MOHAMED SATHAK AJ COLLEGE OF ENGINEERING CHENNAI DEPARTMENT OF AERONAUTICAL ENGINEERING
AE6413 - CAD & AIRCRAFT COMPONENT DRAWING LAB MANUAL
Signature of Lab-in-charge HOD
Signature of
AE6413 CAD AND AIRCRAFT COMPONENT DRAWING
LTPC0042
OBJECTIVES To introduce the concept of design of basic structural components and to draft both manually and using modelling package. LIST OF EXERCISES 1. Design and drafting of riveted joints 2. Design and drafting of welded joints. 3. Design and drafting control components cam. 4. Design and drafting control components bell crank. 5. Design and drafting control components gear. 6. Design and drafting control components push-pull rod. 7. Three view diagram of a typical aircraft. 8. Layout of typical wing structure. 9. Layout of typical fuselage structure. 10. Layout of control system. TOTAL : 60 PERIODS OUTCOMES Ability to design and draw different joints and components using manual drafting method.
DESIGN AND DRAFTING OF RIVETED JOINTS
Ex No: 1 Date: AIM:
To design the riveted joints by over lapping and butt joint method using AUTOCAD 2004 software.
THEORY OF RIVETED JOINTS: TYPE OF JOINTS: Riveted joints may be classified according to • Purpose for which it is used for Ex., structure (or) leak proof joints. • The method butt joints. •
of
placing
and
joining
members
as
lap
(or)
The type of rivet employed such as solid tabular (or) explosive rivets.
• The number of rows of rivet such as single, double, triple (or) quadratic riveted joints.
LAP JOINT: The places to be connected over lap each other and rivets pass through drilled holes. when the plates are tension (or) compression Fig(1),a couple acts about the rivets, being not in same plate tending to bend joints. To avoid the plates are sometimes bend before riveting to approximately infinite force shown, to reduce the bending action.
BUTT JOINT: The plates are kept in alignment and a butt strap (or) cover plate {either single or double} is plate over the joint and rivets are inserted through the hole in plates aligned over another. The connection of two main plates is through but straps. The butt joint with single butt strap has some fracture that of lap joints. Thus therefore should never be used for high loading and pressure feed areas which are fuselage, wings attachment are scalped that they be efficiently caused. Those joints are called single riveted, a double riveted etc, depending upon the no of rows of rivet on each main plate.
SINGLE COVERED BUTT JOINT:
DOUBLE COVERED BUTT JOINT:
TERMINOLOGY: 1. Gauge line: The line through the centers of rivet and parallel to edge of plate is termed as a row (or) gauge line.
2. Pitch: The distance between centers of adjacent rivet measured on gauge line called the pitch “p”.
3. Back pitch (or) Transverse pitch (Pb): The distance between the rivet centers in the adjacent gauge line in the some plate is called the back pitch (or) transverse pitch.
4. Diagonal pitch: The distance between the adjacent rivet centers to adjacent gauge line for zigzag riveting.
DESIGN CONSIDERATION OF RIVETED JOINTS:
1. Failure modes of riveted joints: A joint is said to have failed if plate gets separated from other. This separation can take place. All the rivets gets sheaved for lap joint and butt joint with single strap the rivets are in single shear while in butt joints with double strap, the rivets are in double shear shown figure.. A plate get torn along any section in this case all the rivets except these between the edge of torn plate and tearing section gets sheared. It is only by this combination that the plate small tear along a section.
2. All the rivets are crushed: The number of rivets failed shall change with the change in no of rows and no of rivets in a row. The basic relations derived below consider only one row of rivets and one pitch length of joint and these equations of rivet subjected to failure.
TERMINOLOGY RIVETED JOINTS:
Let σc=allowable crushing stress at the place or rivet σt=allowable tensile stress in place σs=allowable shear stress in place
3. Plate tearing in front of the rivet: This mode of failure is rarely encountered when the distance of the edge from the nearest row is very small generally the margin „M‟ is taken as 1.5d.
