aeronautics Aeronautics is the science or art involved with the study, design, and manufacturing of air flight–capable machines, and the techniques of operating aircraft and rockets within the atmosphere. The British Royal Aeronautical Society identifies ...

, spoilerons (also known as spoiler ailerons or roll spoilers) are spoilers that can be used asymmetrically as

flight control surfaces Aircraft flight control surfaces are aerodynamic devices allowing a pilot to adjust and control the aircraft's flight attitude. Development of an effective set of flight control surfaces was a critical advance in the development of aircraft. Ea ...

to provide roll control.

Operation

Spoilerons

roll Roll or Rolls may refer to: Movement about the longitudinal axis * Roll angle (or roll rotation), one of the 3 angular degrees of freedom of any stiff body (for example a vehicle), describing motion about the longitudinal axis ** Roll (aviation), ...

an aircraft by reducing the

lift Lift or LIFT may refer to: Physical devices * Elevator, or lift, a device used for raising and lowering people or goods ** Paternoster lift, a type of lift using a continuous chain of cars which do not stop ** Patient lift, or Hoyer lift, mobile ...

of the downward-going

wing A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expres ...

. Unlike ailerons, spoilers do not increase the lift of the upward-going wing. A raised spoileron also increases the drag on the wing where it is deployed, causing the aircraft to yaw. Spoilerons can be used to assist ailerons or to replace them entirely, as in the

B-52G The Boeing B-52 Stratofortress is an American long-range, subsonic aircraft, subsonic, jet-powered strategic bomber. The B-52 was designed and built by Boeing, which has continued to provide support and upgrades. It has been operated by the ...

which required an extra spoiler segment in place of ailerons present on other B-52 models.

Purpose

Spoilerons do not cause

adverse yaw Adverse yaw is the natural and undesirable tendency for an aircraft to yaw in the opposite direction of a roll. It is caused by the difference in lift and drag of each wing. The effect can be greatly minimized with ailerons deliberately designed to ...

, unlike ailerons. They are used in situations where

aileron An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement around ...

action would produce excessive wing twist on a very flexible wing or if wide-span flaps prevent adequate aileron roll control. They can also be used as spoilers. The

Mitsubishi MU-2 The Mitsubishi MU-2 is a Japanese high-wing, twin-engine turboprop aircraft with a pressurized cabin manufactured by Mitsubishi Heavy Industries. It made its maiden flight in September 1963 and was produced until 1986. It is one of postwar Japa ...

has double-slotted flaps that take-up the full length of the wing, to achieve good

STOL A short takeoff and landing (STOL) aircraft is a conventional fixed-wing aircraft that has short runway requirements for takeoff and landing. Many STOL-designed aircraft also feature various arrangements for use on airstrips with harsh conditio ...

performance. This leaves no room for ailerons, so it uses spoilerons instead. Spoilerons can be used during a stall, whereas ailerons must not be used in a stall because they will have the opposite to intended effect.

Disadvantages

Spoilerons reduce lift, increasing fuel usage. The lift reduction can be a problem in a one-engine inoperative situation.

Examples

An early use of spoilers augmenting small ailerons, known as ''guide ailerons'', was in the Northrop

P-61 Black Widow The Northrop P-61 Black Widow is a twin-engine United States Army Air Forces fighter aircraft of World War II. It was the first operational U.S. warplane designed as a night fighter, and the first aircraft designed specifically as a night fight ...

night fighter. The spoilers allowed wider-span flaps for a lower landing speed. The B-52 Stratofortress also had spoilers augmenting small ailerons, known as ''feeler ailerons''. These ailerons provided control forces to the pilot. The B-52G has no ailerons. The spoilers, situated inboard and forward of the trailing edge, are used for lateral control at high speeds to prevent excessive wing twist. The Mitsubishi Diamond Jet, Beechjet, and Hawker 400 family of business aircraft incorporate full length spoilerons that also double as speed spoilers during flight and landing. Another aircraft with full-length double-slotted flaps was the Wren 460. To go with large aileron deflections at low speeds it had a set of 5 feathering drag plates ahead of each aileron to overcome adverse aileron yaw and decrease lift on the low wing.

