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.
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.
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