Tyres

Question 1

Creep - wheels

Answer 1

Unwanted movement of the tyre

Rotate too much - tear the inflation valve out

Monitored by the use of creep marks - does not prevent creep

Tyres up to 24 inch outside diameter - 1 inch of creep

24 inch and above - 1 and a half inch of creep

Question 2

3 types of wheel

Answer 2

Well based

Loose and detachable flange - facilitates tyre replacement

Divided or split

Question 3

Loose or detachable flange wheel

Answer 3

Made with 1 flange as part of the wheel and the other loose

Facilitates tyre replacement

Question 4

Prevention of creep - tyres

Answer 4

Maintaining the correct pressure in the tyre

Knurled flange - inner face is milled with a pattern - creates more friction - enables the bead of the tyre to lock onto the wheel flange

Tapered bead set - gives a greater area

Question 5

Common wheel materials

Answer 5

Aluminium alloy - anodised

Magnesium alloy - chromate treatment - not very common due to corrosion

Question 6

Wheels for tubeless tyres

Answer 6

Have an “O” ring seal between the wheel parts to prevent leakage

Unlike tubed wheels the valve is built into the wheel itself and is thus not effected by creep

Question 7

Fusible plugs and when is it most likely going to be used

Answer 7

Fusible insert melts at a pre-set temp to allow for a controlled deflation of the tyre before a blow out

Will probably melt following a max weight RTO

Fitted on the wheel rim

Question 8

Different types of tyre

Answer 8

Tubed
Tubeless
Cross ply and radial - down to the construction

Question 9

Type of tyres fitted to a/c and they are inflated by

Answer 9

Pneumatic tyres inflated with nitrogen

Nitrogen is intert

Question 10

The tyres flexible casing is made of

Answer 10

Rubber coated rayon, cotton or nylon ply cords

Wrapped around beads at the ends of the tyres

Question 11

The bead is made from

Answer 11

Steel wires

Question 12

Which direction should you aprch the tyre from

Answer 12

Anywhere but abeam - sidewall is the weakest part of the tyre

Question 13

Purpose of the “vulcanised” layer

Answer 13

For tubeless tyres - coating on the inside layer of the tyre

Makes the tyre permeable - provides a gastight seal

Question 14

Ply rating

Answer 14

An indication of the tyre strength

Question 15

Tread

Answer 15

Made from rubber - transport a/c generally have ribbed tyres

Question 16

Tubeless tyre and adv over tubed

Answer 16

No inner tube contain the gas

Gas pressure is maintenance over a longer period

Penetration cover - no rapid loss of pressure

More resistant to blows and rough handling

No valve damage due to creep

7.5% weight saving

Question 17

Bias and cross ply

Answer 17

Plies are laid in pairs with cords placed at 90* deg to each other

Question 18

Radial

Answer 18

Plies are laid from bead to bead

Question 19

Retread

Answer 19

New tread heat bonded onto old caucus

Question 20

Remould

Answer 20

Brush off the excess rubber to the caucus then remould the tyre

Cost efficient

Question 21

How many times can you retread/remould the tyre

Answer 21

As many times

If caucus is damaged - tyre needs to be replaced

Question 22

Schrader valve

Answer 22

Operates as a non return valve for inflating the tube

Valve is not a perfect seal and has to be fitted with a metal cap

Metal with a rubber insert

Question 23

Weight of the a/c will cause a pressure increase of the tyres by

Answer 23

4%

This will increase by a further 10% in service

Question 24

Types of tyre tread

Answer 24

Ribbed - most common

Blocked - for rough surfaces

Question 25

Chinned tyre

Answer 25

Indented on the shoulder

Fitted to the nosewheels of a/c with fuselage mounted engines to prevent water ingestion from wet r/y

Question 26

Anti shimmy tyre

Answer 26

A maarstrand type

Question 27

Speed ratings for tyres are measured in

Answer 27

Mph

Question 28

The letters DDR and reinforced tread indicate

Answer 28

The tyre has a layer of fabric woven into the tread which may become visible during normal use

These are not casing chords

Question 29

Red spot/ triangle on a tyre

Answer 29

Indicates the lightest area of the tyre - put against heaviest area for balancing

Question 30

Grey/green spots on the tyres

Answer 30

Gas bui;cs up between the layers during construction - awl holes are drilled to let out gas and are signified by this colour

Question 31

Ways to reduce tyre wear

Answer 31

Taxi speeds kept to a max of 25mph

Over inflation will cause excessive wear on the crown

Under inflation will cause excessive shoulder wear