The concept of a V shaped empennage was first envisaged in 1910 by two Germans from Wallsee, Hopfenwieser and Höfinger. They began construction of a fuselage with such a tail unit. There does not seem to be any evidence that any aircraft incorporating this device was completed or any tests carried out, the idea being abandoned and forgotten.
In the the late 1920’s, Jerzy Rudlicki (https://en.wikipedia.org/wiki/Jerzy_Rudlicki) was exploring ways by which a gunner defending an aircraft from the rear could be improved. Rudlicki, who was completely unaware of Hopfenwieser’s and Höfinger’s work, began to pursue the idea of an empennage consisting of two inclined elements in place of a conventional tail. In the course of preliminary investigations of the system various configurations, including A, W and M forms, were studied, which showed the V layout to be the most promising. In 1930, at the Warsaw Aerodynamic Institute, extensive comparative wind-tunnel tests of conventional Rudlicki V-tail began. These fully confirmed the designer’s expectations. The results of these tests combined with detailed design investigations revealed that as well as improvements to the field of fire, the system had better efficiency, aerodynamic advantages and a reduction of 35% of the dead weight of the tail structure.
All this encouraged E.Plage & T.Laśkiewicz to test the empennage in the air. In early 1931 work commenced on an experimental of Polish built Hanriot H.D.14 serial no. 30.83 which incorporated the Rudlicki V-tail. The aircraft became the first aircraft in the world to fly with what is popularly known as a ‘butterfly tail’. Władysław Szulczewski began flight trials in early summer 1931.
Factory tests proved very successful and completely trouble free and upon completion the Hanriot was transferred to the I.B.T.L in Warsaw. There it was comprehensively evaluated by the Institute’s pilots Kazimierz Kaźmierczuk and Col. Jerzy Kossowski. Neither of the pilots found any difficulty in converting to the Rudlicki V-tail system and all reports stressed the handling characteristics of the aircraft were comparable or superior to those of standard machine, controllability in flight and on the ground being particularly good.
Despite this, the Department of Aeronautics, for reasons known only to itself, did not approve the invention. When Lublin built the R-XIX incorporating the Rudlicki V-tail the Department reprimanded the factory and instructed it to abandon all further work on the system.
Although dismissed in Poland, Rudlicki’s invention attracted attention abroad. The RAE was engaged in extensive research into improving spin recovery characteristics, particularly the Bristol Bulldog, and showed considerable interest in Rudlicki’s V-tail. Experiments with models were carried out at the RAE’s Free Spinning Tunnel and Rudlicki was invited to Britain to discuss the the issues involved.
Initial experiments suggested that there was no particular merit in the system as an anti-spinning device, but A.V.Stephens, who conducted the research, noted that their outcome was not entirely conclusive. Another series of test was devised but not carried out.
Some research was also carried out in France, Russia, Germany and Italy, the Rudlicki-tail was installed on the French Blériot-Spad 992 and Mauboussin research biplanes and experimental conversions of the Russian R-5 and U-2 (Po-2) biplanes.
In adapting the Rudlicki V-tail to the Hanriot, the same rudder pedals and control column were retained by introducing a special transmission box which enabled the pilot to fly the machine employing the same operations he would use in controlling a conventional aircraft. Backward and forward movements of the control column operated the moveable tail surfaces together as elevators. Lateral movements controlled the ailerons in the ordinary way. The differential gearing in the transmission box permitted the pilot to operate the moveable tail surfaces differentially by normal movements of the rudder pedals. The transmission box itself was small and very light, carried in the rear of the fuselage near the tail. From each side of the box two axles connected by leavers extended to the moveable tail surfaces. By means of the levers the mechanism was connected to the normal system of control, one lever being connected to the control column and the other to the rudder bar. Movement of the first lever caused the surfaces to move in the same direction, while movement of the latter caused them to move differentially.
Dipl. Ing Zygmunt Zakrzewski, managing director of the Lublin works, impressed with the results on the modified Hanriot H.D.14and the widespread international interest in the Rudlicki, approved Rudlitcki’s ideas concerning a V-tailed version of the R-XIII, which offered the best solution of defence against attack from the rear. As the Department of Aeronautics showed no enthusiasm for the project, development was undertaken by the company as a private venture. Extensive wind-tunnel tests with scale models embodying V and A-type configurations of the tail surfaces were conducted at the Warsaw Aerodynamic Institute and the V-tail eventually chosen as the more efficient.
In late 1931 the R-XIII prototype, serial 56.1, was returned to Lublin for a complete overhaul an brought up to full Lotnictwo Wojskowe standards. The factory management decided to rebuild this machine at its own expense to serve as the R-XIX prototype. The R-XIX flew in the summer of 1932, and after comprehensive air tests at the factory, mainly conducted by Władsław Szulczewki, arrived unannounced in Warsaw to be demonstrated at the I.B.T.L. Col Kossowski was present and immediately offered to take the aeroplane for a flight. He then proceeded to put the aircraft through its paces with breath-taking aerobatics and on landing expressed a very favourable opinion on the design.
This was to infuriate the the Department of Aeronautics who severely reprimanded Kossowski for flying the aircraft without permission and for expressing a positive opinion which did not coincide with with that of the Department. Zakrzewski was summoned to learn off the Department’s displeasure and the factory was punished by being fined for failing to deliver the overhauled R-XIII to the LW on time. Further flights of the R-XIX were strictly forbidden and on the Department’s order the offending tail was sawn off and the airframe sent back by rail to Lublin.
Thank you awesome research.
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