A

PAPER PRESENTATIONON

“AIRCRAFT HYDRAULIC SYSTEM” Presented By

THORAT SANDIP

SHINDE GANESH

DEPATMENT OF MECHANICAL

ENGINEERING

AMRUTVAHINI COLLEGE OF ENGINEERING, AMRUTNAGAR,TAL –SANGAMNER, DIST–AHMEDNAGAR, (M.S)

INDIA-422608

UNIVERSITY OF PUNE

(2016-2017)

This presentation first describes the development and application of aircraft hydraulic systems with emphasis on the basic structure of hydraulic systems, a typical hydraulic system in the Boeing family of aircraft, and a typical hydraulic system in the Airbus family of aircraft. Then, basic parameters of aircraft hydraulic systems, including hydraulic fluid, hydraulic pressure, fluid temperature, fluid flow rate, hydraulic pipes, and pressure pulsation, are provided. Afterward, the main components of aircraft hydraulic systems are introduced, including aircraft hydraulic pumps (engine-driven pump and AC motor-driven pump), power transfer units, priority valves, control valves, check valves, hydraulic accumulators, hydraulic filters, hydraulic reservoirs, fluid cooling systems, hydraulic actuators, and redundant hydraulic actuators. Finally, the proof test of an aircraft hydraulic system is presented and discussed, with special attention to the hydraulic system testing process.

Abstract

Presented byThorat Sandip Shinde Ganesh

INTRODUCTION Hydraulics is based on the fact that liquids are incompressible Hydraulic system is a system where liquid under pressure is used to

transmit energy In it a hydraulic pump converts mechanical power to hydraulic power An actuating cylinder converts hydraulic power to mechanical power.

A SIMPLE HYDRAULIC SYSTEM

DEVICES USING HYDRAULIC SYSTEMS IN AIRCRAFTS

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

PRINCIPLES OF OPERATION

Governed by Pascal’s law The oil is in contact with both

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

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

PARTS OF THE POWER SYSTEM RESERVOIR ACCUMULATOR FILTER POWER PUMP SYSTEM RELIEF VALVE PRESSURE REGULATOR

POWER SYSTEM

RESERVOIR

FUNCTIONS Holds reserve supply oil to account for normal

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

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

etc

ACCUMULATORS

PRINCIPLE Gas valve lets in

compressed gas at ½ system pressure

Diaphragm pops up & oil is sent through system

When system pressure>accumulator pressure, diaphragm deploys

ACCUMULATORS

USES Absorbs the shocks due to rapid pressure

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

hydraulic system Helps the hydraulic pump under peak

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

POWER PUMPS

FUNCTION Is to change mechanical horsepower to

hydraulic horsepower TYPES Gear pumps: move fluid based upon the

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

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

POWER PUMPS

PRINCIPLES OF GEAR PUMPS

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

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

POWER PUMPS

PRINCIPLES OF RECIPROCATING PISTON PUMP

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

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

HAND PUMPS

Selector Valves

Position (1) is the position of the selector valve, for example, upon the extension of the landing gear or the lowering of flaps.

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

FLOW EQUALISER

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

To synchronize wing sweep back or sweep forward flow equalizer used

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

ACTUATION CYLINDER

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

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

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

ADVANTAGES

It is lighter in weight than alternate existing systems. It is dead beat, that is, there is an absence of

sloppiness in its response to demands placed on the system.

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

hazard. It can develop practically unlimited force or torque.

CONCLUSION

Hydraulic systems determine flight worthiness, usability and reliability.

References

•http://aerospace.eaton.com/news.asp?articledate=06/01/03&NewsCommand=ViewMonth

•http://www.tpub.com/content/aviation/14018/css/14018_178.html Air Force Research Laboratoryhttp://www.afrlhorizons.com/Briefs/0006/VA9902www.hydraulic equipment.com

ANY QUESTIONS?