SWR-787 Yakumo

SWR-787 Yakumo
Type	Anti-ship missile
Place of origin	Carthage
Service history
In service	2009-present
Used by	Carthage Gensokyo Republic Japan
Production history
Designer	RMA Corporation Mitsubishi Heavy Industries
Designed	2003-2009
Manufacturer	RMA Corporation Mitsubishi Heavy Industries
Unit cost	$3.5 million (FY2010)
Produced	2008-present
No. built	80,000+
Specifications
Weight	1,800 kg (4,000 lb)
Length	6.8 m (22 ft) 7.5 m (25 ft) (w/booster)
Diameter	520 mm (20 in)
Warhead	Up to 450 kg (990 lb) including Mk 102 Advanced Multi-stage Penetrator SWT-740 Super Perseid lightweight torpedo Submunition dispenser
Detonation mechanism	Active radar proximity fuse Backup impact fuse
Wingspan	4.6 m (15 ft)
Propellant	Magonid Motors TFM-300-45EX turbofan
Operational range	Up to 1,500 km (930 mi) for hi-lo flight profile
Flight ceiling	20,000 m (66,000 ft)
Flight altitude	Sea-skimming w/terminal pop-up
Speed	960 km/h (600 mph)
Guidance system	Inertial/GPS w/datalink Active radar homing + IR terminal guidance
Launch platform	Multi-platform

The SWR-787 Yakumo is a modern all-weather, over-the-horizon, anti-ship missile system developed and manufactured by the RMA Corporation and Mitsubishi Heavy Industries. Designed to be launched from standard warship vertical launch systems, it is a fire-and-forget missile with multi-mode guidance and both sea-skimming and high-altitude attack capability. Introduced in 2009, it replaced the SWR-781 Kanako in service with the navies of Carthage and the Japanese Empire.

Development

Yakumo was developed jointly by the RMA Corporation and Mitsubishi Heavy Industries to replace the older box-launched Type-65 Kanako anti-ship missile, developed in the late 1970s as a reaction to the large-scale deployment of the European Exocet missile. The Northern War of 1975 had demonstrated that despite the disparity in aircraft carrier strength between the European Federation and Carthage, proper and widespread use of anti-ship missiles posed a significant threat to surface warships.

Carthaginian and Shogunate anti-ship missile technology had fallen behind that of Europe and the Russian Empire, and the Type-65 was developed as a quick stop-gap for rapid deployment to address this shortcoming, based on initial concepts for an anti-submarine missile. Kanako entered service in 1977, shortly after the end of the Northern War after a development period of only two years. The design made heavy use of readily available components and was introduced with comparatively little testing. As a result, the Type-65 was a relatively limited-capability weapon, with a subsonic cruising speed, modest range, and relatively light warhead that made it increasingly vulnerable to point-defense systems and less effective against larger targets. Improvements to missile guidance and improved variants of the Sarkin T319 turbojet brought about substantial increases in accuracy and range, but the design remained constrained to the size limitations of the original box launchers, limiting future growth potential.

In 1997, a Memorandum of Understanding was signed between the governments of Carthage and the Japanese Empire agreeing to co-develop a new anti-ship missile, to be much more capable and lethal against modern surface combatants. Design features were taken from Russian anti-ship missiles in terms of size and capability, while compatibility with standard VLS tubes was an ultimate goal, abandoning the previous box launcher requirements. The switch to VLS launch significantly relaxed the size restraints and simplified launch arrangements for new warships going forward, including the new Flight IV Elementario-class destroyer. Instead, a new box launcher was developed for smaller ships not capable of fielding the full-size VLS required, with variants developed for air and land use. Initially scheduled for deployment in 2005, the addition of several new design goals as well as development issues pushed rollout back to 2009, when the first batch of production missiles was delivered to clients.

Operational features summary

Yakumo is an all-weather, over-the-horizon missile designed to increase engagement ranges and kill probability against modern naval combatants. Compared to the SWR-781 Kanako, Yakumo is faster, larger, and heavier, with a more advanced electronics package for improved resistance to countermeasures and increased detection range. It is capable of using independent, inertial, satellite, and datalink guidance to steer the missile toward its target before entering terminal engagement. Onboard sensors are capable of intelligently detecting and to some extent avoiding defense networks along the projected flight path. The missile is designed to cruise at a speed of 960 km/h (600 mph), an improvement over the SWR-781's cruise speed of 880 km/h (550 mph).

To improve survivability and kill probability, the SWR-787 is designed for both radar and infrared stealth to reduce the chances of detection and interception prior to terminal engagement. To maximize range, the missile may be programmed to fly most of its course at high altitude, moving to lower altitudes closer to the target to avoid premature detection. Alternatively, in environments with more numerous intervening threats without a need for maximum range, the missile may instead be programmed to fly its entire course at sea-skimming altitudes. The missile's onboard electronics can detect radar emitters and alter the missile's course to avoid these sites using sophisticated route-planning software similar to that used in stealth aircraft. Complex routes can also be programmed into the missile before launch, allowing it to avoid known threats. In the terminal phase the missile is programmed for pseudo-random maneuvers to impede engagement by gun-based CIWS.

Although a subsonic design, the SWR-787 is capable of being carried at speeds exceeding Mach 2, and may be launched at speeds of up to Mach 0.9 from a wide range of altitudes. The design uses a lifting body design for reduced drag and improved range.

Description

Seeker

The SWR-787 Yakumo uses a multi-mode seeker, combining a compact X-band radar unit and an imaging infrared sensor to defeat both IR and radar countermeasures. The X-band seeker can detect noise jamming attempts and switch to home-on-jam mode and has improved discrimination against deception jamming techniques. Combined with the onboard infrared sensor, the missile has a greatly reduced chance of seduction. During the mid-course phase, the radar seeker can operate as a passive radar receiver, with onboard software allowing the missile to intelligently detect and avoid emitting radar sources (such as SAM batteries) en route to its target.

