flying wings 1870 to 1920
flying wings in Europe
tailless aircraft in the USA
German flying wings
British flying wings
Japanese flying wings
American flying wings in WW2
the first Northrop flying wing
Northrop flying wings in WW2
Northrop: towards the bombers
Northrop flying wing bombers
flying wings 1950s and beyond
secret Soviet flying wings

European 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 injuries himself.

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 reports.

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 the designer.

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 flying reptile.

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 stall/spin accidents.

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 attack.

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 and range.

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 missing.

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 the controls.

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 September 1931.

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 tailless aircraft.

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 and rear.

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 bomber

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 disbanded.

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 design.

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 further.

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 industrialized countries).

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 market.