RIM-116 Rolling Airframe Missile (RAM) Ship Self-Defence Weapon System & RIM-116C Block II Missile

by İbrahim SÜNNETÇİ Raytheon Missile Systems and the RAM-System GmbH (RAMSYS), consortium of Diehl BGT and MBDA Deutschland GmbH in Germany, are prime contractors and co-operating partners for the RAM Program. RAMSYS and Raytheon Missile Systems are continuing to deliver the latest Block II version of the RIM-116 Rolling Airframe Missile (RAM) Ship Self-Defence Weapon System. The RAM Block II is designed to pace the evolving anti-ship cruise missile threat and improve performance against complex stream raid engagement scenarios.

Date: Issue 95 - October 2019

The Rolling Airframe Missile (RAM) is a fire-and-forget Close-In Weapon System (CIWS) for ship self-Defence against Anti-Ship Missiles (ASM), helicopters, aircraft and surface targets. The RAM was designed to engage the most challenging threats and is one of the few ASM Defence systems capable of effectively coping with multiple and high-density raids, even in littoral scenarios. The RAM Mk31 Guided Missile Weapon System consists of a rotatable and elevating launcher (Mk49 GMLS) with 21 cells for the storage of the highly precise RIM-116 Block I and Block II missiles and is integrated with the Combat Management System (CMS) of the naval platform. The RAM’s specific self-Defence capabilities include fast reaction time, multiple-threat engagement (more than 4 threats), high maneuverability and high lethality.

Upon target acquisition and assignment by the fire control system of the ship being attacked, based on target data delivered by the onboard sensor equipment, the entire target engagement process runs semi or fully automatically. This means, from this point on the sensor, fire control and computer capacities of the ship firing the missile are free for other tasks. In a typical engagement, radar and passive tracks of a target are correlated by the Combat Direction System, (CDS), which designates the target to the weapon system. A launcher is assigned to the target and subsequently a RAM round is fired. After launch, the RAM Missile detects radar emissions from the target to make midcourse guidance corrections. As the target is approached, guidance is switched to infrared homing for final corrections. Detonation of the warhead within lethal range of the target is initiated by a signal from the optical fuze (Active Optical Target Detector/AOTD). A contact fuze located in the control section provides an alternate method of fuzing by detonating the warhead upon target impact. The MK 20 Mod 2 AOTD is a narrow-beam, active optical proximity fuze system which has been adapted from the AIM-9 Sidewinder program to improve performance against anti-ship cruise missiles at extremely low altitudes over water. The AOTD transmits pulsed IR energy through the four forward windows and an IR detector/receiver receives the reflected energy. Since the missile is rolling through its length axis, via the AOTD’s windows/optics a 3D picture of the outer atmosphere is obtained and if the missile could not perform a direct hit to the target and have a passing target the AOTD transmits a signal towards the warhead and then the warhead explodes so even if it’s not a direct hit, a tactical hit is achieved.  

Normally each aircraft target, which is a relatively straight target, is engaged by one missile but against anti-ship missiles – which needs about 30-40 seconds to hit the vessel – some navies, in accordance with their operational and military doctrines, prefer to fire 2 missiles against 1 target. In case the anti-ship missile is hit by the first missile, the second missile, that knows there is a first missile, continues its flight since there’s no target anymore and destroyed after reaching its maximum range, there’s no self-destruction mechanism on RAM Missile.

The RIM-116 RAM Missile incorporates passive radio frequency (RF) and Infrared (IR) sensors (dual-mode guidance capability) allowing track and guidance against both radiating and non-radiating threats. The supersonic 5-inch RIM-116 RAM Missile was originally developed using existing AIM-9 Sidewinder components along with a STINGER infrared frequency seeker. The RAM Missile utilizes the Sidewinder fuze (AOTD upgraded for RAM), warhead, and solid propellant rocket motor. The guidance section consists of a passive RF Receiver and two RF Antennas (interferometer antennas) along with a STINGER IR Seeker. The control section consists of an electromechanical system that directs two variable control wings (canards) and two fixed wings. The RAM Missile is enclosed in a canister that also serves as a launching tube.

