Don't know about drag, but I read that the prone position was supposed to help the pilot cope with g-forces.
Horton Flying Wing
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GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
The prone position was popular for low-drag designs and was thought to help with high-G conditions as aircraft got faster.
One design that incorporated the prone position for both reasons, was the Hs132 jet dive-bomber.
One design that incorporated the prone position for both reasons, was the Hs132 jet dive-bomber.
Admiral Beez
Captain
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They used silver laden paint to simulate the internal metal structure. Here is the problem: the National Geographic and Northrop team roughly built a Horton Ho X based on the captured Ho X which was a testbed for the Ho 229. The Ho 229 differed in two important ways. Wing thickness and material.
1 When Horton initially received plans for the Jumo 004 it lacked an accessories gearbox. When they received their first Jumo 004B jet the accessories gearbox was now there (they hadnt been updated) and they were forced to thicken the wing to fit the engine. This lowered Mach limit. The actual Horton Ho 229 would get an slightly enlarged planorm and longer central chord to increase fineness.
2 The filler material between the plywood was changed to cheaper "formholz" plastic wood which is a sawdust, glue, graphite filler. The graphite was semiconducting and would have absorbed some microwaves. It was also about 2.5 cm thick which is about 1/4 wavelength for 9cm microwaves so waves reflected of the back of the material would antiphase cancel incident waves reflected of the front.
All this was well known so it's frustrating they missed it.
FLYBOYJ
"THE GREAT GAZOO"
I believe that it was mentioned on the National Geographic documentary that the inclusion of the graphite was not an attempt to make the aircraft radar absorbing. Personally I don't believe the silver laden paint would have made up for the actual amount of metal structure. Radar creep wasn't addressed either.
Crimea_River
Marshal
I take mine black.
Admiral Beez
Captain
I used to work with a women from Jamaica. She remarked on how I took my Tims, and I said "once you go black, you can't go back". She laughed and said, "that's not what that means..." It was a horrible work environment, but the humour and friendships got us through.
I learned about the 'formholz' from an article by Dr. David Baker in a magazine called Air International probably 20 years ago He never claimed it was a deliberate attempt at stealth, just mentioned that it should be a reasonable radar absorber combined with the Ho 229 shape. David Baker was English but had worked for NASA for 20 years before retiring and becoming an author. Wrote a book on the Me 262. You'd need to get a 16:1 reduction to halve radar detection range but it does make jamming easier. Nevertheless there was a lot of stealth research in WW2. In the US ferrite based paints were developed, these tended to work on only a specific frequency depending on ferrite grain size and were usually used to reduce interfering reflections around antenna,
German research program was quite large but run mainly by the German navy. Another program sought to create false radar landscapes and lakes using corner reflectors to seduce and confuse H2S/H2X. There was some stealth research at FFO (Luftwaffe's signals establishment) The Two radar absorbing materials the Germans had was "Schornsteinfehger" which was a Jaumann absorber used on u-boat masts (about 96% absorbent) and Wesch which was a PVC loaded with ferrite based absorber that could be moulded to any shape and absorbed 70% across a fairly broad range of frequencies. Both were used on u-boats masts. They also managed to combine the two but never deployed.
A believe a Jaumann absorber could have been incorporated into the skins of both the Ho 229 and Mosquito if someone had tried.
There is a BIOS/CIOS report on this and a German author called Fritz Trenkle wrote an excellent book on German radar warfare where he covers radar absorbing materials.
Admiral Beez
Captain
IK, we're playing with the subject line inaccuracy.
This wasn't aimed at you specifically, Admiral, just a general point. I thought the Tom Horton reference clever though, particularly the Go 229 with his logo!
