Lec

     Aircraft Structures:

1. Aircraft Materials
2. Component of Aircraft
3. Types of engines in Aircraft
4. Function of Different components

    Consideration to manufacture an Aircraft:

1. Lightweight 
2. Strength 
3. Safety 
4. Minimum cost 
5. Comfort
6. Spacing 

N.B: First 3 points depends on the material.

    Composite Materials (Alloy = Aluminium+Steel+other): A composite material is a combination of two materials with different physical and chemical properties. When they are combined they create a material that is specialized to do a certain job, for instance, to become stronger, lighter or resistant to electricity. They can also improve strength and stiffness. [Scource]

    Corrosion: Corrosion is a natural process that converts a refined metal into a more chemically stable form such as oxide, hydroxide, or sulfide. It is the gradual destruction of materials (usually a metal) by chemical and/or electrochemical reaction with their environment. [Source]

1. Steel→ Vulnerable to corrosion.
2. Stainless Steel→ Steel+protective coating of another material.
3. Alloy→Provide protection against corrosion.

    Alloy: alloys are a compound of two or more metals. The metals present in the largest amount is call base metal. Other metals added with the base metal are called alloying elements.

    Properties of Alloy: Adding the alloying elements changes the characteristics of base metal. Heat treatment can increase the strength of the alloy. Alloys have a good strength to weight ratio. Alloy provides protection against corrosion.

            strength to weight ratio =

The higher the ratio the better material it is.

    Aluminium Alloy: Generally pure aluminum is relatively soft and weak but they are very light weighted. After adding small amounts of copper, magnesium, etc. its strength increases quite a lot. They have a high strength to weight ratio. They are resistant to corrosion and easy to manufacture.

    Magnesium Alloy: magnesium is the world's lightest structural metal. It has low resistance to corrosion. Conventional aircraft do not use magnesium alloy. It is used to make helicopters. Cause high altitude means low temperature, which causes ice formation. That is a good reason for corrosion. but helicopter does not fly that much high altitude.

    Titanium Alloy: It is a lightweight, strong alloy. Resistant to corrosion. Researchers are ongoing to make titanium alloy applicable where aluminium alloy is weak. Unaffected by long exposure to seawater. Resistant to radiation. It is used in spacecraft. Amphibian aircraft.

    Steel Alloy: Is is used in some aircraft component to have higher strength. Stainless steel is used extensively. Because it is resistant to corrosion highly. Valuable in using near water.

    Plastic and Composite Materials: Various plastic materials are used in aircraft. Mainly 4 types. These are, 

1. Transparent plastic 
2. Reinforced plastic  
3. Composite plastic
4. Carbon fiber     

They are used in windshields, canopy, windows and other transparent objects. Relatively weak and scratches easily.

    

    Parts of Wing: 

1. Aileron 
2. Flaps (to generate or increase lift)
3. Spoiler (to reduce lift or sometimes drag)
4. Slats (to increase lift)   
5. Horizontal stabilizer

    Types of Aircraft Based on Wing:

1. Wing position: (i)Low wing   (ii) Mid wing   (iii) High wing 
2. Wing shape: (i) Delta   (ii) Swept   (iii)Rectangular   (iv) Tapered 
3. Number of wing:  (i) Mono   (ii) Bi-plane   (iii) Tri-plane

• Wings are the main lifting surface that supports the airplane.
• The fuselage is the central body of an airplane and designed to accommodate the crew, passenger, cargo, pilot, cockpit components. carries accessories and other equipment.
• A powerplant is a unit or machine that converts chemical energy contains in the fuel to thrust force.

    Parts of Engine: 

• Inlet: The inlets job is to intake airflow and direct the airflow to the compressor
• Compressor: Compressor is to increases the air pressure. As air passes through the compressor, the pressure gets increased.
• Combustion Chamber: The high-pressure air mixes up with the fuel and the mixture is ignited. As the mixture is burnt the high-velocity air moves towards the turbine.
• Turbine: The purpose is to move the compressor at a high speed.
• Exhaust: The air exits from the exhaust at a high velocity, pushes the aircraft forward.

    Types of Engine:

1. TurboJet (Long-range)
2. TurboFan (Mid-range)
3. TurboProp (Short range)
4. turboShaft

    Advantages of Turbojets:

• Simple design, no external propeller or fan
• Capable of highspeed.
• Takes up little space

    Disadvantages of Trubojets: 

• Not efficient 
• High fuel consumption
• Loud noise