Book2 Flashcards
A cable that is 7 x 14? What’s it mean?
7 strands - 14 wires
How do I classify cables?
Minimum breaking load CWT
What is a lockclad cable
Aluminium tube swaged around it. It’s rigid. Thermal expansion is that to close to the structure. LESS CABLE SAG
What is the use of a turnbuckle?
Adjust tension of cables
After tension has been adjusted what needs to be checked?
If it’s in safety, lockwired, locknuts , NOT BUTTING
how to check if American turnbuckles are in safety
No more than 3 threads showing and fancy clip which is used once
How do Americanss know which side is left hand thread
A groove
British fork joints may be identified by a code marked on the shank. A grooved COLLAR indicates? A grooved SHANK INDICATES
HIGH TENSILE STEEL
HIGH TENSILE STAINLESS STEEL
Bracing wires are made from?
HIGH TENSILE STAINLESS STEEL ZINC OR CADMIUM PLATES
THE SIZE of the rod or tie is shown by a letter and number code stamped on the right hand threaded end.
E174 would indicate
E = 1/4 of inch
174 = 17.4inch long
Where would shackle pins be used?
With fork joints or fork ends
What type of loads do shackle pins take and what are they secured with?
SHEAR LOADS AND SPLIT PINS
What are shackle pins made from?
HIGH TENSILE STEEL (HTS) AND HIGH TENSILE STAINLESS STEEL (HTSS)
How are HIGH TENSILE STAINLESS STEEL SHACKLE PINS IDENTIFIED
By a dimple at the bottom and a Z on the head
How are shackle pins measured?
UNDERSIDE OF HEAD TO THE NEARER SODE OF THE SPLIT PIN HOLE
FAIR LEADS MUST NOT DEFLECT A CABLE BY MORE THAN?
3 degrees
What makes a pully
MICARTA TUFNOL AND A SEALED BEARING IN THE MIDDLE. CABLE GUARDS STOP THE CANLE COMING OFF PULLEY
Cable tension regulators are used to do what?
Take up the slack due to change in expansion
What is used to tension a un regulated system
TENSIOMETER
What type of operation does a Bowden control offer?
PULL and returns with tension spring
Compression springs are used?
Engine springs and non return valves
Bowden flex operation is
Push pull
THE RAILS IN THE BOWDEN FLEX DO WHAT?
OUTER GUIDE RAIL TAKES REACTION LOADS
CENTRE LOAD RAIL TAKES FULL LOAD
How do we identify the alignment of the centre load rail?
By flats
If the flats are horizontal, the Bowden flex will operate?
Up or down (vertically) and vice versa
Where would a Bowden flex control
Cable be found?
Engine control where inching is required
What is a teleflex cable?
Helical wire inside a conduit and engages with a gear to turn a shaft
What is the maximum bend on a teleflex cables
4 inch
What is the maximum wrap round on a single entry box unit
40 degrees
What is the disadvantage of a straight lead unit?
Can’t take high loads
Hydraulic pipes used to be made off copper, what are they made off now?
Tungum stainless steel titanium
Junction box units are installed where it’s nexcasery?
To reverse the direction of travel
Can we repair a rigid pipe?
No unless specified
What is the coupling called where the nipple is permanently fixed?
Brazed nipple silver solderd
What is the flare angle of an AGS PIPE?
32 degrees
Low pressure couplings use what to seal?
O rings and usually used for air and vapour lines
Complete couplings have?
No nipple
Advantage of a flare less coupling?
No metal fatigue. Flaring leaves the tube end in a stressed condition
How is a flare less coupling assembled?
Fitting screwed on until finger tight, then nut is turned a full turn with a spanner
AN couplings have a flare angle off?
74 degrees
What test is done after forming a flare less coupling?
Make sure the sleeve does not move backwards and forwards but can rotate
Advantage of self sealing coupling?
Not needed to be bleeded
Inverted u bends?
Must not be used. Will cause vapour locks
Sliding coupling uses what seal?
O rings
Sliding couplings are used for?
Where only air and vapour passes. Needs to be bonded. They may also be enclosed in drip shields or heat shields
V band clamps and couplings are used where and sealed how?
V band clamps are used in high temperature, high pressure environments. And sealed with metal gaskets
Tightening hose clips too tight can cause what?
Cold flow
What must we make sure off when using hoses?
The hose must be compatible with the system fluid
Corbin hose clamps are made from?
SPRING STEEL WIRE
Flexible pipes are made from?
Synthetic rubber or Teflon
Teflon hoses are made from what?
PTFE AND IS CHEMICALLY INTERT
Hoses which are located in a fire zone are required to be?
FIRE PROOF
How are the length of hose assemblies measured?
With straight end fittings, they are measured from the nipple extremities.
In the case of elbowed fittings, length is taken from the centre of the bore
What do coloured stripes on a hose indicate?
It denotes the number of layers of wire braiding in its construction
How are bearings classified?
By type of rolling element
Roller bearings use?
CST: CYLINDRICAL SPHERICAL AND TAPERED ROLLER BEARINGS IN ROTARY OR OSCILLATORY CONDITIONS
Ball bearings and tapered roller bearings can carry what loads?
