Wings of Honor
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Hardware Reviews

Thrustmaster HOTAS Cougar Modding - U2Nxt Gimbals and Hall Sensors Review

by Gremlin, Wings Of Honor Staff
on 18-Jul-2009


When I bought my Thrustmaster HOTAS Cougar I wanted to replace my 15 year old Thrustmaster PFCS Stick and MKII Throttle combination with something better in terms of usability and programmability. The first contact with the Thrustmaster HOTAS Cougar was when it was on display in a electronics shop. I was impressed with the all-metal construction and the various switches and hats I found on it. Being mainly a W.W.I sim pilot I know this is not an authentic setup but then you have no choice at all to buy something like a Camel- or Fokker-like stick and throttle combo. Thus the decision was made to take the plunge.

I had to spend 210 Euro for the HOTAS Cougar and that seemed somewhat expensive to me. But then I had used my Thrustmaster PFCS and Throttle MKII combo for what was then 15 years (yes, 1993 to 2008). I expected the Cougar to last at least the same timespan and I was fine with the decision. The HOTAS Cougar is a sturdy piece of metal and has the best design for my hands I ever experienced. The only thing I found out during the first week I owned it was a little annoying play around the center position of the stick. I found out that this was not a bug but a feature. I had already browsed the forums at Cougar World, the hub of the Cougar User's Community, and knew about the strengths and weaknesses of the Cougar. But reading about issues (some forum posters tend to exaggerate) and experiencing them myself is a different world.

At that time I had read about the benefits of various mods for the HOTAS Cougar and when buying it I already had in mind to upgrade it with modded parts one day. As my Cougar stick developed an unhealthy tolerance during the first year this day came in the end of April 2009 when I ordered a mechanical mod - the Uber2Nxt (short: U2Nxt) made by Ian Johnston - to replace the stock gimbals of the stick and two electronic mods - the +HS2 Hall Sensor Kit for the stick and the +HS1 Hall Sensor Kit for the throttle provided by Ernest 'Cubby' Smith - to replace the stock analogue potentiometers for the HOTAS axis. My stick had lots of play in the center: measured on the top of the handle it was 5mm of travel left and right and 3 mm back and forth. I found this too much.

The order process for the parts I made via e-mail order and PayPal money transfer. Ian Johnston is making the replacement gimbals on a CNC machine and does productions runs from time to time. So I decided to buy it accidentally when just some of them were left from his latest production run. The best matching for those gimbals are the hall sensors by Ernest 'Cubby' Smith which I ordered accordingly together with a replacement kit for the throttle axis. As these parts are produced and distributed in fairly low numbers as a private initiative the prices for the parts are related to these circumstances. It is quite an investment but being a flight sim nerd and knowing it would even extend the life-time of my HOTAS Cougar I could justify spending that money.

The Mods

HOTAS Cougar - Modding parts - Picture by Gremlin (08-May-2009)

The Uber2Nxt gimbals came from Australia and the Hall Sensor Kits from USA. The first needed 15 days for shipment around half of the world, the later ones 6 days over the Big Pond to Germany. All parts were carefully packaged and arived safely. I ordered the U2Nxt gimbals and a set of four replacement springs from Ian Johnston, a +HS2 Joystick Sensor Kit, a +HS1 Throttle Sensor Kit and an Antifriction Throttle Kit from Ernest 'Cubby' Smith. In the following the contents of the packages are listed.

The benefits of the U2Nxt gimbals over the stock gimbals are the following:

  • Extensively precise construction for smooth control
  • Nearly no wear because of small ball bearings for each axis
  • Prepared for mounting the very precise hall sensors

Contents of the U2Nxt Mod Kit

  • Gimbals with the four springs already mounted
  • 1 replacement spring
  • Screws, nuts, spring washers, flat washers
  • 1 special tool for adjusting the hall sensors
  • 1 CD ROM with installation guides

Contents of the replacement springs kit

  • 4 replacement springs

Ernest 'Cubby' Smith offers various Hall Sensor Kits. The ones I ordered were the +HS2 Hall Sensor Kit for the U2Nxt Mod and the +HS1 Throttle Kit.

The benefits of the Hall Sensor Kits over the stock analogue potentiometers are the following:

  • Precise readout due to electromagnetical signal generation
  • Nearly no mechanical wear because of contact free read-out
  • No spiking, signals stay constant without jitter, helps the precise readout of stick/throttle position values

Contents of the +HS2 U2Nxt Joystick Kit

  • 2 hall sensors
  • Splice connectors
  • Cougar Joystick Shaft Fix Kit with a set of special Allen screws
  • Short installation overview (extended version on website)

Contents of the +HS1 Throttle Kit

  • Hall sensor mounted on a bracket with hall sensor arm
  • Splice connectors
  • Screws, nuts, various small parts
  • Short installation overview (extended version on website)

Contents of the Anti-Static Friction Kit

  • Special anti-friction tape
  • 1 syringe with grease
  • Installation guide


HOTAS Cougar - Necessary tools - Picture by Gremlin (11-May-2009)

