San Diego air museum will house replica of German stealth prototype

The National Geographic Channel describes it as one of the best-kept secrets of Adolf Hitler's Third Reich.

Toward the end of World War II, a mysterious, futuristic-looking aircraft was discovered by American troops in a top-secret German facility. The prototype jet, which resembled a massive bat wing, and other advanced German aircraft were brought to the United States in the military project “Operation Seahorse.”

In the early 1960s, the prototype jet was transferred to a Smithsonian facility in Maryland that is off-limits to the public. It remains there today.

San Diego air museum will house replica of German stealth prototype

 

That's all well and good, but will they point out that this model never flew with any success, and it wasn't developed as a "stealth" craft at all? The Horten design was simply an extension of their flying wing developments which had been going on sporatically since the twenties.

The real one was captured without its wooden wings attached, heck most of the craft was wood, but not for stealth. It was wooden for purely economic reasons, they couldn't afford the strategic material to built it out of anything else. The thing was covered in a "rubberized" paint, but that was to waterproof the wood, not defeat radar. That may have been the result, but it wasn't the intent, originally.

Even the Northrop flying wings, both propeller and jet driven were "stealthy", without that being the intent. Their radar signatures were documented as nearly impossible to detect by radars of the times. And they were HUGE flying examples, made of metal, not WOOD. But stealth wasn't Jack Northrops intent either.

I wonder how "radar stealthy" the Flying Flapjack I am currently using as my avatar would have been? It was pulled from production just as the first one was completed in the "full sized" version. The original smaller prototypes were flown for years, just never scaled up until the Vought model you see. It's piston engines and huge propellers gave it an "odd" look, but I wonder how it would have performed with a couple of the existing jets of the moment? It was pretty "spacey" looked too.

 

Here's some details on the Horten 229:

Links to images of the captured Horten 229 at the National Aeronautics And Space Museum:
Virtual Aviation Museum
Virtual Aviation Museum
Virtual Aviation Museum

Unloading at Freeman Field, Seymour, Indiana:
Jackson County, Indiana, History & Picture Archive

Horten History of the Flying Wing

In 1933, Reimar Horten built his first flying wing, a one man carrying glider in his parents‘ house.
Encouraged by its success, he built the Horten II, the world’s first motor glider. By now his flying wings
were attracting so much attention that he was helped to continue his work. He built many prototypes, most
with plans for mass production. By 1944 the Peschke company had placed an order for more than 20
Horten VII flying wings, and the Klemm company placed an order for 50 Horten IIIe. Such well known
companies as Junkers, Heinkel, Messerschmidt, BMW and Focke-Wulf were submitting flying wing
designs to the Ministry of Aviation as the war was ending and Germany had achieved a leading position in
aeronautics. This is probably why airplane construction was prohibited in Germany after the war. Flying
wing development in Germany ended. Many flying wings were destroyed, some were taken to the United
States. (At the time of writing, four flying wings from the United States are being restored in Berlin.) The
United States was very interested in what had German engineers had learned from flying wings. We
suspect that this led to the decision to build the B-47 with swept back wings rather than the straight wing
of its earliest designs.

In 1948 Dr. Horten emigrated to Argentina where he was able to continue his work on flying wings. There
he supervised the construction of a couple of flying wings, including the four engine AE 38 transport which
could carry 10 tons more than 1100 nautical miles. Unfortunately, the general who supported flying wing
development was replaced by someone who ordered the transporter to be grounded. At the university he
was only allowed to teach the construction of conventional aircraft and his communication with aircraft
builders in other countries was disrupted by the censorship and opening of his mail.

In 1950 German researchers attempted to build flying wings, but without the experience and background
of Dr. Horten, they were so unsuccessful that many believed that the flying wing could not be built.

Throughout his life Dr. Horten was plagued with what he called the „studied narrow mindedness” of his
colleagues. For example, in 1943 a famous aerodynamics scientist declared, “Sweptback wing designs run
the risk of falling over one wing with loss of control over the plane” even though Horten’s airplanes had no
such problem.

