COMMENT
WE’RE USED TO FOILING BOATS – BUT WHAT ABOUT CRAFT THAT FLY JUST ABOVE THE WATER? IT SEEMS ‘GROUND EFFECT’ VESSELS ARE MAKING A COMEBACK
The Caspian Sea Monster was every bit as intimidating as its name suggests. At over 100ft long it flew at 230 knots just 20ft above the water’s surface. With a lift capacity of 550 tonnes and 10 jet engines spread along its stubby wings and tail fin it was a beast of a machine.
Known officially as the Korabl Maket (KM) it was the largest in a line of ground effect aircraft designed and built in the Soviet Union from the late 1950s through to the mid-1980s as part of the Ekranoplan project.
Despite having unusually short wings the KM could cover long distances at high speed as well as being able to carry much higher payloads more efficiently than a conventional aircraft of a similar size. In theory it was a winner, but in practice there were problems.
Maintaining stable flight close to the surface was said to be challenging for the pilots and when the sea state built it became difficult, if not impossible, to operate.
Manoeuvring was also an issue and required plenty of advanced warning to avoid obstacles. And then there was the issue of getting airborne in the first place. While the Sea Monster was efficient in flight it took a huge amount of power to get there. So, by the end of the 1980s as the Cold War started to thaw, the Ekranoplan project had pretty much fizzled out for the big beasts. But development in smaller ground effect vessels continued.
Back in the 1990s I was involved with Top Gear for a BBC series called Waterworld. One of the stories we ran was about a new ground effect craft that looked like a small private plane with stubby wings. It was a fascinating project but since then I’d heard nothing more, until now.
One of the latest projects for composite experts Moore Brothers in Bristol, Rhode Island, USA, has taken them in a new direction with the construction of a remote-controlled prototype for a company called Regent (Regional Electric Ground Effect Nautical Transportation) that is building what it calls seagliders.
The prototype quarter scale model is a test platform with an 18ft wingspan that uses similar aspects to the Ekranoplan project, but with an interesting twist.
Aside from being fully electric, Regent’s seaglider uses retractable foils to lift itself clear of the water with the minimum of fuss. Like any hydrofoil vessel, once the hull is above the surface the seaglider is operating at much lower drag and can reach the required speed where ground effect comes into play more quickly.
From there, airspeed builds and the wings take over.
The model is one of the early steps towards full size versions which include one with a 65ft wingspan and capacity for 12 passengers and two crew, and a
