The Horten Ho 229 (often erroneously called Gotha Go 229)

If its fuselage, tail, and engine nacelles contribute nothing to an aircraft's lift, why not get rid of them?

Designers pursued the all-wing dream from the first decade of powered flight, notably Jack Northrop in the U.S. and the Horten brothers in Germany. Reimar and Walter Horten were a step ahead, testing an all-wing sailplane in 1933, a twin-engined pusher in 1937, and a turbojet fighter-bomber in 1944. When the war ended, Reimar was working on a six-engine 'Amerika Bomber' to carry a hypothetical atomic bomb to New York City.

Postwar, the western Allies dismissed their work, though the British toyed with a transport version of the Amerika Bomber. Walter stayed in Germany and eventually rejoined the Luftwaffe; Reimar went to Argentina and worked for the Peron government.

Meanwhile, Jack Northrop was still trying to build a successful all-wing turbojet bomber in the 1950s. That he never hired the Hortens, who as German engineers were recruited for the U.S. space program, may have been one of history's great missed opportunities.

In the end, all that came from their work was a dozen aircraft whose beauty still astonishes. This is especially true of the Ho 229 fighter-bomber, a bat like warplane that would not look out of place at a 21st-century air show--or combat airfield.

In the 1930's and 1940's in Germany, the Horten Brothers, Walter and Reimar, built a succession of flying wing designs which were quite advanced, and on the cutting edge for their day. Their "Ho" series is as follows:

Ho I - 1931 - a flying-wing sailplane.

Ho II - 1934 - initially a glider, it fitted with a pusher propeller in 1935. Looked very like Northrop's flying wings.

Ho III - 1938 - a metal-frame glider, later fitted with a folding-blade (folded while gliding) propeller for powered flight.

Ho IV - 1941 - a high-aspect-ratio glider (looking very like a modern sailplane, but without a long tail or nose).

Ho V - 1937-42 - first Horten plane designed to be powered, built partially from plastics, and powered by two pusher propellers.

Ho VI "flying parabola" - an extremely-high-aspect-ratio test- only glider. (After the war, the Ho VI was shipped to Northrop for analysis).

Ho VII - 1945 - considered the most flyable of the powered Ho series by the Horten Brothers, it was built as a flying-wing trainer. (Only one was built and tested, and 18 more were ordered, but the war ended before more than one additional Ho VII could be even partially completed.

Ho VIII - 1945 - a 158-food wingspan, 6-engine plane built as a transport. Never built. However, this design was "reborn" in the 1950's when Reimar Horten built a flying-wing plane for Argentina's Institute Aerotecnico, which flew on December 9, 1960 -- the project was shelved thereafter due to technical problems.

Ho IX - 1944 - the first combat-intended Horten design, a jet powered (Junkers Jumo 004B's), with metal frame and plywood exterior (due to wartime shortages). First flew in January 1945, but never in combat. When the Allies overran the factory, the almost-completed Ho IX V3 (third in the series - this plane was also known as the "Gotha Go 229") was shipped back to the Air and Space Museum.

Four aircraft of the Ho IX type were started, designated V.1 to V.4. The V.1 and V.2 were built at Göttigen, designed to carry two BMW 003 jet engines.

V.2 was built with two Juno 004 (jet) engines and had two hours flying before crashing during a single-engine landing. The test pilot, Ziller, apparently landed short after misjudging his approach.

V.3 was built by Gotha at Friedrichsrodal as a prototype of the senior production version.

V.4 was designed to be a two-man night fighter, with a stretched nose in the fuselage to accommodate the second crewman.

The Horten Ho 229 (often erroneously called Gotha Go 229 due to the identity of the chosen manufacturer of the aircraft) was a late-World War II flying wing fighter aircraft, designed by the Horten brothers and built by the Gothaer Waggonfabrik. It was a personal favourite of Reichsmarschall Hermann Göring, and was the only plane to be able to meet his performance requirements.

In the 1930s the Horten brothers had become interested in the all-wing design as a method of improving the performance of gliders. The all-wing layout removes any "unneeded" surfaces and –in theory at least– leads to the lowest possible drag. For a glider low drag is very important, with a more conventional layout you have to go to extremes to reduce drag and you will end up with long and more fragile wings. If you can get the same performance with a wing-only configuration, you end up with a similarly performing glider with wings that are shorter and thus sturdier.

Years later, in 1943 Reichsmarschall Göring issued a request for design proposals to produce a bomber that was capable of carrying a 1000 kg load over 1000 km at 1000 km/h; the so called 1000/1000/1000 rule. Conventional German bombers could reach Allied command centers in England, but were suffering devastating losses, as allied fighter planes were faster than the German bombers. At the time there was simply no way to meet these goals; the new Jumo 004B jet engines could give the speed that was required, but swallowed fuel at such a rate that they would never be able to match the range requirement.

The Hortens felt that the low-drag all-wing design could meet all of the goals – by reducing the drag, cruise power could be lowered to the point where the range requirement could be met. They put forward their current private (and jealously guarded) project, the Ho IX, as the basis for the bomber. The Government Air Ministry (Reichsluftfahrtministerium) approved the Horten proposal, but ordered the addition of two 30MM cannon, as they felt the aircraft would also be useful as a fighter due to its estimated top speed being significantly higher than any allied aircraft.

Reichsmarschall Göring believed in the design and ordered the aircraft into production at Gotha as the RLM designation of Ho 229 before it had taken to the air under jet power. Flight testing of the Ho IX/Ho 229 prototypes began in December 1944, and the aircraft proved to be even better than expected. There were a number of minor handling problems but otherwise the performance was outstanding.

