The Aircraft that Could Have Made History

This post is written by Will Horton, Flight’s Washington, D.C. intern.

Sunday night the National Geographic channel premiers its documentary “Hitler’s Stealth Fighter”.

Hitler? Stealth? Fighter?

Modern stealth aircraft design did not start until the 1970s, but this documentary aims to find out if Nazis Germany developed stealth techniques three decades earlier.

In the Battle of Britain during the summer of 1940, the Luftwaffe’s advantage in numbers was matched only by Britain’s use of radar technology. The Nazis knew of Britain’s radar development, albeit not how far developed it was, and needed to re-gain their advantage.

Luftwaffe Chief Hermann Göring came into contact with aircraft builders and enthusiasts Walter and Reimar Horten. The Horten brothers, as they are known, wanted to build an aircraft that could fly with the “elegant efficiency of birds”. They developed the 2-29 (also known as the HO IX), a tailless “wing flyer” that revolutionarily incorporated the engines within the fuselage, rather than have them protrude below wings.


This futuristic aircraft is described as being the “most exotic piece of machinery in Germany at the time” and having an “unearthly shape”.

With the engines buried in the fuselage, exterior surfaces blended together, and plane constructed almost entirely out of wood (possibly to prevent radar from penetrating the skin, or possibly because Germany was facing a resource shortage), it’s easy to look back on the 2-29 with hindsight and say the Horten brothers were developing a stealth fighter to subvert British radar, but we don’t know for sure.

“Were they thinking of radar?” a Northrop Grumman employee asks. Northrop, best known for highly capable and ultra-modern defence products like its B-2 stealth bomber, decided to find out.

Teaming up with documentary producer Michael Jorgensen–who was fascinated by the 2-29–engineers in Northrop’s model shop spent three months in 2008 building a full-scale model of the 2-29 to conduct the first ever radar deflection test. Of the two aircraft constructed during the war, one was never finished and the other crashed during a test flight.

At one hour with commercials, the documentary has a few repetitive moments. While the information and various interviews are excellent, it barely skims the surface of an aircraft it acknowledges could have had major consequences for the world. Those not aviation-inclined will likely find the program sufficient while others will want to know more.

The documentary follows the Northrop engineers build the model, almost entirely out of wood, true to the original. It is ironic to watch these engineers, who normally work on projects they “can’t talk about”, build a plane out of wood using primarily glue and nails to hold it together. You could be forgiven for starting the documentary mid-way and thinking it was about seventeenth-century shipbuilding.


But therein lies the fascinating part: this relatively unknown aircraft had the potential to change history. The Nazis planned to have an atomic bomb by 1946 and wanted to use it to strike America. Based on the 2-29′s design, the Horten brothers developed the 18, an aircraft that would have six jet engines across its 142-foot wingspan (a 757′s wingspan is only 124 feet). The 18 would presumably have been Germany’s Enola Gay; the documentary’s only farfetched moment is when it depicts a mushroom cloud erupting next to the Statue of Liberty.

The team finally takes the model to Northrop’s radar cross-section test range in Tejon, California. Propped up on a five-story tall pole, the model is rotated while exposed to the same type of radar used by Britain during World War II.


The results (spoiler alert!) are scary. From the time most Luftwaffe planes appeared on British radar they could reach their target in 19 minutes. The 2-29, aided by its speed and stealth, could reach its target in only 8 minutes. “It would have been a game changer,” one Northrop engineer says. The 2-29 would have permitted just 2.5 minutes to respond.

While the documentary’s conclusion that the 2-29 pre-dated modern stealth capabilities by three decades is fascinating, equally so is the insight to so-called black programs and the people who work on them. “After 28 years working in the dark, it’s nice to spend one day in the light,” one engineer says of his time working on the 2-29 model. At the classified radar base, a man who tows the 2-29 model out of its hangar says without the slightest bit of laughter, “I’ve moved a lot of stuff, but I’ve never moved a German stealth fighter.”

Presumably the “stuff” he has moved is top-secret and highly classified, the pride of the most sophisticated engineering programs in the world, the same programs that were thought to develop stealth technology.

“Hitler’s Stealth Fighter” airs Sunday, June 28, at 9 p.m. ET/PT on the National Geographic Channel in the US.


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31 Responses to The Aircraft that Could Have Made History

  1. Sven Ortmann 27 June, 2009 at 10:46 pm #

    I don’t get why you call it “2-29″ all the time.
    The aircraft is well-known among German aviation enthusiasts as Ho IX, Go 229 and less so as “8-229″.

