105mm Self-propelled Howitzer M52.

The M52 was based on the M41 tank, but with the drivetrain reversed. The sprocket was mounted to the front, and a large trailing idler was added. The driver's position is visible on the turret left front corner, and a ventilating blower duct is directly behind it. Note the two-piece driver's door; the upper section could be opened without opening the lower section. Spare T91E3 track blocks are stored on the front of the turret. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

Pioneer tool stowage on the turret side can be seen, as well as the arrangement of the rear doors. Ammunition racks were accessible through the rear doors. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

A late-production vehicle is seen here from the rear. On early production vehicles, the lower left turret door was opened by opening the upper left door, then by releasing two locking handles on the outside of the lower left door and swinging the door down. On late vehicles, the two locking handles on the lower left door were released, then the door was opened and folded in the center. A spring-loaded door catch was used to secure the door in the open position. Early vehicles also had a ladder secured to the lower left door. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

Further tool stowage and crew doors are visible on the turret roof. The driver was at the front left of the turret with the gunner to the front right. The gunner's periscope and panoramic telescope can be seen emerging from the front right corner of the turret roof. The commander was at the right rear of the turret. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The internal arrangement is revealed in this cross-section. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The turret has been removed, allowing a view of the turret race and interior including the turret basket. The hull front is to the right of the image, and an engine air cleaner is visible below the pointer for the race ring guard. (Picture from TM 9-7205-1.)

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105mm Self-propelled Howitzer M52.

The turret basket can be seen in the process of being removed from the hull. (Picture from TM 9-7205-1.)

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105mm Self-propelled Howitzer M52.

The commander's cupola is detailed in this picture. The cupola body was bolted to the turret roof, and this was equipped with six vision blocks. The door race plate could be rotated through 360°, and a periscope M15A1 could be mounted in it. An azimuth scale and pointer were on the interior of the cupola for use with the periscope. A rotating ring, to which the machine gun mount was attached, revolved on the stationary ring. (Picture from TM 9-7205-1.)

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105mm Self-propelled Howitzer M52.

The commander's position is shown here. Like the gunner's and driver's seats, three vertical positions were available. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

Details of the driver's periscopes and counterbalanced hatch door are shown in this picture. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The driver's stations in an early (left) and late (right) vehicle are detailed in this image. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The driver's instrument panel is labeled here. A. Driving light switch. B. Driving light controls. C. Transmission low oil pressure warning light. D. Warning light panel. E. Engine low oil pressure warning light. F. Engine magneto switch. G. Engine starter switch. H. Fuel cutoff switch. J. Engine oil pressure gage. K. Master relay switch. L. Fuel gages. M. Auxiliary switch. N. Safety switch. P. Transmission high oil temperature warning light. Q. Engine high oil temperature warning light. R. Engine magneto booster switch. S. Master relay switch indicator light (late vehicles only). T. High beam indicator light (late vehicles only). U. Blackout receiver switch (late vehicles only). V. Generator warning light. W. Auxiliary generator warning light. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

Although the auxiliary generator and engine were eliminated during production, provision for mounting one and its controls remained. The control box for the auxiliary generator and engine were mounted along the right side turret wall, along with the choke control for the auxiliary engine and control boxes for the bilge pump (only installed when the deep-water fording kit was installed) and personnel heaters. The controls for an early (left) and late (right) vehicle are both illustrated. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

As originally designed, the prototype T98E1 featured an hydraulic traversing and elevating system, but trouble with the prototypes led to modifications including the deletion of the hydraulic system. (Picture from TM 9-7205-2.)

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105mm Self-propelled Howitzer M52.

The manual turret traversing handwheel was situated to the gunner's front right; his seat is at the lower right corner of the image. The handwheel drove bevel gears linked to a universal joint shaft and gear train in the turret traversing drive mechanism; the pinion of this mechanism meshed with the turret race ring gear. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The elevation handwheel was to the gunner's left. This handwheel operated a worm and pinion gear in the speed reduction unit that drove a pinion that meshed with the elevating segment on the howitzer mount. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The gunner's control box was attached to the left side of the his seat support. On the side of the box opposite the accessory outlet socket was the on/off switch for the ventilating fan. The unlabeled forward circuit breaker on the box was for the firing circuit; this breaker was inoperative. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The unity periscope M23 and 4x telescope M101 were used to lay the howitzer in direct fire. The reticle for the M101 was graduated for the 105mm HEAT shell M67. Both the M23 and M101 had 10° fields of vision; the line of sight through the M23 was depressed 2°15' ± 2' in elevation with respect to a line of sight through the periscope's upper window. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The panoramic telescope M100 was a 4x device with a 10° field of view, and was used to lay the howitzer for indirect fire. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The panoramic telescope M100 was mounted in the telescope mount M99 or M99A1, the latter of which is the version featured in this picture. The mounts incorporated a cant correction mechanism that, when cross- and longitudinally-leveled, indicated the error in azimuth when sighting through the panoramic telescope at a fixed aiming point that was induced by elevating the howitzer with the trunnion canted. The M99 had a curved support assembly with an accordion-type rubber dust boot; the M99A1 had a worm and nut mechanism instead of the curved support, and the rubber dust seal was a plain type. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

This overview of the gunner's position shows both the spatial relationship between the panoramic telescope M100 and the telescope M101 as well as the traversing and elevation handwheels. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

More details of the gunner's telescope mount are shown in this image. (Picture from FM 6-77 105-mm Howitzer M52 Self-propelled.)