Gotha appeared to be somewhat upset about being ordered to build a design from two "unknowns" and made a number of changes to the design, as well as offering up a number of versions for different roles. Several more prototypes, including those for a two-seat 'Nacht-Jäger' night fighter, were under construction when the Gotha plant was overrun by the American troops in April of 1945.

The Gotha factory also was building the radar-equipped Horten Ho IX, a for that time futuristic jet-engine flying wing. Using the knowledge they gathered from the construction of these now named Gotha Go 229 (the other name used for the Horten Ho IX), they made a proposal for a fighter, the Gotha P60. The P60 used nearly the same wing layout as the Go 229. The first proposal, the P60A, used a cockpit with the crew (2) in a prone position laying side-to-side.

The engines of the P60A were placed outside the wing. One on top of the central part, one under the central part. Maybe this was done for better maintenance of the engines.

The second proposal, the Gotha P60B, no longer had the prone pilots. It seems to be that Gotha needed to make a simplified cockpit. Maybe they wanted to speed up development or production. Gotha got approval to start building the P60B-prototype, but work was stopped in favor of the final proposal, the P60C.

The Ho 229 A-0 pre-production aircraft were to be powered by two Junkers Jumo 004B turbojets with 1,962 lbf (8.7 kN) thrust each. The maximum speed was estimated at an excellent 590 mph (950 km/h) at sea level and 607 mph (977 km/h) at 39,370 ft (12,000 m). Maximum ceiling was to be 52,500 ft (16,000 m), although it is unlikely this could be met. Maximum range was estimated at 1180 miles (1,900 km), and the initial climb rate was to be 4330 ft/min (22 m/s). It was to be armed with two 30 mm MK 108 cannon, and could also carry either two 500 kg bombs, or twenty-four R4M rockets.

It was the only design to come close to meeting the 1000/1000/1000 rule, and that would have remained true even for a number of years after the war. But like many of the late war German designs, the production was started far too late for the plane to have any effect. In this case none saw combat.

The majority of the Ho-229's skin was a carbon-impregnated plywood, which would absorb radar waves. This, along with its shape, would have made the Ho-229 invisible to the crude radar of the day. So it should be given credit for being the first true "Stealth Fighter". The US military initiated "Operation Paperclip" which was an effort by the U.S. Army in the last weeks of the war to capture as much advanced German weapons research as possible, and also to deny that research to advancing Russian troops. A Horton glider and the Ho-229 number V2 were secured and sent to Northrop Aviation in the United States for evaluation, who much later used a flying wing design for the B-2 "Spirit" stealth bomber. During WWII Northrop had been commissioned to develop a large wing-only long-range bomber (XB/YB-35) based on photographs of the Horton's record-setting glider from the 1930's, but their initial designs suffered controllability issues that were not resolved until after the war.

The Northrop XB-35 and YB-35 were experimental heavy bomber aircraft developed by the Northrop Corporation for the United States Army Air Forces during and shortly after World War II. The airplane used the radical and potentially very efficient flying wing design, in which the tail section and fuselage are eliminated and all payload is carried in a thick wing. Only prototype and pre-production aircraft were built , but  interestingly, the Horten brothers were helped in their bid for German government support when Northrop patents appeared in US Patent Office's "Official Gazette" on 13 May 1941, and then in the International Aeronautical journal "Interavia" on !8 November 1941.

The Northrop YB-49 was a prototype jet-powered heavy bomber aircraft developed by Northrop Corporation shortly after World War II for service with the U.S. Air Force. The YB-49 featured a flying wing design and was a jet-powered development of the earlier, piston-engined Northrop XB-35 and YB-35. The two YB-49s actually built were both converted YB-35 test aircraft.

The YB-49 never entered production, being passed over in favor of the more conventional Convair B-36 piston-driven design. Design work performed in the development of the YB-35 and YB-49 nonetheless proved to be valuable to Northrop decades later in the eventual development of the B-2 stealth bomber, which entered service in the early 1990s.

The YB-49 and its modern counterpart, the B-2 Spirit, both built by Northrop Grumman, have the same wingspan: 172.0 ft (52.4 m). Flight test data collected from the original YB-49 test flights was used in the development of the B-2 bomber.


Ho 229 and B-2 'Sprit'

The Ho-229's design employed a thoroughly modern wing shape far ahead of its time. The wing had a twist so that in level flight the wingtips (and thus, the ailerons) were parallel with the ground. The center section was twisted upwards, which deflected air in flight, and provided the majority of its lift. Because of this twist in its shape, If the pilot pulled up too suddenly, the nose would stall (or, lose lift) before the wingtips. This meant that the craft's nose would inherently dip in the beginnings of a stall causing the plane to accelerate downwards, and thus it would naturally avoid a flat spin. A flat spin is difficult to recover from, and many rookie pilots have crashed from this condition. Horten also noticed in wind-tunnel testing that in the beginnings of a stall, most airfoil cross-sections began losing lift on their front and rear edges first. Horten designed an airfoil cross-section that developed most of its lift along the centerline of the wing. Since the center line had high lift and the front and rear edges had low lift, it was called a "Bell-Shaped lift curve". The wings were also swept back at a very modern and optimum angle (his gliders from the 1930's used this sweep long before it became popular) which enhanced its stall-resistance, and also lowered its wind-resistance which helped its top speed. This made the Ho-229 easy to fly and very stall-resistant in all phases of its operation.

The only existing Ho-229 airframe to be preserved was V2, and it is located at the National Air and Space Museum (NASM) in Washington D.C. The airframe V1 crashed during testing, and several partial airframes found on the assembly line were destroyed by U.S. troops to prevent them from being captured by advancing Russian troops.

