Part 19 (1/2)

The reason of this is not far to seek. The difficulties attending the creation of a successful flying-machine are immense, some unique, not being found in aquatic and terrestrial locomotion.

In the first place, the airs.h.i.+p, flying-machine, aerostat, or whatever we please to call it, must not merely move, but also lift itself.

Neither a s.h.i.+p nor a locomotive is called upon to do this. Its ability to lift itself must depend upon either the employment of large balloons or upon sheer power. In the first case the balloon will, by reason of its size, be unmanageable in a high wind; in the second case, a breakdown in the machinery would probably prove fatal.

Even supposing that our aerostat can lift itself successfully, we encounter the difficulties connected with steering in a medium traversed by ever-s.h.i.+fting currents of air, which demands of the helmsman a caution and capacity seldom required on land or water. Add to these the difficulties of leaving the ground and alighting safely upon it; and, what is more serious than all, the fact that though success can be attained only by experiment, experiment is in this case extremely expensive and risky, any failure often resulting in total ruin of the machine, and sometimes in loss of life. The list of those who have perished in the search for the power of flight is a very long one.

Yet in spite of these obstacles determined attempts have been and are being made to conquer the air. Men in a position to judge are confident that the day of conquest is not very far distant, and that the next generation may be as familiar with aerostats as we with motor-cars. Speculation as to the future is, however, here less profitable than a consideration of what has been already done in the direction of collecting forces for the final victory.

To begin at the beginning, we see that experimenters must be divided into two great cla.s.ses: those who pin their faith to airs.h.i.+ps lighter than air, _e.g._ Santos Dumont, Zeppelin, Roze; and those who have small respect for balloons, and see the ideal air-craft in a _machine_ lifted entirely by means of power and surfaces pressing the air after the manner of a kite. Sir Hiram Maxim and Professor S. P. Langley, Mr.

Lawrence Hargrave, and Mr. Sydney Hollands are eminent members of the latter cult.

As soon as we get on the topic of steerable balloons the name of Mr.

Santos Dumont looms large. But before dealing with his exploits we may notice the airs.h.i.+p of Count Zeppelin, an ingenious and costly structure that was tested over Lake Constance in 1900.

The balloon was built in a large wooden shed, 450 by 78 by 66 feet, that floated on the lake on ninety pontoons. The shed alone cost over 10,000.

The balloon itself was nearly 400 feet long, with a cylindrical diameter of 39 feet, except at its ends, which were conical, to offer as little resistance as possible to the air. Externally it afforded the appearance of a single-compartment bag, but in reality it was divided into seventeen parts, each gas-tight, so that an accident to one part of the fabric should not imperil the whole.

A framework of aluminium rods and rings gave the bag a partial rigidity.

Its capacity was 12,000 cubic yards of hydrogen gas, which, as our readers doubtless know, is much lighter though more expensive than ordinary coal-gas; each inflation costing several hundreds of pounds.

Under the balloon hung two cars of aluminium, the motors and the screws; and also a great sliding weight of 600 lbs. for altering the ”tip” of the airs.h.i.+p; and rudders to steer its course.

On June 30 a great number of scientific men and experts a.s.sembled to witness the behaviour of a balloon which had cost 20,000. For two days wind prevented a start, but on July 2, at 7.30 P.M., the balloon emerged from its shed, and at eight o'clock commenced its first journey, with and against a light easterly wind for a distance of three and a half miles. A mishap to the steering-gear occurred early in the trip, and prevented the airs.h.i.+p appearing to advantage, but a landing was effected easily and safely. In the following October the Count made a second attempt, returning against a wind blowing at three yards a second, or rather more than six miles an hour.

[Ill.u.s.tration: _The air-s.h.i.+p of M. Santos-Dumont rounding the Eiffel Tower during its successful run for the Henri Deutsch Prize._]

Owing to lack of funds the fate of the ”Great Eastern” has overtaken the Zeppelin airs.h.i.+p--to be broken up, and the parts sold.

The aged Count had demonstrated that a petroleum motor could be used in the neighbourhood of gas without danger. It was, however, reserved for a younger man to give a more decided proof of the steerableness of a balloon.

In 1900 M. Henri Deutsch, a member of the French Aero Club, founded a prize of 4000, to win which a compet.i.tor must start from the Aero Club Park, near the Seine in Paris, sail to and round the Eiffel Tower, and be back at the starting-point within a time-limit of half-an-hour.

