M7.12 Flashcards
What is the function of a gear?
a) Transmission of heat
b) Transmission of power through motion
c) Storage of power
b) Transmission of power through motion
What is a common cause of gear failure or premature wear?
a) Excessive backlash and/or poor lubrication
b) Excessive color fading
c) Overuse of power
a) Excessive backlash and/or poor lubrication
Which of the following are all types of gear wear?
a) Overload wear, Pitting & spalling, Cracking and breakage, Interference wear, Abrasive wear
b) Friction wear, Lubrication wear, Heat wear, Rust wear
c) Speed wear, Color wear, Stress wear
a) Overload wear, Pitting & spalling, Cracking and breakage, Interference wear, Abrasive wear
What happens when heavy contact occurs between gear teeth during overload wear?
a) The lubricant is squeezed out, and micro-welds form
b) The teeth become sharper
c) The gear teeth cool down and smoothen
a) The lubricant is squeezed out, and micro-welds form
What causes overload wear in gears?
a) Sliding action that removes metal from the gear surface and forms micro-welds
b) Excessive lubrication that causes the gear to slip
c) Too much power being transmitted through the gear
a) Sliding action that removes metal from the gear surface and forms micro-welds
What causes pitting and spalling in gears?
a) Thin oil films and high temperatures
b) Excessive lubrication and low temperatures
c) Too much power being transmitted
a) Thin oil films and high temperatures
What is spalling in gears?
a) A fine crack that causes chunks of metal to flake away
b) The formation of burrs on the tooth edge
c) A smooth, polished surface
a) A fine crack that causes chunks of metal to flake away
What usually causes cracking in gears?
a) Failure in the heat treatment process or improper machining
b) Overuse of lubrication
c) Excessive gear speed
a) Failure in the heat treatment process or improper machining
What causes interference wear in gears?
a) Misalignment of gears or improper mating of the teeth
b) Excessive lubrication
c) Overuse of power transmission
a) Misalignment of gears or improper mating of the teeth
Where does heavy contact usually occur in interference wear?
a) At teeth tips and roots
b) In the center of the gear
c) Along the outer edges of the teeth
a) At teeth tips and roots
What causes abrasive wear on gear teeth?
a) Scratching and scoring
b) Excessive lubrication
c) High-speed rotation
a) Scratching and scoring
When can wear patterns be examined?
a) Before final assembly, during service, during overhaul, or after a failure
b) Only before final assembly
c) Only during service
a) Before final assembly, during service, during overhaul, or after a failure
How can the tooth contact pattern be established prior to assembly?
a) By using a special lubricant
b) By measuring the gear teeth under a microscope
c) By using ‘Prussian blue’, a blue-dyed soft paste
c) By using ‘Prussian blue’, a blue-dyed soft paste
What does normal wear leave on the tooth face?
a) A smooth, polished surface
b) A rough, textured surface
c) An uneven surface with cracks
a) A smooth, polished surface
Which side of the tooth is concave and not under pressure during regular drive?
a) Drive side
b) Coasting side
c) Outer side
b) Coasting side
What is the purpose of backlash in gears?
a) To prevent gears from jamming and provide lubricant space and allow some thermal expansion
b) To increase gear speed
c) To improve the color of the gears
a) To prevent gears from jamming and provide lubricant space and allow some thermal expansion
What is backlash in gears?
a) The play between mating tooth surfaces at the tightest point of mesh
b) The amount of lubricant in the gears
c) The pressure applied on the gear teeth
a) The play between mating tooth surfaces at the tightest point of mesh
What can affect the amount of backlash in a pair of mating gears?
a) Change in center distance, variance in tooth thickness, and temperature ranges
b) The type of lubricant used
c) The color of the gear teeth
a) Change in center distance, variance in tooth thickness, and temperature ranges
What is minimum backlash?
a) Occurs when the gears are not properly aligned
b) Occurs when there is too much lubricant between the gears
c) Occurs when all tolerances give the shortest center distance and the thickest teeth at the highest point of pitch line runout
c) Occurs when all tolerances give the shortest center distance and the thickest teeth at the highest point of pitch line runout
What is maximum backlash?
a) Occurs when the gears are too small
b) Occurs when all tolerances give the greatest center distance and the thinnest teeth at the lowest point of pitch line runout
c) Occurs when the gears are not properly aligned
b) Occurs when all tolerances give the greatest center distance and the thinnest teeth at the lowest point of pitch line runout
What is backlash tolerance?