In 1944 the RLM issued a requirement for an aircraft with a range of 11000 km (6835 miles) and a bomb load of 4000 kg (8818lbs). This bomber was to be able to fly from Germany to New York City and back without refuelling. Five of Germany's top aircraft companies had submitted designs, but none of them met the range requirements for this Amerika Bomber. Their proposals were redesigned and resubmitted at the second competition, but nothing had changed. The Hortens were not invited to submit a proposal because it was thought that they were only interested in fighter aircraft.   

After the Hortens learned of these design failures, they went about designing the XVIIIA Amerika Bomber. During the Christmas 1944 holidays, Reimar and Walter Horten worked on the design specifications for their all-wing bomber. They drew up a rough draft and worked on weight calculations, allowing for fuel, crew, armaments, landing gear and bomb load. Ten variations were eventually worked out, each using a different number of existing turbojets. Several of the designs were to be powered by four or six Heinkel-Hirth He S 011jet engines, and several of the others were designed around eight BMW 003A or eight Junker Jumo 004B turbojets.

The version that the Hortens thought would work best would utilize six Jumo 004B turbojets, which were buried in the fuselage and exhausted over the rear of the aircraft. They were fed by air intakes located in the wing's leading edge. To save weight they thought of using a landing gear that could be jettisoned immediately after takeoff (with the additional help of rocket boosters) and landing on some kind of skid. The Ho XVIII A was to be built mainly of wood and held together with a special carbon based glue. As a result, the huge flying wing should go largely undetected by radar.

The Hortens were told to make a presentation for their Amerika Bomber design on 25 February 1945 in Berlin. The meeting was attended by representatives of the five aircraft companies who originally submitted ideas for the competition. No one challenged their assertion that their flying wing bomber could get the job done. A few days later the Hortens were told to report to Reichsmarshall Göring, who wanted to talk to the brothers personally about their proposed Amerika Bomber. There they were told that they were to work with the Junkers company in building the aircraft.

Several days later Reimar and Walter Horten met with the Junkers engineers, who had also invited some Messerschmitt engineers. Suddenly it seemed that the Horten's design was to be worked on by committee. The Junkers and Messerschmitt engineers were unwilling to go with the design that the Hortens had presented several days earlier. Instead, the committee wanted to place a huge vertical fin and rudder to the rear of the Ho XVIII A. Reimar Horten was angry, as this would add many more man-hours, plus it would create drag and thus reduce the range. The committee also wanted to place the engines beneath the wing, which would create additional drag and reduce the range even further. After two days of discussion, they chose a design that had huge vertical fins, with the cockpit built into the fin's leading edge. Six Jumo 004A jet engines were slung under the wing, three to a nacelle on each side. The bomb bay would be located between the two nacelles, and the tricycle landing gear would also be stored in the same area. The committee would present the final design to the RML and recommended that it be built in the former mining tunnels in the Harz Mountains.

Dissatisfied with the committee designed Ho XVIII A, Reimar Horten redesigned the flying wing Amerika Bomber. The proposed Ho XVIII B had a three man crew which sat upright in a bubble-type canopy near the apex of the wing. There were two fixed main landing gear assemblies with two He S 011 turbojets mounted to each side.

During flight, the tires would be covered by doors to help cut down on air resistance and drag, a nose wheel being considered not necessary. Overall, the aircraft would have weighed about 35 tons fully loaded. Fuel was to be stored in the wing so that no auxiliary fuel tanks would be required. It was estimated that the Ho XVIII B would have a range of 11000 km (6835 miles), a service ceiling of 16 km (52492 feet) and a round-trip endurance of 27 hours. 

It was decided that construction was to be done in two bomb-proof hangers near Kala, which had concrete roofs 5.6 meters (18.4 feet) thick. In addition, extra long runways had been constructed so the aircraft could be test flown there too. Work was supposed to start immediately, and the RLM expected the Ho XVIII B to be built by the fall of 1945, which Reimar Horten reported to be impossible. At any rate, Germany surrendered two months later before construction could begin.

Horten Ho 229 V3

In 1943 the all-wing Horten 229 promised spectacular performance and the Luftwaffe (German Air Force) chief, Hermann Göring, allocated half-a-million Reich Marks to the brothers Reimar and Walter Horten to build and fly several prototypes. Numerous technical problems beset this unique design and the only powered example crashed after several test flights but the airplane remains one of the most unusual combat aircraft tested during World War II. Horten used Roman numerals to identify his designs and he followed the German aircraft industry practice of using 'Versuch,' literally test or experiment, numbers to describe pre-production prototypes built to test and develop a new design into a production airplane. The Horten IX design became the Horten Ho 229 aircraft program after Göring granted the project official status in 1943 and the technical office of the Reichsluftfahrtministerium assigned to it the design number 229. This is also the nomenclature used in official German documents.

The idea for the Horten IX grew first in the mind of Walter Horten when he was serving in the Luftwaffe as a fighter pilot engaged in combat in 1940 during the Battle of Britain. Horten was the technical officer for Jadgeschwader (fighter squadron) 26 stationed in France. The nature of the battle and the tactics employed by the Germans spotlighted the design deficiencies of the Messerschmitt Bf 109, Germany's most advanced fighter airplane at that time. The Luftwaffe pilots had to fly across the English Channel or the North Sea to fulfill their missions of escorting German bombers and attacking British fighters, and Horten watched his unit lose many men over hostile territory at the very limit of the airplane's combat radius. Often after just a few minutes flying in combat, the Germans frequently had to turn back to their bases or run out of fuel and this lack of endurance severely limited their effectiveness. The Messerschmitt was also vulnerable because it had just a single engine. One bullet could puncture almost any part of the cooling system and when this happened, the engine could continue to function for only a few minutes before it overheated and seized up.