The installation process for the gimbals and the hall sensors is covered extensively in several step-by-step installation guides with lots of photographs. Each step is described in a detailed manner and there are no questions left open. The installation covers the removal of the old potentiometers and gimbals of the stick, the installation of the U2nxt gimbals and the hall sensors, the removal of the old potentiometer of the throttle and the mounting of the new hall sensor construction as well as the calibration of the new sensor with the help of the Cougar Control Center software. Also there is a hint in the short description coming with the joystick's +HS2 hall sensor package pointing to James 'Nutty' Hallow's guide called 'Using calibration data to centre the NXT physically and electrically'. This guide is imminent for a correctly conducted hard- and software calibration of the newly installed joystick gimbals and hall sensors.

The ability to conduct the removal of the stock parts and the installation of the modded parts depends mainly on the fact if one can operate the tools shown in the picture on the left-hand side. The right-most toll is provided by Ian Johnston and helps adjusting and fastening the hall sensors. Also some experience with handling screws and nuts would be beneficial. Also keep in mind a very crucial slogan when it comes to tightening screws: "After fixed comes overwound!"

By the way, I used the gas pipe pliers on the left in the picture only for squeezing the splice connectors. Not that they needed the force but I could squeeze the splice connectors better with the surfaces of the pliers staying always nearly parallel to each other.

The Joystick

HOTAS Cougar - Stick in original configuration - Picture by Gremlin (08-May-2009)

Installation of the new gimbals took about two hours. Other than described in the installation guide the springs were already installed on the gimbals and the brass lugs already greased. A nice surprise. First the Cougar stick had to be dismantled and the old pots had to be cut from their wires and removed. After that the stock gimbals had to be dismounted. As they are covered with red grease all over this one needs to wash hands a lot. A tricky task was to feed the bunch of wires that connect the stick base with the stick handle through the shaft mechanics. As the wires end in a small connector this one had to be carefully fed through the shaft hole. After this had been accomplished the dismounting part of the work was finished. Most likely the small white connector ends up covered with grease. No problem, just take a little bit of isopropanol (isopropyl alcohol, don't drink it) which you can buy from your local drugstore to clean parts from fat and grease. Isopropanol is my preferred cleaning medium for electronic devices and such.

HOTAS Cougar - Stick with stock gimbals - Picture by Gremlin (08-May-2009) HOTAS Cougar - Comparison stock gimbals (foreground) and U2Nxt gimbals (background) - Picture by Gremlin (08-May-2009) HOTAS Cougar - Joystick handle with blue marker on the areas to be sanded - Picture by Gremlin (09-May-2009)

Assembly started with another tricky part: filing of the Cougar handle's flange to adjust to the U2Nxt's interface. Due to an issue with Thrustmaster's manufacturing tolerances this step is necessary. Only small amounts of material had to be filed and the correct fitting of both parts had to be tried several times. One thing helped me: I took a blue marker and painted the areas I had to file to see what to file and how much. After each marking I tried to connect handle flange and U2Nxt interface and then saw where I had to file some more. An old trick I was teached in my younger years. As I was very careful not to file away too much this step took a considerable amount of time. But the result was very good. No play between both parts.

HOTAS Cougar - U2nxt gimbals with hall sensor kit +HS2 mounted - Picture by Gremlin (09-May-2009)

Assembly of gimbals and hall sensors and installation of all parts into the Cougar stick's base was easy as the installation guide has a picture and a description of each step. Also the hall sensors had to be connected to the stock wires. The necessary steps are explained in an extensive installation guide which can be downloaded from Ernest 'Cubby' Smith's website. It contains also pictures and text to accomplish this task. There are two possibilities for connecting the new hall sensors to the stock wires: the first involves soldering and the second one the splice connectors delivered with the +HS2 Kit. As I was too lazy tosearch for my soldering equipment and as a good splice connector does the job too I opted for the connectors. The pipe pliers made the squeezing of the splice connectors easy with good control of the applied forces (very minimal). The tricky part is to stick both wires into the splice connector with one hand holding them there and using the pliers with the other hand. Sometimes a third hand would come handy. It is imminent to double check the connection of the wires else the hall sensors get distroyed. Not so easy when done at 1 a.m. in night time when being tired and experiencing crossing eye view. But with the splice connectors Ernie Smith makes it easy for everyone to connect those hall sensors elecrrically. After that and after assembly of the stick the main mechanical work on the stick was done.

