Pneumatic Systems Flashcards
What is pneumatics
Using pressurised gas to transmit force and energy
Where are pneumatics used in aircraft
Emergency source of power
Gears, flaps, brakes, landing gear (does not have to be instantaneous)
De-Icing
Pressurised environment
What are the 4 key components of a pneumatic system
Compressor
Actuator
Valve
Reservoir
Where can a compressor get its air from
A dedicated compressor
Aircraft engine/APU
External ground supply
What are the advantages of using a pneumatic system
Air is inexhaustible
Components are simple and light
Weight saving
Free from temperature problems
Little to no fire hazard
What gases are used in a pneumatic system
Air
Nitrogen
Why is compressed oxygen not used in pneumatic systems
Very big fire hazard
Expensive
No advantage over air
What are the 3 system pressures and their psi values
High - 1000-3000psi
Medium - 500-1000psi
Low - 0-500psi
Where do high pressure systems get the gas to operate the system
Metal bottles that have a charging valve and a control valve
What are medium pressure systems used to operate
Anti Icing
Cabin heating
Provides air flow for starting engines
Controlling cabin pressure
How is a medium pressure systems powered
Engine bleed air
What is an Air Service Unit (ASU)
Fitted after compressor in a circuit
Has several functions:
Filters air before it reaches the system
Regulates pressure
Lubricates pneumatic components
What are pneumatic pipes made from
Normally aluminium alloy
Low pressure systems use polyurethane pipes
What are the 2 typical control valves found in a pneumatic system
Direction control valves
Flow control valves
What are the 2 types of actuator
Single acting
Double acting