Walter Horten came to believe that the Luftwaffe needed a new fighter designed with performance superior to the Supermarine Spitfire, Britain's most advanced fighter. The new airplane required sufficient range to fly to England, loiter for a useful length of time and engage in combat, and then return safely to occupied Europe. He understood that only a twin-engine aircraft could give pilots a reasonable chance of returning with substantial battle damage or even the loss of one engine.

Since 1933, and interrupted only by military service, Walter and Reimar had experimented with all-wing aircraft. With Walter's help, Reimar had used his skills as a mathematician and designer to overcome many of the limitations of this exotic configuration. Walter believed that Reimar could design an all-wing fighter with significantly better combat performance than the Spitfire. The new fighter needed a powerful, robust propulsion system to give the airplane great speed but also one that could absorb damage and continue to function.

The Nazis had begun developing rocket, pulse-jet, and jet turbine configurations by 1940 and Walter's role as squadron technical officer gave him access to information about these advanced programs. He soon concluded that if his brother could design a fighter propelled by two small and powerful engines and unencumbered by a fuselage or tail, very high performance was possible.

At the end of 1940, Walter shared his thoughts on the all-wing fighter with Reimar who fully agreed with his brother's assessment and immediately set to work on the new fighter. Fiercely independent and lacking the proper intellectual credentials, Reimar worked at some distance from the mainstream German aeronautical community. At the start of his career, he was denied access to wind tunnels due to the cost but also because of his young age and lack of education, so he tested his ideas using models and piloted aircraft. By the time the war began, Reimar actually preferred to develop his ideas by building and testing full-size aircraft. The brothers had already successfully flown more than 20 aircraft by 1941 but the new jet wing would be heavier and faster than any previous Horten design. To minimize the risk of experimenting with such an advanced aircraft, Reimar built and tested several interim designs, each one moderately faster, heavier, or more advanced in some significant way than the one before it.

Reimar built the Horten Vb and Vc to evaluate the all-wing layout when powered by twin engines driving pusher propellers. He began in 1941 to consider fitting the Dietrich-Argus pulse jet motor to the Horten V but this engine had drawbacks and in the first month of 1942, Walter gave his brother dimensioned drawings and graphs that charted the performance curves of the new Junkers 004 jet turbine engine [this engine was also fitted to these NASM aircraft: Messerschmitt Me 262, Arado Ar 234, and the Heinkel He 162]. Later that year, Reimar flew a new design called the Horten VII that was similar to the Horten V but larger and equipped with more powerful reciprocating engines. The Horten VI ultra-high performance sailplane also figured into the preliminary aerodynamic design of the jet flying wing after Reimar tested this aircraft with a special center section.

Walter used his personal connections with important officials to keep the idea of the jet wing alive in the early stages of its development. General Ernst Udet, Chief of Luftwaffe Procurement and Supply and head of the Technical Office was the man who protected this idea and followed this idea for the all-wing fighter for almost a year until Udet took his own life in November 1941. At the beginning of 1943, Walter heard Göring complain that Germany was fielding 17 different types of twin-engine military airplanes with similar, and rather mediocre, performance but parts were not interchangeable between any two designs. He decreed that henceforth he would not approve for production another new twin-engine airplane unless it could carry 1,000 kg (2,210 lb) of bombs to a 'penetration depth' of 1,000 km (620 miles, penetration depth defined as 1/3 the range) at a speed of 1,000 km/h (620 mph). Asked to comment, Reimar announced that only a warplane equipped with jet engines had a chance to meet those requirements.

In August Reimar submitted a short summary of an all-wing design that came close to achieving Göring's specifications. He issued the brothers a contract, and then demanded the new aircraft fly in 3 months. Reimar responded that the first Horten IX prototype could fly in six months and Göring accepted this schedule after revealing his desperation to get the new fighter in the air with all possible speed. Reimar believed that he had boosted the Reichsmarschall's confidence in his work after he told him that his all-wing jet bomber was based on data obtained from bona fide flight tests with piloted aircraft.

Official support had now been granted to the first all-wing Horten airplane designed specifically for military applications but the jet bomber that the Horten brothers began to design was much different from the all-wing pure fighter that Walter had envisioned nearly four years earlier as the answer to the Luftwaffe's needs for a long-range interceptor. Hencefourth, the official designation for airplanes based on the Horten IX design changed to Horten Ho 229 suffixed with 'Versuch' numbers to designate the various prototypes.

All versions of the Ho 229 resembled each other in overall layout. Reimar swept each half of the wing 32 degrees in an unbroken line from the nose to the start of each wingtip where he turned the leading edge to meet the wing trailing edge in a graceful and gradually tightening curve. There was no fuselage, no vertical or horizontal tail, and with landing gear stowed (the main landing gear was fixed but the nose wheel retracted on the first prototype Ho 229 V1), the upper and lower surface of the wing stretched smooth from wingtip to wingtip, unbroken by any control surface or other protuberance. Horten mounted elevons (control surfaces that combined the actions of elevators and ailerons ) to the trailing edge and spoilers at the wingtips for controlling pitch and roll, and he installed drag rudders next to the spoilers to help control the wing about the yaw axis. He also mounted flaps and a speed brake to help slow the wing and control its rate and angle of descent. When not in use, all control surfaces either lay concealed inside the wing or trailed from its aft edge. Parasite or form drag was virtually nonexistent. The only drag this aircraft produced was the inevitable by-product of the wing's lift.

Few aircraft before the Horten 229 or after it have matched the purity and simplicity of its aerodynamic form but whether this achievement would have led to a successful and practical combat aircraft remains an open question.

