Vipergear Force Sensor Installation Guide


The Viper Gear Force Sensor (VFS) functions through the use of strain gauges, which measure the amount of strain or deflection of an object when force is applied.  Strain gauges are sensitive in nature.  You should avoid touching or handling any of the wiring of the strain gauges or the strain gauges as much as possible. 


The VFS was developed to work with the Thrustmaster® HOTAS Cougar.  We are working on integrating it with newer systems, but as of this writing, it is not capable of functioning with any other side stick controller.  The HOTAS Cougar is no longer in production, so be sure to source a used one prior to purchasing this item.  Common areas to find them are eBay®, Facebook® Marketplace, or any other local online marketplace where second-hand items are sold. 


The VFS is constructed to work with the original HOTAS Cougar PCB, and will work with the default HOTAS Cougar software, firmware, and drivers supplied by Thrustmaster. 


The following is a guide for how to replace the factory Thrustmaster HOTAS Cougar gimbals with the VFS.  Installation is your responsibility, and Invictus Cockpit Systems assumes no liability for the installation process.  Please note that the photos included are from previous versions of the VFS and may not accurately represent current parts.



  1. VFS Sensor x1
  2. Stick Base Adapter x1
  3. #4-40 Phillips pan head screws x2
  4. #6-32 bolts x8
  5. Stick Base Spacer






  1. Phillips head screwdriver
  2. Needle nose pliers
  3. Small flathead screwdriver



    Step 1: Gutting the HOTAS Cougar

    1. Disconnect the Cougar from your computer.
    2. Disconnect the throttle from the stick base and set it aside.
    3. Unscrew the side stick controller from the base by turning the large mounting nut.
    4. Unscrew the four hex nuts next to the two connectors at the front of the Cougar stick base.  
    5. Turn over the Cougar Stick Base and remove the screws located in each  of the four corners. 
    6. Remove the bottom cover and set aside. 
    7. Inside the Cougar Stick Base, locate the PCB and remove the four screws securing it to the Cougar stick base. 
    8. Flip the PCB and disconnect the two potentiometer cables, and the cable that connects the PCB to the stick.
    9. Remove the eight screws that secure the two gimbals to the Cougar stick base.
    10. Remove the two gimbals.  They will fall apart as you do.  You may wish to save the parts in case you ever want to reinstall.  


    Step 2: Recovering the DIN Connector

    1. The five-pin DIN connector located in the original stick mount is a necessary component for reassembly.  Carefully remove the two Phillips head screws holding the DIN connector in place.
    2. Fold the PCB connector end of the wires of the DIN connector as shown below.  
    3. Push the PCB connector and wires through the original stick mount.  It should go fairly easily and without much force. 
    4. Gently pull the DIN connector as you feed the PCB connector through.  It may help to use a blunt object like the eraser end of a pencil to help push, and remove the entire DIN connector assembly.  Do not force it through.  Be gentle.  


    Step 3: Installing the DIN Connector

    1. Remove the two Phillips head screws from the VFS stick mount.
    2. Fold the PCB connector end of the DIN connector assembly as in the previous step.
    3. Feed the PCB connector through the top of the VFS stick mount and out of the bottom through the square hole of the VFS PCB. 



    Step 4: Installing the Cougar Base Adapter

    The VFS is designed to be either reinstalled in the Cougar stick base, or attached to our side stick controller base.  The following instructions are for reinstalling into the Cougar base adapter.

    If you prefer some play in the stick, you can use the provided o-rings as outlined below.  If you prefer a rigid mount, omit them.  Please note that the o-rings will make the force sensors more sensitive.   

    1. Take the #6-32 Phillips head screws and put them through the holes of the Cougar base adapter plate.  If you prefer some play, put small o-rings over the threaded ends of the screws.
    2. Place the Cougar adapter plate over the VFS and align the eight mounting holes.  
    3. Attach the Cougar adapter plate to the VFS with the #6-32 locking nuts.  If you're using the o-rings, do not over tighten the nuts or the stick won't move.
    4. BE CAREFUL while installing the nuts near the strain gauge.  As mentioned, the stain gauges, especially the wires, are delicate.  Avoid touching them.  



    Step 6: Sensor Assembly 

    1. Locate the steel ring atop the Cougar stick base that keeps the dustcover in place.  Replace the four Phillips head screws in it with four M3x30 Allen key bolts.   Drive them all the way in and secure them tightly.
    2. Replace the eight gimbal mounting screws from Step 1 to prevent dust entering the Cougar stick base.  Preventing dust intrusion is their only use.
    3. Feed the assembled VFS through the square hole at an angle as shown below.  
    4. Place the VFS with adjustment screws located to the back side of the Cougar stick base.
    5. Slide the VFS over the previously mounted M3x30 screws and use four M3 lock nuts and washers to secure the VFS in place.


    Step 7: Installing the PCB

    1. Reattach the stick PCB connector to the Thrustmaster PCB. 
    2. Connect the sensor cables to the PCB.
    3. Reattach the Thrustmaster PCB to the Cougar stick base in its original position using the original screws.  Do not forget to reattach the grounding wire.
    4. Reinstall the bottom cover using the original screws.


    The VFS is now installed in the Cougar Stick Base.



    Step 8: Manually Calibrating Your VFS

    1. Reconnect your HOTAS to your computer, and open the HOTAS CCP software.
    2. Go to the start-up & calibration tab.
    3. Click manual calibration.
    4. Go to the point where the software directs you to move y-axis forward, and adjust the y-axis trim pot using a small flathead screwdriver until you get a raw value of  324. You will not need to calibrate the Y axis back.  The value will be correct from the previous step.
    5. Click next until the software directs you to move the X-axis to the left most, then turn the x-axis trim pot until you get a raw value of 324.  You will not need to calibrate it to the right.
    6. Jump back to step 1 of the calibration menu.
    7. Now finish the calibration following the calibration steps of the HOTAS CCP menu.


    Curves and Dead Zones

    Depending on how and where you mount your Cougar stick base, you may need to adjust the sensitivity of the stick.  The sensitivity can be controlled by the curve settings in the HOTAS CCP axis shaping tab.  Adjusting the curve is a matter of personal taste.

    You can also set the dead zones, and they will not affect the curves.  We recommend a dead zone of 12 for the center of both the X and Y axis. 

    Mechanical Center Play

     You will experience some mechanical play in the stick while using the VFS.  Tightening the screw on the bottom of the stick may resolve some of the play, but it will eventually return.  You should install the included horse shoe-shaped spacer as shown below to eliminate mechanical play.  Press the ring between the stick and the adapter plate.  The gap between the two varies by Cougar unit, so you may need to sand the horse shoe ring to fit.  



    PCB-Lead Free HASL-RoHS

    Operating Voltage: 5v

    Thrustmaster HOTAS Cougar Adapter Plate Dimensions (mm):

    VFS Mounting Plate Dimensions (mm):