Aircraft/Components

There are thousands of designs and ideas about aircraft which have been developed through aviation history. Despite this some main components became permanent in every aircraft design. As fix-wing aircrafts are the most common aircrafts they will be the most studied.

Fixed-wing aircraft components

Although airplanes are designed for a variety of purposes, most of them have the same major components. The overall characteristics are largely determined by the original design objectives. Most airplane structures include a fuselage, wings, an empennage, landing gear, and a powerplant. There are many other parts as well.

Fuselage

The fuselage includes the cabin and/or cockpit, which contains seats for the occupants and the controls for the airplane. In addition, the fuselage may also provide room for cargo and attachment points for the other major airplane components. Some aircraft utilize an open truss structure. The truss-type fuselage is constructed of steel or aluminum tubing. Strength and rigidity is achieved by welding the tubing together into a series of triangular shapes, called trusses.

Empennage

The empennage (also called tail) is the rear part of the aircraft. Usually it includes the stabilizers, rudder and elevator as many other components. In fighter jets it may be constructed around the exhaust nozzle, as in some three-engine airplanes ( with the third engine in the fuselage). In commercial air crafts, the empennage is built from the cabin pressure-cone and may contain the Flight Data Recorder ("black box"), Cockpit Voice Recorder that can help tell what happened in a crash also need it there is a pressure out-flow valve.

Wings

The wings are airfoils attached to each side of the fuselage and are the main lifting surfaces that support the airplane in flight. There are numerous wing designs, sizes, and shapes used by the various manufacturers. Each fulfills a certain need with respect to the expected performance for the particular airplane. Wings may be attached at the top, middle, or lower portion of the fuselage. These designs are referred to as high-, mid-, and low-wing, respectively. The number of wings can also vary. Airplanes with a single set of wings are referred to as monoplanes, while those with two sets are called biplanes. Many high-wing airplanes have external braces, or wing struts, which transmit the flight and landing loads through the struts to the main fuselage structure. Since the wing struts are usually attached approximately halfway out on the wing, this type of wing structure is called semi-cantilever. A few high-wing and most low-wing airplanes have a full cantilever wing designed to carry the loads without external struts.

Control surfaces

Airplane control.jpeg

As aircraft move in three dimensions, we need various control devices to control it. Fix-wing aircraft have control surfaces for each one of these dimensions. Usually, these are placed in the extremes of the aircraft (tail and wings) to get the maximum strength and response using small moving parts thanks to the lever concept.

Note that an airplane is easier to maneuver the more unstable it is. Stability can be provided by stabilizers and fuselage and wing design.

Vertical stabilizer and rudder

The vertical stabilizer functions with the same principle a wing does but being symmetrical. It is the main control surface of airplanes (fix-wing aircraft). Obviously, it has a vertical position, usually in the tail of the aircraft. There can be multiple vertical stabilizers (in large aircraft usually).

The vertical stabilizer has a moving part which is called Rudder. This acts as an aileron does in the wing. When it is moved to one or other side it produces a pressure difference over to the stabilizer since it's movement is equal to change the angle of attack of this 'wing'.

The rudder controls the Y-axis or Yaw of the plane and it is controlled from the cockpit with the pedals. In a coordinated turn, rudder and ailerons must be coordinated, but you can use rudder only to 'slide' the aircraft.

Some rudders are mixed with elevators in the same control surface, creating V-tail aircraft.

Rudder

Horizontal stabilizer and elevator

The horizontal stabilizer is the main control surface of the aircraft, mainly of airplanes (fixed-wing aircraft). It functions as a wing does, creating a second point of lift along the fuselage which provides stability to the aircraft in the Z-axis. Its function is not to provide more lift but to control the Pitch of the aircraft (by modifying the angle of attack of the wing). This is thanks to a moving part or parts called Elevators, which act like an aileron, and are controlled by the longitudinal axis of the joystick or wheel.

Obviously, the horizontal stabilizer has a horizontal position, usually in the tail of the aircraft. It can be on top of the vertical stabilizer (T-tail aircraft) or divided into two parts crossing the vertical stabilizer. Some horizontal stabilizers have no elevators but are a whole elevator (mainly in gliders, since it has better aerodynamic performance). In Canard-configuration planes, the vertical stabilizer is positioned not in the tail but in the nose of the aircraft (note that its movement to reduce or increase pitch will be inverted from the one it does when it's placed in the tail).

