The 10 Most Outrageous Military Designs from WWII

Countless weapons were designed and deployed during the Second World War. While we constantly hear about the more successful ones, like radar or the jet engine, we often forget about the ones that utterly failed to make any impact on the battlefield.

From lethally disgusting stink bombs to unrealistic super cannons to some of the worst tank designs in history, here are the most bizarre weapon designs attempted—and sometimes even put into action—during the Second World War.

Related: Top 10 Crazy World War II Food Substitutes

10 The A13 Mk III Covenanter

Also known as the Cruiser Tank Mk III, the A13 Mk III Covenanter has often been referred to as the worst tank the British ever put into production, and for good reason. Developed just on the brink of the Second World War in 1939, it was intended to replace its predecessor, the Cruiser Mk IV. However, a series of fundamental design flaws ensured that it never truly did so. Its most glaring issue was the oversized engine, which left no space for a cooling radiator in the engine compartment and led to frequent overheating in both the engine and crew compartments.

Despite these major problems, the Covenanter entered production in 1939, with the first models delivered in 1940, even though it was clear that the tank could be used only for training and home defense. Several attempts were made to address the cooling and ventilation issues, but none were entirely successful. By 1941, the Covenanter was rendered unsuitable for combat, especially in the high-temperature desert conditions of North Africa.^[1]

9 Dummy Paratroopers

Deception was a big part of the Allied plan for the Normandy invasion, also known as the D-Day landings. The Rupert dummy paratroopers were an essential part of that, and they’re exactly what they sound like. Made with burlap and sand, they were dummies airdropped alongside real soldiers across the front. Each paratrooper was under three feet tall, though they appeared larger in the air.

Clad in paratrooper uniforms with helmets and boots, these dummies were rigged to explode upon landing to erase any proof of their existence. Their mission was to divert and distract German forces, and they were quite successful at it. Declassified testing videos from May 1943 showed that they appeared imposing from the ground, like real soldiers.

To make them more convincing, the Ruperts were airdropped alongside real British paratroopers, complete with simulated gunfire sounds and the smell of exploded shells.^[2]

8 The V3 Super Cannon

The Nazis were equipped with some of the most advanced weaponry of the time. However, none were as ambitious as the Vergeltungswaffe 3—commonly known as the V3 super cannon. It was mainly designed to bombard London from across the English Channel, using a network of massive, smoothbore barrels nestled in underground tunnels in the Pas-de-Calais region of France. Measuring up to 130 meters (426 feet) in length, these barrels were designed to fire shells at extremely high speeds for that time.

The V3 could be traced back to the First World War and the German Kaiser Wilhelm guns, which had previously bombarded Paris from a distance of about 75 miles (121 km). The gun’s construction was carried out in a hidden underground complex near Mimoyecques, where over five thousand engineers and laborers, including Russian POWs, worked on its development.

As it turned out, the V3S suffered from many technical challenges, including issues synchronizing the multiple charges used to accelerate the projectile, as well as the projectile’s general instability. Despite the resources invested in its design and construction, the super cannon never realized its potential. By the time it was nearing completion, the Allies had obtained information about the project. It began air raids to halt its progress.^[3]

7 Bat Bombs

The idea of bats as bombs originated in 1942, when a Pennsylvania dentist, Lytle S. Adams, proposed it to President Franklin D. Roosevelt. Known as Project X-Ray, the concept involved attaching small incendiary bombs to bats, which would then be released from airplanes over Japanese cities. The bats would seek refuge in buildings, and when the attached bombs detonated, they would ignite fires due to the flammable materials widely used in Japanese construction at the time.

The prototype used a unique adhesive that dissolved rapidly, allowing the bombs to detach effectively in midair. Scientists from the University of California, Berkeley, were enlisted to design and test the weapon, and the US government spent more than $2 million on the project.

Despite these massive investments, however, the project never succeeded. The primary challenges involved deployment timing, control, and the bats’ unpredictable behavior during testing, along with technical issues with the bomb’s mechanism.^[4]

6 Project Habakkuk

Project Habakkuk was a secret British military project to construct an enormous floating aircraft carrier made of ice and wood pulp to counter the German U-boat threat in the Atlantic, where conventional aircraft carriers and long-range bombers were impractical. The plan was approved in 1942 by the British government, led by Winston Churchill, and the concept was the brainchild of scientist Geoffrey Pyke.

At 2,000 feet (610 m) long and 200 feet (61 m) wide, capable of carrying 300 aircraft, the proposed carrier would have been the largest ship in the world, built with a blend of wood pulp and ice known as pykrete as its primary construction material. A prototype was built and tested on Lake Patricia in Canada, though the project was never completed due to several challenges. Most importantly, it required a massive refrigeration system to keep the material from melting.