    Nothing is known about its in-flight characteristics.

    The structure was made mostly of wood and reflected therefore much less radar energy, but that was known from other wooden aircraft of the time as well.
    The lack of reflexiveness of the material means that the shape itself was quite irrelevant.

    The use of wood structures in WW2 aircraft was more often than not a matter of saving scarce aluminum and nothing specially radar-related. See Ta 154.

    The Germans had some radar stealth, radar absorbing materials used in WW2, but to make submarine snorkels invisible to 3cm radar, not for aircraft.

    The aircraft best-suited to bomb NY were Ju390 and Me264. the Ju 390 (non-spectacular propeller-driven aircraft) came once almost into sight of NY on a flight and was not intercepted – it’s reasonable to expect that after the lull of years without attack the air defence of East Coast CONUS was likely not up to the task of intercepting a first wave even if it was comprised of slow propeller aircraft (keep in mind that NY could have been hit at night anyway; it was actually easier to navigate over water at night).

    Finally, a prototype of the Ho XVIII was not expected earlier than 46/47 and an invasion beach or London were thousand times more relevant targets than a city on a distant continent.

    The Ho IX design was actually quite short-sighted as the internal engines were poor for maintenance and didn’t allow an upgrade to HeS 11 turbojets, the next standard engine (greater diameter). Gotha had to modify the design with upper and lower external engines to make it more practical mid-term (Go P.60 A-C).
    The only really great thing about the Ho IX design was the very high expected range (much internal volume for fuel).

  2. 7K7 27 June, 2009 at 11:16 pm #

    I seem to remember also reading about the British Vulcan bomber of the 1950s being harder to detect than its contemporaries on the radar during joint military exercises.

  3. Barbara Cockburn 29 June, 2009 at 12:45 am #

    Will Horton responds:

    Thanks for your comment, Sven. As you note, there are a lot of different names for this aircraft. I chose “2-29″ because that is what the documentary’s maker, National Geographic, refers to the aircraft as.

    You note, as do I, the possibility the aircraft was constructed of wood because of a resource shortage. But I do not think that makes the aircraft’s unique shape “irrelevant”. People have always been intrigued with objects that look different from conventional ones, and just because it has to look different out of necessity should not discredit its intriguing factors.

    You certainly seem to be quite familiar with this aircraft and the time during which it was built. I hope you get a chance to watch the documentary. If so, please let us know what you think!

  4. Matt 29 June, 2009 at 8:46 am #

    Perhaps someone more aerodynamically inclined than myself and say whether this plane would be flyable. I thought most, if not all, tailless planes basically necessitated fly-by-wire and the control systems to match.

    I see a previous comment that no flight characteristics are known. Perhaps a tailless plane may not by easily flyable by man, but a canted-tail plane can be.

    Some aspects of LO could have easily been implemented in their time, such as aligning the angles of edges and ensuring there are no right angles (mostly where the tail meets the body).

    It would be an interesting and fun exercise to see what the stealthiest fighter or bomber you could get using the controls and materials of the time could be… I just gotta work on getting that masters of electrical engineering first…

  5. solomon 29 June, 2009 at 1:13 pm #

    I know this is probably silly conjecture, but I wonder how a modern uav based on this design would fair? Design and control questions be darned, I am astonished at how close this design resembles the “beast of Kandahar”!

  6. Orihara 29 June, 2009 at 3:06 pm #

    @Matt: There’s no need for FBW to fly a tailless aircraft. Northrup built a number of flying wings, starting with the N1M, and ending with the YB-49. None of them had FBW.

  7. EG 29 June, 2009 at 5:54 pm #

    Sven and Will,
    Just a few thoughts,
    The Hortens built all of their previous aircraft out of wood. Doing the HO IX out of wood did not present any new challenge to them. The lack of vertical tail along with the wooden construction seem to my thinking to explain the reduction in warning time mentioned in the program.

