SUMMER TRAINING AT HINDUSTAN

AERONAUTICS LIMITEDSUBMITTED BY-

TANUSH TRIPATHI(1309120103)SUBMITTED TO-

Mrs. DIVYA CHANDRA

AIRCRAFT HYDRAULIC SYSTEMS Hydraulic systems are not new to aviation .In earlier aircrafts hydraulic systems

are used in brake systems. As aircraft became more and more advanced, newer systems with hydraulic power were developed.

Today the operation of landing gears, flaps, flight control surfaces and brakes is largely accomplished with hydraulic power systems.

Hydraulic systems have many advantages as power sources for operating various aircraft units

Hydraulic systems are light weight Installation ,inspection of hydraulic systems is easy. Hydraulic systems are almost 100 percent efficient ,with only negligible loss due to

fluid friction.

INTRODUCTION

HS-748 aircraft was started from 1980 for Indian Air Force.45 aircraft have been overhauled till March 96. In addition to this, refurnishing, Cat-B and minor repairs of HS-748 aircraft are also being carried out. As the aircraft of IAF are in healthy condition, it has been decided to upgrade the control system, Navigation System and Auto-Pilot Units etc with latest technology for getting better utilization of aircraft to the customer. In the same line MOD-S Transponder also has been fitted to have better communication.

Max take off wt. :- 43500LBS Max landing off wt. :- 41500LBS Max zero fuel wt. :- 36300LBS Max crusing speed :- 245knots Crusing height :- 20000m

AVRO(HS-748):-

HS-748 AVRO AIRCRAFT The HS 748 Hawker Siddeley is a medium sized turboprop airliner designed by

British firm Avro. The aircraft uses two Rolls Royce turboprop engines. This aircraft is also license produced in India by Hindustan Aeronautics Limited

(HAL-748). Hawker Siddeley also used the HS-748 for their HS 780 Andover- a transport

aircraft built for Royal Air Force. HAL built 89 Avro aircrafts in India ,72 for the Indian Air Force and 17 for

Indian Airlines Corporation. Production of HAL -748 ended in1988. HS 748 today are used as passenger aircrafts , fighter aircrafts, as well as for bulk

fuel hauler.

Crew: Three (two pilots + one passenger attendant) Capacity: 40–58 passengers Payload: 5,136 kg Length:  20.42 m Wingspan: 31.23 m Height:  7.57 m Wing area:  77 m² Empty Weight: 12,327 kg Max. Takeoff weight:  21,092 kg Cruise speed:  452 km/h Range:  1,715 km (with max payload) Service ceiling: 7,620 m Wing Load: 274 kg/m² Power/mass: 0.161 kW/kg

General characteristics:-

The HAL was founded on 23rd December 1940 as Hindustan Aircraft Pvt limited at Bangalore by late Walchand Hirachaand in association with government of Mysore for the aircraft making in India.

The organization and the equipment's for the factory at Bangalore was set up by Intercontinental Aircraft Corporation of New York.

In august 1963 Aeronautics India Limited was incorporated as a company wholly owned by the government of India to undertake the manufacturing of MIG-21 Aircraft under license.

In 1st October 1964 ,the merging of Hindustan Aircraft Pvt Ltd and Aeronautics India Limited led to formation of Hindustan Aeronautics Limited(HAL)

HISTORY OF HAL

The division was set up in 1960 to manufacture HS-748, but with passage of time ,the division now manufactures varieties of aircrafts , structural assemblies, paints, and detailed part manufacturing of various components.

Current Activities of TAD Kanpur:- Manufacturing of HAL Dornier 228 Aircraft Servicing and overhaul of AVRO Aircraft Servicing of engines of Unmanned aerial vehicle (UAV) There are 8 hangars in the factory Some of the other facilities at TAD Kanpur :- Machining Facilities Composites ,Plastics Sheet Metal, Welding Quality Control Facilities

TRANSPORT AVIATION DEPARTMENT(TAD) HAL KANPUR

HAL is the largest defence PSU among 9 defence PSU’s in India today. HAL is the only company in the world which manufactures both frames as well as

engines of the aircraft. More than 3800 aircrafts and 4500 engines have been produced by HAL. HAL is a navratna company since 2007. HAL has 20 production and 10 R&D centers in India.