4. Tearing of the plate: The plate is the weaker between the rivet holes. •
Tearing area of the plate per pitch length=t[p-d]
•
Tearing resistance of plate per pitch length= σt[t(p-d)]
5. Shearing of rivets: Shearing area of rivet in single {lap joint} = d
2
Shearing area of rivet in double shear is not exactly double of that in single but little less. As per in Indian boiler regulations, it is taken as 1.875times the area in single shear. 2 According shear as of a rivet in double shear =d 1.875 Shearing area shall be different for lap and joints. Shearing resistance of rivet in double 2
shear =σsd Shearing resistance of rivet in double shear =1.875d
2
6. Crushing of rivets: Crushing area of a single rivet =d×t and if „n‟ be the no of rivets under crushing the crushing resistance is equal to σcr. The no of rivets in shear equal the no of rivet in crushing.
ALL RIVETS SHEARED:
P
P
7. Number of rivets in shear and crushing: If the joints has more than one row of rivets then following method a shall help in flinching out the no of rivet in shear in one pitch in of the joints. Draw the joints to be designed. Consider the pitch length of joints draw two parallel lines AB and CD at a distance „p‟ apart and passing through centers of adjacent rivets of a row.
The rivets in shear are equal to the no of rivets contained between these lines for Eg in fig. First row and second row has one rivet each in shear.Thus the rivets in shear are two. Description of joint like lap joint,butt joint with single strap (or) double strap determines 2 2 the shearing area per rivets (ie) d (or) 1.875d Total shearing area of rivets equal the produce the value determined at above.
8. Estimation of strength of riveted joints: For a given the rivets are so designed for failure to occur the strength of rivets in all the possible modes of failure should be equation form different type of failure discussed earlier following equation are obtained. 2
Equating shearing resistance to crushing resistance n* d (or)σs=n*dtpσcr and assuming σcr=σs ,it simplifies to •
d=2.54t ,for rivets in single shear
•
d=1.075t,for rivets in double shear.
Thus for d<2.54t crushing failure will not occurs in lap joints and butt joints with single strap and for d<1.075t rivets will never failure in crushing in any type of joints. Knowing t and d the pitch of rivet in found by equating the shearing resistance of rivet found be tearing resistance of one pitch length of joints.
9. Efficiency of riveted joints: Efficiency of riveted joints is the ratio of strength of a joint (in a particular mode of failure) to the tearing strength of imperforated plate. The various expressions are Tearing efficiency : ηt = tearing resistance of one pitch length of joint/tearing resistance one pitch length of imperforated plate is =σt(p-d)/ptσt
of
ALL RIVETS SHEARED: Tear along this line
Plates
Rivets
=p-(d/p) Shearing efficiency:ηs=shearing resistance of rivets per pitch length/tearing resistance of undrilled plate. Crushing efficiency:ηcr=crushing resistance of rivets or holes per pitch length of joint/tearing resistance of undrilled plate.
For Lap joints, •
single 45% to 65%
•
double 03% to 77%
•
triple 77% to 85%
Butt joints, •
single 60% to 80%
•
double 75% to 85%
•
triple 80% to 90%.
Command used:
Line
Circle
Offset
Hatch
Arc
PLATE TEARING IN FRONT OF THE RIVET:
P
P
TEARING OF RIVETS:
P
P
SINGLE SHEAR FOR LAP JOINT:
P P
DOUBLE SHEAR FOR BUTT JOINT:
P
P P
DRAFTING:
Ex No: 1
BUTT JOINT
Date:
ALL DIMENSION ARE IN MILLIMETERS
Ex No: 1
LAP JOINT
Date:
RESULT: Thus for riveted joints with over lapping and butt joints method has been designed with the consideration of failure which are being occurred in riveted joints and also has been drafted by using AUTOCAD 2004 software.
Ex No: 2
DESIGN AND DRAFTING OF WELDED JOINTS.
Date: AIM: To design the welded joints which are used for assembling aircraft structures by using AUTOCAD 2004 software.
WELDED JOINTS: Welded joints are threaded, cottered, or knuckle joints are permanent in nature and the component together cannot be separated or dissembled without breaking the weld metal to the connected part. A machine part or structure whose component parts are joint by welding is called weldment. Welded joints are light in weight, when compared to riveted joints due to elimination of corer plates or straps, gassed plates, chip angle
TYPES OF WELDED JOINTS: There are five basic forms of welded joints: 1. Butt weld 2. Lap weld 3. Edge weld 4. Corner weld 5. T-weld.
BUTT WELD: A butt weld is obtained by putting together the edges of two pieces having practically the same cross section and heating until fused together.
LAP WELD: The plates to be joined are made to overlap each other for a certain distance and the right angle recess so forward along the width of the plates are filled with weld metal.
