg), 2 aft fuselage (400 kg), 2 over-wing-root stations for conformal fuel/sensor pods, 4 outboard of wing-fold (575 kg inner, 400 kg outer), 4 inboard of wing-fold (3000 kg).
Payload: maximum: 14 550 kg (32,077 lb)
Fuel fraction: 0.36 (10 800 kg maximum; usually 8200 kg)
Thrust loading: maximum: 1.008 (clean) – 0.681 (max. load); military: 0.648 (clean) – 0.438 (max. load)
Wing loading: 516.46 kg/m2 clean take-off; 764.16 kg/m2 maximum take-off
Electronics suite
Computers: AEQ.11 environmental awareness module (EAM); AEL.15 fuel and stores management computers (3); AEP.15 flight control computers (4); AEQ.15b engine control and monitoring units (4); AEL.14 ground crew accessible module (GCAM); AEQ.242 threat management system
Computer systems: AEI.8 operating system
Displays: AVL.16 damage control; AVL.17 sensor management (WSO); AVQ.57 threat management; AVQ.58 threat management (WSO); AVQ.62 HNS; AVQ.64 fuel and engine; AVQ.65 HSD; AVQ.66 MFHDD (3); AVQ.67 MFHDD (WSO); AVQ.68 HUD (pilot); AVQ.71 HMDS
Radars: ARU.235 Loki AESA radar (fore); ARQ.284 PESA radar (aft)
Optronics: AAS.233 IRST (fore); APQ.240 forward optronic array (AJQ.229 LDRF, AVS.230 CCD); AAS.243 IR (aft)
Navigation: ARN.208 millimetric Doppler altimeter; AWN.225 UHF/TACAN; AMN.252 HNS (AJN.249 LINS and AUN.250 GPS); AWN.253 ILS aerial; AEN.256 TERPROM; ASP.263 autopilot; APN.264 MWLS
Communications: CSZ.17Ab multifunction information distribution system (MIDS); AUZ.223 satellite communications system; ASP.259 secure drone control datalink; AWZ.291 HF aerial; AWZ.292 VHF antenna; AWQ.293 ADF aerial; AWZ.301 UHF aerials (2); AWZ.302 L-band aerial; AWZ.303 S-band aerials (2)
Electronic countermeasures/Electronic support measures:
Assessment: AUX.254 combined interrogator transponder (CIT); AMX.255 Glower target recognition system (TRS)
Warning: ALR.217 Sif RWR; ALR.218 LWR; AAR.219 missile plume detectors; ALR.227 launch warning indicators
Countermeasures: ALE.209 countermeasures ejectors (6 x 32-cell); ALQ.212 Cuckoo towed deception jammers (2 x 3-cell); ALQ.228 self-protection jammer; ALI.261 integrated countermeasures system (ICMS)
Missions
Strike
3 x ALQ.220 Flamingo autonomous aerial decoys
13,800 kg armaments
* = The image from the AAS.233 forwarded to the HMDS covers only the scanning arc of the IRST. Outside of that arc, imagery from the NVE takes precedence.
** = Please note that these improved chaff and flare canisters will not protect this aircraft against every missile fired at it, just give it a slightly better than usual chance to evade destruction.
[Based on Blackburn’s Buccaneer S.2, Republic’s F-105 Thunderchief, and the General Dynamics F-111F]
DAS-4 Swordfish interdiction strike aircraft
Introduction
Like the DAS-3 Sea Fury, the DAS-4 Swordfish began with an official request for proposals from the Royal Isselmere-Nieland Navy’s Fleet Air Arm (FAA). Naval Aircraft Requirement, Number 29 (NAR-29) specified an aircraft that could perform low level attack missions at either supersonic or high trans-sonic speed at ranges in excess of 800 nm (about 1500 km) carrying its main strike armament within an internal weapons bay and equipped with at least two short range self-protection missiles and with a measure of stealth.
