Hotas Cougar Gimbal Redesign by hberg32

Last crawled date: 3 years, 3 months ago

This is a replacement for the notorious gimbal mechanism used in the Thrustmaster Hotas Cougar. This design is influenced by the work of olukelo and debolestis. There are a few key goals with this design:
Retain the factory post (the piece that the grip's M25 ring screws onto)
Allow for either a spring-centered or cam-centered assembly
Required Hardware
(2) Littlefuse 55300 hall sensors
(2) 5x5x3mm neodymium magnets
(2) MR106 bearings
(2) 688ZZ bearings
(3) 40mm M3 bolts
(2) 30mm M3 bolts
(6) 25mm M3 bolts
(4) 20mm M3 bolts
(2) 15mm M5 bolts
(4) 10mm M2 bolts
(4) 25mm M4 flat head bolts
4-8 1 inch or 25mm extension springs
(4) M4 washers
Springs
I found that the Cougar's grip is so heavy that I needed fairly stiff springs just to keep it from flopping over. The spring force is very important to pay attention to. I ended up going with Grainger 1NBH6 springs which have a spring force of 18.94 lbs/inch. 4 of these are enough to hold the stick upright and will give a fairly loose feel. Doubling these to 8 springs gives a pretty stiff feel. Using 4 1NBH6 and 4 1NBH4 (which has a spring force of 10.6 lbs/inch) gives a balanced feel.
Cams
The dual cam mechanism created by olukelo is a fantastic alternative to springs and I have included mounting holes in this design so that they can be used HOWEVER, they are too tall for the Cougar's base. I'm exploring the idea of a printable base height extension but would welcome any ideas on how to design shorter versions of these cams.
Printing
Use plenty of infill for strength. Rotate parts so that surfaces vital for concentricity (such as bearing holders and pivot block posts) face upward. The only part that is tricky to print is the stick surround. Split this part in half when printing and use high detail. The stick surround needs to grip the metal factory post tightly and fit precisely between the bearing planes to avoid any stick wobbling or center play. This part is designed with 0 gaps for mechanical tolerance so sanding will almost certainly be required where the ball bearing grips the stick surround.
Assembly
Be careful not to overtighten screws to avoid stripping the holes. I have not modeled any nut traps in the parts because I think they will weaken them so all bolts here just screw into the plastic. I believe the parts are thick enough that the bolts will not loosen but time will tell.

Completely disassemble the old gimbal mechanism and hurl both it and the potentiometers it came with into the nearest convenient dumpster, lake, or bonfire. Carefully tease off the JST connector from the wires coming out of the metal post and remove the mini-din connector. This will ensure you don't nick the wires when running a reinforcement bolt later.


Screw M5 bolts through the pivot blocks to provide reinforcement


Screw M3 bolts through the the smaller post on the pivot blocks. This is to provide reinforcement so the spring forces don't break off the post. Run the screw from the inside (same direction as the M5 bolt), that way when installing the springs you don't have to get them over the bolt head.


Screw M3 bolts into the cam follower/spring mount posts in the stick surround. These are also for reinforcement and should be screwed from the inside out. There are two posts on each stick surround piece, the cam follower/spring mount is the one that does not have a flat circle around it.


Sand the mating surfaces of the stick surround pieces to ensure they grip the stick tightly or else the stick will have a little wobble. It is not necessary to sand the inside curve surfaces. The flat surface around the pivot posts will be gripped by the bearings. It is important to file these a little bit to ensure that the assembled stick surround measures exactly 28.5mm wide at these flat spots. Over sanding will lead to a bit of stick wobble which can be corrected by adding an M3 shim. Under sanding will lead to a poor fit of the bearing planes. If you don't have calipers use the pivot blocks as a measuring guide. The assembled stick surround should be the same width at the flat spots as the pivot blocks.


Press 688zz bearings into the brackets. Tap these down to make sure they go all the way in. Press MR106 bearings into the bearing planes.


Put the factory metal post into the joystick housing first, then place the stick surround pieces onto it and secure them with 4 M2 bolts. If you assemble the whole gimbal outside of the housing and try to put it in afterward you'll find that the metal post doesn't fit through the hole in the housing. Not that I made that mistake a few dozen times. :)


Place the bearing planes on the stick surround with the bearings facing inward. The pivot posts should go through the bearings. Run a single M3 bolt through the pivot posts to secure the planes and to provide reinforcement.


Mount the pivot blocks using M3 bolts. Use longer bolts in the upper holes and leave them sticking out a bit - the springs will go over these bolts.


Put a magnet in the notch in one of the pivot posts and attach one of the Littelfuse hall sensors over it. Both bearing planes have holes for the sensor but it should be mounted on the one facing the rear of the controller. If you put it on the front plane then left/right stick movement will be backwards.


Attach the other Littelfuse sensor to the left-hand bracket. If you find that forward/backward stick movement is reversed then move the sensor to the other bracket.


Place a magnet in the notch in the pivot block post.


Place the brackets on the pivot blocks.


Bolt the gimbal assembly into the joystick housing.


Run M3 bolts into the brackets (direction doesn't matter).


Install the springs.


The circuit board is secured by 4 screws but we actually need to shim it out a little - otherwise the bolts for the springs will come into contact with the board at full stick deflection. Before putting in the circuit board, run in the 2 screws nearest the center of the joystick assembly, then put in the circuit board and secure it gently with the other two screws. The screw heads provide the perfect amount of shimming (about 5-7mm).


Shimming the circuit board will bring it into contact with the metal baseplate and cause a short circuit so the baseplate needs to be shimmed a little as well. Tape M4 washers over the holes on the inside of the baseplate before putting it back on.

Calibrate the joystick before using it via the Cougar Control Panel app. The Littelfuse sensors return a smaller range of analog values than the original pots did so without calibration you won't be able to get into all four corner.
Good luck and don't let the magic smoke out.
Influences
https://www.thingiverse.com/thing:2496028https://www.shapeways.com/shops/debolestis