Two somewhat similar experiments are alluded to in M. G. de la Landelle's "Aviation," published in 1863, but are too briefly described to give much of an idea as to the kind of apparatus employed; he says:
Paul Guidotti, an artist-painter, sculptor and architect, who was born in Lucca in 1569, constructed wings of whalebone covered with feathers, and made use of them several times with success. Determining to exhibit his discovery, he took flight from an elevation, and sustained himself pretty well in the air for a quarter of a mile, but soon becoming exhausted, he fell upon a roof, and his thigh-bone was broken.
I might also cite the article from the Malaga newspaper, the Courier of Andalusia, which was republished in several French journals in March, 1863 stating that a peasant of the neighborhood, named Francisco Orujo, was said to have sailed in the air a distance of one league with artificial wings in less than fifteen minutes; but why multiply examples? It is better to deduce from these occurrences, some of which are abundantly authenticated, useful conclusions concerning the insufficiency of man's muscular power, and concerning the sustaining power of an inclined plane.
The writer has been thus far unable to find in other publications fuller accounts of the last two experiments mentioned, but it is a significant fact that the greater number of the experimenters who are said by tradition to have actually succeeded in floating for a short distance on the air, were men living in warm climates, where the soaring varieties of birds are much more numerous and more easily observed than in variable and colder climates. This suggests the inference that these experimenters had been watching the soaring birds, sailing upon fixed wings in every direction, and endeavored to imitate their evolutions. With the aid of the wind they may have attained a glimmer of success, but they failed in every instance for lack of accurate knowledge of what constitutes the science of the birds. Elsewhere than in warm climates the soaring birds are so few, they so frequently have to resort to flapping, that those who have not seen them sailing about for hours upon fixed, extended wings, deny even the possibility of such a performance, and only think of wings as oscillating surfaces; and so when, in 1842, Henson patented his flying machine, the proposal to obtain support from the fixed surfaces of an aeroplane was hailed by many as a new and happy idea.
A top view of Henson apparatus is shown by fig. 37. It consisted of an aeroplane of canvas or oiled silk stretched upon a frame made rigid by trussing, both above and below. Under this surface a car was to be attached containing a steam-engine, its supplies and the passengers. The apparatus was to be propelled by two rotating wheels, acting upon the air after the manner of a windmill. Back of these was a tail, also covered with canvas or oiled silk, stretched upon a triangular frame, and capable of being expanded or contracted at pleasure, or moved up and down for the purpose of causing the machine to ascend or to descend. Under the tail a rudder was placed for steering the machine to the right or to the left, and above the main aeroplane a sail or keel-cloth was stretched, as shown, between the two masts which rose from the car, in order to assist in maintaining the course. The apparatus was to sail with its front edge a little raised so as to obtain the required support or lift from the air, and was to be started from the top of an inclined plane, in descending which it was to attain a velocity sufficient to sustain it in its further progress the steam-engine being only designed to overcome the head resistance when in full flight.
Fig. 37. -- HENSON -- 1842.
Henson's patent indicates that he believed the correct proportions to be about 2 sq. ft. of supporting surface to each pound of weight, this being considerably in excess of the proportion of the large soaring birds, and that the motor required was about at the rate of 20 H.P. per ton of weight. His general design evidences careful thought and possesses some excellent features, but the form of his aeroplane was crude and its equilibrium especially was deficient. Henson stated in his patent:
The following are the dimensions of the machine I am making, and which will weigh about 3000 lbs. The surface of the planes on either side of the car will measure 4,500 sq. ft., and the tail 1,500 more, with a steam-engine (high pressure) of 25 to 30 H.P.
Scaled from the patent drawings the intended dimensions of the main aeroplane appear to have been about 140 ft. , long in the direction of motion, by about 32 ft. in width this being considerably larger than the great aeroplane that Mr. Maxim has been lately constructing in England.
Henson did not realize his intention, for Mr. F. W. Brearey, Honorary Secretary of the Aeronautical Society of Great Britain, says in an article upon flying machines, published in Popular Science Review in 186916, in describing the Henson experiments:
The fact is the machine was never constructed, for after two abortive attempts to manufacture models at the Adelaide Gallery, which should represent the dimensions before named, he rejoined his friend (Stringfellow) at Chard, and the two together commenced their experiments under a variety of forms. ... However, in 1844, they commenced the construction of a model; Henson attending chiefly to the wood or framework and Stringfellow to the power, and after many trials adopted steam. This model, completed in 1845, measured 20 ft. from tip to tip of wing, by 3 1/2 ft. wide, giving 70 square feet sustaining surface in the wings, and about 10 ft. more in the tail. The weight of the entire machine was from 25 to 28 lbs.... An inclined plane was constructed, down which the machine was to glide, and it was so arranged that the power should be maintained by a steam engine, working two four bladed propellers each 3 ft. in diameter at the rate of 300 revolutions per minute.