More information is contained in the book: “Nurflügel, die Geschichte der Horten-Nurflügel 1933-1960”
by Reimar Horten and Peter F. Sellinger, Weishaupt-Verlag Graz ISBN 3-900310-09-2. Additionally
you can find information and pictures in the Internet: index.


History of the PUL 10

In 1987, we met Prof. Dr. Reimar Horten in Argentina. In the following years we built a number of radio
controlled models according to his construction plans. The models flew so successfully that we built a
single seat prototype. In the winter of 1989-1990, Siegfried Panek, one of the main builders of the PUL
10, worked with Dr. Horten on construction detail plans. In January 1990 we began construction of the
PUL 9 (Panek Ultra-Light 9 meter wing span) in a little village near Frankfurt. In April we took it to Italy
where Nike Aeronautica helped us to finish building it, and it made its first flight on June 22 1990.

The PUL 9 was thoroughly tested under many different flight conditions. We were highly impressed by its
easy handling and stability in the air. In 1991 we decided to build a two seater. In the winter of
1991-1992, Siegfried Panek and Reimar Horten built a wooden model which was called the PUL 10. In
February 1992, we started to build the molds out of 3-dimensional fiberglass. We used this material for the
body of this plane too. Even though the first PUL 10 turned out to be much heavier than we expected, it
demonstrated very good flying characteristics in it‘s September 1992 test flight. Satisfied with its
aerodynamics, we began construction of the second PUL 10. This second plane took more time to build
because we reworked some of the molds for later mass production. We began testing it in Italy in summer
1994 and in spring 1995 we registered it in France and continued testing at Sarrebourg airfield.

In 1995 we replaced the 2-stroke Rotax 582 with a 4-stroke Rotax 912.

In June 1995, during a flight test over France, stalls were performed with a C.G. too far aft. In one of
these stalls, the airplane went into a spin which forced the pilot to use the built-in parachute. The landing
damaged the airframe beyond repair.

But by now we had gained enough knowledge to begin construction of the third PUL 10 in fall 1995. This
PUL 10 differs from its predecessors only in equipment and engine mounts. The shape of the plane was
not changed.

We finished it in fall 1996 and received an experimental registration in Germany.

You can find current pictures of the engine mount in the Internet:
http://www.cso.net/kurri/flug/pul10.htm

The initial take-off with german registration took place on the Breitscheid airfield on May 14th 1997.
Flight tests have been without major problems ever since. One minor problem was the retractable gear
which didn`t always extend properly. Once it was even necessary to land with the gear retracted. Apart
from slight scratches underneath and a leaking radiator there weren`t any damages worth mentioning.

Because of permanent flaws in the exaust manifold and problems with the engine cooling, we were forced
to fly mainly in the local area. However, the PUL 10 was able to be flown about 50 hours. Because of
persistent engine problems we decided to change the engine. In the winter 97/98 a 90 hp BMW
motorcycle engine was installed.


Feedback

The interest in the new plane is constantly growing. Almost daily we receive letters and phone calls. Some
interested people said they had worked on flying wing development under Reimar Horten. They were
enthusiastic about the flying wings characteristics and wondered why the development had not been
continued over the past 45 years.

The rumour about the rebirth of the flying wing has spread like wildfire. Accounts of it have been published
on almost every continent.

Also the german media show more and more interest in this extraordinary project. Since its initial flight in
May 97, 6 German TV-companies have reported on the PUL 10.

A summary of the most important European press-publications and a video-tape of all TV-reports can be
ordered (price of this “info-package” on request).

Many inquiries came from America and Australia. In these countries private aviation is of great importance.
In Australia the enormous distances between cities and small settlements would make life difficult if it were
not for small private aircraft.

Some flying wing enthusiasts have visited us to see the PUL 10 in action. Some clubs such as TWITT
(“The Wing Is The Thing”) have contacted us too.

Many of the people we talked to were dissatisfied with the lack of progress in conventional airplane
design. Some are willing to wait until the flying wing becomes available before buying a plane.

One prestigious organisation, the Oskar-Ursinus-Association, awarded the constructors of the PUL 10 the
first prize for the most progressive design in 1994 and 1997.



