159,079. Finley, T. M. Dec. 24, 1919. Airships; aerostats; cars and cabins; framework; propelling; steering, balancing, and regulating altitude; tanks and like containers, arrangement and disposition of.-A rigid airship of crescent-shaped cross - section has a lower longitudinal air passage with geared ends, a top longitudinal girder carrying main transverse frames, means for heating the space between the gas-bags and outer cover, a control cabin on the top, a number of lifting-screws, means for compressing hydrogen withdrawn from the main part of each gas-bag into bottom sections, ballonets for air, and propellers in the air passage. A compound truss 1, Figs. 4 and 8, running along the top of the ship is formed of two parallel units with upper and lower booms 2, 3, 8, 9 connected by vertical struts and inclined stays and also transversely by struts 6, 7. At the main transverse frame positions vertical struts 10, Fig. 9, depend from the truss to centre pieces 44. The transverse framework comprises tubes 41, 42, radiating from the centre piece to the outer tubes 21, 20 and passage tubes 22, vertical tubes as 72, horiontal tubes as 70, and stay wires. The main frames are joined by straight main longitudinals and the whole hull provided with a cover. At the bow and stern the passage formed by the tubes 22 flares out to form two pointed prows at each end. For propelling, a number of screws 132, 133 are carried in the passage way by framework depending from the main truss, and screws are also mounted on the cabins 87 which are carried by a lower girder work 60 suitably braced and stayed to the main transverse frames. The engines are located in a cylindrical casing with hemispherical tank forming a tail, and the propeller boss has a similar hemispherical casing. The radiator is adapted to be raised from and lowered into a casing for controlling the degree of cooling. The fuel is supplied to the tail tanks from main tanks in the bottom of the car. The engines on the cars are mounted so as to be adjustable in height and capable of complete detachment. For steering and manoeuvring, tail vertical rudders 134 and horizontal rudders 148 are provided; also main truss cylinders 117 may be formed in which electrically actuated lifting screws 118 are placed, a cover 120 operated from the control cabin closing the cylinder when the screws are inoperative. In addition, each gas-bas has diaphragms 110, 112, the space 111 between which forms an air ballonet and the space 113 beneath the lower one forming a bag for the reception of compressed hydrogen which is drawn from the main portionof the bag. Bellows pumps 114 are operated from the gangway to compress air or withdraw it from the ballonets, and also to effect an interchange of hydrogen as between the storage chamber 113 and the gas-bag proper. This arrangement avoids the necessity for using ballast. Additional control is effected by supplying hot air to the space between the outer cover and gas bags. For this purpose, the exhaust silencers are provided with tubes through which air is drawn and heated and thence supplied to the lower longitudinals 78, which are pierced at each main gas bag section. The tubes connecting the longitudinals with the silencer are enclosed in a second tube with a vacuous space between. The outer cover has a number of cowls for carrying off the air after it has taken up any gas leakage from the bags.