Flying Wings between the wars
by E.T. Wooldridge
As the world entered the roaring twenties, what has been called the
"Golden Age of Aviation" began, and interest in tailless aircraft revived
and spread. Many of the early proponents of the concept were gone; some
had abandoned the idea for more practical and profitable designs; some,
like J.W. Dunne, ceased their aeronautical activities, though their
theories and experiments provided guidance and inspiration for those who
followed (including Hill of England, Lippisch and the Hortens of Germany,
and John K. Northrop of the United States, the man who would eventually
carry the flying wing to its ultimate stage of development).
Rene Arnoux of France was one the early pioneers who
had not lost his interest in tailless aircraft during the war. He resumed
his experiments in the early 1920s, building a tailless biplane from
surplus parts. The strange looking hybrid, which incorporated Arnoux's
"flying plank" which flew successfully 12 times between February and April
1922, with some interest shown the press. Unfortunately the airplane
crashed, severely injuring the pilot, Fetu. It was rumoured that Fetu had
removed the stops restricting downward travel of the controllers, making
the airplane unstable.
During this same period, Arnoux formed his own company,
Simplex, and teamed up with a well-known French fighter pilot, Georges
Felix Madon. Fourth ranking French ace of World War I with 41 victories,
Madon became closely associated with Arnoux as his test pilot for several
years, to the extent that "Arnoux" designs became "Madon" designs in the
minds of many.
The first Simplex design, and perhaps the most
controversial of the Arnoux line, was the Simplex-Arnoux tailless racer,
constructed for the 1922 Coupe Deutsch race. The aircraft had a simple
Arnoux "flying plank" wing, with full span controllers, tiny vertical fin
and rudder, and was powered by a 3_20-hp Hispano Suiza engine. The machine
was said to have a maximum speed of' 236 mph, fast indeed for that day.
French ace George Mix Madon, who had 41 dogfight victories in World War I,
poses by the futuristic Simplex Arnoux racer of 1922. The pilot's vision
forward and down was severely restricted by the Lamblin radiator perched
on top of the fuselage and the expanse of the Arnoux "flying plank" Wing.
Press coverage of the revolutionary design increased as
the September 30 race date approached. Arnoux, not known as a publicity
seeker, was not even listed as designer. The airplane was now the Simplex
(type Madon Cannier), after the pilot Madon, whose name was now totally
identified with Arnoux designs, and an engineer named Carmier, who had
contributed significantly to the design. Regardless of who deserved credit
for the design, it seemed a bit too risky for its purpose, and whatever
chances it might have had in the upcoming Coupe Deutsch,
disappeared shortly before the race. Madon crashed on September 24 during
a landing attempt, demolishing the racer but sustaining only minor
The last of the Arnoux aircraft was this 1923 hybrid combination of a
Hanriot HD 14 and miscellaneous spare parts, all put together with
considerable imagination. It actually flew well according to official
This accident, coming as it did so soon after Fetu's
biplane crash, did little to increase popular acceptance of the Arnoux
design. There is little documentary evidence that Arnoux continued to
produce designs under his name, although in 1933 he apparently
collaborated with another advocate of tailless craft, Charles Fauvel.
Reports do exist of test flights in 1923 of a Madon tailless aircraft that
is obviously a derivative of the ill-fated 1922 Arnoux biplane.' The
airplane appeared to be nothing more than a Hanriot HD 14 sawed in half,
with a large single rudder added just aft of the cockpit. According to
test pilot Madon, this arrangement resulted in extremely sensitive
directional control. The upper ailerons were rigged to act as elevator
trim tabs controlled by a hand wheel in the cockpit. The lower wing
ailerons acted as elevators and ailerons.
The Madon airplane demonstrated satisfactory flying
characteristics, required no special training for the ordinary pilot, and
showed definite promise as a military aircraft. Interestingly enough,
Madon was given credit as the inventor of the aircraft.
