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 XIXth
century 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 18th
1944 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
On April 14th 1945, the American army arrived at the
production factory, capturing the Go 229 (Go for Gothaer the official
designation) ending the construction of what had been the first
jet propelled flying wing. One of those machines is located at
the famed Smithsonian museum.
The Horten brothers did not wait for the arrival of the Americans,
and as many of their compatriots, it is in Argentina that they
would continue to develop their flying wing. Although they had
been geniuses in the conception of airplanes, they had none the
less been members of the Nazi party.
They went on to design unorthodox gliders, the Horten XV "Urubu"
in particular and a giant transport glider the IAME I.A. 28, but
only one of this machine was ever built.
Disregarding their political involvement more or less doubtful,
the Horten brothers remain no less the "grand masters" of the
Their stubbornness in their researches resulted in the production
of a flying wing possessing great flying qualities, beginning
with the first one produced to the last one, even introducing
the piloting of the machine in a laying down position to reduce
the extra drag produced with a normal canopy configuration.
Reimar Horten died in 1994. As for his brother Walter, his life
ended in December 1998 in Baden-Baden.
And, what else can we say about the Horten brothers' Go 229 (or
Ho IX or Ho 229)?
It was a furtive jet propelled flying wing, operational some decades
before the F-117 "stealth" the airplane subject of so much publicity
during the Gulf War.