Hugo Byttebier - The Rise of the Flying Machine

Towards the end of 1893 he began to make calculations for an aircraft using a 2 hp engine which, by acting on the wings, would propel the plane forward and, he hoped, would thereby convert a downward glide into a horizontal flight.

He thereupon built a steam engine of 2 hp weighed only 20 kg (44 lbs) but later (in 1895) he replaced it by a motor using carbonic acid that also was able to produce 2 hp and was even lighter, giving Lilienthal the opportunity to build a new glider with oscillating wingtips as proposed in his book of 1889. But he was never able to flight-test a powered glider and was thus spared the disappointment of realizing that it would not be possible to achieve horizontal flight with only 2 hp.

During 1894 Lilienthal became world famous. The January issue of L’Aéronaute carried an article which stated that “the whole French Press is agog. The papers are full of articles claiming that the great problem of aerial navigation has at last been solved”. “But L’Aéronaute ” commented wryly that “Mr Lilienthal’s apparatus is a dirigible parachute and the parachute is an old device”. Perhaps a touch of envy may be detected here, although it is also true that Lilienthal had followed the proposal of the “dirigible parachute” made by de La Landelle in 1884.

That same year, a French doctor, Emile Veyrin who was an air enthusiast and who possibly understood German, received a letter from Lilienthal advising him and his compatriots to start researching flight according to his teachings, but nobody in France was willing to become a pupil of Lilienthal’s, and it was not until much later that his teachings were to have any effect in France. In February 1895 Veyrin published an article about the “Flying Man”, in which he deduced that Lilienthal must have been a scientist, a craftsman and a gymnast and in this he was very near the truth.

In order to soar better, more wing surface was needed, so Lilienthal built two biplane gliders (during 1895) one of 194 sq ft and a second of 269 sq ft because he had found that monoplanes with greater wing area were difficult to control by the shifting of body weight alone. In an article published in James Means’ Aeronautical Annual of 1896, Lilienthal referred to these biplanes as having “twice the bearing capacity but on account of its small dimensions this apparatus obeys much better the changes in the centre of gravity”.

But Lilienthal did not fully try out these biplanes, which were probably the first flying biplanes in aviation history, because he was beginning to consider other means of controlling his aircraft.

In the article published in the Aeronautical Annual for 1896, already referred to, Lilienthal wrote: “I came to the conviction that an increase in the size of the wings or the utilising of still stronger winds, which would lengthen the journey in the air, would necessitate something being done to perfect the steering and to facilitate the management of the apparatus.” Lilienthal was wrong in this because to perfect the steering would not necessarily facilitate the management of a flying machine.

On 17 April 1896 he wrote to James Means: “I am now engaged in constructing an apparatus in which the position of the wings can be changed during flight in such a way that the balancing is not effected by changing the position of the centre of gravity of the body... It will increase the safety.” In fact the system by which the position of the wings could be changed during flight was developed to its ultimate perfection by the Wright brothers six years later, but it did not lead to an increase in safety.

Lilienthal was about to start a new phase in his progress towards human flight. But the course he was entering upon would have led to a series of struggles, frustrations and difficulties, from which he was fortunately spared by his death at a fateful moment in his career. On 9 August 1896, Lilienthal was again in the Rhinower Mountains to carry out some more practice in sailing flight. According to Paul Beylich, his ever-present trusted assistant, it was a day of gusty winds, but Lilienthal possessed the confidence that comes from long experience. During his fourth gliding flight that day, when he was sailing about 50 ft above the ground, the craft suddenly seemed to stand still in the air. Becoming aware of the danger of a stall, Lilienthal moved his legs so as to give the plane an inclination downwards and to allow it to regain flying speed but it was too late and instead of inclining gently, the plane suddenly dived almost vertically and crashed, breaking Lilienthal’s back. His last words before he died the following day are said to have been “Sacrifices must be made” ( Opfer müssen gebracht werden ), though there is no mention of this prior to 1930. He was the first martyr of that period in the history of the conquest of the air.

Several sources have recorded that the glider in which Lilienthal crashed was an experimental one in which the fixed horizontal tail had been replaced by a movable one actuated by the pilot through a string attached to his head. Lilienthal would thus have transformed his glider from one that was inherently stable to one of controlled balance and this may have caused the accident.

Percy Pilcher, an Englishman who was Lilienthal’s most brilliant disciple, wrote in 1897: “Herr Lilienthal came to grief through deserting his old method of balancing.”

Percy Pilcher (From 1895 to 1899)

Lilienthal’s most brilliant follower was the British inventor and pioneer aviator Percy Sinclair Pilcher. Born in January 1867, after seven years in the Royal Navy from the age of thirteen, Pilcher undertook an apprenticeship in a Glasgow shipbuilding firm, subsequently being appointed as assistant lecturer at Glasgow University in 1891. After his appointment Pilcher started flying experiments, inspired by newspaper reports of Lilienthal’s successful gliding flights.

Pilcher built his first glider early in 1895. He stated that he purposely finished his own machine before going to see Lilienthal so as to get the greatest advantage from any original ideas he might have. This first glider was named the “Bat” and was a monoplane with a pronounced dihedral, weighing 45 lbs and with a wing area of 150 sq ft.

In its first form the “Bat” was therefore defective in lateral stability and, having no horizontal tail, in longitudinal stability as well. According to the historian of aviation and biographer of Pilcher Philipp Jarrett, the “Bat” was not completely finished in April 1895 when Pilcher travelled to Germany for a visit to Otto Lilienthal.

Lilienthal must have been delighted to meet such an appreciative and intelligent pupil and, on his second visit in June 1896, Pilcher was allowed to fly one of the biplane gliders Lilienthal was then using. Lilienthal taught him a great deal and inculcated in him the necessity for inherent stability, a lesson that Pilcher never forgot. Back in Britain he reduced the dihedral angle of the “Bat” and added a fixed horizontal tailplane.

Pilcher began is first flying test on 12 September 1895 starting from the slopes of a grass hill on the banks of the Clyde near Cardross in Scotland. For his second test, in order to be able to take off from low ground he devised a system whereby a team of horses going at a gallop towed the glider into the air against the wind so that he was able to make gliding flights of up to a minute without the need to continually climb hills as Lilienthal was doing.

He then thought of installing an engine and built a second glider which he called the “Beetle” because, with its broad square wing, it looked like one. The wing of the “Beetle” had no dihedral at all and covered 170 sq ft but it was heavy at 80 lbs when empty. There was no light engine to be had at that time and the “Beetle” was not much of a success as a glider. Pilcher found he was unable to control it in the air, because this had to be done by shifting his body just as Lilienthal manoeuvred his gliders. He thereupon returned to his earlier “Bat” and, after several modifications, carried out various successful flights.