M6 Past Paper PDF

M6 Consist of Alternating Layers of Aluminum and Glass Fiber pre-peg layers. Ans. GLARE (Glass Aluminum Reinforced Laminate) between two materials that come into contact. "Entrapment area" (uwang sa gitna) Ans. Crevice Corrosion Identified by its characteristics worm-like trace of corrosion pro...

M6 Consist of Alternating Layers of Aluminum and Glass Fiber pre-peg layers. Ans. GLARE (Glass Aluminum Reinforced Laminate) between two materials that come into contact. "Entrapment area" (uwang sa gitna) Ans. Crevice Corrosion Identified by its characteristics worm-like trace of corrosion products beneath the point film. Ans. Filiform Corrosion Result in the rubbing movement between two heavily loaded surfaces and can eventually cause cracking fatigue. Ans. Fretting Corrosion Corrosion on aluminum and magnesium. White, powder deposit, Starts on the surface of a material and then extends vertically into the material Ans. Pitting Corrosion Made from small strands of molten silica glass and then spun together and woven into cloth but weighs more and has less strength than reinforcing material Ans. Fiberglass Characterized by its YELLOW COLOR, lightweight and its excellent tensile strength. Ans. Aramid Very Strong and stiff and is used for its rigid, strong properties. Ans. black graphite/carbon fibre Area measured materials which are not woven and made out of or cut or non-cut, multidirectional laying fibers which are fixed by sprays on binder. Ans. Mats Airbus prints a wire number on the wires, the first four-digit number designates Ans. ATA-Chapter This type Bearings are often lubricated by water, the water also acts as a coolant, because these bearings tend to retain heat. Ans. Synthetic Bearing Rivet Diameter of Ms20292881D5-8 Ans. 5/32 (Tas yug rivet size pag -8 yung dulo, 5/32. Pag -12 5/16) Identify the diameter of bolt BAC1527D5-12 Ans. 5/16 Damage classification in composite Ans. Allowable, Repairable, Non-Repairable Pins includes grooves onto which a collar is swaged Ans. Lockbolts Airbus Customer wire number Ans. 9000-9999 It is the sheathing of wires and cables with an electrically conductive material in order to prevent electromagnetic fields from either entering or escaping from wires and cables. Ans. Shielding The property of metal which allows to be deformed without breaking Ans. Toughness The stress at which a material in tension, compression or shear will fracture. Ans. Ultimate strength The maximum stress that can be applied to a material without permanent deformation Ans. Yield strength Any wetting with acidic fluids or mordant on the surface can lead to Ans. Hydrogen embrittlement When the stress on the area is a combination of tensile, compressive, shearing, twisting Ans. Combined Stress A load that is uniformly distributed over a certain area and also the force per unit of area expressed is PSI (pounds per square inch) Ans. Unit stress or stress A rigid body in which the constituent particles are arranged in a repeating pattern Ans. Crystal Small surface damage such as scratches, nicks, or corrosion Ans. Notch Sensitivity Applicable for steel components, which are hardened and have to be softened for mechanical processing, also called the zero state / certain temperature. Ans. Soft Annealing A chemical reaction, generally carried out in a presence of a catalyst Ans. Polymerization A chemical reaction between two similar or dissimilar basis units which have at least two functional groups Ans. Polycondensation Reaction of two different types of molecules when reactive groups are brought together Ans. Polyaddition Bonding Process of Honeycomb Fabrication: Ans. Corrugation and Expansion A plastic. after cooling, the resin sets and hardens in given form. Hardening is Reversible Ans. Thermoplastic Resin Resin would be damaged when heat is applied. Hardening is Irreversible Ans. Thermosetting resins Damage to a surface caused by scuffing, rubbing, or scraping of the component Ans. Abrasion A deformity caused by extraneous forces, which are applied to the structure Ans. Dent Corrosion that is a combination o stress and corrosion Ans. Stress Corrosion A piece of rod, threaded at each end with a plain portion in the middle Ans. Stud A piece of hexagonal metal bar, drilled and tapped through its axial center-line Ans. Stud box Used extensively to secure thin-gauge sheet metal parts where nuts and bolts are either impractical or too expensive Ans. Self Tapping Screws Spring steel washer with slanting serrations in its internal or external circumferences Ans. Shakeproof Washer Have a very low starting resistance and are suitable for high rotation speeds Ans. Ball Bearing Is the most positive and satisfactory method of safetying cap-screws, studs, nuts, bolt-heads and ad turnbuckles Ans. Wirelocking Are used to connect two shafts with each other Ans. Couplings With some alloys, Hardening of the material at room temperature Ans. Natural aging Cable are connected, Change in cable tension is effective by Ans. Turnbuckle Must never be lubricated Ans. Turnbuckle What is combined with iron to increase strength Ans. Carbon Crimp two elements onto a wire, special crimping tool Ans. Cold welding Substance used to bond two or more surfaces together Ans. Adhesives Effectiveness of Adhesive.. Ans. Resistance to slippage and