EDGE WELD:
This type of joint is not recommended for plates thicker than 6mm.
TEE WELD: The plates to be joined to form a tee may be beveled at on one side, on both sides or is may not be beveled at all. Although, these joints should preferably be welded on both sides, this is not always possible as the two sides may not be accessible.
TEE WELD:
CORNER WELD:
If a fillet weld is placed on the inside of a corner joint, it is usually a light weld. The total throat „t‟ of the weld is of the order of 1.35 times the thickness of the plate.
DESIGN CONSIDERATIONS OF WELDED JOINT: Strength of welds in plane loading: Welded joints subjected to tension may be divided into three classes with respect to the internal Stress set up at the external load. IN CLASS 1, the weld is subjected only to longitudinal shear. IN CLASS 2, the weld is in transverse shear in tension. IN CLASS 3, the weld is in pure tension.
CLASS 1: LONGITUDINAL FILLET WELD: In this type, it should be noted that the shear area of weld resisting the external load. “p” 2tl, where l is the effective length of each weld and „t‟ is the throat thickness because failures are most often across the throat. σs = p/2tl 0 Since t=bcos45 , b is the size of the weld equal to plate thickness the shear stress is σs =p/1.44bl or o.707p/bl If the welds are long enough the load is not distributed uniformly, permissible loads should be thereafter reduced to about 80 to 90% of those for short welds. If case of the longitudinal of parallel fillet weld is subjected to variable loads, the effective of stress concentration at the ends of the weld must be considered. If the load‟p‟ in the case considered is a variable load the weld size would be worked out as follows Area resisting shear =2tl=1.414 bl If „σs‟ is the permissible shear stress intensity, then allowable load per unit length of weld=1.414 σs. Taking the effect of stress concentration in account allowable load per unit length of weld =1.414 σs /kt. Then required weld size b= p.kf/1.414zigma s. and if weld size is known and stress intensity in weld metal is required and it is given by. σs = p.kf/1.414, σs =0.707p.kf/bl
CLASS 2: TRANSVERSE FILLET WELD: In the case of class-2 weld the shear of the weld metal results in failure. It can be proved mathematically that the plane of max shear stress in the conventional 45 fillet weld, weld with both legs equal is the 45, throat when subjected to transverse load. This results in greater strength for transverse Fillet weld are taken to be of equal strength index static load considered. Area in shear for both welds=2tl Resisting strength=1.414 σs.bl, σs = p/1.414 bl. For variable load = σs =0.7071 p.kf/b
CLASS 3: BUTT WELD: The weld metal is subjected to tensile stresses for a flush weld, area resisting failure=bl. Resisting strength of weld metal=bl. σt = p. In variable load σt = p.kf/bl.
Command used:
Line
Circle
Offset
Hatch
Arc
DRAFTING: Ex No: 2
WELDED JOINTS
Date:
ALL DIMENSIONS ARE IN MILLIMETERS
RESULT: Thus for the welded joints are designed according to its different loading conditions and has been drafted by using AUTOCAD 2004 software.
Ex No: 3 DESIGN AND DRAFTING CONTROL COMPONENT CAM Date: AIM: To design and draft control component cam by using AUTOCAD 2004 software.
DESCRIPTION: CAM MECHANISMS: The transformation of one of the simple motions, such as rotation, into any other motions is often conveniently accomplished by means of a cam mechanism. A cam mechanism usually consists of two moving elements, the cam and the follower, mounted on fixed frame.cam devices are versatile, and almost any arbitrarily-specified motion can be obtained. In some instances, they offer the simplest and most compact way to transform motions. A cam may be defined as a machine element having a cured outline or a groove, which by its oscillation or rotation motion, gives a predetermined specified motion to another element called the follower. The cam has a very important function in the operation of many classes of machines, especially those of the automatic type, such as printing presses, textile machinery, gear-cutting machines, and screw machines. In any class of machinery in which automatic control and accurate timing are paramount, the cam is an indispensable part of variety. Some of the most common forms will be considered in this chapter.
CLASSIFICATION OF CAM MECHANISMS: We can classify cam mechanisms by the modes of input/output motion, the configuration and arrangement of the follower, and the shape of the cam. We can also classify cams by the different types of motion events of the follower and by means of a great variety of the motion characteristics of the cam profile.