Other possible projects for the future

With the right investment and demand, the sky is the limit. In 1992 Dr. Horten designed a four seater flying
wing with a 12 meter wing span. Normal registration of such an aircraft for mass production would be too
expensive for all but the largest companies. However, for the American market, a four seater kit is
possible.

Dr. Horten left us with the knowledge to build even bigger flying wings. He thought of a giant flying wing
capable of carrying approximately 1000 passengers, and having a weight of 1000 tons, that would fly 30
meters / 100 ft over the water in ground effect at a speed of 600 km/h / 330 knots, connecting the
continents at a fraction of the previous cost. Take off and landing would take place on the water. This
would be a definite advantage over today’s airliners with their pressurized cabins and air pollution.

Due to latest reports US plane manufacturer McDonell Douglas and NASA have taken up Prof. Hortens
idea. A flying wing for 800 passengers is planned to go on its maiden flight in 2010. The designers expect
fuel consumption to be reduced by one third.

The past seems to catch up - why hesitate any longer?

Horten PUL 10

Contact:

Dr. Barney Vincelette,
P.O. Box 141
Houston, DE 19954

http://pages.prodigy.net/jputtputt/horten history.htm

 

AAF TRANSLATION NO.525 F -TS525- RE
English Title:
COMPARISONS OF THE 8-229 AND THE GO P-GO ALL-WING AIRPLANES
German Title: GEGENÜBERSTELLUNG 8-229 GO P-60
Author: Nauber
Date Prepared: 21 February 1946
Release Date: 22 April 1946

HEADQUARTERS AIR TECHNICAL SERVICE COMMAND
WRIGHT FIELD, DAYTON, OHIO

WF-0-24 FEB 46 10M

INTELLIGENCE (T-2) HEADQUARTERS
AIR DOCUMENTS DIVISION AIR TECHNICAL SERVICE COMMAND
TRANSLATION WRIGHT FIELD, DAYTON, OHIO

SUBJECT: Translation of Captured Enemy Document
TO: Distribution Listed

1. Attached translation is forwarded for your information and retention.
2. Recipients are invited to forward copies at translations made by the for filing in Reference Library (TSRWF), Air Documents Division, Intelligence (T-2),Hq. ATSC, Wright Field, Dayton, Ohio.

DONALD L. PUTT
Colonel, Air Corps
Deputy Commanding General
Incl. Intelligence (T-2)

DISTRIBUTION:

1 Original manuscript (German) - Foreign Document
1 Master Copy - Publ. By., Technical Servo. Section (TSRTS-4)
1 Foreign Documents
1 Special Documents
1 TSRTR
1 SNOUT - Analysis Section (T-2)
1 TSILI - Liaison Section, Collection Division
1 Publ. Br., Technical Servs. Section (TSRTS-4)
2 AC/AS-2, AFBAI-1L Attn: Maj. Towle
1 N.A.C.A. 1500 New Hampshire Avenue, Washington, D.C.
2 N.A.C.A., Langley Memorial Aero Lab., Langley Field, Va.
Attn: Maj. D. R. Estman, Jr.
1 N.A.C.A., Ames Aeronautical Lab., Moffett Field, California
1 N.A.C.A., AERL, Cleveland Municipal Airport, Cleveland, Ohio
1 Library of Congress (Division of Aeronautics), Washington, D.C.
1 Institute of Aeronautical Sciences, 1505 RCA Bldg., New York, N.Y.
3 BAGR, BuAas, Gen. Representative, Centr. Dist., Wright Fld., Dayton, Ohio.
1 Society of Automotive Engineers, Aero Div., 29 W. 39th St., New York, N.Y.
1 Commanding General, AAF Center, Orlando, Florida. Attn: AAF School Library.
1 President, AAF Board, Orlando, Florida
1 AAF Scientific Advisory Group, Ch/AS, Hq AAF, Washington 25, D.C.
Attn: Dr. Von Karman
1 Chief, Naval Intelligence, OP-23 7-2, Rm. 4524, Navy Bldg., Washington, D.C.
Attn: J. H. Alberti.
2 Unit Initiating Request TSNNT, Major Smiley


INTELLIGENCE (T-2) HEADQUARTERS
AIR DOCUMENTS DIVISION No. 525 AIR TECHNICAL SERVICE COMMAND TRANSLATION WRIGHT FIELD, 21 FEBRUARY 1946
COMPARISON OF THE 8-229 AND THE GO P-60
ALL-WING AIRPLANES
By Nauber



An attempt will be made in this treatise to present a comparison of the two all-wing airplanes, the 8-229 and its further development, the Go P-60, in their most important structural and aerodynamic interpretation.

