Perhaps the most striking feature of the M103 heavy tank was its massive turret, in which the commander sat far to the rear. The bore evacuator on the 120mm gun is visible near the muzzle. The gun travel lock is stowed on this vehicle, but when in use it swiveled upward and was supported by two legs on early tanks, and later vehicles added a third leg which was stowed on the rear deck. The engine exhaust was vented through the rear deck, and a deflecting shield was installed to direct the hot air rearwards and away from the turret bustle, although that feature seems to be missing from this vehicle. (Picture courtesy Armor Foto.)
This vehicle, sitting in the Patton Museum's motor pool, is actually the first pilot T43, the pre-production model of the M103. On production tanks, the headlight brush guards featured a round top, and the exhausts for both personnel heaters exited the hull roof to the right of the driver's hatch, instead of one on each side as seen here. Since this is pilot number 1, the driver is provided with a small hatch and three T36 periscopes. Tanks with serial number 5 and greater received three M26 periscopes. The right-hand headlight group consists of, from left to right in the picture, the headlamp, the small blackout marker light, and the horn. On the the tank's left side, the blackout lamp and another blackout marker light can be seen, and another headlamp is just out of view. The apertures for the two coaxial machine guns are visible on each side of the main gun, and a three-rung ladder is visible welded to the turret's right side.
This shot shows a closer detail just to the left of the driver's hatch. The pipe with the long extension was used to vent the exhaust from one of the crew compartment heaters. The smaller pipe just ahead of the exhaust pipe was the bilge pump outlet. The external fire extinguisher activation controls were placed under the guard behind the heater exhaust pipe.
The exhaust port for the main engine is visible on top of the rear deck. Just visible in front of the exhaust outlet is a bulge in the turret floor that indicates where the gunner's seat is located. The grille doors to the rear of the deck provided access to the tank's Cross Drive transmission, and just ahead of these is the transmission oil filler cover. The grille door sloping down to the right was the right-hand main engine access door.
The yellow hook is resting on the transmission access grille doors, and a lifting eye can be seen on the rear of the hull.
The extreme rear placement of the tank commander can be seen here, as his cupola is visible on the turret roof. Grab rails are welded around the turret, and the ladder is again visible towards the turret front.
The left-hand blister for the M14 rangefinder is illustrated here. Since this is a pilot tank, it is not fitted with the production cupola that provided remote-control fire for the .50cal machine gun. The cupola on this tank is identical to that on the medium tank M47. The feature that identifies this vehicle as pilot number 1 is barely visible in this picture--a pistol port is placed in the turret side below the grab rail, the border of which can just be seen at the very bottom of the image.
The front loader's escape hatch and hold-open latch are visible in this photo. To the right of the commander's cupola in the image is the turret ventilator dome, and the gunner's periscope guard is on the other side of the cupola. The gunner's periscope is actually part of a removable turret top plate that runs across the turret roof and from in front of the commander's cupola to behind the loader's hatch.
A better view of the turret top plate, and its lifting eyes, can be seen here.
The first pilot T43 was armed with the 120mm gun T122, which was replaced with the 120mm gun T123 that became the M58 gun found in production tanks. The chamber pressure in the T123 was 26% greater than that of the T122, yielding a higher muzzle velocity. Production tanks also featured a cylindrical counterweight placed ahead of the bore evacuator that also acted as a blast deflector.
The tank's elliptical hull design is easily seen in this imposing view. The counterweight and bore evacuator on this vehicle can be contrasted to the early prototype above.
Details of the running gear are revealed here, although the first shock absorber is out of frame. The commander's position at the extreme rear of the turret can be better ascertained when viewing the tank in profile. A handrail is visible on the turret side, a stowage rack lines the rear of the turret, and there is an air cleaner for the diesel engine mounted on the tank's fender.
The rounded headlight guards are easily contrasted with those on the pilot tank above, although the lights themselves are absent on this tank. The personnel heater exhausts are routed to the tank's right, although the bilge pump outlet remained in its original position to the tank's left. The driver was also provided with the larger hatch. The bulge in the turret for the gunner's former position is easily seen on this tank, although he was moved forward in the M103A1.
The exhaust on this tank is vented through M60-style louvres instead of through a port in the rear deck. This redesign necessitated a new gun travel lock, which is in use on this vehicle. The towing pintle is obvious in the center of the rear hull, and above and to either side of this are transmission access plates. Taillight guards are to the outside of the transmission access plates.
Modifications to the tank commander's cupola are visible here compared to the early style on the tank above. The latter style did not offer the option of firing the machine gun while buttoned. The structure directly in front of the TC's cupola is a vane sight that assisted the commander in targeting the 120mm gun. The new position of the gunner can be ascertained by the location of his periscope in front of the turret hatch (the periscope opening in his former position has been blanked off). The receptacle opposite the gunner's periscope was for providing power to the optional mantlet-mounted searchlight.
The driver's controls are shown here. The steering wheel is similar to that found in the M48 tank. The tachometer is to the left of the steering wheel, and the speedometer is on the opposite side. The transmission selector lever is visible to the right side of the picture, and the accelerator and brake pedals are on the driver's right and left, respectively. The headlight dimmer switch is just to the left of the brake pedal.
When in reverse, steering the wheel counterclockwise would result in the tank's rear swinging to the right; a leftward movement of the rear was performed by turning the wheel clockwise. Turning the wheel to the right or left while the vehicle was in neutral would cause the front of the tank to pivot to the right or left, respectively.
The driver's accessories control panel was placed to his left, and projectile and charge stowage racks are visible behind the panel. Ammunition stowage was placed on both sides of the driver.
This picture was taken from the driver's compartment looking back into the turret. The breech of the 120mm gun M58 takes up most of this image. The gunner's instruments are visible to its right, and ammunition charge stowage is visible on the opposite turret wall.
The floor of the turret basket is the subject of this image. The two tubes on the basket floor to the left in the picture are the elevation motor generator and the traverse motor generator and accessory box assembly. Hull ammunition stowage can also be seen to the extreme left of the image.
More details of the stowage on the turret's left side are visible here, as well as a seat for the left loader. The box to the front of the turret was for .30cal machine gun ammunition.
The gunner's and loaders' hatch is visible in the turret roof here, and the gunner's position and controls are to the right of the 120mm gun's breech. The M14E1 ballistic computer is on the bottom to the front of the gunner, and a browpad for his sighting instruments is visible near the turret roof. His periscope is missing from this vehicle, however.
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