Not long after his 1923 demonstration flights, Madon
gave up the tailless project, joined the Bapt round-the-world expedition
for a few short months, and finally rejoined the army in July 1923. He
died during an airshow at Bizerte, Tunisia, on November 11, 1924, when he
experienced an engine failure at low altitude, and crashed after
courageously manoeuvring his aircraft to avoid the crowd.
Another visionary whose interest in the tailless
aircraft began before the war was Alexander Soldenhoff. Born in Geneva in
1882, Soldenhoff immigrated to Germany in 1908 and began a professional
career as a painter, writer, and decorator. Although he was an artist by
trade, Soldenhoff had a consuming interest in aviation, particularly in
the development of powered tailless aircraft. He obtained his first
official patent for a tailless aircraft in 1912, and experimented
extensively for many years with models and wind tunnel tests to perfect a
practical, inherently stable, tailless monoplane. His first powered
aircraft flew in 1927. The aircraft, designated A1, was a single
seat, swept wing aircraft powered by a 32-hp Bristol Cherub engine with a
pusher propeller. After two test flights, test pilot Ernest Gerber
experienced a strut failure in flight and made an emergency landing at
Dubendorf airport in Switzerland.
Restricted from further flights by Swiss officials,
Soldenhoff shifted his activities to Germany, where his second effort, the
A2, was designed and constructed with the assistance of engineers Langguth
and Friedman. Completed in 1929, the A2 was test flown by the renowned
German sailplane pilot, Gottlob Espenlaub, who also built and flew his own
tailless designs. The two-seater A2 had conventional tricycle landing
gear, pusher propeller, and two trailing-edge control surfaces on each
wing. Successful flight test of this configuration encouraged Soldenhoff
to build the third of his experimental aircraft, the A3.
AlexanderSoldenhofr's second tailless airplane, the A2 (D-1708), was flown
in 1929 by noted German aviator, Gottlob Espenlaub. Two movable control
surfaces can be seen on the trailing edge of each wing.
A two-seater like its predecessor, the A3 had a
tricycle landing gear with the single wheel aft, under the pusher
propeller. This was the first Soldenhoff design powered by a French
Salmson 9-cylinder, 40-hp engine, with which all of his later designs
would also be equipped. Also appearing for the first time were two control
rudders, one mounted about mid-span on each wing.
Test pilot for the A3 was Anton Riedeger, who did all
of the test flying on the A3, A4, and a later model, the A5. Riedeger flew
the A3 for the first time on July 30, 1930, from Dusseldorf-Lohausen.
Riedeger, an experienced commercial pilot, was pleased with the flight
characteristics of the A3. Unfortunately, after a week of extensive test
flights, Riedeger was seriously injured and the airplane was destroyed
during an attempted crosswind landing.
Undaunted, Soldenhoff produced the A4, another design
quite similar to the A3. The streak of bad luck continued, however, when
the A4, with the intrepid Riedeger once again at the controls, crashed in
a gusty crosswind and flipped over. Riedeger was again injured, though
less seriously than before.
The Soldenhoff A4 prepares for takeoff at Boblingen Field, Germany, in
January 1931. Riedeger had no better luck with the A4 than he had had with
its predecessor. A crash left the A4 inverted in the snow and Riedeger
with minor injuries.
The last Soldenhoff machine to fly was his A5, a design
similar to its predecessors, but with a conventional tricycle gear and
distinctive discs, or endplates, at the wing tips. These plates could be
changed in the search for a more efficient aerodynamic design. The A5
apparently flew well. Soldenhoff and Riedeger set off together in the
two-seater on an aerial tour of Europe. The combination of the
accident-prone but determined Riedeger and the deaf artist/designer
Soldenhoff in the open cockpits of their flimsy experimental aircraft
hardly inspired confidence in the successful outcome of the trip. An
instrument takeoff in dense fog followed by occasional blind flying in the
clouds over the Swiss Alps using the rudimentary instruments of the day
added to the spirit of adventure as the two departed on the first leg of
their tour in September 1931. Although the tour barely got underway before
it was aborted for a variety of reasons, the fact that it started at all
was a tribute to the enthusiasm and determination of both the pilot and
Riedeger flies the A5. Many of the design features of Soldenhoff models
would be observed in later tailless aircraft in other countries.
