Name six units operated by hydraulics
landing gears, wing flaps, control surfaces, wing-folding mechs, bomb-bay doors, brakes
Three characteristics of hydraulics
efficiency, weight, maintenance
Two disadvantages of hydraulics
leakage, contamination
* Five components of a hydraulic jack
Reservoir, hand pump, actuating cylinder, check valves, manual bypass valve
Push, pull or total weight exerted against the total area of a particular surface and is expressed in pounds
force
Amount of force on a unit of area acted upon
pressure
The total square inches of the exposed cross-sectional area, regardless of shape, that the force of pressure is applied to
working area
State Pascal's Law
Pressure exerted on an enclosed liquid is transmitted equally and undiminished, in all directions and acts with equal force in equal areas
Formula for Force
Force = Area * Pressure
* Five components of a hydraulic system
selector valve, hydraulic lines, actuating unit, reservoir, pump [SHARP]
Additional components installed in a hydraulic system
filter, accumulator (cylindrical and spherical), check valve (automatic and manual), relief valve, pressure gauge, restricctor (one-way and two-way)
Directs the flow of fluid to the actuating unit and determines the direction in which the actuating unit will be moved
selector valve
Converts fluid energy into mechanical motion
actuating unit
Medium for transmitting the fluid from one component to another
hydraulic lines
* Draw a basic hydraulic system
...
Used to store a supply of fluid under pressure for normal and emergency operation of certain actuating units. They absorb surges and thermal expansion in the system
Accumulators (cylindrical or spherical)
Purpose of an automatic check valve
permit the flow of fluid in one direction only
Purpose of a manual check valve
permit the flow of fluid in one direction only, BUT can be manually opened to permit a free flow of fluid in both directions
How are check valves maintained?
Cleaning the lapped seating areas to prevent internal leakage and tightening fittings to prevent external leakage
Used to relieve excessive hydraulic pressure
Relief valves
Purpose of a one-way restrictor
provide restricted hydraulic fluid flow in one direction only
Purpose of a two-way restrictor
limit or meter the flow of hydraulic fluid in both directions
Reduces main system pressure to a lower subsystem pressure
pressure reducing valve