Introduction to aircraft components – wikiversity gas house edwards co


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 aircrafts the empennage is built from the cabin pressure-cone and may contain the Flight Data Recorder ("black box"), Cockpit Voice Recorder and the pressure out-flow valve.

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.

As aircraft move in three dimensions we need various control devices to control it. Fix-wing aircrafts 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 maximmun strength and response using small moving parts thanks to the lever concept.

The vertical stabilizer functions with the same principle a wing does, but being symmetrical. It is a 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 the stabilizer since it’s movement is equal to change the angle of attack of this ‘wing’.

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 in two parts crossing the vertical stabilizer. Some horizontal stabilizers have no elevators but are a whole elevator (mainly in gliders, since it has a better aerodynamic performance). In Canard-configuration planes, the horizontal 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).

Piston engines are common four-stroke cycle engines Of course they are dessigned 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.

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.

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.

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.

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.

The powerplant 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.

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.

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.

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