70 mm HYDRA 70 rockets

are formed by mounting up to six multiple lightweight rocket pods (seven-tube M260 or the more usual 19-tube M261), on otherwise obsolete towed M91 115 mm chemical rocket launchers or modified towed 105 mm artillery carriages. HYDRA 70 rockets can also be fired from helicopters. The programme included the development of a new higher impulse rocket motor and several forms of warhead enabling the HYDRA 70 to carry out various types of fire support function for rapid deployment or special forces when conventional artillery support would be limited or non-existent. In April 1993, the US Army had 189,000 M151 HE HYDRA 70 rockets and 41,000 with M261 multipurpose warheads. At that time a single M151 HE HYDRA 70 rocket was quoted as costing US$365, while a multipurpose rocket was US$1,424. Since 1965, BEI Defense Systems and (later) General Dynamics Armament Systems have produced well over 40 million rocket motors, warheads, ordnance components and electronic systems for HYDRA 70 air-to-air and air-to-ground applications; production has been carried out at facilities in Camden, Arkansas, and Fort Worth, Texas. Production continues to meet a series of continuation orders for the US Army, Air Force, Navy and some overseas military users. Total contract value stood at US$391.7 million in early 2001, with the maximum potential contract value being US$1.2 billion over a five-year period . Description The 70 mm HYDRA 70 fin-stabilised rocket is powered by an electrically ignited Mk 66 rocket motor originally developed by the US Navy, to enhance accuracy and range compared to earlier models such as the Mk 40; the rocket motor also produces a more subdued exhaust signature than earlier models. The aluminium-bodied rocket has three wraparound fins, a fluted exhaust nozzle and an AA2 (MK90) double-base propellant which achieves 635 kg of thrust in 38 ms; motor burn time is 1.07 seconds. The fluted nozzle spins the rocket up to 600 rpm in the launcher and 2,100 rpm after launch. Weight of the rocket motor alone is 6.16 kg complete and it is 1.062 m long. The Mk 66 MOD 3 rocket motor is the standard US Army motor. The Mk 66 MOD 2 motor is used by the US Navy, US Air Force and US Army Special Operations Forces and contains an electronic device intended to prevent radio frequencies from igniting the rocket motor. The Canadian CVR-7 C16 rocket motor has a fluted exhaust nozzle which is compatible with the HYDRA 70 system. The C17 rocket motor, a joint Bristol Aerospace/Talley Defense Systems development, has a new propellant grain geometry, a non-asbestos insulation material and modified fins. Developed from 1987 onwards, it is intended primarily for helicopter use (see under Canada below). Numerous types of warhead can be attached to the HYDRA 70 rocket motor. The most numerous is the M151 HE. M151 The M151 HE weighs 4.67 kg and contains 1.04 kg of Composition B-4 explosive in a prefragmented cast-iron 411 mm long warhead . It is fitted with the nose-mounted M433 remotely set multifunction (impact/delay) fuze, which can provide for variable depth penetration of forest canopy, buildings or bunkers - it also has a super-quick graze function. The M433 impact/delay fuze weighs 816.5 g. An alternative is the essentially similar remotely set M432 airburst fuze. There is also a M429 proximity fuze. Neither of these latter fuzes are in production in the USA. Helicopter-launched M151 HE rockets utilise the M423/M427 point detonating fuzes, the former intended for helicopters and the latter for aircraft - they differ only in the arming time. The M151 HE rocket has a maximum range of 10,400 m and a velocity of 1,517 m/s. Weight at launch is 10 kg. From 2,000 m to maximum range, accuracy is such, that the average circular error of probability is 80 m. For practice there is the M274 containing a smoke spotting charge or the completely inert WTU-1/B, the latter normally used for the ballistic testing of rocket motors. The latter are both 411 mm long and both weigh 4.2 kg . M229 Although mentioned in some references the M229 FRAG-HE warhead, intended to provide an anti-personnel and anti-materiel capability, does not appear to have been manufactured in any quantity for the HYDRA 70 system, although it continues to be marketed. The M229 warhead weighs 7.62 kg and is 677 mm long; explosive content is 2.18 kg of Composition B-4 in a prefragmented cast-iron warhead casing. M261 First fielded in 1990, the M261 warhead carries a payload of nine M73 multipurpose submunition grenades intended for use against personnel, materiel, armour and helicopters . It has been described as a MPSM HE (MultiPurpose Sub-Munition High Explosive) . The M261 warhead has a high-impact plastic nose and an aluminium alloy body with an internal base-mounted M439 remotely set fuze (weight 108.9 g). Alternatives are the M442 or M446 motor burnout fuzes that allow the M261 warhead to be used with MK4-Mod 40 rocket motors. As the base fuze functions, the nine M73 submunitions are ejected over the target area. On ejection a ram-air decelerator (a small drogue parachute) is deployed to arm the submunition's impact fuze while decelerating and stabilising the body in descent. As the fuze functions on impact the submunition's shaped 100 g Composition B charge (plus a 13 g LX-14 booster) disrupts the steel body, which is prescored internally, to create its anti-personnel effects. A single M261 