A later design, the S5, was constructed along lines
similar to his previous models. It was never flown, and the project failed
for lack of official Swiss support.
Considering Soldenhoff's lack of technical training, it
is amazing that he made the progress that he did with his designs. The
artist suffered, not surprisingly, from lack of financial support and
governmental interest. He by no means solved all the problems of tailless
design, but his concepts provided the basis for many subsequent sport
plane configurations, including the roadable airplanes of the 1930s.
In 1923, an innovative Englishman, Professor G.T.R.
Hill, began his investigations into the questions of control and the
problems of designing a safe airplane. Hill studied sea birds and
concluded that they used wing warping and changes of wing camber rather
than their tails for longitudinal control in normal flight. Consulting
during this period with J M. Dunne, Hill eventually designed a family of
unusual tailless aircraft known as the Pterodactyls, after the prehistoric
Professor Hill's 1934 Pterodactyl Mk. V was designed as a
two-seater fighter for the Royal Air Force. The rear seat was for a
gunner. Control was afforded by balanced flaps on the upper wing that
operated together as elevators and differentially as ailerons. Wing tip
rudders provided directional control and also acted together as air
brakes. The machine was fully capable of aerobatics and inverted flight.
Hill's appreciation for the dangers associated with
stalling an airplane stemmed from his early days as a test pilot for the
Royal Aircraft Factory at Farnborough, England, in 1916. He had studied
the reports on Lilienthal's glider experiments, and knew of his death as a
result of a stall in his glider. He was also deeply concerned over the
tragic loss of about 50 lives a year in the Royal Air Force due to
Professor Hill sought solutions to the stall problem
over a number of years; his experiments eventually led to a non-stalling,
tailless glider in 1924. It was a monoplane and featured movable wing tip
"controllers" that provided longitudinal and lateral control regardless of
the airplane's attitude. When operated together, the controllers acted as
elevators; operated differentially, they acted as ailerons. Successful
gliding tests with the aircraft led to powered flight of the first
Pterodactyl a year later, which occurred on November 2, 1925. Subsequent
flight tests proved the soundness of Hill's theories, for there was no
definite stall, and good control was retained even at high angles of
England's distinguished G.T.R. Hill designed this Westland-Hill
Pterodactyl Mk. IA in 1928. This experimental tailless monoplane had
pivoted wing tips that served as both ailerons and elevators and that
remained effective regardless of the airplane's attitude.
During the next seven years, Westland Aircraft Works
produced five models of the Hill-designed Pterodactyl, the last, the Mk. V
of 1932, a two-seater fighter capable of 190 mph. Hill's Pterodactyls
incorporated many novel features, including the first use of variable wing
sweepback during flight, the use of spoiler air brakes and bicycle-type
tandem-wheel landing gear with wing tip skids, and the first use of wing
tip slats on a swept back wing. The Pterodactyl Mk. IV was the first
tailless aircraft ever to be spun, rolled, and looped.
Although the Mk. V was the last of the Pterodactyl
series, G.T.R. Hill continued to research tailless aircraft during a
brilliant career as engineer and academic. It is a tribute to his genius
as an innovator and designer that many of the Pterodactyl design features
appeared in later variations of tailless aircraft and flying wings.