In order to evaluate the 8-229, the V-6 will be discussed since it comprises all the required installations. It must be stated at this point that, comparatively, the 8-229 will be at a disadvantage, for the V-6 underwent considerable necessary changes compared to the original design, in respect to "aerodynamic and weight deterioration."

The airplanes in question are intended to be used for:

Service as heavy pursuit ships with a crew of 1 or 2 men.
Reconnaissance ships for close or medium range sorties.

A. GENERAL STRUCTURE

8-229 Go P-60

1) Arrangement of propulsion unit


2 x TL 109.004 within the wing close to cockpit (bulges at the entrance and emergence points)


2 x TL 109.003

a) one TL jet unit each
above and below the
end of section in
center of wing or
b) in center of airplane, in the rear, below on the pressure side next to each other.

2) Crew


1 man sitting (Pressure cabin)


2 men lying down (Pressure cabin)

3) Landing gear


Arrangement of front wheel.Distribution of load: In front 45%, in the rear 55% of total weight (Bulges in the streamline required.)


Arrangement of front wheel.Distribution of Load: In front 15%, in the rear 85% of total weight.

4) Armament


4 MK(automatic cannons) 108, each barrel 90 shots or 2 MK(automatic cannons) 103 each barrel 140 shots.


4 MK(automatic cannons) 108, each barrel 170 shots or 2 MK (automatic cannons) 103, each barrel 175 shots.

5) Fuel


4 tanks in the outer wing. Altogether 2000 kg of fuel.


One tank in the center wing. In the outer wing 1 tank each: 2000 kg of fuel (In the wing center section there is space for 1000 kg more)

6) Photographic apparatus


2 RB 50/15


2 RB 50/18

7) Construction


Center wing: tubular frame work with plywood oovering. Outer wing: ribbed construction with reinforced wooden shell (Lattice grate type under construction)


Center wing: tubular framework with plywood covering. Outer wing: wooden wings of lattice grate type.

8) Take-off weight
(At equal weight of fuel)


G = 8500 kg (18,739.1 lbs) (incl. 600 kg of ballast) (1322.4 lbs)


G = 7450 kg (16,519.8 lbs)

9) Utilization of other propulsion units.


Installation of TL 003 hardly possible. Installation of TL 011 impossible.


Installation of TL 004 can easily be done. Installation TL 011 can easily be done.

B. AERODYNAMIC LAYOUT

8-229 Go P-60

1) Wing surface


F = 53 m2 (63.38 sq.yd.)


F = 46.8 m2 (55.97 sq.yd.)

2) Entire surface


Fo = 119 m2 (142.32 sq.yd.)


F = 110 m2 (131.56 sq. yd.) (at 262 Fo = 108 m2) (129.168 sq.yd)

3) Aspect ratio


b2/F = 5.2


b2/F = 3.3

4) Sweepback


j = 28


j = 45

5) Wing sections


Asymmetrical.

Standard wing sections. Ratio of maximum thickness: 17.8% (originally 15.5%)


Symmetrical.

High speed wing sections. Ratio of maximum thickness: 13%

6) Elevator and aileron


Frise-control surfaces


Internally balanced control flaps.

