Before evoking the story of the Horten brothers and their strange machines, a review of some background is necessary.
As used as we are to visualize a traditional airplane with a fuselage, we are somewhat taken abashed when looking at a flying wing, and yet, its concept dates back from the dawn of aviation. The benefits of a flying wing become easy to understand when we consider that the fuselage and the tail section produce 30% to 50% of an airplane's drag, thus the reason that purists such as Lippisch or Northrop pursued this concept. The idea of a flying wing is far from being a novelty; it made its appearance at the birth of aviation, and it was a concept adopted by many precursors.
Another essential fact to keep in mind for the comprehension of the Horten brothers' work is to recall the importance that the glider and soaring played in the history of aviation.
While many researchers towards the end of the XIXthcentury were trying to create a motorized machine, some purists and grand precursors such as Lilienthal or Ferber believed that a flying machine should be aerodynamically efficient and easy to fly before installing an engine. We must note in passing that Lilienthal had conceived gliders without a tail section before the year 1900
The Horten brothers would become the virtuosos of the flying wing, testing with stubbornness their machines without neither fuselage nor tail section in gliding flight before even thinking of adapting them with an engine. Obsession? Maybe…Whatever the reasons, they would design flying wings exclusively. No other type of flying machine would come out of their drawing board.
Born at the beginning of the 20th century, the brothers had developed from childhood a passion for the concept of a machine flying with the purest of qualities. The Versailles treaty of 1919 theoretically banned the rearmament of Germany, particularly by drastically limiting its aeronautical production. This is how glider flying and soaring in Germany came to play such an important part between the wars, not only in the training of pilots but also in aeronautical research. The renowned Wasserkuppe meetings would provide the perfect stage for the advancement of those researches.
It is within this time frame that Walter and Reimar Horten developed, and built their first flying wing before reaching the age of twenty after studying the work of von Prandlt (published in 1918) on aerodynamics with the emphasis on the benefits of the thick wing. They also benefited from indulgent parents that allowed them to transform the family's house living room into a workshop.
During the entire period that preceded the Second World War, the brothers conceived machines having constantly improved performance.
Their first glider, the Horten Ho I, was first flight tested at Bonn-Hagelar in July 1933. Although it was not a complete success, it opened the way for other models, including the Ho IV with a high aspect ratio wing of 24 meters in span, as well as their Ho III that soared to 7000 meters in 1938.
When the hostilities began in World War two, the Horten brothers were of course assigned to the Luftwaffe. Wolfram, the third brother was shotdown over Dunkerque flying a Heinkel He-111, whereas Walter flew Messerschmitt Bf-109 for 6 months. Reimar was also trained on the Bf-109 but he was soon transferred to a special unit preparing for operation "Sealöwe" (Operation Sea Lion) having for objective the invasion of England. For this operation the Luftwaffe had created a special glider unit. More than 80 aircraft, had been assigned to this operation to deliver ammunitions and supplies for the troops of the invasion force, it included five Ho III and two Ho II especially equipped for this mission. The third Reich had once again found in the gliding schools a mean of "feeding" its war machine.
We know now that the tenacity and dedication of the British RAF pilots caused the invasion of England to be cancelled indefinitely. The cancellation of operation "Sea Lion" actually benefited the Horten brothers, permitting them to continue their projects, whereas the glider pilot training center was transferred to Königsberg. They concentrated on the repairs of their damaged gliders, and to the development of new models supported by Ernst Udet.
In 1942, the Luftwaffe advised Reimar that it was searching for an aircraft, which they could use to test a Schmitt-Argus pulse jet engine. They asked him if he thought that le Ho V two-seater could serve that purpose. According to certain sources, this decision came about following reports from German spies in the USA regarding the work of Northrop. The Ho V structure did not permit such mean of high thrust propulsion so the Horten brothers returned to the drawing board and conceived a stronger and larger wing. It would be the Ho VII, a machine equipped with two "pusher" type propellers and a pulse jet engine.
This new venture did not stop the brothers from pursuing their fundamental researches. As Etrich in 1908, they would be intrigued by the "flying seed" Zanonia Macrocarpia, which inspired them for the design of their amazing "Parabola".
But it was wartime and Göering was demanding his "1000X1000X1000". What was that all about? Nothing else than an airplane capable of transporting on a distance of 1000 kilometers from its base, 1000 kilos of bombs at a speed of 1000 kilometers per hour.
It was apparently a very unrealistic project for the era, but one that the Hortens (as well as other German engineers such as those from Focke Wulf) came very close to realizing and make operational.
