Medium Tank M45.
Compared to the M26 tank whence it was derived, the short ordnance on the M45 is immediately obvious. The 105mm howitzer M4 weighed 1,140lb (517kg) compared to 2,450lb (1,110kg) for the 90mm gun M3, so the howitzer shield and turret front armor were thickened to better balance the turret. A howitzer travel lock was mounted on the hull roof between the drivers' hatches, and the aperture for the coaxial machine gun is visible through the canvas cover. (Picture from ORD 9 SNL G-226 List of All Service Parts for Tank, Medium M26; Tank, Medium, M45.)
The .50cal machine gun is mounted in the rear pedestal, and the drivers' foul weather hoods are stowed on the turret side. The location of the rooftop machine gun on many American designs was quite inconvenient, leading crews in the Korean War to engineer their own mounts in front of the commander's cupola. Mounts in front of the cupola were later standardized and fitted. (Picture from TM 9-735 Medium Tanks M26 and M45.)
The aperture for the gunner's telescope M76G is visible in the howitzer shield above the assistant driver. (Picture from TM 9-735 Medium Tanks M26 and M45.)
The tank is seen from above; note the socket atop the gunner's periscope in front of the cupola for the .50cal machine gun, added after crew complaints. The loader's periscope can be seen to the front left of his hatch. (Picture from TM 9-735 Medium Tanks M26 and M45.)
The howitzer is secured in its external lock. The aperture for the coaxial machine gun can be seen to the howitzer's lower left. (Picture from TM 9-735 Medium Tanks M26 and M45.)
The construction of the howitzer travel lock is detailed here. (Picture from TM 9-735 Medium Tanks M26 and M45.)
In addition to the external travel lock, an internal elevation travel lock was installed on the turret ceiling. It is shown engaged on the left and stowed on the right. (Picture from TM 9-324 105-mm Howitzer M4 (Mounted in Combat Vehicles).)
The gunner's controls are diagrammed in this picture. The cable snaking up the turret wall to the upper right connected to the commander's traverse override control lever, which allowed the commander to take control of the turret traverse. To traverse the turret to the right, the gunner rotated the top of the power traverse handle to the right or rotated the manual traverse handle clockwise. Left-hand traverse involved the opposite actions. The gear shift lever was moved to the up position for powered traverse, and down for manual traverse. Elevation was accomplished by rotating the elevation handwheel clockwise, and depression counterclockwise. One revolution of the elevation handwheel accomplished 25.1 mils of elevation, and a revolution of the manual traverse handwheel provided 21.5 mils of traverse. (Picture from TM 9-735 Medium Tanks M26 and M45.)
This view of the gunner's controls reveals the location of the electric firing triggers for the howitzer and the coaxial machine gun. (Picture from TM 9-324 105-mm Howitzer M4 (Mounted in Combat Vehicles).)
A manual firing lever for the howitzer could be found beneath the breech. (Picture from TM 9-324 105-mm Howitzer M4 (Mounted in Combat Vehicles).)
The control box for the turret, firing circuits, and stabilizer was to the gunner's right rear on the turret wall. (Picture from TM 9-324 105-mm Howitzer M4 (Mounted in Combat Vehicles).)
In addition to his telescope and periscope, the gunner could also install the sightunit M29A1 for use in both direct and indirect fire. Indirect fire azimuth could be set using the azimuth scale and micrometer on the telescope adapter, and elevation was checked by using the angle of site level vial. The elbow telescope could be used in either the vertical or horizontal position, and matching lines indicated the normal position for the line of sight during direct fire. Its reticle was composed of vertical and horizontal cross lines.
The periscope M18C was similar to the M10D, except that it used a 3x telescope and and 1x optical system. (Picture from TM 9-735 Medium Tanks M26 and M45.)
The 105mm howitzer M4 featured a manual breech and fired semifixed ammunition. It could be fired electrically or by a hand firing lever. (Picture from TM 9-735 Medium Tanks M26 and M45.)
This is an exploded view of the breech ring with the breechblock absent. (Picture from TM 9-324 105-mm Howitzer M4 (Mounted in Combat Vehicles).)
The M45 was equipped with an elevation stabilizer similar to that found in the medium tank M4. The cylinder and piston are shown here. (Picture from TM 9-735 Medium Tanks M26 and M45.)
This tank lacks a canvas cover over the howitzer mount, so the bulk of the howitzer shield can be seen. These tanks are crossing the Kumho River on their way to the Naktong River. (Picture taken 18 Sep 1950; available from the U.S. Army Media Front Page.)
