RBS 88 Waverider
General Characteristics:
Type:Hypersonic Cruise Missile
Launch platform:Aircraft
Guidance:Stellar-inertial, GPS
Physical Characteristics:
Weight:1,000 kg cruiser, 2,300 kg with booster
Length:4.0 m cruiser, 6.3 m with booster
Diameter:0.6 m
Payload:
RBS 88A:4x Rb 71 loitering munitions
RBS 88B:2x PC 100S hart target submunitions
Performance Characteristics:
Propulsion:Dual mode scramjet (sustainer), solid fuel rocket (booster)
Speed:Mach 8.0
Cruise altitude:30,000 m
Range:2,500 km
Overview:
The RBS 88A Waverider cruise missile is a long range, air launched hypersonic cruise missile intended to penetrate heavily defended airspace and destroy hardened and time-critical high value targets deep inside protected enemy airpsace.
Airframe & Propulsion:
The Waverider is a two-stage missile and consists of a scramjet powered cruiser stage attached to a solid-fuel rocket booster. After being released from the aircraft the booster is ignitor and accelerates the missile to a speed of mach 4.5 at an altitude of 25,000 meters at which point the scramjet engine is lit and the solid fuel booster discarded. The cruiser stage has a rectangular, lifting-body geometry and consists of a wedge nose inlet, an under slung scramjet engine, and four rear mounted control fins. The cruiser is constructed primarily from Ti-6242S (Ti-6Al-2Sn-4Zr-2Mo-0.1Si) near-alpha titanium alloy covered with a silica-based ceramic matrix composite (CMC) thermal protection system designed to endure the >1,000° C skin temperatures of mach 8 cruise. The wedge shaped nose of the cruiser, which has to endure a leading edge temperature of over 1,600° C during mach 8 cruise, is constructed from carbon/carbon (C/C) ceramic matrix composite with a HfB2‐SiC (silicon carbide fiber reinforced halfnium diboride) ultra high temperature ceramic (UHTC) coating. The four control fins of the cruiser are constructed from cast titanium-aluminide (TiAL) intermetallic alloy with UHTC coated carbon/carbon (C/C) leading edges and are actuated using a 55 MPa hydraulic system driven by power takeoff from the engine fuel turbo-pump. The cruiser stage is attached to a solid-fuel booster which consists of a graphite-epoxy wound solid fuel rocket motor with a thrust-vectoring nozzle and four rear mounted control fins which provide aerodynamic control during booster operation.
The cruiser stage of the Waverider is powered by an SDI SRM 200 scramjet engine, a rectangular dual-mode scramjet (DMSJ) engine integrated into the underside the missile. The scramjet is fed using a fixed geometry 2-dimensional mixed compression nose inlet which consists of an aerodynamic compression ramp, sidewalls, a cowl lip, and an inlet duct which leads into the scramjet throat. The inlet ramp and walls of the scramjet engine are constructed from C/SiC (Carbon fiber-reinforced silicon carbide) ceramic matrix composite with service temperature of 1,900° C and are actively cooled by pumping endothermic hydrocarbon fuel through heat exchangers located alongside the walls of the scramjet engine where endothermic cracking of the hydrocarbon fuel is used to reduce the extremely high heat load experienced by the scramjet engine structure at hypersonic speeds. The dual mode scramjet engine that powers the waverider is capable of operating as either a ramjet or scramjet, known as "dual-mode" operation. The dual-mode scramjet consists of four sections, an inlet, a constant volume isolator, a combustor, and a nozzle. The dual-mode scramjet is lit at mach 4.5 and initially operates as a ramjet, decelerating the flow to subsonic speeds before combustion, with combustion taking place at constant pressure. As the mach number is increased past 5 the the subsonic ramjet transitions into the dual-mode regime, where the combustor inlet Mach number is increased enough such that a thermal throat is created in the combustor and a pre-combustion shock train is generated. The isolator is designed to prevent this shock train from reaching the inlet to prevent inlet unstart which would choke the engine of airflow. In this regime the combustor operates in a mixed subsonic/supersonic, or dual-mode. As the Mach number is further increased past 6 the pre-combustion shock train moves out of the isolator and the combustor operates in the supersonic mode with combustion taking place at a constant volume, rather than at a constant pressure like in the subsonic combustion regime. Endothermic hydrocarbon based fuel is injected into the combustion chamber via a series of regeneratively cooled ramp injectors constricted from sintered silicon nitride (Si3N4) which are recessed into the walls of the scramjet. The ramp injectors are designed to provide the minimum possible flow losses and maximize fuel mixing with supersonic airflow to maximize combustion efficiency.
The scramjet engine is fueled with methylcyclohexane (MCH), an endothermic hydrocarbon fuel which undergoes thermal cracking at high temperatures in the presence of a catalyst, undergoing catalytic dehydrogenation and yielding hydrogen gas and new hydrocarbon compounds while absorbing a significant amount of heat without forming any surface deposits. The MCH fuel is housed in a nitrogen inerted graphite/polyimide composite alloy tank in the center of the cruiser where it is pressurized to 100 bar using a turbopump and then pumped through a set of catalyst lined heat exchangers constructed from beta 21S (15Mo2.7Nb3Al0.2Si) beta titanium alloy located inside the C/SiC walls of the engine. The B21S titanium alloy is insulated from the C/SiC walls with a small air gap, ensuring the beta 21S titanium stays within its 675° C operating temperature. Inside the heat exchangers the catalyst and the radiant heat from the C/SiC scramjet walls causes the methylcyclohexane to decompose into hydrogen, cyclohexene, and various alkylcyclohexenes. The gaseous hydrogen, cyclohexene, and alkylcyclohexenes are then expanded through a gas turbine driving the fuel turbopump before being injected through the recessed ramp injectors into the combustion chamber where the fuel ignites with the combustion chamber air and is then expanded through a high-expansion ratio SERN (single expansion ramp nozzle) to generate thrust.