A tent was erected upon the downs, 2 miles from Chard, and for seven weeks the two experimenters continued their labors. Not, however, without much annoyance from intruders. In the language of Mr. Stringfellow: "There stood our aerial protégé in all her purity--too delicate, too fragile, too beautiful for this rough world; at least those were my ideas at the time, but little did I think how soon it was to be realized. I soon found, before I had time to introduce the spark, a drooping in the wings, a flagging in all the parts. In less than ten minutes the machine was saturated with wet from a deposit of dew., so that anything like a trial was impossible by night. I did not consider that we could get the silk light and rigid enough. Indeed the framework was altogether too weak. The steam engine was the best part. Our want of success was not for want of power or sustaining surface, but for want of proper adaptation of the means to the end of the various parts."
Many trials by day, down inclined wide rails, showed a faulty construction, and its lightness proved an obstacle to its successfully contending with the ground currents.
The above has been given verbatim, because of the importance of the experiments. Stated in plainer terms, it means that the machine was deficient in stable equilibrium for out-of-door experiments; that "ground currents" or little puffs of wind would destroy the balance, and that in falling to the ground it would get more or less injured. That the experimenters, annoyed at the presence of spectators at these mishaps, endeavored to test their machine at night, with still less success, and finally gave it up in disgust. Mr. LBrearey then continues:
Shortly after this Henson left England for America, and Mr. Stringfellow, far from discouraged, renewed his experiments alone. In 1846 he commenced a smaller model for indoor trial, and, although very imperfect, it was the most successful of his attempts (an illustration from a photograph is given); the sustaining planes were much like the wings of a birch They were lo ft. from tip to tip, feathered at the back edge, and curved a little on the under side. The plane was 2 ft. across at the widest part; sustaining surface, 17 sq. ft.; and the propellers were 16 in. in diameter, with four blades occupying three-quarters of the area of the circumference, set at an angle of 60°. The cylinder of the steam-engine was 3/4 m. diameter; length of stroke, 2 in.; bevel gear on crank-shaft, giving 3 revolutions of the propeller to 1 of the engine. The weight of the entire model and engine was 6 lbs. and with water and fuel it did not exceed 6 1/2 Ibs.
The room which he had available for the experiments did not measure above 22 yds. in length, and was rather contracted in height, so that he was obliged to keep his starting wires very low. He found, however, upon putting his engine in motion that in one-third the length of its run upon the extended wire the machine was enabled to sustain itself; and upon reaching the point of self-detachment it gradually rose until it reached the farther end of the room, where there was a canvas fixed to receive it. Frequently during these experiments it rose after leaving the wire as much as 1 in 7.
Stringfellow then went to Cremorne Gardens with the two models, but found the accommadations no better than at home. It was found that the larger model (Henson's) would run well upon the wire, but failed to support itself when liberated. Owing to unfulfilled engagements as to room, Mr. Stringfellow was preparing for departure, when a party of gentlemen, unconnected with the gardens, begged to see an experiment and finding them able to appreciate his endeavors, he got up steam pretty high and started the small model down the wire When it arrived at the spot where it should leave the wire, it appeared to meet with some little obstruction and threatened to come to the ground, but it soon recovered itself and darted off in as fair a flight as it was possible to make, to a distance of about 40 yds., farther than which it could not proceed.
Having now demonstrated the practicability of making a steam engine fly and finding nothing but a pecuniary loss and little honor, this experimenter rested for a long time satisfied with what he had effected.
It is evident that, taught by experience, Mr. Stringfellow had obtained greater stability in the smaller model. The aeroplane was shaped like the wings of a bird, slightly curved on the underside and feathered at the back edge, so that the elastic yielding of the feathers might automatically regulate the fore and aft stability, like the back fold in the paper aeroplane which has been described; but the equilibrium was still insufficient for experiment out-of-doors, and the important problem of safely coming down was not solved at all, for to prevent breakage the apparatus had to be caught in a canvas fixed to receive it.