Though there was a host of aircraft suitably conforming to some of those specifications, in particular Dat’ Pizdy Corporation’s F-225A Kestril, Avalon Aerospace Corporation’s SZ-1 Vulture and SZ-70 Valkyrie, and Praetonia’s L-82 Hussar, none entirely fit the NAR-29 requirements. The General Dynamics F-111, though with characteristics similar to those of the NAR-29, failed in terms of engine reliability and response time and had an exceptionally large radar cross-section (RCS). The electronics suite of the F-111 was also woefully obsolete. Lockheed Martin’s FB-22 fulfilled most of the NAR-29 specifications, but not that for low altitude flying: the large wing had too great a gust response.
Detmerian Aerospace Dynamics’s design, the DAS-4, did not have the speed of the Valkyrie or the Hussar or such advanced features as pulse detonation gas turbine engines or electro-thermal chemical (ETC) cannons, but it met the range and reliability requirements established by the FAA and the foreign aircraft were not as able to fly comfortably at low level. Consequently, the FAA requested that Detmerian Aerospace produce six working prototypes – the Harridan DSP.1 one-sixth scale uncrewed strike aircraft prototype, the full-scale crewed Indigenous Design Prototype, Number 31 (IDP-31), as well as four of the finalised NAR-29 prototypes.
Development
With the success of the Harridan DSP.1 and the crewed IDP-31, the NAR-29 prototypes advanced to the airframe, engine, electronics, and weapons testing phases. The first of the development aircraft, DA1, was powered by the DAS-2’s ATG-8F engines and was modestly underpowered. Still, it managed to break the sound barrier on its first flight and showed the general suitability of the DAS-4 airframe. The mission adaptable wing fitted with spoilers, full-span leading edge slats, and low-speed flaps was shown to generate sufficient lift to reduce the landing speed to an acceptable 130 knots.
DA2, with two of Isselmere Motor Works Aeronautical Division’s ATG-9F augmented low bypass ratio three-dimensional thrust vectoring twin-shaft turbofans installed, gave the NAR-29 swift engine response and more than enough power to propel the Swordfish at well over twice the speed of sound – DA2 achieved Mach 2.52 in its sixth flight. This speed was, of course, in clean condition and without the complete electronics suite of the production aircraft.
To save funds during one of the UKIN’s economic recessions, the FAA was forced to do away with DA4 and conducted both electronics and weapons testing on DA3. Electronics testing on the sensors, electronics countermeasures, and electronic support measures passed without revealing significant interference or electronic noise problems. Weapons testing indicated initial problems with the release mechanism in the internal weapons bay when operating at maximum speed, which was corrected in a subsequent software upgrade: the bay doors failed to close owing to a conflict between the fire control computer and the signature self-detection system. Once that conflict had been resolved, the DAS-4 passed into the production phase.
Construction
Airframe
The Swordfish had to be lightweight in order to ensure rapid acceleration from the ATG-9F, strong enough to transport a massive payload over a long distance, and sturdy to withstand the stresses of high speed low level flight. Modern materials science, miniaturisation, and clever engineering combined to craft the DAS-4.
In terms of materials, forty percent of the Swordfish’s weight comes from composites, thirty-eight percent from titanium alloys, ten percent from high temperature aluminium alloys, and the final twelve percent from high quality steels with low reflective indices. The composites serve several functions. A sandwich of composite honeycomb and fabric form the wings and much of the skin of the fuselage, the wings stiffened by composite spars interspersed with spars of high strength titanium alloys used primarily for the wing hardpoints. A thin layer of Hauberk composite-ballistic ceramic armour providing additional protection to the self-sealing tanks adds strength to the wings as well. Much of the composites are radar absorbent materials (RAM) that reduce the DAS-4’s large physical cross-section to a very modest RCS.
Titanium alloys are utilised in areas subject to high physical and thermal stress such as the wing folds and roots, the engine bays and within the engines themselves, and a thin layer protecting the pilots and certain key components. Aluminium alloys with improved thermal resistance are used in the remainder of the Swordfish’s skin and support structures within the aircraft itself.
Flight control is entirely digital. Like most modern combat aircraft, the DAS-4 control surfaces and systems are managed by four flight control computers that receive and transmit commands by light signals through fibre-optic cables, known commonly as fly-by-wire. Electronic commands to the control surfaces are received by the high pressure hydraulic system fed by three distributed reservoirs enabling the aircraft to react almost instantaneously to aircrew and computer input.
