AMT 112 Aircraft Structure - Preliminary Module PDF

JOCSON COLLEGE AMT 112: AIRCRAFT STRUCTURES DEXTER T. YUSI, AMT, FA, MENM, PAF RSRV LICENSE NO: 146859 – A&P “Pursuit of Excellence”  JOCSON COLLEGE COURSE OVERVIEW I. COURSE CODE: AMT 112 II...

JOCSON COLLEGE AMT 112: AIRCRAFT STRUCTURES DEXTER T. YUSI, AMT, FA, MENM, PAF RSRV LICENSE NO: 146859 – A&P “Pursuit of Excellence”  JOCSON COLLEGE COURSE OVERVIEW I. COURSE CODE: AMT 112 II. COURSE TITLE: AIRCRAFT STRUCTURES III. COURSE CREDIT: 4 UNITS (3 HOURS LECTURE/WEEK; 3 HOURS LABORATORY/WEEK) 120 HOURS/SEMESTER IV. PRE-REQUISITE: None V. INSTRUCTOR’S NAME: DEXTER T. YUSI, MENM 1. PHONE NUMBER: 0955-961-7158 2. EMAIL ADDRESS: [email protected] 3. CONSULTATION HOURS: Tues 3:00PM-4:00PM “Pursuit of Excellence”  JOCSON COLLEGE COURSE OVERVIEW VI. COURSE DESCRIPTION: This course covers the basic knowledge in aircraft structures. It includes structural stresses imposed to aircraft in flight, components, and operations. The basic knowledge of flight controls surfaces & functions; primary flight control surfaces, secondary flight control surfaces, aileron reversal, unusual control, airbrakes, lift dampers, tabs, functions, inspection, repair of control cables, control balancing, inspection & repair of control cables & terminals. Rigging of fixed and rotary aircraft, check alignment of structures, assemble aircraft flight control surfaces. Perform airframe conformity and airworthiness inspections “Pursuit of Excellence”  JOCSON COLLEGE COURSE OVERVIEW VII. COURSE OBJECTIVES: At the end of the semester, the students can able to: 1. Identify defects, service and repair of wood structures. 2. Rig and check alignment of fixed and rotary aircrafts. 3. Assemble aircraft components, including flight control surfaces. 4. Jack, balance, rig and inspect moveable primary and secondary flight control surface. 5. Perform airframe conformity and airworthiness inspections. “Pursuit of Excellence”  JOCSON COLLEGE COURSE OVERVIEW VIII. COURSE CONTENT: PRELIM A Brief History of Aircraft Structures Major Structural Stresses Fixed Wing Aircraft FINALS Maintaining the Aircraft Rotary-Wing Aircraft Assembly and Rigging Helicopter Structures Rotorcraft Controls Airplane Assembly and Rigging MID-TERM Aircraft Rigging Stability and Control Aircraft Inspection Primary Flight Controls Trim Controls Auxiliary Lift Devices Control Systems for Large Aircraft “Pursuit of Excellence”  JOCSON COLLEGE COURSE OVERVIEW IX. GRADING SYSTEM: CLASS PERFORMANCE 60% ATTENDANCE 20% QUIZZES 20% RECITATION 20% ACTIVITY/ASSIGNMENT 20% ATTITUDE 20% MAJOR EXAM 40% TOTAL: =100% “Pursuit of Excellence”  JOCSON COLLEGE COURSE OVERVIEW X. COURSE / CLASS POLICIES: A. Student Conduct and Discipline: Attendance and Discipline. Students behind schedule for 15 minutes shall be considered late while students behind schedule for 30 minutes shall be considered absent. B. Examination /Quizzes: Examinations, either oral or written must be taken on the schedule announced at least one meeting before the examination day. Special Quizzes shall be given, provided a valid reason together with an excuse letter signed by the guardian / parent with corresponding attachments has been submitted. C. Course Requirement Submission: Late requirements shall be accepted but with less rating as compared to those requirements passed on schedule. D. Class Participation: Everyone is encouraged to participate in classroom discussions, activities, quizzes, recitation and laboratory activities. “Pursuit of Excellence”  JOCSON COLLEGE COURSE OVERVIEW XI. COURSE REQUIREMENTS Research work/assignment, quizzes, recitation, actual participation of the students, field trip & seminar (optional), examination (written/oral). - Cattleya Lecture Note (Every Major Exam Submmision) - Long Folder (For Activity/Assignment Compliance (Filler)) - Course Project XII. REFERENCES: 1.FAA Airframe Handbook Series 2018 2.Jeppesen Airframe Handbook “Pursuit of Excellence”  JOCSON COLLEGE ASSIGNMENT #1 Research the Following Terms: 1. What is an Aircraft? 