CAM- NOMENCLATURE: TRACE POINT: A theoretical point on the follower, corresponding to the point of a fictitious knifeedge follower. It is used to generate the pitch curve. In this case of a roller follower, the trace point is at the center of the roller.
PITCH CURVE: The path generated by the trace point at the follower is rotated about a stationary cam.
WORKING CURVE: The working surface of a cam in contact with the follower. For the knife-edge follower of the plate cam, the pitch curve and the working curves coincide. In a close or grooved cam there is an inner profile and an outer working curve.
PITCH CIRCLE; A circle from the cam center through the pitch point. The pitch circle radius is used to calculate a cam of minimum size for a given pressure angle.
PRIME CIRCLE (REFERENCE CIRCLE): The smallest circle from the cam center through the pitch curve.
BASE CIRCLE: The smallest circle from the cam center through the cam profile curve.
STROKE : The greatest distance or angle through which the follower moves or rotates.
FOLLOWER DISPLACEMENT: The position of the follower from a specific zero or rest position (usually it‟s the position when the follower contact with the base circle of the cam) in relation to time or the rotary angle of the cam.
PRESSURE ANGLE: The angle at any point between the normal to the pitch curve and the instantaneous direction of the follower motion. This angle is important in cam design because it represents the steepness of the profile.
Command used:
Circle Offset Hatch Arc
DRAFTING: Ex No: 3
CONTROL COMPONENT CAM
Date:
ALL DIMENSIONS ARE IN MILLIMETERS
RESULT: Thus the control components of cam has been drafted by using AUTOCAD 2004 software.
DESIGN AND DRAFTING CONTROL COMPONENTS
Ex No: 4
BELLCRANK Date: AIM: To design and draft the control components of ell crank by using AUTOCAD 2004 software.
MECHANISMS OF BELL CRANK: A bell crank is a type of crank that changes motion through an angle. The angle can be 0 0 0 any angle from 0 to 360 , although 90 and 180 are common. A bell crank is shown fig 1. Bell crank are the most component in mechanical linkage. Bell cranks are simple devices that are used to change the direction of movement. In fig 1, the 0 input and output direction of movement differ by 90 . Bell crank can also create mechanical advantage when L1
L2.
Command used:
Line
Circle
Offset
Hatch
Arc
DRAFTING: Ex No: 4
BELL CRANK
Date:
ALL DIMENSION ARE IN MILLIMETERS
RESULT: Thus the control components of bell crank has been drafted by using AUTOCAD 2004 software.
Ex No: 5 DESIGN AND DRAFTING CONTROL COMPONENTS
GEAR Date: AIM: To design and draft the control components of gear by using AUTOCAD 2004 software.
DESCRIPTOPN: A gear or more correctly a "gear wheel" is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine. Geared devices can change the speed, magnitude, and direction of a power source. The most common situation is for a gear to mesh with another gear, however a gear can also mesh a non-rotating toothed part, called a rack, thereby producing translation instead of rotation. The gears in a transmission are analogous to the wheels in a pulley. An advantage of gears is that the teeth of a gear prevent slipping. When two gears of unequal number of teeth are combined a mechanical advantage is produced, with both the rotational speeds and the torques of the two gears differing in a simple relationship.
TYPES OF GEAR: o o o o o o o o o o o o o o
External vs. internal gears Spur Helical Double helical Bevel Hypoid Crown Worm Non-circular Rack and pinion Epicyclic Sun and planet Harmonic drive Cage gear
SPUR GEAR: Spur gears or straight-cut gears are the simplest type of gear. They consist of a cylinder or disk with the teeth projecting radially, and although they are not straight-sided in form, the edge of each tooth is straight and aligned parallel to the axis of rotation. These gears can be meshed together correctly only if they are fitted to parallel shafts.
HELICAL GEAR: Helical gears offer a refinement over spur gears. The leading edges of the teeth are not parallel to the axis of rotation, but are set at an angle. Since the gear is curved, this angling causes the tooth shape to be a segment of a helix. Helical gears can be meshed in a parallel or crossed orientations. The former refers to when the shafts are parallel to each other; this is the most common orientation. In the latter, the shafts are non-parallel, and in this configuration are sometimes known as "skew gears".
