FORM 2
THE PATENT ACT 1970
(39 OF 1970)
&
The Patent Rules, 2003
PROVISIONAL/COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION: Design and fabrication of multifunctional test rig for aircraft
landing gear assembly.
2. APPLICANT(S)
(a) NAME: Hindustan Aeronautics Limited
(b) NATIONALITY: INDIAN
(c) ADDRESS
Hindustan Aeronautics Limited, Ojhar, Nashik, Maharashtra, India

3. PREAMBLE TO THE DESCRIPTION
PROVISIONAL
COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.
4. DESCRIPTION (Description shall start from next page.)
Refer Annexure-1
5. CLAIMS (not applicable for provisional specification. Claims should start with the preamble—"I/We Claim" on separate page.) Refer Annexure-ll
6. DATE AND SIGNATURE (to be given at the end of last page of specification)
7. ABSTRACT OF THE INVENTION (to be given along with complete specification on separate page)-Refer Annexure-lll
Note: - * Repeat boxes in case of more than one entry.
* To be signed by the applicant(s) or by authorized registered patent agent otherwise where mentioned.
* Name of the inventor and applicant should be given in full, family name in the beginning.
*Complete address of the inventor and applicant should be given stating the postal index no./code, state
and country.
*Strike out the column which is/are not applicable.

Complete Specification Of
Development of multifunctional test rig for Fighter
aircraft Landing Gear Assembly

1. Title of the invention
Development of multifunctional test rig for fighter aircraft landing gear assembly.
2. Field of invention:
The invention relates to testing of fighter Aircraft landing Gear Assembly.
3. Background of invention:
The purpose of landing gear in an aircraft is to provide a suspension system during taxi, takeoff and landing. It is design to absorb and dissipate the kinetic energy of landing impact load, transmit to airframe. TO supply fighter aircraft landing gear on time this invention works effectively by reducing cycle time of testing parameters. Testing of Fighter aircraft landing gear involves various test parameters which are essentials for proving its performance on aircraft. This includes following test parameters,
1. Oil filling inside landing gear.
2. Oleo pneumatic compression test.
3. Air bubble removal process.
4. Angle checking test.
5. Leakage test.
6. Potentiometer check.
7. Self-centring check
8. Micro switch check.
The above test require different setup which is time consuming and require more manpower involve in single unit testing which is wasting of man-hours. In order to minimise cycle time this invention help us to boost our productivity.

3.1 Prior art
The main object of invention is to provide a multifunctional test rig for fighter aircraft landing gear assembly in minimum efforts thus reducing down time of LRUS.
Landing gear system is important parameter for any type of aircraft whether it is fighter or any commercial aircraft. In case of fighter aircraft landing gear due to less space and more speed it is very critical process to design as per requirement. The whole weight of aircraft is balanced by landing gear. Thus assembly and testing of fighter aircraft landing gear important processes which need to do analysis through systematic processes. As it provide suspension during taxy, take-off and landing testing parameter is very important to do analysis of function ability as per accepted test procedure specified by design agency.
By considering of above criticality sometimes landing gear received as an AOG (aircraft on ground), condition, overhaul and manufacturing. It is mandatory to check functinability and to deliver such item on time to avoid supply of aircraft delivery to customer is concern. From overhaul to fit for aircraft processes it is time consuming activity. Before invention our test procedure was manual base, and these were required more than one person to do, resulting into loss of man hours and time for delivering final product. New system is automated which works on mechatronics and only one person can performed testing operation thus saving of man hours and ultimately on time delivery of product.
4. Brief summary of the present invention
To address the above problem a special test rig is designed. In this invention a new multifunctional test rig is fabricated and used for landing gear convenience. This invention is a unit of test rig which works in multifunctional way .This involves setup for oleo pneumatic test, Micro switch test, Angle checking, leak check, potentiometer check in single unit.
This multifunctional test rig consists of

