Wing in Ground Effect

The Seaphantom: Wing In Ground Effect

Wing In Ground Effect

In fixed wing aircraft, ground effect is the increased lift and decreased drag that an aircraft wing generates when an aircraft is within one wingspan above the surface.

When landing, ground effect can give the pilot the feeling that the aircraft is “floating”. When taking off, ground effect permits an aircraft to become airborne at a speed less than the stall speed. The pilot can then fly level just above the runway while the aircraft accelerates in ground effect until a safe climb speed is reached.

Principle of ground effect

When an aircraft is flying at an altitude that is approximately at or below the same distance as the aircraft’s wingspan, there is, depending on airfoil and aircraft design, an often noticeable ground effect. This is caused primarily by the ground interrupting the wingtip vortices and downwash behind the wing. When a wing is flown very close to the ground, wingtip vortices are unable to form effectively due to the obstruction of the ground. The result is lower induced drag, which increases the speed and lift of the aircraft.

NASA Lifting Body

A lifting body is a fixed-wing aircraft configuration in which the body itself produces lift. In contrast to a flying wing, which is a wing with minimal or no conventional fuselage, a lifting body can be thought of as a fuselage with little or no conventional wing. Whereas a flying wing seeks to maximize cruise efficiency at subsonic speeds by eliminating non-lifting surfaces, lifting bodies generally minimize the drag and structure of a wing for subsonic, supersonic, and hypersonic flight, or, spacecraft re-entry. All of these flight regimes pose challenges for proper flight stability.

History

Lifting bodies were a major area of research in the 1960s and 70s as a means to build a small and lightweight manned spacecraft. The US built a number of famous lifting body rocket planes to test the concept, as well as several rocket-launched re-entry vehicles that were tested over the Pacific.

After the Challenger disaster in 1986, interest in employing the design as a Crew Recovery Vehicle and mini-shuttle to the Space Station began resulting in research at Langley Research Center. While the results proved the capability of the design, NASA did not pursue the concept any further. We, however, owe them our utmost gratitude for their assistance in the development of Seaphantom.