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How Airplanes are Built (Private Pilot)

In Title 14 CFR part 1, it states that an aircraft is a device used or intended to be used for the purpose of flight.  The categories of aircraft used to obtain an airmen certification are:

  • Airplane

  • Rotorcraft

  • Glider

  • Lighter-than-air (Balloon or Blimp)

  • Powered-lift

  • Powered parachute

  • Weight shift control aircraft

 

Lift and Basic Aerodynamics

​There are, four force’s that act on an aircraft during straight-and-level and un-accelerated flight.

  • Thrust –is the forward force from the powerplant and is opposite and overcomes drag.

  • Drag – is the rearward force caused by disrupted airflow from the wings, fuselage, etc. and is opposite of thrust.

  • Weight – is the downward force caused by gravity and additional items such as fuel, cargo, crew, etc. and is opposite of lift.

  • Lift – is the upward force created by the airflow around the wings, and is opposite of weight.

 

Major Aircraft Components

​Almost all aircraft are designed and built with the same structural components.

  • Fuselage

  • Wings

  • Empennage

  • Landing gear

  • Powerplant

Fuselage:

The fuselage is the main body and connecting point for all the other components.  It is designed to hold the crew, passengers, and cargo. 

There are two types of fuselage structures used in today’s aircraft designs.

  • Monocoque – is a very strong construction, which uses the skin to support the load. This construction is not recommended, do to twisting and bending stresses are carried by the external skin.

  • Semimonocoque – use a structure to attach the skin too.  It uses a combination of bulkheads, stringers, and formers to make the shape of the fuselage.

The semimonocoque fuselage is designed with a main section to attach the wings along with firewalls built in, such as a firewall built between the engine and the flight deck, on small single engine aircraft.

Wings:

The wings are also called airfoils; they are attached on either side of the fuselage and creates the lifting force of the airplane. The wings may be attached at either the bottom, top or middle of the fuselage also known as low-wing, high-wing or mid-wing.

The wings construction is made up of the skin, spars, ribs, and stringers. The fuel tanks are built into the wing and the primary and secondary flight controls are attached to the wings.

Flaps are attached at the tailing edge of the wing and are extended outward and downward to increase lift during takeoff and landings.  There are multiple types of flaps used, but only four basic designs.

Empennage:

The empennage is the entire tail section of the airplane.  It is made up of the vertical stabilizer which the rudder and trim tab is attached to, and the horizontal stabilizer which the elevator and its trim tab is attached.

Landing Gear:

The landing gear is the main support for the airplane while it is parked or when the airplane is taxiing, takeoff and landing.

The landing gear maybe equipped with wheels, floats for water or skies for the snow.

There are two types of landing styles

  • Conventional landing gear – also known as the tailwheel

  • Tricycle gear – is when the third wheel is mounted at the nose, it called the nose wheel.

 

Powerplant:

The powerplant is a combination of the engine and the propeller.  The main function of the powerplant is to turn the propeller; it also supplies electrical power, heat and a vacuum for some instruments.  

The engine is covered by a cowling or nacelle, which streamlines the airflow around the engine, and helps cool the cylinders on piston engines.

 

Subcomponents

The subcomponents of aircraft include the airframe, electrical systems, flight controls, and the brakes.

The airframe is the most basic structure of the aircraft itself.  The airframe is designed to hold and withstand all aerodynamic forces and stress imposed by the extra weight of fuel, crew, and payload the aircraft carries.

The electrical systems function is to generate and produce electrical power thought out the aircraft. The purpose of the electrically system is to provide power to the flight instruments, aircraft lighting, anti-icing and much more. The source of power is supplied by a few different types of sources:

  • Engine-driven alternating current (AC) generators

  • Auxiliary power units (APUs)

  • Or an external power source 

The flight controls are devices that are used to control the aircrafts attitude and maintain a curtain flight path during flight.  Flight controls are operated by the pilot or may also be operated by an auto pilot system.

Aircraft brakes on modern aircraft are designed to absorb enormous amounts of energy during landing.

The brakes consist of: Multiple pads (Called calipers) that are operated by an independent hydraulic system which squeeze them together on to the rotating disk (rotor). The rotor is turning the wheels,

as a result when the pads are squeezing together they are

applying friction to the rotor allowing the wheels to slow down

and or stop turning.

 

References

PHAK Ch. 3

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Tricycle

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