Sometimes, elevators are mixed with rudders in the same control surface, creating V-tail aircraft. It also can be combined with ailerons, mainly in delta-wing planes.

Elevator

Aileron

Ailerons are moving surfaces usually placed near the tips of the wings. The function of aileron is simple, by moving upwards or downwards it modifies the angle of attack of that section of the wing, sinking or lifting it. This change in the aerodynamic is due to the modification of the relative curve of the airfoil. Note that ailerons are complementary, so if one moves the other will move on the other direction in the same proportion. This improves the effect as one wing is lifted and the other sunk. Ailerons control the X-axis or roll movement of the aircraft.

Ailerons are controlled by the pilot from the cockpit, with the lateral axis of the joystick. To make coordinated turns the movement must be combined with the rudder in the same direction. In some planes ailerons are just divided elevators, being possible to use the same surface as aileron or elevator (delta-wing airplanes).

Aileron

Trim tab

Trim

Lift control devices

As well as speed and pitch (angle of attack), there are some devices which make possible to modify the lift produced by the wing. These act on the aerodynamics of the wing, mainly on the boundary layer.

Flap

Flaps increase the wing surface or curve generating more lift with the same speed. They are commonly used on low speed operations, mainly during landings and take offs.

There are several types of flaps:

Plain Flap
Split Flap
Flap Zap or Slotted
Flap Fowler
Flap Multi-Fowler

Flap

Slat

A slat is a thin airfoil deployed from the leading edge of the wing. This acts as a new little wing, but its objective is not to produce lift but to generate the circulation needed for it. Slat circulation will be opposite to wing circulation reducing the highest speed of the boundary layer. This reduces the maximum lift also, making its distribution along the wing softer, but allowing the boundary layer to detach later (by reducing the adverse pressure generated in the trailing edge).

Usually, slats are used with flaps during take off and landing operations as both produce extra lift at low speed.

http://en.wikiversity.org/wiki/Leading-edge-device

Spoiler

Spoilers are not used for generating lift but for reducing it. They are moving surfaces which are placed vertically across the airfoil. This produces the detachment of the boundary layer earlier than usual as an adverse pressure is generated.

These devices are not very common in piston engine or turboprop airplanes but in turbojet airplanes and gliders.

Spoilers are used mainly after touch down (landing) and rarely used during the decend and approach.Speedbird 19:20, 1 April 2007 (UTC)Saif Arafa

Powerplant and propulsion devices

Propeller

A propeller is a device which transmits power by converting it into thrust for propulsion of a vehicle such as an airplane, ship, or submarine though a fluid such as water or air, by rotating two or more twisted blades about a central shaft, in a manner analogous to rotating a screw through a solid. The blades of a propeller act as rotating wings, and produce force through application of both Bernoulli's principle and Newton's third law, generating a difference in pressure between the forward and rear surfaces of the airfoil-shaped blades.

Piston engine

Piston engines are common four-stroke cycle engines. They are designed in particular for airplanes, so they use aviation gas and have special characteristics, but their function is very similar to a car engine. Transmission of these engines is connected to a propeller so they can provide thrust. Full details in this page end to see more option in their websites.

Jet engine

A jet engine produces thrust by compressing air and releasing it through a directed pipe or nozzle. We will study more deeply this subject in Chapter 3, but essentially an aircraft jet engine is composed of an intake chamber or valve, a fan, one or several compressors, a combustion chamber, one or several turbines and an exhaust nozzle.

The process the air suffers through a jet engine begins with the intake and initial compression, a much higher compression, combustion, discharge into turbines and release. It is common to see jet engines with one more step which is to afterburn the mixture while being released.

TurboJet
TurboFan

TurboProp

A TurboProp engine consists in a jet engine which drives a propeller. The result of this is that we have a much more reliable engine than a piston engine (as much as a jet engine) but not as complicated and big as a jet engine since we don't need the jet-blast for generating thrust but the propeller.

Landing gear

Nose gear

also used for turns during taxing and

Main gear

Cockpit

A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a pilot controls the aircraft. Most modern cockpits are enclosed, except on some small aircraft.

Controls

Information devices

Navigation devices

Radio
INS
RNAV/GNSS

FMS

Flight Management System.

Communication devices

A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a pilot controls the aircraft. Most modern cockpits are enclosed, except on some small aircraft.

