Maanpaikan

Maanpaikan is a Finnish term that roughly translates to "ground effect" or "ground cushion." It refers to a phenomenon observed in certain types of aircraft, most notably ground effect vehicles (GEVs) and some ekranoplans, where the air trapped between the vehicle's wings and the ground creates a cushion of high pressure. This increased pressure under the wings reduces the induced drag experienced by the aircraft, allowing it to fly with less power and at lower altitudes.

The effect becomes more pronounced as the vehicle approaches the surface of the ground or water. The wings are designed with a specific shape, often with a downward-curving trailing edge or a large span relative to their chord, to optimize the trapping of air. This allows these vehicles to achieve efficient flight at very low altitudes, typically just a few meters above the surface.

Maanpaikan is the principle behind the operation of GEVs, which are designed to fly over water or flat land. These vehicles are not considered aircraft in the traditional sense because they operate at altitudes too low to achieve full aerodynamic lift from the ground effect alone. They are also not boats, as they are designed to lift off the surface and fly. The efficiency gained from the ground effect means that GEVs can be faster than conventional boats while consuming less fuel.

The development and application of maanpaikan technology have been primarily explored by Russia, with its ekranoplans being prominent examples. These large craft were designed for military purposes, such as troop transport and anti-submarine warfare, leveraging the speed and stealth afforded by low-altitude flight over water.