William's Workbench

I have started work on a magneto/starter switch for my cockpit simulator. This will be a 5-position switch with Off-L-R-Both-Start positions. The start position will spring return to the both position.

.

This is a 4-pole, 3-position switch that I modified to be a 1-pole, 5-position switch. I chose it because it would have a 30° spacing between positions and it was readily available at my local electronics shop. The modifications included a bit of tweaking to the physical limit ring to allow 5 positions and removing 3 of the 4 wipers to get just one pole. The picture on the right shows the end of the shaft modified to a “D” shape. You’ll see why in a bit.

.

Here is a C&K 3-position key switch. I have removed the switch part and modified the key insert for full 360° rotation. It is a little hard to see, but the key insert has a “D” shaped hole that mated to the removed switch. This of course will match nicely with my rotary switch shaft.

.

With the help of some shim stock (the little squares next to the motherboard standoff for reference) the rotary switch hooks up to my key switch. The next step is to build a bracket and some sort of spring action to return from the start position.

I asked for and received the book Building Simulated Aircraft Instrumentation by Mike Powell for Christmas. I’ve nearly worn it out already. It is a good read with some very sound ideas on construction of simulated instruments. Mike has done a great job of breaking down the process so anyone with patience and a few good tools can make instruments.

I think I will start with a stepper-powered airspeed indicator. The air-core movements look interesting but I have a box full of stepper motors and am familiar with driving them.

I high recommend this book to anyone wanting to build their own instruments.

It’s not covered in this book but I also have a prototype of a nav/com unit started. This unit will connect via USB and provide a general aviation style nav/com unit modeled after the Bendix 155a.

UPDATE: This book is out of print. I am not able to scan this book. I do not want to sell this book. Please see the author’s site for more information. Thank you

I started work on a panel for my flight simulator. The material is Masonite paneling, about 1/8″ thick. The drawings came from here and I added center points for all the big holes using a free trial of AXCAD.

I printed the drawings full sized to a 24″ by 72″ sized PDF using CutePDF and then converted that PDF to a PNG image using ImageMagick. Finally that image file was printed on letter size paper on my Laserjet 4M using PosteRazor. After a lot of taping and measuring I had a paper template for my panel. I traced the outline using a pencil and transferred hole centers using an automatic center punch.

I cheated on the gauge sizes because the “standard” sizes are metric and hard to come by here in Imperial land. I used 2 1/4″ (57mm) and 3″ (76mm) instead of 56mm and 79mm. The gauges will most likely be made by me anyway so the slight size difference shouldn’t be noticeable. The next step is to build something to mount this to.