The National Airship.

New Zealand Graphic, Volume XLV, Issue 18, 2 November 1910, Page 42

The National Airship.

The “ Morning Post” Lebaudy Dirigible, which has just crossed the Channel according to the cable of October 27.

THE dirigible balloon ordered on behalf of the “Morning Post” National Airship Fund, and which, according to the cable received on Thursday successfully crossed the channel and arrived at Aidershot was built by MM. Paul and Pierre Lebaudy, the famous French airship constructors, at their works at La Villette and Moisson io the plans of their engineer, M. Julliot. The airship, which has been constructed to meet the requirements of the Army, to whom it will be presented when it nas passed its tests, belongs to the type known as ••»emi-rigid”; that is to say. on the one hand, the rigidity of the exterior form of the gas-bag is obtained by the use of ballonets and ventilators; on the other hand, the gas-bag carries immediately beneath it a combination of two kinds of planes, namely, horizontal and vertical planes, both movable and fixed, which enable the balloon to be steered in anv direction, and which ensures stability. The combination of fixed planes forms a rigid under-frame, which divides the suspension (that is, the cords and wire cables bv which the car is hung from the gas-bag)' into two parts: the upper part between the under-frame and the gas-bag is short, and, if the gas-bag becomes limp and loses its shape, cannot break or tear the envelope through uneven and excessive tension; the lower part of the suspension between the under-frame and the car. that is to say, between two rigid bodies, can be of ' considerable length without risk of uneven and excessive strain, no matter what may be tne variation in the pressure of the gas and in the shape of the gas-bag. The essential parts of the “dirigible” are: (1) The gas-bag or envelope. (2) The fixed and movable planes. (3) The car. (4) The suspension or hanging gear. (5) The motors. 1 (6) The propellers. (7) Various accessories. The envelope is 103 metres (337 ft. lOin.) in length, 12.02 metres (39ft. 54in.) in diameter, and has a cubic capacity of 10,000 metres (353,165.8 cubic feet). In the bows it tapers to a sharp point, and is egg-shaped at the stern. It is composed of panels of waterproof canvas, consisting of two tissues of cotton and two layers of vulcanised indiarubber, superposed alternately, these panels being glued and sewn together. The outer tissue is dyed an inactinie yellow to diminish the injurious effects of light on

the rubber, while the interior layer of rubber makes the envelope more gasproof, and preserves the cotton tissue from the injurious effects that might be caused by impurities in the gas. The gas-bag is filled with hydrogen gas. the purest and lightest obtainable, with a lifting force of 1,175 grammes to the cubic metre; in other words, 100 cubic feet of gas lift between 7.33 and 7.34 lb. Thanks to the care with which it is constructed, it loses considerably less than 1 per cent, of its volume in gas every 24 hours. To be precise, the loss of hydrogen is only .6 per cent. The envelope is provided in its lower surface with two valves of large diameter, ■which allow of the evacuation of hydrogen, more particularly while the balloon is in flight. These valves are automatic; that is to say, they open as soon as

the pressure of the gas in the envelope becomes excessive. Further, they can be worked by hand. There is, in addition, a valve at the top of the gas-bag, which is usually closed by a diaphragm. Tins valve can only be worked by hand, and allows the balloon to be entirely emptied. The two lower valves are placed in the stern of the gas-bag to avoid all risk of ignition from the motors. In cases of emergency two long ripping panels, one fore, one aft, glued and only lightly sewn to the rest of the fabric, allow the balloon to be completely deflated in a few seconds. By means of four observation holes, each covered with glass and framed with aluminium, the condition of the interior of the balloon can be inspected visually when it is at rest in its shed. Water and metal manometers show the pressure of the gas in the envelope at any given moment.

Ballonets and Their Value. There are inside the gas-bag tlj.re,e ballonets that can be filled with air under pressure, so that when the gas contracts or is lost the pressure within the envelope, which preserves the shape and rigidity of the'gas-bag, may 'be maintained. These ballonets have a capacity of over 2,500 cubic metres, or rather more than a quarter of the capacity of the balloon. Their size is an important factor in enabling the airship to travel

at a height of from 6,000 to 6,500 feet, an altitijffe at which it would be far beyond the range of an enemy’s fire. The ballonets fore and aft of the central (one have an additional purpose. By forcing air into one or other of them the pilot can change or regulate the longitudinal equilibrium of the airship so as to make it fly point upwards or downwards at a certain angle, as he wishes. Each ballonet is provided with a safety-valve, which opens automatically and allows the air to escape at a (pressure slightly inferior to that of the gas. When need arises these valves can be worked by hand.