Flying the Atlantic in a giant airliner was also the
dream of the Austrian engineer, Dr. Edmund Rumpler. Builder of the
well-known Taube series of World War I fighters designed by Igo Etrich,
Dr. Rumpler also saw the utility of a large wing to house passengers,
cargo, and engines. He did see a limit to increasing the span and size of
airplanes designed according to conventional practice, however. If
aircraft progressed in size beyond a certain limit, Rumpler theorized, the
weight of wings increased out of proportion to the increased size of the
airplane; the larger the airplane became, the smaller the payload capacity
Dr. Rumpler believed that the weight could be kept
within reasonable limits if it were distributed evenly over the wing span
instead of being concentrated in a single fuselage or hull. His plan was
to arrange a number of small airplanes side by side and join their wings.
The larger aircraft that evolved would have high load capacity and very
long range. The airplane was not a tailless design. Rumpler shared only
some of the theories advanced by the purists; he advocated eliminating the
fuselage, but retained the tail surfaces.
A forerunner of the "spanloaders" of the future was Dr. E. Rumpler's
Double Flying Boat design o the late 1920s. Four and six hull
designs were considered, but eliminated, since excessive stress on the
wing structure joining the hulls would probably have been generated during
operation in heavy seas.
Dr. Rumpler publicized his concept of a transoceanic
airliner in 1926 and, over the next four years, worked on the detailed
design while searching for financial backing in Europe and the United
States for full scale production.
The all-metal, twin-hulled flying boat was to have a
single wing with a span of 289 feet and a height of 8 feet at its thickest
point. Sixty-five tons of fuel would be carried in the twin hulls; fuel
would be fed by pumps to the ten 1000-hp engines, which would give the
gigantic craft a cruising speed of 185 mph.
The accommodations for the 35-man crew and 135
passengers were lavish. Cabins were to be situated in the wing interior at
the leading edge. Cabins would seat six, each with a breathtaking view
forward. A wide passageway extending the entire span of the wing would
separate the passenger cabins from the engine compartments at the trailing
edge. The passageway, over six feet high, would serve as a promenade deck
as well as sound buffer for the passengers.
Dr. Rumpler planned to build an entire fleet of these
boats to ply the oceans of the world. Like so many other similar schemes,
however, the Rumpler Double Flying Boat was only a paper airplane. He
failed to gain the necessary funds for the project at home or abroad and
was not in favour with the German government after Hitler's rise to power.
He did, however, sum up the fascination that he and so many others had
with the "big wing" concept: "Give me wings large enough and sufficient
motive power and I'll take the earth for an airplane ride."
Dreamers, visionaries, and conceptual designers
abounded in the field of flying wing design. Few could take the concepts
and apply them to a design with popular appeal. One who overcame the odds
was Charles Fauvel of France, the only designer seriously involved in
early development of tailless aircraft whose name remained associated with
the design and production of those designs half a century later. Fauvel's
first powered tailless craft flew in 1933; today tailless gliders with the
Fauvel name still fly in many countries around the world.
The Fauvel AV2 was one of the first of Charles Fauvel's tailless designs
produced in the early 1930s. Fauvel designs endured for 50 years, with
tailless sailplanes and motor gliders bearing his distinctive name and
style flying well into the 1980s.
Fauvel's designs were similar in concept to those of
his countryman, Rene Arnoux. The two even collaborated on a tailless
patent in 1930. Fauvel also favoured the absence of sweepback, dihedral,
and washout. Fauvel's wings did incorporate considerable taper, however,
to the extent that wing tips were almost pointed. He did not favour wing
tip rudders, but leaned toward single or double vertical fins and rudders
on the after part of the wing centre section.
Fauvel produced a number of powered and unpowered
models during the 1930s, with varying degrees of success. The A.V.2 was a
powered glider that enjoyed limited success in 1933. The engine was
detachable and the wheels could be replaced by a skid for test flights of
that configuration. The unpowered A.V.3 was tested during the summer of
1933, and demonstrated excellent flying qualities. The A.V.10 of 1934-1935
was the most successful in many respects, having been exhibited at the
Paris Aero Salon and subsequently receiving the first certificate of
airworthiness ever awarded to a tailless aircraft in France. The
two-passenger airplane was powered by a 75-hp Pobjoy engine which, in June
1936, carried the unique aircraft to an altitude of 23,500 feet.
