AIRCRAFTS AIRCRAFTS HYDRAULIC SYSTEMHYDRAULIC SYSTEM

YASH VARDHANYASH VARDHAN09128401240912840124

INTRODUCTIONINTRODUCTION Hydraulics is based on the fact that Hydraulics is based on the fact that

liquids are incompressibleliquids are incompressible Hydraulic system is a system where Hydraulic system is a system where

liquid under pressure is used to liquid under pressure is used to transmit energytransmit energy

In it a hydraulic pump converts In it a hydraulic pump converts mechanical power to hydraulic powermechanical power to hydraulic power

An actuating cylinder converts An actuating cylinder converts hydraulic power to mechanical hydraulic power to mechanical power.power.

A SIMPLE HYDRAULIC SYSTEMA SIMPLE HYDRAULIC SYSTEM

DEVICES USING HYDRAULIC DEVICES USING HYDRAULIC SYSTEMS IN AIRCRAFTSSYSTEMS IN AIRCRAFTS

Gun turretsGun turrets Auto pilotAuto pilot Shock absorption systemsShock absorption systems Dive, landing, speed and flap brakesDive, landing, speed and flap brakes Bomb bay doors Bomb bay doors Doors and hatchwaysDoors and hatchways Landing gears, wing flaps, etc…Landing gears, wing flaps, etc…

PRINCIPLES OF OPERATIONPRINCIPLES OF OPERATION Governed by Pascal’s lawGoverned by Pascal’s law The oil is in contact with The oil is in contact with

both sides of the piston both sides of the piston head but at different head but at different pressures. High pressure pressures. High pressure oil may be pumped into oil may be pumped into either side of the piston either side of the piston head. head.

The selector valve The selector valve determines to which side determines to which side of the actuating cylinder of the actuating cylinder the high pressure oil (red the high pressure oil (red colored side) is sent. colored side) is sent.

PARTS OF THE POWER SYSTEMPARTS OF THE POWER SYSTEM

RESERVOIRRESERVOIR ACCUMULATORACCUMULATOR FILTERFILTER POWER PUMPPOWER PUMP SYSTEM RELIEF VALVE SYSTEM RELIEF VALVE PRESSURE REGULATORPRESSURE REGULATOR

POWER SYSTEMPOWER SYSTEM

RESERVOIRRESERVOIR

FUNCTIONSFUNCTIONS Holds reserve supply oil to account for Holds reserve supply oil to account for

normal leakage, emergency supply of oil, normal leakage, emergency supply of oil, volume changes, thermal contraction of volume changes, thermal contraction of oil,oil,

Provides pressure head on the pump, a Provides pressure head on the pump, a place to remove air or foam from liquid, place to remove air or foam from liquid, air space for expansion of the oil due to air space for expansion of the oil due to temperature changes temperature changes

etcetc

RESERVOIRRESERVOIR

CONSTRUCTIONCONSTRUCTION Material: 5052 aluminiumMaterial: 5052 aluminium Size: takes into account all oil Size: takes into account all oil

volumes in operational volumes in operational requirements, thermal expansion, requirements, thermal expansion,

leakage, etc.leakage, etc. Shape: domed cylindrical shape, Shape: domed cylindrical shape,

due to ease of construction & due to ease of construction & mounting mounting

ACCUMULATORSACCUMULATORS

PRINCIPLEPRINCIPLE Gas valve lets in Gas valve lets in

compressed gas at ½ compressed gas at ½ system pressuresystem pressure

Diaphragm pops up & Diaphragm pops up & oil is sent through oil is sent through systemsystem

When system When system pressure>accumulator pressure>accumulator pressure, diaphragm pressure, diaphragm deploys deploys

ACCUMULATORSACCUMULATORS

USESUSES Absorbs the shocks due to rapid pressure Absorbs the shocks due to rapid pressure

variations in a hydraulic system variations in a hydraulic system Helps maintain a constant pressure within Helps maintain a constant pressure within

the hydraulic system the hydraulic system Helps the hydraulic pump under peak Helps the hydraulic pump under peak

pressure loads pressure loads It is an emergency source of power It is an emergency source of power Spherical shape is preferred for Spherical shape is preferred for

accumulators accumulators

POWER PUMPSPOWER PUMPS

FUNCTIONFUNCTION Is to change mechanical horsepower to Is to change mechanical horsepower to

hydraulic horsepower hydraulic horsepower TYPESTYPES Gear pumps: move fluid based upon the Gear pumps: move fluid based upon the

number of gear teeth and the volume number of gear teeth and the volume spacing between gear teeth.spacing between gear teeth.

