1. Title of the invention

Test Facility and Method to test Integrated Dynamics System (IDS) of Advanced Light Helicopter.

2. Field of invention

This invention is related to Test facility and procedure of Helicopter main Transmission System.

3. Use of invention

This invention is used to test helicopter Integrated Dynamic System and certify for flight.

4. Prior art

This method is unique. There was no previous facility available

5. Draw backs of prior art

Not applicable, as this is a new method developed for the first time.

6. Comparison between prior art and present invention

Not applicable, as this is a new method developed for the first time.

7. Aim of the invention

Aim of the invention is to improve flight safety during flight, test after manufacturing and overhauling Helicopter transmission system

8. Summary of the present invention

This test facility and method is used to test Integrated Dynamic System (IDS) employed in Advanced Light Helicopter (ALH): Integrated Dynamic System of ALH consists of mainly gears, bearings, shafts and housing. This IDS needs to be tested after assembling during manufacturing and overhaul

9. Brief description

The test facility uses a AC motor with IGBT based controller for simulation of Engine.. The facility is used carry out functional test of main gear box(IDS assembly), Cyclic test for Actuated freewheel assembly, noise test of Upper control system assembly and preservative test.

10. Statement of invention

This invented method and test facility has helped to detect problems in assembly stage thereby flight test cost could be brought down considerably.

11. Detailed description of invention

The Integrated dynamic system has the function of receiving power from two Gas turbine and provide necessary drives for Main rotor and Tail rotor. Besides driving both rotors, it has to drive accessories such as alternators for power generation, hydraulic pumps for rotor control system and lubrication pump for itself. The system employed with actuated freewheel mechanism for one Engine drive and non-actuated freewheel mechanism for other engine. actuated,,free wheel(AFW) mechanism is used helicopter for system checking! by enabling hydraulic pump and alternator. The schematic is shown below.

Major components in the IDS assembly are gears, bearings, quill shafts, Lubrication pumps, Housings. Other major assemblies are upper control system, main rotor Hub Assembly. The test facility evaluate the performance of lubrication pumps, temperature stabilization characteristics, bearing temperatures, vibration parameters etc.

A special facility has been established at HAL for the purpose. The test facility consists of ■ an IGBT controlled AC motor for simulation of engine acceleration and deceleration during start . and stop as in helicopter. A speed increasing gear box was selected for matching the.* commercially available motor speed and engine speed. The schematics of the test set up is shown below.
Following sensors were selected to measure parameters.
Pressure Sensors - 3nos
Flow sensors- 2 nos
Temperature Sensors- 8'Nbs
Metallic Chip detectors- 2Nos
Speed Sensor-1 no
Vibration sensor-1 no.

Necessary signal Conditioners were used to collect low level signals from sensors. This conditioned signals then fed to high speed analog to digital convertor via a multiplexer. The information in digital domain is then processed by dedicated software specially designed for the purpose.

The software control the speed of the motor as per predefined manner. The system increase the speed and verify all parameters are meeting requirement in steps. Once it reaches required speed of 6000 rpm it will assess temperature characteristics for a period of 60 mins. A real time display has been developed using soft panels. This soft panel has graphs, charts, dial gauges and alarm indication. If any abnormalities observed during test the system automatically shuts down with necessary annunciation. All the parameters will be recorded in every 300 milliseconds.

This recorded data can be used for further analysis in case of any abnormality. In case of satisfactory completion of test, system automatically stops test and creates on line reports which will get printed for hard copy documentation.

I Claim

1. Method to test Integrated Dynamic System to evaluate performance of lubrication system, Thermal Characteristics, Control Mechanism by the use of externally simulated speed and controls.

2. Design and Development of software to control the test facility and acquire data and analyses results and provide online decision.

3. Development of a test procedure to evaluate the IDS performance.