2. Airframe & Powerplant 3. History of Aircraft Structural Designs 4. Development of Structural Designs 5. Monocoque, Semi-Monocoque & Combination – Structure -Written on a yellow paper / Printed Document (Long) w/ pictures, cite your references. To be submitted next meeting. “Pursuit of Excellence”  JOCSON COLLEGE WHAT IS AN AIRCRAFT? “Pursuit of Excellence”  JOCSON COLLEGE AIRCRAFT An aircraft (pl: aircraft) is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or the dynamic lift of an airfoil, or, in a few cases, direct downward thrust from its engines. Common examples of aircraft include airplanes, helicopters, airships (including blimps), gliders, paramotors, and hot air balloons. “Pursuit of Excellence”  JOCSON COLLEGE AIRCRAFT “Pursuit of Excellence”  JOCSON COLLEGE AIRCRAFT DESIGN & CONSTRUCTION Manufacturers improved aircraft durability and safety. Aircraft technician's responsibility to maintain the structural integrity. “Pursuit of Excellence”  JOCSON COLLEGE HISTORY OF AIRCRAFT STRUCTURAL DESIGNS Flying with wings made of feathers and wax Machines resembling birds Flapping wings by Leonardo da Vinci “Pursuit of Excellence”  JOCSON COLLEGE HISTORY OF AIRCRAFT STRUCTURAL DESIGNS Gliders of Lilienthal and Chanute– manned flight was possible By using the results of their experiments, WRIGHT BROTHERS developed a biplane glider “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE HISTORY OF AIRCRAFT STRUCTURAL DESIGNS Wings ribs are made from wood, covered with organic fabrics such as cotton or linen to form the lifting surfaces. Body frameworks made from bamboo or strips of wood and held together with piano wire. “Pursuit of Excellence”  HISTORY OF AIRCRAFT JOCSON COLLEGE STRUCTURAL DESIGNS Were built with a TRUSS STRUCTURE that used struts and wire-braced wings. “Pursuit of Excellence”  JOCSON COLLEGE HISTORY OF AIRCRAFT STRUCTURAL DESIGNS The occupants sat in open cockpits within a fabric-covered hull, or fuselage. “Pursuit of Excellence”  DEVELOPMENT OF JOCSON COLLEGE STRUCTURAL DESIGNS WORLD WAR 1 – AIRCRAFTS Engine installed up front and auxiliary surfaces mounted aft of the wings to form the tail, or empennage, of the airplane. “Pursuit of Excellence”  DEVELOPMENT OF JOCSON COLLEGE STRUCTURAL DESIGNS WORLD WAR 1 – AIRCRAFTS Increased knowledge of flight and the experience gained in building strong, lightweight structures Problem of decreasing the air resistance of their machines. Designers constructed a superstructure of wooden formers and stringers over the framework to produce a more streamlined shape. “Pursuit of Excellence” MAJOR COMPONENTS JOCSON COLLEGE OF AN AIRCRAFT “Pursuit of Excellence”  MAJOR COMPONENTS JOCSON COLLEGE OF AN AIRCRAFT The main sections of an airplane include the fuselage, wings, cockpit, engine, propeller, tail assembly, and landing gear. Understanding the basic functions of how these parts interact is the first step to understanding the principles of aerodynamics. “Pursuit of Excellence”  DEVELOPMENT OF JOCSON COLLEGE STRUCTURAL DESIGNS Formers provide the contoured cross- sectional shape to a structure. Stringers run the length between the formers to fill in the shape. “Pursuit of Excellence”  DEVELOPMENT OF JOCSON COLLEGE STRUCTURAL DESIGNS Structural designs was made in the latter years of World War I, when thin-walled steel tubing was welded together to form the fuselage truss. The structure reduced the overall weight of AIRCRAFT will increasing the structural strength. “Pursuit of Excellence”  MONOCOQUE JOCSON COLLEGE STRUCTURE The next advance in structural designs came with the development of a construction technique that allowed