Although the high top speed of the Swordfish requires the use of variable incidence intakes, the reflections potentially caused by those protuberances has been kept to a minimum. The engines are hidden deep within the fuselage minimising the infra-red signature of the aircraft and vents to the final stages of the exhaust on the upper fuselage of the aircraft may be opened to further minimise emissions. Baffles further serve to mask possible radar reflections from the fan and compressor blades.
Future designs may take advantage of research conducted on new fixed intakes to minimise both the DAS-4’s radar signature and weight.
Airfoils
The Swordfish has a small wing with a small chord for an aircraft of its size. This wing gives very low gust response – that is, the DAS-4 is not as susceptible to low altitude turbulence – making low level flight far more comfortable for the aircrew than in multirole fighters whilst prolonging the airframe’s lifetime. The small wing in no way diminishes the Swordfish’s low altitude manoeuvrability. Quite the reverse, as the fly-by-wire command-to-control surface interface and direct voice input (DVI) with hands-on-throttle-and-stick (HOTAS) man-machine interface (MMI) as well as a design that is naturally unstable in subsonic flight and with superb lift-generation devices on the wings themselves make the aircraft an extremely agile and deadly low level performer.
The wings are fixed, unlike many modern strike aircraft designs. Though fuel efficiency and manoeuvrability in all flight regimes may have been sacrificed, so has the weight penalty incurred by the variable sweep mechanism. To compensate for these purported deficiencies in a fixed wing design, the wings are stronger.
Like the DAS-2, the DAS-4 has twin canted tail surfaces to maximise supersonic stability and to reduce the chance of radar return reflections and two slab all-moving tailerons or stabilisers. The tails themselves host an array of aerials for electromagnetic signals receivers and transmitters for the ALI.261 integrated countermeasures system (ICMS).
The wings and vertical tail surfaces both support self-sealing fuel tanks allowing the Swordfish to carry an incredible quantity of fuel to conduct long range operations deep into enemy territory. Indeed, fuel may comprise to thirty-six percent (10800 kg) of the DAS-4’s clean take-off weight, though usually the Swordfish takes off with 8200 kg.
Powerplant
The Swordfish’s engines are 150 kN (96.4 kN dry thrust) IMW ATG-9F augmented low bypass ratio three-dimensional thrust-vectoring turbofans that permit the aircraft to fly at Mach 2.24 or to supercruise at Mach 1.32 (clean and at altitude in both conditions). The engines are necessarily separated by a short distance in order to accommodate the fuselage weapons bay, granting some protection against both engines being disabled by a single blow whilst the ATG-9F’s thrust vectoring can minimise the difficulties of controlling the aircraft on a single engine, which can be aggravated by widely spaced engines.
The ATG-9F, like the ATG-8F, is a modular design permitting rapid exchange of damaged components rather than of entire engines. The use of powder metallurgy – which facilitates the manufacturing of single crystal structures that are more resistant to thermal stress fractures – and of blended blade-disc (blisk) fans offer exceptional weight savings and give the engine a thrust-to-weight ratio of 1:9.34.
The thrust-vectoring mechanism is that used on the ATG-8F, with a modified universal joint to direct engine thrust up to thirty degrees off the engine’s axis not simply up and down, but through a three-hundred-and-sixty degree arc, offering superb handling capabilities and the precision release of iron bombs.
Each of the ATG-9F turbofans are controlled and monitored by two AEQ.15b computers giving the pilot full-authority digital engine control (FADEC). Engine performance from each is closely monitored and recorded to prolong engine life and to ensure maximum fuel efficiency.
Electronics
General automated systems
As noted above, the Swordfish operates in accordance with pilot and computer inputs to maintain artificial stability in subsonic flight and quick reactions in all flight regimes. A quadruplex flight control system of AEP.15 computers manages the control surfaces to give the DAS-4 its surprising agility along with the four AEQ.15b computers that administer the engines. To these eight computers are a further three for fuel and stores management (AEL.15), two for the aircrew environmental control system (AEQ.11) that distributes aircrew inputs to the appropriate systems, and one for the ground crew to perform tests and evaluation of the DAS-4’s many systems. A final pair of computers – AEQ.242 threat management systems (TMS) – serve as the Swordfish’s integrated fire control and defensive systems management. All computers use dual-core processors that are capable of in-flight recovery in case of corrupted software and are monitored by built-in test and evaluation (BITE) equipment. The computers use an open architecture operating system that permits rapid in-flight updating of mission information and swift upgrading of systems and functions in the field.