The sparrow-hawk, whose excursion has been described (fig. 36) solved this last problem by simply tilting himself back and opening his wings wide so as to stop his headway by increased air resistance. This possibly might be done with a full-sized apparatus mounted by an operator, but was scarcely practicable in a small model. To mitigate this difficulty Mr. Stringfellow increased the sustaining surface, so that it was 2.61 sq. ft. per pound, and therefore might act like a parachute, but this largely increased the "drift," and required more power, so that water and fuel could only be provided for a very brief flight, and the machine cannot fairly be said to have "demonstrated the practicability of making a steam engine fly."
Mr. Stringfellow took the matter up again in 1868, and made further experiments with a somewhat different apparatus, which will be described in due course.
The next proposal for an aeroplane was that of Aubaud, in 1851, which is shown in fig. 38. It provided for a number of supporting planes, above which rotating screws were to furnish ascending power, while vibrating wings were to propel. The car containing the motor was to he beneath the planes, and equipped with legs or tubes containing compressed air, in order to ease off the shocks which might be encountered in alighting
Fig. 38. -- AUBAUD-- 1851.
M. Aubaud seems to have reasoned that in order to secure safety in coming down, it was necessary to arrange matters so that the whole weight, or nearly the whole weight of the apparatus, could be sustained by screws when about alighting. This same general idea will he found to crop out in a number of subsequent proposals by inventors, who have believed that in order to come down safely it is necessary to design a machine which has enough power to start up by itself on level ground. This, of course, requires much more power than it only horizontal flight is provided for, and handicaps the inventor in an experimental machine.
The writer has been unable to ascertain whether Aubaud ever tested his apparatus experimentally. It seems clear that if he did, he must have become aware that no motor then known was sufficiently light in proportion to its energy to raise his machine into the air with screws especially as he actually increased the ascending resistance by placing planes beneath the screws, so that the latter would not only have to sustain the weight, but also to overcome the vertical air pressure resulting from the movement. He advanced a meritorious proposal, however, by dividing the sustaining surface into several planes, an arrangement which we shall find (in describing Mr. D. S. Brown' s experiments) to add materially to the stability; but even with this feature the apparatus, as shown in the figure, is deficient in equilibrium, and would have come to grief many times if it had been experimented with.
The succeeding year Michel Loup proposed another form of aeroplane, which is shown both in plan and in side elevation in fig. 39. It is described both by M. Dieuaide and M. Tissandier as consisting of a supporting plane propelled by four rotating wings, and provided with a rudder, also with legs beneath the car carrying wheels upon which the machine might roll upon alighting on the ground, an arrangement subsequently proposed again by many inventors.
Fig. 39. -- LOUP-- 1852.
The writer has been unable to find any record of experiments tried with this apparatus (which is chiefly here figured to show the wheeled feet), and it seems difficult to conceive of its successful operation.
In 1856 Viscount Carlingford patented both in England and France the aeroplane shown in fig. 40, and resembling in outline a falcon gliding downward with partially closed wings. In the center was a car or chariot, described by the inventor as follows:
The aerial chariot in form is something in the shape of a boat, extremely light, with one wheel in front and two behind, having two wings, slightly concave, fixed to its sides, and sustained by laths of a half hollow form pressing against them, and communicating their pressure through the body of the chariot from one wing to the other, and supported by cords, whose force, acting on two hoops nearly of an oval shape, hold the wings firmly in their position.
Fig. 40. -- CARLINGFORD -- 1856.
A tail can be raised and lowered at pleasure by means of a cord.
The chariot is drawn forward by an "aerial screw" in front thereof, "which screws into the air at an elevation of 45°, similar to the bird's wing; and is turned by means of a winch acting on three multiplying wheels." This screw "is known as the Carlingford screw; the blades of this screw become more straight as they approach the center, or, in other words, their edges become more direct toward the center.... When a certain altitude is attained the chariot may go several miles, perhaps 50 or 60, as it were, upon an inclined plane of air."
A novelty consisted in the mode proposed for starting the chariot. It was proposed to suspend it by ropes between two poles, and then allow it (by drawing a trigger suddenly) to fall upon the air and to be drawn "forward with great velocity by the falling of the weight in front;" a method which we have seen to have been subsequently adopted by M. Trouvé in starting his bird. If the inventor was thoroughly assured beforehand of the stability of his apparatus at all angles of incidence, this would be an elegant method of getting under way, but it would be somewhat awkward if there was any miscalculation about the position of the center of pressure. The writer has found no record of any experiments with the Carlingford apparatus.
16Popular Science Review, vol. 8, p. 1
|List of Illustrations||Table of Contents||Index|