Guidance:
The Waverider is guided in flight by a stellar-inertial guidance system which provides highly accurate midcourse guidance without reliance on GPS signals. The guidance system consists of a 6-axis SDI TNS 450 tactical-grade timing and inertial measurement Unit (TIMU) which combines three milli-Hemispherical Resonator Gyroscope (mHRG) and three quartz resonating beam accelerometers (RBA) in a low SWaP package (500 cc volume, <1.0 kg mass, <5 watts max power consumption) package which provides <0.0003°/√hr gyro angle random walk and < 0.0001 °/hr bias stability performance coupled to a CCD star-tracker camera which looks upward through a circular window located in the upper fuselage of the cruiser stage. The star tracker employs is uses to provide position fixes in flight accurate to within 90 meters in broad daylight using a pre-programmed 57 star catalog. The IMU and stellar sensor are further augmented by a 48 channel dual-frequency (L1/L2) SAASM (Selective Availability Anti-spoofing Module) based GPS receiver with M-Code compatibility and >90 dB J/S digital anti-jamming capability whuch employs twin controlled reception pattern antennas (CRPAs) on the aft fuselage of the cruiser with adaptive beam steering and directional nulling capability with ionosphere correction capability and simultaneous L1/L2 operation which provides the weapon with <1 meter position accuracy capability. in heavy GPS jamming environments.
Warhead:
RBS 88A: The RBS 88A is designed to attack time-critical relocatable targets including mobile surface-to-surface and surface-to-air missile batteries and dispenses a payload of four Rb 71 loitering autonomous submunitions onto the target area. Each Rb 71 submunition weighs 38 kilograms and consists a maneuvering airframe 90 centimeters long with a 1.2 meter wingspan powered by a small turbojet engine which contains a solid state LADAR sensor with automatic target recognition (ATR) capability coupled with a multimode explosively formed penetrator warhead. The Rb 71 is powered by a 130 N thrust SDI RM55 micro-turbojet engine which gives the munition a maximum speed of 430 kph (Mach 0.30) an an altitude of 250 meters AGL with a maximum range of 185 kilometers and a maximum flight endurance of 30 minutes. The munition's seeker consists of a solid state three-dimensional imaging LADAR sensor employing an uncooled, diode pumped Nd:YVO4 laser with a 1.06 μm wavelength. The LADAR seeker is capable of acquiring vehicle size targets at a range of 6 km in clear weather and produces high resolution 3D imagery which is processed by an automatic target recognition processor which compares the LADAR image to a database of threat vehicles.
When the munition identifies a target it cuts its turbojet engine and glides towards the target to a point directly overhead where the munition's downward firing explosively formed penetrator (EFP) warhead is then fuzed. The warhead weighs 8.0 kilograms including 2.5 kg of polymer bonded explosive (92% HNIW, 4.8% BDNPA/F, 3.2% CAB) and can be miniated in one of three modes depending on target type and standoff range. Against armored targets the warhead is fired in a long rod penetrator mode which is designed for maximal armor penetration. Alternatively if fuzed from a greater altitude over the target the warhead is fired as an aerostable slug which maintains aerostability over greater standoff ranges while still having the capability to penetrate the thinner roof armor of most vehicles. Against softer targets such as TELs or radars the warhead is used in a directed fragmentation mode which causes the tantalum liner to break up into shrapnel which is projected towards the target area like a large shotgun blast.
RBS 88B: The RBS 88B is designed to penetrate and destroy hardened aircraft shelters, command bunkers, and other hard targets and contains a payload of twin PC 100S bombs which are released from the cruiser stage at high supersonic velocity prior to impact. Each PC 100S weighs 110 kilograms and employs a 100 kilogram hardened penetrator warhead consisting of a nickel-molybdenum-cobalt maraging steel (8Ni-14Mo-20Co-Fe) sub-caliber penetrating warhead filled with 20 kilograms of enhanced blast thermobaric explosive (50% HMX, 30% Al powder, 20% PCP/TMETN energetic binder/plasticizer). The warhead is fitted with a base mounted hard target smart fuze (HTSF) containing a precision MEMS accelerometer and micro-controller which features void sensing, layer counting, depth of penetration, and time time delay after impact fuzing modes. The detonator is entirely electronic with no moving parts and uses an exploding foil initiator (EFI) detonator to initiate the main explosive charge. The warhead is coupled to a guidance and control section consisting of a 6-axis SDI 500 MEMS based inertial measurement unit along with a control section featuring three flip-out grid fins actuating using brushless DC electro-mechanical servomotors. With a terminal impact velocity of over 1,300 meters per second (mach 4) each PC 100 munition is capable of penetrating over 6 meters of 34 MPa (5,000 psi) reinforced concrete before exploding