7) Directional control




Interceptor- control in 80% of span (planned change in construction: Control by resistance of surface sections being extended outward from the wing in direction of span;slot in outer wing)


On wing tip extendable plates perpendicular to the wing. (presupposition: circulation forces)

8) Elevator and aileron triming


Inner control surfaces in cross position to outer control surfaces by kinematic superimposition (Planned:auxiliary trim tab)


Auxiliary trim tab in the main control surface

9) landing device


Simple trailing edge flap


a) leading edge split flap
b) split flap in wing midsection

10) Safety device against tipping


a) slight warping


a) slight warping
b) setting up wing sections along the span
c) leading edge split flap (alternative:
automatic slot)

11) Position of center of gravity and displacement of center of gravity


Maximum permissible backward shift of the center of gravity at the take-off, attained only with a ballast of 600 kg (1322.4 lbs) (in reconstructing the wing area, ballast is to be reduced considerably)

While landing the center of gravity is shifted forward 7% farther than at take-off


Position of center of gravity within the safety region.

Displacement of center of gravity slight (~ 1%)

C. REVIEW OF FLIGHT PERFORMANCES AND FLIGHT CHARACTERISTICS

1. The fact that the two compared airplanes are equipped with different propulsion units must be emphasized before a discussion of flight perfornances can take place. The differences in power caused thereby are practically of importance only at ground level or at low altitudes, and are especially of disadvantage to the Go P-60 since they reduce its power by 2.0 m/s (6.56 ft/sec) on the ground and on the runway by 120 m (393.69 ft). By transferring the propulsion units to the outside and by adopting an arrangement where the pilot is in a lying position, it becomes possible to keep the wing area in a Go P-60, in contrast to 8-229, about 12% smaller and to reduce the maximum thickness of the wing section to 13% as against 17.8%. Beyond that, symmetrical wing sections with a small leading-edge radius and a shift of the bulk of the ship towards the stern (50%) are being used in the Go P-60; also the sweepback is considerable. Because of these measures (small thickness of wing sections, small leading-edge radius, considerable shifting of thickness to the rear, strong sweepback and also small aspect ratios), it is expected that the start of the sharp rise in drag due to the approach of the flight speed to sonic velocity will be shifted in the Go P-60, as against 8-229, to larger Mach numbers (D M ~ 0.1).

The larger induced drag of Go P-60, effected by the lower aspect ratio, causes slight losses in climbing speed and ceiling which, however, is compensated by the smaller loaded weight.

The, additional drag, produced in a Go P-60 by removing the propulsion units from the wing, is partly balanced by the smaller wing area and by using thinner symmetrical wing sections. Beyond that, the magnitude of this additional drag depends largely on the possibility of transferring the propulsion units into the wing. The wing sections selected for Go P-60 are decidedly laminar sections. Should these wing sections still show laminar effects at the large Reynolds numbers with which we deal here, then the attainable cwF-value (without M-influence) in the region of high speed will be smaller than in 8-229. However, since the 8-229 as well as the Go P-60 perform at speeds where sound velocity is approached and where, consequently, a sharp rise in drag must be considered, this drag will decisively influence the maximum flight performances. Consequently, the Go P-60 is expected to show definite advantages over the 8-229.

Flight performances of both airplanes, as plotted in the attached graph, were ascertained under the same basic assumptions [DVL (Deutsche Versuchsanstalt für Luftfahrt) - measurements of wing sections, equal cw - additions for landing gear flaps, control surface slot, good construction of surfaces]; the increase of drag at high Mach numbers was considered according to the high speed measurements of DVL. Shift of the critical M-number by sweepback in the 8-229 was D M = 0.03, in Go P-60, D M = 0.05.

2) Flight characteristics

Since, in high speed airplanes investigated thus far, the dangerous disturbances of stability around the lateral axis start only at M-numbers higher than those at which the sharp rise in drag sets in, it is to be expected that, at least in horizontal flight and climb, the disturbances in the flight characteristics around the lateral axis will also follow the same tendency in tailless aircraft, especially since the outer control surfaces might become "critical" much later because of their thinner air foil sections.

In the Go P-60 as compared with the 8-229, the symmetry, practically one hundred per cent, of suction side and pressure side might show up favorably, since any asymmetry of wing sections or of the over-all structure of an airplane produced stability disturbances around the lateral axis in comparatively early stages of high speed performance.