Building on knowledge gained by flying the Horten V and VII, Reimar designed and built a manned glider called the Horten 229 V1 which test pilot Heinz Schiedhauer first flew 28 February 1944. This aircraft suffered several minor accidents but a number of pilots flew the wing during the following months of testing at Oranienburg and most commented favorably on its performance and handling qualities. Reimar used the experience gained with this glider to design and build the jet-propelled Ho 229 V2.

Wood is an unorthodox material from which to construct a jet aircraft and the Horten brothers preferred aluminum but in addition to the lack of metalworking skills among their team of craftspersons, several factors worked against using the metal to build their first jet-propelled wing. Reimar's calculations showed that he would need to convert much of the wing's interior volume into space for fuel if he hoped to come close to meeting Göring's requirement for a penetration depth of 1,000 km. Reimar must have lacked either the expertise or the special sealants to manufacture such a 'wet' wing from metal. Whatever the reason, he believed that an aluminum wing was unsuitable for this task. Another factor in Reimar's choice of wood is rather startling: he believed that he needed to keep the wing's radar cross-section as low as possible. "We wished", he said many years later, "to have the [Ho 229] plane that would not reflect [radar signals]", and Horten believed he could meet this requirement more easily with wood than metal. Many questions about this aspect of the Ho 229 design remain unanswered and no test data is available to document Horten's work in this area. The fragmentary information that is currently available comes entirely from anecdotal accounts that have surfaced well after World War II ended.

As they developed the 229, the Horten brothers measured the wing's performance against the Messerschmitt Me 262 jet fighter. According to Reimar and Walter, the Me 262 had a much higher wing loading than the Ho 229 and the Messerschmitt required such a long runway for take off that only a few airfields in Germany could accommodate it. The Ho 229 wing loading was considerably lower and this would have allowed it to operate from airfields with shorter runways. Reimar also believed, perhaps naively, that his wing could take off and land from a runway surfaced with grass but the Me 262 could not. If these had been true, a Ho 229 pilot would have had many more airfields from which to fly than his counterpart in the Messerschmitt jet.

Successful test flights in the Ho 229 V1 led to construction of the first powered wing, the Ho 229 V2, but poor communication with the engine manufacturers caused lengthy delays in finishing this aircraft. Horten first selected the 003 jet engine manufactured by BMW but then switched to the Junkers 004 power plants. Reimar built much of the wing center section based on the engine specifications sent by Junkers but when two motors finally arrived and Reimar's team tried to install them, they found the power plants were too large in diameter to fit the space built for them. Months passed while Horten redesigned the wing and the jet finally flew in mid-December 1944.

Full of fuel and ready to fly, the Horten Ho 229 V2 weighed about nine tons and thus it resembled a medium-sized, multi-engine bomber such as the Heinkel He 111. The Horten brothers believed that a military pilot with experience flying heavy multi-engine aircraft was required to safely fly the jet wing and Scheidhauer lacked these skills so Walter brought in veteran Luftwaffe pilot Lt. Erwin Ziller. Sources differ between two and four on the number of flights that Ziller logged but during his final test flight an engine failed and the jet wing crashed, killing Ziller.

According to an eyewitness, Ziller made three passes at an altitude of about 2,000 m (6,560 ft) so that a team from the Rechlin test center could measure his speed using a theodolite measuring instrument. Ziller then approached the airfield to land, lowered his landing grear at about 1,500 m (4,920 ft), and began to fly a wide descending spiral before crashing just beyond the airfield boundary. It was clear to those who examined the wreckage that one engine had failed but the eyewitness saw no control movements or attempt to line up with the runway and he suspected that something had incapacitated Ziller, perhaps fumes from the operating engine. Walter was convinced that the engine failure did not result in uncontrollable yaw and argued that Ziller could have shut down the functioning engine and glided to a survivable crash landing, perhaps even reached the runway and landed without damage. Walter also believed that someone might have sabotaged the airplane but whatever the cause, he remembered it was an awful event. All our work was over at this moment. The crash must have disappointed Reimar as well. Ziller's test flights seemed to indicate the potential for great speed, perhaps a maximum of 977 km/h (606 mph). Although never confirmed, such performance would have helped to answer the Luftwaffe technical experts who criticized the all-wing configuration.

At the time of Ziller's crash, the Reich Air Ministry had scheduled series production of 15-20 machines at the firm Gotha Waggonfabrik Flugzeugbau and the Klemm company had begun preparing to manufacture wing ribs and other parts when the war ended.

Horten had planned to arm the third prototype with cannons but the war ended before this airplane was finished. Unbeknownst to the Horten brothers, Gotha designers substantially altered Horten's original design when they built the V3 airframe. For example, they used a much larger nose wheel compared to the unit fitted to the V2 and Reimar speculated that the planned 1,000 kg (2,200 lb) bomb load may have influenced them but he believed that all of the alterations that they made were unnecessary.

The U.S. VIII Corps of General Patton's Third Army found the Horten 229 prototypes V3 through V6 at Friedrichsroda in April 1945. Horten had designed airframes V4 and V5 as single-seat night fighters and V6 would have become a two-seat night fighter trainer. V3 was 75 percent finished and nearest to completion of the four airframes. Army personnel removed it later and shipped it to the U.S., via the Royal Aircraft Establishment at Farnborough, England. Reports indicate the British displayed the jet during fall 1945 and eventually the incomplete center section arrived at Silver Hill (now the Paul E. Garber Facility in Suitland, Maryland ) about 1950. There is no evidence that the outer wing sections were recovered at Friedrichsroda but members of the 9th Air Force Air Disarmament Division found a pair of wings 121 km (75 miles) from this village and these might be the same pair now included with the Ho 229 V3.

