Part 11 (2/2)
I told them only to take care of the cable, because the balloon would settle down by herself before long I was congratulating erous position I had not counted on the wind
A breeze in about six or eight e sail, then a crash, and--the anchor was loose again
It tore through the trees, flinging limbs and branches about likethe chilass
”On I went; I came near another farm; shouted out for help, and told the e tree close by The anchor was soon ain filled the half-empty balloon like a sail, there was a severe strain on the cable, then a dull sound, and a severe concussion of the basket--the cable, strange fatality, had broken, and the anchor, one I was now carried on in a straight direction towards the sea, which was but a short distance ahead The anchor being lost I gave up all hope I sat down resigned in the car, and prepared for the end All at once I discovered that a side current was drifting round, and was dashi+ng along at a fearful rate, knocking down stone fences and breaking everything it came in contact with in its wild career By-and-by the knocks beca over a cultivated country, and the car was, as it were skies I saw a thick hawthorn hedge at so towards it That wase”
CHAPTER XXI THE COMING OF THE FLYING MACHINE
In the early nineties the air shi+p was engaging the attention ofimportant strides in the hands of Mr Maxi the case, premises that a motive power has to be discovered which can develop at least as ht as a bird is able to develop He asserts that a heavy bird, with relatively soose--carries about 150 lb to the horse pohile the albatross or the vulture, possessed of proportionately greater winged surface, can carry about 250 lbs per horse power
Professor Langley, of Washi+ngton, working contemporaneously, but independently of Mr Maxi aro-round”), thirty feet long, applying screw propellers He used, for theloads of only two or three pounds, and, under these circuht carried was at the rate of 250 lbs per horse power His iard to these trials are that one-horse poill transport a larger weight at twenty er at fortypressure of the air on a plane le of inclination to a horizontal path is reater than would result froiven by Newton, while, whereas in land or marine transport increased speed is maintained only by a disproportionate expenditure of poithin the liher speeds are more economical of power than the lower ones”
This Mr Maxi, in his oords, that birds obtain the greater part of their support byforith sufficient velocity so as to be constantly resting on new air, the inertia of which has not been disturbed Mr Maxim's trials were on a scale comparable with all his mechanical achieve ar out a circle, the circumference of which was 200 feet To the end of this arar-shaped apparatus, driven by a screw, and arranged in such a le These planes were on a large scale, carrying weights of from 20 lbs to 100 lbs With this contrivance he found that, whatever push the screw communicated to the aero-plane, ”the plane would lift in a vertical direction from ten to fifteen times as much as the horizontal push that it received frole at which the plane was set, and the speed at which the apparatus was travelling through the air” Next, having determined by experiht, Mr Maxi the requisite motor
”I constructed,” he states, ”two sets of co enerator of peculiar construction, the greater part of the heating surface consisting of small and thin copper tubes For fuel I e that he was then experi a spread of over 100 feet Labour, skill, and reat task undertaken, and it was not long before the giant flying , was coht was 7,500 lbs The screw propellers were nearly 18 feet in diaines were capable of being run up to 360 horse power The entire machine was mounted on an inner railway track of 9 feet and an outer of 35 feet gauge, while above there was a reversed rail along which the in to run so soon as with increase of speed it commenced to lift itself off the inner track
In one of the latest experiments it was found that when a speed of 42on the upper track, and revolving in the opposite direction fro about 1,000 feet, an axle tree doubled up, and immediately afterwards the upper track broke away, and thethose on board a sensation of being in a boat”
The experiment proved conclusively to the inventor that aeffect should be considerably greater than the weight of the ine was the , the steaine was for the purposes of aerial locoine, the construction of a navigable air shi+p became vastly more practicable
Still, in Sir H Maxiate the air by hter than the air have come, practically, to the end of their tether,” while, on the other hand, ”those who seek to navigate the air with machines heavier than the air have not even made a start as yet, and the possibilities before thereat indeed”
As to the assertion that the aerial navigators last mentioned ”have not even made a start as yet,” we can only say that Sir H Maxim speaks with far too much modesty His own colossal labours in the direction of that ht, which he considers to be alone feasible, are of the first ione, exhaustive Had his experiations of the proper form of the screw propeller his name would still have been handed down as a true pioneer in aeronautics His work, however, covers far wider ground, and he has, in a variety of ways, furnished practical and reliable data, which uide to every future worker in the sa the same problem, first studied the principle and behaviour of a well-known toy--the model invented by Penaud, which, driven by the tension of india-rubber, sustains itself in the air for a few seconds He constructed over thirtyfro leading to horizontal flight” His best endeavours at first, however, showed that he needed three or four feet of sustaining surface to a pound of weight, whereas he calculated that a bird could soar with a surface of less than half a foot to the pound He next proceeded to steam-driven models in which for a tiht, which, in practice, always exceeded his calculation; and it was not till the end of 1893 that he felt himself prepared for a fair trial At this ti between nine and ten pounds, and he needed only a suitable launching apparatus to be used over water The model would, like a bird, require an initial