1 Title of the Invention
Test-Bench for fine tuning of hand controller used on Military Aircraft
2 Field of the Invention
The field of invention is in development of test bench for fine tuning of electronic units fitted on Military aircraft.
The invention helps in offsite tuning for the hand controller used in controlling movements of cursor/pointers on the Smart Multifunctional Display (SMD) on Military aircraft, resulting in no necessity of further tuning when Hand Controller being fitter on Aircraft.
3 Background of the Invention
Output of Hand controller fitted on the Military Aircraft for movement of cursor / pointer on SMD. It is to be fine-tuned with the equipment(s) being interfaced with it so that the control signals from the 5 way press switch (S/W) are in defined linear range.
The response / Output of the hand controller was calibrated using Smart Multifunctional Display (SMD) and adjustment in the potentiometers in the hand controller was made to adjust with the display range on SMD. The hand controller is connected to a five directional (up, down, left, right and press) switch for the various controls of marker/pointer/cursor of the SMD system in Military Aircraft.
It was a tiresome affair to fine tune the hand controller sitting in the cockpit and during the other assembly activities in progress in the nearby vicinity. Further the calibration was not an absolute affair as it was depending on the accuracy of the other interfaced equipment (SMD) and its functional performance.
In view of the above drawback of the interfacing requirement, a tuning method was to be explored to reduce the in-cockpit tuning time.

This was done by developing the methodology and test bench on which tuning of Hand Controller can be done independently and no further tuning is required after mounting on the aircraft.
Further two modifications of hand-controller are in existence and the test-bench is developed to be catered for both the modifications with single toggle switch (S5)
3.1 Prior Art
No prior art exists hence cannot be compared with any previous art
4 Brief Summary of the Invention
This invention is used to tune the Hand controller as per the specific aircraft requirement. With this test bench we are able to tune the hand-controller and position it on aircraft for satisfactory performance.
The tuning is one of the important part of servicing and mounting procedure of the hand controller in the aircraft. Testing is done by manually pushing the switch (S4) up or down or sideways.
When the switch is pressed the voltage output is to be in a specific rage as stated and is different for different aircraft.
5 Detail Description of the Drawings
FIG 1: Connection schematic for Loom
FIG 2: Schematic for the test bench FIG.3: Various views of Test bench FIG 4: (to be checked if available)
1. Volt Meter
2. AC Lamp Indicator L1
3. DC Lamp indicator L2

4. Test Sockets- 4 Nos (Y, -X, Y, -X )
5. 19 Pin connector-PL 26
6. Hand controller/19 Pin connector
7. Circuit breaker -CB2/DC 28V 3 Pin connector
8. Circuit breaker- CB1/AC 115V 6 Pin connector
9. Thumb control switch-S4

10. Zero-way toggle switch- S1, S2, S5
11. 5-way togged switch (up, down, left, right and press)
6 Detail Description of the Invention
Presently there is no test kit available for calibration of HOTAS (Hands on Throttle and Stick) Modified Hand controller that is used on DARIN II and DARIN III modified aircraft. Post Hand controller modification, the hand controller slew voltages need to be adjusted for proper usage on the aircraft.
The voltages are adjusted on the aircraft and is a tedious process and time consuming. In order to avoid this, the present test kit is designed and the hand controller voltages shall be adjusted on ground. Finally, the hand controller can be installed directly on the aircraft.
Test kit is supplied with 115 V, 400 Hz AC and 28 V DC and the Looms are connected to Aircraft test connectors and to the test kit connector PL26(5). The other connector Is connected to the HOTAS modified hand controller. Circuit breakers, CB1(8) & CB2(7) on the test kit protects the test kit for AC and DC inputs along with Switch S1(10) and S2 (10)respectively.
Switch S4(9) is provided to give access for deflections of either 'X' or 'Y\ Switch S5(10) provided to differentiate the options between Pre-MOD and

Post MOD hand controller. However, this kit is used to adjust the slew voltages of Modified hand controller.
Offset Voltages Before Adjustment
Connect the Modified Hand Controller to the test kit. Switch on the aircraft Power supply. Put the CB's CB1(8) and CB2(7) in 'IN' position. Ensure the lamp L1(2) and L2(3) glows to indicate AC and DC supply to the test kit. Put the deflection selection switch S1(10) to 'ON' position and Pre/Post Mod selection switch S5(10)to Position 2 (For Post MOD Hand controller). Without operation of the Slewing switch S/W check the offset voltage across hand controller which is displayed on the voltmeter(l).
Voltmeter(l) should read ±0.2 V. if the observed voltage is above the tolerance, adjust the hand controller offset voltage using the offset-potmeters X or Y on the hand controller respectively.
Gain Voltages Before Adjustment of X-Axis
Select switch S4(9) in position 'X' for X-axis gain voltage. Push the thumb control(S4) on the Hand controller slowly to 'RIGHT/LEFT' extreme and record the observed X-axis +ve Gain Voltage which should be +5.8 V for right gain and - 5.8 V for left gain. If the measured voltages are not within the limits, adjust the Gain Potentiometers of the Hand controller values using the X-axis Gain Potentiometers.

We Claim,
1. A test- bench for tuning of Hand Controller signal output for SMD fitted on the aircraft, comprising:
a Circuit Breaker - 2 Nos - CB1 (8) & CB2(7); a 5 way tagged switch(9)( up, down, left, right and press)-S4; a Zero way toggle switch (10)- S1, S2, S5; a Voltmeter(l);
a 19 pin connector(5) - PL 26; Indicator lamps, L1{AC)(2), L2(DC)(3); Test sockets(4)- 4 No (Y, -X, Y, -X); A Wooden box to contain the test set up; and
Looms for establishing connection between the test bench, power supplies and hand controller.
2. The test-bench for tuning of Hand Controller as claimed in claim 1, wherein the spring loaded switch, S4{9) has five way movements (up, down, left, right and press) for controlling movement of target spot/cursor/pointer on SMD (smart multifunctional Display).
3. The test-bench for tuning of Hand Controller as claimed in claim 1, wherein the test bench has mod switch, S5(10) which once activated can be used for the different modifications of hand controller. There are two mods available for one particular aircraft and tuning of both the mods can be done with the same test bench using the toggle switch for switching from one mode to another.
4. The test-bench for tuning of Hand Controller as claimed in claim 1, wherein the test bench can be used for onsite tuning and fitment of the Hand Controller in the field areas as the power supply connectors and connection are compatible to that of the aircraft maintenance requirements.