The volume of this airship is 26,000 cubic metres (918,000 cubic feet). It will be seen, therefore, that this mammoth airship in size surpasses even the largest Zeppelins.
II. Semi-rigid.
(i.) Lebaudy (French).—This airship is a crossbreed between the rigid and non-rigid systems. By this method of construction a considerable amount of support can be imparted to the gas-bag, though it does not dispense with the services of the ballonet, as does the entirely rigid type. To the genius of M. Julliot, Messrs. Lebaudy Brothers’ engineer, we are indebted for the introduction of this excellent type. It no doubt forms an exceedingly serviceable military airship. In the Lebaudy original airship the underside of the balloon consisted of a flat, rigid, oval floor made of steel tubes; to these the stability planes were attached, and the car with its engine and propellers was suspended. This secured a more even distribution of weight over the balloon. The gas-bag was dissymmetrical in form. Though not exactly resembling that excellent pattern, “La France,” it partook of the important quality of having the master diameter near the front. The car was a steel frame, covered with canvas, and in the form of a boat. The screw propellers were placed on either side of the car.
In 1909, as the British Government at that time possessed only very small airships, the nation raised a sum of money by subscription to present the Government with one of efficient size. The military authorities compiled a list of somewhat severe tests which, in their opinion, they thought an airship should be able to perform before acceptance. At the request of the Advisory Committee, of which Lord Roberts was chairman, the writer went to France in an honorary capacity to select the type of airship to be adopted. There was at that time only one firm of airship makers in France who were willing to undertake the formidable task of making an airship that would come up to the requirements of the British Government—the brothers Lebaudy, whose engineer and airship designer was M. Julliot.
The semi-rigid airship which M. Julliot designed and executed was without doubt a chef d’œuvre of its kind. The rigid tests it had to undergo necessitated a modification of some of the details that were conspicuous in the airships the constructor had previously built.
In this airship the girder-built underframe was not directly attached to the balloon, but suspended a little way beneath it.
The gas envelope had a cubic capacity of 353,165.8 cubic feet; the length was 337¾ feet. There were two Panhard-Levasseur motors of 135 h.p. each.
On October 26th, 1910, this airship made an historic and record flight over the Channel from Moisson to Aldershot in five hours twenty-eight minutes, at a speed of some thirty-eight miles an hour, sometimes against a wind of twenty-five miles an hour. Unfortunately, owing to a miscalculation by those responsible, the shed which had to receive the new airship on its arrival was made too small to house it safely. While the airship was being brought into the shed its envelope was torn and placed hors de combat.
Since this airship was made the Lebaudy brothers have ventured to still further increase the size of their semi-rigid airships.
(ii.) Gross (German).—This airship may be described as being more or less a German reproduction of the Lebaudy type. It forms part of the German airfleet. A considerable number have been made of various sizes (for dimensions, etc., see table, German Airships, Chapter IV., [page 38]).