ZMC-2 was the only successfully-operated metal-skinned airship ever built, and flew safely for over ten years. As a sub-scale test vehicle, it was considered to be very successful, but the company that built it did not weather the Great Depression well, and by the time a successor was planned, they had already scrapped it.
Zmc-2 1929

Schwarz's aluminum ship of 1897 and ZMC-2 were the only Metal-clad airships ever built due to high maintanance.