Common airplane structural components include the fuselage, wings, an empennage, landing gear, and a powerplant.
The fuselage is the central body of an airplane and is designed to accommodate the crew, passengers, and cargo. It also provides the structural connection for the wings and tail assembly..
Wings are airfoils normally 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 aircraft manufacturers. Each design fulfills a certain need with respect to the expected performance for the airplane. We will discuss how the wing produces flight in a later video all about aerodynamics.
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. 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 help to spread the wing loading to the fuselage for additional support. 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.
The principal structural parts of the wing are spars, ribs, and stringers. These are reinforced by trusses, I-beams, tubing, or other devices, including the skin. In most modern airplanes, the fuel tanks are either an integral part of the wing’s structure, or consist of flexible containers mounted inside of the wing.
Attached to the rear or trailing edges of the wings are two types of control surfaces referred to as ailerons and flaps. Ailerons extend from about the midpoint of each wing outward toward the tip, and move in opposite directions to create aerodynamic forces that cause the airplane to roll.
Flaps extend outward from the fuselage to near the midpoint of each wing. The flaps are normally flush with the wing’s surface during cruising flight. When extended, the flaps move simultaneously downward to increase the lifting force of the wing for takeoffs and landings.
The empennage includes the entire tail group and consists of the vertical stabilizer and the horizontal stabilizer, rudder, elevator, and one or more trim tabs.
The rudder is attached to the back of the vertical stabilizer. During flight, it is used to move the airplane’s nose left and right. The elevator, which is attached to the back of the horizontal stabilizer, is used to move the nose of the airplane up and down during flight.
Trim tabs are small, movable portions of the trailing edge of the control surface. These movable trim tabs are controlled by the pilot to reduce control pressures during flight. Trim tabs may be installed on the ailerons, the rudder, and/or the elevator.
The landing gear is the principal support of the airplane when operating on the ground, taking off, or landing. The most common type of landing gear consists of wheels, but airplanes can also be equipped with floats for water operations, or skis for landing on snow.
The landing gear consists of three wheels—two main wheels and a third wheel positioned either at the front or rear of the airplane. A landing gear configuration with a rear mounted wheel is called conventional landing gear.
When the third wheel is located on the nose, it is called a nosewheel, and the design is referred to as a tricycle gear. A steerable nosewheel or tailwheel permits the airplane to be controlled while on the ground. Most aircraft are steered by moving the rudder pedals, whether nosewheel or tailwheel. Additionally, some aircraft are steered by differential braking.
The primary function of the engine is to provide the power to turn the propeller. It also generates electrical power, provides a vacuum source for some flight instruments, and in most single-engine airplanes, provides a source of heat for the pilot and passengers.
The purpose of the cowling or nacelle is to streamline the flow of air around the engine and to help cool the engine by ducting air around the cylinders.
The propeller, mounted on the front of the engine, translates the rotating force of the engine into thrust. As you will recall from the previous video, thrust is a forward acting aerodynamic force that helps move the airplane through the air.
A propeller is a rotating airfoil that produces thrust through aerodynamic action. Propellers are usually matched to a specific aircraft/powerplant combination to achieve the best efficiency at a particular power setting.
-Lesson derived from Pilot's Handbook of Aeronautical Knowledge-