Systems

Hydraulic

Hydraulic systems are used to move and actuate landing gear, flaps, and brakes. Larger aircraft's use these systems also on flight controls, spoilers, thrust reversers and what not.

The reason to use hydraulics is because they are able to transmit a very high pressure or force with a small volume of fluid (hydraulic oil). power assisted brakes is one application where you will see hydraulics the most in small experimental, isa and ultralight aircrafts.

Electric

Pneumatic (Bleed)

APU

The APU is a small jet engine that is used to start the larger jet engines. In airliners it's usually at the very rear of the aircraft, below the tail. Large engines are heavy and require a lot of torque to spin up, more than a starter battery can generate. So, the battery spins up a much smaller APU jet engine. High-speed bleed air from the APU is used to spin up the engine.

Once the engines are started, the APU is no longer required, but it does provide a couple of secondary functions:

-It provides cabin air and electric power before the engines are started(saving battery power).

-It provides an emergency source of electric power in the event of engine failure.

-It can start the aircraft engines mid-flight in an emergency.

Navigation lights

Beacon

Stroboscopic
Anti-collision
Landing
Taxi

Pressure information intakes

Pitot tube

Static port

Other/Unclassified

Struts

Fuel vent

Rotary-wing aircraft components

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Helicopter

Gyroplane

Although gyroplanes are designed in a variety of configurations, for the most part the basic components are the same. The minimum components required for a functional gyroplane are an airframe, a powerplant, a rotor system, tail surfaces, and landing gear. An optional component is the wing, which is incorporated into some designs for specific performance objectives.

Airframe

The airframe provides the structure to which all other components are attached. Airframes may be welded tube, sheet metal, composite, or simply tubes bolted together. A combination of construction methods may also be employed. The airframes with the greatest strength-to-weight ratios are a carbon fiber material or the welded tube structure, which has been in use for a number of years.

Landing Gear

The landing gear provides the mobility while on the ground and may be either conventional or tricycle. Conventional gear consists of two main wheels, and one under the tail. The tricycle configuration also uses two mains, with the third wheel under the nose. Early autogyros, and several models of gyroplanes, use conventional gear, while most of the later gyroplanes incorporate tricycle landing gear. As with fixed wing aircraft, the gyroplane landing gear provides the ground mobility not found in most helicopters.

propeller

The propeller provides the thrust necessary for forward flight, and is independent of the rotor system while in flight. While on the ground, the engine may be used as a source of power to prerotate the rotor system. Over the many years of gyroplane development, a wide variety of engine types have been adapted to the gyroplane. Automotive, marine, ATV, and certificated aircraft engines have all been used in various gyroplane designs. Certificated gyroplanes are required to use FAA certificated engines. The cost of a new certificated aircraft engine is greater than the cost of nearly any other new engine. This added cost is the primary reason other types of engines are selected for use in amateur built gyroplanes.

Lifting Systems

Rotor

The rotor system provides lift and control for the gyroplane. The fully articulated and semi-rigid teetering rotor systems are the most common. These are explained in-depth in Chapter 5—Main Rotor System. The teeter blade with hub tilt control is most common in homebuilt gyroplanes. This system may also employ a collective control to change the pitch of the rotor blades. With sufficient blade inertia and collective pitch change, jump takeoffs can be accomplished.

Wings

Wings may or may not comprise a component of the gyroplane. When used, they provide increased performance, increased storage capacity, and increased stability. Gyroplanes are under development with wings that are capable of almost completely unloading the rotor system and carrying the entire weight of the aircraft. This will allow rotary wing takeoff performance with fixed wing cruise speeds.

Empennage

The tail surfaces provide stability and control in the pitch and yaw axes. These tail surfaces are similar to an airplane empennage and may be comprised of a fin and rudder, stabilizer and elevator. An aft mounted duct enclosing the propeller and rudder has also been used. Many gyroplanes do not incorporate a horizontal tail surface.

On some gyroplanes, especially those with an enclosed cockpit, the yaw stability is marginal due to the large fuselage side area located ahead of the center of gravity. The additional vertical tail surface necessary to compensate for this instability is difficult to achieve as the confines of the rotor tilt and high landing pitch attitude limits the available area. Some gyroplane designs incorporate multiple vertical stabilizers and rudders to add additional yaw stability.

Other aircraft components

Airships, hot-air balloons, gliders and other kind of aircraft have specific components in their designs. They can also use airplane components (renamed or non) or even devices which do the same function but are different. Anyway, all these should be studied.