Reimar and Walter Horten demonstrated that a fighter-class all-wing aircraft could successfully fly propelled by jet turbine engines but Ziller's crash and the end of the war prevented them from demonstrating the full potential of the configuration.

The wing was clearly a bold and unusual design of considerable merit, particularly if Reimar actually aimed to design a 'Stealth Bomber 'but as a tailless fighter-bomber armed with massive 30mm cannon placed wide apart in the center section, the wing would probably have been a poor gun platform and found little favor among fighter pilots.

Walter argued rather strenuously with his brother to place a vertical stabilizer on this airplane.

Like most of the so-called 'Nazi wonder weapons,' the Horten IX was an interesting concept that was poorly executed.

Nazis were close to building stealth bomber that could have changed course of history
Nazi engineers were dangerously close to building a stealth warplane shielded from radar that could have changed the outcome of World War II
The Telegraph
8 July 2009

A prototype of the Horten Ho 229 made a successful test flight just before Christmas 1944, but by then time was running out for the Nazis and they were never able to perfect the design or produce more than a handful of prototype planes.

However, an engineering team has reconstructed the bomber – albeit one that cannot fly – from blueprints.

It was designed with a greater range and speed than any plane previously built and was the first aircraft to use the stealth technology now deployed by the US in its B-2 bombers.

It has been recognised that Germany's technological expertise during the war was years ahead of the Allies, from the Panzer tanks through to the V-2 rocket.

But, by 1943, the Nazis were keen to develop new weapons as they felt the war was turning against them.

Nazi bombers were suffering badly when faced with the speed and manoeuvrability of the Spitfire.

In 1943 Luftwaffe chief Hermann Göring demanded that designers come up with a bomber that would meet his '1,000, 1,000, 1,000' requirements – one that could carry 1,000kg over 1,000km flying at 1,000km/h.

Two pilot brothers in their thirties, Reimar and Walter Horten, suggested a "flying wing" design which they were sure would meet Göring's specifications.

The centre pod was made from a welded steel tube, and was designed to be powered by a BMW 003 engine.

But the most significant innovation was Reimar Horten's idea to coat it in a mix of charcoal dust and wood glue which he believed would absorb the electromagnetic waves of radar.

They hoped that that, in conjunction with the aircraft's sculpted surfaces, would render it almost invisible to radar detectors.

This was the same method eventually used by the U.S. in its first stealth aircraft in the early 1980s, the F-117A 'Nighthawk'.

Until now, experts had always doubted claims that the Horten could actually function as a stealth aircraft.

But, using the blueprints and the only remaining prototype craft, Northrop-Grumman defence firm built a fullsize replica of a Horten Ho 229, which cost Ł154,000 and took 2,500 man-hours to construct.

The aircraft is not completely invisible to the type of radar used in the war, but it would have been stealthy enough and fast enough to reach London before Spitfires could be scrambled.

"If the Germans had had time to develop these aircraft, they could well have had an impact," Peter Murton, aviation expert from the Imperial War Museum at Duxford, in Cambridgeshire told the Daily Mail.

"In theory the flying wing was a very efficient aircraft design which minimised drag.

"It is one of the reasons that it could reach very high speeds in dive and glide and had such an incredibly long range."

The research was filmed for a documentary on the "National Geographic Channel".

Roswell and the Horten Flying Wing

Lt Col Walker, at the Air Material Command, asked his operatives in the field to discretely track down the Horten brothers and ascertain whether their radical "Flying Wing" designs - developed during WWII - might be responsible for the rash of Flying Saucer sightings in 1947.

This is a document released under the Freedom Of Information Act  




S-2 Branch
16 December 47

Subject: Horten Brothers (Flying Saucers)

To: Deputy Director of Intelligence
European Command, Frankfurt
APO 757, US Army


1. The Horten brothers, Reimar and Walter, are residing in Göttingen at present. However, both of them are traveling a great deal throughout the Bi-Zone. Walter at present is traveling in Bavaria in search of a suitable place of employment. It is believed that he may have contacted USAFE Head-quarters in Wiesbaden for possible evacuation to the United States under "Paper Clip". Reimer is presently studying advanced mathematics at the university of Bonn, and is about to obtain his doctor's degree. It is believed that when his studies are completed he intends to accept a teaching position at the Institute for Technology (Techniscbe Hochschule) in Braunschweig sometime in February or March 1948.

2. Both brothers are exceedingly peculiar and can be easily classified as eccentric and individualistic. Especially is this so of Reimar. He is the one who developed the theory of the flying wing and subsequently of all the models and aircrafts built by the brothers. Walter, on the other hand is the engineer who tried to put into practice the several somewhat fantastic ideas of his brother. The clash of personalities resulted in a continuous quarrel and friction between the two brothers. Reimar was always developing new ideas which would increase the speed of the aircraft or improve its manoeuvrability; Walter on the other hand was tearing down the fantastic ideas of his brother by practical calculations and considerations.

3. The two men worked together up to and including the "Horten VIII" a flying wing intended to be a fighter plane powered with two Hirt engines (HM-60-R) with a performance of approximately 650 horsepower each. After the "Horten VIII" was finished, one of the usual and frequent quarrels separated the two brothers temporarily. Walter went to work alone on the "Horten IX", which is a fighter plane of the flying wing design, with practically no changes from the model VIII except for the engines. Walter substituted the Hirt engines with BMW Jets of the type TL-004. The plane was made completely of plywood and was furnished with a Messerschmidt ME-109 Landing gear.

