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Aviation History
1973
1973 - 0091.PDF
FLIGHT International, II January 1973 61 a remote firing device carrying arm and fire switches and connected by cable to the arm and fire interlocks of the monitor/programmer. If the latter unit is indicating "go" when the final-Are switch is pushed it activates the missile's thermal batteries, spins up the gyro and checks the warhead electronics. Correct operation of these sequences results in the propulsion system being activated, and Lance is launched. Propulsion The propulsion system has three major subsystems — pressurisation, tankage and engine. The pressurisation subsystem consists of a solid-propellant gas generator (SPGG), igniter assembly with safe and arm mechanism, hot-gas spin system, and hot-gas relief valve with two vents to regulate tank pressure. Missile spin is initiated by gas tapped from the SPGG during the first l^sec of launch. The spin is then sustained throughout flight by the four canted tabbed fins. The propellant tankage holds two storable, pre-packed liquids in her metically sealed cylindrical tanks, one behind the other. The forward tank contains the fuel, unsymmetrical dimethyl hydrazine (UDMH); the aft vessel holds the oxidant, inhibited red fuming nitric acid (IRFNA). Each tank contains a piston, guided by the fuel transfer tube in the oxidant tank and by the SPGG case in the fuel vessel. On SPGG ignition hot gases enter dead space between the central bulkhead and the pistons. Pressure builds up and pushes the pistons, cutting the static seals which prevent leakage during storage and expelling the propellants. The engine is fed through five annular manifolds, three for the oxidant and two for the fuel, and ignition takes place on contact. Dynamic wiper seals maintain separa tion of the SPGG gases from the propellants during piston travel. Lance has two concentric engines, with the thrust chamber of the booster surrounding that of the sustainer. Both engines operate during the boost phase of flight; the burn duration of the fixed-thrust booster depends on the desired range of the flight, and varies from l-5sec to 6sec. Operation of the booster is terminated at a pre set velocity by two cartridge-activated valves which shut off propellant flow under command from the accelero- meter. The single-stage missile uses a unique guidance system known as directional control, automatic meteoro logical compensation (DC-Automet), which is invulnerable to all known counter-measures. Directional control is used during operation of the boost engine. During this phase the missile's attitude is maintained by thrust-vector control via four simple on-off valves spaced at 90° intervals around the booster thrust-chamber nozzle. Fuel is injected into the exhaust stream on command from the directional-control electronics; the side forces thus created change the direction of the ;. main thrust vector and alter the missile's pitch or yaw axis. The sustainer phase of the flight is guided by the second method, Auto- met. The sustainer engine can be throttled over an infinite range of thrust levels from zero to maximum and is controlled by the Automet guidance, which maintains zero g on the accelerometer. In this way the sustainer thrust is kept equal to the missile's drag, which varies with changes in air density, etc, so that Lance flies a purely ballistic trajectory. A choice of nuclear or high- explosive warheads is offered, and the company is working with the US Army on developments including terminal guidance with a "smart" warhead using • semi-active laser guidance; terminally guided sub-missiles to seek, track and destroy armoured vehicles; a bomblet- dispersing warhead to disable station ary targets such as missile sites; and mine-laying. Early proving tests of the weapon system included high-temperature cycling, exposure to rain and salt, complete immersion in water and operation in simulated sand and dust storms. The entire propulsion system worked successfully in temperatures from -40°F to +140°F. Culmination of the testing phase was the engineering test/service test programme conducted at the White Sands Missile Range by the US Army Test and Evaluation Command, the Army's independent testing agency. Succesful results led to major com ponents of the Lance system being type-classified "Standard A" in May 1972, thus becoming standard artillery equipment. The weapon entered service last June with the 1st Battalion (Lance), 12th Field Artillery, at Fort Sill, Oklahoma. This unit formerly operated Honest Johns. LTV Aerospace was selected as prime contractor by the US Army Missile Command on November 1, 1962. In January 1963 the company was awarded a contract worth approximately $75 million for research, development, testing and engineering. A further award for $10-7 million on May 9, 1966, allowed Lance to enter the advanced pro duction engineering phase. The missile was first fired, successfully, in March 1965. On October 8, 1971, an award was made of $10-2 million for the purchase of long-lead-time items for the first production contract; a further $14-2 million brought FY72 financing up to a total of $24-4 million. LTV is now proceeding under a FY73 award of $25 million for continued production. M.H. Length 20ft 2in; max diameter 22in; span over fins (large) 55in, (small) 46-4in; max launch weight 3,351 lb; max range 70-80 n.m.; warhead 465lb nuclear or 1,0001b high-explosive; airframe aluminium alloy; max altitude 150,000ft; max flight time 200sec. This series of photographs is of a Lance test launch at White Sands Proving Grounds. The helical smoke trails show that the missile is being spin-stabilised by two gas tubes
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