The safeguards provided by redundant computers and systems monitoring are buttressed by another hardware advantage. All of the computers use gallium arsenide chips, which are more resistant to electromagnetic pulses (EMP) that silicon-based chips. Mission critical systems such as the four flight control computers are further hardened against EMP so that the Swordfish can effectively perform free-fall nuclear bombing missions if necessary.
Sensors and related systems
The DAS-4 is bristling with sensors and electronic support measures in order to perform low-level attack missions at high speed both day and night in all weathers.
First and foremost among these systems is the ARU.235 Loki multifunction radar. The Loki is a low probability of intercept active electronically scanning array (AESA-LPI) optimised for low-level operations. With over 2000 transceiver modules arranged into sub-arrays the ARU.235 permits the Swordfish to speed along at tree-top level whilst using ground mapping radar (GMR) with moving target indication (MTI) and terrain following radar (TFR) scans to successfully avoid obstacles and to navigate using terrain reference points. GMR with MTI along with synthetic aperture radar (SAR) technology allows the DAS-4 to detect surface targets, picking out even moving targets from ground clutter, including those hidden by obstacles. The low power of each transceiver module makes the ARU.235 very difficult to detect whilst being incredibly capable.
Despite the ARU.235’s main role as a surface attack system, it can make an enemy pilot’s life a misery as well. The Loki can simultaneously detect and track surface and air targets, allowing the Swordfish to prosecute foes in the air as well as on the ground. Inverse synthetic aperture radar (ISAR) technology can cut through stealth technology and electronic countermeasures, using a target’s own movement to reveal it for termination.
Enemy emitters, rather than giving the Swordfish’s foes an advantage, simply permit the DAS-4 to either avoid or attack them. The ARU.235, with sub-arrays in either operating in a active-passive mode or purely passive reception role, can detect and classify specific emitters at much greater than their detection range. Using that information, the Swordfish can respond with anti-radar or air-to-air missiles as required. Alternatively, the DAS-4 can simply sneak its way under and around those enemy radars to perform surprise strikes against heavily defended targets.
The Loki can instead use the electronic intelligence it receives to respond with electronic countermeasures (ECM) by jamming those emitters. The ARU.235 can serve as a noise or deception jammer (using range gate stealing or active cancellation) over its wide range of bandwidths (X-band and the higher end of L-band and the lower bandwidth of the K-bands).
In addition to the ARU.235, the Swordfish is equipped with a rear passive electronically scanned array (PESA), forward and rear sector optronics, and the helmet-mounted display/sight (HMDS) system.
The AVQ.71 HMDS in conjunction with direct voice input (DVI) makes the pilot-weapons system operator (WSO) team in a Swordfish an exceptionally deadly pair. The HMDS conveys information collated by the AEQ.242 and the AEQ.11 computers to the aircrew in simple to understand symbology permitting rapid response to threats and targets of opportunity without having to divert their attention to the HUD or other displays. The AVQ.71 is fitted with night vision equipment (NVE) giving the aircrew full visibility during night missions.
Target cueing using the AVQ.71 is achieved either through DVI or by depressing a button on the control relay mechanisms such as the control stick and throttle or the WSO’s joysticks. The pilot or WSO maintains the object of interest – which need not be an object presently detected by either the sensors or the ESM – in sight until it is noted by a targeting caret. Noting of previously unidentified objects can occur within milliseconds, depending on the object in question.
The DVI system at present has a vocabulary of approximately 500 words attuned to the speech patterns of the aircrew. This working dictionary is usually developed over several training missions and is stored in secure, transferable data transfer devices.
Size restrictions necessitated the use of a PESA rather than an AESA in the aft quarter, but the ARQ.284 can still perform most of the functions of a shorter ranged version of the ARU.235. The X-band PESA usually serves as a passive receiver for enemy interceptor radars though it may be used to provide a short sharp burst of radio waves to overwhelm the seeker heads of active radar homing missiles. Doing so does severely diminish the service life of the unit and may cause damage to friendly radars, but line replaceable units (LRU) and shop replaceable items (SRI) are far easier to exchange than aircrew. The range of the ARQ.284 against small fighter-sized targets is approximately 60 km in active tracking mode.