Yup, German scientists conducted numerous experiments in radar absorption and radio wave distortion, including introducing the concept of what the British later called 'Window' before the British did, and even used it before the British as well. Despite these scientists and their work, there's no evidence that the Germans actually applied any form of radar absorbent technology to in-service aircraft at the time, they certainly didn't to the Horten flying wings. Again, the entire subject of these aircraft being 'stealthy' is retrospectively applied, and by consequence has led a hoard of people to put two and two together to make five and erroneously believe that they were indeed built as stealth aircraft, all because they watched a TV programme that implies it.
There is two more factors.
1 Reimer Horton claimed his aircraft, because they were built of wood, had some degree of 'radar camouflage'. So the designer claimed this in the 1950s and the claim originates with him. Reimer seems to have no signicantly understanding of the physics of radar absorbent materials at all but he had some justification on the basis of observation.
2 Wurzburg D radars had a computer attached that converted spherical coordinates to cartesian and spat out longitude, latitude, altitude coordinates and speed of the aircraft. They were often used during test flights to assist the test pilot. It was noted by radar operators that the Me 163 had a very low radar return. That was because a/ there was no propellers b/ there was no horizontal tail to help scatter radar and c/ the wings were wood (I believe). The same was noted with the Hortons earlier piston engine flying wings which featured plastic and wood construction and wood/plastic propellers. So you would have a radar operators saying that this blip looks a lot smaller than a conventional aircraft.
I've attached a PDF on the German navy stealth program.
Here is the link where I got it from:
CIOS XXVI-24 (cdvandt.org)
The Germans used several code-names for making their U-boats and other vehicles less visible to radar signals, like: Sumpf (ferrite based absorber) and Schornsteinfeger (jaumann absorber) and for aircraft: Schwarzes Flugzeug (Black aircraft)
It is understandable, that the Allied Intelligence would like to know about the German scientific approach in this field.
That the content of this report must have been of (some)significance is evident, as this report was finally declassified on 26 April 1960, thus, say, fifteen years after Germany had surrendered in May 1945.
It's fairly abvious that the Schornsteinfeger (jaumann absorber) could have been adapted to aircraft fairly easily if the NVK (german navy signals branch) had of been talking to each other.
The German versions of windows was called duppel. 5 x 25cm lengths cut to Wurzburg frequencies equalled radar cross section of one Me 109.
Note, the Mosquito had metal propellors, the Spitfire Wood. If Spitfire props had of been used on the Mosquito it probably would have had a reduced radar signature.
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Not every variant of the Spit had the wooden Rotol props. Spits also were fitted with de Havilland props, and no, it wouldn't. A spinning propeller presents itself as a solid disk to radio waves. Just because the Mosquito was made of wood, doesn't automatically mean it is somehow 'stealthy'.
Also, whether Reimar Horten presented that talk in the 50s or not, he did not show any interest in the radar absorbent properties of the aircraft he built in the 40s. There is no evidence of this at all. Again, Koopernic, you are putting two and two together to get five. There was no inclination to make these aircraft stealthy. It's a myth.
GrauGeist
Generalfeldmarschall zur Luftschiff Abteilung
No matter how "stealthy" the Ho.IX may have seemed, the return on the engine intakes would have been enough to light it up...
The return on the intakes of a Jumo 004 half burried in a fueselage would still be much less than the return on a metal cowled engine with a metal propeller, oil cooler maybe radiator and exhauist stubs.
What level of evidence do you want to accept that Hoten was considering the radar stealth? It seems the bar keeps getting raised.
A spinning propellor doesn't present itself a solid prop, it produces audio modulations at a frequency of engine RPM/60 x blade number.
When the RAF began dropping "Windows" to jam German Wurzburg radar the Germans added two anti windows devices one was Nuremberg which gave the elevation/azimuth opperator a headphone to hear these sounds so he could find a bomber quickly by listening. They gave the the scopes a supplementary trace to plot the phase of the target. A changing phase meant a moving target. Wurzburg was jammed by Carpet Jammers not windows.
