The Curious Ideas of Yoh – Part 1 | History

Commanders!

In the 1950s, a company called H.L. Yoh submitted several ideas for new tanks and vehicle improvements to the U.S. Army. Each of their projects featured unique shapes and innovative mechanics that seemed more or less feasible to implement. Collectively, these vehicles have been dubbed Yoh tanks. While they never reached the prototype phase or gained much attention from the U.S. Army, their unusual look and original features are well worth a closer inspection.

Let’s check out some of the ideas and proposals by the H.L. Yoh company that inspired the new branch of American heavy tanks in World of Tanks, even though not all of the ideas will find their way into the game.

Gun Shield and Turret Concepts

The new gun shield incorporated many desirable factors. The primary feature consisted of the weight being concentrated aft of the trunnion, helping to balance the gun. The shield was composed of a lightweight cast core to which the gun cradle was attached, permitting the gun to recoil. The sloped front provided excellent obliquity. The turret opening was completely sealed by the unique contour that maintained a minimum gap between the shield and turret.

Functional and space saving—a reasonable concept.

Ammunition Grab Concept

The second suggestion was an ammunition hoist to help the loader grab those heavy shells.

The ammunition grab was developed in an effort to provide the simplest possible kind of assistance in lifting shells. The grab was held in the loader's left hand, leaving the right hand free to guide and control the movement of the round. All controls for the hoist and grab were incorporated in the grab itself. Squeezing the latch grips locked the grab on the shell. Pressure was released by squeezing the trigger. The grab could also be used to replenish the ready racks. When not in use, the grab could be compactly stowed near the turret roof.

While the concept may have worked for larger artillery shells, it likely wasn't faster than the traditional loading of a 90 mm round. The clamp would also have to be tight enough to prevent the round from slipping but not exert too much force that it deformed the shell casing and prevented it from being chambered.

Armored Ready Rack Concept

This method of stowing the "Ready" ammunition offered maximum safety to the crew. It eliminated the fire hazard by which 90% of tanks were lost in World War II. The device was made to prevent fragments from striking the ammunition. If a projectile entered the rack, the resulting ammunition fire would be vented out of the tank, saving crew and equipment. In addition to the protection feature, the commander could select the proper round by remote control, and the loader would receive the round in a position that would allow ease of handling.

While it is a feasible idea and similar to the revolving ready rack/semi-autoloader on the Merkava Mk. 4, the downside is that it seems to take a lot of room inside the turret.

The diagram may be understating things a little. For example, the hatch may not be strong enough to divert an ammunition explosion up through the bottleneck chimney. Still, it is an interesting example of innovation.

Automatic Loading Mechanism Concept

This proposal indicated a method of loading the gun automatically. 18 rounds of 105 mm ammunition were stowed in the mechanism located in the bustle of the turret. The commander could press a button indicating the desired type of ammunition. A tray then received the round from the storage compartment and conveyed it to the center of the gun. A pushing arm rammed the round into the chamber and waited above the breech for the gun to be fired. After recoil and shell ejection, the pusher reversed and discarded the empty casing out of the tank and came to rest in a position to receive the next round.

The bustle autoloader was very sensible and bears a resemblance to the cassette autoloaders found in modern tanks. The only difference seems to be a gravity feed to the conveyor belt.