Fauvel's pre-World War II designs were not financial
successes, but his theories on longitudinal stability in tailless aircraft
were sound. After the war's end his name was associated with a series of
tailless gliders and homebuilt airplanes that had great popular appeal.
The imaginative Horten brothers, Walter and Reimar,
approached the ideal of the flying wing with their own powered aircraft of
the 1930s and 1940s. All of the Horten craft were innovative and were
distinguished by experimental shapes and diverse control systems. Their
impact on flying wing design was significant, and special consideration
will be given to Horten designs of World War II in a later page.
Three Horten gliders of the pre-war years were
interesting precursors of their World War II designs. The first of these,
the 1931 Ho I sailplane, consisted of a wing with a small cockpit canopy
in the centre section. The craft was constructed of wood with fabric
covering and incorporated a central, fixed landing skid. Having no
vertical or tail surfaces, the Ho I was controlled by separate ailerons
and elevators located at the trailing edge of each wing panel. Yaw control
was obtained by the use of brake flaps above and below the leading edges
near the wing tips.
The aircraft was licensed too late to enter the Rhon
Gliding competition of 1934. The Hortens towed it from Bonn to
the Wasserkuppe in the Rhon mountains in western Germany. Unfortunately,
Reimar damaged the skid on landing, putting the glider out of commission
for awhile. Finally, in frustration, the brothers salvaged the metal
hardware and burned the glider after only seven hours of flight time,
convinced that a better design was possible.
Another wooden airplane, the Ho II, followed in 1934.
Improvements over the Ho I included trailing edge sweep back and a tandem
wheel undercarriage with retractable nosewheel and faired rear wheel. Two
trailing edge surface controls were linked so that the outboard controls
primarily gave longitudinal control, and the inboard surface provided
lateral control. Wing tip brake flaps were fitted for yaw control. First
flown as a glider in 1934, the Ho II was equipped in 1935 with an 80-hp
Hirth HM 60R engine that was submerged in the wing and drove a pusher
propeller through an extension shaft. Hanna Reitsch, the famed German
woman test pilot, flew the Ho II on November 17, 1938. Stability and
control were considered marginal in some respects, but the aircraft could
not be stalled or spun by any combination of control movements. The
diminutive Hanna Reitsch described the cockpit as only possible for
athletes, while the arrangement and operation of the retractable landing
gear were considered as only possible for long-armed pilots.
Spurred on by a less than enthusiastic endorsement, but
with some official interest, the Hortens constructed the more elaborate Ho
III in 1938. Also designed as a sailplane, the Ho III resembled the Ho II
but had increased span and aspect ratio and was of mixed construction, the
centre section being of welded steel tubes with plywood covering, and the
outer sections being of wood. The trailing edge of each wing half carried
three control surfaces to replace the two of the Ho II, the inner surface
being used as a landing flap and the outer surfaces acting differentially
as ailerons and together as elevators. Directional control was provided by
tip-mounted drag rudders.
A second version of the design, the Ho IIIB, was built,
and considerable experimental work was done with the two sailplanes. Dive
flaps were tried on both upper and lower centre section surfaces;
automatic flaps were installed on the under surfaces to limit maximum
diving speed; and the wing tips were rigged to rotate for lateral control.
Other versions of the aircraft were built; the Ho IIIC was fitted with a
small additional wing set forward of the main wing; the Ho IIID was built
as a powered glider with a propeller whose blades could be folded to
reduce drag during gliding.
The Ho HID was built as a powered glider and featured a propeller whose
blades could be folded to reduce drag during unpowered flight. The
propeller is shown in the folded position. Outer wing sections are
With the beginning of World War II, the Hortens
eventually attracted the government interest they required to continue
their flying wing developments. Their efforts, like those of other
believers in tailless aircraft in Germany, England, and the United States,
turned to finding a wartime use for such an airplane.
