An Eisfeld-Valier-Rak-1 sledge test driven in February, 1929 on the Eibsee lake, Bavaria, Germany. Men fit rocket boosters in the unmanned sledge. The sledge stands in snow. Spectators watch nearby. A man lights a fuse and steps away. Rockets ignite and propel the sledge across the lake surface with considerable fire and smoke. The experimenters run to the sledge and extinguish smoking rockets by throwing snow on them.