P-51B Canopy Release (Authentikit Compatible)

This is a recreation of the P-51B Mustang canopy release lever, combined with a mount and dual-action electronic switches, for use in flight simulators. It was designed to mimic, as closely as possible, the size and shape of the original, real thing. The mount is designed for mounting on 1515/1530/3030 extrusion. There are two attachment points, so it could also be mounted to most any flat surface. The electronics are pretty straight forward and designed to integrate into the Authentikit flight control system (authentikit.org). I specifically made this with two switches so that pulling the handle part way can be mapped to canopy release and pulling it the entire way can be mapped to bail out, before I realized that IL-2 only supports a single mapping for both. If you plan to fly a sim with just a single mapping, then you only need a single switch.

In addition to the printed files you will need several other components to complete this build:

• (1) female RJ-45 jack (Authentikit compatible)
• (1) 5/16" x 3" bolt (this will require modification. A grinding wheel or metal file and drill with bits are necessary)
• (1) M5 50mm bolt
• (1) 3mm x 18mm screw
• (2) 1.9mm x 24mm screws
• (1) compression spring. Slightly larger than the 5/16" bolt, about 30mm in length
• (1-2) electronic 3-pin 10T65 micro switches with roller tip
• (1) 608 sealed bearing
• (1) M4x8mm bolt
• (1) Washer with 5/16" inside diameter (fits over 5/16" bolt) and no larger than 17mm outside diameter 
• A few inches of ~14 gauge wire for switches. I suggest 2-3 colors.

This model went through many iterations until I finally made something I was happy with. However; it is not an easy build and will require hand tools. You should be able to find all of the bolts, springs, bearing, etc. at the local hardware store. The microswitches can be ordered from Amazon or any other electronics retailer.

The handle itself should be printed face down. The text is recessed and can be filled with silicone caulk or wax, but can be printed multi-color or with two layer swaps. PLA is plenty tough in my testing, but I recommend using 5 walls for strength. Support is needed, as there are unsupported overhangs. Use manual support for the bearing recess and surrounding area. That's all that is needed.

The cam mechanism and housing for the electronics are also printed in PLA. Again, support is needed in very specific areas. I suggest using manual support in your slicer and use dedicated support material if you have an AMS. Support is only needed in the shaded areas:

The main body and door are designed to be printed in place. Don't separate these two parts or you may not be able to get the door back into place. Use manual support, and only in the shaded area:

They switch ports have a one layer thick infill at the base, so as long as your printer can span that opening cleanly, you do not need support in the switch areas. You will need to drill through this single layer before inserting screws to hold the switches. If you use automatic support, you will get support material in the switch openings and are unlikely to be able to remove it cleanly. 

NOTE: I have added a test “bolt” to replace the purchased steel one. I have tested this part for fit and function, but not for longevity. It's not clear if a printed part of this size is strong enough to withstand repeated use. I recommend printing with 5 walls for strength at the small end. PETG may work better than PLA, but I have not had time to test it.

Before trying to assemble everything, read through the instructions below. Get an idea of where each of the screws goes and how they are threaded, then make sure your parts assemble smoothly. You may need to drill out the holes to retain the switches, pre-thread the bottom of the unit where the M5 bolt threads in, or clearance other areas where screws go through or thread into the print. Check all of this thoroughly first, because you don't want to have to remove anything to fix it later. Getting the switches back out once they are in is difficult, and you only want to put the cam and handle into place once.

To assemble:

1. Solder or crimp wires to both switches. I recommend black for ground, yellow and blue for hot.
2. Drill (or punch out using the screws) the bottom layer of material in the switch openings.
3. Insert switches into base as shown, wires first.
4. Insert 1.9mm x 24mm screws through the top to retain switches.
5. Wire switches to the RJ-45 connector and insert it into the rectangle hole, using a common ground. It's up to you how you wire these, but note which pins are used for each wire so that you can wire them up to the UniHub later.
6. Close the cover.
7. Insert the M4 stop screw into the top where the handle protrusion meets the body. This can be adjusted in or out to adjust the stop position of the handle when not in use.
8. The 5/16" bolt must be ground down to fit between the gap in the cam mechanism, then must have a hole drilled into it to allow a 3mm hole to pass through. The end also needs to be rounded for clearance, because the cam pivots as you pull. Note: This part can probably be replaced with a 3D printed alternative, but it experiences a lot of stress and wear, so I haven't tried it yet. Maybe in a future revision.
9. Put the washer on the 5/16" bolt, then put on the spring.
10. Put the bolt with washer and spring through the two oblong holes from the rear.
11. Put the 3mm screw through the top of the small hole in the cam mechanism, then through the hole that was drilled in the 5/16" bolt, then into the bottom of the cam mechanism. This will hold the cam to the end of the bolt.
12. Insert the 608 bearing into the recess of the handle.
13. Attach the handle to the cam mechanism. This is a tight fit. Sand lightly, if needed.
14. Move handle and cam into place. This step can be a bit of pain because of tight tolerances and little room to maneuver.
15. Secure the handle in place with the M5 bolt. It will pass through the top and thread into place in the bottom.

That's it. You should be able to hear each of the switches click as you move the handle through its range of motion. If they trigger too soon or too late, you can very slightly bend the metal lever on the microswitches to adjust them. There are two beveled holes on the bottom for attaching to extrusion or another surface. This can be connected to the UniHub like any other Authentikit item, or you can wire it to an Arduino or other controller if you know what you're doing.

Please do not contact me with help in wiring. This is a pretty straight-forward build with only a few wires. It should be pretty easy to do for anyone who is familiar with these sorts of builds. If you don't know how to wire it, please research on your own before trying to build this unit.

The handle model was borrowed from Stiggles on the Authentikit forum, with some edits to make it work correctly in this application. Special thanks to him for giving me the 3D files needed to get this project off the ground. The rest of the mechanism was made from scratch, but closely matches the original dimensions and operation.