Spoileron

In aeronautics spoilerons are flight control surfaces, specifically spoilers that can be used asymmetrically to achieve the effect of ailerons.

Operation

Spoilerons help to roll an aircraft by reducing the lift of one wing, but, unlike ailerons, not by increasing the lift of the other wing. As a side effect, a raised spoileron also increases the drag on one wing which causes the aircraft to yaw, which can be compensated with the rudder. Since roll and yaw motion are, however, both to the wing with the raised spoileron, it is usually desirable. Spoilerons can be used to assist the ailerons or replace them entirely, thereby reducing the number of required control surfaces.

Usage

An early use of spoilerons was in the Northrop P-61 Black Widow night fighter.

The B-52 Stratofortress has no ailerons as they would cause excessive twisting of the highly flexible wing. It achieves roll control entirely through spoilerons mounted near the center of the wing in about the same place as most gliders.

The Mitsubishi Mu-2 has double-slotted flaps that take-up the full length of the wing, leaving no room for ailerons. Like the B-52 it has spoilerons near the center of the wing.

Another aircraft with full-length double-slotted flaps was the Wren 460. It had a series of spoilerons on each wing that twisted broadside to the wind to assist with roll control.

Boeing's line of jet airliners have fast-acting spoilers. They double as spoilerons that assist the ailerons when the pilot commands a high roll rate. These can be readily seen in operation when the pilot is fighting gusting crosswinds when landing.

Research

Several technology research and development efforts exist to integrate the functions of aircraft flight control systems such as ailerons, elevators, elevons, flaps, flaperons, and spoilerons into wings to perform the aerodynamic purpose with the goals of reducing mass, cost, drag, inertia (for faster, stronger control response), complexity (mechanically simpler, fewer moving parts or surfaces, less maintenance), and radar cross section for stealth. Expected applications include many unmanned aerial vehicles (UAVs) and 6th generation fighter aircraft. Two promising approaches are: flexible wings; and fluidics.

Flexible wings

In flexible wings, much or all of a wing surface can change shape in flight to deflect air flow. The X-53 Active Aeroelastic Wing is a NASA effort. The Adaptive Compliant Wing is a military and commercial effort.^[1][2][3]

Fluidics

In fluidics, forces in vehicles occur via circulation control, in which larger more complex mechanical parts are replaced by smaller simpler fluidic systems (slots which emit air flows) where larger forces in fluids are diverted by smaller jets or flows of fluid intermittently, to change the direction of vehicles.^[4][5][6] In this use, fluidics promises lower mass, costs (up to 50% less), and very low inertia and response times, and simplicity.

See also

• Flight control surfaces
• Flaperon
• Elevon

References

1. Scott, William B. (27 November 2006), "Morphing Wings", Aviation Week & Space Technology
2. "FlexSys Inc.: Aerospace". Retrieved 2011-04-26.
3. Kota, Sridhar; Osborn, Russell; Ervin, Gregory; Maric, Dragan; Flick, Peter; Paul, Donald. "Mission Adaptive Compliant Wing – Design, Fabrication and Flight Test" (PDF). Ann Arbor, MI; Dayton, OH, U.S.A.: FlexSys Inc., Air Force Research Laboratory. Retrieved 2011-04-26.
4. P John (2010). "The flapless air vehicle integrated industrial research (FLAVIIR) programme in aeronautical engineering". Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering (London: Mechanical Engineering Publications) 224 (4): 355–363. doi:10.1243/09544100JAERO580. ISSN 0954-4100.
5. "Showcase UAV Demonstrates Flapless Flight". BAE Systems. 2010. Retrieved 2010-12-22.
6. "Demon UAV jets into history by flying without flaps". Metro.co.uk (London: Associated Newspapers Limited). 28 September 2010.