Start switch update

panel-063 panel-062 panel-067

I constructed a bracket from 1/16″ aluminum stock to hold the rotary switch and key assembly. It would make a machinist cry, but not too bad for basic hand tools and a bench vise.



This was a fun installation…



Clear prop!

4 Responses to “Start switch update”

  1. Dave says:

    Hi William,

    Just curious, did you manage to come up with a spring”system” to return the key to the both position after the engines is started?

    Many thanks, Dave

  2. Hi Dave,
    I intend to but that got put on hold when I started building an instrument. 🙂 The rotary switch I used doesn’t have as positive of a “click” as I would like so I may end up completely redoing the switch. You can check out the brochure for the SimKits start switch at, I plan to use a similar spring mechanism.


  3. Dave says:

    Thanks for the quick reply. I have seen and printed the simkits brochure. Without having started to tinker a couple of things I am not quite clear on.

    1. does the “long bolt” pass through the spindle coupling? (see Top View drawing on page 1 of brochure). Not sure how it could and still engage the shaft of the rotary switch.
    2. does the head of the “long bolt” just rest against the spring when the key is at the start position? I would think it has to put a bit of tension in the spring in order for it to return.

    Might be one of those things you just have to get the pieces and then start playing around with it. Making the clamp may be the toughest part.

    Cheers, Dave

  4. 1) I haven’t built this but I assumed the long bolt was threaded into the coupler and acted as another set screw to hold the coupler to the switch shaft.

    2) I believe the bolt should rest against the spring when the key is in the BOTH position. When the key is rotated to START then the bolt pushes against the spring and wants to snap back to BOTH.

    Feel free to email me (look for address on About me page) with questions and comments.