The material for the gas bag of the new air ship was furnished by the Continental Tire Company. It is made up as follows:
| Weight oz. per square yard. | |
|---|---|
| Outer yellow cotton layer | 3.25 |
| Layer of vulcanized rubber | 3.25 |
| Layer of cotton cloth | 3.25 |
| Inner layer of rubber | 0.73 |
| ——— | |
| Total weight | 10.48 |
It is interesting to note the changes which this type has undergone since the first one was built. The Jaune, constructed in 1902–3, was pointed at the rear and had no stability plane there; later it was rounded off at the rear and a fixed horizontal plane attached. Finally a fixed vertical plane was added. The gas bag has been increased in capacity from 80,670 cubic feet to about 131,000 cubic feet. The manufacturers have been able to increase the strength of the material of which the gas bag is made, without materially increasing the weight. The rudder has been altered somewhat in form. It was first pivoted on its front edge, but later on a vertical axis, somewhat to the rear of this edge. With the increase in size, has come an increase in carrying capacity and, consequently, a greater speed and more widely extended field of action.
Ville de Paris
This air ship was constructed for Mr. Deutsch de la Meurthe, of Paris, who has done a great deal to encourage aërial navigation. The first Ville de Paris was built in 1902, on plans drawn by Tatin, a French aëronautical engineer. It was not a success. Its successor was built in 1906, on plans of Surcouf, an aëronautical engineer and balloon builder. The gas bag was built at his works in Billancourt, the mechanical part at the Voisin shop, also in Billancourt. The plans are based on those of Colonel Renard’s air ship, the France, built in 1884, and the Ville de Paris resembles the older air ship in many particulars. In September, 1907, Mr. Deutsch offered the use of his air ship to the French Government. The offer was accepted, but delivery was not to be made except in case of war or emergency. When the Patrie was lost in November, 1907, the military authorities immediately took over the Deutsch air ship.
Gas Bag.—The gas bag is 200 feet long for a maximum diameter of 34½ feet, giving a length of about 6 diameters, as in the France and the Patrie. Volume, 112,847 cubic feet; maximum diameter at about ⅜ of the distance from the front, approximately, as in the Patrie. The middle section is cylindrical with conical sections in front and rear. At the extreme rear is a cylindrical section with eight smaller cylinders attached to it. The ballonet has a volume of 21,192 cubic feet or about ⅕ of the volume, the same proportion found in the Patrie. The ballonet is divided into three compartments from front to rear. The division walls are of permeable cloth, and are not fastened to the bottom so that when the middle compartment fills with air, and the ballonet rises, the division walls are lifted up from the bottom of the gas bag, and there is free communication between the three compartments. The gas bag is made up of a series of strips of perpendicular to a meridian line. These strips run around the bag, their ends meeting on the under meridian. This is known as the “barchistode” method of cutting out the material, and has the advantage of bringing the seams parallel to the line of greatest tension. They are therefore more likely to remain tight and not allow the escape of gas. The disadvantage lies in the fact that there is a loss of 33⅓ per cent of material in cutting. The material was furnished by the Continental Tire Company, and has approximately the same tensile strength and weight as that used in the Patrie. It differs from the other in one important feature—it is diagonal thread, that is, the warp of the outer layer of cotton cloth makes an angle of 45 degrees with the warp of the inner layer of cotton cloth. The result is to localize a rip or tear in the material. A tear in the straight thread material will continue along the warp, or the weave, until it reaches a seam.
Valves.—There are five in all, made of steel, about fourteen inches in diameter; one on the top connected to the car by a cord, operated by hand only; two near the rear underneath. These are automatic but can be operated by hand from the car. Two ballonet valves directly under the middle are automatic and are also operated from the car by hand. The ballonet valves open automatically at a pressure of 2/3 inches of water; the gas valves open at a higher pressure.
Suspension.—This air ship has the “long” suspension. That is, the weight is distributed along practically the entire length of the gas bag. A doubled band of heavy canvas is sewn with six rows of stitches along the side of the gas bag. Hemp ropes running into steel cables transmit most of the weight of the car to these two canvas bands and thus to the gas bag. On both sides and below these first bands are two more. Lines run from these to points half way between the gas bag and the car, then radiate from these points to different points of attachment on the car. This gives the triangular or nondeformable system of suspension, which is necessary in order to have the car and gas bag rigidly attached to each other. With this “long” suspension, the Ville de Paris does not have the deformation so noticeable in the gas bag of the Patrie.
The Car.—This is in the form of a trestle. It is built of wood with aluminum joints and O.12 inch wire tension members. It is 115 feet long, nearly 7 feet high at the middle and a little over 5½ feet wide at the middle. It weighs 660 pounds and is considered unnecessarily large and heavy. The engine and engineer are well to the front, the aëronaut with steering wheels is about at the center of gravity.
Motor.—The motor is a 70 to 75-horse-power Argus, and is exceptionally heavy.