Photographs of an immense Soviet craft skimming the Caspian Sea once puzzled observers. It looked partly like a plane, partly like a ship, and completely unlike the machines most people knew.
Known in the West as the “Caspian Sea Monster”, the experimental KM ekranoplan was an example of ground-effect flight. A wing moving close to a surface can benefit from altered airflow and reduced induced drag; engineers hoped to exploit that effect for large vehicles travelling low over water.
Flying, but barely above the waves.
Designer Rostislav Alekseyev's machine flew in the 1960s. The broader Soviet programme explored the military potential of ekranoplans, including later craft such as the missile-carrying Lun.
There was a trade-off. Remaining close to the sea could offer useful aerodynamic performance, but enormous size, demanding take-offs and practical operating constraints made these machines difficult propositions.
The Caspian Sea Monster survives as a wonderful lesson in engineering ambition: some of the strangest-looking vehicles were built for very serious reasons, even if they never became everyday transport.
Our editorial graphics are stylised artwork, not documentary photographs or historical reconstructions.
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