The next step for the alternate air was to try out the linear actuator that has just arrived.

I’ve used hot glue to try different positions. The switch is to give a cockpit indication that the door is OPEN. Otherwise I might accidentally activate the switch and never know it and so letting unfiltered air into the engine. The other thing is if the switch is mechanically triggered I know that its working and the door is open. I’m told those actuators can fail in time so it means this will be on my occasional checklist and certainly at 50 hourly intervals with the oil changes.

Here we are working with the hot glued parts in place.

I’ve epoxied the fittings in place. Unfortunately it was not perfectly aligned but still seemed to work. If I have problems later I know how to fix it.

After a clean up the parts are certainly well secured. I’m always thinking of engine vibrations in the back of my mind.

I tried a bunch of ways of securing the little reed switch. In the end KISS one. If it needs replacing one day I’ll just epoxy on another one. No tiny screws to undo.  I spend quite some time getting that opening dialed in. Its pretty close to the area size of the RAM air opening so I am VERY confident its big enough to supply air to the engine at WOT.

Here we are with everything in place for final testing.

As you can see it works and I added a view of the engine as well. This little video had 13,000 views on Facebook 21/1/24. Probably a lot more by now. Airplane guys had a lot of comments too. I thought an alt air door was pretty standard? I just don’t have room for another mechanical cable in the cockpit so maybe the fact its electric is of interest.

It works…on to the next thing.