THE HORTEN TAILLESS AIRCRAFT
By K.G. Wilkinson, B.Sc. D.I.C. October 1945
1. This report cover the activities of the
Brothers Horten, at Bonn, Germany on the Horten Tailless Aircraft. This
flying wing type had reached an advanced stage of development with a high
degree of controllability and performance. The report is both historical
2. The collection of material on this tailless aircraft was brought about
by an investigation of a C.I.O.S. Team of the Horten home at Bonn in March
1945. In May 1945 the Horten Brothers were interrogated in England, and
final interrogation was carried out by a team sponsored by the Tailless
Advisory Committee in September 1945. Such information has been collated
and presented in this report.
3. The reports set forth the career of the Horten Brothers on tailless
aircraft development from their first glides in 1927 to 1945. During that
period the brothers developed many models of their craft, beginning with
the H I and ending with the H XIV. These models ranged from single seat
glider model to a six-engine trans-Atlantic transport. Models of the craft
were driven by engine-propeller units and by jet propulsion. Also at
various times models of the craft carried the pilot in seated and prone
4. The Hortens started their careers as aircraft designers in a very
practical way without assistance from “highbrow” theory. Early designs
were based mainly on what they found satisfactory on a small-scale model.
Wing sections were designed from scratch and were seldom tunnel tested.
5. From the first the Horten Brothers have been of the opinion that the
flying wing is the most efficient form of aircraft, and all their efforts
have been directed towards achieving this ideal.
6. Drawings and photographs of most of the models are included, together
with design data, stress analyses, equations, charts and tables. Weight
and performance figures are given, flying characteristics are described,
and stability, stall and recovery characteristics are discussed. Spinning
characteristics were tested with different centre of gravity locations.
7. Many novel features are shown, such as waggle tip control, spoilers,
elevons and drag rudders. In the various models wings have been given
sweepbacks from 9.5° in the conventional type wing to 60° in the arrowhead
type. Aspect ratios have ranged from 4 to 32.4.
In March this year a C.I.O.S. team visited the original home of Horten
Aircraft in Bonn, and brought back information on the recent activities of
the brothers Horten which revealed that their development of the flying
wing type had reached an advanced stage. Several powered types of great
interest had been built and flown, and a six-engined flying model of a
transport plane half completed.
Later on the Hortens were interrogated in England and a party form R.A.E.
followed this up by visiting the Horten factories and flight test center
in Germany in an attempt to find and preserve some of the more useful
aircraft. The trip was disappointing in that all the power aircraft except
the half completed H VIII were found to be destroyed. One glider was,
however, brought back.
Finally, in September, a party was sponsored by the Tailless Advisory
Committee to visit Germany for further discussion with the Hortens and
others interested in tailless problems. The following note is the result
of a collation of all the interrogation reports on the Hortens and is an
attempt to present a consistent and fairly complete account of their work.
Prof. Hill (Part Time)
S/Ldr. Kronfeld (A.F.R.E.)
Messrs. Prower (General Aircraft, Ltd.)
Watson (Armstrong Whitworth Ltd.)
Lec (Handley Page Ltd.)
The activities of the Horten Brothers in the design of tailless aircraft
have been reported at various times in the German journal “Flugsport” and
translations have been published by R.F.E. during the war. Their more
serious efforts based on early experience with gliders were not well known
until a C.I.O.S. team investigated the Horten home at Bonn (March 1945)
and interviewed Herr Berger who who supplied information of many of their
After the cessation of hostilities, the Horten Brothers were interrogated
in England (May 1945) and in the first two weeks of June 1945 the writer
visited Germany, with the Hortens, and investigated their center of
activity. Final interrogation was carried out by a team sponsored by the
Tailless Advisory Committee in September. The material from these
investigations has been collated and a fairly complete picture of the
Horten development is presented in the following report. The complete
series of aircraft is described in some detail and the design methods used
are summarized. Results from flight tests on performance and handling are
given where possible, but no written evidence in the way of reports or
calculations were found by an of the investigators. This feature is
unfortunate since many of the figures quoted for performance, etc., are
dependent on the accuracy of Reimar Horten’s memory.
Only one aircraft (the H IV sailplane) was discovered in the British
sector in Germany in a condition suitable for transport to England for
test flying. Other gliders were found in the American and French sectors
but all the power aircraft were so badly damaged as to be useless.
Illustrations for the report have been prepared from general arrangement
drawings of the early gliders (I, II and III) published in the German
technical press together with drawings of the later aircraft found in
Germany. Photographs were supplied by Reimar Horten or taken by the
Walter and Reimar Horten commenced their experiments on tailless aircraft
at the ages of 11 and 10, respectively, by building and flying small
models. In 1927 they started gliding and in the following years helped the
Bonn group at the Wasserbuppe. By 1932 Walter had his C glider license and
an A2 power license, and Reimar had his C glider license and had started
In 1933 they started work on their first man carrying glider which they
built in the family home in Bonn. Trials began with bungee catapult
launches on level ground; auto and winch launches were tried without much
success and finally it was aero towed. About two hours flying were done up
to March 1934 and later that year it won a prize at the Rhön gliding
competitions as an original design. Longitudinal stability seemed to have
been fairly good but lateral control was unsatisfactory (due mainly
apparently to adverse yawing moments from the ailerons), and longitudinal
control became very ineffective at low speeds.