Flying Wing Fighter "Horten IX"
by Doctor Reimar Horten
(as translated by: Fernando Walter Siarez, Buenos Aires, Argentina)
(The original article was titled "Ala volante Caza 'Horten IX' ", by Dr. Reimar Horten, published by Revista Nacional de Aeronautica, (today: Aeroespacio, Revista Nacional Aeronautica y Espacial) " May 1950, number 5, pages 19-20; Buenos Aires, Argentina. We thank them for allowing the translation and publication here for all to share. The article is being provided in both English and Spanish.)
The performances and qualities a modern fighter must have are very varied. In peacetime, the fighter development is always oriented towards its maximum speed, despite that there are many performances and qualities that determine its value during combat missions.
If the fighter is 100 Kilometers/hour [about 60-mph -Trans] faster than the bomber plane, it can overtake this latter and absolute speed is a secondary subject. During combat between fighters, higher speed is an advantage, as is higher climb rate and higher ceiling. Turning radius or time for a complete turn, are other performances that are not less important, to mention some of them.
To avoid combat, maximum speed is the only decisive one, but this is not the mission of a fighter. To intercept and achieve air supremacy, it is advantageous the higher starting position. If surprise factor fails, combat transforms into a "turning" combat. To be able to fly with small diameter turns, low wing loading is needed, from which a big wing results, what is advantageous for the practical ceiling. With this wing, take off and landing speeds, mainly the latter, are kept in an easy to dominate envelope and the amount of fuel carried aboard -that in jet aircraft can never be sufficiently large- allows satisfactory range values. The big wing does not decrease largely the maximum speed in jet fighters, because that is influenced only by aerodynamic design. This phenomenon comes from the fact that at such velocities, sonic speed is frequently achieved, so getting big additional drags. So, for example, the swept wing provides a mean to delay this drag increase, to much higher speeds.
Other factors of equal importance as speed, ceiling and turning radius also determine the combat value of a fighter. To describe them all will take us too far and is out of the scope of this article. I want only to remark the visibility of the aircraft. In the past, the detector was human eye, later it was the grounded radio that provided guidance until the airplane met the enemy. Today the pilot has the assurance of recognizing, even at night, an airplane flying many kilometers far, by means of the radar. In the past, planes were covered with camouflage paintings, and with the advent of radar, the already considered antique wood constructions, turned into something modern again. As reflection of electric waves on metallic surfaces is good, such is the image on the radar screen; on the contrary, on wood surfaces, that reflection is little, these resulting barely visible on the radar.
A fighter must use the surprise factor, especially at night; to do that, the plane must be built in wood, not only for the above mentioned circumstance, but also because the wood surface resistance to impacts is not necessary inferior to that of metallic surfaces, as was shown by tests. Also, those resistances are regarded of secondary importance, because with modern big gage guns, an impact means practically a total loss.
As far as landing speed is concerned, I want to say some words, because very often it is given a secondary importance: personally, I consider it very important because "cold losses" depend on it. Any loss is a victory for enemy. So, landing speed has great importance, besides the fact that it determines service possibilities in bad weather and at night. On the other hand, a pilot that has just ended a combat cannot be asked for high skill performances, needed with high landing speeds. Another point deserving mention, is that practice demonstrated that during a war, type specialization cannot be kept: the fighter drops bombs, takes part in ground combats, makes night interception and reconnaissance flights. Technology would like to solve a specific problem; anyway, it has to design the fighter as a multi-role aircraft and accept many compromises in such a way, that it must be able to carry bombs, or supplementary droppable tanks when it flies in a defensive mission; it must also be able to launch rockets, or be provided with an automatic movie camera, etc.
Guided by these thoughts, I built in 1943 the Horten IX model, from which two prototypes were built in the own firm, passing in 1944 to series construction under the license Gotha-Waggon Gotha. It is a flying wing of 16 meters span, equipped with two Junkers 004 turbine engines, built in three parts, the central wing section and two exterior parts. The central part that bears the load is 3.2 meters [10.5 ft -Trans] long and is built in steel tubing; in it the landing gear, turbines, weapons and pilot seat are fixed.