the aircraft to be formed without a truss frame. generally known as a stressed-skin structure “Pursuit of Excellence”  MONOCOQUE JOCSON COLLEGE STRUCTURE Aircraft to be built with a more streamlined shape and provided further reductions in weight because the skin itself carried the structural loads. Referred to as having a monocoque design. “Pursuit of Excellence”  MONOCOQUE JOCSON COLLEGE STRUCTURE Strips of spruce wood were glued together then cured under heat and pressure in a large concrete mold to form for the skin. Thin aluminum-alloy sheets were next used for the exterior of monocoque structures. “Pursuit of Excellence”  MONOCOQUE JOCSON COLLEGE STRUCTURE A disadvantage of monocoque designs is that they can fail once subjected to relatively minor dents. To further increase the strength of the structure, manufacturers improved their designs by developing semi- monocoque construction techniques. “Pursuit of Excellence”  MONOCOQUE JOCSON COLLEGE STRUCTURE The skin is fastened to a sub-structure or skeletal framework, which allows the loads to be distributed between the structural components and the skin of the aircraft. “Pursuit of Excellence”  JOCSON COLLEGE COMBINATION WITH IMPROVEMENTS IN AIRFRAME STRUCTURAL DESIGNS Aircraft powerplant performance and dependability also increased. As aircraft became capable of flying at high altitude, a means of pressurizing the cabin and cockpit area became necessary to increase the safety and comfort of the passengers and crew. “Pursuit of Excellence”  JOCSON COLLEGE AIRFRAME TECHNICIAN An airframe rating is authorized to work on all types of aircraft ranging from lighter-than-air equipment such as balloons and dirigibles, to rotorcraft and fixed wing airplanes. “Pursuit of Excellence”  JOCSON COLLEGE AIRFOIL SECTIONS The lift producing surfaces of an aircraft, such as the wings of an airplane or the rotor of a helicopter, have an aerodynamically efficient shape called an airfoil. “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE AIRFOIL SECTIONS An airfoil provides the lifting force when it interacts with a moving stream of air. As an airfoil moves through the air, it alters the air pressure around its surface. “Pursuit of Excellence”  AIRFOIL SECTIONS JOCSON COLLEGE A typical subsonic airfoil has a rounded nose, or leading edge, and a smooth taper into a relatively sharp point at the rear or trailing edge. “Pursuit of Excellence”  AIRFOIL SECTIONS JOCSON COLLEGE A typical subsonic airfoil has a rounded nose, or leading edge, and a smooth taper into a relatively sharp point at the rear or trailing edge. Most helicopter rotors and many high- speed airplanes use airfoil sections that are symmetrical; that is, the curvature on the top of the airfoil is the same as that on the bottom. “Pursuit of Excellence” AIRFOIL SECTIONS JOCSON COLLEGE “Pursuit of Excellence” AIRFOIL SECTIONS JOCSON COLLEGE “Pursuit of Excellence”  AIRFOIL SECTIONS JOCSON COLLEGE The movement of the air stream around the airfoil causes changes in the surrounding air pressure distribution to create lift. “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  AIRFOIL SECTIONS JOCSON COLLEGE If the airspeed is doubled, the amount of lift produced will increase four times. On the other hand, if the area of the airfoil is doubled, the amount of lift will also double. “Pursuit of Excellence”  AIRFOIL SECTIONS JOCSON COLLEGE Since at slow speeds the amount of lift may not be sufficient to support the aircraft. Airplanes usually have a method of changing the shape of the airfoil to increase the camber shape and/or wing area. This is done with leading or trailing edge devices such as flaps or slats “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence” AIRFOIL SECTIONS JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  AIRFOIL SECTIONS JOCSON COLLEGE A truss-type wing used