WHAT IS HAL TODAY

The Hydraulic Power System comprises of a main system supplied by engine driven pumps , and an auxiliary system provided with a hand pump.

The auxiliary system supplies pressure for ground servicing and for use in emergency if the main system fails.

In an aircraft , the operation of Landing Gears ,Doors, Flaps , undercarriage, steering ,wiper and Brakes is largely accomplished with Hydraulic Systems .

The Hydraulic systems in an aircraft are based on pascal’s law and Bernoulli's principle. Different components of hydraulic system in an aircraft are:- Reservoir Accumulator Actuators Filter Engine driven Pump(EDP) Hand Pump System Relief Valve Pressure Regulator Cut-out Valve

Hydraulic System

RESERVOIR The function of reservoir is to hold reserve supply oil to account for

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

Reservoir also provides pressure head on the pump. Reservoirs are usually made of aluminum.

ACCUMULATOR The function of accumulators is to absorb the shocks due to rapid

pressure variations in a hydraulic system. It also helps to maintain constant pressure within hydraulic system

ACTUATORS An actuator is a mechanical device that takes energy & converts it

to a desirable form for usage or application. In hydraulic systems the actuator converts Hydraylic energy into

mechanical systems

The engine driven pump is the pump that provides the primary hydraulic power in many aircrafts today such as Boeing ,Airbus ,Sukoi and other passenger aircrafts and fighter jets.

The typical EDP configuration is a pressure-compensated, variable displacement axial piston pump capable of varying the volume of fluid delivered to maintain hydraulic system pressure.

The Engine driven pump is connected directly to the turboprop engines.

As the barrel rotates, the pistons reciprocate within their bores, taking in and discharging fluid through a stationary valve

The hanger is supported by bearings that permit angular rotation about an axis perpendicular to the cylinder barrel centerline. By changing the angle of the hanger, the length of the piston stroke varies, resulting in a change in pump displacement.

ENGINE DRIVEN PUMP(EDP)

ENGINE DRIVEN PUMP

The hand pump was used as primary pump in older aircrafts. Nowadays the hand pump is used in aircrafts either as a emergency pump(if

primary pump fails , then this pump can be used) or for testing purposes. Several types of hand pumps are used: single action, double

action, and rotary , the double action pumps are mostly used since they are highly efficient.

HAND PUMP

The Hydraulic fluid , from reservoir goes into the engine driven pump.The reservoir is connected to EDP through a high pressure relief valve.The maximum pressure that can be sustained by relief valve is 3300 psi.

The EDP is connected to a cut out valve which is connected to the Actuators of aircraft system.

When the aircraft is on the ground ,EDP is used and pressure is increased using EDP.

But when the aircraft is in flying mode, the EDP is disconnected from the aircraft using a cutout valve.

The cutout valve is further connected to tank using a venting valve.

WORKING OF HYDRAULIC SYSTEM

It is lighter in weight than alternate existing systems.

It is reliable . 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. This is highly efficient systems because of

negligible friction losses.

ADVANTAGES OF HYDRAULIC SYSTEM

SNAGS REMEDIES1. Services fail to respond to

engine driven pump or hand pump

Ensure sufficient oil in system. If oil is sufficient then replace the cut out valve

2. System fails to build up pressure when powered by hand pump

Hand pump should be checked for its proper functioning.

3. Main accumulator gas pressure is high

Check the accumulator gas pressure .Release some gas and reduce the pressure of accumulator

4. Main accumulator gas pressure is low

Release gas pressure and inflate the accumulators to correct pressure.

5. System pressure indicator gives false reading

Relay and transmitter units may be faulty and should be replaced.

6. Hammering noise from system as pressure nears cut out figure

Install a new cut out valve.

GENERAL SNAGS AND REMEDIAL MEASURES

Apart from hydraulic system of Avro aircraft as a part of our project, I have also studied about Dornier -228 Aircraft ,the only difference between two systems is that the Engine Driven Pump of Dornier aircrafts is equipped with a motor. The EDP of Dornier aircrafts works all the time i.e when the aircraft is on the ground as well as it is flying.

Hydraulic systems ,in general are now used in most of the components of the aircrafts. Due to its high efficiency and low frictional losses ,it has replaced most of mechanical systems.

Nowadays , hydraulic systems integrated with electrical systems are used nowadays ,equipped with micro-processors and micro-controllers.

CONCLUSION