Since, in tailless aircraft, the directional stability and especially the stability in turning and banking is rather weak, attention will have to be focussed on this problem in discussing these models. In the Go P-60, improvements are expected by placing the propulsion units backward and outward. Special measures have been planned in both airplanes for target approach. In order to increase the stabilizing effect while making a turn the 8-229 extends the air wing brakes, the Go P-60 the wing tip plates which also are used for directional control. However, installation of an automatic target flight control is recommended for both airplanes. Yet, adequate directional stability might be attained by merely installing vertical tail surfaces.

The vertical control surfaces and, consequently, the tactical brake flaps of the 8-229 are liable to present difficulties at high speed as a result of upsetting the entire distribution of pressure along a considerable part of the wing span. In this respect, it may be more favorable to adopt brake surfaces extendable at the wing tip, although the wide gap, forming at the wing tip, is a disadvantage.
An accurate coordination of the controlling components is exceedingly difficult due to the large dimensions of the control surfaces and the high speed of flight, for the required aerodynamic balance of control surface moments must be carried so far that the unavoidable allowances, to be made in production, will make the control, without special measures, practically impossible. In the 8-229 special difficulties might be expected in that respect, chiefly at high velocities, because extreme Frise-type control surfaces were adopted.
In the Go P-60 these difficulties are alleviated by subdividing control surfaces whereby only the smaller outer control surface is directly controlled by the stick, while the main control surface is indirectly controlled by the stick, and moved by a servo-rudder.

Because of the heavy sweepback, stability is assuredly more difficult to achieve in a Go P-60 than in a 8-229. But here, too, satisfactory performance characteristics are to be expected by applying the usual remedies against tipping hazards, such as: the familiar methods of fairing along the span, leading edge split flap, or slot.
The landing of tailless aircraft naturally calls for placing the center of gravity as far to the rear as possible. In the Go P-60 this is done by arranging the landing gear, fuel tanks and ammuntion to that effect; the center of gravity is slightly shifted to the rear when the landing gear is lowered, the fuel tanks become empty and the ammunition is expended. In the 8-229 conditions are less favorable, since fuel, ammunition, and landing gear are disadvantageously arranged in regard to the position of the center of gravity at landing. Compared to the take-off, the situation on landing shows the position of the center of gravity to be further in front (approximately 7% of the reference chord = 200 mm or 7.784 in). The Ca max values still attainable under these circumstances ought to become very small and, consequently, the landing speed will increase considerably.

Gegenüberstellung B-229/Go P-60
Gothaer Waggonfabrik, A. G.
Flugzeugbau-Entwicklung
January 27, 1945
7 pp., 2 illus.

Translated by Julius Selimerler
Edited by Dr. Robert Patek
Translation Section, Air Documents Div.
Intelligence (T-2), Wright Field, Dayton, Ohio
This is an AAF translation
21 February 1946

MBR/elk



INTELLIGENCE (T-2) HEADQUARTERS
AIR DOCUMENTS DIVISION AIR TECHNICAL SERVICE COMMAND
TRANSLATION SECTION WRIGHT FIELD, 21 FEBRUARY 1946


COMPARISON OF THE PERFORMANCE, WEIGHT, AND SIZE OF THE GO 8-229 AND GO P-60 All-WING AIRPLANES
COMPARISON OF WEIGHT IN 8-229-GO-P-60

Contruction Group


8-229


Go P-60


D G


Proof

Outer wing with aileron


1400 kg (3086.47 lbs.) (34m2)(365.97 sq. ft.)


900 kg (1984.16 lbs.) (27.6m2) (297.08 sq.ft.)


500 kg (1102.31 lbs.)


a) 19% smaller surface - 265 kg (584.22 lbs.).
b) other construction type not correctly dimensioned.
c) smaller load because of lighter weight.
d) small aspect ratio.

Center wing


1110 kg (2447.13 lbs.) (19m2)


915 kg (2017.23 lbs.) (18.8m2)


195 kg (429.90 lbs.)


considerably improved static construction. Eccentricities avoided.

Power plant


1735 kg (3825.02 lbs.)


1570 kg (3461.26 lbs.)


165 kg (363.76 lbs.)


difference between Jumo and BMW.

