The four forces acts on flight .pptx

This presentation explains all the forces that acts on a flight when flys

1. What Does It Take To Fly? Explaining The Four Forces Of Flight Rebin fakhir

2. A force may be thought of as a push or pull in a specific direction. A force is a vector quantity so a force has both a magnitude and a direction. When describing forces, we have to specify both the magnitude and the direction. FORCE

3. In aircraft in straight and level flight is acted upon by four forces: Lift Thrust Gravity Drag 01 02 03 04

4. How do the forces work together? The opposing forces balance each other: lift equals gravity and thrust equals drag , any inequality between thrust and drag while maintaining straight and level flight, will result in acceleration or deceleration until the two forces again became balanced

5. 1.What is lift ? To overcome the weight force, airplanes generate an opposing force called lift. Lift is generated by the motion of the airplane through the air and is an aerodynamic force. "Aero" stands for the air, and "dynamic" denotes motion. Lift is directed perpendicular to the flight direction. The magnitude of the lift depends on several factors including the shape, size, and velocity of the aircraft. As with weight, each part of the aircraft contributes to the aircraft lift force.

6. 1.What is lift ? Most of the lift is generated by the wings. Aircraft lift acts through a single point called the center of pressure. The center of pressure is defined just like the center of gravity, but using the pressure distribution around the body instead of the weight distribution. The distribution of lift around the aircraft is important for solving the control problem. Aerodynamic surfaces are used to control the aircraft in roll, pitch, and yaw.

7. How does lift work? The air moving over the wing must travel from A to B in the same amount of time, therefore, the air is moving faster along the top of the wing This creates a difference in air pressure above and below – a phenomenon called the Bernoulli effect, the pressure pushing up is greater than the downward pressure, and lift is created

8. Factors Affecting Lift Object Motion Air Object : At the top of the figure, aircraft wing geometry has a large effect on the amount of lift generated. The airfoil shape and wing size will both affect the amount of lift. The ratio of the wing span to the wing area also affects the amount of lift generated by a wing.

9. Factors Affecting Lift Object Motion Air Motion : To generate lift, we have to move the object through the air. The lift then depends on the velocity of the air and how the object is inclined to the flow.

10. Factors Affecting Lift Object Motion Air Air : Lift depends on the mass of the flow. The lift also depends in a complex way on two other properties of the air: its viscosity and its compressibility

11. W hat is gravity ? Weight is a force that is always directed toward the center of the earth. The magnitude of the weight depends on the mass of all the airplane parts, plus the amount of fuel, plus any payload on board (people, baggage, freight, etc.). The weight is distributed throughout the airplane. But we can often think of it as collected and acting through a single point called the center of gravity. In flight, the airplane rotates about the center of gravity.

12. W hat is gravity ? Flying encompasses two major problems; overcoming the weight of an object by some opposing force, and controlling the object in flight. Both of these problems are related to the object's weight and the location of the center of gravity. During a flight, an airplane's weight constantly changes as the aircraft consumes fuel. The distribution of the weight and the center of gravity also changes. So the pilot must constantly adjust the controls to keep the airplane balanced, or trimmed.

13. How does gravity help the flight of a paper airplane? Gravity helps create lift for paper airplanes. Gravity is the force that pulls objects toward the Earth. Lift is the force that pushes an aircraft into the air. When paper airplanes are thrown up, gravity pulls them down. This movement causes a difference of air pressure on the airplane wings, which then causes lift. Bernoulli's Principle explains how a difference of air pressure is caused due to air moving faster on top of the wings than on bottom. It is because of gravity that paper airplanes are able to produce this difference and glide!

14. factors that affect gravity mass distance Objects with more mass have more gravity. ... So, the closer objects are to each other, the stronger their gravitational pull is. Earth's gravity comes from all its mass. All its mass makes a combined gravitational pull on all the mass in your body.

15. How does gravity help the flight of a paper airplane? Gravity helps create lift for paper airplanes. Gravity is the force that pulls objects toward the Earth. Lift is the force that pushes an aircraft into the air. When paper airplanes are thrown up, gravity pulls them down. This movement causes a difference of air pressure on the airplane wings, which then causes lift. Bernoulli's Principle explains how a difference of air pressure is caused due to air moving faster on top of the wings than on bottom. It is because of gravity that paper airplanes are able to produce this difference and glide!

16. What does the small wing on the tail of an airplane do? The horizontal stabilizer, or rear wing, helps keep the airplane in level flight. This means it prevents the nose from tilting up or down, keeping the center of lift over the center of gravity. Without the stabilizer, the airplane's center of gravity is forward of the wing's center of lift. In other words, the nose tilts down because it's heavier than the tail, which makes the airplane unbalanced. The horizontal stabilizer also holds one of the plane's control surfaces known as the elevator. The elevator helps the airplane pitch up or down. Not all airplanes have a wing in the back, and some don't have one at all.

17. What Is Thrust ? To overcome drag, airplanes use a propulsion system to generate a force called thrust. The direction of the thrust force depends on how the engines are attached to the aircraft. In the figure shown above, two turbine engines are located under the wings, parallel to the body, with thrust acting along the body centerline. On some aircraft, such as the Harrier, the thrust direction can be varied to help the airplane take off in a very short distance. The magnitude of the thrust depends on many factors associated with the propulsion system including the type of engine, the number of engines, and the throttle setting.

18. What Is Thrust ? For jet engines, it is often confusing to remember that aircraft thrust is a reaction to the hot gas rushing out of the nozzle. The hot gas goes out the back, but the thrust pushes towards the front. Action <--> reaction is explained by Newton's Third Law of Motion. The motion of the airplane through the air depends on the relative strength and direction of the forces shown above. If the forces are balanced, the aircraft cruises at constant velocity. If the forces are unbalanced, the aircraft accelerates in the direction of the largest force.