The Swordfish sports a wide assortment of optronics as well. Its forward optronics array consists of an AAS.233 infra-red search-and-track (IRST) turret and an APQ.240 multifunction detection and ranging array. The IRST can passively acquire and track air and surface targets or to assist in low-level navigation day or night in all weather conditions. In low-light and nighttime conditions, the AAS.233 may feed its view to the aircrew’s HMDS or other displays.*
Should the AAS.233 be rendered inoperable, a GWS.65Aa Kite infra-red missile seeker head may be used as an IRST.
The APQ.240 consists of an AJS.229 laser designator/range-finder (LDRF) and an AVS.230 low-light capable charge-coupled device (CCD). Unlike the APQ.240 on the Spectre, that on the Swordfish is chin-mounted to identify and illuminate ground targets. Imagery from the APQ.240 may likewise be forwarded to the HMDS or other displays.
In the rear sector, the Swordfish has tail-mounted aerials for the AAS.243 infra-red (IR) search arrays to detect incoming missiles and approaching fighters as well as two further low-light level capable CCDs used primarily for battle damage assessment (BDA). The AAS.243 has entered a new age of usefulness with the introduction of the new rear-firing missile hardpoints: in air exercises, a number of fighter pilots have been “destroyed” by supposedly vulnerable Swordfish.
Threat management
To attack the most heavily defended targets and protect itself against foes determined to remove it from the sky, the Swordfish has been given a threat management suite capable to detecting and defeating a broad variety of enemy systems.
The basis of the AEQ.242 threat management system (TMS) are two computers that compile the immense volume of data coming from the active and passive arrays detailed above, such as the ARU.235 and the AAS.243, as well as the receiver systems, notably the ALR.217 radar warning receiver (RWR) and ALR.218 laser warning receiver (LWR) arrays that detect and home on emitters, and the missile approach warning system (MAWS), comprising of the AAR.219 missile plume detector and the ALR.227 launch warning indicator arrays that monitor radiated radio and infra-red energy coming from emitters and launchers as well as the missiles themselves.
Data to the AEQ.242 comes from the DAS-4’s identification and classification systems as well. The AUX.254 combined interrogator transponder (CIT) is the Swordfish’s identification friend or foe (IFF) aerial. The CIT set uses beam steering not only to identify whether a bogey or land unit is friendly or hostile, but may provide additional targeting data such as altitude and speed as well. The AMX.255 target recognition system (TRS) vets both returned queries from the CIT or by other IFF units as well as from the DAS-4’s radar, infra-red, and optical sensors and emission receivers, cross-referencing that data with information within its threat library. New threats may be catalogued in-flight by the AMX.255 and passed along to fellow flight members using a secure datalink (covered below).
With this information, the AEQ.242 presents the aircrew with a concise but thorough visual description of known threats through the HMDS as well as the HUD and head-down displays as desired by the aircrew. This allows the Swordfish to navigate around the worst threats as well the means by which to foil the others.
Should avoidance not be possible, the Swordfish has an elaborate countermeasures suite, starting with the ALQ.228 self-protection jammer (SPJ). The ALQ.228 is capable of receiving a broad spectrum of radio bandwidths and of countering the most commonly used surface-to-air missile (SAM) control and fighter radars and of noise and deception jamming on the S, L, and X-bands – an expanded capability model is currently in service with the RINN and the JGN – as well as a limited capacity to jam communications.
If the ALQ.228 SPJ and the ARU.235 and ARQ.284 radars fail to dissuade an enemy attack, the Swordfish can respond with an assortment of expendable countermeasure decoys. Though not an integral part of the DAS-4, the ALQ.220 Flamingo autonomous aerial decoy is certainly the cornerstone of the aircraft’s defence. Equipped with a modest laser ring gyro inertial navigation system (LINS), a secure datalink relay with the launching aircraft, a radar reflector and a small set of short range warning receivers of its own, the 250 kg Flamingo adopts the flight characteristics of the launching aircraft. The Flamingos may be used to feint in an alternative direction or to fill the sky with a host of alternative, more seductive radar targets for active radar guiding missiles and air defence radars. The Swordfish usually carries three ALQ.220 during strike missions. Flamingos with improved infra-red deception capability will be entering service in the near future.