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105mm Self-propelled Howitzer M52.

A rotary ready rack occupied the rear of the turret. When a shell was removed, the cam on which it rested was released, and the rack would automatically spin until arrested by the next cam depressed by a shell. Early racks, shown on the left, had a cam release lever that could be turned up and pushed in to let the rack spin freely. Instead of the cam release lever, late-production racks (center image) could be spun by stepping on a foot pedal, shown on the right. When a shell was removed from the ready rack, it was placed on the zoning tray in front of the rack, where the shell was split and charged with powder. The tray was then moved left on integral rollers, so that the fuse setter mounted by the tray could be used. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

While the commander, gunner, and driver sat in bucket-type seats with removable backrests, the loaders made due with seats that could be installed when desired onto supports connected to the turret basket. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

A partially exploded view of the 105mm howitzer M49 is given here. It used a vertical sliding breechblock, and weighed 930lb (420kg) complete. Maximum range was 12,150 yards (11,110m). (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

Early (top) and late (bottom) versions of the howitzer mount M85 are shown here. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

A cross-section of the recoil system is diagrammed in this image. It was a concentric hydrospring constant recoil distance type with a normal recoil length of 11.75" (29.85cm) and a maximum of 13" (33cm). When the ordnance was fired, the recoil piston attached to the howitzer tube was driven rearward with the tube itself. As the piston moved, recoil oil flowed around it, and the farther rearward the piston traveled the smaller the clearance between the piston and the bore of the cradle became, thereby increasing the resistance of the flow of the oil. The recoil spring was also compressed during firing, assisting with the arrest of rearward motion. During counterrecoil, the compressed spring forced the ordnance back into battery, and a buffer regulator cushioned the impact so the howitzer returned to battery with a minimum of shock. Including the replenisher, the recoil system's capacity was 3.5gal (13L) of oil. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The replenisher assembly constantly kept the recoil oil under pressure. It allowed the oil to expand as its temperature increased by forcing the internal sprung piston to the rear, and this same sprung piston would force additional oil into the recoil system due to contraction due to decreased temperature, leaks, etc. The indicator rod, attached to the piston, was marked with graduations alerting the crew when to fill or bleed the replenisher. Late-production vehicles (right) had an overflow storage tank connected to the replenisher. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The headlight clusters of an early (top) and late (bottom) vehicle can be compared. Note the more open brush guard design on the late machine. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The various engine and transmission doors and grilles are labeled on this late vehicle. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

This early machine has the transmission access doors opened. Note the headlight brush guard design in contrast to the late vehicle. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The engine compartment is shown here with the covering plates removed. The letters refer to disconnect points for the engine and transmission. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The engine compartment is shown here with the engine and transmission dismounted. The two fuel tanks were filled individually: the left tank held 93gal (350L) and the right tank 81gal (310L). (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The top of the engine and transmission, shared with the 76mm gun tank M41 are labeled in this image. Its compression ratio was 5.5:1. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The bottom of the engine and transmission can be seen. Running at 2,800rpm, the engine could be expected to consume 1gal (3.8L) of oil every hour. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

Parts of the suspension are labeled in this image. Although a 12-tooth drive sprocket is shown mounted, 13-tooth sprockets began to be supplied as replacement parts by at least September 1957. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

Another view of the suspension and hull side is provided with the running gear removed. The design originally had a shock absorber connected to the trailing idler wheel, but this was omitted during production. The vestigial mounting holes behind the rear road wheel's bumper spring seem surprised at the shock absorber's absence. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The track adjustment gear case contained a worm gear used to adjust the idler wheel to tighten or loosen track tension. (Picture from TM 9-7204.)

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105mm Self-propelled Howitzer M52.

The crew positions are shown here mounted for travel (on the left) and ready for action (on the right). CS is the chief of section, G is the gunner, D is the driver, 1 is the assistant gunner, and 2-5 are cannoneers. (Picture from FM 6-77 105-mm Howitzer M52 Self-propelled.)

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105mm Self-propelled Howitzer M52A1 at the Patton Museum of Cavalry and Armor.

This M52A1 is differentiated by its fuel-injected vice carbureted engine, and is externally similar to the earlier version.

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105mm Self-propelled Howitzer M52A1 at the Patton Museum of Cavalry and Armor.

The outboard guard on the right side of the turret roof was for the gunner's periscope M13, and the larger inboard guard protected his panoramic telescope M100.

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105mm Self-propelled Howitzer M52A1 at the Patton Museum of Cavalry and Armor.

This rear view shows the turret and hull doors. A towing pintle is located at the center of the bottom hull. The commander's cupola with its .50cal machine gun mount is visible on the right side of the turret roof, and an antenna mast base is near the center of the turret roof rear.

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Last updated 11 Dec 2021.
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© Copyright 2001-21 Chris Conners