The RAM incorporates a statically controlled rolling airframe during flight with full maneuverability obtained by a single plane of control surfaces and a closed loop autopilot. A body fixed RF interferometer incorporates only two forward facing antennas, obtaining two planes of target information over the roll cycle. The IR sensor is mounted to a free gyro seeker, which also serves as the inertial reference for body decoupling. The RAM Block I IR sensor incorporates 80-element linear array, which uses the free gyro spin and missile roll to provide an accurate inertially referenced IR image. This allows real time acquisition and discrimination of targets in a variety of maritime backgrounds.

The RAM has been in production since 1989 and is operational on over 220 Launchers on more than 165 ships, ranging from 500-ton Fast Attack Craft to 95,000-ton aircraft carriers in 11 countries worldwide. In total RAMSYS and Raytheon Missile Systems have produced more than 5,500 missiles including RIM-116A (Block 0), RIM-116B (Block I), RIM-116B-1 (Block IA HAS [Helicopter, Aircraft, Surface]) and RIM-116C (Block II). In more than 590 flight tests and operational firings performed against current and looming advanced anti-ship threats the RAM has proven first-shot kills on target in self-Defence scenarios such as lowest level sea-skimming, diving and highly maneuvering profiles in single, stream and wave attacks - achieving a kill-performance above 95%.

Between 2007 and 2012, the RIM-116C RAM Block II upgrade was developed. The RAM Block II was delivered to the US Navy in August 2014 and the Initial Operational Capability (IOC) for the Block II Missile was achieved on 15 May 2015. On 28 March 2013, RAMSYS was awarded a procurement contract for 445 RAM Block II missiles for the German Navy. The missiles will be delivered between 2016 and 2019 and replace older Block 0 missiles, which after more than 20 years, have reached the end of their service life. As of mid 2019 roughly 600-700 RAM Block II Missiles have been delivered of which 400 for the US and rest to Germany and one other customer.

The upgrade comprises a kinematic increase in maneuverability (Enhanced Kinematics, 4 canards vs. 2 for Block 1A) to engage particularly sophisticated anti-ship missiles as well as the integration of an Evolved Radio Frequency Receiver (passive) including signal for the highly accurate evaluation of target data and Upgraded Control and Autopilot System (digital autopilot). These performance characteristics ensure excellent protection against current and future conventional and asymmetrical threats. In particular, they also guarantee protection against hypersonic anti-ship missiles performing maneuvers during final approach and low-signature threats. The Block II upgrade significantly expands the missile’s effective engagement envelope by introducing a larger dual-thrust rocket motor and independent four-canard control actuator system to increase effective range and deliver a three-fold improvement in maneuverability. One of the design criteria for the Block II Missile was the new parameters. Block II is an answer for supersonic missile threats. According to Raytheon Missile Systems the RAM Block II Missiles are 2.5 times more maneuverable and have 1.5 times the effective intercept range.

The RAM Block II Missile is a little bit longer and larger than the Block I version but there is enough space in the Mk49 Guided Missile Launching System (GMLS, Launcher). Even the Block II Missile is a little bit heavier, roughly 20 kg, than the Block I versions the total weight of 21-Cell Mk49 Mod 3 Launcher is about a half a ton heavier then when it was equipped with RAM Block II Missiles but there’s no update required for the trains and for the platform due to the increase in weight. Since from the outer dimension the RAM Block II canister is still the same with the RAM Block I it can be directly put it into the MK49 GMLS. For full integration a software update is required in the below deck equipment and in the hardware components. In this context the Combat Management System (CMS) of the ship that normally thinks there is a RAM Block I Missile in the canister/Launcher with previously identified parameters, needs new software for Block II Missile to let it recognize that there is a Block II Missile inside the canister. For the CDS (Combat Direction System, which designates the target to the weapon system)a software update is obviously requested because of the physical and electronical parameters, and the parameters regarding the RAM Block II’s sensor suite, which is different and has higher performance, the CMS has to recognize how to interact with that – that is the main problem for the integration of the RAM Block II on a vessel with the RAM Mk31 Guided Missile Weapon System. But it is not a significant endeavor, it is relatively quite easy to integrate.

