Читать книгу The Rise of the Flying Machine - Hugo Byttebier - Страница 36

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.

In the spring of 1896 Pilcher built his third glider, the “Gull”. In a bold move, the wing area was enlarged to 300 sq ft and the weight was kept to a low 55 lbs, but Pilcher had gone too far in lowering the wing loading and the “Gull” was nearly unmanageable in any kind of wind.

The “Gull” did not last long either and was replaced by a smaller version of it, named the “Hawk”, which became Pilcher’s most successful machine. The wing area was reduced to 180 sq ft and it weighed 50 lbs. The need for inherent stability was kept firmly in mind and when Lilienthal crashed to his death in August 1896, Pilcher, who had heard about the redesigned movable tail, offered what was probably the correct diagnosis of Lilienthal’s accident, which was probably due to the abandonment of inherent stability in favour of positive control.

The “Hawk” was such a success that Pilcher again began to look around for an engine capable of overcoming the force of gravity, the glider’s source of power. “The object of experimenting with soaring machines” wrote Pilcher at that time, “is to enable one to have practice in starting and alighting and controlling a machine in the air. They cannot possibly float horizontally in the air for any length, of time, but to keep going must necessarily lose in elevation. They are excellent schooling machines and that is all they are meant to be, until power, in the shape of an engine working a screw propeller... is added.”

Pilcher, at that time heard rumours of an engine in the US which gave 1 hp for a weight of 15 lbs, but which never materialized. So, like most of the pioneers of that decade, Pilcher decided that he would have to build an engine himself. He designed a two-cylinder horizontally-opposed engine which he calculated to give 4 hp for a weight of 44 lbs and, after achieving some very good flights, especially one in June 1897 during which he covered 750 ft under perfect balance, he started to build a powered aeroplane.

In 1897 Pilcher had formed a company in partnership with W. G. Wilson, and in November had begun corresponding with Chanute. In January 1898, whilst he was working on his engine, he wrote to Chanute that he intended to make “a machine like one of your multiple sail ones”. Chanute replied that Pilcher was welcome to make a multiple-wing machine, but he ruled the biplane out because Chanute did not wish to incur Herring’s wrath.

Pilcher thereupon designed a project for a quadruplane, but finally decided on a triplane, as favoured by Chanute, including the stabilizing tail at the rear which was fixed according to Lilienthal’s directions. But before he could finish his engine so as to have the triplane ready for tests in flight, Pilcher’s fate overtook him.

In the midst of a drive for raising funds to help defray the cost for the powered machine, Pilcher decided to make a demonstration flight in the “Hawk” in the presence of a select group of visitors, among whom were Major B. F. S. Baden Powell, secretary of the Aeronautical Society and later its president, who had come down from London for that purpose.

On 30 September 1899 the visitors were present and Pilcher was anxious not to disappoint them and, although the weather was unfavourable with gusty winds and light showers, he decided to go ahead. His take-off system at that time consisted in having his plane towed by means of a tackle that multiplied the speed of the two horses that drew it. A first attempt was successful but the line broke. On the second attempt one of the guy wires holding the tail in position broke and the “Hawk” dived down out of control and crashed.

Pilcher died two days later of the injuries he had sustained, the second victim of heavier-than-air machine experiments and the first victim of structural failure during flight. He was also the first of several airmen who suffered accidents which resulted from risk taken in adverse circumstances so as not to disappoint spectators who had come to witness a flight.