In addition to the active terminal seekers, the SWR-787 includes a radar altimeter for sea-skimming flight and a satellite navigation receiver. In the event the navigation system is jammed or unavailable, the missile has an backup inertial navigation system to allow it to retain its course, albeit with reduced accuracy. Datalink capability allows the missile to be updated with new targets or new positions in flight and to be controlled by a platform other than the launch vehicle (such as a forward AEW&C aircraft).

Fuze

In most configurations, Yakumo missiles are equipped with a dual active radar proximity fuze and a backup impact fuze. The active fuze calculates the proper standoff distance for detonation to ensure maximum effect on target, with the impact fuze taking over if the missile has not detonated before impact. A self-destruct fuze is also included, usually set to detonate after a preset amount of time without the missile's terminal guidance mode activating but also capable of command detonation. When equipped with a Type 36 torpedo or submunition dispenser, the radar and proximity fuzes are omitted in favor of the torpedo's onboard fuze.

Warhead

The primary warhead for the SWR-787 is the Mk. 102 Advanced Multi-stage Penetrator, a 450 kg (990 lb) design incorporating a precursor shaped charge and a follow-on high-explosive fragmentation bomb. The warhead is designed to penetrate hardened targets before releasing the follow-on bomb, which is normally programmed to detonate inside the target. For anti-ship use, both munitions may be programmed to detonate simultaneously if desired.

Alternatively, the SWT-740 Super Perseid lightweight torpedo may be used instead, providing extended-range anti-submarine capability. The SWR-787 is also compatible with the Mark 45 submunition dispenser developed for the SMN-788 Sakuya, but has never operationally carried this payload. As replacement of the warhead requires depot-level facilities and cannot be accomplished while underway, warhead replacement is a rare occurrence.

Propulsion and control

The propulsion system uses a Magonid Motors TFM-300-45EX compact turbofan engine, a significant improvement over the older Sarkin T319-series turbojet used in the Type-65. The TFM-300-45EX is an improved version of the original TFM-300-45 used in the Silent Spear concept drone, tuned for greater fuel efficiency, increased thrust, and reduced infrared signature. The TFM-300 can propel the SWR-787 to its cruising speed of 960 km/h (600 mph) across a range of altitudes and is fed by an S-ducted intake to reduce radar returns.

Aerodynamic control is exercised through the missile's two wings and cruciform tail arrangement, much like a conventional cruise missile. The missile is designed for high terminal-phase agility to avoid evasive maneuvers and interception methods by the target, capable of maneuvering at up to 14 g. Attention was given during design to reduce radar cross section through use of shaping as well as limited use of radar absorbent materials in the missile body and wings.

Datalink and countermeasures

The missile's datalink capability allows it to link with other missiles as well as manned platforms to share data, improving lethality against grouped targets by reducing redundant targeting of certain enemies while others are left unengaged. The missile may also be launched against targets observed by a remote platform, allowing forward observers to provide datalink support to the missile in flight and allowing the launch platform to remain at a safe distance from the target. The primary antenna is mounted in the rear of the fuselage.

The missile uses a low-observable body casing, designed to minimize radar and infrared returns. Through both shaping as well as the use of low-return materials, the missile reduces detection range for enemy defensive systems. The multi-mode seeker reduces the effectiveness of radar and IR-based countermeasures, while the missile carries a light onboard ECM/ECCM suite designed to interfere with efforts to intercept the missile or achieve a lock while on approach.

Maintenance and support

Missiles are packaged from the factory as sealed rounds with an integrated fault-detection equipment. When held in storage, the missile can automatically report any malfunctions or failures, allowing the missile to be returned to the manufacturer for refurbishment. When removed from its storage casing for use, the missile is connected to a similar system onboard its host ship, allowing it to report faults while underway for replacement in port. Current reliability benchmarks are for 5,000 hours mean time between failures when deployed and a storage life of 10 years.

Launch platform

The SWR-787 can be stored and launched from any Mark 18 vertical launch system installed on nearly all Carthaginian and most Shogunate warships. It is also designed for submarine use either via horizontal torpedo tube launch or from submarine VLS tubes. Due to the missile's large size, however, standard 533 mm torpedo tubes cannot accommodate the missile and its launch canister. In normal surface operation, the missile is cold-launched from its tube and in submarine operation is usually released with a protective covering to shield the low-observable material from water damage.

The missile may be air-launched from all heavy strike aircraft (such as maritime patrol aircraft and strategic bombers) as well as medium aircraft including strike fighters but is too large to fit in the internal weapons bays of stealth aircraft like the RFM-202 Shaheen.

Variants and upgrades

The SWR-787 is the current production model, with 80,500 missiles delivered to date and an additional 44,500 missiles on current order. Current production contracts run through 2018, but it is expected that should upgraded models become available, production contracts would be switched to the newer version.

The SWR-787AM1 is an upgraded model currently undergoing testing. Primary differences include slightly reduced wingspan and enlarged aerodynamic control surfaces, along with a more advanced guidance system. Final testing is slated for 2016 at which point a decision will be made whether to introduce the new design.

Operators

• Carthage
  • Carthage Air Forces
  • Punic Navy
    • Mark 18 vertical launch system
• Japan
  • Imperial Navy
• Gensokyo Republic
  • Republic Aerospace Corps
  • Republic Navy

See also

Comparable missiles

• BGM-109 Tomahawk
• BrahMos
• LRASM
• P-700 Granit
• Perseus
• RATTLRS