Ever Wonder Why These 2 WWII Planes Stuck Together?

In early 1944, a British reconnaissance Spitfire pilot flying over northern France noticed something unusual: two German Heinkel 111 bombers appeared to be joined together as one aircraft. Initially, British intelligence dismissed the sighting, thinking it might have been an optical illusion caused by two bombers flying in close formation. Some even suggested that the pilot’s imagination had run wild. However, the pilot had actually spotted a Heinkel 111Z on a training mission. A few weeks later, the existence of this strange aircraft was confirmed when an RAF Mosquito shot down one, along with two Gotha gliders it was towing.

Heinkel 111Z: The Dual-Bomber Solution to Heavy Glider Transport

The Heinkel 111Z was developed quickly in 1941. The goal was to create a plane powerful enough to tow the Me321 heavy cargo glider, which had just been introduced. This glider, named “Gigant” or “Giant,” was originally intended for Operation Sea Lion, the planned invasion of Britain in September 1940. However, after the Battle of Britain ended on October 31, 1940, and the British Royal Air Force (RAF) maintained control of the skies, the invasion plan was abandoned.

Despite this, German High Command saw value in continuing the project. The Me321 could be useful for transporting troops and supplies across the vast Russian front. The Me321 was indeed massive, with a wingspan of 180 feet (55 meters). It could carry up to 130 soldiers or about 23 tons of equipment and supplies—more than six times the capacity of the standard German transport plane, the Junkers Ju52. The Me321 was unique in that it could carry armored vehicles, something the Ju52 could not manage. Because of this, the Me321 was seen primarily as a transport aircraft rather than a glider for assault operations.

However, a significant issue arose: getting the Me321 off the ground was a major challenge. Even using three powerful Me110C twin-engine fighter bombers to tow it into the air proved to be too risky and complicated. To solve this problem, the aircraft manufacturer Heinkel came up with a bold but practical solution. They joined two of their He 111 twin-engine medium bombers together, adding a fifth engine at the connection point. This combination of engines provided extra power, making it possible to lift the heavy glider.

Operational Challenges and Limited Deployment of the Heinkel 111Z

The development of this hybrid aircraft was swift and went relatively smoothly, and by 1942, it was ready for service. Despite the five engines generating a combined power of over 6,500 horsepower—more than the modern US C-130 Hercules cargo plane, which has a maximum of 4,700 horsepower—the Heinkel 111Z was still underpowered when towing a fully loaded Me321 Gigant. To help with takeoff, they added underwing-mounted booster units that could be jettisoned after takeoff. These boosters would then parachute back to the ground for reuse. The Heinkel 111Z had a crew of seven, with the main pilot, chief mechanic, radio operator, navigator, and gunner all located in the left fuselage, while the right fuselage housed the co-pilot, second mechanic, and another gunner.

Surprisingly, the Heinkel 111Z was well-regarded by its crews. It had an impressive range of over 1,200 miles (about 1,900 kilometers), which could be extended by using fuel drop tanks, allowing the plane to stay in the air for up to 10 hours. However, the aircraft had a significant flaw: its slow towing speed of just over 130 miles per hour (209 kilometers per hour). This was less than a third of the speed of a US P-51 Mustang fighter, making the Heinkel 111Z particularly vulnerable to attacks from Allied fighters. Because of this vulnerability, the aircraft was kept away from the front lines during its service.

In 1942, there were discussions about using the Heinkel 111Z in an invasion of Malta or to help relieve the German Sixth Army trapped in Stalingrad. However, neither mission was carried out due to the aircraft’s susceptibility to enemy fighters. Only twelve Heinkel 111Zs were ever produced, and they were primarily used to support a fleet of around 200 Me321 heavy gliders.

Abandoned Ambitions and the Legacy of the Heinkel 111Z

The German Air Force had high hopes for this variant of the Heinkel bomber and even planned to create a heavy bomber version, as well as a high-altitude reconnaissance version. By 1944, the bomber version, known as the Z2, seemed like a promising idea, especially since the Luftwaffe’s latest heavy bomber, the Heinkel He-177 Griffin, was plagued by engine issues that often caused it to catch fire during flights.

The proposed Z2 would have featured a 20-millimeter cannon mounted on top of the fuselage, along with the capability to carry the new Henschel HS293 anti-ship radio-controlled guided missiles. The Z3 reconnaissance version was designed to have such a long range that, in theory, it could have reached New York from German-controlled airbases in France. However, these plans were abandoned later in 1944 when the German leader decided to stop all bomber production and focus on producing more fighter planes. This was a last-ditch effort to counter the massive Allied air raids that were devastating German industrial sites.

Unfortunately, none of the Heinkel 111Z aircraft survived the war. However, the concept of a twin aircraft lived on when the United States developed the North American F-82, a twin Mustang aircraft. A total of 262 of these radar-equipped planes were produced, and they served with the United States Air Force from 1946 to 1953. The Me321 also saw further development, evolving into the Me323, which had six engines and no longer required tug planes for takeoff.