DOUBLE HELICAL: Double helical gears, or herringbone gear, overcome the problem of axial thrust presented by "single" helical gears by having two sets of teeth that are set in a V shape. Each gear in a double helical gear can be thought of as two standard mirror image helical gears stacked. This cancels out the thrust since each half of the gear thrusts in the opposite direction. Double helical gears are more difficult to manufacture due to their more complicated shape. For each possible direction of rotation, there are two possible arrangements of two oppositely-oriented helical gears or gear faces. In one possible orientation, the helical gear faces are oriented so that the axial force generated by each is in the axial direction away from the center of the gear; this arrangement is unstable. In the second possible orientation, which is stable, the helical gear faces are oriented so that each axial force is toward the mid-line of the gear. In both arrangements, when the gears are aligned correctly, the total (or net) axial force on each gear is zero. If the gears become misaligned in the axial direction, the unstable arrangement generates a net force for disassembly of the gear train, while the stable arrangement generates a net corrective force. If the direction of rotation is reversed, the direction of the axial thrusts is reversed, a stable configuration becomes unstable, and vice versa. Stable double helical gears can be directly interchanged with spur gears without any need for different bearings.
BEVEL GEAR: A bevel gear is shaped like a right circular cone with most of its tip cut off. When two bevel gears mesh their imaginary vertices must occupy the same point. Their shaft axes also intersect at this point, forming an arbitrary non-straight angle between the shafts. The angle between the shafts can be anything except zero or 180 degrees. Bevel gears with equal numbers of teeth and shaft axes at 90 degrees are called miter gears.
The teeth of a bevel gear may be straight-cut as with spur gears, or they may be cut in a variety of other shapes. Spiral bevel gear teeth are curved along the tooth's length and set at an angle, analogously to the way helical gear teeth are set at an angle compared to spur gear teeth. Zero bevel gears have teeth which are curved along their length, but not angled. Spiral bevel gears have the same advantages and disadvantages relative to their straight-cut cousins as helical gears do to spur gears. Straight bevel gears are generally used only at speeds below 5 m/s (1000 ft/min), or, for small gears, 1000 rpm.
HYPOID GEAR: Hypoid gears resemble spiral bevel gears except the shaft axes do not intersect. The pitch surfaces appear conical but, to compensate for the offset shaft, are in fact hyperboloids of revolution. Hypoid gears are almost always designed to operate with shafts at 90 degrees. Depending on which side the shaft is offset to, relative to the angling of the teeth, contact between hypoid gear teeth may be even smoother and more gradual than with spiral bevel gear teeth. Also, the pinion can be designed with fewer teeth than a spiral bevel pinion, with the result that gear ratios of 60:1 and higher are feasible using a single set of hypoid gear. This style of gear is most commonly found driving mechanical differentials; which are normally straight cut bevel gears; in motor vehicle axles.
Command used:
Line
Circle
Offset
Hatch
Arc
DRAFTING: Ex No: 5
GEAR ASSEMBLY
Date:
ALL DIMENSION ARE IN MILLIMETERS
RESULT:
Thus the control component of gear has been drafted by using AUTOCAD 2004 software.
Ex No: 6
DESIGN AND DRAFTING CONTROL COMPONENTS PUSH PULL ROD
Date: AIM: To design and draft the control component of push pull rod by using AUTOCAD 2004 software.
DESCRIPTION: The push pull rod is used between bell crank and from bell crank to torque arms (“horns”) to transmit the force and motion from one to the other. A push-pull rod connected to a bell crank is shown in fig. push pull rods are also called control rods because they are often in control systems.
APPLICATION: AIRCRAFT: The push-pull rod is used to move the control surface of the Aircraft.
IC ENGINE: The push pull rod is used to operate the inlet and outlet port of the IC engines.
Command used:
Line
Circle
Offset
Hatch
Arc
DRAFTING: Ex No: 6
PUSH PULL ROD
Date:
ALL DIMENSION ARE IN MILLIMETERS
RESULT: Thus the control components of push pull rod has been drafted by using AUTOCAD 2004 software.
Ex No: 7
THREE VIEW DIAGRAM OF TYPICAL AIRCRAFT
Date: AIM: To design and draft the three view diagram of typical aircraft by using AUTOCAD 2004.