1. Pressure gauges
2. Pump
3. Safety valve
4. Non return valve
5. Hand pump
6. Power switch indicator.
7. Continuity for micro switch
8. Pipe lines
9. Microcontroller
10. Selector valve
11. Relief valve
12. Pneumatic valve
13. Switch
14. Main power supply switch.
The Main purpose of mentioned test rig is to test aircraft landing gear in one set up. Once the oil filling is completed without air bubble inside landing gear of fighter aircraft the landing gear is to be tested further as per accepted test procedure(ATP) specified by design agency.
There are various test involve as mentioned above.
1. Self-centring test-
This test related to pneumatic system. Here landing gear has to turn to specified degree to LH and RH position and pneumatic pressure has to release from invention unit and thus landing gear has to come in central axis with specified pressure mentioned in ATP.This test has to repeat until pressure require to complete this test within mentioned limit get satisfactory results.
2. Potentiometer check-
This invention involves microcontroller which shows potentiometer values which are programmed through specified software require for particular landing gear

testing specified by design agency. Potentiometer defines resistance values noted by pilot.
3. Angle checking test-
This invention involve microcontroller which shows angle values which are programmed through specified software require for particular landing gear testing specified by design agency. Angle specified in landing gear is important parameter to define self-centring test and internal cam alignment confirmation.
4. Micro switch test /limit switch -
Mentioned invention involve micro switch continuity arrangement specified by design agency. This continuity shows weight on wheel switch indication to particular landing gear under load condition.
5. Leakage test-
Mentioned invention has arrangement of hydraulic pump system and can
developed a pressure of 100 kg/cm2, this helps to check leakage in landing gear
steering cylinder. This test can be done simultaneously while performing other test
in landing gear.
All the above mentioned tests are actuated in single test unit to minimise changeover and setup time.

4. Detailed Description Of Drawings: Figure 1:
The present invention is multitasking test rig can performed different tests involve in particular fighter aircraft landing gear. This invention involved four stages of design procedure.
1. Structure
2. Hydraulic system
3. Pneumatic system
4. Electrical/Electronic system.
A. During hydraulic testing of fighter aircraft landing gear assembly, hydraulic
pump (2) from hydraulic tank (1)supply hydraulic oil , it passes through oil filter
(3) and non-return valve (NRV)(4). Function of filter is to clean the oil and to
maintain the require class of hydraulic oil whereas non return valve (4)
restricted the reverse flow of hydraulic oil to tank. From NRV it transfer to safety
valve (5), in case if pressure of hydraulic oil exceeds, the oil flows to hydraulic
tank. During hydraulic test pressure can be regulate by pressure valve (6)
through NRV (7) it flows to work output through line 1 and Iine2 through selector
valve (9). The pressure indication require for this is through hydraulic pressure
gauge (8).Line 1 a line 2 and relief can be operate by selector valve (9). After
relief hydraulic oil flows to hydraulic tank (1).
The hydraulic system can be operate by hand pump (10). With the help of hand pump (10) pressure directly supplied to line 1 and line 2 through selector valve (9) and in this case relief valve can also operate after which hydraulic oil released to hydraulic tank (1). Circuit diagram figure 1 shows how hydraulic system works in particular invention.
Figure 2:
B. During pneumatic testing of fighter aircraft landing gear assembly Nitrogen gas
released from Nitrogen cylinder tank (17) passes through tank pressure valve

(12). It can be regulate through pressure control valve (16). There is provision of tank pressure gauge (13) display between tank pressure valve (12) and pressure control valve (16).Nitrogen pressure can be supplied to system directly. This pressure can be monitored through system pressure Nitrogen gauge (14).After completion of Nitrogen test there is provision of Nitrogen gas drain valve (15) or pressure relief valve (15). Nitrogen from system pressure performed operation like self-centring test and charging procedure. Circuit diagram figure 2 shows how pneumatic system works in particular invention.

