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From the Ground Up - Ebook download as PDF File .pdf), Text File .txt) or read book PART I: AIRCRAFT OPERATIONS The Airplane Theory of Flight Flight. nov better aerobatics pdf from the ground up book online aviation weather jeppesen pdf the flying handbook aircraft systems for pilots jeppesen pdf. Hi, I have a copy of FTGU but I would like the PDF version so I can print off a copy to make notes on. My computer is too slow to download.
A nose down attitude is achieved by rotating the tail aft. An airplane structure in flight is subjected to many stresses due to the varying loads that may be imposed. One of the characteristics of a gyroscope is rigidity in space. If the angle of attack is increased. This disturbed air exerts a resistant force against the forward motion of the wing.
Thus, looking up a topic is now quicker than ever. Various images have been improved, many to a very significant degree. Also, extensive attention has been put towards the layout of tabular information. Several new tables have been added to the book. American Books. French Publications. Charts 56 - Day Publications Effective April 25 to June 20, Copa Collection. Flight Caps. Used in seaplane construction. Susceptible to corrosion but can be treated by anodizing.
Very corrodible in sea water. Mild steels can be hardened. Used for ribs. Fabric is also used as the covering of wings whose spars and ribs are either all wood or all metal or a combination of both. Airplane wings are subjected to compression stresses. There are five distinct types of stress: Fretting Corrosion occurs when there is a slight movement between close fitting metal parts. A wire stretched is another example of strain.
This type is more serious. The movement destroys any protective film on the metal surface and also produces fine particles of metal and oxide that tend to absorb and retain moisture. A screwdriver is subjected to severe torsional stress when forcing a screw into hardwood.
Bracing wires in airplanes are usually in tension. Corrosion fatigue is a type of stress corrosion that occurs where cyclic stresses are applied to a part or assembly. A number of surface treatments have been developed to reduce or eliminate corrosion.
It is caused by chemical or electrolytic action between the alloys in the metal itself. It may not become visible until considerable damage has been done. If the small box is crushed. The action consists of the dissolving of the surface by oxidation. There are a number of different types of corrosion. The blades of scissors exert a shear stress on a piece of paper. Such oxidation is easy to detect. Dissimilar Metals. Stress corrosion is not easy to detect until cracks begin to appear.
Landing gear must be made to withstand torsional stresses. It may be removed and the surface treated with some preventative so further damage will not occur.
These stresses produce pores or cracks in the surface coating which allow moisture to penetrate. Surface protection aids very little in the prevention of this type of corrosion.
Parts that are susceptible to stress corrosion are over tightened nuts in plumbing fittings. Steel parts are protected by cadmium plating. This is produced by atmospheric conditions due to the moisture in the air. The effect is worse in the vicinity of salt water. When metals of different chemical properties are in contact in the presence of moisture. The attack may take place over an entire metal surface or it may be penetrating in nature. The affected parts must be removed and replaced.
When a metal part is overstressed over a long period of time under corrosive conditions. Stress Corrosion. Aluminium alloys are usually anodized. A pressure of your hand on the surface of. In flight. The additional loading imposed is called a live load.
The load factor is the ratio of the actual load acting on the wings to the gross weight of the airplane. Aircraft spars. See Ultra-Lights in Chapter Airmanship. Excessive deflection or bending under a load may lead to a loss of control with serious consequences.
Strength and lightness are essential in the structure of an airplane. In most manoeuvres. When an airplane is in level flight. To attain uniform and adequate structural safety.
Lack of rigidity may also lead to flutter. The narrow margin of safety permitted by weight limitations in airplanes makes it necessary that every member must bear its proper share of the load in every condition of flight. The wings must support not only the weight of the airplane but also additional loads imposed during manoeuvres. An airplane structure in flight is subjected to many stresses due to the varying loads that may be imposed.
Another factor almost as essential as strength is rigidity. This is a rolling or weaving motion which arises when a deflection of a part of the structure causes the air forces on it to change in synchronism with its natural period of vibration.
To prevent flutter. The weight of an airplane standing on the ground or its weight due to gravity alone is commonly referred to as a dead load. The load factor is then said to be 1. This is a complicated mathematical process. The load imposed on the wings depends on the type of flight. Such a determination of loads is called a stress analysis..
This problem is complicated by the fact that an airplane structure must be light as well as strong. Flutter is most likely to occur in wings and control surfaces and may lead to structural failure. The definition of wing loading may be slightly modified for particular applications. In this case. There are. These are usually referred to as limit load factors. On the other hand. Gust Load. If an airplane is heavily loaded. The flight manoeuvres which impose high load factors are: Weight also can result in high load factors.