CATEGORIES OF AIRCRAFT: Supported by lighter-than-air gases (aerostats) Unpowered Balloon
Powered Airship
Supported by LTA gases + aerodynamic lift Unpowered Hybrid moored balloon
Powered Hybrid airship
Supported by aerodynamic lift (aerodynes) Unpowered fixed-wing Glider hang gliders Paraglider Kite
Powered fixed-wing Powered airplane (aeroplane) powered hang gliders Powered paraglider Flettner airplane Ground-effect vehicle Powered hybrid fixed/rotary wing Tilt wing Tilt rotor Coleopter
Unpowered rotary-wing Rotor kite
Other means of lift
Powered rotary-wing Autogyro Gyrodyne ("Heliplane") Helicopter Powered aircraft driven by flapping Ornithopter
Powered Hovercraft Flying Bedstead Avrocar
WHAT IS AN AIRCRAFT: Aircraft are vehicles which are able to fly by being supported by the air, or in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.
MILITARY AIRCRAFT: A military aircraft is any fixed-wing or rotary-wing aircraft that is operated by a legal or insurrectionary armed service of any type. Military aircraft can be either combat or non-combat:
Combat aircraft are aircraft designed to destroy enemy equipment using its own armament. Non-Combat aircraft are aircraft not designed for combat as their primary function, but may carry weapons for self-defense. Mainly operating in support roles.
Combat aircraft divide broadly into fighters and bombers, with several in-between types such as fighter-bombers and ground-attack aircraft (including attack helicopters). Other supporting roles are carried out by specialist patrol, search and rescue, reconnaissance, observation, transport, training and Tanker aircraft among others.
CIVIL: Civil aircraft divide into commercial and general types, however there are some overlaps.
COMMERCIAL: Commercial aircraft include types designed for scheduled and charter airline flights, carrying both passengers and cargo. The larger passenger-carrying types are often referred to as airliners, the largest of which are wide-body aircraft. Some of the smaller types are also used in general aviation, and some of the larger types are used as VIP aircraft.
GENERAL AVIATION: General aviation is a catch-all covering other kinds of private and commercial use, and involving a wide range of aircraft types such as business jets (bizjets), trainers, homebuilt, aerobatic types, racers, gliders, war birds, firefighters, medical transports, and cargo transports, to name a few. The vast majority of aircraft today are general aviation types. Within general aviation, there is a further distinction between private aviation (where the pilot is not paid for time or expenses) and commercial aviation (where the pilot is paid by a client or employer). The aircraft used in private aviation are usually light passenger, business, or recreational types, and are usually owned or rented by the pilot. The same types may also be used for a wide range of commercial tasks, such as flight training, pipeline surveying, passenger and freight transport, policing, crop dusting, and medical evacuations. However the larger, more complex aircraft are more likely to be found in the commercial sector. For example, piston-powered propeller aircraft (single-engine or twin-engine) are common for both private and commercial general aviation, but for aircraft such as turboprops like the Beech craft King Air and helicopters like the Bell Jet Ranger, there are fewer private owners than commercial owners. Conventional business jets are most often flown by paid pilots, whereas the new generations of smaller jets are being produced for private pilots.
Command used:
Line
Circle
Offset
Hatch
Arc
DRAFTING:
Ex No: 7 Date:
TOP VIEW
FRONT VIEW
THREE VIEW DIAGRAM
SIDE VIEW
RESULT:
Thus the three view diagram of a typical aircraft has been drafted by using AUTOCAD 2004 software
Ex No:8
LAYOUT OF TYPICAL WING STRUCTURE
Date: AIM: To draft and study the wing structural layout of a specified aircraft by using AUTOCAD 2004 software.
WING: The primary lifting surface of an aircraft is the wing. Wing are attached to airplanes in a location vertically and longitudinally
BASIC FEATURES OF WING CONSTRUCTION: Conventional wing are three general types: mono spar, two spar, multi spar. True stressed skin. Wing may have shear weds but no true spars.
WING SPAR: It is sometimes called a wing beam, is a principal span wise member of a wing structure
WING RIB: It is sometimes called a plain rib, is a chord wise member of the wing structure used to give the wing section is shape and also to transmit the air loads from the covering the spar.
STIFFENERS (OR) STRINGERS: To assist holding the shape of the wing span wise called stiffness (or) stringers is attached to the skin. For wooden wing construction, the wing spars must be made of a/c quality solid wood and plywood. Wood spars may be solid or may be build up
STRESSED SKIN METAL CONSTRUCTION: The skin of the wing is riveted to the ribs and stringers are serves not only as a covering but also a part of the basic structure of the wing. Most a/c use aluminum as wing covering. The aluminum skin has high strength and is employed as a primary load carrying member. The skin is quite string in tension and shear and if stiffened by other members may be made to carry some compressive load.