The Planes. The movable planes, which are intended to seer the airship both horizontally and vertically, consist of—(1) A vertical plane articulated round an almost vertical axis. The word “almost” is used advisedly, since, in case of accident, the rudder falls into a neutral position in wholly automatic fashion. This is the rudder in the ordinary sense of the word. It is placed immediately below the gas-bag at the stern of the rigid under-frame, which transmits its action directly to the dirigible. (2) Two horizontal planes with rounded angles, articulated round the same horizontal axis which is fitted to the under-frame below the centre of the bal-

loon. By deflecting these planes the pilot can" make the airship rise in a direction parallel to itself without throwing out ballast, and he can in the same way make it descend. Similar axes are fitted to the under frame, both fore and aft, to carry like planes which allow the whole balloon to be inclined for the purpose of rising or descending. The trials will show the value of these pairs of horizontal rudders, and will decide whether it is advisable to keep both pairs or either of them. The fixed planes, which, like the movable planes, are built of steel tubes with canvas stretched over them, are both horizontal and vertical. The Car. The car is solidly built of steel tubes, and is incombustible. It is relatively short, and only touches the ground with a single point. This point, which is very strongly constructed of pyramidal steel tubes, is placed in the bow, and when the airship is at anchor serves as a pivot on which the whole balloon may be swung round in any direction, so as to avoid being taken sideways by the wind. In the case of the car bumping along the ground, a second and shorter point of similar pyramidal construction in the stern comes into contact with the earth before any of the vital organs of the vessel, such as the rudder and so forth, can be injured. The propellers also are

well out of danger, but a« any damage done to them mpy have serious consequences there is a special arrangement by which they may be turned by hand from their normal vertical position to a slanting position, parallel to the steel tubes of the outriggers that support them, which places them in complete safety. The car consists of a horizontal metal flooring. Beneath it are a rigid framework, which renders the car indeformable, and the two landing pivots. Above the flooring there is a rail 4ft high, closed in in the bow with aluminium plates and in the stern with metal gauze or grill. The interior is divided into compartments, all of which communicate from stem to stern. Successful First Flight. On September 14, after waiting in readiness in its shed for a full week owing to the violent north winds which have prevailed, the “Morning Post” National Fund Airship made its first flight with a success that more than satisfied even the high hopes of M. Julliot, its designer. For half an hour it manoeuvred over the plain of Moisson, obedient to the smallest movement of its helm. Its stability was perfect. . The airship neither rolled nor pitched in the slightest degree, as was clearly apparent to

those of us who watched the flight from below, an impression that was entirely confirmed hy every member of the crew, •nd the trial was the more striking and conclusive since the dirigible at 500 ft •bove the ground met with curious and difficult atmospheric conditions that neither the pilot nor anyone else had anticipated when it left the ground in a dead calm. Few, if any, airships, have been put to such a test at their first trial, and certainly none have ever come through such a test more triumphantly. Its success is the more remarkable since M. Scheffer had decided to run the motors at not more than half their power, in order to tune them up to their work gradually, although they had run at full speed in the shed for over an hour without giving the slightest cause for dissatisfaction. On this account the vessel was put to a very severe test, since speed is one of the most important factors in obtaining stability, and the helm has far less effect when the engines are running at a low speed.

AVIATION NERVE STRAIN. FLYING MEN RETIRE. M. Emile Dubonnet, the French airman, is about to give up flying. His> retirement supports the contention o. more than one medical authority, that the nerve strain of frequent flying is so great that it forces a man to abandon active airmanship in an extraordinarily short space of time. Many airmen admit that tins is so, and there is remarkable proof of it in the faet, that, although airmanship is in its infancy, the early pioneers are already vanishing and new champions taking Itheir place. The following pioneers have already retired from active flying in public:— M. Paulhan.—lntends to devote himself almost entirely to constructional work. M. Bleriot.—Has given up all except experimental flying with new machines of his own invention. Mr. Henry Furman.—Has abandoned flying, save for trials with newlydesigned machines. Wright Brothers.—Fly very rarely, being mostly concerned with constructional work. M. Rongier.—Retired after a bad fall in the sea at Nice. M. Fournier.’—Ceased to fly after a number of falls. M. Duray.—Forced to give up flying after being badly injured by a blow from his propellor. Mr. Moore-Brabazon.—Has relinquished flying at meetings. Mr. Cockburn.—Will do no more exhibition flying. Mr. Gibbs. —Compelled to retire temporarily as the result of a heavy fall at Wolverhampton. Captain Dickson.—Does not expect to fly at meetings after this season. Mr. Glen 11. Curtiss.-—Has very largely relinquished flying in favour of construction. M. Sommer.—Has become a constructor and rarely flies. Mr. Rawlinson.—Obliged to discontinue flying after his accident at Bournemouth. Mr. Mortimer Singer.—After a fall at Heliopolis last season has not flown again. "Mr. Grahame-White thus describes the nerve-strain of flying: "It is the tension of fearing that something unexpected may happen—that the engine may fail, that a stay may break, that a controlling wire may snap. Any one of these things may, one knows quite well, bring about a fearful fall. The rush of air, and the fact that one is high above the ground, has very little to do with the ordeal.” “Experience already proves,” was ‘the comment yesterday of an international authority, “that flying will become far more easy; aeroplanes are on the eve of enormous development so far as reliability is concerned.