AERONAUTICAL LECTURING NOTES

What for aileron is used? How its operation? Aileron is used to make the rolling. To be more specific it creates a force at the fitted place due to aerodynamic effect, and that force causes a moment with respect to c.g.. of the aircraft. Ailerons are fitted at the two ends of the main wing. So that distance is high from center of gravity. Even though if we deflect a small amount of angle of attack to the aileron aerofoil, we will have large amount of moment . See the fig. given inside the next question. Ailerons operate on the differential mechanism. That means if the right aileron goes up, then left aileron goes down. Suppose if pilot wants to have a right turn, he must bring right aileron up. What is adverse yaw? If a pilot wants to have a right turn, then he will apply a control from the cockpit in such a way that the right aileron goes up. Say, for instance, right aileron goes 5 deg upward in AOA. Then you might think left aileron goes 5 deg downwards. If it ...

What is Magnus effect? The flow over a rotating cylinder can explain the Magnus effect better. The cylinder rotates in one direction. The flow gets high velocity in the upper half and hence less pressure. Bottom half is rotating in opposing fashion to the free stream air flow, hence air molecules going around the region gets less velocity and hence high pressure. The high pressure goes to compensate   the less pressure, then lift gets produced. The theory of production of lift from the rotating cylinder is what known to be Magnus effect. What is fan wing aircraft? Please have a read on Bernoulli’s law  for better understanding of answer. Fan wing aircraft is the one which produces lift primarily from the rotation of cylinder located in the wing span. It works based on the Magnus effect. The fan part rotates. The angular velocity of the fan accelerates the linear velocity of air molecules passing over top surface of the fan wing aerofoil. ...

What is gas turbine engine? A gas turbine is a machine delivering mechanical power or thrust. It does this using a gaseous working fluid which is continuously flowing. This working fluid is initially compressed in the compressor. It is then heated in the combustion chamber by chemical reaction. Note: lot of energy has been added to working fluid at this stage. Finally, it goes through the turbine. The turbine converts the energy of the gas into mechanical work. Part of this work is used to drive the compressor. What are the types of compressor used in gas turbine engines? Centrifugal Compressor Axial flow compressor Just name any three aircraft power-plant makers? General Electric Rolls Royce Pratt & Whitney

What is meant by I.C. engine? In this type of engine, combustion of fuel takes place within the cylinder. This type of engine includes gas engine, petrol engines and diesel engines. These are generally used for road vehicles, locomotives, and aircraft and for other industrial applications. Write the classification of I.C. engines. Based on ignition: Spark ignition Compression ignition Based on fuel: Petrol engine Diesel engine Based on cooling system: Air cooled   Water cooled  What is reciprocating engine?  An engine in which reciprocating motion of piston creates mechanical    energy, necessary to do a work.    What are the types of fuel ignition in reciprocating engine?    Spark ignition- Uses a spark plug to ignite fuel   Compression ignition- Compression will be done excessively so that when       fuel enters it can automatically ignite.     Note: Whenever we do compr...

Write down all type of power plants that are being used in aircrafts? Reciprocating engines Gas turbine engine Ramjet engine Scramjet engine What are the types of gas turbine engines? Turbo jet Turbo prop Tubo fan Turbo shaft Which gas turbine engine is fuel efficient? Turbo fan What are the components of Turbojet engine? Inlet Compressor Combustion chamber Tubine Nozzle Exhaust  Write the advantages of gas turbine power plants. The capital cost of plant is low. This can be quickly commissioned. It requires less space. Capacity to use wide variety of fuels Write the disadvantages of gas turbine power plants About two third of the power developed by the turbine is used to drive the compressor. Hence net output of plant is low. Low efficiency Needs special cooling arrangements Operating temperature is high of the order of 20000C.

