If-10 Naval Gun

A Japanese naval gun design from the 1940s that was intended to be a large-caliber, high-velocity gun, but was ultimately not built due to the war’s end.

If-11 Military Communications System

A German military communications system design from the 1940s that was intended to be a secure, high-speed system, but was ultimately not deployed due to technical difficulties.

If-3 Fighter

A proposed Soviet fighter aircraft design from the 1930s that was ultimately not built due to technical difficulties.

If-4 Bomber

A German bomber aircraft design from the 1940s that was intended to be a long-range strategic bomber, but was never built due to the war’s end.

If-5 Tank

A British tank design from the 1940s that was intended to be a heavy tank, but was ultimately rejected due to cost and complexity.

If-6 Submarine

A Japanese submarine design from the 1940s that was intended to be a large, long-range submarine, but was never built due to material shortages.

If-7 Anti-Aircraft Gun

A German anti-aircraft gun design from the 1940s that was intended to be a high-velocity, long-range gun, but was ultimately not produced due to the war’s end.

Hv-3700

A German tank design that incorporated advanced technologies, such as a powerful diesel engine and a more sophisticated suspension system. It was intended to be a highly advanced tank, but the project was abandoned due to the rapidly worsening war situation.

Hv-3800

A proposed German tank design that was intended to be a lighter and more mobile tank. It was designed to be a faster and more agile tank than the heavier Hv-3000 series, but the project was abandoned due to resource shortages.

Hv-3900

A German tank design that focused on firepower. It was intended to be equipped with a very powerful cannon capable of penetrating the armor of virtually any Allied tank. However, the project was never completed due to the war’s end.