TYPICAL WING LOCKHEAD:
STRUCTURE
OF
TRANSPORT
AIRCRAFT
The mainframe of a modern transport wing consists of spars, ribs, bulkheads and skin panels with span ark stiffening members. The assembly of the structures may include the use of non-metallic composite components and bonding of metal structures as well as the use of conventional metal alloy and fasteners. The structural strength of wing must be sufficient to carry its own weight along with weight of fuel in its wings and force imposed by the flight controls and landing gears. These stresses vary tremendously in magnitude during a/c transition from moving on ground to force flight operation s to returning to the ground. The basic structure of a modern transport wing is shown. Transport wing consists of two or more main spars with intermediate spars assist the main spars in carrying operational loads. The front and rear spars provide main supporting structure for fittings attaching fuselage engine, pylons, main landing gear and flight surface to wing. Located between the ribs, depending upon their design may be used for purposes such as fuel bulkheads and support of control surfaces as well as providing the aerofoil shape of the wing.
Command used:
Line
Circle
Offset
Hatch
Arc
DRAFTING: Ex No:8 Date:
RESULT:
LAYOUT OF TYPICAL WING STRUCTURE
Thus the layout of typical wing structure has been drafted by using AUTOCAD 2004 software.
Ex No:9
LAYOUT OF TYPICAL FUSELAGE STRUCTURE
Date: AIM: To draft and study the fuselage structure layout of specialized aircraft by AUTOCAD 2004 software.
using
FUSELAGE: The fuselage is the body of aircraft to which the wings and the tail unit are attached. It provides space for the crew, passenger, cargo ,control and other items, depending upon it size and design of the aircraft. The aircraft structure is designed to provide maximum strength and minimum weight. In general, fuselage are classified into three types depending upon the method, to which the stress are transmitted to the structure. The three types according to this classified are truss, semimonocoque, monocoque.
CONSTRUCTION OF FUSELAGE: The fuselage are designed with a variety of structural components. The great majority of fuselage are all metal and semi monocoque in construction. This statement applies to small medium and large aircraft. The interior structure to which the skim or plating is attached consists of longerons, frames, bulkheads, stringer, gussets, and possible internal coastal members, riveted bound or jointed together form a rigid structure that shapes of fuselage. The skim or plating is riveted or bonded to the structure to form the complete unit. Fuselage for aircraft are designed with many similarities. The forward section of the fuselage usually contain the cockpit and passenger cabin. The shape of this section depends upon the passenger capacity and the performance specification for the aircraft. The real section of the tail cone is usually circular or rectangular in cross – section and taper towards the tail.
TYPICAL FUSELAGE STRUCTURE OF TRANSPORT AIRCRAFT LOCKHEAD L-1101: Fuselage for transport aircraft generally include a section forward of the main cabin to provide a streamlined nose, a main cabin section, which is almost uniformly cylindrical in shape and tail section. Which tapes to minimum size at the extreme real and the material most commonly used throughout the structure are high strength fiber glass, graphite, Kevlar on secondary areas of structure and of many control surfaces.
FRAMES: These are circumferential members gradually spaced at regular intervals along the length of fuselage. Frames can stabilize the skin and stringers can distribute the concentrated loads.
BULKHEADS: Heavy frames reinforced by beams attached to webs are usually called bulkheads.
STRINGERS; These are longitudinal members spaced around the fuselage circumference the extend the full length of fuselage. The stringers attached to the out board edge of frame and the in board face of skin.
FLOOR BEAMS: It provides the support for the cabin floor attack to the frame and skin horizontally across the fuselage.
KEEL BEAMS: It is a major longitudinal fuselage component in the wing center section and wheel well area. It extends along the fuselage center line through the wheel well and under the wing center section. The transport fuselage contains one or more mid section assemblies. These mid section assemblies one basically circular in shape with a constant cross size. The mid section of the structure contains landing gear attached points. The off section changes the cross sectional shape of the fuselage into the size and shape necessary to join with fuselage at the body or tail cone. The center body or tail cone is in the point of attachment for the flight control surface and depending on the aircraft design. The fuselage sections are joined to complete the basic assembly of the fuselage may also in corporate an engine installation area.