The Horten brothers can be viewed as purists in their
experiments with tailless airplanes in that all of their designs were
distinguished by the total absence of any vertical control surfaces. Also
dedicated to the idea of tailless aircraft but a firm believer in the
requirement for vertical surfaces for directional stability and control,
was their countryman, Alexander Lippisch.
Few serious designers of tailless airplanes could claim
the lasting impact on modern aircraft design that Lippisch had with his
development of the delta wing, which is found in many military airplanes
of the 1980s and in the Concorde and TU-144 supersonic transports. As a
Berlin schoolboy of 14, Lippisch had the good fortune to witness a flight
demonstration by Orville Wright in September 1909. Thus inspired, he
followed the accounts of Dunne's and Etrich's experiments with inherent
stability, and after military service during World War I, applied his
interest to glider design. His first tailless glider was built in 1921, by
Gottlob Espenlaub, the German glider enthusiast who would later
collaborate with the Swiss designer Alexander Soldenhoff on his designs
The Lippisch-Espenlaub E2 was the first of over 50
swept-wing, tailless designs produced by Lippisch over the next three
decades. Though this first effort was less than impressive, it at least
was a starting point from which Lippisch began serious, systematic
development of tailless designs. In 1924, he was designated Director of
the Aeronautical Department of the RhonRossitten-Gesellschaft (RRG, which
later became the German Research Institute for Soaring Flight).
Designer Alexander Lippisch (right) poses with builder Gottlob Espenlaub
(left) by their E2 glider of 1921. Plates at each wing tip were drooped to
provide directional stability. Test flights were not impressive.
With limited resources at his disposal, Lippisch chose
an unconventional, step-by-step method of developing his designs, testing
the original concept first as a flying model, then as a man-carrying
glider, and finally as a powered aircraft. Lippisch considered this
approach would produce results in less time and with less expense than a
wind tunnel research program. From this design philosophy evolved two
famous series of tailless aircraft-the Storch (stork) and the Delta.
The Lippisch Storch II o f 1927-1928 had free swing end plate rudders at
each wing tip. The craft suffered from poor directional stability, and
subsequent versions had solid end plates with adjustable rudders.
Between 1927 and 1932, eight Storch aircraft were
designed by Lippisch, all of them high-wing monoplanes with sweepback. In
1926, a succession of large, free-flying models of various configurations,
including canards and the "flying plank" design later adopted by Fauvel in
France, led to the Storch I experimental glider, first test flown in 1927
by Bubi Nehring. Lack of aileron effectiveness was evident in this and the
Storch II and III that followed. The ailerons were redesigned to
approximate the form of the Zanonia seed and Igo Etrich's Taube. Etrich
himself recommended the configuration to Lippisch; his faith in the
principle was reaffirmed when the 1929 Storch IV glider demonstrated
impressive stability and control characteristics with Gunther Gronhoff at
Development work on the Storch
series was temporarily interrupted
in 1928 when Lippisch collaborated with Fritz von Opel and the rocket
manufacturer Sander in performing rocket-powered flights of some Lippisch
tailless models. These successful experiments were followed by a manned
flight of a rocket-powered tail-first glider, the Ente (duck). Although
these experiments also met with moderate success, Lippisch returned to his
original interests in 1929. These experiments, and subsequent research on
the basic principles of rocket propulsion, provided the foundation for
later projects with rocket-propelled aircraft in the late 1930s.
In 1929, the Storch V appeared equipped with a small,
8-hp DKW engine for Lippisch's first attempt at powered flight with the
Storch series. Following successful test flights by Gronhoff, a public
demonstration of the Storch V was made at Tempelhof Airfield at Berlin in
October 1929, with the expectation of obtaining some government financial
backing. None came, but the transatlantic pilot Captain Herman Kohl
expressed interest in the idea of a tailless aircraft for flights across
the Atlantic. With this order in hand, Lippisch stopped work on the
Storch VI and began the design of what would eventually become the
renowned Delta series. Lippisch later worked on three more versions of the
Storch; the Storch VII, powered by a 24-hp engine, won a
prize for the first 300 km overland flight of a tailless aircraft when
Gronhoff flew the aircraft from the Wasserkuppe to Berlin in 1931
in 1 hour, 55 minutes. The Storch VIII was a privately financed
craft that could be flown either with or without tail surfaces attached.
