Fatigue and Stress | Wheels, Rims, and Tyres Flashcards
There are _ main types of wheels:
- Well-based
- Detachable flange
- Split hub
Detachable flange tyres can have one side removed by ___
taking out a locking ring
Wheels are generally made from ___
aluminium alloys
Using aluminimum allows ___ space between the rim and the brake for cooling purposes
more
___ ___ are fitted to the wheel rims to reduce the risk of excessive heating causing a retracted tyre to burst within the wheel well
Fusible inserts
A fussible insert is ___
A hexagonal stud with bored centre and a rubber plug. They melt at a pre-set temperature to blow out the rubber plug and deflate the tyre, prior to an explosion
The average life of a tyre is around ___ landings between remoulds, and around _ to _ retreads
100
2-3
The most likely time for creep is when the tyre is ___
newly fitted
Creep is the ___ movement of the tyre in relation to the wheel ___
circumferential flange
An engineer should be consulted when when the creep exceeds ___
half of the distance of the creep mark
A red band is a ___ mark
balance
A grey/green mark is a ___, which allows
awl hole, trapped gas between plies to esacpe
Up to 24 inches in diameter, _ inch(es) of creep is/are allowed
1 inch is
Above 24 inches in diameter, _ inch(es) of creep is/are allowed
1.5
A speed rating is present if the tyre is rated above ___ mph
160
Tyres are normally inflated with the weight (off) the wheels and _% is added to compensate
off 4
Air can escape through either ___
valve or carcass
Air cannot escape through the ___ with tubeless tyres
carcass
Cold tyres are rejected if they are over __% below pressure
10
Betwen _% and __% below pressure, they can be reinflated and checked the next day, then rejected if they are still more than _% below
5 10 5
A tyre below _% can be reinflated, but must be rejected if it reaches the same value by the next day
5
Hot tyres are rejected if they are more than __% below the loaded pressure of other tyres on the same leg
10
Under-inflated tyres wear most on their ___, and over-inflation leads to ___ wear
shoulders crown
Tyres should be inflated with ___ as it has a reduced pressure change with altitude, though ___ ___ can also be used
nitrogen, dry air
Nitrogen must be used to inflate tyres on aircraft over ___kg that have retractable landing gear
5700
Typical inflation pressures are __ to __ psi for grass and ___ psi for paved
30 50 200
The permissable load ___ as inflation pressure decreases
decreases
Pre-flight inspection of tyres should include:
- Creep within limits
- No cuts/scores/swelling/bulges
- No embedded objects
- No signs of heat damage
- Correct inflation
Tyres are classified by ___
- Load
- Ply
- Speed rating
The ply rating identifies a tyre by its maximum recommended ___ and ___
load and pressure
Ply rating is the index of tyre ___
strength
Most tyres are ___ply, to ensure even load distribution, with multiple layers of nylon ply at alternating angles to the tread centreline
cross
With radial tyres, the ply runs at __ degrees, which helps with cornering.
90
High speed demands are covered by ____ the tread
reinforcing
Radials are ___ flexible and can offer ___ weight, but tend to be ___ retreadable than a bias ply with weaker sidewalls.
more low less
Tread is made from a compounded rubber that must resist ___
- Wear
- Cutting
- Chunking
- Heat build up
The tread includes the __ and __ of the tyre
crown shoulder
The most common pattern is ___ tread
ribbed
The ribs along the length of the circumference help with ___ ___ and grooves between them allow ___ ___
directional stability, water dispersal
___ treads are best for unpaved airfields
Diamond
You can go down to the depth of the pattern ( on patterned tyres), or the marker tie bar, or _mm above the bottom of the wear indicator on ribbed tyres, and they can be repaired several times
2
A plain treaded tyre is at its limits when __ ___ is exposed
cushion rubber
A layer of rubber that is designed to improve the adhesion between tread/ITF and the casing plies is called the ___
undertread
During the retreading process, the ___ acts as the interface for the application of fresh tread rubber
undertread
The basic strength of the tyre is provided by the ___ ___
casing plies
Casing plies are layers of __ ___ coated with ___ ___ on both sides
fabric cord hi-modulus rubber
Casing plies are held in place by being wrapped around the ___ to provide the casing ply turn up
beads
The bead wire anchors the ___ to the ___ to ensure an airtight seal
tyre to the rim
Beads are bundles of ___
high tensile steel wires
The sidewall is the area of the tyre between the ___ and the ___
shoulder and the bead
The sidwall is covered with a layer of special rubber treated with ___
anti-oxidants
The sidewall protects the casing plies from the effects of ___ and offers resistance to ___ and ___
weathering cuts flexing
Tubed tyres are inflated with a ___
rubber inner tube
The tyre casing around a tubed tyre is similar to that of a ___ ___
tubeless tyre
Tubed tyres are ___ subject to sudden blowouts
less
The main problem with tubed tyres is ___ or ___ of the inflation valve after creep
bending breaking
A tubeless tyre has __ inner tube
no
Tubeless tyres are ___ to balance
easier
There is __ rubbing during taxing, they are __C cooler when running and are vented to release air trapped in the casing.
less 10
Tubeless tyres have a ___ risk of deflating through puncture
lower
A tubeless tyre has a ___ casing
radial side casing
