Development The High Survivability Test Vehicle – Lightweight (HSTV-L) was developed under the direction of the TACOM project manager for Armored Combat Vehicle Technology at the US Army Tank-Automotive Command, Warren, Michigan. Following the field testing, the HSTV(L) is being used for experiments in fire-control and stabilisation. Stabilisation processing has been converted from analogue to digital. Various stabilization control algorithms are being tried along with different combinations of transducers to determine effects on gun pointing performance and the possibility of eliminating some of the expensive sensors such as gyros. The TACOM Motion Base Simulator, a huge shaker table, is being used to provide terrain input. These tests began in September 1982 and are to continue for a year or more.
Description The high survivability of this vehicle is derived from the low silhouette, high horsepower per ton, duplication of sights, improved night vision capabilities, and the lack of specific driver and gunner controls. Any crewman can shoot and both hull crewmen can drive. Although a test vehicle, the HSTV(L) is not a variable parameter test bed but an exercise in system realism for the three-man crew, hunter/killer fire control concept and low silhouette. Armament for the HSTV(L) consists of a 7.62 mm M240 machine gun for both commander and coaxial position and a 75 mm smooth bore cannon. The cannon employs a revolving breech and telescoping ammunition which enables the automatic loader to load one round per 11/2 seconds. The in battery-firing recoil mechanism has a fixed piston that allows the greater mass of recoil cylinder and breech mechanism parts to recoil during firing. The 75 mm gun and automatic ammunition feeder are designed and made by ARES Inc, Port Clinton, Ohio. Texas Instruments supplies the fire-control system which uses the hunter/killer concept. The commander uses a stabilised hunter sight that revolves independently of the turret. Once a target is selected on this sight, the turret and killer sight can be aligned with it. The gunner can then destroy the selected target while the commander returns to search with his hunter sight. Both direct vision and FLIR (Forward Looking Infra-red) optics are available for either sight. The commander can use either a binocular direct view optic eyepiece for improved clarity and reduced power drain, or a video screen. In the hull, a video screen visible to both gunner and driver receives transmissions from hunter and killer sights. The electronic fire control processor uses inputs from the sights, crosswind sensor, muzzle reference, vertical reference system, and an eye-safe CO2 laser rangefinder to compute proper gun pointing. The laser rangefinder is supplied by Raytheon. Automatic tracking and rate aid tracking can also be accomplished by the fire control processor. Both elevation and azimuth stabilisation is provided for the 75 mm gun with a slaved killer sight and an indepen¬dently stabilised hunter sight. Fire-on-the-move capabilities are improved by decoupling the yaw motion of the hull from the turret. Cadillac Gage supplies the gun control and stabilisation system for HSTV(L). Propulsion for the HSTV(L) comes from a gas turbine engine mounted beside the transmission with a cross-drive gearbox connecting the two. Avco Lycoming supplies the nonregenerative 650 horsepower modified helicopter gas turbine. The transmission is an X-300 Detroit Diesel Allison automatic four-speed with lock-up torque converter. Auxili¬ary power is provided by two 250 amp generators and a 60 gpm hydraulic pump. The hydraulic pump supplies power for the engine compartment mounted oil cooler fan and through a hydraulic slip ring; it also supplies power to the gun control system and automatic ammunition loader in the turret. Teledyne supply the fixed height hydro-pneumatic sus¬pension system. A 355.6 mm jounce and 127 mm rebound travel is possible due to the small 558.8 mm diameter road wheels. The track is an improved version of the type found on the M551 Sheridan. The man-machine interface for the HSTV(L) is of prime importance. The use of the hunter/killer concept allows both the gunner and the commander to contribute as much information as possible towards the neutralisation of the enemy. The use of pressure sensitive isometric rate controller thumb switches allows for more precise gun control while firing on the move. The driver and gunner seating positions are semi-reclined for maximum comfort in a minimum space. The tv screens considerably improve fire-on-the-move sighting clarity.
CREW 3 TEST VEHICLE WEIGHT (with instrumentation and partial applique armour) 20 450 kg POWER-TO-WEIGHT RATIO 31 78 hp/tonne GROUND PRESSURE 0.7 kg/cm2 LENGTH GUN FORWARDS 8.528 m LENGTH HULL 5 918 m WIDTH 2.794 m HEIGHT (overall) 2.414 m (to turret top) 1.994 m (to hull top) 1.422 m GROUND CLEARANCE 0.508 m TRACK 2.349 m TRACK WIDTH 445 mm MAX SPEED (road) 83.68 km/h ACCELERATION (0 to 48 km/h) 11.8 sec FUEL CAPACITY 409 litres MAX CRUISING RANGE 160 km FORDING 1.0 m GRADIENT 60% SIDE SLOPE 30% TURNING RADIUS pivot to infinity ENGINE Avco-Lycoming 650 turboshaft developing 650hp TRANSMISSION GMC Detroit Diesel Allison Division cross drive model X-300-4A with 4 forward and 1 reverse gears, single-stage, multiple-phase torque converter with automatic lock up
STEERING hydrostatically controlled differential, pivot steer in neutral BRAKES multiple wet plate, service and parking, hydrostatically applied with mechanical backup SUSPENSION hydro-pneumatic ELECTRICAL SYSTEM 24 V BATTERIES 6 × 12 V, 300 Ah ARMAMENT (main) 1 × 75 mm (coaxial) 1 × 7.62 mm MG (anti-aircraft) 1 × 7.62 mm MG AMMUNITION (main) 26 (MG) 3200 FIRE-CONTROL SYSTEM powered/manual By commander yes By gunner yes Gun elevation/ depression +45°/-17° front, +45°/-6° rear, +45°/-30° side Max rate (power) elevation/depression 1.0 rad/sec Max rate (manual) elevation/depression 10 mils/crank Min rate (power) elevation/depression 0.2 mils/sec Max traverse rate (power) 1.0 rad/sec Max traverse rate (manual) 10 mils/crank Min traverse rate (power) 0.2 mils/sec Periscopes driver 3 (×1), gunner 3 (×1), commander 8 (×1) Primary engagement sight (turret) stabilised head, FLIR CO2 laser rangefinder, tv, 2 FOV linked to all three crew members Hunter sight (turret) stabilised head, rotates independently of turret; FLIR; direct view optics, tv, 2 FOV linked to all three crew members Gunner’s sight (hull) slaved to weapon, direct view optics, 2 FOV gunner’s use only
Status: Undergoing stabilisation/fire control testing on the Motion Base Simulator, Tank Automotive Command, Warren, Michigan.