M. Santos Dumont, a wealthy and plucky young Brazilian, had, previously to this offer, made several successful journeys in motor balloons in the neighbourhood of the Eiffel Tower. He therefore determined to make a bid for the prize with a specially constructed balloon ”Santos Dumont V.” The third unsuccessful attempt ended in disaster to the airs.h.i.+p, which fell on to the houses, but fortunately without injuring its occupant.

Another balloon--”Santos Dumont VI.”--was then built. On Sat.u.r.day, October 19th, M. Dumont reached the Tower in nine minutes and recrossed the starting line in 20-1/2 more minutes, thus complying with the conditions of the prize with half-a-minute to spare. A dispute, however, arose as to whether the prize had been actually won, some of the committee contending that the balloon should have come to earth within the half-hour, instead of merely pa.s.sing overhead; but finally the well-merited prize was awarded to the determined young aeronaut.

The successful airs.h.i.+p was of moderate proportions as compared with that of Count Zeppelin. The cigar-shaped bag was 112 feet long and 20 feet in diameter, holding 715 cubic yards of gas. M. Dumont showed originality in furnis.h.i.+ng it with a smaller balloon inside, which could be pumped full of air so as to counteract any leakage in the external bag and keep it taut. The motor, on which everything depended, was a four-cylinder petrol-driven engine, furnished with ”water-jackets” to prevent over-heating. The motor turned a large screw--made of silk and stretched over light frames--200 times a minute, giving a driving force of 175 lbs. Behind, a rudder directed the airs.h.i.+p, and in front hung down a long rope suspended by one end that could be drawn towards the centre of the frame to alter the trim of the s.h.i.+p. The aeronaut stood in a large wicker basket flanked on either side by bags of sand ballast. The fact that the motor, once stopped, could only be restarted by coming to earth again added an element of great uncertainty to all his trips; and on one occasion the mis-firing of one of the cylinders almost brought about a collision with the Eiffel Tower.

From Paris M. Dumont went to Monaco at the invitation of the prince of that princ.i.p.ality, and cruised about over the bay in his balloon. His fresh scheme was to cross to Corsica, but it was brought to an abrupt conclusion by a leakage of gas, which precipitated balloon and balloonist into the sea. Dumont was rescued, and at once set about new projects, including a visit to the Crystal Palace, where he would have made a series of ascents this summer (1902) but for damage done to the silk of the gas-bag by its immersion in salt water and the other vicissitudes it had pa.s.sed through. Dumont's most important achievement has been, like that of Count Zeppelin, the application of the gasolene motor to aeromobilism. In proportion to its size this form of motor develops a large amount of energy, and its mechanism is comparatively simple--a matter of great moment to the aeronaut. He has also shown that under favourable conditions a balloon may be steered against a head-wind, though not with the certainty that is desirable before air travel can be p.r.o.nounced an even moderately simple undertaking. The fact that many inventors, such as Dr. Barton, M.

Roze, Henri Deutsch, are fitting motors to balloons in the hopes of solving the aerial problem shows that the airs.h.i.+p has still a strong hold on the minds of men. But on reviewing the successes of such combinations of lifting and driving power it must be confessed, with all due respect to M. Dumont, that they are somewhat meagre, and do not show any great advance.

The question is whether these men are not working on wrong lines, and whether their utmost endeavours and those of their successors will ever produce anything more than a very semi-successful craft. Their efforts appear foredoomed to failure. As Sir Hiram Maxim has observed, a balloon by its very nature is light and fragile, it is a mere bubble. If it were possible to construct a motor to develop 100 horse-power for every pound of its weight, it would still be impossible to navigate a balloon against a wind of more than a certain strength. The mere energy of the motor would crush the gas-bag against the pressure of the wind, deform it, and render it unmanageable.

Balloons therefore must be at the mercy of the wind, and obliged to submit to it under conditions not always in accordance with the wish of the aeronaut.

Sir Hiram in condemning the airs.h.i.+p was ready with a subst.i.tute. On looking round on the patterns of Nature, he concluded that, inasmuch as all things that fly are heavier than air, the problem of aerial navigation must be solved by a machine whose natural tendency is to fall to the ground, and which can be sustained only by the exertion of great force. Its very weight would enable it to withstand, at least to a far greater extent than the airs.h.i.+p, the varying currents of the air.

The lifting principle must be a.n.a.logous to that by which a kite is suspended. A kite is prevented from rising beyond a certain height by a string, and the pressure of the wind working against it at an angle tends to lift it, like a soft wedge continuously driven under it. In practice it makes no difference whether the kite be stationary in a wind or towed rapidly through a dead calm; the wedge-like action of the air remains the same.

Maxim decided upon constructing what was practically a huge compound kite driven by very powerful motors.