Air Intake mods - More Sawsall Art

I continue to plug away at programming the EC3 and things are getting better. The mixture plot is getting smoother and the engine is running better.


I have a fifth fuel injector, which is used as a back-up, but it barely ran. I found that it was over-sized, capable of delivering 87 lbs. of fuel/hour and the mixture was extremely rich. This seems to be out of the adjustment range of the EC3 so I ordered a 55 lb./hr. injector. It will be here next week, so in the meantime I am holding off on tuning the engine and will tend to a few other items on the list.

All along, I have been planning a radical change to my combustion air intake. This was successfully accomplished by Harry Hinckley and Greg Zimmerman in Greg's FAST Swearingen SX300. There will be a little scoop in each plenum snout. This air will be directed, through two hard tubes, to the throttle body. Here is a photo of the mock-up I made last year. I have since made the pipes, now I just need to get the scoops placed in the plenum.


As usual, I start with pouring in 2-part foam, held in place with paper dams & tape.


Then I get out my favorite shop tool; Mr. Sawsall:

I use the 14" saw blade to gently remove some of the foam I didn't want.

After rough trimming, I attached a couple of pieces of hard foam, using 2-part foam as glue. The hard foam will make a better foundation for the lip of the scoop. Some wire pins hold the hard foam in place while the 2-part expands.

Since it's cool in the hangar, I'll wait a day before I get into the detail carving.

This may all seem hare-brained, but what the heck. That's what experimental aviation is all about.