Germany, Imperial, Weimar Republic. Three Zeppelin Commemorative Medals

1. LZ 4 was first flown on June 20, 1908, when a flight lasting eighteen minutes revealed the inadequacy of its steering arrangements. After modifications, further trials were made on June 23 and 29, and on July 1 a spectacular twelve hour cross-country flight was made during which it was flown over Switzerland to Zürich and then back to Lake Constance, covering 386 km (240 mi) and reaching an altitude of 795 m (2,600 ft). On July 13, 1908, the airship was reinflated with fresh hydrogen to ensure maximum lift for the planned 24-hour endurance trial, which was to be a return flight to Mainz. Shortly after setting off the next morning, a fan broke on the forward engine and it had to turn back. The following day it was damaged while being manoeuvered out of its hangar: repairs were not completed until the end of the month. The trial flight finally started on August 4th, when LZ 4 lifted off at 06:22 in the morning, carrying twelve people and sufficient fuel for thirty-one hours of flight. The flight to Zürich had excited considerable public interest, and large crowds gathered along the route to witness the flight, which took it over Konstanz, Schaffhausen, Basel and Strasbourg. Shortly after passing Strasbourg the forward engine had to be stopped since the fuel tank in the engine gondola had been exhausted, and needed to be refilled. At this point the airship was flying light due to the heat of the sun having caused the hydrogen to expand, and was being held at a low altitude by dynamic downforce generated by flying in a nose-down attitude: with the loss of the power of one engine, it rose to an altitude of 820 m (2,690 ft), venting gas from the relief valves as it did so. At 1:58 p.m the aft engine had to be stopped for refuelling: this time the airship rose to 884 m (2,900 ft), with a further loss of hydrogen. Two further engine stoppages caused further loss of gas: by now LZ 4 was only being kept in the air by dynamic lift generated by flying with a nose-up attitude, the resultant drag reducing its speed to 16 km/h (9.9 mph), and at 5:24 pm a landing was made on the Rhine near Oppenheim, 23 kilometres (14 mi) short of Mainz. All superfluous items and five crew members were unloaded, and the flight was resumed at 10:20. Mainz was reached half an hour later, and the ship turned to begin its return journey. Further engine problems followed: a crank bearing in the forward engine melted at 1:27 am, reducing airspeed to about 32 km/h (20 mph) and it was decided to land to have the engine repaired by engineers from the Daimler works at Untertürkheim. Accordingly, LZ 4 was set down at 7:51 am at Echterdingen. The airship was tethered and engineers removed the forward engine to make repairs, but during the afternoon LZ 4 was torn from its moorings by a gust of wind. The soldiers present as a ground handling party could not hold it down, but it was brought to earth by a crew member who had remained on board. Unfortunately, the ship came into contact with some trees while landing, which presumably damaged some of the gasbags, since it immediately caught fire. The cause of ignition was later ascribed to a static charge being produced when the rubberized cotton of the gasbags was torn. The disaster took place in front of an estimated 40 to 50 thousand spectators and produced an extraordinary wave of nationalistic support for Zeppelin's work. Unsolicited donations from the public poured in: enough had been received within 24 hours to rebuild the airship, and the eventual total was over six million marks were donated, at last providing Zeppelin with a sound financial base for his experiments.