User:TheLongTone/LZ 18 (L 2)

LZ 18 (Navy designation (L 2) was the second Zeppelin airship to be bought by the Kriegsmarine. It caught fire and crashed with the loss of all aboard on 18 October 1913.
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Design
On January 18 1913 Admiral Alfred von Tirpitz, Secretary of State of the German Imperial Naval Office, obtained the agreement of Kaiser Wilhelm II to a five-year program of expansion of the German naval airship strength. A contract was placed for the first ship on 30 January, one requirement being that the craft should be capable of bombing England. The design was heavily influenced by the [naval architect Felix Pietzker, who was an advisor to the German Admiralty Aviation Department. Construction started in May. The length and overall height of the ship were limited by the size of the Navy's airship shed at Fuhlsbüttel, but but Pietzker's proposals enabled the diameter of the airship to be increased without increasing  overall height by changing the position of the keel, changing it from a structue below the main hull structure to within it, and secondly by placing the engine cars closer to the hull. It was powered by four 165 hp Maybach engines in two engine cars, each car driving via driveshafts and [[bevel gears a pair of four-bladed propellers mounted either side of the envelope. The ship was controlled from a third gondola mounted in front of the forward engine car.

Operational history
LZ 18 was first flown on 6 September at Freidrichhafen, and following a number of trial flights was flown to Johannisthal on 20 September for naval acceptance trial to begin, the flight of about 700 km (438&nbspmi) taking twelve hours. The ship's tenth flight was to be an altitude trial and was scheduled for 17 October. The airship was removed from its shed in the morning but takeoff was delayed because one of the engines would not start. The delay of two hours while the engine was repaired allowed the morning sun to heat the hydrogen, causing it to expand. This caused the airship to ascend rapidly to 2000 ft, when horrified observers on the ground saw a flame leap out of the forward engine car, causing the explosion of some of the gasbags. Halfway to the ground there was a second explosion, and as the wreckage hit the ground furter explosions followed as the fuel tanks detonated. Three survivors were pulled from the blazing wreckage, but two died shortly afterwards and the third died that night in hospital. In all 28 men died, including Pietzker, and the chief of the Admiralty Aviation Department, Korvettenkapitän Behnisch. The accident was agreed to have been caused by the rapid ascent leading to venting of hydrogen through the relief valves, which in Zeppelins of the period were placed at the bottom of the bags, without vent trunks to convey any hydrogen let off to the top of the ship. Some of the vented gas was sucked into the forward engine car, where it was ignited.