Instrument landing system

“ On this model aircraft the electrical signal system of the landing gear consists of green and red lights to indicate the down and up positions respectively. These lights are operated by a contact switch located on the landing gear proper rather than on the latch. Inasmuch as the electrical contact is not directly at the latches, it is possible when the landing gear is out of adjustment, for the green signals to light when the landing gear is in a down position even though the latches are not fully engaged. ”

“ It included gyroscopes, ion sensors, solar sensors, star sensors, a sextant, manual controls, the Kaskad orientation system, and “the radio rendezvous equipment which jointly with the radio equipment of the transport ship provides for measuring the relative parameters of motion.” Rendezvous and docking was the SOUD’s most complicated operating mode. The system had several layers of redundancy. [36] Attitude control and main propulsion systems were brought together in Salyut 6 to form the Integrated Propulsion System (Russian acronym ODU) . ”

“ Nevertheless, in spite of these hazards it is remarkable how many machines, even when shot down with some vital part out of commission, in many cases falling several thousand feet, have righted themselves before reaching the ground and made a safe landing, due to the precision and accuracy of construction with regard to lateral and longitudinal balance. And all in all, judging from the wonderful records already made by aeroplanes, even the single-motored machine is very reliable. ”

“ A powerful engine driving a winch will be necessary to raise these heavy wires from the ground, although of course the lift of the airship will assist in this. Secondly, the lowering of passengers and cargo will not be easy as the ship will not be rigidly secured. This, however, can probably be managed when experiments have reached a further stage, and at present the system may be said to present distinct possibilities. ”

“ Recently there has been a great deal of discussion in Engineering and other journals regarding the comparative merits of the aeroplane system and the hélicoptère. Some condemn both systems and pin their faith to flapping wings. It has been contended that the screw propeller is extremely wasteful in energy, and that in all Nature neither fish nor bird propels itself by means of a screw. As we do not find a screw in Nature, why then should we employ it in a machine for performing artificial flight? ”

“ You could have a square hole in the center; then the disk launching device would have a square shaft, rotated by an engine or a motor. As the speed built up, the cambered disk would ride up the shaft and free itself, rising vertically, with the jets taking over the job of whirling the cambered section.
“The lift would be terrific, far more than any normal aircraft. I don’t believe any human being could take the G’s involved in a maximum power climb; they’d have to use remote control. When it got to the desired altitude, your disk could be flown in any direction by tilting it that way. ”

“ Of course, when an aviator is lost in the fog or above the clouds he needs to use all the instruments on board to find his position. For that purpose drift instruments are mounted on aircraft; those tell how much the air-currents, which have the same effect on aircraft as the tide has on a boat, have driven him off his course. A compass indicates the direction in which he is travelling, and other instruments show him whether his machine is climbing, diving, or “banking”; the aneroid barometer indicates the altitude. ”

“ It is fixed in such a way that the engineer shall have the power, by means of cords which connect it with the car, of inclining it in any direction, so as to steer the machine towards the point selected for landing, precisely as a hawk uses its wings when it pounces on the fugitive it seeks to make its prey. There is a horizontal screw fixed to the machine, which is intended to communicate the motion of translation, or in other words, to give the engineer power to direct the course of the aerial ship. ”

“ When the machine is once perfected, it will not require a railway track to enable it to get the necessary velocity to rise. A short run over a moderately level field will suffice. As far as landing is concerned, the aerial navigator will touch the ground when moving forward, and the machine will be brought to a state of rest by sliding on the ground for a short distance. ”

“ One of the difficulties of landing is owing to the fact that even training-machines cannot land at a slower speed than thirty-five miles an hour. If the wheels of the aeroplane, when they first touch ground, do not skim over the surface of the field, the machine is liable to “nose in” and turn a somersault. Indeed, that is why the pusher type of training-machine, with the propeller in the rear of the pilot, is being abandoned for the tractor machine, which has the propeller in front. If an accident does occur with a tractor the engine does not “climb your back.” ”

“ The reduction of “head resistance” and the “streamlining” of the airplane have received their goodly share of attention and experiment. To-day the airplane fuselage is carefully streamlined, but the landing chassis beneath it creates a good deal of resistance to motion. Probably this problem will be solved by devising a landing chassis which, after the [167] machine has arisen from the ground, can be drawn up inside the body, and let down again to make a landing, but this is another important question which is not yet worked out in the airplanes of the present time. ”

“ The flying machine, built, apparently, almost entirely of metal, was driven by an engine said to weigh, with fuel and water, about 25 lbs., the supporting surface from tip to tip being 12 or 14 feet. Starting from a platform about 20 feet high, the machine rose at first directly in the face of the wind, moving with great steadiness, and subsequently wheeling in large curves until steam was exhausted, when, from a height of 80 or 100 feet, it shortly settled down. ”

“ By means of the gauge and spring drums they are extended automatically when the machine is not in swift flight. When the craft has made an ascent and attained a speed sufficient to create a vacuum under the dipping or front edge of the planes, the suction or reverse pressure on the gauges allows the drums to reel in the extension surfaces. When in full motion, as these come in, speed is naturally increased and all the extensions are housed securely beneath or over the main section of the wing. ”