The turbines are inside the wing and receive air from the leading edge, without deflections. The cabin is put in the vertex of the sweep angle, between both motors, and is equipped with ejector seat, so as to allow the pilot to descend in parachute, without risk, at high flying speeds; besides the necessary armor, it has radio and identification instruments. Four MK 103 cannons, 30 mm gage, of 900 m/s of initial speed that produce a noticeable effect on the target and a ballistic corresponding to flight speeds. It has a hanging device for two bombs of 1000 Kilograms each, or for two droppable supplementary tanks, also of 1000 kilograms each. Its range is of 4000 Kilometers with 2400 kilograms of fuel in the wing, but it could be extended considering the very improved fuel consumption of today.
The landing gear, with nose wheel, had been designed for the aggravated conditions of night flying and was retractable to the wing center section. In spite of the low landing speed, of 140 kilometers per hour [87 mph -Trans], a detachable drag parachute had been installed, which allowed very short landing runs. In the center section also is installed a aerodynamic brake that permits a rapid adjust of the own speed to the enemy's own one, and that can be also used for landing. The cover shells are wood "monocoque" parts, easy to dismount for maintenance of the engines [and of ] the weapons. The second model was a two place one for night flights and training. The outer wing parts, completely built in wood, are of single spar construction. The leading edge is built in shaped wood, this is, milled wood, mixed with adhesive and then pressed to the definitive shape. By means of this construction method, a high quality product of any shape and size, can be made. The spar that transmits the forces from the wing fitting to the "monocoque", houses in its interior the command push rods. All wing space must be filled with fuel, using very simple rubber bags, attached to the monocoque. The rudders, mounted as brakes at the wing tips, produce a safe effect at any speed, and -by means of some manipulations- can also serve as elevators, so as to assure, even in supersonic flight (it can happen in a down pitch) total dominion of the plane.
After five years have passed since the last construction in Germany, I can demonstrate that the Horten IX has not been surpassed by more recent constructions. Speed records are, today as yesterday, over 960 Kilometres an hour [596 mph -Trans], its maximum speed, but the general design combination has not been excelled. The fact is that the construction principles should have been guided only by the physical phenomena arising from experiments with other built airplanes, without copying them. The contrast to this is the conventionally built airplane, resulting from the average of several ones, to be built
-Ala volante Caza "Horten IX" Por el Doctor Reimar Horten
Las performances y cualidades que debe tener un caza moderno son muy variadas. En tiempos de paz, se orienta siempre el desarrollo del caza hacia su velocidad maxima, a pesar de que son muchas las performances y cualidades que determinan su valor para el combate.
Si el caza tiene 100 kilometro por hora mas de velocidad que el bombardero, puede darle alcance a este, y la velocidad absoluta pasa a segundo plano. En el combate entre cazas, la velocidad mayor es una ventaja, como lo son la velocidad ascensional y techo mas elevados. El radio de viraje o tiempo de vuelta completa, son otras performances no menos importantes, para nombrar algunas. Para evitar un combate, la velocidad maxima es la unica decisiva pero esta no es la mision del caza. Para cazar y lograr con ello la supremacia en el aire, es ventajosa la posicion mas alta de partida. Si falla el momento sorpresivo, el combate se transforma en un combate de curvas. A fin de poder volar con un viraje de poco diametro se precisa una carga alar baja, de lo cual resulta la necesidad de un ala grande, que es ventajosa para el techo practico. Con esta ala, las velocidades de decolaje y aterri- zaje, principalmente la ultima, se mantienen en un marco facil de dominar y la cantidad de combustible llevadaque en los aviones con propulsores a chorro nunca puede ser lo suficientemente grandepermite lograr alcances satisfactorios. El ala grande no disminuye mayormente la velocidad maxima de los cazas con turborreactores, dado que aquella es influidad unicamente por el diseño aerodinamico. Este fenomeno se debe a que con tales velocidades se llega muy a menudo a la velocidad sonica, con lo que se originan grandes resistencias adicionales. Asi, por ejemplo, el ala en flecha proporciona el medio para diferir este aumento de resistencia, a velocidades muy superiores.
