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Military


French Airships / Dirigeable - Before the Great War

The French [and German] military authorities began to consider airships as an arm of the Service in the closing years of the nineteenth century, and devoted both time and considerable sums of money in the attempt to bring them to perfection. Their appearance in the British Army was delayed for many years on account of the expense that would be incurred in carrying out experiments.

At the start of the Great War, France used a fleet of semi-rigid airships for offensive military purposes. However, they were vulnerable to airplane attack, and the French discarded them from their offensive arsenal. They did use nonrigid airships effectively for aerial observation, coastal patrol, convoying, and locating enemy submarines and mines. These airships could hover over a location and stay aloft for longer periods of time than conventional aircraft.

Classification, according to French authorities, from the military point of view, would seem to rest on volume as the determining factor.

  • Vedettes: 2000-4000 cubic meters and taking up three aeronauts. Limited radius of action; to accompany field armies and remain as close as possible to the enemy; easy to handle and to transport; rapidly inflated; no special hangars needed.
  • Scouts: 6000-7000 cubic meters. Capable of remaining up a considerable time and of going far; of special value when hostile armies are making their approach marches; special hangars needed.
  • Cruisers: "aerial dreadnoughts," exceeding 10,000 cubic meters; able to go far and remain up a long time, and thus available for strategic reconnaissance; to be concentrated near frontier and ready to start at the first signal; special hangars needed.
The Clement Bayard, and subsequently the Astra-Torres, non-rigids, followed on the early Lebaudys and carried French dirigible construction up to 1912. The Clement Bayard was a simple non-rigid having four lobes at the stern end to assist stability. These were found to retard the speed of the airship, which in the second and more successful construction was driven by a Clement Bayard motor of 100 horse-power at a speed of 30 miles an hour. On August 23rd, 1909, while being tried for acceptance by the military authorities, this vessel achieved a record by flying at a height of 5,000 feet for two hours. The Astra-Torres non-rigids were designed by a Spaniard, Senor Torres, and built by the Astra Company. The envelope was of trefoil shape, this being due to the interior rigging from the suspension band; the exterior appearance is that of two lobes side by side, overlaid by a third. The interior rigging, which was adopted with a view to decreasing air resistance, supports a low-hung car from the centre of the envelope; steering is accomplished by means of horizontal planes fixed on the envelope at the stern, and vertical planes depending beneath the envelope, also at the stern end.

One of the most successful of French pre-war dirigibles was a Clement Bayard built in 1912. In this twin propellers were placed at the front and horizontal and vertical rudders in a sort of box formation under the envelope at the stern. The envelope was stream-lined, while the car of the machine was placed well forward with horizontal controlling planes above it and immediately behind the propellers. This airship, which was named 'Dupuy de Lome,' may be ranked as about the most successful non-rigid dirigible constructed prior to the War.

The advanced type of dirigible, the Clement-Bayard II, of French design, was the most successful of the French military air fleet. In fact, the design of this airship incorporated all those features which the experience of aeronauts in other countries, notably Germany and Italy, has proved to be best adapted to aerial navigation, and it was said that future additions to the French aerial navy will be patterned after this type. Its predecessor, the Clement-Bayard I, made thirty voyages, some of them of considerable distances, without suffering any damage, but a study of its shortcomings led to their elimination in the following model.

The shape of the first Clement-Bayard has been retained, but it has been given more taper and more grace, the dimensions being 248.6 feet overall by 42.9 greatest diameter, this being but a short distance back of the bow. This gives it a ratio of length to diameter of 5.7. The gas balloonet stabilizers have been eliminated altogether. The total gas capacity is approximately 80,000 cubic feet. Like all French dirigibles it is of the true flexible type, the only rigid construction being that of the framework of the car itself.

The Clement-Bayard II made itself famous by its rapid and successful flight from the suburbs of Paris across the Channel to London, in October, 1910. This quick descent of one of the representatives of the French "fourth military arm" over the erstwhile sacred dividing line-the Channel-stirred the British mind, ever on the lookout for possibilities of foreign invasion, to an almost frenzied activity in aeronautical affairs. England at once entered the field and built one of the largest dirigibles ever constructed, "The Mayfly," a huge airship of the Zeppelin rigid type, which answered the query implied by its name, by not flying at all, as it was wrecked the first time an attempt was made to take it out of the shed.

After the disaster to La Republique in 1909, so little activity was shown in this field by France that the land which had given birth to the dirigible balloon seemed ready to discard what had been a source of considerable pride before it was equaled and then surpassed by Germany. From that time until the middle of 1911, only three very small units were added to the depleted French fleet, the Zodiac, Le Temps and Astratorres, and while these were very efficient for their size and were much used for training purposes, they made a sorry showing compared to what France had been doing previously.

A general reorganization was planned to build a new fleet of French military dirigibles capable of making altitudes of 6,000 to 7,000 feet, where they would be immune from any attack save that of aeroplanes which could be fought off. The scale on which this reorganization was planned is apparent in the amount of equipment used. To the only two airship sheds or "harbors" exceeding 400 feet in length previously to be found in the entire country, no less than nine were been added. All of these were 400 feet long and so built as to be readily enlarged to 600 feet. Each of these is designed to accommodate two of the big dirigibles at once. There were no less than six large hydrogen generating plants in France, one of them having a capacity of 360,000 cubic feet per day, and others of similar size are to be added.

The plans also included the building of a large fleet of big airships. The first squadron of the new fleet consisted of four vessels, the Lieutenant Selle de Beauchamp, Capitaine Marechal, Adjutant Vincenot, and the Adjutant Reau, all of them having been named after the officers who perished in the La Republique disaster. Their type is a clever development of the old Lebaudy and the Ville de Paris, of the classic La France type, the Adjutant Reau and its sister ship being patterned after the Ville de Paris, while the other two are improved Lebaudys. With about 250,000 cubic feet displacement, a length of 270 feet, beam 38 feet and a power-plant consisting of two 80-horse-power motors on each, these are the smallest of the four, but the most interesting, as the Lebaudy type with its single short car does not lend itself so readily to enlargement from the engineering point of view.

The total weight of the 1914 airship "Commandant Coutelle" with two pilots, two observers and four mechanics was said to be 2,200 kilograms. This dirigible airship has a gas volume of 9,500 cubic meters and a fabric surface of 3,250 square meters. It has two balloonets of 3,600 cubic meters and a total length of 92 meters, with a diameter of 14 meters. The envelope is made from double fabric caoutchoute with a wind resistance of 1,600 kilograms or 400 gramms per square meter. The framework of the car is 40 meters long and 2 meters high with a width of 1.3 meters. It was located at a distance of 5 meters below the balloon. The total height of the airship including the balloon and car was 21 meters. The balloon proved very successful in many flights.





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Page last modified: 07-07-2012 19:26:35 ZULU