Ballast


600 kg (1322.77 lbs.)


_______________


600 kg (1322.77 lbs.)


Total armor plating


400 kg (881.85 lbs.)


290 kg (639.34 lbs.)


110 kg (2142.51 lbs.)


ballast armor plate.

Landing gear


345 kg (760.59 lbs.)


525 kg (1157.43 lbs.)


-180 kg (-396.83 lbs.)


take-over of Ju-88 landing gear; oversized.

Ammunition


210 kg (462.97 lbs.)


390 kg (859.80 lbs.)


-180 kg (-396.83 lbs.)


Pressure cabin


________________


120 kg (264.55 lbs.)


-120 kg (-264.55 lbs.)


1090 kg (2403.04 lbs.)

Gegenüberstellung Go-8-229
Go-P-60.
Microfilm Reel 2060 Frame 453
ADRC 14/8A5
3 pp., 2 illus.

Translated by Julius Schmerler
Edited by Dr. Robert Patek
Translation Section, Air Documents Div.
Intelligence (T-2), Wright Field, Dayton, Ohio
This is an AAF translatation
21 February 1946

MBR/elk

8-229 vs. Go-P.60

 

FLYING WINGS

Reimar and Walter Horten

Horten Ho IX

"The Horten Brothers flying wing bomber. It was intended to be a '1000' bomber, ie, it was supposed to fly at 1,000kph for up to 1,000kms, carrying up to 1,000kgs of bombs. The wing skins were made of a wood-carbon powder composite that absorbed radar pulses, so it would have been largely invisible on radar. Quite a project, but the war ended before it was fully developed."

Almost unknown today, the allwing twin-jet Go 229 was probably the most startling and unconventional warplane built during the WW2. It stemmed from the belief of the brothers Walter and Reimar Horten that a flying wing was the most efficient form of heavier than-air flying machine. They set out to prove this with a series of gliders, beginning with the Horten I of 1931.

From 1936 the brothers were officers in the Luftwaffe but continued their work which led in 1942 to studies for a flying wing jet fighter. Accordingly, work was hastened on two prototypes which was all the small team could contemplate. The HO IX V1 was to fly as glider, subsequently being modified to install two BMW 003 A turbojets. Gliding trials at Oranienburg began in about May 1944 and from the start the handling characteristics were outstandingly good.

In addition to the V1 and V2, seven more prototypes were ordered plus 20 production fighters. The Go-229 V2 began it's flight test program at Oranienburg in January 1945. Take off required less than 450 m and handling was superb. The programme advanced no further.

Reimar and Walter Horten
by Daniel Ford [copyright 1997, 2000]

A precis (cached below) of a longer work "posted on a Usenet newsgroup by John Powell about 1994" and itself part of a larger site also by Daniel Ford

Reimar and Walter Horten Reimar and Walter Horten tested their first piloted nurflugel (only-wing) sailplane in 1933, while they were still in their teens.

After further experiments, including a motorized sailplane, they built a twin-engined pusher that looked remarkably like the N-1M Flying Wing Jack Northrop would fly in 1940.

Alas, this Ho 5 crashed on its first flight in 1937, breaking the aircraft, Reimar's jaw, and one of Walter's teeth. The problem was that bugbear of all-wing aircraft: the center of gravity was too far back.

The Hortens moved the engines forward and lengthened the propeller shafts, so that their all-wing looked even more like the N-1M. Their Ho 5-B flew successfully in 1938--two years before Northrop's--but was then allowed to languish under the demands of war production. (One of Reimar's projects after the war began was an all-wing transport glider for the invasion of Britain.) Not until August 1941 was Reimar asked to explore the potential of the nurflugel as a fighting aircraft, and even then his work was largely clandestine, in an authorized operation arranged by his brother in the Luftwaffe.

In 1942 Reimar built an unpowered prototype with a 61-foot span and the designation Ho 9. After some difficulty the airframe was mated with two Junkers Jumo turbojets of the sort developed for the Messerschmitt Me 262. The turbojet was apparently flown successfully in December 1944, and it eventually achieved a speed of nearly 500 mph (800 km/h). After about two hours of flying time, it was destroyed in a February 1945 crash that killed its test pilot.

