(c) The suspension which binds the buoyant envelope to the car serves no other purpose. Note also the ingenious arrangement of two motors and two propellers, forming two independent systems, yet unitable under certain conditions. The placement of the propellers, rudders and stabilizing surfaces well above the bottom of the car, insures them against dangerous contact on landing, or while maneuvering near the ground.
The envelope is of rubberized Continental cloth. Its volume is 7,000 cubic meters, length 76.5 meters and major diameter 13.22 meters, or an elongation of 5.76 diameters. Inside the gas envelope is an air bag of 2,200 cubic meters. It is divided into two compartments, Q and Q´, which can be filled with air together or separately through the air duct, Q, joined to a blower, P, run by the two motors, or by hand when so desired. The balloon proper comprises two gas valves, R. Each compartment of the ballonet has one air valve, S. The valves of the type Clément-Bayard-Chauvière are automatic. Their construction is so perfect that for the first time in France, at least on a balloon of so large bulk, the blower runs continuously in constant communication with the ballonet, the pressure in the envelope remaining invariable, due to the regular play of the valves, which yield at the pressure for which they are set. They may also be Worked by hand from the pilot’s bridge in case of emergency. The envelope has on its upper side three ripping seams, one in the middle, the others toward either end. These rip panels can be worked together or separately, and permit the rapid deflation of the balloon.
The long car is attached to the hull by hempen duck feet fastened to a bolt rope running along the envelope below the equator; these duck feet terminate below in steel suspension cables fixed to the car. Below the principal bolt rope are others to which are fastened the duck feet of the oblique cords, which assure the perfect solidarity of the envelope and car. The steel cable sustainers have an ingenious patented regulating windlass. The girder car consists of a latticed girder, built of steel tubes united with cast-iron joints and steel-tie wires. Its whole length is 45 meters, of which 14.5 meters constitute the car proper. It is divided into segments which are easily demountable, thus rendering it easily transportable by truck or railway. The forward segment, A, tapers toward the front to a sharp point and is of triangular cross-section. The mid segment, B, constituting the car, has a quadrangular section of variable size. The rear segment, D, is of triangular section, diminishing progressively toward the rear, which rises to a sort of tail supporting the empennage and the direction rudders. The entire girder car when resting on the ground is supported by two pneumatic shock absorbers, U, U, projecting from its floor.
The car proper comprises three parts: in front, the motor and machine room, 2.5 meters wide; in the middle, the elevated bridge, N, for the pilot and his aide; in the rear, the passenger cabin, 8 meters long, 1.3 meters wide and 2 meters high for the observers and wireless telegraphy plant. The two reservoirs of essence, M, m, are placed above the passenger about the center of pressure. The blower P, for the ballonets, and the guide ropes T, are placed above the pilot’s bridge.
In the motor room are symmetrically arranged two Bayard-Clément engines, G G, separated enough to allow free passage between them. Each motor is elastically supported to obviate vibrations, and connects with the transmission shaft by a variable speed gear. The engines can be run separately or together by a connecting sprocket chain, and develop 100 to 130 horse-power each. The cooling of each motor is effected by an aluminum radiator, L L, of large surface.
The Chauvière propellers, K K, six feet in diameter, are driven by shafting and gear wheels at a normal speed of 250 rotations per minute. A special recording device serves to show their thrust at each instant, as also the torque of the motors.
The pilot, standing on the bridge where he enjoys a clear view, has immediate charge of the vessel’s movements. Before him are the various controls which he must operate, and the divers indicators which he must consult. These are the direction wheel, the manometers, the aneroid and registering barometers, the clinometer, the blower control to regulate the amount and distribution of pressure, the elevating-rudder wheel, the spark control, the ripping cord, the release string of the guide-rope, and the system of transmitting orders to the mechanicians whereby he can control the engines and the blowers which furnish air to the radiator and ballonet.
The direction and poise of the vessel in flight are controlled by the rudders and empennage at the rear, and its altitude from minute to minute is governed by the elevating biplane E´, of 30 square meters above the car in the mid region of the vessel.
The Patrie[81]
The Patrie, the third of its type, was first operated in 1906. The gas bag of the first balloon was built by Surcouf at Billancourt, Paris. The mechanical part was built at the Lebaudy Sugar Refinery. Since then the gas bags have been built at the Lebaudy balloon shed at Moisson, near Paris, under the direction of their aëronaut, Juchmes. The gas bag of the Patrie was 197 feet long with a maximum diameter of 33 feet, 9 inches, situated about 2/5 of the length from the front; volume 111,250 cubic feet; length approximately six diameters. This relation, together with the cigar shape, is in accordance with the plans of Colonel Renard’s dirigible, built and operated in France in 1884; the same general shape and proportions being found in the Ville de Paris.