  8. Pat Flannery 30 June, 2009 at 1:47 am #

    Although the replica was excellently made, it is also too smooth to be the real aircraft as far as RCS testing goes. several things were deleted that would have changed the RCS, most notably the breaks in the surface caused by the ailerons, flaps, upper and lower wing spoilers, landing gear doors, and shell casing ejection chutes.
    It also shows it approaching its target in England at low altitude, when the aircraft was designed to operate at high altitude where its jet engines would be most fuel efficient (Indeed there was a full pressure suit developed for it, a photo of which is on page 213 of “Jet Planes Of The Third Reich” by Smith and Creek)
    Flying it at low altitude would have severely cut into its range. At high altitude, the pole model should have been given a nose-up attitude to replicate the angle the radar would hit it at.
    The biggest problem is what it’s supposed to do once it reaches England…because all it can do in the form the pole model portrays it is make a strafing run with its four 30mm cannons. The quite impressive max bomb load of 4,410 pounds had to be externally carried,(it had no internal bomb bay)which would also change its RCS due to both the bombs and the bomb racks that would carry them, and decrease its speed and range due to the drag.
    The argument that it’s 20% decrease in radar return combined with its speed is misleading…a more fair assessment would be to compare it to a Ar-234 “Blitz” jet bomber and compare its detectability, as it would have been flying at around the same speed as the G0-229.
    Further the “Nazi Atomic Bomb of 1946″ is pure speculation; work on explosive nuclear weapons stopped well before 1945, and though some research probably continued on a “dirty bomb” isotopic weapon afterwards, nerve gas or biological weapons were far easier to produce, and just as lethal in their effects. So if a giant flying wing set out for New York, that’s what probably have been in its bomb bay.

  9. Freddie Freelance 30 June, 2009 at 2:55 am #

    I remember watching one of those “Weird Weapons of War” shows on the History Channel that stated that one of Germany’s big problems with wooden aircraft was the fact that their glue sucked; did these engineers use historically accurate glues or modern, improved glues?

  10. AirShowFan 30 June, 2009 at 5:32 pm #

    I read in one of Bill Sweetman’s books (“Lockheed Stealth”, I think it was) that the Germans had developed a radar-absorbing glue (based on their experience making stealth sub periscopes, as the first commenter noted) that they were going to use on this airplane. The “final” airplane’s skin would be two layers of wood with one layer of this stealth glue sandwiched in between. Of course, as other commenters have noted, it probably would not make much of a difference with discontinuities in the skin and with bombs hanging off the bottom. But still, kinda cool.

    And Matt (“June 29, 8:46 AM”); Recall that it was an electrical engineer at Lockheed who wrote the computer program to calculate the radar return of a faceted shape, leading to the design of the Have Blue and F-117. So you may be well qualified to talk stealth. As for aerodynamic stability, as another commenter noted, it is possible to build a stable tail-less airplane and to fly it without computer controls. As long as the wing is swept and twisted, the outboard sections of the wing act like a horizontal stabilizer; their lift grows more quickly per increase in angle of attack (and decreases more quickly per decrease in aoa) so they naturally create an aoa-reducing moment. (As for yaw stability, I think they basically rely on the CG being pretty far forward, so the drag of the stuff near the trailing edge should keep that stuff at the back, but this is probably only barely stable). The Planes of Fame people at Chino were flying Northrop’s N-9M until recently, and that was only one in a long series of flying wings in the 1940s. The Horten brothers themselves had built many flying wings around the same time, including some gliders (one of those is at Chino as well). And there have been tons of airplanes without horizontal stabilizers, even before the X-4 and Me-163 and the French and British delta-wing jets. Dunne had a tailless biplane in 1917.

  11. Pat Flannery 30 June, 2009 at 9:01 pm #

    Freddie Freelance wrote:
    “I remember watching one of those “Weird Weapons of War” shows on the History Channel that stated that one of Germany’s big problems with wooden aircraft was the fact that their glue sucked; did these engineers use historically accurate glues or modern, improved glues?”

    The wooden aircraft that suffered from the glue problem was the Focke-Wulf Ta 154 “Moskito” multi-role aircraft.
    The company that was going to make the glue for it (Goldmann Tego-Film from their factory in Wuppertal) was destroyed in a bombing raid, and they shifted to another type glue that had a high acid content.
    This led to the aircraft being fine at the end of construction, but the acid in the glue started to rot the wooden structure within days after construction, so within a few weeks the aircraft would begin to fall apart, so the whole program was canceled.

  12. Mariana 2 July, 2009 at 5:45 am #

    Ho IX is the correct name for the aircraft in the Smithsonian’s Garber restoration facility. Gotha was slated to manufacture the aircraft so it is possible a production variant would be called Ho 229 or Go 229.

    The Ho IX flew without FBW December 1944.