Six months! That was the maximum time allowed to the brothers to have them conceive a prototype, including the assembly methods. It must be remembered that in 1944 the Luftwaffe was already in a desperate state. The glider prototype was ready in a very short time, built of materials consisting of plywood made with a special solvent resistant glue, and some parts of the machine were even made of composite material. Duraluminum had become a rare strategic material in Germany, and its use would have required highly qualified labor, which had been absorbed to serve on the battlefields.
On March 1st 1944, the Ho IX made its first gliding flight at Göttingen. A second machine had been built to be fitted with turbojet engines. Those turbojets promised for a March delivery were late to be delivered, and when they arrived it was a serious disappointment for the Horten brothers. They had been provided with Jumo 004B of 80 centimeters in diameter, whereas the planned jet engines were not supposed to exceed 60 centimeters! For a more classic machine such as the Me-262, it would not have been an insurmountable problem, but for a flying wing in which the jet engines were to be incorporated, it was a different problem. It would have been necessary to completely redesign the Ho IX, but time no longer permitted such a project. Or, it would have been necessary to substantially increase the wingspan, rendering the airplane unable to achieve the speeds adamantly required by Göering. The Horten brothers therefore resorted to "make do" ingenuity and the machine were ready for test flight at the end of 1944.
Test pilot Lieutenant Erwin Ziller's logbook shows that the first flight with the turbojet engines took place on February 2nd 1945, but Reimar Horten asserts that December 18th1944 was the date of this particular flight.
The RLM (German Air Ministry) had shown satisfaction with the Ho IX, and giving it the code 8-229 it entrusted its construction to the Gothaer Waggonfabrik works. Twenty of the machine's first model was ordered. Several other models had been planned, including two-seaters for training, and night fighters equipped with radar. We must note in passing that the Horten brothers had developed a special revetment for their Ho IX, made of glue, soot, and charcoal powder, making this already furtive machine practically undetectable with radar.
Walter Horten (born 13 November 1913; died 9 December 1998 in Baden-Baden, Germany) and Reimar Horten (born 12 March 1915; died 14 August 1993 in Villa General Belgrano, Argentina), sometimes credited as the Horten Brothers, were German aircraft pilots and enthusiasts, and members of the Hitler Youth and Nazi party. Although they had little, if any, formal training in aeronautics or related fields, the Hortens designed some of the most advanced aircraft of the 1940s, including the world's first jet-powered flying wing, the Horten Ho 229.
As used as we are to visualize a traditional airplane with a fuselage, we are somewhat taken abashed when looking at a flying wing, and yet, its concept dates back from the dawn of aviation. The benefits of a flying wing become easy to understand when we consider that the fuselage and the tail section produce 30% to 50% of an airplane's drag, thus the reason that purists such as Lippisch or Northrop pursued this concept. The idea of a flying wing is far from being a novelty; it made its appearance at the birth of aviation, and it was a concept adopted by many precursors.
Another essential fact to keep in mind for the comprehension of the Horten brothers' work is to recall the importance that the glider and soaring played in the history of aviation.
The Horten Brothers
The Horten brothers would become the virtuosos of the flying wing, testing with stubbornness their machines without neither fuselage nor tail section in gliding flight before even thinking of adapting them with an engine. Obsession? Maybe…Whatever the reasons, they would design flying wings exclusively. No other type of flying machine would come out of their drawing board.
Walter Horten in 1929
Horten Brothers with their first Glider
It is within this time frame that Walter and Reimar Horten developed, and built their first flying wing before reaching the age of twenty after studying the work of von Prandlt (published in 1918) on aerodynamics with the emphasis on the benefits of the thick wing. They also benefited from indulgent parents that allowed them to transform the family's house living room into a workshop.
First Step
During the entire period that preceded the Second World War, the brothers conceived machines having constantly improved performance.
Their first glider, the Horten Ho I, was first flight tested at Bonn-Hagelar in July 1933. Although it was not a complete success, it opened the way for other models, including the Ho IV with a high aspect ratio wing of 24 meters in span, as well as their Ho III that soared to 7000 meters in 1938.
