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Zeppelin LZ101 L55
Marine Luftschiff L55 Notlandung bei Tiefenort, Thuringen (location +- 2km 50°50’23”N 10°09’57”E )am 20 Oktober 1917.
First flight : 1 September 1917
Class : V
Two attacks dropping 5,450 kg (12,020 lb) of bombs. Heavily damaged in the second one on 19 October 1917, it drifted behind western front and rose to a Zeppelin all-time record altitude of 7,600 m (24,900 ft) to escape; then dismantled upon forced landing.
During the silent raid it dropped HE bombs causing little damage but at Bedwell Farm, south of Stevenage (location +- 1 km 51°54’12”N, 0°11’28”W ), three bombs demolished a farm building, injured a man, and damaged cottages. At Burleigh Farm, Langley, (location +-500m 51°52’42”N 0°13’46”W ) two HE bombs damaged buildings.
Participating in the 19/20 October 1917 silent raid, L55 broke the world altitude record for an airship. It went into an emergency climb to escape two French aircraft. With three engines out and the crew succumbing to altitude sickness, the ship could not be brought back under control until it had reached 24,600 feet. No other airship has since reached such a height. Although L55 wrecked while attempting to land in Germany, its unequaled climb was the only positive accomplishment in a night filled with disaster.
According calculations (see Zeppelin LZ94 ) a altitude of 7400 [m] is possible. At this height hydrogen had to be vented (automatical by emergency valves ?) otherwise the whole envelop would rip open by the inside overpressure of the hydrogen. However when descending the envelop had to be filled with outside air to keep pressure inside equal to outside but then de descent raid gets quickly to high and then a crash landing could not be avoided. Looking at above pictures it can be seen that the Zeppeling came to the ground with a high vertical speed crushing the structure on impact. Looks to me the crew would be wounded in the ruff landing…
The altitude at which an airship can fly largely depends on how much lifting gas it can lose due to expansion before stasis is reached. The ultimate altitude record for a rigid airship was set in 1917 by the L-55 under the command of Hans-Kurt Flemming when he forced the airship to 7,300 m (24,000 ft) attempting to cross France after the "Silent Raid" on London. The L-55 lost lift during the descent to lower altitudes over Germany and crashed due to loss of lift. While such waste of gas was necessary for the survival of airships in the later years of World War I, it was impractical for commercial operations, or operations of helium-filled military airships. The highest flight made by a hydrogen-filled passenger airship was 1,700 m (5,500 ft) on the Graf Zeppelin's around-the-world flight.
Literature :
Calculating Lifting Capacity of Airships | by Erik Engheim | Medium
The Airship Simon - Design (znuerb.com)
19/20 Oct 1917 (1) (iancastlezeppelin.co.uk)
https://luftschiff-46.de/Album/htm/zeigen_A-24.htm