Next in the DAS-4’s arsenal of deception is the ALE.212 towed deception decoy (TDD) unit. The Swordfish sports two three-cell ALE.212 units on its wingtips. When released, the ALE.212 decoys trail one hundred metres (100 m) behind the DAS-4 on thermally insulated fibre-optic cables capable of withstanding +6/-3 g manoeuvres. Connected to the ALI.261 integrated countermeasures system (ICMS) by the fibre-optic cable, the decoy may be configured in flight to counter specific incoming threats, forcing SAM and air-to-air missiles to detonate prematurely. There are two models of the ALE.212 decoys: the ALE.212a radar decoy and the ALE.212b IR decoy. The ALE.212b has just entered RINN and RINAF service and will soon be appearing in JGN aircraft. It emits pulses of IR radiation invisible to the naked eye to fool even the more discerning IR-seeking missiles.
When even the ALE.212 fails, the Swordfish still has six 32-cell ALE.209 expendable aerial countermeasures ejectors (EACME) for chaff canisters and flares. Improved radar and IR decoys – including non-incandescent ‘flares’ – capable of fooling even modern highly sensitive missile seeker heads may be used as well and are currently in service with the UKIN-DF.**
The ALI.261 ICMS manages all of these varied countermeasure systems. The ICMS may be configured to operate entirely autonomously of aircrew-input, in conjunction with pilot or WSO commands, or strictly in accordance with aircrew input. Effectively a sub-system of the AEQ.242, the software of the two systems and that of the AMX.255 – another AEQ.242 sub-system – has been rigorously tested to avoid command conflict. The aircrew is thus left only with an incredibly clear picture of their flying environment.
Communications
The communications equipment on the Swordfish is diverse, covering the HF to UHF bands as well as the S- and L-bands. All of the radios aboard the DAS-4 are designed to operate over secure channels, although for intercepts of civil aircraft, open channels may be used. There is a secure satellite communications aerial for the embedded global positioning satellite (GPS) system and to maintain contact with higher echelons as well.
Yet the most common means of communication between flight mates and uncrewed aerial vehicles (UAV) is through multi-function information distribution systems (MIDS) or datalinks. The Swordfish is equipped with two datalinks. The CSZ.17Ab general purpose datalink allows the DAS-4 to communicate with fellow flight members or with similarly equipped aircraft. The ASP.259 provides tactical control to UAV, which the WSO or the pilot may use to reconnoitre targets or to provide a diversion or additional support. With both systems, the Swordfish can coordinate devastating attacks and mutual support against the enemy, overwhelming him or her with aerial targets and overwhelming firepower.
Navigation
The ARU.235 Loki is a multipurpose low probability of intercept active electronic scanning array (AESA-LPI) optimised for low-level operation and attack, offering Swordfish crews superlative information for nape-of-the-earth (NOE) flight in all conditions, day or night. The ARU.235’s ground mapping and terrain following functions (GMR and TFR) use synthetic aperture radar (SAR) technology to identify targets that might otherwise be hidden by obstructions. Along with the AMN.252 hybrid navigation system (HNS) – comprising of an AJN.249 laser ring gyro inertial navigation system (LINS) and an AUN.250 embedded GPS system – the ARU.235 provides the Swordfish crew with terrain profiling and matching (TERPROM) capability managed by the AEN.256 computer, allowing the aircraft to fly accurately, safely, and with the minimum of electronic emissions over dangerous terrain.
With the ARU.235’s ability to act as a passive receiver for enemy radars allow the Swordfish to keep below enemy air defences while not endangering the crew. The TFR system delivers information immediately to the head-up display and the helmet mounted display/sight (HMDS) system permitting the pilot to retain perfect situational awareness. The TFR may be used to automatically correct the aircraft’s flight path to counter obstacles or enemy air defences. The Loki uses synthetic aperture radar technology to assign optimal attack vectors, ingress and egress points, as well as to define otherwise unseen targets.