What is Newtons second law and how it matches with Aircraft Engine? If some mass ‘M” is accelerated, then a force presents. Same way the mass of fuel air mixture is accelerated by a chemical reaction thus creates exhaust force. What is Newtons third law and how it matches with Aircraft Engine? For every action there is an equal but opposite reaction.  The exhaust force created is also having equal and opposite reaction called Thrust which is always in the direction of flight. What is a propeller? And how it functions? A propeller is simply a rotating aerofoil. It provides thrust in the same way as how an aerofoil mounted on wing generates lift. To know how a wing generates lift click here . When propeller rotates, the hub has to cover a least circular path whereas the tip has to travel a large circular path; in the same time. So propeller tip will be experiencing high speed than hub; that means from hub to tip speed is increasing. Suppose if we want to hav...

What are the types of rockets? Based on the fuel (Propellant) type used Solid Propellant Liquid propellant Hybrid Electric rocket Ionic rocket What is missile? Missile is same like a rocket. The purpose of use is to destroy enemies. Missile will be launched in inclined position with reference to earth horizon. In what way does a rocket differ from aircraft? Rocket is operating in space where no air (No oxygen for  combustion ) is available and also in the air. So in order to have an efficient thrust from combustion it needs to have separate tank for oxygen storage. But aircraft since it is operating in air; it has air breathing engines. 

Define shear stress and shear strain. The two equal and opposite force act tangentially on any cross sectional plane of the body tending to slide one part of the body over the other part. The stress induced is called shear stress and the corresponding strain is known as shear strain. Define- Rigidity modulus The shear stress is directly proportional to shear strain. N = Shear stress/Shear strain Define Bulk-modulus The ratio of direct stress to volumetric strain is called as Bulk modulus. K    =   Direct stress/ Volumetric strain Define- lateral strain When a body is subjected to axial load P, The length of the body is increased. The axial deformation of the length of the body is called lateral strain. Define- longitudinal strain The strain right angle to the direction of the applied load is called lateral strain. Define Poisson’s ratio. When a body is stressed, within its elastic limit, the ratio of lateral strain...

What is helicopter? Rotary wing aircraft with engine or engines (heavier than air) which can sustain in flight (within atmosphere), because of the lift produced by its rotary wings. What is the major difference between Aircraft to rotor craft? Aircraft needs runway to take-off and land whereas a rotor craft can take off and land without runway. What is spacecraft? A Fixed wing heavier than air aircraft, with engine, which can fly in space because of thrust. What is rocket? Rocket is a flying object which is operating on atmosphere as well as in space because of thrust developed by its engines.

   What is engineering? Engineering is the combination of Science and mathematics to serve for human needs. It has many divisions. Some are aerospace, computer science, civil, Electrical, Mechanical etc. Who is an Engineer? Engineers understand what people needs and design them, construct it or machine it, maintain it. Also they will have a look on cost, quality and timing. Engineer creates an object which is not present with the help of science and mathematics. What is aeronautical engineering? Understanding the concept of flying within the atmosphere, developing/creating flying objects by engineering ideas. What is aerospace engineering? Understanding the concept of flying in space as well as in atmosphere, with that knowledge they may able to design a spacecraft, rocket or they may work in space.

What is machine? A machine is any device which reduces human effort by using mechanical parts and concepts. In what are the ways we use machines? Give examples too. 1.     Machines are used to transform energy- Generator 2.     Machines are used to transfer energy from one place to other – Crank shaft 3.     Machines are used to multiply the energy- Pulley 4.    Machines can be used to multiply speed- Bicycle 5.     Machines can be used to change the direction of a force – Flag hoist What are the simple machines available? 1.     Lever 2.     Pulley 3.     wheel and axle 4.     inclined plane 5.     Screw 6.    Gear

Define force The most commonly used type of input in mechanical system is force and it is the reason for moment, torque, stress to exist. When a force acts over a body; it gets imbalanced ; and moves in the direction of applied force. Define Work Work is the output made from the input; force. Mathematically Work = Force x Distance (N-m or Joule) Define torque Torque is described as force acting along a distance (Perpendicular distance). Torque creates twisting and makes rotation. Torque = Force × distance Define friction When a body moves or tends to move over other body, a force appears between the objects of interest. This force is called friction. Friction acts opposite to the direction of motion. Mathematically F  =   µ X R F- Friction; µ- Coefficient of friction; R- Normal force acting between surfaces Define power Power = (Force x Distance) / time      ((N-m)/s) Or  Watts