on many slow- speed airplanes has its leading edge covered with thin sheet metal. Ribs are spaced at intervals throughout the wing structure and form the shape of the leading edge, camber, and trailing edge. “Pursuit of Excellence”  AIRFOIL SECTIONS JOCSON COLLEGE Each rib is also attached to the wing spar, which runs the length of the wing from the root to the tip. The spar is the main spanwise member of the wing structure and carries the aerodynamic loads to the fuselage structure. “Pursuit of Excellence”  AIRFOIL SECTIONS JOCSON COLLEGE All-metal general aviation airplanes, which have a relatively high speed, have the wing skin attached to the ribs and spars with flush rivets along the leading edge and back to about one-third of the upper camber. “Pursuit of Excellence” AIRFOIL SECTIONS JOCSON COLLEGE “Pursuit of Excellence”  TRANSMITTING LIFT JOCSON COLLEGE INTO THE STRUCTURE Lift must be transmitted into the structure in such a manner that the airplane can be balanced in every condition of flight. In addition, the structure must be built to support all of the loads without any damaging distortion. “Pursuit of Excellence”  TRANSMITTING LIFT JOCSON COLLEGE INTO THE STRUCTURE To do this, wings are mounted on an airplane in a location that places its center of lift just slightly behind the center of gravity. The center of lift is the point at which the air pressures produced by the wing can be considered concentrated. “Pursuit of Excellence”  TRANSMITTING LIFT JOCSON COLLEGE INTO THE STRUCTURE As an airplane is maneuvered and the angle of attack changes, the center of lift also changes and produces some rather large torsional loads on the wing structure. “Pursuit of Excellence”  TRANSMITTING LIFT JOCSON COLLEGE INTO THE STRUCTURE In addition to the twisting loads imposed on the structure, the wing is also subjected to bending loads. “Pursuit of Excellence”  TRANSMITTING LIFT JOCSON COLLEGE INTO THE STRUCTURE “Pursuit of Excellence”  TRANSMITTING LIFT JOCSON COLLEGE INTO THE STRUCTURE While weight is essentially concentrated at the fuselage, lift is produced along the full length of the wing. With the generation of lift, the wing tends to bend upward from the root toward the tip. The wing spars are designed to flex to carry these bending loads. “Pursuit of Excellence”  TRANSMITTING LIFT JOCSON COLLEGE INTO THE STRUCTURE As with other wing designs, spars are the main load-carrying members in a wing truss. In the past, spars were mainly manufactured of wood, but the majority of modern aircraft incorporate spars fabricated from extruded aluminum alloy. “Pursuit of Excellence”  JOCSON COLLEGE WOOD SPARS Usually made of Sitka spruce and may be either solid or laminated. Because of the difficulty in finding a single piece of near-perfect wood in the size needed for wing spars, many manufacturers produce laminated spars. “Pursuit of Excellence”  LAMINATED SPARS JOCSON COLLEGE Spar (aeronautics) - Wikipedia strips of wood that are glued together with the grain running in a parallel direction. As strong as a solid spar as long as it is manufactured from the same quality wood as a solid spar and manufactured to aviation standards. “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE COMPRESSION RIBS The spars are separated by compression members or compression struts, that may be either steel tubing or heavy-wall aluminum alloy tubing. Strengthened to take compressive loads. “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE DRAG WIRES The wires that extend from the front spar to the rear spar Running diagonally from inboard to outboard oppose the forces that tend to drag against the wing and pull it backward. “Pursuit of Excellence”  JOCSON COLLEGE ANTI-DRAG WIRES Run between the front and rear spar and run diagonally from outboard to inboard “Pursuit of Excellence”  JOCSON COLLEGE TRUSS