HOTAS Cougar - Joystick base with U2nxt gimbals +HS2 hall sensors mounted - Picture by Gremlin (09-May-2009)

As already mentioned above the stick's new gimbals and the hall sensors needed to be calibrated manually. The tutorial by James 'Nutty' Hallows describes this procedure extensively. It involves the use of the Cougar Control Panel and a little bit of calculating calibration values. The stick base had to be opened once more to adjust the hall sensors and gimbals manually as the weight of the handle pulls the stick slightly forward due to the circumstance that the U2Nxt mechanics are smoother (less friction) and the springs are softer than the stock ones. I had to adjust the hall sensors and gimbals only marginally. The small wrench provided by Ian Johnston with the U2Nxt Mod comes handy as it reaches easily in the gap between hall sensors and gimbals. Also it is made from aluminum and will bend before you can damage the hall sensors by applying too much force. Well thought out. It simply can be bent back after that has happened. The whole procedure took me about one hour as I am a methodical worker when precision is needed.

The Throttle

HOTAS Cougar - Throttle in original condition - Picture by Gremlin (09-May-2009)

Work on the throttle started with dismantling it and removing the grease from the throttle base with isopropyl alcohol after removing the shaft from the base. This was to install the anti-static friction fix I had ordered it additionally to help overcome the friction when starting to move the throttle. The anti-static friction fix is basically a special tape to be wound around the throttle shaft. The tape is located between the drag adjustment arm of the throttle and the throttle shaft and helps smoothing the friction between both. Again the instructions were precise and clear. The tricky part was to remove the grease below the throttle shaft bearing. But with a small cotton swab moistened with isopropyl alcohol it can be done easier. After that the tape had to be applied. With the help of the syringe the tape was attached to I managed to wrap it around the throttle shaft without generating bubbles in the tape. After having finished this part I greased the bearings with the grease contained in the syringe and assembled the throttle shaft parts.

HOTAS Cougar - Throttle axis in stock condition - Picture by Gremlin (10-May-2009)

The next step was to install the Hall sensor throttle kit. By removing the printed circuit board from the throttle base earlier I could detach the stock potentiometer from the throttle shaft. The original wiring of the potentiometer had to be cut and I connected the wires of the new hall sensor with the provided splice connector to the remaining stock potentiometer wires just as I did with the stick's hall sensors. Other than the hall sensors for the stick the hall sensor of the throttle is mounted on an aluminum base - the sensor bracket - which needs to be attached to the throttle base on one of the screw holes of the printed circuit board, which I did. So far so good. After that I needed to determine if the throttle hall sensor was adjusted correctly on the sensor bracket. This involves the use of the Cougar Control Panel software and the small aluminium wrench provided by Ian Johnston. These steps took me another two hours including calibration work and getting some cups of coffee.

HOTAS Cougar - Throttle axis with anti-friction kit (clear special tape) and +HS1 hall sensor kit mounted - Picture by Gremlin (10-May-2009)

Now the moment of truth came when I fired up the W.W.I flight sim 'Over Flanders Fields' and entered my trusty Fokker Dr.I to see what the improvements were. And man, those were improvements! I never experienced such a precise and smooth stick control and the throttle commands to the engine could be done with very subtle movements. The plane was totally different in that it responded to the stick input more instantly than before without stick play. The stick movement before the modding could be described as 'squarish' with the stick trying to align along its x-and y-axis while the user tries to move it diagonally. Additionally the experienced stick play did not really help the cause. Now both were completely gone and - may I add now that I am finishing this review after more than two months of use - not one iota of it came back. Still the same stick and throttle experience as directly after installation of the modding kits. I am positive this will stay this way looking at the high quality parts I have bought. Before the stick would have some control over the user's movements and now the user has the total control over the stick.


HOTAS Cougar - Working place of a sim pilot - Picture by Gremlin (10-May-2009)

The result of all the work described above is a perfectly working HOTAS Cougar. A precise instrument for the hobbyist sim pilot.

The U2Nxt gimbals, the +HS2 and +HS1 Hall Sensor Kits for joystick and throttle as well as the Throttle Anti-friction Kit are extremely precise devices and are well worth the investment given the fact that they provide unsurpassed precision and longevity for the HOTAS Cougar. You are experiencing the precision especially when flying the very twitchy Fokker Dr.I. With the U2Nxt and +HS2 hall sensors mods the simualted planes become very stable gun-platforms. The W.W.I crates - normally a little bit nervous - can be controlled much better and with the more steady aim the hit rates go up in dogfights.

If you plan to mod your Cougar as described above pick a prolongued weekend as I am damn sure you want to fly your 'new' HOTAS quite a bit after modding it ;o)


With the U2Nxt and Hall Sensor Mods the control of simulated planes reaches a new level of precision and fun. It involves quite a financial investment and also about 5 - 6 hours of of dismounting and assembling work but it is well worth the effort.

The U2Nxt and +HS2/+HS1 hall sensor mods are definitely a must for the flight sim and HOTAS Cougar enthusiast. They have my recommendation. If you spare the money for your next investment in computer hardware then keep your current PC system a little bit longer and instead invest into those mods for the benefit of your Cougar and your flight simming experience.


Cougar World
Cougar Hardware Forum on Frugal's World Of Simulations

NOTE: The above links are dead as Cougar World is currently down since several weeks (as of 13-Oct-2009). I have set up a temporary forum temporary forum as long as Cougar World is offline.