As well as these systems, the Swordfish sports aerials for an LPI millimetric wavelength Doppler radar altimeter, tactical air navigation (TACAN), and an instrument landing system (ILS). But devices are not the end to the DAS-4’s navigational avionics.
The Swordfish is equipped with a superlative autopilot and microwave landing system (MWLS) that allows for complete automatic control of flight operations from wheels up to touchdown. The ASP.263 autopilot in automatic gun aiming mode combines data from the ARU.235 and the front sector optronics (AAS.233 and the APQ.240) with that from the AEP.15 flight control computers to give the DAS-4 a one-shot kill capability with the ACA.41 automatic cannon.
Cockpit
The cockpit stations for the pilot and the WSO are dominated by polychromatic active matrix liquid crystal displays (AMLCD). The so-called glass cockpits present flight data, threat information, and targeting solutions to the aircrew using easy to understand symbols, minimising the need to hunt for this or that steam gauge-style instrument. The pilot also has use a large, wide-angle HUD that may be disengaged in preference to the HMDS. The WSO’s station has been optimised for sensor and weapons control with additional mechanisms to facilitate UAV control.
The arrangement of the displays was arrived at after much ergonomic testing for ease of use and interpretation whilst in the midst of aerial combat.
Stores
The aircraft has an internal weapons bay has been stressed for 2500 kg with room enough for two 1000 kg precision guided munitions (PGM) such as laser guided bombs (LGB). Two smaller internal missile bays are located on the side of each air intake. Each missile bay may carry either one medium-sized beyond visual range missile such as the AIM-120C AMRAAM or the GWS.74A Kestrel or two intermediate-to-short range missiles such as the AIM-9X Sidewinder, the ASRAAM, the IRIS-T, or the GWS.65A Kite. The Swordfish sports an ACA.41 30 x 173mm automatic cannon with 250 rounds capable of accurately striking targets at almost two kilometres (1.83 km to be precise) that is still quite deadly against some armoured vehicles.
The fuselage bears three external hardpoints as well. After the recent air battles in Inkana, two further recessed hardpoints for rear-firing intermediate-range missiles were added to provide the aircraft with rare off-boresight killing capability. The recesses, designed for GWS.65A missiles, but which may be altered to conform to the short-to-intermediate range missiles used by the purchasing nation, generate very little additional drag when the missile is in place. A piston safely propels the missile from the aircraft before the motor ignites. The final fuselage hardpoint is aft of the weapons bay and fore of the arrestor hook. This centreline hardpoint primarily serves to launch ALQ.220 Flamingo autonomous deception decoys, although it may be used to carry one ALQ.222 Finch electronic countermeasures pod.
Atop each wing-root are connections for two large (2700-litre) conformal fuel tanks (CFT) or additional avionics. The CFT and the internal weapons bays permit the Swordfish to prosecute targets at extreme range with minimal drag or radar cross-section (RCS) penalties. The CFT have been constructed to withstand the entire range of the DAS-4’s flight envelope whilst the internal weapons bay can maintain its integrity to over +7/-3 gravities (g) sustained.
Each wing has four hardpoints. The two innermost hardpoints on each wing are each stressed to carry 3000 kg in flight regimes of greater than +6/-3 g sustained. The outer two hardpoints on each wing have been stressed for 575 kg (inner) and 400 kg (outermost). The outermost pylon has been wired for the launching of the ALQ.220 Flamingo decoy.
In terms of weapons functionality, the Swordfish can easily carry most aerial weapons systems currently produced by Lyme and Martens Industries – with the sole exception of the massive GWS.58A Hurricane long-range surface attack missile -- and may easily be configured to fire a very wide assortment of other devices.