velocity iave hi were supplied by a houseboat ain by many difficulties, it was not till after repeated failures and the lapse of many months, when, as the Professor himself puts it, hope was low, that success finally caht was accomplished in the presence of Dr Bell, of telephone fa is a brief epitome of the account that this accomplished scientist contributed to the colu machine, built, apparently, alh, with fuel and water, about 25 lbs, the supporting surface fro froh, thewith great steadiness, and subsequently wheeling in large curves until steaht of 80 or 100 feet, it shortly settled down The experiment was then repeated with silass of water ht each time, which lasted for a minute and a half, exceeded half a mile, while the velocity was between twenty and twenty-fiveit 'up hill' A yet ht of another nature was being courageously attempted at this time Otto Lilienthal, of Berlin, in i apparatus which he operated himself, and hich he could float down from considerable elevations ”The feat,” he warns tyros, ”requires practice In the beginning the height should be e, or the ill soon show that it is not to be trifled with” The inventor co his first atteh, and subsequently increasing this height to two and a half metres, frorass plot Later he launched hih, when he sailed to a distance of over 250 yards, and this tiht acco and with gradually increased extent and elevation of flight have gained full control over the apparatus, it is not in the least dangerous to cross deep and broad ravines It is a difficult task to convey to one who has never enjoyed aerial flight a clear perception of the exhilarating pleasure of this elastic round loses its terrors, because we have learned by experience what sure dependence may be placed upon the buoyancy of the air”
As a co:--”We have to record the death of Otto Lilienthal, whose soaring ht, suddenly tilted over at a height of about 60 feet, by which ust 9th, 1896” Mr O
Chanute, CE of Chicago, took up the study of gliding flight at the point where Lilienthal left it, and, later, Professor Fitzgerald and others Besides that invented by Penaud, other aero-planefellow, and Lawrence Hargrave, of Australia, the subsequent inventor of the well-known cellular kite These models, for the most part, aim at theflight of a bird
The theoretical solution of the saley in a raph, entitled ”The Internal Work of the Wind” By painstaking experiment with delicate instruments, specially constructed, the Professor shows that wind in general, so far fro, as was commonly assumed, mere air put in motion with an approximately uniform velocity in the saular in itsmade up, in fact, of a succession of brief pulsations in different directions, and of great coues, if of sufficient amplitude and frequency, would be capable, by reason of their own ”internal work,” of sustaining or even raising a suitably curved surface which was being carried along by the main mean air strea” Lord Rayleigh, discussing the sa the air cannot beuniformly and horizontally Then co currents? Lord Rayleigh has frequently noticed such currents, particularly above a cliff facing the wind Again, to quote another eminent authority, Major Baden-Powell, on an occasion when flying one of his own kites, found it getting to so high an angle that it presently rose absolutely overhead, with the string perpendicular He then took up a heavy piece of wood, which, when tied to the string, began to rise in the air He satisfied hi uptake of the air
But, again, Lord Rayleigh, lending support to Professor Langley's argu may be the non-uniforer than the lower, and it is e of two adjacent air streams, different in velocity, to maintain itself in air without effort on its own part
Lord Rayleigh, proceeding to give his views on artificial flight, declares themachine to be the proble a plane surface to be falling vertically at the rate of fourhorizontally at the rate of twenty ht have been supposed that the horizontal motion would make no difference to the pressure on its under surface which the falling plane must experience
We are told, however, that in actual trial the horizontalplane, and it is this fact on which the possibility of natural and artificial flight depends”
Ere this opinion had been stated by Lord Rayleigh in his discourse on ”Flight,” at the Royal Institution, there were already at work upon the aero-plane a small army of inventors, of whom it will be only possible in a future chapter to mention some Due reference, however, should here be made to Mr W F Wenhaht forwhether h paid a high tribute As far back as 1866 Mr Wenham had published a paper on aerial locomotion, in which he shows that any iht be ie the necessary length of wing as a series of aero-planes, a conception far in advance of many theorists of his time
But there had been developments in aerostation in other lines, and it is time to turn froht and the theory or practice of soaring, to another i the air--the parachute This aerial ation of the air with a reliability never before realised Professor Baldwin, as he was terland in the su a series of exhibitions from the Alexandra Palace with a parachute of his own invention, which, in actual performance, seems to have been the most perfect instrument of the kind up to that time devised It was said to be about 18 feet in diameter, whereas that of Garnerin, already mentioned, had a dia to its being thus inadequately ballasted; for it was calculated that its enormous size would have served for the safe descent, not of one man, but of four or five Baldwin's parachute, on the contrary, was reckoned to give safe descent to 250 lbs, which would include weight of man and apparatus, and reduce the ulti 8 feet The parachute was attached to the ring of a small balloon of 12,000 cubic feet, and the Professor ascended, sitting on aof rope, which did duty for a car
Mr Thoated the mechanics of the contrivance, estimated that after a drop of 16 feet, the upward pressure, a to over 2 lb per square foot, would act on a surface of not less than 254 square feet There was, at the tireat distance which the parachute fell before it opened, a complete delusion due to the fact that observers failed to see that at theupward