shrinkage, Malleability, Cohesive strength, Adhesion, It deforms its ack when a tension load is applied at the front and Pull through.. Ans. Blind Rivets Solid rivet is formed by deformation of the shank Ans. Upset head These cables consists of four twisted AWG 24 wire with common shield Ans. Quadrax Cable Thermocouple also known as Ans. Temperature probes Aim of Heat treatment Ans. To increase strength By heating (soft anneal) these alloy to a certain temp. and subsequent quenching Ans. Aging time Method that uses diamond tip to get depth Ans. Rockwell Test Method that uses steel ball to get area Ans. brinell Test Teat: Ans. 2017 aluminum allow (D) Raised Double Dash: Ans. 2024 aluminum allow (DD) Dimple: Ans. 2117 aluminum allow (AD) Raised Cross: Ans. 5056 aluminum allow (B) When the separation of plies occurs in a multi-laminate materials Ans. Delamination When a separation of material, stringer to skin, occurs due to an adhesive failure Ans. Debonding Amount of time you have to work with the resins, will also reduced Ans. Pot life Time which the product is still good in an unopened container and varies from product to product Ans. Shelf life Represent the 2.4mm = max 2 thread pitches LEAD the mating pair advances axially 67) T< 2.4mm = no thread pitches w/in the hole 68) Maximum of 3 washers may be used to adjust a grip length a) (1 under the head, 2 under the nut) 69) A piece of rod, threaded at each end with a plain portion in the 78) It consists of a receptacle , stud and cross pin. It has two types which middle is the fixed type and floating type a) Stud a) Airloc Fasteners 70) A piece of a hexagonal metal bar, drilled and tapped through its axial 79) used to secure bolts, screws, nuts and pins center – line a) Cotter Pins a) Stud box 80) Given to a specially – shaped piece of metal that is used to transmit at 71) Used extensively to secure thin – gauge sheet metal parts where nuts considerable mechanical power from a shaft to hub and bolts are either impractical or too expensive a) Keys a) Self-Tapping Screws i) A. Taper Keys Nuts (4) Hollow Saddle Key- is hollowed to fit the radius of the 1.Non- Self Locking Nuts (4) shaft -Are used with drilled shank hex head bolts, clevis bolts, eye bolts and Flat saddle key- is a rectangular or square section that is rivets and is designed to lock cotter pin or wirelocking driven into a keyway in the hub and bears upon a flat on Classifications: the shaft Shear Castle Nut – used only for shear load on clevis bolts Gib headed key- is fitted into keyways which are Castle Nut- Are designed to fit on standard airframe bolts and machined partly in the shaft and partly in the hub. It is may be used when the bolt is subjected to either shear or tensile strength capable of transmitting a much greater driving load than the saddle type keys Slotted Engine Nut- designed for use on aircraft engine and is not approved for airframe use. Made of Heat- treated steel Feather key- is used when axial movement is required Wing Nut- intended for use on hose clamps and battery between the hub and the shaft connections where the desired tightness is ordinarily obtained by Woodruff key- is made in the shape of a segment of a the use of fingers parallel sided disc similar to capital D. it is suitable for fitting 2.Locking nuts (5) not reuseable to either parallel or taper shafts. Lock nut- Is a thin, plain nut which is tightened down firmly M6.5.4 RIVETS onto the main, plain nut. 81) Deformed portion of the Rivet Nyloc Stiff nuts- has an unthreaded nylon insert permanently a) Upset Head housed at the outer end i) Selection of correct Rivet diameter is at least 3 times the Oddie Stiff nuts-Have six tongues at their outer end which are thickness of the thickest sheet being joined bent inwards to form a circle slightly less in diameter than the minor diameter of the bold thread Aluminum Alloy Rivets- Used to attach aluminum alloy components Aerotight and Philidas Stiffnuts- have slotted locking where a low-strength rivet is sufficient to hold the load extensions which are closed during manufacture to put the screwthread Monel Rivets- Without heat treatment before use, are used in steel, out of alignment titanium or aluminum alloy riveted assemblies 72) is used when a slight range of movement is necessary to ensure the Titanium Rivets - Are rivets with a cylindrical or a partial tapered shank. bolt can locate No heat treatment is necessary for this type of rivet a) Anchor Nuts 3.High- temp self- locking Nuts – temp self locking >121degC (250F) 4.Low- temp self- locking Nuts - temp self locking < 121degC (250F) 73) Permit each thread to adjust to the screw and assure full load distribution throughout the entire length of the thread, Protection for soft material a) Heli – Coil Inserts M6.5.3 LOCKING DEVICES 74) A process of securing all aircraft bolts, nuts, screws, pins and other fasteners so that they do not work loose due to vibration a) Safetying 75) Most positive and satisfactory method of safetying and is a method of wiring together two or more units in such a manner that any tendency of one to loosen is counteracted by the tightening of the wire a) Wirelocking 76) Most common method of wire locking a) Double - Twist Method Washers 1. Spring Washers- either a single coil or square section spring with sharp corners or a double coil spring. 