Characteristics (for DAS-2M unless otherwise noted)
Crew: 2, pilot and weapons system operator
Variants:
DAS-2A (land-based): $85 million
DAS-2M (maritime): $88 million
Wings: span: 16.42m; folded width: 12.5m; area: 58.74 m2
Fuselage: length: 24.02m (nose folded, 21.83m); height: 5.64m
Powerplant: 2 x Isselmere Motor Works ATG-9F augmented low bypass ratio three-dimensional thrust-vectoring turbofans (150 kN max. reheat (33,766 lb st), 96.4 kN max. military/dry (21,711 lb st) each)
Mass: Empty: 18,672 kg (41,167 lb); Clean take-off: 30,337 kg (66,881 lb; maximum internal fuel); Maximum take-off: 44,887 kg (98,959 lb)
Performance: Operational maximum velocity at altitude Mach 2.24; Velocity in supercruise Mach 1.32; Velocity, clean, at sea level: 1,125 km/h; Range (maximum, at altitude): 4800 km; (maximum, at low altitude): 1950 km; Service ceiling (clean): 20,000 m (65,617 ft)
Internal weapons: Royal Isselmere-Nieland Ordnance ACA.41 30mm cannon (250 rounds), ventral bay (2500 kg, for two 907 kg-class LGB or four 500 kg LGB), 2 missile bays (400 kg each, for 1 GWS.74A Kestrel or 2 GWS.65A Kite or similar)
Hardpoints/Stations: 13; centreline (400 kg), 2 aft fuselage (400 kg), 2 over-wing-root stations for conformal fuel/sensor pods, 4 outboard of wing-fold (575 kg inner, 400 kg outer), 4 inboard of wing-fold (3000 kg).
Payload: maximum: 14 550 kg (32,077 lb)
Fuel fraction: 0.36 (10 800 kg maximum; usually 8200 kg)
Thrust loading: maximum: 1.008 (clean) – 0.681 (max. load); military: 0.648 (clean) – 0.438 (max. load)
Wing loading: 516.46 kg/m2 clean take-off; 764.16 kg/m2 maximum take-off
Electronics suite
Computers: AEQ.11 environmental awareness module (EAM); AEL.15 fuel and stores management computers (3); AEP.15 flight control computers (4); AEQ.15b engine control and monitoring units (4); AEL.14 ground crew accessible module (GCAM); AEQ.242 threat management system
Computer systems: AEI.8 operating system
Displays: AVL.16 damage control; AVL.17 sensor management (WSO); AVQ.57 threat management; AVQ.58 threat management (WSO); AVQ.62 HNS; AVQ.64 fuel and engine; AVQ.65 HSD; AVQ.66 MFHDD (3); AVQ.67 MFHDD (WSO); AVQ.68 HUD (pilot); AVQ.71 HMDS
Radars: ARU.235 Loki AESA radar (fore); ARQ.284 PESA radar (aft)
Optronics: AAS.233 IRST (fore); APQ.240 forward optronic array (AJQ.229 LDRF, AVS.230 CCD); AAS.243 IR (aft)
Navigation: ARN.208 millimetric Doppler altimeter; AWN.225 UHF/TACAN; AMN.252 HNS (AJN.249 LINS and AUN.250 GPS); AWN.253 ILS aerial; AEN.256 TERPROM; ASP.263 autopilot; APN.264 MWLS
Communications: CSZ.17Ab multifunction information distribution system (MIDS); AUZ.223 satellite communications system; ASP.259 secure drone control datalink; AWZ.291 HF aerial; AWZ.292 VHF antenna; AWQ.293 ADF aerial; AWZ.301 UHF aerials (2); AWZ.302 L-band aerial; AWZ.303 S-band aerials (2)
Electronic countermeasures/Electronic support measures:
Assessment: AUX.254 combined interrogator transponder (CIT); AMX.255 Glower target recognition system (TRS)
Warning: ALR.217 Sif RWR; ALR.218 LWR; AAR.219 missile plume detectors; ALR.227 launch warning indicators
Countermeasures: ALE.209 countermeasures ejectors (6 x 32-cell); ALQ.212 Cuckoo towed deception jammers (2 x 3-cell); ALQ.228 self-protection jammer; ALI.261 integrated countermeasures system (ICMS)
Missions
Strike
3 x ALQ.220 Flamingo autonomous aerial decoys
13,800 kg armaments
* = The image from the AAS.233 forwarded to the HMDS covers only the scanning arc of the IRST. Outside of that arc, imagery from the NVE takes precedence.
** = Please note that these improved chaff and flare canisters will not protect this aircraft against every missile fired at it, just give it a slightly better than usual chance to evade destruction.
[Based on Blackburn’s Buccaneer S.2, Republic’s F-105 Thunderchief, and the General Dynamics F-111F]