Characteristics of aircraft Structure:-
- Marine aircraft are built to meet certain specified requirements. These requirements must be selected so they can be built into one aircraft.
- One aircraft can't possess all characteristics; just as an aircraft can't have the comfort of passenger transport and the maneuverability of a fighter.
- Each type of aircraft determines however strong it should be built.
- The Navy fighter should be quick, maneuverable(well controlled), and equipped for attack and defend. To satisfy these requirements, the aircraft is extremely powerful and features a very strong structure.
The airframe of a fixed-wing aircraft consists of the following five major units:
- Fuselage
- Wings
- Stabilizers
- Flight controls surfaces
- Landing gear
A rotary-wing aircraft consists of the following four major units:
- Fuselage
- Landing gear
- Main rotor assembly
- Tail rotor assembly
Construction of aircraft:-
Components of an aircraft & their functions
Working of Airframe:-
FUSELAGE:-
A fuselage is the main structure, or body, of the aircraft. It provides space for staff, cargo, controls, and most of the accessories. The power plant, wings, stabilizers, and landing gear are included.
There are two general types of fuselage construction—
1. Monocoque:-
The true monocoque construction uses formers, frame assemblies, and bulkheads to create a fuselage structure. However, the skin carries the primary stresses/pressures. Since no bracing members are present, the skin ought to be strong enough to keep the fuselage rigid. The biggest problem in monocoque construction is maintaining enough strength while keeping the weight within limits.
2. Semi monocoque:-
- Semi monocoque design overcomes the strength-to-weight problem of monocoque construction. In addition to having designers, frame assemblies, and bulkheads, the semi-monocoque structure has the skin strengthened by longitudinal members.
- An aircraft should be constructed of materials that are each lightweight and strong. Early aircraft were made of wood. Lightweight metal alloys with greater strength than wood are developed and used in the latest aircraft.
WINGS:-
Wings develop the major portion of the lift of a heavier-than-air aircraft. The wing structures carry some of the heavier loads found in the aircraft structure. The particular design of a wing depends on many factors, such as the size, weight, speed, rate of climb, and use of the aircraft.
STABILIZERS:-
The stabilizing surfaces of aircraft carries with it vertical and horizontal airfoils. They are known as the vertical stabilizer (or fin) and horizontal stabilizer. These 2 airfoils, beside the rudder and elevators, type a part of the tail section. For inspection and maintenance purposes, the entire tail section is considered a single unit called the empennage.
LANDING GEAR:-
It is the framing of an aircraft or spacecraft and can be used for either takeoff or landing. For aircraft, it is generally needed for both. It was also formerly called alighting gear by some manufacturers.
 |
| Landing-gear-(a)Multibody-model (b)main structural components |
Aircraft Materials:-
Currently used in aircraft construction of aircraft are classified as either metallic materials or non-metallic material.
 |
| Composite materials in aircraft component |
METALLIC MATERIALS:-
The most common metals used in aircraft construction are aluminum, magnesium, titanium, steel, and their alloys.
Alloys:-
Alloy is made of two or more metals. The metal present in the alloy in the largest amount is called the base metal.
- All alternative metals added to the base metal are called alloying parts. Adding the alloying components could end in a modification within the properties of the base metal.
- For example, pure aluminum is comparatively soft and weak. However, adding tiny amounts of copper, manganese, and magnesium can usually increase the strength of aluminum many times.
- Heat treatment can increase or decrease the strength and hardness of the alloy.
- Alloys are important to the aircraft industry. They provide building materials with properties that pure metals don't possess.
Aluminum:-
Aluminum alloys are widely used in the construction of modern aircraft. Its alloys are important because they have a high strength-to-weight ratio. Aluminum alloys are resistant to corrosion and comparatively easy to fabricate. An outstanding characteristic of aluminum is its lightweight.
Magnesium:-
Magnesium is the lightest metal in the world. It is a silvery-white material that weighs two-thirds as much as aluminum. Magnesium is used to make helicopters. Magnesium's low resistance to corrosion and corrosion has reduced its use in conventional aircraft.
Titanium:-
Titanium is a lightweight, strong, corrosion-resistant metal. Recent developments make titanium ideal for applications where aluminum alloys are too weak and stainless steel is too heavy. Additionally, titanium is unaffected by long exposure to seawater and the ocean-atmosphere (the marine atmosphere).
Steel Alloys:-
Alloy steels used in aircraft construction have great strength, more so than other fields of engineering would require. These materials should withstand the forces that occur from modern aircraft. These steels contain small percentages of carbon, nickel, chromium, vanadium, and molybdenum. High-tensile steels will stand the stress of 50 to 150 tons per square inch without fail. Such instruments are made of tubes, rods, and wires. Another type of steel used is stainless steel. Stainless steel resistant to corrosion and is particularly important for use in or near water.
NONMETALLIC MATERIALS:-
In addition to metals, various types of plastic materials are found in aircraft construction. Some of these plastics include transparent plastic, reinforced plastic, composite materials, and carbon-fiber materials.
Transparent Plastic:-
Transparent plastic is used in canopies, windshields (front window), and alternative transparent enclosures. You would like to handle transparent plastic surfaces carefully as a result of they're relatively soft and simply scratched. At approximately 225°F, transparent plastic becomes soft and flexible.
Reinforced Plastic:-
Reinforced plastic is used in the construction of radomes, wingtips, stabilizer tips, antenna covers, and flight controls. It has a high strength-to-weight ratio and is resistant to mildew and rot. Because it is easy to fabricate. it is equally suitable for other parts of the aircraft. Reinforced plastic is a sandwich-type material. It is made up of two outer facings and a center layer.