All of that looks good on paper – but getting it to work in the real world is a lot more difficult. Flying wings have proved to be a headache for aircraft designers stretching back almost to the time of the Wright Brothers. All of which makes the achievements of the German Horten brothers so impressive.
The Hortens – Walter and Reimar – began designing aircraft in the early 1930s, while Germany was officially banned from having an air force under the constraints of the Treaty of Versailles following World War One. The brothers had joined sporting air clubs, set up as a way to get around such restrictions, and which were a foundation for what could become Nazi Germany’s air force, the Luftwaffe.
Many of the amateur aviators who would later become Luftwaffe pilots cut their teeth flying various gliders and ‘sailplanes’, unpowered aircraft which taught them the rudiments of flying. The Horten brothers combined flying with designing aircraft as well – turning the family’s lounge-room into a workshop to work on new designs, according to the aviation website Aerostories.
The pair followed some of the esoteric ideas of unconventional aircraft designer Alexander Lippisch, who was a pioneer of delta-wing aircraft designs; another radical form that came into its own once jet engines had been developed. The Hortens developed their flying wing approach with increasingly effective results, ending in their Horten Ho IV glider, in which the pilot lay prone in the aircraft, which meant the cockpit canopy didn’t jut so far out from the fuselage and create aerodynamic drag.
By the time the Ho IV glider was being tested, Walter Horten had already served as a Luftwaffe fighter pilot during the Battle of Britain. Russ Lee, a curator at the Smithsonian Air and Space Museum in Washington DC, says this was a turning point. “The Germans, of course, lost the Battle of Britain, and Walter realised that Germany needed a new kind of fighter aircraft. And an all-wing aircraft might make that good new fighter.”
At the same time, the head of the Luftwaffe, Hermann Goring, had requested designs in a project called ‘3x1000’ – aircraft that would be able to carry a 1,000kg (2,200lb) bombload 1,000 miles (1,600 kilometres) at 1,000km/h (625mph). That led the Hortens to develop what would eventually become the Ho 229 prototypes. The first of the three prototypes was an unpowered glider, built to test the aerodynamic design. The second added jet engines, and flew successfully on 2 February 1945, though it crashed after engine failure on another test flight a few weeks later, killing its test pilot. But the tests proved, says Lee, that the aircraft could take off, cruise and land, and the aircraft’s basic design was sound.