5. DETAILED DESCRIPTION OF INVENTION
The main object of invention is to provide a multifunctional test rig for fighter aircraft landing gear assembly in minimum efforts thus reducing down time of LRUS.
Landing gear system is important parameter for any type of aircraft whether it is fighter or any commercial aircraft. In case of fighter aircraft landing gear due to less space and more speed it is very critical process to design as per requirement. The whole weight of aircraft is balanced by landing gear. Thus assembly and testing of fighter aircraft landing gear important processes which need to do analysis through systematic processes. As it provide suspension during taxy, take-off and landing testing parameter is very important to do analysis of function ability as per accepted test procedure specified by design agency.
By considering of above criticality sometimes landing gear received as an AOG (aircraft on ground), condition, overhaul and manufacturing. It is mandatory to check functinability and to deliver such item on time to avoid supply of aircraft delivery to customer is concern. From overhaul to fit for aircraft processes it is time consuming activity.
Invention of fighter aircraft landing gear test rig minimise setup and cycle time for testing to avoid delay in delivery of landing gear. Before invention there were disadvantages of testing procedure like
A. More manpower requirement
B. Changeover time consumption
C. Set up time consumption
D. Fine observation of reading
To overcome above difficulties, this invention works more sophisticated manner. Design and manufacturing of this invention consists of four stages.
a. Structural activity
b. Hydraulic system

c. Pneumatic system
d. Electrical/Electronic system.
Structure of this invention is made up of metallic frame welded from all the corners. Structure is designed such a way to withstand weight oil tank, pump and vibration created by pump while running.
Hydraulic system consists of
A. Antirust hydraulic pipelines
B. Metallic Oil tank
C. Safety valve
D. Non return valve (NRV)
E. Selector valve
F. Hydraulic pump
G. Regulatory valve
H. Hydraulic gauges
Hydraulic pipelines made up of metallic antirust material and can withstand pressure up to 300 kg/cm2. It is tested as per the requirement. These all pipelines are connected through different metallic elbows and adaptors.
During hydraulic testing of fighter aircraft landing gear assembly , hydraulic pump (2) from hydraulic tank (1)supply hydraulic oil , it passes through oil filter (3) and non-return valve (NRV)(4). Function of filter is to clean the oil and to maintain the require class of hydraulic oil whereas non return valve (4) restricted the reverse flow of hydraulic oil to tank. From NRV it transfer to safety valve (5), in case if pressure of hydraulic oil exceeds, the oil flows to hydraulic tank. During hydraulic test pressure can be regulate by pressure valve (6) through NRV (7) it flows to work output through line 1 and Iine2 through selector valve (9). The pressure indication require for this is through hydraulic pressure gauge (8).Line 1 a line 2 and relief can be operate by selector valve (9). After relief hydraulic oil flows to hydraulic tank (1).

The hydraulic system can be operate by hand pump (10). With the help of hand pump (10) pressure directly supplied to line 1 and line 2 through selector valve (9) and in this case relief valve can also operate after which hydraulic oil released to hydraulic tank (1).
Pneumatic system consists of
A. Gas cylinder
B. Antirust pneumatic pipelines
C. Pneumatic valves
D. Pneumatic gauges
E. Regulatory valve
During pneumatic testing of fighter aircraft landing gear assembly, Nitrogen gas released from Nitrogen cylinder tank (17) passes through tank pressure valve (12). It can be regulate through pressure control valve (16). There is provision of tank pressure gauge (13) display between tank pressure valve (12) and pressure control valve (16).Nitrogen pressure can be supplied to system directly. This pressure can be monitored through system pressure Nitrogen gauge (14).After completion of Nitrogen test there is provision of Nitrogen gas drain valve (15) or pressure relief valve (15). Nitrogen from system pressure performed operation like self-centering test and charging procedure.
Electrical /Electronic system consist of
A. Microcontroller for Angel checking device.
B. Microcontroller for potentiometer check
C. Micro switch/ limit switch continuity.
D. Power supply switch for electrical/electronics unit.
Potentiometer of aircraft landing gear is connected to Microcontroller 1 and microcontroller 2, when landing gear rotates to LH and RH side from its central axis microcontroller reads values which in turns output shows degree display (18) and