The introduction of long-range patrol planes and improved centimetric radar technology by 1943 made the project ultimately obsolete, as they were capable of tracking U-boats in the Atlantic at a fraction of the cost.^[5]

5 The Bob Semple Tank

Often called the “worst tank in history,” the Bob Semple tank was designed by New Zealand’s Minister of Public Works, Robert Semple, during the Second World War. The decision was taken after considering the fact that New Zealand and Australia did not produce any homegrown armored fighting vehicles and were unable to secure supplies from abroad due to the war.

Towering at a comical height of 12 feet (3.7 m), these tanks were, to say the least, not ideal. They were top-heavy, which made off-road movement challenging, and firing on the move was nearly impossible due to excessive vibrations from the six-cylinder diesel engine. On top of that, the tank lacked a turret hatch—a major design flaw in the event of an emergency.

Despite its impracticality, several models of the Bob Semple tank were built in 1941. While the New Zealand Army intended to use some of them for beach defense, Japan’s changing position in the Pacific rendered them unnecessary. The tank was never mass-produced or used in combat.^[6]

4 Anti-Tank Dogs

Anti-tank dogs were deployed by Soviet forces on the Eastern Front, mostly as a last-ditch attempt to stop the seemingly unstoppable advance of German armored divisions. Initially, the dogs were trained to carry explosives to enemy tanks, which their handlers would detonate from a distance. This method soon proved impractical, as the dogs often failed to release the bombs under moving tanks. The Soviets later adopted a more extreme approach. They strapped the explosives directly to the dogs, with the expectation that they would run under enemy tanks and trigger the detonation.

In practice, the anti-tank dog program never worked as intended. When they were first deployed around 1941, the dogs often refused to approach moving tanks on the battlefield because they had been trained on stationary vehicles. More often than not, some of the dogs would turn around and run back toward Soviet trenches, endangering their own soldiers. Their use was significantly reduced by 1942, and the program officially ended in 1966 after only limited success on the battlefield.^[7]

3 The Panjandrum

The Panjandrum was an experimental weapon designed by the British to breach the formidable Atlantic Wall, a German coastal defense system running from Norway to Spain. It was supposed to be constructed with two massive wheels joined by a hollow tube filled with explosives. The goal was to launch the Panjandrum from a landing craft onto the beach, where it would roll forward and smash through the Wall’s concrete defenses, creating openings for Allied tanks to advance. The primary aim of the conceptual weapon was to minimize casualties by avoiding direct engagement with enemy forces.

When it was finally tested, however, the Panjandrum failed to make it to the battlefield due to multiple malfunctions. Its rockets misfired, causing the wheel to spin erratically and putting the testers in danger. By the end of it, the machine disintegrated and reportedly caused the death of an officer’s dog—the only known casualty attributed to it. The project was ultimately scrapped as a failure, though its absence had little impact on the outcome of the war.^[8]

2 Exploding Rats

The Special Operations Executive was a covert British agency tasked with operations of sabotage and subversion against Axis forces across Europe. One of their more unusual proposed weapons was the exploding rat—skinned dead rats filled with plastic explosives intended for use against German infrastructure. This bizarre yet promising idea was developed in 1941, as Britain sought innovative ways to hinder advancing German forces.

The plan was to place these explosive rats among coal supplies used by the Germans for their boilers, hoping they would be unknowingly shoveled into fires. The intense heat would then ignite the explosives, potentially causing damage to equipment, facilities, or transport systems.

However, the plan failed early on when the first shipment of these devices was intercepted by German forces. Although never successfully deployed, the concept demonstrates the lengths to which wartime intelligence agencies were willing to go to pursue unconventional sabotage methods.^[9]

1 The “Who, Me?” Stink Bomb

The “Who, Me?” bomb was a highly unconventional weapon developed by the British Special Operations Executive and the American Office of Strategic Services. Rather than causing physical destruction, it was intended to disrupt enemy forces psychologically. The key ingredient was skatole, a compound known for its strong fecal odor, which could produce an overwhelming and unpleasant smell.

The bomb was designed for use in enclosed or crowded spaces, such as meeting rooms, where the sudden appearance of a powerful odor could create confusion or discomfort. The designers believed that such an effect might distract personnel or disrupt operations, even if only temporarily.

Despite its successful development, the “Who, Me?” bomb was not widely used in combat, largely because of its unpredictable nature and the risk of harming friendly personnel. It remains one of the more unusual examples of psychological warfare explored during the conflict.^[10]