The Ho 229 might have been a formidable adversary over the skies of World War II, but in truth the plane was far from ready for mass production by the war’s end. While it seems a stretch to claim that the Ho 229 was intended to be a stealth aircraft, there’s little doubt that it pioneered design features that continue to see use in low-observable aircraft today.
Northrop Grumman revealed this year it is developing a second flying wing stealth bomber, the B-21 Raider, to succeed its B-2 Spirit. However, it was a pair of German brothers in the service of Nazi Germany that developed the first jet-powered flying wing—which has been dubbed, debatably, “Hitler’s stealth fighter.”
But maximizing speed and range, not stealth, was the primary motivation behind the bat-shaped jet plane.
(This first appeared in 2016.)
Walter Horten was an ace fighter pilot in the German Luftwaffe, having scored seven kills flying as wingman of the legendary Adolf Galland during the Battle of Britain. His brother Reimar was an airplane designer lacking a formal aeronautical education. In their youth, the pair had designed a series of innovative tail-less manned gliders.
In 1943, Luftwaffe chief Herman Goering laid out the so-called 3x1000 specification for a plane that could fly one thousand kilometers an hour carrying one thousand kilograms of bombs with fuel enough to travel one thousand kilometers and back—while still retaining a third of the fuel supply for use in combat. Such an airplane could strike targets in Britain while outrunning any fighters sent to intercept it.
Clearly, the new turbojet engines Germany had developed would be required for an airplane to attain such high speeds. But jet engines burned through their fuel very quickly, making raids on more distant targets impossible. The Horten brothers’ idea was to use a flying wing design—a tail-less plane so aerodynamically clean it generated almost no drag at all. Such an airframe would require less engine power to attain higher speeds, and therefore consume less fuel.
Flying wing designs were not an entirely new idea and had been used before in both gliders and powered aircraft. During World War II, Northrop developed its own high-performing XB-35 flying wing bomber for the U.S. military, though it failed to enter mass production. Despite the aerodynamic advantages, the lack of a tail tended to make fly wing aircraft prone to uncontrolled yaws and stalls.
The Horten brothers were given the go-ahead to pursue the concept in August 1943. They first built an unpowered glider known as the H.IX V1. The V1 had long, thin swept wings made of plywood in order to save weight. These “bell-shaped” wings compensated for yawing problem. Lacking a rudder or ailerons, the H.IX relied upon “elevons” (combinations of ailerons and elevators) and two sets of spoilers for control. The elevons could be moved differentially to induce roll, or together in the same direction to change pitch, while the spoilers were used to induce yaw.
Following successful tests of the V1 glider at Oranienberg on March 1944, the subsequent V2 prototype was mounted with two Jumo 004B turbojet engines nestled to either side of a cockpit pod made of welded steel tubing. It also featured a primitive ejection seat and a drogue chute deployed while landing, while redesigned tricycle landing gear was installed to enable the plane to carry heavier loads.
The first test flight occurred on February 2, 1945. The manta-shaped jet exhibited smooth handling and good stall resistance. The prototype even reportedly beat an Me 262 jet fighter, equipped with the same Jumo 004 engines, in a mock dogfight.
But the testing process was cut short on February 18 when one of the V2’s jet engines caught fire and stopped mid-flight. Test pilot Erwin Ziller performed a number of turns and dives in an effort to restart the engine, before apparently passing out from the fumes and spiraling his plane into the ground, mortally wounding him.
Regardless, Goering had already approved the production of forty flying wings, to be undertaken by the Gotha company, which mostly produced trainers and military gliders during World War II. The production planes were designated Ho 229s or Go 229s.
Because of the Ho 229’s great speed—it was believed the production version would be able to attain 975 kilometer per hours—it was repurposed to serve as a fighter with a planned armament of two heavy Mark 103 thirty-millimeter cannons. Construction of four new prototypes—numbered V3 throuh V6— was initiated, two of which would have been two-seat night fighters.
However, the Ho 229 never made it off the ground. When American troops of VIII Corps rolled into the factory at Friedrichroda, Germany in April 1945, they found just the cockpit sections of the prototypes in various stages of development. A single pair of corresponding wings was found 75 miles away. The most complete of the four, the V3 prototype, was shipped back to the United States for study along with the wings, and can today be seen under restoration at the Udvar-Hazy Center of the United States Air and Space Museum in Chantilly, Virginia.