[Legbreaker]

Found the following info just through googling "XM274"

Jane’s Light Tanks and Armoured Cars 1984 by Christopher F. Foss. It is posted here for educational purposes:

High Survivability Test Vehicle (Lightweight)

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.

SPECIFICATIONS

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.

Manufacturer: AAI Corporation, Box 6767, Baltimore. Maryland 21204, USA.

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HSTV(L) undergoing stabilisation/fire-control testing on Motion Base Simulator, TACOM, Warren, Michigan (US Army)

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Above: Typical target engagement by HSTV(L)

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HSTV(L) with all hatches closed and armoured track skirts fitted

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Cutaway drawing of HSTV(L) showing position of main components of Texas Instruments fire-control system

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Three-view drawing of HSTV(L)

Rapid Deployment Force Light Tank (RDF/LT)

Development
The Rapid Deployment Force Light Tank (RDF/LT) has been designed as a private venture by AAI Corporation which has already built the prototype of the High Survivability Test Vehicle (Lightweight) under contract to the United States Army Tank-Automotive Command.
The prototype was shown for the first time in October 1980 when it was said by the company that it could be in service by 1984, if a decision on production was taken in the immediate future.
The vehicle is airportable: the Lockheed C-5B transport aircraft can carry eight RDF/LTs, the C-130 and C-141 could each carry two and the Navy/Marine Corps CH-53E helicopter can carry one slung under its fuselage.
This vehicle, with some changes and improvements in armour protection, is AAl’s entry in the MPGS competition.

Description
The hull of the RDF/LT is made of all-welded aluminium armour with the driver sitting at the front of the hull on the left and the commander/gunner to his right. Both crew members have a single-piece hatch cover that opens outwards and has three integrated periscopes. Between the driver and commander/gunner, in the upper part of the glacis plate, is the hull-mounted auxiliary sight.
The main armament consists of a 75 mm ARES cannon mounted in the centre of the hull behind the crew. The 75 mm ARES cannon is fed from an automatic magazine holding 60 rounds of APFSDS and multi-purpose ammunition and when used for indirect fire has a maximum range of 12 000 metres. To the right of the main armament there is a coaxial 7.62 mm machine gun.
Mounted above and behind the main armament is the stabilised rotary head which is the primary sight. The main armament is fully stabilised and the fire-control system includes a digital computer. The fire-control system is similar to that of the HSTV(L) and is fully described in that entry.
The engine and transmission are mounted at the rear of the hull and the complete powerpack is on extensible rails to facilitate maintenance in the field.
The torsion bar suspension consists of five dual rubbertyred road wheels with a drive sprocket at the rear, idler at the front and one return roller.
Appliqué steel armour can be fitted to the RDF/LT for increased protection. As an alternative to the 75 mm ARES cannon which is mounted in an unmanned turret and fitted to the prototype vehicle, an AAI Universal One-Man Turret which is also armed with a 75 mm ARES cannon, fed from an automatic loader, can be fitted.

Variants
In 1982 AAI announced a new version of this vehicle fitted with a new one-man turret also armed with the ARES 75 mm automatic cannon. This has a single-piece hatch cover opening to the rear, six periscopes for all round observation and forward and to the right of the hatch is a stabilised sight for target acquisition/firing.

SPECIFICATIONS
(RDF/LT with three man crew and turret mentioned above)

CREW 3
WEIGHT (combat) 13 426 kg (unloaded) 12 247 kg
POWER TO WEIGHT RATIO 26.07 hp/tonne
GROUND PRESSURE 0.49 kg/cm2
LENGTH GUN FORWARDS 8.235 m
LENGTH HULL 5.569 m
WIDTH 2.54 m
HEIGHT (top of sight) 2.286 m
AXIS OF FIRE 1.562 m
GROUND CLEARANCE 0.50 m
MAX ROAD SPEED 64 km/h
FUEL CAPACITY 378 litres
MAX CRUISING RANGE 500 km
FORDING 1 m
ENGINE General Motors 6V53T, turbo-charged, 6-cylinder diesel developing 350 hp
TRANSMISSION General Motors, Allison Division, X-200 cross drive, automatic
SUSPENSION torsion bar
ELECTRICAL SYSTEM 24 V
BATTERIES 6 × 12 V. 190 Ah
ARMAMENT (main) 1 × 75 mm (coaxial) 1 × 7.62 mm MG
AMMUNITION (main) 60 (coaxial) 2600
FIRE-CONTROL
turret power control hydraulic/manual
by commander yes
by gunner yes
Gun elevation/ depression +40°/-15°
Turret traverse 360°
Turret slew rate 60°/s
Gun elevation rate 60°/s

Status: Prototype. This vehicle has been designed to meet the US requirement for a Mobile Protected Gun System.

Manufacturer: AAI Corporation, PO Box 6767, Baltimore, Maryland, 21204, USA.

