737 - 3D Printed Rudder Pedals
The Rudder Pedals was one of my most requested projects to date, delayed mainly by the time it took to create the MTU. I started the project on the 1st of Jan 2022, and many prototypes have been trialled. The main aim was to produce something that could be printed at home, fully operational, and withstand the immense forces exerted by the human foot. (This doesn't mean they won't break if they are abused! - After all, it's only plastic. Even making the parts much thicker, it's always going to have a breaking point.)
The pedals were made incredibly thick to withstand the loads starting. The pedal surround is around 2 to 3 mm thick; I increased this by 5 to 6mm. This had the effect of adding an insane amount of structural support. I knew straight away that the PLA would not be strong enough to support the weight of the foot and leg without additional support.
Several versions were trialled, and I released that the Print layer orientation was crucial. If the pedals were printed vertically, they would fit on a smaller print bed; but they would separate along the vertical axis when moderate pressure was applied to the pedal. I found printing them horizontal fixed this issue.
The rudder stems and bearings support the pedals. This, in turn, is then supported by an M12 threaded rod.
The pedal mounts over the square shaft, and the unit rotates about the thread bar to allow the brake axis to operate.
Again, if it is printed in the wrong direction, the adapter shaft in green can not withstand the load's placed on the brake pedal return spring, and the part separates along its vertical axis.
The next hurdle I came across was to get the pedals to return with force. I wanted to use gas struts, but they still have not arrived four months on. In the photo to the right, the spring return levers allow the springs to tension when the pedals are pushed but move backwards when the pedals are moved forward. The bolts allow the centre position to have pretension loading applied and ensure the pedals are aligned in the neutral position. I ended up adding four springs because I wanted a lot more force in the pedals. 2 springs were too weak for my liking. All my springs come from an Amazon assorted spring box.
The yellow base is mounted on six 608 roller bearings. The whole unit then moves back and forth along a 12mm threaded rod inside the 3d printed centre housing.
Sprockets and chain, then turn this rod from the handle at the front.
This project is a massive print that took me over two weeks. I used a 0.4mm nozzle for all the significant parts. Looking back now, I would change to a 0.8mm nozzle, which would considerably rescue print times. Creating the footplates and centre structure from wood is quite an easy task for those with more capable hand skills. But for this unit, I wanted to prove that it can be done with a button click. Be warned! This design will eat through 4 rolls of PLA. I may have overdone the infill, which has produced parts that are rock solid!
We have been testing the pedals for about 11 days now, and we have not had a single issue. I currently have them connected to an Arduino micro pro, as they currently only use three axes. If you decide to go ahead and build this unit, please let me know of any feedback or comments in the forum.
If you are interested in the STL files, they can be found here:
https://www.737diysim.com/product-page/737-3d-printed-rudder-pedals-stl-only
If you would like the CAD files, they can be found here:
https://www.737diysim.com/product-page/3d-printed-rudder-pedals-stl-cad
The Build/Parts/ and print guide can be found here:
https://www.737diysim.com/build-guides-1
Kind regards, Karl