    Many other novel German aircraft designs can be found here:

    Also some VFX shots of German aircraft including the Ho IX can be found here:

  13. Mariana 2 July, 2009 at 5:46 am #

    Ho IX is the correct name for the aircraft in the Smithsonian’s Garber restoration facility. Gotha was slated to manufacture the aircraft so it is possible a production variant would be called Go 229.

    The Ho IX flew without FBW December 1944.

    Many other novel German aircraft designs can be found here:

    Also some VFX shots of German aircraft including the Ho IX can be found here:

  14. Mark Wales 2 July, 2009 at 1:05 pm #

    An excellent description of the design and development of this airplane is in the book “Warplanes of the Third Reich” by William Green.

  15. alex 2 July, 2009 at 1:29 pm #

    Forgive my ignorance in this subject, but doesn’t the simple fact that the Germans never had any other prototype of this kind (LO) mean that they were not interested at all in it, in it was just a coincidence that the HO IX had such features (shape, etc) that gave him such low obervability?
    I know they were not allowed to do a lot of (if any) military research in the post-war decades, but surely at some point they would go back to the original goal (build a stealth aircraft) and research it further, and they simply never did!

  16. James 2 July, 2009 at 9:18 pm #

    I think the previous criticisms of the stealth qualities of the Ho IX are forgetting that British radar also wasnt up to much when compared to modern standards, and relied heavily on the operator’s interpretation of the blips.

    Thankfully, we will never know how successful the aircraft would have been at avoiding detection, but it is conceivable that an Ho IX with a moderate load of externally carried bombs could still have reduced the available scramble time for RAF fighters and put further pressure on an air force that was already on the verge of collapsing.

  17. john 4 July, 2009 at 10:23 am #

    @ James

    The HO IX and other highly advanced aircarft could have made a difference, if only the Hitler régime hadn’t virtually stopped aircraft development by late 1940 . The idea seemed to be that leaving Britain to “hang on”, while themselves going for a “quick” settling of business with the Soviets would lead to victory. By the time they saw they should have second thoughts, both Bomber Command and the USAAF were doing serious damage to German industry, and raids such as that on Peenemünde also delayed the V-1 (the “first cruise missile”) which could have made things difficult for the Allies after D-day. As it was, both London and Antwerp were quite badly hit.
    The Ho IX is certainly a very “interesting” aircraft, but I think we can be glad that it hardly even started flight test !

  18. Rocketist 5 July, 2009 at 9:41 pm #

    @ Will:
    The title of this article sounds rather far-fetched. In fact the Horten is probably one of the several dozen designs that might have changed the course (but in no case the result) of the battle of England (again, not of the war itself) – had they been available five years earlier, in quantity, including reliable engines, with trained crews, deployed in an intelligent manner, and fuelled. Incidentally, any of these conditions would have been hard to meet.
    In my view, the most likely hypothetical discovery that might have influenced the war would hve been that of crude oil in the North Sea.

  19. Jan 7 July, 2009 at 9:43 pm #

    several mistakes then:

    - 3 prototypes were built: Ho IX V1 and V2, plus a single Go 229 V3 ; with the Go 229 V4 and V5 2-seaters under construction and with work being started on the Go 229 V6 and V7
    - the replica is wrong: the centre section of the Ho IX / Go 229 was NOT made of wood but was a welded steel tube section
    - the wingspan of the intended Ho XVIII was not 142 ft but 137 ft 9,5 inch
    - the range of the Ho XVIII (5600 nm) would probably have been too short for a return flight to NY

  20. Barbara Cockburn 8 July, 2009 at 6:58 pm #

    Will Horton responds:

    Thanks for the additional comments, everyone!

    @EG The documentary implied the reduction in reaction time was due to the aircraft’s stealth capabilities. It did not appear on radar immediately, hence giving the plane an edge. The factors you mentioned could have contributed to its stealth capabilities.

    @Freddie Freelance Excellent question and I wondered that myself. I don’t know the answer, but I suspect that since the program did not mention the engineers re-created the glue, they used modern glue. As @AirShowFan notes in a comment below yours, the glue could have been a very important element to thwart radar detection.

    @Mariana Thanks for the clarification. I wonder why National Geographic called it the 2-29 then.

    @alex It’s possible, but based on interviews with the Horten brothers before they passed away they did intend to make a stealth aircraft.

    @Rocketist Far-fetched? The Horten 2-29 (aka IX) was not just a design–it was a prototype that flew. You mention a lot of ifs and buts and those are variables that could have changed the outcome. The concerned outcome was not just the Battle of England but the whole war i.e. if (and some readers would say that’s a big if) the aircraft could have dropped an atomic bomb.