Otros factores de igual importancia que la velocidad, techo y radio de viraje, determinan tambien el valor de combate de un caza. Describirlos a todos ellos conduce demasiado lejos y no encuadra en la finalidad de este articulo. Quiero hacer resaltar unicamente la visibilidad del avion. Antes, el detector fue el ojo humano, mas tarde fue la radio que hacia de guia desde tierra hasta que el avion encontrase al enemigo. Hoy dia el piloto tiene la seguridad de reconocer aun de noche a un avion que se halle a muchos kilometros, por medio del radar. Antes, se cubria a los aviones con pinturas de camouflage, y con la aparicion del radar, las construcciones de madera ya consideradas anticuadas, volvieron a ser de actualidad. Debido a que la reflexion de las ondas electricas es buena en superficies metalicas, tambien lo es la imagen en la pantalla del radar; en cambio, en superficies de madera, la reflexion de dichas ondas es pequeña, por cuanto estas son apenas visibles en el radar.
Un caza debe aprovechar el factor sorpresa, especialmente de noche, para ello, el avion debe estar construido de madera, no solo por la circunstancia anotada, sino tambien porque la resistencia de superficies de madera a los impactos no es necesariamente inferior a la de las superficies metalicas, como lo demostraron los ensayos. Por otra parte, hoy dia dichas resistencias pasan a segundo plano, ya que con las modernas armas de gran calibre, un impacto significa practicamente un perdida total.
Con respecto a su velocidad de aterrizaje, quiero decir algunas palabras, pues muchas veces se le atribuye una importancia secundaria: personalmente considero muy importante en vista de que de ella dependen las "perdidas frias". Toda perdida es una victoria del enemigo. Por ello, la velocidad de aterrizaje tiene gran importancia, ademas de que determina las posibilidades de servicio en mal tiempo y de noche. Por otra parte no se puede pedir de un piloto que acaba de salir de un combate, que rinda grandes performances de destreza, necesarias con velocidades elevadas de aterrizaje.
Otro punto digno de mencion, es que la practica mostro que en la guerra no se puede mantener la especializacion de los tipos: el caza arroja bombas, interviene en combates terrestres, efectua vuelos de caza nocturna y de reconocimiento. La tecnica preferiria solucionar un problema especifico; sin embargo tiene que diseñar el caza como avion de servicio multiple y aceptar muchos compromisos de tal modo, que debe poder llevar bombas, o tanques suplementarios lanzables cuando vuela en mision de proteccion; tambien debe poder lanzar cohetes, o estar provisto de una camara de cinematografia automatica, etc.
Guiandome por estar reflexiones, construi en 1943 el modelo Horten IX, del que se fabricaron dos prototipos en la firma propia, pasando en 1944 a la fabricacion en serie bajo la licencia Gotha-Waggon Gotha. Es un ala volante de 16 metros de envergadura, equipada con dos turbinas Junkers 004, construida en tres partes, la central del ala y las dos exteriores. La parte central que soporta la carga mide 3.2 metros y esta construida de tuberia de acero; en ella tambien estan fijados el tren de aterrizaje, las turbinas, las armas y el asiento del piloto.