warhead can distribute its submunitions over an area roughly the size of a football field. The M261 multipurpose rocket has a maximum range of 8,080 m and a velocity of 1,500 m/s. Warhead weight is 6.12 kg and it is 683 mm long. An M267 Practice warhead containing smoke-filled submunitions can be used for training. M255A1 Another payload-carrying warhead is the M255A1 anti-personnel, carrying approximately 1,200 60 grain flechettes and three tracers, again utilising the remote set M439 base fuze for timing the release point against massed infantry targets. Warhead weight is 5.7 kg and length 683 mm . It was first fielded in 1993. M247 The M247, described as a multipurpose warhead, has a unitary shaped Composition B charge weighing approximately 1 kg for employment against armour. It has an M438 base-mounted impact fuze activated by a piezoelectric element in the warhead nose. It is no longer produced. M264 The M264 Smoke warhead can generate screening smoke for up to 5 minutes and is activated by a remote set M439 fuze. The normal smoke composition involved with the earlier M259 rocket was White Phosphorus (WP) - the M264 uses a Red Phosphorus (RP) based filling of 72 presaturated pellets. Warhead weight is 4.2 kg and length 683 mm . An M156 smoke warhead has also been produced. From eight to 10 rockets are required to form a complete screen. M262 The M262 Illuminating warhead is also activated by a remote set M439 fuze and can produce 1 million candlepower illumination for approximately 2 minutes. The intention for this warhead/rocket motor combination is that they can be fired individually under the automatic control of a digital remote timer unit. One launcher fully loaded with six 19-tube M261 launch pods, can produce constant illumination of a selected area for up to 2 hours 30 minutes. The M262 is no longer produced. M257 The M257 Illuminating warhead has replaced the earlier M262 . It is 739 mm long and weighs 4.9 kg. M278 The M278 is generally similar to the M257 in operation but emits infra-red light to illuminate targets to be viewed by night vision equipment. It is 729 mm long and weighs 6.5 kg . M245 References have been found to an M245 Chemical warhead but it is assumed that any of these remaining have been withdrawn from service and are scheduled for destruction. LCPK LCPK refers to Low Cost Precision Kill and is the subject of an advanced technology demonstrator contract for a semi-active, laser-guided version of a 2.75 in rocket. The contract was awarded to Marconi Aerospace Defense Systems of Austin, Texas, and Raytheon Systems of Tucson, Arizona. The project is funded by the US Army and the US Marine Corps. It is understood that the programme is intended to improve helicopter-launched rockets and will be issued as a retrofit kit to be added to existing rockets. Authorised fuzes See text Equivalent rockets CANADA CANADA Manufacturer Bristol Aerospace Limited Type: Various - see below Description: Developed for use with the Canadian Rocket Vehicle (CVR-7) Advanced Rocket System developed by the Canadian Department of National Defense and manufactured by British Aerospace . The 2.75 in CVR-7 was developed along the same lines as the HYDRA 70, but the C15 (RLU-5002/B) rocket motor has a case-bonded, high-energy, solid-propellant fuel using an Hydroxy-Terminated-Poly-Butadiene (HTPB) binder with an 88 per cent solids content of ammonium perchlorate and ferric oxide. The motor delivers 970 kg of thrust for 1.8 seconds and has a maximum range of 14,000 m. Available warheads include: the 4.3 kg M151 HE as used with the HYDRA 70; the M229 FRAG-HE; the M249 HEDP; the M156 Incendiary/WP; the M257 Illuminating; and a long-range Mk 1 HE warhead weighing 2.7 kg. Although these rockets and warheads are in production for air-to-ground applications they have yet to be procured for the ground-to-ground role. The CVR-7 C16 rocket motor has a fluted exhaust nozzle which is compatible with HYDRA 70 motors. Manufacturer Bristol Aerospace Limited Type: C17 Description: The C17 is the latest in the CRV7 rocket series optimised for use from helicopters, such as the AH-64D Apache, and has been selected by the UK MoD. Compared to earlier models, propellant weight is increased to 3.81 kg while total rocket weight is reduced to 5.8 kg. Burn time is 0.9 second. Speed performance is stated to be 36 per cent faster than earlier models, with 40 per cent less ballistic dispersion. Standard HYDRA 70 warheads can be installed. Talley Defense Systems is the CVR7 series licensee for the USA. KOREA, SOUTH Manufacturer Hanwha Corporation Type: 2.75 in M151 Description: Mainly for helicopter applications. K99 high-performance rocket motor also produced. NORWAY Manufacturer Raufoss Technology A/S Type: 2.75 in RA79 HEISAP Description: Primarily produced for helicopters and aircraft, the RA79 is a multipurpose rocket warhead compatible with all 2.75 in rockets. It is designed to detonate only after penetrating a target exterior, combining blast and incendiary effects. The warhead weighs 5.91 kg and contains Composition A3 and zirconium. The RA82 is a Practice warhead. The RA79 is in service with Denmark, Norway and the UK. TURKEY Manufacturer Elroksan, MKEK Type: 2.75 in Rocket System Description: Primarily produced for helicopters but also launched from MAKSAM RA 7040 40-tube ground-to-ground rocket launcher with a range of 7,400 m. Involves full range of HYDRA 70 warheads.