TYPE WINGS A wing truss consisting of spars, compression members, and drag and anti-drag wires, Provides the lightweight and strong foundation needed for fabric-covered wings. “Pursuit of Excellence”  JOCSON COLLEGE NOSE RIBS To prevent air loads from distorting the leading edge, most wings have nose ribs. Nose ribs, sometimes called false ribs, extend from the front spar forward and are placed between each of the full-length former ribs. “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE STRESSED-SKIN WING CONSTRUCTION In the same manner as the fuselage, wings generally evolved from the truss form of construction to one in which the outer skin carries the greatest amount of the stresses. Semi-monocoque construction is generally used for the main portion of the wing, while the simple monocoque form is often used for control surfaces. “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE STRESSED-SKIN WING CONSTRUCTION One of the advantages of an all- metal wing is that it is designed to carry all of the flight loads within the structure It does not need any external struts or braces. Internally braced wings not requiring external support are called cantilever wings. “Pursuit of Excellence”  JOCSON COLLEGE DID YOU KNOW? Douglas DC-2 was one of the first highly successful airplanes to use the configuration that has become standard for modern transport category aircraft cantilever low-wing construction, with retractable landing gear. “Pursuit of Excellence”  JOCSON COLLEGE DID YOU KNOW? Douglas DC-2 was one of the first highly successful airplanes to use the configuration that has become standard for modern transport category aircraft cantilever low-wing construction, with retractable landing gear. “Pursuit of Excellence”  JOCSON COLLEGE STRESSED-SKIN WING CONSTRUCTION Two major improvements made over the conventional method of machining wing skins. Chemical milling, aluminum alloy is treated with an acid-resisting coating Provided a much stronger wing skin that had a reduced tendency to crack. “Pursuit of Excellence”  JOCSON COLLEGE STRESSED-SKIN WING CONSTRUCTION Electrochemical machining After the skin is immersed in a salty electrolyte, This electrolytic process eats away the metal at a rapid rate without actually touching the metal, Cause stress concentration points where cracks could form. “Pursuit of Excellence”  JOCSON COLLEGE STRESSED-SKIN WING CONSTRUCTION To gain the maximum amount of stiffness for the weight, Some aircraft have wing skins made of laminated structure in which thin sheets of metal are bonded to a core of fiberglass, paper, or metal honeycomb material. “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE MAIN ROTOR BLADE WITH HONEYCOMB “Pursuit of Excellence”  JOCSON COLLEGE STRESSED-SKIN WING CONSTRUCTION Some airplanes that travel at supersonic speeds have outer skins made of stainless steel, brazed to cores of stainless steel honeycomb. North American XB-70 Valkyrie “Pursuit of Excellence”  JOCSON COLLEGE CONTROL SURFACE CONSTRUCTION Almost all new metal airplanes have their control surfaces covered with either thin aluminum alloy, magnesium alloy sheets, or in some cases, advanced composite materials. “Pursuit of Excellence”  JOCSON COLLEGE CONTROL SURFACE CONSTRUCTION Flutter is a primary design consideration for any control surface. Occurs when an out-of-balance condition causes a control surface to oscillate in the air stream “Pursuit of Excellence”  JOCSON COLLEGE CONTROL SURFACE CONSTRUCTION Many surfaces have extensions ahead of the hinge line on which lead weights are installed. To retain the flutter resistance, most control surfaces must be statically balanced anytime repairs or modifications are made, including painting. “Pursuit of Excellence”  JOCSON COLLEGE CONTROL SURFACE CONSTRUCTION To gain rigidity from the thin metal covering, many