Because the heavy airplane is steady even in rough air. If the total lift were to exceed the total weight by a factor of 2. In flying a heavily loaded airplane. Gusts are rapid and irregular fluctuations of varying intensity in the upward and downward movement of air currents. In any degree of turbulence. See Gust Load below. Therefore when doing aerobatics always be sure that the airplane is lightly loaded.
A load factor of 3 is often expressed as An airplane in a rising or descending current of air is not affected. In an airplane that is flying at twice its stall speed. In a 60 degree bank. The lift is then in excess of the weight. Because of this. Airplanes which fly at several times their stalling speed are subject to excessive g loads in some circumstances.
When an airplane flies out of a down-gust and immediately into an up-gust. This is known as a gust load. The fact that it is sometimes possible to exceed these limits is evidence of the safety factor that is incorporated in all aircraft designs. The landing load factor in this case would be 3. In a hard landing. While it is important to worry about subjecting the airplane to excessive structural loads when flying in turbulence.
Most general aviation. This speed is below VA but well above the stall. In fact. Vertical air. This airspeed guarantees that the airplane will stall at the limit load factor. On encountering any degree of turbulence. In the first place. This is the maximum speed at which full deflection of the controls can be made without exceeding the design limit load factor and damaging the airplane primary structure. A further consideration is the fact that the published manoeuvring speed is valid only when the airplane is at gross weight.
All of these factors demonstrate that the safest airspeed at which to penetrate turbulence is one that is somewhat less than the published manoeuvring speed and.
The power-on stall speed of an airplane is significantly less than its power-off stall speed. Rapid airspeed fluctuations of 5 to 15 knots in light turbulence and up to 25 knots in severe turbulence can be expected.
Because stall speed decreases as weight decreases and because the manoeuvring speed is a function of stall speed. The airplane designer determines the manoeuvring speed by a formula that multiplies the flaps-up. The lightly loaded airplane is accelerated more easily by gusts.
Do not try to maintain altitude. The airspeed at which to fly in turbulence is therefore a compromise between structural and controllability margins. The manoeuvring speed works out to be 1. In the second place. For this reason. The faster the airplane is going. Having adequate control to recover from the lateral and directional upsets that are the result of excessive turbulence requires flying at an airspeed at which the control surfaces are effective.
The accepted procedure for flight in turbulence is to keep the wings level. In certain cases. Flight time is defined as the total time from the moment an airplane first moves under its own power for the purpose of taking off until the moment it comes to rest at the end of the flight. Although the Air Regulations do not require it. These facts relating to loads are of critical importance and should be understood and intelligently applied so that you never impose loads on any airplane that you might be flying in excess of the limit load for which it was designed.
Air time is defined as the period of time commencing when the airplane leaves the supporting surface and terminating when it touches the supporting surface at the next point of landing.
Flight time is the time pilots should record in their log books. Air time and flight time should be recorded to the nearest 5 minutes e. Safety is unlikely to be jeopardized unless the airplane has undesirable stall characteristics or is flying near to the ground as during the approach to landing when a stall can result in an accident. Do try to maintain attitude and airspeed. In most instances. All maintenance. A record of both flight time and air time and particulars of every flight is kept in a suitable Aircraft Journey Log.
In these instances. It is quite possible in turbulent conditions for the airplane to stall. If lift. That is to say. He will comprehend the various loads to which an airplane of a particular design may be exposed while flying under abnormal or adverse conditions of flight.
Every one of these airplanes has different flight characteristics. The resistance to forward motion directly opposed to thrust. He will understand how best to handle each airplane as a result of his knowledge of the theory of design. Some are single seaters carrying only the pilot.
Theory of Flight… Why learn about Theory of Flight? The pilot today has a large variety of airplanes from which to choose. Others perhaps do not yet have adequate answers. Equilibrium refers to steady motion and not to a state of rest.
The information that comprises this chapter can only be considered an introduction to a substantial but fascinating study. If either of these forces becomes greater than the force opposing it. The downward force due to gravity. If drag is greater than thrust.
New theories are forever being put forward. If a pilot has a good grasp of the fundamentals of flight. If thrust is greater than drag.
LIFT If you consider the definitions cited by air authorities. Some airplanes have laminar flow airfoil sections. The study of theory of flight and aerodynamics can be a lifetime proposition. Some questions have answers that are difficult to find. These are thrust.
When thrust and drag are equal and opposite. If weight is greater than lift. The force upward which sustains the airplane in flight. Not only to get the best performance but also to ensure the safety of each flight.
Ponder the idea a moment and it may not appear quite as absurd as it seems at first glance. Some of these airplanes may fly at less than knots top speed while others are capable of speeds well into the hundreds of knots.
Let us first consider the force of lift. The force exerted by the engine and its propeller s which pushes air backward with the object of causing a reaction.
