Owing to the ever-increasing defensive measures of the enemy the airships at the front were built in two sizes, the types being "L50" and "L 70.
The chief distinctive features of the former [L50] were five motors, each of 260 h.p., and such as could develop sufficient speed even in the highly rarefied atmosphere of the upper strata of the air ; four propellers, all coupled directly to the shafts (the two rear motors are coupled to one propeller); a central gangway, 196.5 m. long; a breadth of 23.9 m. ; a gas capacity of 55,000 cb.m. ; a speed of 30 metres per second (about 110 km. per hour); a load of 38 tons.
Type "L 70 " : Seven motors, each of 260 h.p.; six propellers; central gangway, 21 1.5 m. ; greatest diameter, 23.9 m. ; volume of gas, 62,000 cb.m.; speed, 35 metres per second (equal to 130 km. per hour) ; load, 43 tons.
The "L50 " carried a crew of 21, and "L 70" one of 25, among whom were 1 Commander, 1 Officer of the Watch, 1 Quarter-Master, 1 Chief Artificer-Engineer, 2 men for lifting gear (Yeomen of Signals,) 2 men for the balancing gear (Boatswains), 2 Motormen (stoker petty officers) for each motor, 1 Sailmaker, 1 Petty Officer Telegraphist, and 1 Ordinary Telegraphist for the wireless installation.
They carried two machine-guns, and later on a 2-cm. gun as well. The supply of bombs consisted of incendiary bombs of 11.4 kilo weight, and explosive bombs of 50, 100, and 300 kilos.