After the 1934 Rhön contest the first aircraft was scrapped and work
started on the Horten II, which incorporated lessons learned on the
previous H I. This was finished in May 1935 but could not be entered for
the Rhon, so a 80 hp engine was fitted (Fig. 1) and extensive test flying
At this stage the brothers were called up for military service, but
continued to work on their tailless designs and during 1936 schemed the H
III and IV (gliders) and the twin engined H V. Two more H II’s were built
and entered by the Luftwaffe for the 1937 Rhön contests. No great success
was achieved because the brothers were out of practice. General Udet
was interested in the Horten’s work and asked Hanna Reitsch to test a H
II, in December 1938, and give an independent assessment. Her report
showed that considerable development was necessary in
control design but that the aircraft had some very good features, in
particular the behaviour at the stall was good and the longitudinal
damping satisfactory. Mail troubles were with lateral and directional
Whilst studying at the Bonn Technical High School in 1938 and 1939 the
brothers organized the construction of a number of H III’s which were paid
for by the Ministry of Education. Two of the type were entered for the
1938 Rhön contests flown by Bloch and Scheidhauer (later their chief test
pilot). Remarkable performances were put up by both aircraft. On August
6th Bloch climbed to 26,000’ in a cumulo-nimbus cloud. He had to abandon
his aircraft (probably due to icing troubles) and was unfortunately hit by
it and killed on the way down. He had a special fixed auxiliary front
aerofoil fitted to his H III to assist in performing tight circles.
Scheidhauer also iced up in the same cloud and had to take to his
parachute. During this period the H VII, a development of the H V (which
had been built to the Horten designs and was already flying) was projected
but could not be built. Discussion took place with Heinkel and
Messerschmitt with a view to engaging Reimar on tailless projects but
nothing came of the negotiations.
From 1939 to 1942 the brothers were again in the Luftwaffe and Walter, by
devious means managed to get an H IV (a new high aspect ratio sailplane)
build at Konigsberg where he was stationed. This clandestine construction
was discovered by his commander and Walter was sacked.
In 1942 Nortrhop’s work in America attracted attention in Germany and
Walter was ordered to restart development. Luftwaffe Sonder Kommando 9 was
set up with 200 men, factory premises and government grants to the tune of
L500,000 for getting machinery. Headquarters were at Gottingen and the
Peschke works at Minden was used to build Horten designs. (This was a
furniture factory which turned over to aircraft components during the war
years.) Many other dispersed workshops and test and design groups were
organized. Construction of the VII was authorized and it was flown
successfully in 1943.
Official enthusiasm waned again in 1943 when the quantity order for the
VII was cut, but they continued to work without authority and started the
H IX as a private venture. Official interest revived when it was half
completed and Goring ordered them to finish it quickly. It flew as a
glider in 1944 and design work was started on the H VIII which they
succeeded in selling to R.L.M. Their high performance glider H VI also
flew in 1944.
The powered H IX flew in January 1945 at Oranienberg. It was demonstrated
to Goring in March and the Gotha concern got an order to put the design
into production and build 20. On March 12th a conference was called at
Carinhall at which Goring presided and it was decided that the Chief of
the Air Equipment Branch should consider immediate inclusion of Horten
development and production work into the Fuhrers’ emergency programs. The
meeting put on record that it considered the flying wings produced by the
Hortens to point the way for future development of all aircraft
(presumably excluding rotary aircraft). The State Research Council was
ordered to organize a group of specialists to cooperate with the Hortens
in future development work, and give the brothers all possible support.
Production for training purposes was ordered to recommence.
There the story of the Horten’s tailless work finishes; a remarkable
record of progress made in spite of obstacle. In the early stages work was
only kept going by a genius for getting people to work for nothing and in
the end continuity had to be achieved in spite of fluctuating official
support. In addition to running a very complex and dispersed organization,
the brothers, with assistance on calculations from their sister, had to
grapple with aerodynamic and engineering problems on a bewildering variety
of aircraft. This side of the work was run mainly by Reimar who remained
independent and original in his thought throughout and got little help
Apart from the design and production of the VII, VIII and IX, which
represented an ambitious series, time and resources were found to pursue
the old interest of glider design. By 1945 serious production of the III
and IVb had been organized, amount to about four a month and two new
gliders were constructed – the aerobatic H XI and the mass production H
XIV sports sailplane, designed to the Olympic Games specification.
Concurrently with this work a new two-seater private owners aircraft with
a 100 hp engine was designed, and one built and flown as a glider. Serious
thought was also being given to supersonic aircraft and tentative steps in
this direction were taken with the research designs H XIII and H X.
In reviewing the Horten achievements one cannot help being impressed with
the speed of their work and the utter irrelevance of much of it to the
German war effort. Prototype gliders were knocked up with astonishing
speed with the very minimum of drawings. Although the basic design and
general arrangement were soundly worked out by Reimar, detail work was
largely settled by the workmen on the job with occasional interference
from Horten. Perchke was reduced to despair by the Hortens on many
occasions because they were always altering details as the design
progressed and he could never get the production drawings tidy.
There is no doubt that much of the work on sailplanes was a dead loss to
Germany – for example the HVI, H IX and H XIV and the motor sailplane IIId
had no connection with military or civil designs and taught no useful
lessons. Much of the work was without R.L.M.’s consent, and Reimar
commented that an advantage of dispersal was the R.L.M. could not find out
what was going on, or how their money was being spent. An extreme example
was the second glider H VI, which was started at Bonn, moved to Hersfled
when the Allies threatened Bonn and finished just before the Armistice. It
was then hidden in a barn where we found it in June 1945. The construction
took about 8000 man hours. Reimar said that he preferred building
sailplanes because he could do the complete design himself.