Las turbinas estan en el ala y reciben el aire del borde de ataque, sin deflexiones. La cabina se encuentra en la punta del angulo en flecha, entre ambos motores, y esta equipada con asiento lanzable, a fin de permitir al piloto el descenso en paracaidas, sin riesgo, a grandes velocidades de vuelo; aparte del blindaje necesario posee radio e instrumentos de identificacion. Cuatro cañones MK 103, calibre 30 mm, de 900 m/s de velocidad inicial, producen un efecto apreciable en el blanco y una balistica correspondiente a las velocidades de vuelo. tiene un dispositivo de suspension para dos bombas de 1000 kilogramos cada una, o para dos tanques suplementarios lanzables, tambien de 1000 kilogramos cada uno. Su alcance es de 4000 kilometros con 2400 kilogramos de combustible en el ala, pero se lo podria aumentar considerablemente, con los consumos de combustible actuales sensiblemente mejorados. El tren de aterrizaje, con rueda de nariz, habia sido diseñado para las condiciones agravadas del vuelo nocturno y era retractil a la parte central del ala. A pesar de la velocidad baja de aterrizaje, de 140 kilometros por hora, se habia instalado un paracaidas de freno lanzable con el cual se obtenian carreras de aterrizaje muy cortas. En la parte central se encuentra tambien un freno aerodinamico que permite amoldar rapidamente la velocidad propia a la del enemigo, y que tambien puede emplearse para el aterrizaje. Los recubrimientos son monocoques de madera, faciles de desmontar para el mantenimiento de los propulsores [ y de las ] armas.
El segundo modelo fue biplaza para vuelos nocturnos y de entrenamiento. Las partes exteriores del ala, completamente de madera, son de construccion monolarguera. El borde de ataque esta construido en madera perfilada, es decir madera molida, mezclada con un adhesivo aprensado a la forma definitiva. Mediante este tipo de construccion puede hacer un producto de alta calidad de cualquier forma y tamaño.
El larguero que trasmite las fuerzas de la toma del ala, al monocoque alberga en su interior las varillas de empuje de los comandos. Todo espacio del ala puede ser llenado con combustible, a cuyo fin se usan bolsas de goma sencillas, asguradas contra el monocoque. Los timones de direccion, montados como frenos en las puntas de ala, producen un efecto seguro con cualquier velocidad y -con determinadas manipulaciones- tambien efectos de timon de profundidad, a fin de asegurar aun durante un vuelo supersonico (como puede ocurrir en una picada) el dominio completo del avion.
Transcurridos ya cinco años desde la ultima construccion en Alemania, puedo demostrar que el Horten IX no ha sido superado por construcciones mas recientes. Los records de velocidad son, hoy como ayer, superiores a los 960 kilometros por hora, su velocidad maxima, pero no ha sido superada la combinacion del diseño general.
El motivo para el es que el principio de construccion debio guiarse unicamente por los fenomenos fisicos de las experiencias que se obtuvieron de otros aviones construidos, sin copiarlos. El contraste es el avion de construccion convencional, resultante del termino medio de varios, para ser construido
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Evidence, mate. Any evidence from official documentation produced surrounding these aircraft at the time they were conceived. The British captured what they could from Horten and interrogated him after the war and he was keen to co-operate on the details, even designing an aircraft he thought might have been of use to the British, but they weren't interested. Almost all this documentation survives in The National Archive at Kew, Richmond, UK. At NO time did he mention anything about radar absorbent qualities, so if you have loads of first hand documentation produced by Horten that somehow the British missed, would love to see it.
Until you can produce such evidence, all you are saying, no matter how much he spoke after the fact about radar absorbent material, is not conclusive and circumstantial only. There is NOTHING in ANY of the research these scientists did during the war that specifically pertains to Horten or his aircraft, which is what is up for debate here.
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Admiral Beez
Captain
Aren't birds, essentially flying bags of meat detectable on radar?
We had ground radar even in the Vietnam era, Early 70's, they used them at firebases on the perimeter .
They could detect people, tell if they were armed or not. And sensitive enough that operators could tell people from water buffaloes.
They could detect people, tell if they were armed or not. And sensitive enough that operators could tell people from water buffaloes.
