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 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 layers of atmosphere? Troposphere- 0 to 10 Kms Stratosphere- 11 to 50 Kms Mesosphere-50 to 80 Kms Ionosphere-80 to 500 Kms Exosphere-500 to Infinity Kms What are the axes of an aircraft? Longitudinal Axis- Along the length of the fuselage Lateral axis- Along the length of wing span Normal axis- Mutually perpendicular to the above two axis What are the moments occuring with reference to those axes? Longitudinal axis- Rolling Lateral axis- Pitching moment Normal axis- yawing

What are the major parts of an aircraft? Main wing Tail wing Powerplant Fuselage Landing gear What is the reason for stall? Define critical angle of attack? If the angle of attack for an aerofoil increases from zero deg, you can watch the increase in lift and drag. If you keep on increasing the AOA, at some point sudden loss of aerodynamic forces will occur. Aerofoil can create aerodynamic forces in a large magnitude when attached flow of air occurs at aerofoil surface.  As the aerofoil gets increased AOA, the flow of air starts detaching from the aerofoil surface. If fully detached then no aerodynamic forces will be generated. That is what the reason for stall. The angle at which stalling starts is the critical angle of attack. What is stagnation point? Stagnation point is the point in the airflow where the velocity gets its zero magnitude because of the presence of object in airflow. The flow deviates/joins between upper and lower surface of the ...

What are the phases of flight? Takeoff Climb Cruise Descent Loiter Landing What is aerodynamic centre? Aerodynamic center is the point in the aerofoil where the pitching moment is constant even though if we change angle of attack. To solve flight dynamics problem it is the pivotal point. What is center of pressure? Centre of pressure is the point where the pitching moment is zero. When angle of attack varies cop varies. So it is tedious if we try to solve dynamics of flight by taking COP as reference.

What are the forces acting on flight? Aerodynamic forces- Lift, Drag and Side fore Propulsive force- Thrust Gravitational force- Weight Buoyancy force- Negligible When air flows over wing it creates resultant. We are solving that resultant in three mutually perpendicular axes. So we get Lift, Drag and Side force. Write down the equation for lift and drag? Lift=0.5*(density)* (square of velocity)*(Wing planform area)* (Coefficient of lift) Drag=0.5*(density)* (square of velocity)*(Wing planform area)*(Coefficient of drag) If lift increases, what will happen to drag? Since lift and drag are just the components of the single resultant force which is created because of the airflow over the aerofoil, drag increases if lift increases.

Add caption Fig 1 What is flight path? The curve which we attain by tracing  Center  of gravity( C.G.) of airplane at every second is known as Flight path. What is flight velocity? The tangent drawn to the flight path at any instant gives flight velocity. What is Relative Air flow? When aircraft moves, atmosphere stays rest. But in our dynamics approach in order to make analysis simple, we are considering aircraft to be stationary and the air as moving. So whatever the flight velocity with which we move, we will feel that much velocity against to that; that velocity is what Relative air flow velocity or free stream velocity. What is angle of attack? The angle between relative air flow and the chord line of aerofoil is the angle of attack. Fig 2 What is angle of incidence? The angle between fuselage reference line and average chord of wing is the angle of incidence. see fig. 1 for reference. you just draw chord line for th...

What is parafoil? A leading edge opened aerofoil is called as “Parafoil”. We know already that leading edge is facing into the wind for aerofoil. Since it has been opened, it just admits the air to flow inside the volume covered by the upper and lower surfaces. How aerofoil creates lift? What is bernouli's principle? How it suits to the aerofoil? Aerofoil has its upper surface curved, whereas bottom is moreover flat. Physically the curved portion accelerates the flow and so the top side airflow is getting increase in velocity. Lower surface is experiencing less velocity when comparing the upper surface. We know from Bernoulis law that for a fluid flow, if fluid velocity increases then pressure drops. In the upper we are feeling less pressure and in the bottom a high one. Bernoulis principle: Total energy of a steady flowing fluid system is constant. Ʃ E= k PE+KE= k mgh+0.5 mv 2 =k dividing both sides by volume ρgh+ 0.5ρv 2 =k High p...

What is aerodynamics? Aerodynamics is the study about the object moving in airflow. Here we will pay our attention to the airflow and also to the object immersed in the airflow. What is aerofoil? If you throw a pencil in air, you see, it flies and comes down instantly. So it is also having ability to fly. Technically speaking, every object is having some figures called Coefficient of lift, Coefficient of drag which governs its motion during flight. The shape which has more coefficient of lift and less coefficient of drag can stay in fly for more. Such a shape is what aerofoil. Aerofoil is having top surface (Upper camber) and lower surface (lower camber). Also it has leading edge and trailing edge where the two surfaces meet. Leading edge is facing to the wind. What is chord line? A line joining the leading edge of an aerofoil to the Trailing edge is known as Chord line. What is camber line? We know that aerofoil is having top surface (upper camber)and bot...