PHAK - Chapter 3: Aircraft Construction

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Center of Gavity (CG)

The specific point where the mass or weight of an aircraft may be said to center. A point around which if the aircraft could be suspended or balanced, the aircraft would remain relatively level. Its position determines the stability of the aircraft in flight. As it moves rearward (towards the tail) the aircraft becomes more and more dynamically unstable

It should be set with fuel tanks empty. Because it is set with the fuel tanks fuel the aircraft would become unstable as the fuel is used in flight. The CG is computed during intial design and construction and is further affected by the installation of onboard equipment, aircraft loading and other factors.

In aircraft with fuel tanks situated in front of the CG, the CG should be set with the fuel tanks fuel or empty? Why?

The fuselage

Is the central body of the airplane and is designed to acommodate the crew, passengers, and cargo. It also provides the structural connection for the wings and tail assembly. Older types utilized an open truss structure constructed of wood, steel or aluminum tubing. The most popular types of structures now are the monocoque (french for "Single shell) and seminonocoque

Monoplane

Airplane with a single set of wings

Biplane

Aircraft with two sets of wings

Sesquiplane

Airplane with a lower set of wings that is smaller than the upper set of wings

Semi-cantilever

Many high-wing airplanes have external braces(tirantes), or wing struts (riostras) that transmit the fligh 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...

Full cantilever

An aircraft with wings designed to carry the loads without external struts (A few high-wing and most low-wing airplanes) is known as...

The fuel tanks

In most modern airplanes, they are either an integral part of the wing's strcuture or consist of flexible containers mounted inside of the wing

Aerostatos / Aerodinos

Clasificación general de las aeronaves

Dirigible y Globo

Ejemplos de aerostatos

Ala fija, ala batiente, ala rotativa

Division de aerodinos con sistema propulsor

Anfibio, hidroavión, avión

Ejemplos de Aerodinos con sistema propulsor de Ala fija

Ornitóptero

Ejemplos de Aerodinos con sistema propulsor de Ala batiente

Convertible, autogiro, girodino, helicóptero

Ejemplos de Aerodinos con sistema propulsor de Ala giratoria

Velero, Planeador, Parapente, y Ala Delta

Ejemplos de Aerodinos sin sistema propulsor

¿Qué son los aerostatos?

Son aeronaves que generan fuerza de sustentación mediante un fluido más ligero que el fluido en el que se mueven (Aeronaves menos pesadas que el aire)

¿Qué son los aerodinos?

Aeronaves que generan fuerzas de sustentación mediante el movimiento relativo con el fluído que les rodea (Aeronaves más pesadas que el aire). Se dividen en Aerodinos CON sistema propulsor y Aerodinos SIN sistema propulsor.

Aircraft

A device that is used, or intended to be used, for flight according to the Title 14 of the CFR part 1 (14CFR)

Airplane

Engine-driven fixed-wing aircraft that is supported in flight by the dynamic reaction of air against its wings

Advanced avionics aircraft

Aircraft that contains a Globas Positioning System (GPS) navigation system with a moving map display, in conjunction with another system such an autopilot

Thrust, Weight, Lift and Drag

Forces that act upon an aircraft in relation to straight-and-level, unaccelerated flight.

Thrust

Forward force produced by the propeller/powerplant. Acts parallel to the longitudinal axis of the aircraft. Opposes drag.

Drag

Rearward and retarding force caused by the disruption of airflow by the wing, fuselage, and other protruding objects. Opposes thrust and acts rearward parallel to the relative wind.

Weight

Combined load of the aircraft itself, the crew, the fuel and the cargo or baggage. Pulls the aircraft down because of the force of gravity. Opposes lift and acts vertically downward through the aircraft's CG.

Lift

Opposes the downward force of weight. Is produced by the dynamic effect of the air acting on the wing. Acts perpendicular to the flight path through the wing's Center of Lift (CL)

Longitudinal axis

Or "Roll" axis. Extends through the aircraft from nose to tail, with the line passing through the CG

Lateral axis

Or "Pitch" axis. Extended across the aircraft on a line through the wing tips. Passes through the CG

Vertical Axis

Or "Yaw" axis. Passses through the aircraft vertically, intersecting the CG.

Center of gravity (CG)

The specific point where the mass or weight of an aircraft may be said to center. It's the point where if the aircraft could be suspended or balanced, it would remain relatively level. Its position determines the stability of the aircraft in flight. As it moves rearward the aircraft becomes more and more dynamically unstable.

Fuselage

The central body of the airplane. Provides the structural connection for the wing and tail assembly. Older aircraft used "Open Truss". Today's aircraft are monocoque (French "Single-shell" and semimonocoque

Wings

Airfoils attached to each side of the fuselage and are the main lifting devices that support the airplane in flight. Exist in high, mid, and low (also shoulder and parasol). Depending on the number of them it can be called monoplane or biplane (also sesquiplane)

Semi cantilever / Full Cantilever

Wings that doesn't used struts or used them just until the middle of the wing. Most low wing airplanes use this configuration.

Principal structural parts of the wing

Spars (palos,mástiles), ribs (costillas), stringers (largueros). Which are reinforced by trusses (armaduras), I-beams (Vigas en I), and tubing (tubería)

Ribs of the wings

Determine the shape and thickness of the wing (Airfoil)

Ailerons

Extend from about the midpoint of each wing outward toward the tip. Move in opposite directions to create aerodynamic forces that cause the airplane to roll

Flaps

Extend from the fuselage to near the midpoint of each wing. They are normally flushed with the wing's surface during cruising flight. When extended they move simultaneouly downward to increase the lifting force of the wings for takeoffs and landings (low airspeeds)

Empennage

Include the entire tail group and consists of fixed surfaces such as the vertical and horizontal stabilizers, and movable surfaces such as the rudder, elevator and trim tabs.

Rudder

It's attached to the back of the vertical stabilizer. During flight it is used to move the airplane nose left and right.

Elevator

It's attached to the back of the horizontal stabilizer. It's used to move the nose of the airplane up and down during flight.

Trim tabs

Smaller movable portions of the control surfaces that reduce control pressures. They can be installed on ailerons, rudder or elevator.

Stabilator

One-piece horizontal stabilizer that pivots from a central hinge point. They usually have an "Antiservo" tab extendning across their trailing edge.

Antiservo tab

Moves in the same direction as the trailing edge of the stabilator and helps make the stabilator less sensitive. Also functions as a trim tab to relieve control pressures and help maintain the stabilator in the desire position.

The landing gear

Is the principal support of the airplane when parked, taxiing, taking off or landing. Can use of wheels, floats or skis.

Conventional or Tailwheen landing gear

Two main wheels and a third rear mounted wheel.

Tricycle or nosewheel landing gear

Two main wheels and a third wheel located on the nose.

The Powerplant

Usually includes both the engine and the propeller.

The Engine

Its primary function os to provide the power to turn the propeller. It also generates electrical power, provides a vacuum source for some flight intruments, and in many aircraft provides a source of heat for pilot and passengers. It's normally covered by a cowling or nacelle.

Cowling or nacelle

Its purpose is to streamline the flow of air around the engine and to help cool the engine by ducting air around the cylinders.

The Propeller

Translates the rotating force of the engine into thrust. It's a rotating airfoil that produces thrust through aerodynamic action. A high pressure are is formed ar the back of it and a low pressure are is produced at the face of it.