a) The variation in tooth thickness
b) The allowable amount of backlash
c) The amount of temperature change the gears can handle
b) The allowable amount of backlash
What is backlash variation?
a) The speed at which the gears turn
b) The difference between the maximum and minimum backlash occurring in a whole revolution of the larger mating gear
c) The amount of lubrication in the gears
b) The difference between the maximum and minimum backlash occurring in a whole revolution of the larger mating gear
Which tools can be used to measure backlash in a gear train?
a) DTI or feeler gauge placed against the gear teeth
b) A torque wrench
c) A digital thermometer
a) DTI or feeler gauge placed against the gear teeth
What should be checked during the primary chain inspection?
A) Sprocket condition
B) Smoothness of chain over sprockets
C) Chain color
B) Smoothness of chain over sprockets
What is the purpose of the secondary inspection of the chain?
A) To check for proper lubrication
B) To measure deflection or elongation under load
C) To check for visible cracks
B) To measure deflection or elongation under load
What is the typical deflection/elongation limit for a chain under the correct tension?
A. 1.5% to 3%
B. 5% to 8%
C. 10% to 15%
A. 1.5% to 3%
What should you do if a chain shows signs of corrosion during inspection?
A. Wash the chain with water.
B. Replace the chain.
C. Paint over the corrosion.
B. Replace the chain.
What must a chain be inspected for during maintenance?
A. Damage, cleanliness, adequacy of lubrication, and absence of corrosion.
B. Chain color, sprocket size, and tightness.
C. Sparkle, noise, and sprocket wear.
A. Damage, cleanliness, adequacy of lubrication, and absence of corrosion.
What is a recommended correction for pin galling due to inadequate lubrication?
A. Replace the chain and sprocket.
B. Reduce load or chain drive speed and provide proper lubrication.
C. Eliminate corrosion by painting the chain.
B. Reduce load or chain drive speed and provide proper lubrication.
What is a probable cause of tight joints in a chain?
A. Dirt, foreign substances, or corrosion in the joints.
B. Misaligned sprockets.
C. Static pressure at the pin and linkplate fit.
A. Dirt, foreign substances, or corrosion in the joints.
What is the correction for hooked sprocket teeth?
A. Realign the chain.
B. Replace the chain and sprocket.
C. Increase lubrication.
B. Replace the chain and sprocket.
What causes cracked plates in a chain due to fatigue?
A. High overloads beyond the chain’s dynamic capacity.
B. Exposure to moisture or water in the lubricant.
C. Rubbing against guides
A. High overloads beyond the chain’s dynamic capacity.
What is the correction for fractured plates caused by high tension overload?
A. Replace the chain and correct the cause of the overload.
B. Increase lubrication to compensate.
C. Reduce speed without replacing the chain.
A. Replace the chain and correct the cause of the overload.
What environment commonly causes stress corrosion in chain plates?
A. Misaligned sprockets.
B. Severe rusting or exposure to acidic/caustic mediums.
C. High-speed operation.
B. Severe rusting or exposure to acidic/caustic mediums.
What causes enlarged holes in a chain?
A. High overload.
B. Dirt in the joints.
C. Misalignment of the sprockets.
A. High overload.
What is the correction for a chain rusted due to moisture?
A. Replace the chain, protect it from moisture, and improve lubrication.
B. Clean the chain thoroughly and continue using it.
C. Reduce the load and align the sprockets.
A. Replace the chain, protect it from moisture, and improve lubrication.
What is the probable cause of abnormal wear on a chain rubbing against guides (Worn Contour)?
A. Excessive internal friction.
B. Abnormal chain alignment or insufficient clearance.
C. Exposure to acidic or caustic mediums.
B. Abnormal chain alignment or insufficient clearance.
What should be done if a chain has turned pins due to excessive internal friction (Abnormal Protrusion or Turned Pins)?
A. Clean the chain and continue using it.
B. Replace the chain, improve lubrication, and eliminate overload.
C. Tighten the chain joints to avoid further movement.
B. Replace the chain, improve lubrication, and eliminate overload.
What are common materials used to manufacture sprockets?
A. Alloy, hard fibre material, and plastic.
B. Steel, rubber, and carbon fibre.
C. Aluminum, glass, and ceramic.
A. Alloy, hard fibre material, and plastic.
What is the main role of a sprocket?