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Powerpack of AAI RDF/LT slides out for ease of maintenance and field replacement

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Prototype of AAI Rapid Deployment Force Light Tank

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Rapid Deployment Force Light Tank fitted with Universal One-Man turret armed with 75 mm ARES gun

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75 mm ARES automatic gun as fitted to the HSTV-L, RDF Light Tank and the High Mobility Agility Test Vehicle (HIMAG)

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AAI Rapid Deployment Force Light Tank prototype fitted with new one-man all-cast turret armed with 75 mm ARES automatic gun undergoing trials in 1982

The following idea seems to be a good option for T2K. The M32 76mm gun (pulled from reserve stores) with updated ammo should be enough to give the Chinese a fighting chance against the Soviets...

13.2 Tonne Rapid Deployment Force Light Tank (RDF/LT)

Development
The original AAI Rapid Deployment Force Light Tank (RDF/T), described in the preceding entry, cannot be exported at present as the ARES 75 mm automatic cannon has not yet completed its US Army funded development.
In 1982 AAI announced that they had built the prototype of a 13.2 tonne RDF/LT fitted with a new two-man turret armed with the same 76 mm M32 gun as the M41 light tank’s. This was phased out of US Army service some years ago, although it remains in service with many other countries. The prototype uses the chassis of the original RDF/LT but production vehicles would have a slightly different hull and the description below relates to this. A Lockheed C-130H aircraft can carry two 13.2 tonne RDF/LTs.

Description
The hull of the RDF/LT is of all-welded aluminium construction. The driver is seated at the front of the hull on the left with 30 rounds of 76 mm ammunition stowed horizon¬tally to his right. The driver has a single-piece hatch cover that opens to the left, in the forward part of this are three periscopes the centre one of which can be replaced by a passive periscope for night driving.
The all-welded turret is in the centre of the vehicle with the commander seated on the left and the gunner on the right. Both have a single-piece hatch cover, six periscopes for all round observation and an M32 periscope for aiming the armament. The gunner’s M32 periscope incorporates a laser rangefinder.
Main armament consists of a 76 min high velocity M32 gun which is installed in the M41 tank. In addition to the range of ammunition originally developed for this weapon, and fully described in the entry for the M41 light tank, AAI have developed a new round of APFSDS-T ammunition based on their experience in developing ammunition for the ARES 75 mm automatic. This has already been tested in Denmark during trials with an M41 light tank. According to AAI, this projectile has three times the probability of killing a T-62 tank at a normal combat range of 1500 metres than the 105 mm M456 HEAT-T round and only slightly less kill probability at a similar range to the 105 men M735 APFSDS-T round. A 7.62 mm M240 machine gun is mounted coaxially with the main armament.
A Cadillac Gage stabilisation and weapons control system is fitted as standard enabling the vehicle to fire on the move with a high probability of a first round hit. Optional fire-control systems include an M32 sight with an AN/VSG-2 Tank Thermal Sight or a digital tank fire-control system with the AN/VSG-2 Tank Thermal Sight, AN/GVS-5 laser rangefinder and a digital ballistic computer.
The engine and transmission are mounted at the rear of the hull and the complete powerpack is on extensible rails to facilitate maintenance in the field.
The torsion bar suspension consists of five dual rubber tyred road wheels with the drive sprocket at the rear, idler at the front and one return roller which is positioned above the second and third roadwheel stations. Track is the M113.

SPECIFICATIONS

CREW 3
WEIGHT (combat) 13 200 kg (unloaded) 11 800 kg
POWER TO WEIGHT RATIO 26.5 hp/tonne
GROUND PRESSURE 0.48 kg/cm2
LENGTH GUN FORWARDS 7.34 m
LENGTH HULL 5.569 m
WIDTH 2.54 m
HEIGHT (overall, M32 sight) 2.235 m (hull top) 1.562 m
GROUND CLEARANCE 0.50 m
MAX ROAD SPEED 64 km/h
FUEL CAPACITY 378 litres
MAX CRUISING RANGE 500 km
FORDING 1 m
GRADIENT 60%
ENGINE General Motors 6V-53T, turbo-charged, 6-cylinder diesel developing 350 hp
TRANSMISSION General Motors, Allison Division, X-200 crossdrive, automatic
SUSPENSION torsion bar
ELECTRICAL SYSTEM 24 V
BATTERIES 6 × 12 V, 190 Ah
ARMAMENT (main) 1 × 76 mm (coaxial) 1 × 7.62 mm MG
AMMUNITION (main) 50 (coaxial) 2600
FIRE-CONTROL
turret power control hydraulic/manual
by commander yes
by gunner yes
GUN ELEVATION/DEPRESSION +22°/-10°
TURRET TRAVERSE 360°

Status: Prototype.

Manufacturer: AAI Corporation, Box 6767, Baltimore, Maryland 21204, USA.

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Prototype of AAI 13.2 tonne Rapid Deployment Force Light Tank undergoing initial cross-country trials in 1982

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AAI 13.2 tonne Rapid Deployment Force Light Tank prototype showing new turret armed with 76 mm M32 gun which can fire a new APFSDS-T projectile developed by AAI

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Cutaway drawing of 13.2 tonne Rapid Deployment Force Light Tank showing crew positions and ammunition stowage

An interesting idea....
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