Two pictures purporting to show the mysterious Chinese wing-in-ground-effect (WIG) craft – dubbed the “Bohai Monster” by some observers – emerged on social media last week, with one giving a full view of it above the water’s surface.
The other image shows the craft sitting on a pier, facing away from the camera. The vehicle has a boat-shaped fuselage with a horizontal stabiliser on top of the joined V-shape tail – a common configuration for WIG craft.
A buoyancy float can be seen fitted to each wingtip and four engines appear to be mounted side by side on top of the craft’s wings. The engines are widely considered to be jet-powered but military website The War Zone suggested they could be propeller engines.
A WIG craft – also known as an ekranoplan, as it is called in Russian – works on the “ground effect” principle, which describes an interaction between the underwing airflow and the surface below that produces a rise in static pressure and a reduction in drag.
The most famous WIG craft was a Soviet prototype developed in the 1960s – the “Caspian Sea Monster”, which was the biggest and heaviest aircraft in the world of its time. It was 92 metres (302 feet) long and had a maximum take-off weight of 544 tonnes.
By travelling over flat surfaces – ground or water – at low altitudes, WIG craft can take advantage of the reduced drag to travel more efficiently in terms of fuel and payload capacity than higher-flying aircraft.