The model of this aircraft (Horten IX) was tested extensively in the supersonic wind tunnel (Mach No. 1.0) of the aero-dynamic testing institute (Aerodynamische Versuchsanstalt), located in Göttingen. The tests were conducted in the late summer of 1944 under the personal supervision of Professor Betz, chief of the institute. Betz at that time was approximately sixty years old and next to Prandtel (then seventy-eight years old), was considered to be the best man on aerodynamics in
Germany. Betz's attitude toward the flying wing is very conservative to say the least. Basically he is against the design of any flying wing. According to the official reports about the tests, air disturbances were created on the wing tips, resulting in air vacuums, which in turn would prevent the steering mechanism from functioning properly. This seems logical as, of course, neither the ailerons nor the rudders could properly accomplish their function in a partial vacuum created by air disturbances and whirls.

In spite of that, two Horten IX's were built and tried out by a test pilot, Eugen (now living in Göttingen) at Rechlin in the fall of 1944. One of the two planes, piloted by another test pilot, developed trouble with one of the jet engines while the pilot was trying to ascertain the maximum rate of climb. The right jet stopped suddenly, causing the aircraft to go into an immediate spin and subsequent crash in which the pilot was killed. Eugen, however, was more fortunate in putting the other ship through all the necessary paces without the least trouble. He maintains that the maximum speed attained was around 950 km per hour, and that there were no steering difficulties whatsoever, and that the danger of both head and tail spins was no greater that any other conventional aircraft.

After extensive tests, the Horten IX was accepted by the German Air Force as represented by Göring, who ordered immediate mass production. The first order went to Gothaer Waggon Fabrik, located in Gotha (Thuringia) in January 1945. Göring requested that ten planes be built immediately and that the entire factory was to concentrate and be converted to the production of the Horten IX. The firm in question received all the plans and designs of the ship. In spite of this explicit order, production of the Horten IX was never started. The technical manager of the firm, Berthold, immediately upon receipt of the plans, submitted a number of suggestions to improve the aircraft. It is believed that his intention was to eliminate the Horten brothers as inventors and to modify the ship to such an extent that it would be more his brain child than anybody else's. Numerous letters were exchanged from High Command of the German Air Force and Dr. Berthold, which finally were interrupted by the armistice in May 1945. When US troops occupied the town of Gotha, the designs of the Horten IX were kept in hiding and not handed over to American Military authorities. The original designs in possession of the Horten brothers were hidden in a salt mine in Salzdettfurt, but the model tested by Eugen was destroyed in April 1945. The original designs were recovered from Salzdettfurt by British authorities in the summer of 1945.

The Horten brothers, together with Dr. Betz, Eugen and Dr. Stüper (the test pilot of the aerodynamic institute in Göttingen), were invited to go to England in the late summer of 1945 where they remained for approximately ninety days. They were interrogated and questioned about their ideas and were given several problems to work on. However Reimar was very unwilling to cooperate to any extent whatsoever, unless an immediate contract was offered to him and his brother. Walter, on the other hand, not being a theoretician, was unable to comply and Reimar was sufficiently stubborn not to move a finger. Upon their return to Göttingen Walter remained in contact with British authorities and was actually paid a salary by the British between October 1945 and April 1946, as the British contemplated but never did offer him employment. Walter subsequently had a final argument with his brother and the two decided to part. Reimar then went to the university of Bonn to obtain his degree, and Walter organized an engineering office in Göttingen which served as a cover firm to keep him out of trouble with the labor authorities. Walter married Fräulein von der Gröben, an extremely intelligent woman, former chief secretary to Air Force General Udet.

In the spring of 1947 Walter Horten heard about the flying wing design in the United States by Northrop and decided to write Northrop for employment. He was answered in the summer of 1947 by a letter in which Northrop pointed out that he, himself, could not do anything to get him over to the States, but that he would welcome it very much if he could come to the United States and take up employment with the firm. He recommended that Walter should get in touch with USAFE Headquarters in Wiesbaden in order to obtain necessary clearance.

4. As can be seen from the above, most of the Hortens' work took place in Western Germany. According to our source, neither of the brothers ever had any contact with any representative of the Soviet Air Force or any other foreign power. In spite of the fact that Reimar is rather disgusted with the British for not offering him a contract, it is believed very unlikely that he has approached the Soviet authorities in order to sell out to them. The only possible link between the Horten brothers and the Soviet authorities is the fact that a complete set of plans and designs were hidden at the Gothaer Waggon Fabrik and the knowledge of this is known by Dr. Berthold and a number of other engineers. It is possible and likely that either Berthold or any of the others having knowledge of the Horten IX would have sold out to the Soviet authorities for one of a number of reasons. However, this will be checked upon in the future, and it is hoped that contact with the the Gothaer Waggon Fabrik can be established.

5. As far as the "flying saucer" is concerned, a number of people were contacted in order to verify whether or not any such design at any time was contemplated or existed in the files of any German air research institute. The people contacted included the following:

Walter Horten

Fräulein von der Gröben, former Secretary to Air Force General Udet

Günter Heinrich, former office for research of the High Command of the Air Force in Berlin

Professor Betz, former chief of Aerodynamic Institute in Göttingen

Eugen, former test pilot

All the above mentioned people contacted independently and at different times are very insistent on the fact that to their knowledge and belief no such design ever existed nor was projected by any of the German air research institutions. While they agree that such a design would be highly practical and desirable, they do not know anything about its possible realization now or in the past.

A few items  don't make sense 

First, some excerpts from: "The Horten Flying Wing in World War II: The History & Development of the Ho 229", by H. P. Dabrowski, translated from the German by David Johnson. (Schiffer Military History Vol. 47)

"In February 1945 Heinz Scheidhauer flew the Ho VII to Göttingen. Hydraulic failure prevented him from extending the aircraft's undercarriage, and he was forced to make a belly landing. The resulting damage had not been repaired when, on 7 April 1945, US troops occupied the airfield. The aircraft presumably suffered the same fate as the Ho V and was burned.