resistance display (20). This all connection runs of 5 volt DC supply. This invention works on mechatronics principle as per circuit diagram.
When fighter aircraft landing gear assembly is ready for testing there are important test parameter need to check and this invention helps to achieve all test mechatronically as mentioned below.
1. Self-centring test —
This test related to pneumatic system. Here landing gear has to turn to specified degree to LH and RH position from its centre axis and pneumatic pressure has to release from invention unit and thus landing gear has to come in central axis with specified pressure mentioned in ATP.This test has to repeat until pressure require to complete this test within mentioned limit get satisfactory results. In this case self-centring pressure can be observed by digital pressure gauge and fine tuning of angle displacement digitally can be noted simultaneously. With the help of microcontroller it is connected through pinion arrangement which mechanical arrangement is converted to electronics display of angle of landing gear.
2. Potentiometer check-
This invention involves microcontroller which shows potentiometer values which are programmed through specified software require for particular landing gear testing specified by design agency. Potentiometer defines resistance values noted by pilot. With the help of microcontroller it is connected through pinion arrangement which mechanical arrangement is converted to electronics display of resistance values through potentiometer of landing gear and thus fine tuning of values can be observed simultaneously.
3. Angle checking test-
This invention involve microcontroller which shows angle values which are programmed through specified software require for particular landing gear testing specified by design agency. Angle specified in landing gear is important parameter to define self-centring test and internal cam alignment confirmation. With the help

of microcontroller it is connected through pinion arrangement which mechanical arrangement is converted to electronics display of angle of landing gear.
4. Micro switch test /limit switch -
Mentioned invention involve micro switch continuity arrangement specified by design agency. This continuity shows weight on wheel switch indication to particular landing gear under load condition. Here mechanical movement of micro switch is converted to LED display of indication specified by design agency.
5. Leakage test-
Mentioned invention has arrangement of hydraulic pump system and can developed a pressure of 100 kg/cm2, this helps to check leakage in landing gear steering cylinder. This test can be done simultaneously while performing other test in landing gear.
All the above mentioned tests are actuated in single test unit to minimise changeover and setup time.
In view of the above invention, all systems are working together like mechatronics hence it is single multifunctional unit for fighter aircraft landing gear assembly.

I/We Claim:
1. Multifunctional test rig for fighter aircraft landing gear assembly comprises of
A. Oil tank (1) which utilize for storing hydraulic oil required for the
system.
B. Hydraulic pump (2) to generate required pressure for the system.
C. Filter (3) to filter and clean supply of hydraulic oil to the system.
D. Non return valve (3) to restrict the flow of hydraulic oil.
E. Safety valve (5) to protect the system from exceed pressure.
F. Pressure valve (6) to adjust the pressure of the system.
G. Pressure gauge (8) to indicate pressure of the system.
H. Selector valve (9) to distribute the pressure for different line.
I. Hand pump (10) to supply pressure to the system manually.
J. Digital pressure gauge (14) to indicate pneumatic pressure.
K. Pneumatic valve (16) to regulate pneumatic pressure.
L. Valves (12) and (15) to regulate the pressure.
M. Microcontroller digital display (18) for angle indication.
N. Microcontroller digital display (20) for potentiometer reading indication.
O. Led indicators (17) for micro switch indication.
P. Switch (19) for power supply to microcontroller and LED micro switch display.

2. Multifunctional test rig mentioned claim in claim 1, oil tank capacity ranging from 30 to 50 lit.
3. Multifunctional test rig mentioned claim in claim 1, Hydraulic pump ranging from 2.5 HP to 5 HP
4. Multifunctional test rie mentioned claim in claim 1, Filter ranging; from
5. Multifunctional test rig mentioned in claim in claim 1, non-return valve (NRV) for pressure ranging from 200 to 300 kg/cm2
6. Multifunctional test rig mentioned claim in claim 1, safety valve ranging from 200 to 300kg/cm2.
7. Multifunctional test rig mentioned claim in claim 1, pressure valve ranging from 200 to 300kg/cm2.
8. Multifunctional test rig mentioned claim in claim 1, pressure gauges ranging from 200to 300kg/cm2.
9. Multifunctional test rig mentioned claim in claim 1, selector valve ranging from 200 to 300kg/cm2.
10.Multifunctional test rig mentioned claim in claim 1, digital pressure gauge ranging from 50 to 100 kg/cm2 and pneumatic valve ranging from 100 kg/cm2 to 200 kg/cm2