A. To support a chain’s weight at rest.
B. To convert rotary motion into linear motion or vice versa.
C. To act as a decorative part of machinery.
B. To convert rotary motion into linear motion or vice versa.
What does an idler sprocket do in a chain system?
A. Drives the chain with extra force.
B. Supports the chain in long chain runs.
C. Reduces chain tension automatically.
B. Supports the chain in long chain runs.
What steps are included in inspecting a sprocket?
A. Clean the sprocket and check for worn teeth or misalignment.
B. Lubricate the sprocket and measure its weight.
C. Polish the sprocket and tighten its teeth.
A. Clean the sprocket and check for worn teeth or misalignment.
What are some advantages of drive belts compared to chain drives?
A. They are quieter, smoother, and do not require lubrication.
B. They carry a heavier load and require less maintenance.
C. They are slower and more resistant to wear.
A. They are quieter, smoother, and do not require lubrication.
What must drive belts and pulleys be inspected for during maintenance?
A. Alignment and weight distribution.
B. Wear, degradation, cracking, splitting, chipping, and fraying.
C. Noise and operational speed
B. Wear, degradation, cracking, splitting, chipping, and fraying.
What must be done if defects like cracking, splitting, chipping, or fraying are found during an inspection?
A. Clean and re-tension the belt.
B. Replace the belt or pulley.
C. Reduce the load on the belt.
B. Replace the belt or pulley.
How is belt tension typically checked?
A. By measuring the length of the belt.
B. By applying a force to the belt midpoint and measuring the deflection.
C. By observing the belt’s color during operation.
B. By applying a force to the belt midpoint and measuring the deflection.
What are the three basic types of screw jacks used in aviation?
A. Worm and peg, worm and nut, recirculating ball mechanisms.
B. Worm and wheel, hydraulic piston, linear actuators.
C. Gear-driven, belt-driven, chain-driven mechanisms.
A. Worm and peg, worm and nut, recirculating ball mechanisms.
Why is the ‘worm and peg’ mechanism rarely used on aircraft?
A. It is too expensive to manufacture.
B. It causes excessive backlash, leading to localized wear.
C. It requires constant lubrication to function.
B. It causes excessive backlash, leading to localized wear.
What is the recirculating ball mechanism commonly used for on aircraft?
A. Flap drive system.
B. Landing gear adjustment.
C. Engine control system
A. Flap drive system.
What is a key characteristic of the recirculating ball mechanism?
A. It uses ball bearings that recirculate through the gear as it turns.
B. It uses a worm screw to drive the nut.
C. It operates without any moving parts.
A. It uses ball bearings that recirculate through the gear as it turns.
How does the nut in a recirculating ball mechanism move along the screw thread shaft?
A. The nut rotates with the screw thread shaft.
B. The nut moves in a linear direction but does not rotate with the screw.
C. The nut remains stationary while the screw moves.
B. The nut moves in a linear direction but does not rotate with the screw.
What is another name for the recirculating ball mechanism?
A. Worm and nut mechanism.
B. Ball screw actuator.
C. Linear drive mechanism.
B. Ball screw actuator.
What type of friction does the recirculating ball mechanism reduce compared to the worm and nut mechanism?
A. High friction.
B. Low friction.
C. No friction.
B. Low friction.
What are the two primary maintenance concerns when inspecting a screw jack arrangement?
A. Lubrication and backlash.
B. Overheating and corrosion.
C. Misalignment and vibration.
A. Lubrication and backlash.
What feature allows the inspection of whether the adjustable end is sufficiently screwed onto the control rod?
A. A witness hole in the adjustable eye-end fitting.
B. A visible marking on the rod.
C. A torque measurement.
A. A witness hole in the adjustable eye-end fitting.
What is a key feature of the push-pull control system?
A. Adjustable and lockable threaded end fittings with left and/or right-hand threads.
B. Hydraulic fluid for smooth operation.
C. A flexible rod that bends to accommodate tension.
A. Adjustable and lockable threaded end fittings with left and/or right-hand threads.
What is the primary purpose of a bell crank?
A. To transmit force or motion and permit a change in direction of that force or motion.
B. To adjust the tension of control rods.
C. To act as a bearing in mechanical systems.
A. To transmit force or motion and permit a change in direction of that force or motion.
Is any adjustment required for a bell crank itself?
A. No, bell cranks usually require no adjustment.
B. Yes, the bell crank must be adjusted for tension.
C. Yes, the bell crank must be lubricated regularly.
A. No, bell cranks usually require no adjustment.
