I'm quickly approaching the point where all the major airframe systems are done, and the major systems left to build are getting smaller.  I've got to make one more wing skin, and then I won't have any more major layups except for the engine cowling, so yesterday I ordered a Megasquirt engine controller.  I'll work on getting it built while I finish the electrical, panel and canopy installations.

I'm investigating using two Ford EDIS ignition controllers.  They will work without computer input, set for 10 degrees of advance.  It just needs a power source and input from a vr sensor.   In normal operation, the computer sends a correction signal that the controller uses to change the spark advance.  One EDIS would be set to control the leading plugs with a wasted spark, and the second would control the trailing.  It promises to be a very robust setup with multiple redundancies.

I still need a toothed wheel for the vr sensor.  The EDIS system requires a 36-1 wheel (36 teeth with 1 missing).  I'm thinking that one of the old bicycles that my boys never use may end up missing a chain sprocket.  (As a nod to the original homebuilders, I think every homebuilt airplane should include at least one bicycle part.)