manufacturers corrugate the external skins. The stiffness provided by the corrugation minimizes the amount of substructure needed, thereby reducing the weight of the control. “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE “Pursuit of Excellence”  JOCSON COLLEGE CONTROL SURFACE CONSTRUCTION Where a substructure is required The control surfaces are constructed with stamped or forged ribs and spars to form a monocoque or semi-monocoque frame. “Pursuit of Excellence”  JOCSON COLLEGE CONTROL SURFACE CONSTRUCTION The hinges typically use thin wire to hold the hinge halves together Which require periodic checks to verify their condition, security of attachment, and wear. “Pursuit of Excellence”  JOCSON COLLEGE END OF PRELIM “Pursuit of Excellence”  JOCSON COLLEGE CONTROL SURFACE CONSTRUCTION Excessively worn hinges often cause flutter to be induced into the control, in a similar manner to an out-of-balance condition. “Pursuit of Excellence”  JOCSON COLLEGE CONTROL SURFACE CONSTRUCTION Always lock the control surfaces into a fixed position when parking the aircraft. Control locks can be `themselves. “Pursuit of Excellence”  JOCSON COLLEGE CONTROL SURFACE CONSTRUCTION This prevents damage to the control surfaces by preventing the wind from blowing the controls against the stops. Using control locks also reduces wear to the control hinges. All control locks should be marked in a distinctive fashion to preclude being inadvertently left in place during preflight inspection. “Pursuit of Excellence”  JOCSON COLLEGE AIRFOIL CONTROL & AERODYNAMIC CONFIGURATIONS The largest percentage of airplanes use standard primary control surface configurations ailerons, rudder, and elevator. “Pursuit of Excellence”  JOCSON COLLEGE AIRFOIL CONTROL & AERODYNAMIC CONFIGURATIONS Large, transport category aircraft use additional control surfaces to provide different amounts of control authority during high- and low-speed flight. “Pursuit of Excellence”  JOCSON COLLEGE AIRFOIL CONTROL & AERODYNAMIC CONFIGURATIONS Large, transport category aircraft use additional control surfaces to provide different amounts of control authority during high- and low-speed flight. “Pursuit of Excellence”  JOCSON COLLEGE AILERONS Located near the wing tips and hinge to the aileron spar to become part of the trailing edge of the wing. Large jet transport aircraft have two sets of ailerons; one in the conventional outboard location, and one inboard. “Pursuit of Excellence”  JOCSON COLLEGE AILERONS For slow-speed flight, both sets of ailerons operate to provide the needed lateral control, For high-speed flight, only the inboard, or high-speed, ailerons are active. “Pursuit of Excellence”  JOCSON COLLEGE AILERONS If both sets were active at high speed, the aerodynamic effectiveness of the out- board ailerons would be too great, possibly causing too rapid movement, thereby inducing over-control. “Pursuit of Excellence”  JOCSON COLLEGE SPOILERS Are control devices that destroy lift by disrupting the airflow over a portion of the wing. Thereby allowing a rapid rate of descent, They are simply structural slabs that are stowed flush with the airfoil surface that can be deployed by the pilot to swing upward into the air stream. “Pursuit of Excellence”  JOCSON COLLEGE SPOILERS They can be used as speed brakes, which allow the pilot to slow the airplane by increasing parasite drag. On the ground, spoilers can be raised to help increase braking efficiency. “Pursuit of Excellence”  JOCSON COLLEGE SPOILERS When spoilers are retracted, they fold down to eliminate the discrupted airflow and drag. Part of the secondary flight control system. “Pursuit of Excellence”  JOCSON COLLEGE QUESTION AND ANSWER “Pursuit of Excellence”  JOCSON COLLEGE REFERENCES BODY TEXT “Pursuit of Excellence”  JOCSON COLLEGE Thank You For Your Attention “Pursuit of Excellence”