2. Tab Washers- is a metal washer with two or more tabs, suitable for use with plain nuts. One tab is bent against one of the flats of the nut and the other is bent over an edge of the component or fitted into 82) a process which a rivet material have to be heat treated before using or hole machined in the component. Not reusable them in the manufacturing process 3. Shakeproof Washer- is a spring steel washer with slanting serrations a) Solution Annealing( Annealed at 495o and quenched at 20o) on its internal or external circumferences i) At -18o temperature rivets can be stored for up to 7 days Quick release Fasteners ii) At -20o temperature rivets can be stored for up to 20 days 1. Pip pin - is a simple and secure, non-threaded fastener, allowing rapid installation and removal of parts without tooling 83) the time between opening the furnace or removing the rivets from A. Ring Pull Detent Pin- A single ball locates the pin, no positive the salt bath and the complete immersion of the load into the lock quenching medium B. Double Acting Steel Pin- it is a instantaneous self locking, a) Quench Delay vibration resistant and easy application pin 84) The time, within which the rivets must be upset, at room temp. 25o 2. Camloc Fasteners – designed so that it can be quickly inserted into the a) Maximum Handling Time grommet by compression of the spring 85) A tapered bolt with a threaded end and a self – locking nut and used 77) It has 2 types which are the light duty that is used on box covers, in areas where a high fatigue performance is required access hole covers and light weight fairing and the second type which a) Taper – Lok is the heavy duty type which is used on cowling and heavy fairings 86) A combination of a rivet and a nut, resembling a hollow rivet with a) Dzus Fasteners threads inside its shank a) Rivnut 87) Combined thickness of the material to be joined 2. Journal or Roller bearings- it is the bearing that is used for a) Grip Length supporting journals, which are designed to accept forces at 88) Run along the length of a hose which are yellow, red or white stripes right angles to the drilling axis that serves to indicate whether the assembly is twisted Loads a) Lay Lines - Deal with the two kinds of loading which are the radial and thrust 89) A hose must have a 2-4% slack allowance in installation so the hose Sliding bearings won’t over extend in operation - The journal of a sliding bearing operates in a bearing box, a bearing 90) Used to support the journals of shaft and axles bushing or directly in the bearing body a) Bearings Anti friction bearings 91) Bearings for pivot journals and designed to accept forces in - Consists of the outer and inner raceway, the rolling element and longitudinal direction usually a rolling element cage (*PARTS) a) Pivot or axial bearings Types of Anti friction bearings 92) Bearing for supporting journals and designed to accept forces at right 1. Roller Bearings – are used if the occurring stresses are too - angles too the drilling axis. severe for ball bearings a) Journal or roller bearings 2. Ball Bearings- have a very low starting resistance and are 93) Bearings used with the combination of thrust and radial load suitable for high rotation speeds a) Tapered roller bearings 3. Radial Bearings- can accept forces that act radially to the shaft 94) A requirement for the long working life of bearings axis a) Adequate Lubrication 4. Axial or longitudinal Bearings- accept forces that act in the direction of the axis of the shaft 95) A type of bearing that is used where limited spaces are available Transmissions - Needle Bearing Chains 1.) Bearings that accept forces that act radially to the shaft axis - Provides strong, flexible and positive connections and are generally - Radial Bearings used wherever it becomes necessary to change the direction of 2.) Provides string, flexible and positive connections and used control runs in systems where considerable force is exerted wherever necessary to change the direction of control Chain Drives - Chains - Are suitable for pop slop power transmission with large spaces between 3.) Change of directions in chains are achieved with the use of axles when cog wheels are not available to decrease the size - Chain wheels of the spaces 4.) Power transmission for trim is achieved via Roller Chains - Chain Drive - The turnable rolls of roller chains along the flanks on the chain wheel 5.) The revolving chain is tensioned by teeth. The number of teeth should not be smaller than 12. - Chain tightener Gear Chains - Have cogged lugs which engage into the gaps between the teeth of the 6.) Used to transfer forces into cables an push rods chain wheel. The number of teeth should not be smaller than 17 - Cable Quadrants with regard to wear 7.) Used to transmit swinging or rotating movements Couplings - Torque tube transmission - Are used to connect two shafts with each other If not in use, a chain must not be put on a flat surface. It should A. Solid Couplings be carefully coiled and wrapped in a grease paper - It is used for a rigid connection between two shafts to achieved 8.) Used to prevent the gears from jamming and making contact on - Types of Couplings both sides of their teeth simultaneously. 