“ They were operated by a pendulum-controlling device to be inclined so as always to maintain the vessel on a level keel rather than cause her to depart therefrom. When I came to try this combination out in practice I found hand control of the horizontal rudders was sufficient. If vessels with this system of control have a sufficient amount of stability, they will run for hours and automatically maintain both a constant depth and a level keel, without the depth-control man touching either the hydroplane or horizontal rudder control gear. ”

“ A part of the aërodrome should be given over to aëroplanes, used for the bringing of mails and urgent freight from places distant from the terminal. Heavier-than-air machines, in fact, will be the veins leading to the great arteries of the world's air routes, operated by dirigibles. A strong searchlight, for the guidance of aëroplane pilots flying in fog, might be necessary. Given improved landing facilities, means might be found for them to coast down the searchlight, if the ground away from it were invisible. ”

“ The torsion wing device for lateral control and steering, which he claimed in his patent application, abandoned after his death, now constitutes a very important feature of every flying machine. His planes for fore and aft control, introduced by Maxim, are also in general use to-day. The principle of load distribution, which he greatly prized for diminishing stress and adding stability, has still to be evaluated by practical test in larger craft than any now in operation. The closed hull, for comfort and economy at high speed, is at present popular with many designers. ”

“ Now the higher the aspect ratio the greater should be the efficiency. Air escaping by the sides represents loss, and the length of the sides should be kept short. A broader aerofoil means a steeper angle of inclination, less stability, unnecessary waste of power, and is totally unsuited for a model—to say nothing of a full-sized machine. ”

“ 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 airship, flying-machine, aerostat, or whatever we please to call it, must not merely move, but also lift itself. Neither a ship 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 matter of control-surface design it is interesting to note the contrast between the preferences of English and German designers. In almost all German machines the ailerons, elevators, and rudder are balanced, i.e. surface is disposed each side of the hinge-axis, this applying to the small Albatross scouts and to the large machines of the Gotha class; while in this country few examples of this practice occur. The reason for the balancing of controls lies in the desire to reduce the manual strain on the pilot to a minimum ”

“ It is true that tacking is impossible, so that our sailing balloons must always run before the wind: but they possess this great advantage over marine sailing craft, that by varying their altitude they may always be able to find a favorable wind. This implies adequate altitude control, which is one of the problems not yet solved for lighter-than-air flying machines: but when it has been solved we shall go far toward attaining a dirigible balloon without motor or propeller ”

“ Then, there were double control wires, running from the levers to the rudder and the elevating planes, so that, if one wire broke (a thing that has caused many an aviator’s death) another would take its place.
For starting the machine from the seat—without having to have some one whirl the propeller till the engine was going—there was an electrical motor, which was a sort of boy of all work. For, when it was through its work as a motor, it became a dynamo, and filled up storage-batteries which worked the big electrical search-light, for use when the machine was flying at night. ”

“ This principle, however, affords a safer means of navigating than the orthopter type, because the blades of such an instrument can be forced through the air with infinitely greater speed than beating wings, and it devolves on the inventor to devise some form of apparatus which will permit the change of pull from a vertical to a horizontal direction while in flight. ”

“ For those days, the landing demands were rather exacting; the machine should be able to rise without damage from long grass, clover, or harrowed land, in 100 yards in a calm, and should be able to land without damage on any cultivated ground, including rough ploughed land, and, when landing on smooth turf in a calm, be able to pull up within 75 yards of the point of first touching the ground. It was required that pilot and observer should have as open a view as possible to front and flanks, and they should be so shielded from the wind as to be able to communicate with each other. ”

“ A machine such as is described in the Signal Corps’ specifications would record the solution of all the difficulties in210 the way of the heavier-than-air airship, and, in fact, finally give mankind almost as complete control of the air as it now has of the land and the water. ”

“ The theory with such craft is that their sustaining planes, either by a telescopic system, or by some process of reefing, are built so that they can be expanded or contracted at the will of the pilot. Thus in rising, when a machine is required to ascend with a minimum run forward across the ground, a large area of lifting surface would be exposed; and at the moment of alighting, also, when it was desired that a machine should make its contact with the ground at the slowest possible speed, a maximum of plane surface would be employed. ”

“ Design became standardised, though not perfected. The domination of the machine may best be expressed by contrasting the way in which machines came to be regarded as compared with the men who flew them: up to 1909, flying enthusiasts talked of Farman, of Bleriot, of Paulhan, Curtiss, and of other men; later, they began to talk of the Voisin, the Deperdussin, and even to the Fokker, the Avro, and the Bristol type. ”

“ As the machine nears the earth it is caused to change the angle of flight by the control mechanism so that it will dart upwardly at an angle, or downwardly, and thus enable the pilot to sail to another point beyond where he may safely land. This changing the course of the machine so that it will glide upwardly, means that the incidence of the planes has been changed to a positive angle. ”

“ The lander/rover system needs extensive machine intelligence capability. Technology requirements are greatest for a long-range rover operating independently in the absence of continuous communications with the main orbiting spacecraft or with Earth. This capability is highly desirable, since without it the operational demands placed on other mission elements ? such as the subsatellites for ground-to- orbit Titan uplink or powered air vehicles necessary for sample and system component transport rapidly may become unmanageable. ”