Hydraulic Systems Flashcards
The ____________ reduces the mechanical workload of the Pilot in the manipulation of the flight controls.
hydraulic system
Small movements of the flight controls direct hydraulic fluid at a pressure of _______ to the proper side of the power cylinder, causing the desired movement in the rotors.
1,000 psi
A power cylinder for the tail rotor control operates similarly to those for the collective and cyclic, but consists of only 1 sec powered by System __.
1
Hydraulic systems are comprised of 6 basic elements:
Fluid Reservior Pump Pressure Control Fluid Control Actuators
Incompressible and flexible. Can transmit force in any direction. Resists chemical breakdown, is non-corrosive, and provides cooling and lubrication for system components.
Fluid
Storage for a reserve supply of fluid to compensate for leakage. Allows for thermal expansion of fluid.
Reservior
Ensures the proper amount of fluid is available at the appropriate pressure. May be electrically or mechanically powered.
Pump
May be accomplished by pressure regulator valve(s) or pressure relief valve(s).
Pressure Control
Permit flow in 1 direction only.
Check valves
Protect system integrity in the event of excessive fluid temperature.
Thermal relief valves
Transform the energy of fluid flow to mechanical force.
Actuators
UH-1N main rotor cyclic and collective controls are powered by 2 separate and completely independent hydraulic systems, referred to as ______ and _______.
System 1/System 2
System 1 and 2 reservoirs are identical, _________ units which hold approximately _____ of hydraulic fluid.
- non-pressurized
- 2.5 qt
Pumps are identical in function, but operate at different speeds (due to their location on the transmission). #1: ________; #2: __________.
1: 4,300 rpm
2: 6,600 rpm
Hydraulic pumps are rated at _______
1,000 psi (± 25)
Hydraulic Pumps: ______ minimum delivery rate at normal operating rpm.
6.0 gpm
When the solenoid valve is closed (i.e., at aircraft shut down or if an individual system is deselected during flight), the _______ and/or _________ caution segment will illuminate as the system pressure drops below ____ psi.
- HYD SYS 1 and HYD SYS 2
- 650
Integrated Valve and Filter Assembly: Relief valve - will relieve hydraulic overpressure in __________ psi range.
1,100 - 1,300
Integrated Valve and Filter Assembly: ____________ - activates cockpit caution light when pressure drops below ____ psi
- Pressure switch
- 650
Integrated Valve and Filter Assembly:
____________ system shutoff valve:
1) Electrically held closed and depowered open for fail safe operation.
2) Takes electrical power to turn the system off.
Solenoid operated
Integrated Valve and Filter Assembly:
____________ shutoff valve:
1) Automatically shuts system down if pressure drops to 600 psi or below.
2) Preserves remaining hydraulic fluid in servos.
3) Automatically opens when system pressure is at or above ____ psi.
- Pressure operated
- 750
Integrated Valve and Filter Assembly:
There are __ filters for each system.
2; 1 for pressure and 1 for return fluid flow.
Integrated Valve and Filter Assembly:
They filter particles down to ___ microns.
5
Integrated Valve and Filter Assembly:
Non-electric pop-out indicators for each filter:
a) Red indicators pop at ___ psi pressure differential across filter element.
b) An electrical circuit trips a cloverleaf type indicator in the Pilot’s chin window; the indicator turns white when any of the __ filters is clogged.
c) To determine which filter is clogged, the indicators on the valve and filter assembly must be _______ checked.
- 70
- 4
- visually
__________ are cylinders incorporating a spring loaded piston.
Accumulators
Where is the electrically operated clogged filter indicator for the hydraulic systems located?
Nose compartment seen through the Pilot’s chin window.
The pressure operated shutoff valve closes at __________ psi in order to isolate an inoperative hydraulic system.
600
The appropriate HYD SYS caution panel segment will illuminate when the pressure drops below __________ psi and extinguish when pressure rises above __________ psi.
650; 750
T/F: In the event of a dual hydraulic system failure, an airspeed of approximately 70 kts will normally provide the least amount of feedback in the flight control system.
True