The Storch IX training glider appeared in 1933, and was
successful enough to prompt two variations, the IX a and b.
Lippisch's methodical, step-by-step experiments had
been quite successful with the Storch series, but the Storch
was merely a foundation for further efforts to build a pure, all-wing
aircraft. From the Storch, with its sweptback leading and trailing
edges, came the Delta, also a sweptback wing but with one essential
difference: the trailing edge, from wing tip to wing tip, was a straight
line. This triangular wing allowed a thick midsection, with the potential
for storing all loads inside the wing.
Following his customary routine, Lippisch proceeded
from drawing to flying model to full-scale glider, and finally in June
1931, the powered Delta I was flown on the Wasserkuppe. Again, Gunther
Gronhoff's test flights were so successful that another Templehof
demonstration was conducted; and again, the Lippisch aircraft was clearly
a success, with accounts of Gronhoff's acrobatic skill with the
revolutionary airplane appearing in the press in Europe and the United
States.' Unfortunately, no financial backing materialized.
The Delta I of 1931 is shown in company with two Junkers G31 transports.
The Delta I was powered with a 30-hp Bristol Cherub engine. Trailing-edge
hinged surfaces at the outer section of the wing were used as ailerons;
inner surfaces served elevators
The Delta I is shown in flight over Templehof Airport at Berlin in
For the next several years, Lippisch, serving with the
RRG (in 1933 reorganized under the title Deutsche Forschungsanstalt
fur Segelflug [DFS, German Research Institute for Soaring Flight]),
produced dozens of designs for tailless aircraft; some never left the
drawing board, and some made it to the model stage. Others, like the
Delta, eventually flew and underwent countless modifications as tests
revealed deficiencies in stability and control. The Delta series
progressed through the Delta IVC, at which point the series designation
was changed to DFS 39. The DFS 40, or Delta V, was the last of the
series to fly, in 1939.
As the decade came to a close and Germany prepared for
war, Lippisch transferred to the Messerschmitt Company in January 1939,
where he again became involved in the application of rocket propulsion to
Interest in tailless aircraft was not confined to
western Europe and England during the period between the wars. Designers
in the Soviet Union demonstrated an appreciation for the idea and an
understanding of the benefits and problems associated with the design. The
idea even found some expression in Poland, though they met with extremely
limited success there.
In the years between the wars, the Soviet Union
provided a congenial atmosphere for a series of important experiments with
designs for tailless aircraft. Even in the difficult economic conditions
of the 1920s, the Bolsheviks sought to demonstrate their air-mindedness
through aeronautical researching the K-4, the first civilian aircraft ever
manufactured in series production in the Soviet Union. In 1934, he turned
his efforts to a tailless airplane for the military. The aircraft that
evolved, the K-12, was a strange looking craft with a trapezoidal wing,
wing tip rudders, and trailing edge elevators and ailerons. It was
supposed to be a three-place bomber with gunners' positions at the front
The BOK-a (above) was a Product of' the Experimental Design Bureau. It was
supposedly built as a flying scale model for the much larger Kalinin K-12
(below), but showed little resemblance to that airplane.