Stabilized by rolling through the air, the RIM-116B (Block I) and RIM-116B-1 (Block IA HAS [Helicopter, Aircraft, Surface]) Missiles have a length of 2,819 meters, a diameter of 127 millimeters and weigh 73.4 kg, including a 11.3 kg blast fragmentation warhead (with a 3.58 kg [7.9 lbs] explosive). The Block I and Block IA/HAS missiles are able to travel at a speed of over Mach 2 and have a maximum operational range of 5.1 nm, which was increased with the Block II version. The RIM-116C Block II Missile has a length of 2.88 meters, a diameter of 159 millimeters and weighs 91 kg. The RAM Block II Missile is claimed to have a maximum operational range of 7.5 nm, maximum speed of Mach 2.80 at sea level and can accelerate at +60G’s.

In 2017 the US Navy revealed its plans for a further upgrade of the RIM-116C RAM Block II missile as part of efforts to improve the missile’s performance against complex multi-missile raids. Known as the RAM Block IIB Raid Engineering Change Proposal (ECP) the upgrade will provide an upgraded seeker and Missile-to-Missile Link (MML) capability to counter emerging complex raid threats. Meanwhile in June 2019 Raytheon Missile Systems disclosed that the U.S. Navy has completed a series of guided flight tests for the improved the RAM Block 2A Missile at the Naval Air Warfare Center in China Lake, California from the Navy’s self-Defence test ship off the coast of Southern California. Raytheon expects to deliver the missile to the Navy by the end of 2019.

RIM-116 RAM Ship Self-Defence Weapon System & Turkish Naval Forces

The Mk49 Mod 3 Lancers supplied from RAMSYS are used in 4 ADA Class Corvettes constructed under the MİLGEM (National Vessel) Project. Aselsan and RAMSYS signed a €10 Million contract on 31 December 2007, for the procurement of one 21-Cell Mk49 Mod 3 Launcher and the electronic sub-systems required to integrate the system into the TCG Heybeliada Corvette, the first ship built under the MİLGEM Project. With this contract award, the Turkish Naval Forces became the 7th RAM user (this number has now reached 11) after Germany, the U.S., South Korea, Greece, Egypt, and the UAE. A further contract valued at €18.4 Million was signed with RAMSYS on 19 December 2008, for the supply of 25 RIM-116B-1 Block IA/HAS (24+1 [telemetry]) Missiles to be used on the TCG Heybeliada Corvette. RAMSYS also supplied 25 RIM-116B-1 Block IA/HAS (24+1 [telemetry]) Missiles and the Mk49 Mod 3 Launcher for the TCG Büyükada Corvette. The €17.6 Million contract for the 25 RIM-116 B-1 Block IA/HAS Missiles was signed on July 20, 2011.

The last two ADA Class Corvettes, TCG Burgazada, and TCG Kınalıada are planned to use RAM Block II Missiles. In this context, negotiations with both RAMSYS and Raytheon Missile Systems (via the FMS channel) for the procurement of RAM Block II Missiles to meet the Navy’s requirements were carried out during 2017 and 2018. Considering that RAMSYS may be subjected to the export license restrictions of the German Government, Turkey requested an offer from Raytheon Missile Systems in 2018 through the FMS channel and Raytheon Missile Systems announced in May 2018 that they would provide the U.S. Navy and U.S. Allies with the RAM Block II to protect ships from incoming missiles. According to Raytheon, this contract, which has options that could increase its value to US$529,8 Million, combines purchases for the Navy and the Governments of Qatar, Egypt, and Turkey. The contract is expected to be completed by 2023. However, according to our sources since the contract for the procurement of RAM Block II Missiles has not been signed yet the deliveries could not take place before the commissioning of the third ship of ADA Class Corvettes TCG Burgazada (F-513) on 4 November 2018, and the fourth and last vessel TCG Kınalıada (F-514) on 29 September 2019. According to video footage from the commissioning ceremonies, while there were only nine canisters (probably either dummy or filled with RIM-116B-1 Block IA/HAS missiles) in the Mk49 Launcher on the TCG Burgazada, the Mk49 Launcher on TCG Kınalıada was empty. Consequently, the corvettes have entered into the service of the Turkish Naval Forces without air Defence missiles