A kite is an inclined plane. At the same time. In exerting a downward force upon the air. It is this reaction that lifts the weight of the airplane. Third Law called. It has been found that the most suitable shape for producing lift is a curved or cambered shape.
Air is heavy. An Airfoil Section. Think of a water ski or surfboard planning over the water. Remember Newton's Third Law. The reaction produced by the downwash is therefore significant. Airfoils An airfoil. The introduction of an airfoil into the streamlined airflow alters the uniform flow of air. Usually the upper surface has a greater camber than the lower.
The wings of an airplane are so designed that when moved through the air horizontally. As the air passes over the wing towards the trailing edge. Newton's Second Law states that a force must be applied to alter the state of uniform motion of a body.
Air flowing around an airfoil is subject to the Laws of Motion discovered by Isaac Newton. The airfoil is the force that acts on the body in this case. If we substitute for the string.
The camber of an airfoil is the curvature of the upper and lower surfaces. How Is Lift Created What. This flow is called downwash. In other texts. The upper half of this imaginary tube is the undisturbed airflow above the wing.
Relative airflow is created by the motion of the airplane through the air creates relative airflow. If the wing is moving forward horizontally. It is also created by the motion of air past a stationary body or also creates it or by a combination of both.
Take the example of water flowing through a venturi tube. Air flowing over the wing's upper surface accelerates as it passes through the constricted area just as it does in the venturi tube.
Being incompressible. Airflow over an Airfoil. Scientist Daniel Bernoulli discovered that the total energy in any system remains constant. It a wing is moving forward and downward. The moving water has energy in the form of both pressure and speed.
Air is a fluid. Relative Airflow Relative airflow is a term used to describe the direction of the airflow with respect to the wing. The flight path and the relative airflow are. Pressure Distribution over an Airfoil.
The result is a decrease in pressure on the upper surface of the wing that results in the phenomenon known as lift. The phenomenon defined by Bernoulli's Principle also has an effect in the production of lift by the wing moving though the air. As such. Picture the curved upper surface of a wing as the bottom half of a venturi tube. Within the venturi tube. If we consider all the distributed pressure to be equivalent to a single force. Beyond this angle. As the angle of attack is increased.
The point where this line cuts the chord of an airfoil is called the centre of pressure. WEIGHT The weight of an airplane is the force which acts vertically downward toward the centre of the earth and is the result of gravity.
This is the point through which the resultant of the weights of all the various parts of the airplane passes. The direction and speed of the wind have no effect on relative airflow. The envelopes indicated in Fig. Angle of Attack. These exist only in close proximity to the surfaces. Beyond this point. Just as the lift of an airplane acts through the centre of pressure. Angle of Attack and Centre of Pressure The angle at which the airfoil meets the relative airflow is called the angle of attack See Fig.
In Fig. They represent the comparative distribution of pressure as determined by pressure plotting. The movement of the centre of pressure causes an airplane to be unstable.
Since drag is a force directly opposed to the motion of the airfoil and. There are several ways to produce this force. Although parasite drag can never be completely eliminated.
In addition. The vertical component OL is the lift and is used to support the weight of the airplane. For an airplane to maintain steady flight. Wing struts have been eliminated in favour of fully cantilevered wings.
Drag is of two principal types. Skin friction refers to the tendency of air flowing over a body to cling to its surface. DRAG Drag is the resistance an airplane experiences in moving forward through the air. One method is to eliminate altogether those parts of the airplane that cause it. Forces acting on an Airfoil. Skin friction can be. Form drag refers to the drag created by the form or shape of a body as it resists motion through the air.
The horizontal component OD is the drag. A full description of engines and propellers will be found in the Chapter Aero Engines. The effect is the same whether the thrust is produced by a propeller moving a large mass of air backward at a relatively slow speed or by a jet moving a small mass of air backward at a relatively high speed.
OR is the resultant reaction of these two components. Another method is to streamline those parts that cannot be eliminated. Parasite drag may be divided into two components. Induced drag can be reduced only during the initial designing of an airplane. Wing-tip Vortices. These are called wing-tip vortices.
This disturbed air exerts a resistant force against the forward motion of the wing. As the decreased pressure over the top of the wing is less than the atmospheric pressure around it. This displaced air must have somewhere to go. This resistant force is known as induced drag. The phenomenon.
Airflow over the Bottom Surface. It is seeking to escape around the wing. Airflow over the Top Surface. The air flowing over the lower surface. Eddies and vortices are formed which tend to unite into one large eddy at each wing tip. When the two airflows unite at the trailing edge. Resistance caused by the effect of one part on another i.
It increases as the angle of attack increases and decreases as the angle of attack decreases. Gliders and sail planes are therefore commonly designed with high aspect ratio wings. A wing with a high aspect ratio. In order to support the weight of an airplane. Even the most carefully designed individual parts must.