1. Sleeve couplings - Backlash Consists of two cast iron sleeves which are fixed to the shaft ends by screws Control cables in aircraft are often 2. Disk Couplings 3/32 – 7x7(flexible cable) or 1/8 – 7x19(Extra flexible cable) Two disks are fitted to the shaft ends by screws B. Movable Couplings 9.) a cable which consist of a tension wire wound either with a - Comprise expansion couplings, hinge coupling and elastic couplings. continuous left or right hand helix winding They are used if the shafts are not in alignment or if the position of the shafts changes during operation - Teleflex control cables A. Extension Couplings 10.) A cable which is a short run, lightly loaded type of control that is Allow a small longitudinal movement of shaft in relation to other made of non-corrodible steel wire designed for “pull” operations One kind of this coupling is called the claw coupling which is also only. used as disconnectable couplings - Bowden cables B. Hinge Couplings Comprise cross links, dry disk joins and ball and socket joints They are Heat treatment of Al. Rivets used in cases where the direction of the axes of the shafts Solution Annealing linked to the couplings change in a certain angle - The material is annealed at 495 degrees for a certain time and after C. Cross links that it is quenched at 20 degrees cold water. The material can be deformed without high loads and crystal damage Are suitable to transfer stronger forces, such as in automobiles - All rivets 3.1324, 2017,2017 A and 2024- alloys must be stored at -18 D. Dry Disk Joints degrees. At this temperature, the rivets can be stored up to 7 days and Consist of elastic clutch disks, each connected to a flange at the at -20 degrees, it can be stored up to 20 days end of the shaft. The angle around which is the shaft axes can Taper Lok fastener rotate is 8 degrees - Is a tapered bolt with a threaded end and a self locking nut. It also Gear Drives includes it’s own washer. It transfer rotational movement at low speeds without sleep. Lock bolts Power Transmissions - Is a two piece assembly that consists of A pin with a protruding or Power transmission in parallel shafts is achieved by spur wheels or counter sink head and a collar that is waged on to the locking grooves by a cog wheel with internal toothing and pinion. on the pin shank to secure the pin when it is installed In case of shafts with axes that stand perpendicular to each other, Riv nuts power transmission is achieved by Bevel Gears - Is a combination of a rivet and nut, resembling a hollow rivet with If the axes are crossing, power transmissions is achieved by a threads inside its shank worm and worm gear by a Helical Gear Bearings Spur Gears - Are used to support journals of shafts and axles - May have straight teeth, slanting teeth and herring bone teeth. Types of bearings A. Slanting teeth 1. Pivot or Axial bearings – it is the bearing that is used for pivot Operate much more silently than wheels with straight teeth, journals, which are designed to accept forces in a longitudinal because at all times, several teeth are engaged direction B. Herringbone Teeth The axial forces eliminate each other. Because of this, herringbone gears are used for the transmission of large forces Gear Units - Transmit the rotational speed of the driving engine in a way that the shaft or spindle turns with the required rotation speed. It can also change the direction of the rotational movement Helical Gears - Are only suitable for the transfer of small forces, because the flanks of the teeth contact in only one spot Worm Gears - Large transmissions can be achieved with worm drives when the drive is created by the worm. When a one- toothed worm turns once, the respective worm gear moves only the distance of one tooth Bevel Gears - Bevel gears that operate together are two conical surfaces which roll without slipping because of their tooth system Toothed wheel Gears - There are two types of variable gears which are the stepped transmission gears and the driving key type transmission gears A. Stepped transmission Gears The wheels of variable gears are engaged and reach the desired rotational speed by moving them sideways. B. Driving key type Gears Can only be used to transmit small forces at low rotational speed. It does not need much space and can change gears during operations Friction Gear - Has a simple set up. The driving friction wheel is movable, so that the rotation speed of the driven friction disk is infinitely variable Coney Pulley Drive - Is suitable for transmission of smaller forces at high rotational speed. Transmission Component Control Mechanism A. Cables Are the primary transmission components in airplane without fly by wire system. It is versatile, offer movement free of play, problem- free transmission on a weight saving basis and can thus be routed into almost every area via guiding pulleys Cables used in airplane construction has a minimum tensile strength of 1200N/mm2 at a breaking elongation of 2 or 7% B. Push rods Are used to operate rudders, auxiliary rudders, flaps etc. It can transmit pulling and pushing forces C. Quadrants Forces are transferred to cable via cable quadrants and the forces of the cables are also transmitted to push rods via cable quadrants D. Torque Tube Transmissions Swinging or rotating movements are transmitted by Torque tube transmissions