"The [Ho IX V1, RLM-Number 8-229] machine was sent to Brandis, where it was to be tested by the military and used for training purposes. It was found there by soldiers of the US 9th Armored Division at the end of the war and was later burned in a 'clearing action'.

"Construction of the Ho IX V3 was nearly complete when the Gotha Works at Friederichsroda were overrun by troops of the American 3rd Army's VII Corps on 14 April 1945. The aircraft was assigned the number T2-490 by the Americans. The aircraft's official RLM designation is uncertain, as it was referred to as the Ho 229 as well as the Go 229. Also found in the destroyed and abandoned works were several other prototypes in various stages of construction, including a two-seat version The V3 was sent to the United States by ship, along with other captured aircraft, and finally ended up in the H.H. "Hap" Arnold collection of the Air Force Technical Museum. The wing aircraft was to have been brought to flying status at Park Ridge, Illinois, but budget cuts in the late forties and early fifties brought these plans to an end. The V3 was handed over to the present-day National Air and Space Museum (NASM) in Washington D.C."

From these excerpts we see that certainly by late April or early May, 1945, the US had not just knowledge but at least semi-functional examples of the Horten flying wing.  Ii can be assumed that the US would have wanted these craft back home for study as soon as was practical.

Lieutenant General Twining's (Commander of the Army Materiel Command) 23 September 1947 letter to Brig. General Schulgen (Commanding General Army Air Forces) states:

"It is possible within the present U.S. knowledge - provided extensive detailed development is undertaken--to construct a piloted aircraft which has the general description of the object in subparagraph (e) above which would be capable of an approximate range of 700 miles at subsonic speeds".

Why only possible?  The Horten flying wing(s) had already been in US possession for two years.

Twining continues:

"Any developments in this country along the lines indicated would be extremely expensive, time consuming and at the considerable expense of current projects and therefore, if directed, should be set up independently of existing projects".

Why expensive?  The design, prototype and development work had already been completed.  Is this a dodge for more money?

Twining points out:

"Due consideration must be given the following: The possibility that these objects are of domestic origin - the product of some high security project not known to AC/AS-2 or this command".

How likely is it that the AMC was unaware of the captured Horten flying wing(s)?

Twining states that:

"This opinion was arrived at in a conference between personnel from the Air Institute of Technology, Intelligence T-2, Office, Chief of Engineering Division, and the Aircraft, Power Plant and Propeller Laboratories of Engineering Division T-3". 

How likely is it that these groups were unaware of the captured Horten flying wing(s)?

Phil Klass [SUN #26, March 1994] quotes Air Intelligence Report No. 100-203-79, 10 December 1948:

"The origin of the devices [UFOs] is not ascertainable.  There are two reasonable possibilities: 

(1) The objects are domestic [U.S.] devices.

(2) Objects are foreign, and if so, it would seem most logical to consider that they are from a Soviet source.

"The Soviets possess information on a number of German flying-wing type aircraft, such as the Gotha P60A, Junkers EF-130 long-range jet bomber and the Horten 229 twin-jet fighter, which particularly resembles some of the descriptions of unidentified flying objects".

This report was prepared by the US Air Force's Directorate of Intelligence and the Office of Naval Intelligence and more than a year has passed since Twining's letter.

How is it that these agencies believe that it is the Soviets who have the captured Horten flying wing(s) or just information when, by this time, the US has had them for at least three years?  What value would there be in pointing the finger at the Soviets and suggesting that they have aircraft far in advance of our own?

Klass contends that the USAF Directorate of Intelligence and the Office of Naval Intelligence demonstrate no knowledge of a Roswell-related crashed object/disk because there wasn't such an incident.  Yet, three years after the fact, these same offices demonstrate no knowledge of the US possession of the Horten flying wing(s).

Klass can't have it both ways - and neither can the rest of us.

If these offices were not aware of the US possession of the Horten flying wing(s) then the so-called UFO cover-up exceeded their need-to-know and began before the Roswell incident.

If these offices were aware of the US possession of the Horten flying wing(s) then why would they not acknowledge such (in a Top Secret document that took 37 years to declassify)?

   Roswell Saucer? 

   Horten Parabola in 1945,
copied by the U.S. postwar?

   1947 Parabolic disc over New Mexico
Note aircraft features, not alien












Nothing New Under the Sun.....

















In 1944 the RLM issued a requirement for an aircraft with a range of 11000 km (6835 miles) and a bomb load of 4000 kg (8818lbs). This bomber was to be able to fly from Germany to New York City and back without refuelling. Five of Germany's top aircraft companies had submitted designs, but none of them met the range requirements for this Amerika Bomber. Their proposals were redesigned and resubmitted at the second competition, but nothing had changed. The Hortens were not invited to submit a proposal because it was thought that they were only interested in fighter aircraft..  


Artwork by Kyle Scott


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During flight, the tires would be covered by doors to help cut down on air resistance and drag, a nose wheel being considered not necessary. Overall, the aircraft would have weighed about 35 tons fully loaded. Fuel was to be stored in the wing so that no auxiliary fuel tanks would be required. It was estimated that the Ho XVIII B would have a range of 11000 km (6835 miles), a service ceiling of 16 km (52492 feet) and a round-trip endurance of 27 hours.


It was decided that construction was to be done in two bomb-proof hangers near Kala, which had concrete roofs 5.6 meters (18.4 feet) thick. In addition, extra long runways had been constructed so the aircraft could be test flown there too. Work was supposed to start immediately, and the RLM expected the Ho XVIII B to be built by the fall of 1945, which Reimar Horten reported to be impossible. At any rate, Germany surrendered two months later before construction could begin.