Horten HO-229: The Mother of all Modern Stealth Aircrafts
– Bhagavan Hindustani
The Genesis:
In August 1943, one of the two German brothers who were working on different types of flying wing designs since the 1930s came up with a radically new idea for a flying wing which they thought can change the dynamics of the Second World War. Reimar and Walter Horten were those brothers who proposed the idea of designing and making a “flying wing” design, which was unheard of at that time.
After proposing the idea of the flying wing aircraft, the duo received half a million Reich marks (German currency at that time) to start work on the aircraft from the then German Air Force (Luftwaffe) chief Hermann Göring. The idea of originally designing the H IX (first prototype) came from Walter Horten who was serving as a fighter pilot during the War of Britain (1940). The original idea came from design deficiencies of Germany’s most advanced fighter then, the Messerschmitt Bf 109. The need for an advanced fighter which is superior in performance to Bf 109 made Walter come up with the idea of H IX.
Design:
Reimar who was a designer, started working on an all wing design right from the 30s and he thought that the new fighter required a powerful jet engine to reach its expected performance. He started working on different wing designs by constructing interim models even though he was denied access to advanced wind tunnels because of the lack of an advanced degree and education. He built Hv b and Hv c to evaluate the wing design with twin engines. Later Junker 004 engines, which powered other German aircrafts such as Me 262, Arado Ar 34 and He 162 was proposed to be fitted on to the wing.
Source : Alpha-Defense
In the beginning of 1943, Göring complained about the large variety (about 17) of aircrafts that Germany was using at that time which caused a lot of issues with cross compatibility as no two designs were similar and were constrained with mediocre performance. He wanted an aircraft which satisfied all his needs such as long range, more payload capacity and speed. Walter then proposed his design to which Göring agreed immediately and issued a contract to the brothers with a condition that the aircraft should fly in 3 months.
Construction:
Reimar gave roman numerals to all of his prototypes and H IX became the first German air force prototype and came to be known as Ho 229. Each prototype was given a “v” with 1, 2 and 3 following ‘V’ (versuch). In September 1944, the jets went into mass production in Gotha. Wood was a weird choice for this aircraft specially in this scenario. Though the first plan was to use aluminium as a material for the aircraft, Reimar’s ability to design the aircraft using wood and steel tubes and his expertise to work with wood made him believe that aluminium was not at all a contender for the aircraft. As the development went on, the Ho 229 was benchmarked against the mainstay of German air force, the Me 262. According to Reimar, the heavier wing in Me 262 required the aircraft to take off from a longer run way and made it unable to land on unprepared runways which the Ho 229 was able to do.
Testing:
Successful tests led to the construction of the Horten 229 V2 but because of the lack of communication with engine makers, the fighter got delayed. The initial plan was to use BMW’s 003 engine but later on, the Junkers 004 was selected as the main power plant. The aircraft weighed about 9 tons with all the fuel which made it a medium class aircraft of that time, similar to Heinkel He 111.During the final test flight, the aircraft crashed because of engine failure, killing the veteran test pilot Lt. Erwin Ziller. The test flights showed that the maximum speed the aircraft attained was 977 kmph though this was never recorded officially. The Horten brothers wanted to arm the aircrafts with canons before which the war inevitably ended.
After War Scenario:
On April 1945 in Friedrichsroda Germany, the US army found the prototypes of Ho 229 from v3 through v6 series. V4 and V5 were designed as single seat night fighters and v6 as a twin seat fighter. These unfinished prototypes were shipped to US as part of a research programme. In mid 1980s when Reimar was interviewed, he claimed that the main reason for selecting wood as the main material was that it didn’t reflect any radar waves, essentially making it a “STEALTH” aircraft. Later on at the public unveiling of Northrop’s B-2 bomber in November of 1988 made the public speculate that Horten brothers have built the first ever ‘STEALTH’ aircraft.
Mary Baker Engen Restoration Hangar at the Steven F. Udvar-Hazy Centre which was opened on 15 March 2011 had the H IX V3 outer wing panels for public exhibition. National Geographic Channel also telecasted a documentary where Engineers from Northrop reconstructed the unfinished prototype and tested the claims of its design engineers about the STEALTH and speed capabilities. The results astonished the engineers and scientists that the aircraft was actually 20% stealthier than other vintage aircrafts and could have changed the scenario of the world war with the types of tactics German air force used at that point of time.
Influence on Modern day Aircrafts:
This particular continuous wing like design has influenced the modern day stealth bombers (3) and stealth UCAVs so much that US designed and operated the B-2 SPIRIT which was designed on the basis of this aircraft and most of the modern day fighters too follow the same trend of continuous design to reduce the RCS (Radar Cross Section) of an aircraft. In fact our own Indian UCAV Ghatak will be similar to this continuous wing design along with advanced RAM coatings. The Horten brothers knowingly or unknowingly laid the foundation for the modern day air craft design back in the 40s. World’s first fifth generation aircraft the F-22 was loosely based on the continuous wing like design (3) similar to that of Ho-229 in order to reduce the RCS. So the conclusion is that the Ho-229 was the precursor of today’s stealth aircrafts and was far ahead of its time in one way or another.