    @Jan Not sure who your comment was directed to, but the info all came from National Geographic. I re-checked the wingspan figure and the documentary noted the 142′ wingspan was on a bigger version, so perhaps that is one of the other prototypes you referenced.

  21. Jim Avis 5 August, 2009 at 3:05 pm #

    Watched the programme last night. Hats off to the guys at Northrop Grumman for their excellent work on the model – very impressive. Less accurate work by the programme makers though. They failed to mention that the design was a natural continuation of the glider designs the Hortens had been working on in the thirties and that although it did have a smaller radar profile than contemporary aircraft the stated “20% less” didn’t state less than what – an ME 262, a Gloster Meteor, a P51? The Horten brothers never claimed they had deliberately designed a stealth fighter and I doubt that the first prototype ever did a mock air fight with the ME 262.It surely had not reached that level of development to risk such an exercise. Whilst this typified German ingenuity and the Nazi obsession with a miracle weapon to end the war, it was for them, another blind alley – too little too late.

    Would it have tipped the scales in Germany’s favour? Hardly. The die was already cast in 1944. Germany’s advances in rocket technology had little or no impact on the final outcome and whilst the V1 & 2′s did some damage to London, their overall effects were negligible. Had Germany started the war with the jet aircraft it developed by the end of the war, then matters may well have turned out differently. That said of course, it could just have spurred the Brits and the Americans to develop their own jets a little faster.

    Well done though to the model makers of Northrop Grumman and to the Horten Bros for their futuristic design.

  22. Refugio Stull 18 March, 2010 at 6:02 am #

    This morning, I was searching for the related issue but couldn’t actually make it out. Kudos to this one.

  23. Richmond Home Builders 28 June, 2010 at 9:49 am #

    Wonderful to read!

  24. j5 11 July, 2010 at 6:40 pm #

    Sorry about posting ‘anonymous’, didn’t feel to register sicne I’m just a casual visitor (nice articles btw).

    I agree with mr. Avis to some extend. This is certainly an interesting documentary that tickles the imagination and makes one Google a bit more on the topic of this flying Wing (and one wonders if it inspired later engineers in designing the Northrop B2), but it hardly seems it would’ve changed the outcome of that war.

    It might’ve been different given different circumstances or someone other than Hitler calling the military shots or if Hitler’s navy hadn’t been crippled and co-operated a bit better with the Luftwaffe or if they would’ve managed to get some ground units onto British soil on a very large scale, but I don’t see this one project as a ‘miracle weapon’ to win that war. In the end, it’s all about resources (in people, in materials, in everything), strategy and circumstances/luck. In that day and age it just wasn’t smart to take on the whole world and open up so many fronts. Today it might’ve been different (just think of current American naval and air superiority in numbers and in technology in *most* modern military conflicts, not including the guerilla wars and ‘war on terror’).


    However, what I would actually love to see is a documentary about the MBB Lampyridae aircraft developed in *post-war* Germany and particularly, why the project was halted, abandoned or cancelled just after demonstrating the technology to a group of USAF officers. Only three months later, the USA revealed the F-117.

    If you follow through some links and Google around a bit, a lot of data can still be found on this project, bud sadly there’s quite a lot of overlapping info and not much details are available as to WHY the project was halted after enormous pressure by the US to stop it (again, no info on what kind of pressure the US put on the German government to bury this project). It’s said that one prototype actually flew.

    MBB became DASA which is now the German part of EADS. Same curiosity about the maglev-project which was originally used in underground bunker construction to avoid registering the activities on Soviet seismic equipment.

    Ofcourse everyone knows about the civilian Transrapid projects (sold to China and Brazil.. why not used in Europe?)

    It does seem that quite a few post-war German secrets remain secret (or there aren’t that many), at least to the public. NG did do a documentary on supersubs that included some hints about the AIP tech used in fairly recent stealthy (non-nuclear > no heat signature and air-independent propulsion) German 212 submarines but next to nothing about their shallow waters performance.

    I’ll shut up now, it’s not my normal practice to be off-topic, I just wondered if I’m the only one who frequently misses something in those documentaries. I hope you can all forgive me for this.

  25. Big and Tall Mens Clothing 23 July, 2010 at 3:22 pm #

    Excellent job.

  26. Lorraine 21 August, 2010 at 9:37 am #

    Battle of Britain time once more, time to think of all those brave men, heroes, all of them.

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