Piston pumps: move fluid by pushing it Piston pumps: move fluid by pushing it through the motion of the pistons within through the motion of the pistons within the pump the pump

POWER PUMPSPOWER PUMPS

PRINCIPLES OF GEAR PRINCIPLES OF GEAR PUMPSPUMPS

The liquid from the The liquid from the reservoir is pushed reservoir is pushed between the gear between the gear teeth. teeth.

The oil is moved The oil is moved around to the other around to the other side by the action of side by the action of the drive gear itself the drive gear itself and sent through the and sent through the pressure line. pressure line.

POWER PUMPSPOWER PUMPS

PRINCIPLES OF PRINCIPLES OF RECIPROCATING RECIPROCATING PISTON PUMPPISTON PUMP

As the cylinder block As the cylinder block rotates, space rotates, space between the block and between the block and the pistons increase, the pistons increase, letting in more oil. letting in more oil.

As the block rotates As the block rotates from bottom dead from bottom dead center, the reverse center, the reverse occurs and the pistons occurs and the pistons push oil out through push oil out through the outlet the outlet

SYSTEM RELIEF VALVESYSTEM RELIEF VALVE

PRINCIPLEPRINCIPLE The adjustment The adjustment

screw is set for a screw is set for a certain pressure certain pressure value P2. value P2.

When the pressure When the pressure increases, the increases, the poppet will move poppet will move up, forcing the up, forcing the excess liquid inexcess liquid in

Douglass Pressure RegulatorDouglass Pressure Regulator

high pressure oil from high pressure oil from the power pump the power pump opens valve C and opens valve C and also act on piston A also act on piston A

piston A pushes Ball B piston A pushes Ball B off seat D, the oil goes off seat D, the oil goes through passage D through passage D into the center into the center chamber back to the chamber back to the reservoir. reservoir.

HAND PUMPSHAND PUMPS

Selector Valves Selector Valves Position (1) is the position of the selector valve, Position (1) is the position of the selector valve,

for example, upon the extension of the landing for example, upon the extension of the landing gear or the lowering of flaps.gear or the lowering of flaps.

Position (2) is the position of the selector valve Position (2) is the position of the selector valve upon retraction of the landing gear or the raising upon retraction of the landing gear or the raising of the flaps of the flaps

FLOW EQUALISERFLOW EQUALISER

If wing air loads on one If wing air loads on one wing are greater than on wing are greater than on other, during wing sweep other, during wing sweep back or sweep forward, back or sweep forward, motion occurs unevenly.motion occurs unevenly.

To synchronize wing sweep To synchronize wing sweep back or sweep forward flow back or sweep forward flow equaliser usedequaliser used

flow equalizer is made up of flow equalizer is made up of two power pumps placed two power pumps placed side by side in which the side by side in which the drive gears of both pumps drive gears of both pumps are connected are connected

ACTUATION CYLINDERACTUATION CYLINDER

The function is to take The function is to take the pressure & hydraulic the pressure & hydraulic fluid flow & change them fluid flow & change them into linear or rotary into linear or rotary motion. motion.

Single piston double rod Single piston double rod is an equal displacement is an equal displacement cylinder used in aileron cylinder used in aileron system or automatic system or automatic guidance system guidance system

Double piston-double rod Double piston-double rod actuating cylinder used actuating cylinder used in bomb bay doors in bomb bay doors

ADVANTAGESADVANTAGES It is lighter in weight than alternate existing It is lighter in weight than alternate existing

systems. systems. It is dead beat, that is, there is an absence of It is dead beat, that is, there is an absence of

sloppiness in its response to demands placed on sloppiness in its response to demands placed on the system. the system.

It is reliable; either it works or doesn't. It is reliable; either it works or doesn't. It can be easily maintained. It can be easily maintained. It is not a shock hazard; it is not much of a fire It is not a shock hazard; it is not much of a fire

hazard. hazard. It can develop practically unlimited force or It can develop practically unlimited force or

torque. torque.

CONCLUSIONCONCLUSION

Hydraulic systems determine flight Hydraulic systems determine flight worthiness, usability and reliability.worthiness, usability and reliability.