Its potential was obvious, however, and the Gotha company promptly readied the turbojet for production as a fighter-bomber with the Air Ministry designation Ho 299. (Because Gotha built it, the turbojet is also called the Go 229.) Supposedly it would fly at 997 km/h (623 mph), which if true meant that it was significantly faster than the Me 262--let alone the Flying Wings that Northrop was building. Fortunately for the Allies, the Gotha factory and the Ho 299 prototype--the world's first all-wing turbojet--were captured by U.S. forces in April 1945.

Like today's B-2 Stealth bomber (and unlike Jack Northrop's designs), the Go-229 had a comparatively slender airfoil, with the crew and engines housed in dorsal humps, and its jet exhaust was vented onto the top surface of the wing. The first feature made it faster than the stubby Northrop designs; the second made it even harder to detect, as did the fact that wood was extensively used in its construction.

One reason that the Ho 229 never got into production was that Reimar Horten was distracted that winter by another urgent project: the Ho 18 Amerika bomber. This huge, six-engined nurflugel was supposed to carry an atomic bomb to New York or Washington, despite the fact that the bomb was mostly theoretical, the engines probably couldn't have lasted the journey, and the plane couldn't possibly have been completed before Germany surrendered. (At 132 feet, its span was a bit less than that of the Boeing B-29 Superfortress, the largest warplane of World War II, but considerably shorter than the Northrop XB-35 that was in the works from 1941 to 1946.)

Several nurflugels came to the U.S. as war booty, including the center section of the Ho 229. Four of them are now back in Germany for restoration, with one to remain there when the work is finished, while the other three rejoin the collection of the National Air & Space Museum. A restored Horten sailplane is on display at Planes of Fame in Chino, California, which also owns a Northrop N-9M, a technology demonstrator roughly the size of the Ho 299, but much less sophisticated.

The future of the Ho 229 itself is uncertain. The center section is presently at the NASM Garber facility, and will eventually go on display at Dulles, but nobody knows whether it will be finished, or to what standard, or whether it will remain a partial relic.

A recent update on the restorations in Germany, as posted by Russ Lee of NASM on the Nurflugel list-serve:

"I visited the Deutschestechnik Museum Berlin last week to check progress on NASM's Horten Ho II, Hoo IIIf, Ho IIIh, and the Ho VI, V2. The H II has been finished for some time but left uncovered prior to exhibition in the new wing of the DTM scheduled to finish in 99 or 00. Enough wing parts and hardware remained to restore/reconstruct the right wing from the Ho IIIf. This work should be finished in a few months.

Drawings made of the rt wing componentsq will be used to build a new left wing. Work on the centersection will also begin later this year. DTM will begin cleaning and preserving the IIIh centersection next summer. We discussed building a plexiglas pod equipped desicant wheel, hygrometer and thermometer compartments to insure proper environmental conditions for long term preservation, and forklift cutouts to facilitate transport. The Ho VI, V2 wings have been separated from the H IIIf wing fragments and they are in quite good condition.

Unfortunately, several feet of leading edge is broken on both wings. We discussed the possibility of repairing the wing D-sections by blowing epoxy thinned with alcohol through a tube into each noserib bay. The Deutsches Museum at Schleissheim near Munich used this approach. I was able to inspect this project also and it appears they have done an excellent job repairing their set of original wings and reconstructing a brand new centersection from scratch."

Flying Wings : An Anthology : Reimar and Walter Horten

 

I normally do not post links to other forums. However, numerous original and more recent photos can be found at:

Horton Brothers Flying Wings

Horton Brothers Flying Wings - Aircraft of World War II - Warbird Forums

 

do you know what the plane was named

 

If anyone is interested, the National Geographic Channel will be airing a documentary on the Ho 229 entitled "Hitler's Stealth Fighter" on Sunday, July 5 at 11:00 am.

Hitler's Stealth Fighter - The National Geographic Channel


It evidently aired last Sunday, but I missed it.

-whatever

-Lou