Radial and axial loads
Other bearing types usually carry what?
Carry mainly radial loads
Bearings are made from what?
Low carbon steel containing nickel molybdenum and chromium.
Caged bearings are used where?
Engine applications or high speed areas
Ball bearings are divided into 4 main groups. What are they?
RADIAL
ANGULAR
THRUST
PRECISION
Crowded ball races are used only where?
Crowded ball races are used where slow rotation or oscillating movement is required
Angular contact bearings accept what loads?
Radial and axial in one direction
Thrust bearings carry what loads?
Axial loads. And heavy loads at low speeds
Roller bearings may be divided into three main groups which are
CST - cylindrical, spherical and tapered rollers
Needle roller bearings are designed for what loads? And what movement
Radial loads where movement is oscillatory
Cylindrical roller bearings carry?
Greater radial loads than smilies size ball bearings
Tapered roller bearings accept?
Simultaneos radial and axial loads in one direction
In a tapered roller bearing the cup is located?
On the outside and the inside is the cone
Plain bearings are made from?
Sintered bronze
A type of damage occurs on needle roller bearings because they don’t rotate as well what is it?
Brinelling
What is the point of bearing pre load?
Rigid bearing metal
To metal contact
Springs behave?
Elastically under load
Springs are made from?
Piano wire which is a high carbon steel
Also made by either a hot or cold working process
Protective coatings for springs can withstand temps of up to?
250 degrees and made from plastic zinc nickel chromium or tin
Extension springs have what to prevent over stressing
Mechanical stops
What do we know about piston engine valve springs
Unevenly spaced and Progressive rate springs
Conical compression springs replace cylindrical compression springs when
the space in the axial direction is limited
What is spring rate?
Spring rate of a spring is the load required to produce a unit of deflection
Compression springs are used where?
Flow control valves in engine and airframe systems
Conical helical compression springs are used?
In ball type non return valves in hydraulic components
Tensions springs are used?
As return springs in remote control systems and as elevator down springs
Spiral springs are used where?
Used in instruments to eliminate, lost motion or backlash in gear trains
Cylindrical helical torsion springs are used where?
Crew seats and escape
Hatches
Leafy springs used where?
Light a/c 1/4inch eliptocal tailwheel
Shock absorbers
What are gears?
Toothed wheels to transmit power between components
Smaller gear is called what?
Pinion
If the gear drives the pinion,. What does this mean?
Speed increaser
If the pinion drives the gear what does this mean?
Speed reducer
When one gear drives another they turn?
In opposite directions
If it is required that they both turn in the same direction what is used?
An idler gear
What is the name of the tooth above the pitch circle
Addendum
What is the name of the tooth inside the pitch circle
Dedendum
Why is the involute curve found to be the best?
Because it transmits power most effectively
The onvloute curve is the
Shape of the tooth
What is backlash?
The play between the teeth
If the teeth of one gear is set too tightly to the teeth of another? There will be no?
Backlash
What does this result in?
Gears not being lubricated properly and overheating of gears
How is backlash measured?
DIAL TEST INDICATOR DTI AND FLAG
What is the hunting tooth used for?
To reduce wear
In gears wear can further be reduced how?
By making the pinion harder
What do we know about the axis on hypoid gear?
That they will never meet
Spur gears transmit power between?
2 parallel shafts
Helical gears can transmit power?
Between shafts at any angle to each other
Helical gears are more expensive than spur gears and are normally used for
High speed operation and high load applications
Helical gears are most commonly found in
Parallel shaft drives
Bevel gears are shaped how?
Like sections of cones
Bevel gears are used to transmit power between
Non parallel shafts whose axis intersect
When axis don’t intersect the gear is known as a what?
Hypoid gear
Hypoid gears require what?
To be lubricated with an oil containing a extreme pressure additive
Conformal gears are used where?
In helicopter gear boxes
What is the advantage of conformal mesh?
That there is a area of contact between the teeth of the meshing gears
How is gear ratio worked out
Driven over driver
Does the idler affect the over all velocity ratio?
No, not at all
What is the advantage of a compound gear train?
That it can produce a high gear ratio without the disproportionate gear sizes
Epicyclic reduction gears are used where?
Reduction gear assemblies of turbo prop engines and helicopter gear boxes
Each tooth of a bevelled gesr has a
Heel and a toe
The patterns of gears taken by using what?
A Prussian blue to leave an imprint on the gear teeth
Advantage of a toothed belt over a v belt
Toothed belt won’t slip
Doesn’t need pretensioning
V belts can be?
Crossed to reverse the direction of rotation
Belts have limitations such as
They apply a radial load on the pulley bearing when tightened
Prone to slip
Bulky when transmitting high powers
Chains are used for what?
Used to convert rotary motion to linear motion where considerable force is required to be transmitted
Incorrect assembly of chains is prevented by?
The use of non reversible chains in conjunction with the approprte wheels guards and connectors
Change of direction of a straight line motion in 2 planes is achieved by using?
A bi planer block
What is the principal dimensions of a chain
Pitch
Width between inner plates
Roller diameter