Command used:
Line
Circle
Offset
Hatch
Arc
DRAFTING: Ex No: 9
LAYOUT OF TYPICAL FUSELAGE STRUCTURE
Data:
LD-2
LD-2
Boeing 767
LD-3
LD-3
Boeing 747
LD-3
LD-3
Airbus A300
LD-3
LD-3
McDonell Douglas DC-10
LD-3
LD-3
Boeing 777
LD-3
LD-3
Boeing 747
CROSS SECTION OF FUSELAGE
FUSELAGE SHELL
LONGERONS
RESULT: Thus the layout of the typical fuselage structure has been drafted by using AUTOCAD 2004 software.
Ex No: 10
LAYOUT OF CONTROL SYSTEM
Date: AIM: To draft and study the control system layout of specialized aircraft by using AUTOCAD 2004 software.
TYPICAL CONTROLSYSTEMFOR A LARGEAIRCRAFT-BOEING: The primary flight controls are the aileron, elevators and rudders flight controls are powered from the three airplane hydraulic systems. There is no manual backup system when hydraulic power is lost. Spoilers assist the ailerons in providing roll airfoil and operate as speed brakes. The variable pitch horizontal stabilized assist the elevator is providing pitch control high lift for takeoff and landing is provided by trailing edge flaps and leading edge slats.
RUDDER CONTROL SYSTEM YAW CONTROL: Directional control about the yaw axis is provided by the rudder control system. The rudder is hydraulically powered and control through displacement of either pilots rudder pedals. Two yaws dampers operate through the rudder control systems to improve direction stability and help to eliminate unwanted yawing of the aircraft. Displacement of either nor of rudder pedals send a signal to the three rudder hydraulic actuators. The position of the rudder is shown on the EICA‟s {Engine Indicating and new alerting system } status display Rudder trim is available by rotating the rudder trim control to the desired direction. The control provides signals to the electric motor that reposition the rudder neutral point. The rudder trim indicator show the unit of rudder trim that are signaled. The control systems from the rudder pedals and trim control to the rudder actuator are modified by a rudder ratio changer. As airspeed increases the ratio reduces the rudder deflection that results from the rudders input The ratio changer receives air data computers airspeed input and provides control signals to an actuator powered by the left hydraulic system. The actuator modifies the pilots control input
RUDDER CONROL SYSTEM – YAW CONTROL:
YAW DAMPER
M
L
R
C
AILERON CONROL SYSTEM –ROLL CONTROL:
TRIM SWITCHES RIGHT
LEFT
M
C
ELEVATER CONTROL SYSTEM PITCH CONTROL: The pitch control surfaces consists of two hydraulically powered elevators and a hydraulically powered elevators and a hydraulically powered stabilizer to improve speed stability Moving either control column sends a signal to the hydraulic actuators on the elevators. There are three actuators for each elevator. If one control column should i am applying sufficient forward (or) after force to other causes two columns to disconnect pitch column is then available using the free control system. Elevator positions are shown on the EICA‟s status display. Separate pointers indicates the left and right elevator deflection two elevator, “feet system” provide artificial feet forces to the pilot‟s control columns
AILERON CONTROL SYSTEM ROLL CONTROL: The roll control surfaces consists of hydraulically powered ailerons and spoilers which are connected so that it one control wheel jams, applying additional forces causes the control wheels to disconnect roll control wheel. The aileron is located on each wing, rotating either control wheel sends a signed to the aileron hydraulically actuators. Two actuators are used for each aileron. It positioned are shown on the switches operate an electric motors that provides systems to reposition the aileron‟s hydraulic system is necessary to accurately set the aileron trim an aileron trim indicator is located on both control columns and indicates in unit of trim.
Command used:
Line
Circle
Offset
Hatch
Arc
ELEVATOR
CONTROL
SYSTEM
–
PITCH
CONTROL:
COLOUMN DISCONNECT
ELEVATOR FEED LEFT HYDRAULI C PROCESS
ELEVATOR FEED
RIGHT HYDRAULIC PROCESS
DRAFTING: Ex No: 10
FLEXIBLE CONTROL SYSTEM LAYOUT
Date:
CONTROL WHEEL BALANCING CABLE
CHAIN & SPROCKET(AILERON) CHAIN & SPROCKET(ELEVATOR)
PUSH ROD
ALL DIMENSIONS ARE IN MILLIMETERS
RESULT:
Thus the control system layout of specialized aircraft was drafted and studied by using AUTOCAD 2004 software.