Hence the lift of an airfoil can be expressed as a formula by: S And the drag by: Although induced drag cannot be eliminated. The lift and drag of an airfoil depend not only on the angle of attack. As has been stated. The shape of the air-foil The plan area of the airfoil or wing area.
Induced drag does not increase as the speed increases. The density of the air. Attached to the wing tip. The operational aspects of flight in areas where wing-tip vortices are present are discussed in the section Wake Turbulence in Chapter Airmanship.
On the contrary. The induced drag characteristics of a wing are not the same very near the ground as they are at altitude. They depend on the shape of the airfoil and will alter with changes in the angle of attack. See Ground Effect in Chapter Airmanship.
It has also been found that winglets are effective in reducing induced drag. Induced drag is. The lift-drag ratio is used to express the relation between lift and drag and is obtained by dividing the lift coefficient by the drag coefficient.
Hence drag is the price we pay for lift. It will be obvious that the heavier the airplane and the higher the span loading on the wing.
It is therefore necessary to find the best compromise. During landing and take-off. Lift and Drag Curves As the amount of lift varies with the angle of attack. This phenomenon is known as ground effect. The downgoing aileron. The effect of streamlining an object can be seen in Fig. A flat plate or a round ball moving through the air disturb the smooth flow of air and set up eddies behind them. The drag on the downgoing aileron is known as aileron drag and if not corrected for in the design of the aileron.
Effects of Streamlining. The curves in Fig. The C. The upgoing aileron. The values of CL. Streamlining In this age when everything from trains to children's toys is streamlined. Aileron Drag In banking to make an airplane turn. The general appearance of the co-ordinates in Fig. Frise Ailerons. Both frise and differential ailerons have been designed to overcome aileron drag.
On differential ailerons, the downgoing aileron moves through a smaller angle than the upgoing aileron. In frise ailerons, the nose of the upgoing aileron projects into the airflow, while the downgoing aileron is streamlined. The Boundary Layer The boundary layer is a very thin sheet of air lying over the surface of the wing and, for that matter, all other surfaces of the airplane. Because air has viscosity, this layer of air tends to adhere to the wing. As the wing moves forward through the air, the boundary layer at first flows smoothly over the streamlined shape of the airfoil.
Here the flow is called the laminar layer. Laminar and Turbulent Layer. As the boundary layer approaches the centre of the wing, it begins to lose speed due to skin friction and it becomes thicker and turbulent. Here it is called the turbulent layer.
The point at which the boundary layer changes from laminar to turbulent is called the transition point Fig. Where the boundary layer becomes turbulent, drag due to skin friction is relatively high. As speed increases, the transition point tends to move forward. As the angle of attack increases, the transition point also tends to move forward.
Various methods have been developed to control the boundary layer in order to reduce skin friction drag. Suction Method. One method uses a series of thin slots in the wing running out from the wing root towards the tip.
A vacuum sucks the air down through the slots, preventing the airflow from breaking away from the wing and forcing it to follow the curvature of the wing surface.
The air, which is sucked in, siphons through the ducts inside the wing and is exhausted backwards to provide extra thrust. The laminar flow airfoil is itself a structural design intended to make possible better boundary layer control. The transition point at which the laminar flow of air breaks down into turbulence is at or near the thickest part.
As can be seen in the accompanying illustration Fig. Vortex generators Fig. They are placed at an angle of attack and like a wing air-foil section generate vortices. These tend to prevent or delay the breakaway of the boundary layer by re-energizing it. They are lighter and simpler than the suction boundary layer control system described above.
COUPLES The principle of equilibrium has already been introduced at the beginning of this chapter in the discussion of the forces that act on an airplane in flight. When two forces, such as thrust and drag, are equal and opposite, but parallel rather than passing through the same point, they are said to form a couple.
A couple will cause a turning moment about a given axis as in Fig. If weight is ahead of lift, the couple created will turn the nose of the airplane down. Conversely, if lift is ahead of weight, the couple created will turn the nose of the airplane up.
Forces acting on an Airplane in Flight. It drag is above thrust, the couple formed will turn the nose of the airplane up. Conversely, if thrust is above drag, the couple formed will turn the nose of the airplane down. Notice that in Fig. Introduces various form of navigation from dead reckoning to from the ground up aviation reading to radio and GPS navigation. If you are attacked while unarmed, practicing this quick and simple gun disarming technique could save your life and the Se descubren y contagian Everyday low prices and free Early in the Stone Age, humans lived in small, nomadic groups.
During much of this period, the Earth was in Editorial Reviews. Language Notes. German in einem Antiquariat ein Buch, das ihn auf magische Weise anzieht: Mohammad Salemy. Can we identify photographic social