19. How is thrust used during flight? Thrust is used to overcome the drag of an airplane, and to overcome the weight of a rocket.

20. FACTORS AFFECTING THRUST Air Density Altitude Airspeed Ram Effect Engine RPM Density is the mass of a substance per unit of its volume. According to the thrust equation, if the mass of airflow increases, thrust will increase. If the density of air increases, mass will increase, and therefore thrust will increase. As an aircraft operates at various altitudes and climates, the ambient air temperature and pressure will vary. These factors will affect the density of the air entering the engine, and as a result, will affect thrust.

21. FACTORS AFFECTING THRUST Air Density Altitude Airspeed Ram Effect Engine RPM As an aircraft climbs, pressure and temperature will normally drop. From the previous discussion, thrust will decrease with a pressure decrease, and thrust will increase with a temperature decrease. With an increase in altitude , however, the rate of thrust decreases because a pressure drop is greater than the thrust increase resulting from a temperature drop. This means an engine will produce less thrust as it increases in altitude.

22. FACTORS AFFECTING THRUST Air Density Altitude Airspeed Ram Effect Engine RPM In the thrust equation, the difference between the inlet and exhaust velocities plays a major role in determining thrust available. As the inlet velocity (v initial) approaches the magnitude of the exhaust velocity (v final), thrust is reduced. Therefore, if the mass of air and fuel is held constant, thrust will decrease as airspeed increases. This decrease in thrust due to an increase in airspeed is theoretical

23. FACTORS AFFECTING THRUST Air Density Altitude Airspeed Ram Effect Engine RPM If we only consider the change in airflow velocity in the thrust equation, then thrust decreases with an increase in airspeed. Remember, that the thrust equation consists of two variables: mass (m) and acceleration (v final – v initial). As mentioned, the difference between inlet and exhaust velocities decreases as the aircraft increases speed. However, more and more air is being rammed into the inlet, increasing the mass and pressure of inlet air. This offsets the decrease in acceleration and results in a neutral effect or slight increase in thrust at subsonic airspeeds.

24. FACTORS AFFECTING THRUST Air Density Altitude Airspeed Ram Effect Engine RPM This is due to the compressibility of airflow as velocity increases toward supersonic. As airflow becomes compressible, mass due to ram effect increases at an increasing rate. Ram effect is especially important to high performance aircraft due to the exceptionally high mass airflow that occur at supersonic speeds. This results in a significant increase in overall thrust due to ram effect at supersonic speeds. For many high-performance fighter aircraft, ram effect allows excellent high altitude performance, although air density is low.

25. FACTORS AFFECTING THRUST Air Density Altitude Airspeed Ram Effect Engine RPM One of the most obvious factors that affects the thrust output is the rotational speed of the engine. With an increase in RPM , there is an increase in thrust. However, at low RPM there is very little increase in thrust with an increase in throttle. At higher rates of revolution, a small increase in throttle setting will produce a large increase in thrust. At the lower settings, fuel consumption is high for the amount of thrust produced. For this reason, gas turbine engines are normally operated at near their maximum RPM.

26. What is drag ? As the airplane moves through the air, there is another aerodynamic force present. The air resists the motion of the aircraft and the resistance force is called drag. Drag is directed along and opposed to the flight direction. Like lift, there are many factors that affect the magnitude of the drag force including the shape of the aircraft, the "stickiness" of the air, and the velocity of the aircraft. Like lift, we collect all of the individual components' drags and combine them into a single aircraft drag magnitude. And like lift, drag acts through the aircraft center of pressure.

27. Is drag necessary for flight to be achieved? Drag is the force that pushes planes backwards and slows them down as they fly through the air. Many current innovations in flight are focused on decreasing drag on planes as much as possible. With less drag, planes are able to achieve faster speeds with the same amount of thrust as they had before.

28. Technically, drag is not necessary for flight to be achieved. However, it is impossible to completely eliminate drag during flight without eliminating air. Air is needed to generate lift, so although drag is not completely necessary for flight, an airplane that achieve’s lift will always experience some form of drag

29. Factors affecting drag force Object Motion Air Geometry has a large effect on the amount of drag generated by an object . As with lift, the drag depends linearly on the size of the object moving through the air. The cross-sectional shape of an object determines the form drag created by the pressure variation around the object.

30. Factors affecting drag force Object Motion Air The three dimensional plan form shape affects the induced drag of a lifting wing. If we think of drag as aerodynamic friction, the amount of drag depends on the surface roughness of the object ; a smooth, waxed surface produces less drag than a roughened surface. This effect is called skin friction and is usually included in the measured drag coefficient of the object.

31. Factors affecting drag force Object Motion Air Drag is associated with the movement of the aircraft through the air, so drag depends on the velocity of the air. Like lift, drag actually varies with the square of the relative velocity between the object and the air. The inclination of the object to the flow also affects the amount of drag generated by a given shaped object

32. Factors affecting drag force Object Motion Air If the object moves through the air at speeds near the speed of sound, shock waves are formed on the object which create an additional drag component called wave drag. The motion of the object through the air also causes boundary layers to form on the object. A boundary layer is a region of very low speed flow near the surface which contributes to the skin friction.

33. Factors affecting drag force Object Motion Air Drag depends directly on the mass of the flow going past the aircraft. The drag also depends in a complex way on two other properties of the air : its viscosity and its compressibility.

34. Relationship between those forces that are required to flight Lift must be greater than weight( gravity ) for a plane to take off Thrust must be greater than drag for a plane to take off Lift must be less than weight( gravity ) for a plane to land Thrust must be less than drag for a plane to land