The fabric skin of the K-12, nicknamed Firebird, was painted a garish red
for effect. The unusual airplane was billed as the world's first tailless
The K-12 first flew in 1936 and demonstrated
satisfactory flying qualities. Nicknamed Firebird by its designer,
the airplane made its first public appearance at Tushino Airport on August
18, 1937, sporting a paint scheme that was at least unusual. The K-12 went
into series production in 1938, and the Russians claimed it was the first
tailless bomber in the world. Successful though it may have been, however,
it came to the usual end for tailless aircraft; the reasons were only
stated differently; Kalinin, at the peak of his career, "fell victim to
the arbitrary and vicious procedures arising from Stalin's cult of
personality." He was placed under arrest and his design bureau was
Since Kalinin's death in 1938, there has been little
tangible evidence of interest in the USSR in tailless aircraft until the
emergence of the delta wing following World War II. The Soviets seemed to
have experienced the usual problems with stability and control encountered
by their contemporaries in western Europe and America, and on the surface
do not appear to have made any extraordinary breakthroughs in flying wing
Eastern European interest in tailless aircraft design
during the pre-war period was not limited to the Soviet Union. There are
several examples of such activity in Poland. As early as 1923, tailless
designs appeared, initially at the First Polish Glider Contest. Of the
amateur designs, two were tailless. One of these, the Zabus
(froggy), the work of Captain
Franciszek Jach, seemed reasonably conventional in concept, lacking only a
vertical fin and rudder. Appearances were deceiving, however, since the
control system was decidedly unconventional, even for a tailless glider.
The elevator control surface was operated by the pilot's feet, and each
aileron by a separate hand lever! The machine, flown by its designer,
crashed after 16 seconds in the air on its only flight.
Also entered in the contest was the Dziaba, an aircraft
so bizarre in concept and appearance that had it not been seriously
damaged by wind while being carried to the starting point, a mishap on its
maiden flight would not have been a surprise. It featured a
variable-camber wing with a small horizontal stabilizer mounted in front
of the wing on two rods. The stabilizer was operated by the
camber-changing mechanism inside the wing. There were no vertical surfaces
initially, although apparently two were added later. The pilot altered
wing camber differentially, or on both sides of the wing together, to
control the aircraft's roll or pitch. There was no
landing gear; the aircraft was strapped to the pilot, who was supposed to
run until airborne. The glider was repaired before the end of the contest,
but the lack of wind precluded any attempt to fly.
The futuristic JN 1, named after its designer Jaroslaw
Naleszkiewicz, had a successful maiden flight in July 1932. It was a true
tailless craft, with trailing-edge elevators and ailerons, and wing tip
mounted vertical fins and rudders, both of which could be deflected to act
as air brakes. Despite its success in the air, the project went no
Gustaw Mokrzycki's PZL22 was described as unorthodox
when it was completed and readied for flight in 1934. Mokrzycki, Professor
of Flight Mechanics and Aircraft Building at the Warsaw Technical
University, was a farsighted individual with a flair for the
unconventional. Influenced by Lippisch's tailless aircraft from the late
twenties, Mokrzycki designed a small wooden aircraft, which wind tunnel
tests predicted would have good stability and flying qualities.
The airplane had a delta wing, upon which was situated
a plywood nacelle with open cockpit. Control surfaces consisted of elevons
and a vertical rudder hinged at the rear of the nacelle, with an American
Menasco B-6 six-cylinder air-cooled engine and fixed undercarriage. Due to
its unconventional nature, flight tests were not officially sanctioned and
the plane was relegated to obscurity.
The dearth of successful tailless designs in Poland was
not due to a lack of highly skilled aircraft designers who were willing to
create imaginative designs. Rather, a combination of factors was involved:
adverse political and economic circumstances, lack of wide support for its
aircraft industry, bureaucratic indifference and resistance to the
unorthodox (the latter situation was common in even the most highly
As Hill, Lippisch, and the Hortens spearheaded serious
activity involving tailless aircraft in Europe during the 1920s and 1930s,
interest in the United States was minimal until the 1930s, when the idea
became quite fashionable. Designs by the dozens appeared; some flew once,
some often, many not at all. None attracted the requisite financial
support or had the market appeal to qualify as successful commercial
ventures. Not until the end of the decade did a design appear with all the
necessary elements: sound design, government interest and support, and a