Thrustmaster Rudder Control System (RCS) mods, Part 1 - Adding hardware for the toe brakes.

I recently picked up a Thrustmaster RCS off of ebay for a fair price. I wanted a set of rudder pedals, but there aren't many options so I decided the RCS would fit my need, if I added toe brakes and converted them to USB.

Parts/Tools needed:

• Drill w/ various drill bits
• Dremel or some tool to do grinding
• Hot glue gun
• Pliers, wrench/socket set and screwdriver (used to tighten bolts and nuts)
• 2 Torsion Springs with the inner coil diameter being larger than 1/8"
• 2 1/8" x 5" bolts with lock nuts
• 2 #8-32 x 3/4" bolts + 4 nuts (1 1/2" length would work as well)
• 2 #8-32 x 1 1/2" bolts + 2 nuts + 2 washers
• 2 Knex Red Gears
• 2 Knex Gray Gears
• (Or a 3d printer to print your own)
• Arduino Uno  Pro Micro board (for part 2)
• Some wiring to rewire pedals (solid cat 5 cable would probably work, part 2)

The beginning of the project.

First, I removed the plastic pedals and pedal brackets from the unit. This was fairly easy, just remove the bolt from each side of the pedal and then the 2 bolts connects the metal pedal bracket to the bars. Repeat for the other pedal.

Pedals removed, going after the pedal brackets.

After I had the brackets removed, I started doing some research on how I wanted to go about adding the brakes. I come across a few different methods which gave me enough information to tackle it in a way which I thought would work best. I decided I would follow 9Thumbs method of reversing the pedal plates and attaching the pedals at the higher end of the bracket. I thought aRareKindofMonster's suggestion of using a torsion spring was simple and clever and decided that would be the way to go. I also used Ray's method as a general guide.

I went to the Part store and picked up two 1/8" x 5" bolts with locking nuts, some #8-32 x 3/4" and #8-32 x 1 1/2" bolts, nuts and washers, and some some torsion springs. I wasn't actually able to find any torsion springs, so I ended up getting a bag of spring clamps and removing a couple of springs from there. Out of that bag, only the 4 largest clamps (9 inch and 6 inch, I think?) have a spring that is large enough to fit over the shaft of the bolt.

Some Parts

After some mock fittings, I realized that I would need the round the upper corner of the pedal brackets to be able to freely rotate the pedal once it was mounted. I took a washer and placed in the top corner to use as a template to get a nice round curve and then used my dremel knockoff to ground the corners down.

The front bracket has rounded corners, the other does not.

 Once the corners were rounded off, I went ahead and drilled the new holes for the pedal shaft. I had some issues with the drill bit wondering off my mark when trying to start the hole so I clamped a washer on to use as a guide. It worked pretty well.

The hole is drilled.

I went ahead and put the pedal on the bracket to give it a test. At this point I realized I had overlooked something. I did not consider needing a way to stop the pedal from going back to far. This would cause two issues: the torsion spring pushing the pedal back so far there is not tension on the pedal and the bottom side of the pedal could get caught on the glide bar. I then realized the real benefit of the gas spring was it would limit the max travel of the pedal in both directions while the torsion spring would only limit one. To rectify this, I drilled a small hole and ran one of the smaller bolts through to limit the back travel. If I made the torsion spring tight enough, it would prevent the spring from getting loose as well.

Another hole

From here, I put in the stopping bolt and the pedal with the spring to figure out where I needed to place another bolt from the other side of the spring arm to push against. I made sure there would be a little bit of tension when the pedal was in the resting position. I then put in a 1 1/2" bolt in the hole and adjusted the spring arm to push against it.

Sorry for the blurry photo, the reflective glare was messing with my phone's auto focus.

Now I had to figure out how I wanted to mount the potentiometers to measure the toe brake movement. I got a 5 pack of 100k linear Amco pots of  Amazon for this part. I decided to follows Ray's Idea and use a couple of gears, but instead of ordering KNEX gears, I made my own on my 3D printer. I quickly created a 34-tooth and 14-tooth (same as the KNEX gears) using thingiverse customizer <TODO add link to STLS> and printed them out. I then used hot glue to attach the larger gear to the pedal and then lined up the smaller gear to eyeball where the holes were needed for the pots.

I made the hole diameter of the gear large enough to snugly fit around the bolt lip that protrudes from the plastic pedal.

The pots need two holes; one for the shaft and another for a little foot that prevent the pot base from spinning. Once the holes were drilled, I installed the pots and the smaller gear. I also added some extra hot glue to help hold the gears in place.

Pretty snug fit.

At this point, the hardware modifications were finished and I was happy with my work overall. Now I need to mount the brackets back to the rest of the unit and start on the wiring. This will be covered in Part 2.


Other notes:

One thing I had an issue with was the holes for the stopping the pedals from going too far back were off so one pedal would rest at a slightly different angle than the other. To fix this, I just left the stopping bolt a little loose which allowed the pedal to move a little more making them even.

Part 2