The Horten V
When the hostilities began in World War two, the Horten brothers were of course assigned to the Luftwaffe. Wolfram, the third brother was shotdown over Dunkerque flying a Heinkel He-111, whereas Walter flew Messerschmitt Bf-109 for 6 months. Reimar was also trained on the Bf-109 but he was soon transferred to a special unit preparing for operation "Sealöwe" (Operation Sea Lion) having for objective the invasion of England. For this operation the Luftwaffe had created a special glider unit. More than 80 aircraft, had been assigned to this operation to deliver ammunitions and supplies for the troops of the invasion force, it included five Ho III and two Ho II especially equipped for this mission. The third Reich had once again found in the gliding schools a mean of "feeding" its war machine.
We know now that the tenacity and dedication of the British RAF pilots caused the invasion of England to be cancelled indefinitely. The cancellation of operation "Sea Lion" actually benefited the Horten brothers, permitting them to continue their projects, whereas the glider pilot training center was transferred to Königsberg. They concentrated on the repairs of their damaged gliders, and to the development of new models supported by Ernst Udet.
In 1942, the Luftwaffe advised Reimar that it was searching for an aircraft, which they could use to test a Schmitt-Argus pulse jet engine. They asked him if he thought that le Ho V two-seater could serve that purpose. According to certain sources, this decision came about following reports from German spies in the USA regarding the work of Northrop. The Ho V structure did not permit such mean of high thrust propulsion so the Horten brothers returned to the drawing board and conceived a stronger and larger wing. It would be the Ho VII, a machine equipped with two "pusher" type propellers and a pulse jet engine.
This new venture did not stop the brothers from pursuing their fundamental researches. As Etrich in 1908, they would be intrigued by the "flying seed" Zanonia Macrocarpia, which inspired them for the design of their amazing "Parabola".
But it was wartime and Göering was demanding his "1000X1000X1000". What was that all about? Nothing else than an airplane capable of transporting on a distance of 1000 kilometers from its base, 1000 kilos of bombs at a speed of 1000 kilometers per hour.
It was apparently a very unrealistic project for the era, but one that the Hortens (as well as other German engineers such as those from Focke Wulf) came very close to realizing and make operational.
Six months! That was the maximum time allowed to the brothers to have them conceive a prototype, including the assembly methods. It must be remembered that in 1944 the Luftwaffe was already in a desperate state. The glider prototype was ready in a very short time, built of materials consisting of plywood made with a special solvent resistant glue, and some parts of the machine were even made of composite material. Duraluminum had become a rare strategic material in Germany, and its use would have required highly qualified labor, which had been absorbed to serve on the battlefields.
The Horten IX
On March 1st 1944, the Ho IX made its first gliding flight at Göttingen. A second machine had been built to be fitted with turbojet engines. Those turbojets promised for a March delivery were late to be delivered, and when they arrived it was a serious disappointment for the Horten brothers. They had been provided with Jumo 004B of 80 centimeters in diameter, whereas the planned jet engines were not supposed to exceed 60 centimeters! For a more classic machine such as the Me-262, it would not have been an insurmountable problem, but for a flying wing in which the jet engines were to be incorporated, it was a different problem. It would have been necessary to completely redesign the Ho IX, but time no longer permitted such a project. Or, it would have been necessary to substantially increase the wingspan, rendering the airplane unable to achieve the speeds adamantly required by Göering. The Horten brothers therefore resorted to "make do" ingenuity and the machine were ready for test flight at the end of 1944.
The Horten 229
Test pilot Lieutenant Erwin Ziller's logbook shows that the first flight with the turbojet engines took place on February 2nd 1945, but Reimar Horten asserts that December 18th1944 was the date of this particular flight.
The RLM (German Air Ministry) had shown satisfaction with the Ho IX, and giving it the code 8-229 it entrusted its construction to the Gothaer Waggonfabrik works. Twenty of the machine's first model was ordered. Several other models had been planned, including two-seaters for training, and night fighters equipped with radar. We must note in passing that the Horten brothers had developed a special revetment for their Ho IX, made of glue, soot, and charcoal powder, making this already furtive machine practically undetectable with radar.
Walter Horten (born 13 November 1913; died 9 December 1998 in Baden-Baden, Germany) and Reimar Horten (born 12 March 1915; died 14 August 1993 in Villa General Belgrano, Argentina), sometimes credited as the Horten Brothers, were German aircraft pilots and enthusiasts, and members of the Hitler Youth and Nazi party. Although they had little, if any, formal training in aeronautics or related fields, the Hortens designed some of the most advanced aircraft of the 1940s, including the world's first jet-powered flying wing, the Horten Ho 229.
The first Horten in Museum
A design from the NAZI stores
Full scale replica built by Northrop Grumman to test radar signature
No comments:
Post a Comment