Boeing The Boeing Company () is an American multinational corporation that designs, manufactures, and sells airplanes, rotorcraft, rockets, satellites, telecommunications equipment, and missiles worldwide. The company also provides leasing and product ...

's line of jet airliners have flight spoilers which can act as roll spoilers. They are activated automatically when the control wheel is displaced more than 10 degrees. The

Tupolev Tu-154 The Tupolev Tu-154 (russian: Tyполев Ту-154; NATO reporting name: "Careless") is a three-engined, medium-range, narrow-body airliner designed in the mid-1960s and manufactured by Tupolev. A workhorse of Soviet and (subsequently) Russian ...

have fast-acting spoilers. They double as spoilerons that assist the ailerons when the pilot commands a high roll rate. These can be observed in operation when the pilot is fighting gusting crosswinds while landing.

Research

Several technology research and development efforts exist to integrate the functions of

aircraft flight control system A conventional Fixed-wing aircraft, fixed-wing aircraft flight control system consists of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's direction ...

s such as ailerons,

elevators An elevator or lift is a cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or decks of a building, vessel, or other structure. They are ...

elevon Elevons or tailerons are aircraft control surfaces that combine the functions of the elevator (used for pitch control) and the aileron (used for roll control), hence the name. They are frequently used on tailless aircraft such as flying wings. ...

flap Flap may refer to: Arts, entertainment, and media * ''Flap'' (film), a 1970 American film * Flap, a boss character in the arcade game ''Gaiapolis'' * Flap, a minor character in the film '' Little Nemo: Adventures in Slumberland'' Biology and he ...

flaperon A flaperon (a portmanteau of flap and aileron) on an aircraft's wing is a type of control surface that combines the functions of both flaps and ailerons. Some smaller kitplanes have flaperons for reasons of simplicity of manufacture, while s ...

s, and spoilerons into wings to perform the aerodynamic purpose with the goals of reducing mass, cost, drag,

inertia Inertia is the idea that an object will continue its current motion until some force causes its speed or direction to change. The term is properly understood as shorthand for "the principle of inertia" as described by Newton in his first law ...

(for faster, stronger control response), complexity (mechanically simpler, fewer moving parts or surfaces, less maintenance), and

radar cross section Radar cross-section (RCS), also called radar signature, is a measure of how detectable an object is by radar. A larger RCS indicates that an object is more easily detected. An object reflects a limited amount of radar energy back to the source. ...

for stealth. Expected applications include many

unmanned aerial vehicle An unmanned aerial vehicle (UAV), commonly known as a drone, is an aircraft without any human pilot, crew, or passengers on board. UAVs are a component of an unmanned aircraft system (UAS), which includes adding a ground-based controller ...

s (UAVs) and 6th generation

fighter aircraft Fighter aircraft are fixed-wing military aircraft designed primarily for air-to-air combat. In military conflict, the role of fighter aircraft is to establish air superiority of the battlespace. Domination of the airspace above a battlefield ...

. 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 The X-53 Active Aeroelastic Wing (AAW) development program is a completed American research project that was undertaken jointly by the Air Force Research Laboratory (AFRL), Boeing Phantom Works and NASA's Dryden Flight Research Center, where t ...

is a

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

effort. The

Adaptive Compliant Wing An adaptive compliant wing is a wing which is flexible enough for aspects of its shape to be changed in flight. Flexible wings have a number of benefits. Conventional flight control mechanisms operate using hinges, resulting in disruptions to the ...

is a military and commercial effort.

Fluidics

fluidics Fluidics, or fluidic logic, is the use of a fluid to perform analog signal, analog or Digital data, digital operations similar to those performed with electronics. The physical basis of fluidics is pneumatics and hydraulics, based on the theoret ...

, 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. In this use, fluidics promises lower mass, costs (up to 50% less), and very low

and response times, and simplicity.

References

{{Aircraft components Aircraft controls Aircraft wing design Aircraft wing components