Hydraulic Systems Introduction Flashcards
What is hydraulics?
Use of fluid pressure to transmit force.
What are the advantages of hydraulic systems?
- Less space required
- Less complex, lighter support system
- No friction or backlash
- Fewer inaccuracies
- Less weight in comparison
- Less power lost through the system
What are the principles of hydraulics based off of? Define this principle and what is equation?
- Pascal’s Law
- When a force is applied to a fluid in an enclosed container, the resulting pressure in the fluid acts equally in all directions.
- P = F/A
Explain hydraulics in a closed system
- Pressure is equal throughout the system because hydraulic fluid in the cylinders is incompressible
- Force against the piston in the larger cylinder is greater because of the larger piston area.
- Greater piston surface area equals greater force with equal pressure.
What is a common example of hydraulic system?
Aircraft brake system
What are some key properties of hydraulic fluids?
- Incompressibility
- Low viscosity
- Non-corrosiveness
- Inflammability
- Non-toxicity
- Low freezing point
- Stability
- Low volatility
- Colour
What could result if the wrong hydraulic fluid is used?
May cause hoses and seals to disintegrate which will cause the system to malfunction
What will occur if two different hydraulic fluids are mixed?
May result in gelling or coagulation which could lead to hydraulic system failure.
Do hydraulic fluids undergo some chemicals changes during normal operations?
Yes
Where can you access a Material Safety Data Sheet (MSDS) for hydraulic fluid?
MSDS Compliance Management System
What are the 8 common components of a hydraulic system?
- Reservoir
- Pumps
- Pressure regulator
- An accumulator
- Check valves
- Relief valves
- Selectors
- Actuators
What are some systems operated by hydraulics?
- Brakes
- Landing Gear
- Flight Control Surfaces
What are some components of Landing Gear (LG) Systems that use hydraulics?
- Struts - for example a shock strut, which assists in absorbing the load of the aircraft on landing.
- Actuators - to transmit fluid pressure into mechanical force
- Valves - to sequence hydraulic events
What is the key to the hydraulic system’s ability to function properly?
The ability to hold pressure.
What can lead to significantly impact hydraulic pressure?
- Loss of fluid and pressure
- Potential implications caused by the inducement of air.
What is an indication that air has entered the hydraulic system?
- Degraded system performance
- Audible knocking
- Corrosion if the air is moist.
What are some methods of hydraulic system performance monitoring?
- System pressure gauge
2. Warning lights that illuminate when system pressure varies outside of the stipulated parameters.
Without manual reversion to manipulate flight controls, how may an aircraft still be able to generate hydraulic power?
- Standby electrical pump
- Emergency hydraulic accumulators
- Engine-driven pumps
- Air-driven pump
- Ram-air turbine
What is the hydraulic reservoir?
Hydraulic fluid tank - holds the required amount hydraulic fluid
What is the hydraulic power pump?
Supplies the fluid pressure for the hydraulic system
What is the hydraulic filter?
Filters out any debris that may damage the system
What is the hydraulic pressure regulator?
Maintains a desired pressure for the system
What is the purpose of the hydraulic accumulator?
- Is a steel cylinder with floating piston that separates fluid from gas
- Supplies a reserve of pressure for the system in the way of stored energy.
What is the purpose of hydraulic non return valves?
Prevent reverse flow of hydraulic fluid
What is the purpose of a hydraulic hand pump?
Supplies fluid pressure by hand, only used in emergencies.
What is the hydraulic pressure gauge?
Displays the systems pressure and limits
What is the hydraulic relief valve?
A safety valves that limits the amount of pressure being applied to a liquid in a closed system.
What is the hydraulic selector valve?
Control the direction of movement of the actuator
What is the hydraulic actuating unit?
Converts the fluid pressure energy into mechanical force
