FAB, mixture arm, cowl

Worked on the mixture arm again.

Finished up fabrication on all the subcomponents for the subpanel. Then I primed all the parts, which takes a couple days to dry. I'll have to wait until then to rivet it all together.

Getting the throttle body to work has been a pain in the ass, to say the least. Van's calls the air intake a forward air box (FAB), and it attaches to the bottom of the throttle body. On the other end, the cowl has a snorkel that provides ram air. In the middle of the FAB, there is a filter like you would find in a car. Of course, this means it has to line up with the cowl. On top of that, the captive bolts that connect to the throttle body cannot interfere with the filter. On top of that, the levers and cables for the throttle and mixture have come from either side and can't hit the side of the FAB. On top of that, each cable and lever has to be aligned at a certain angle to give enough torque so that the throttle body can go through it's full range of motion. And on top of that, the fuel servo sits off center on the engine, so it is shifted to one side.

So, all this bitching and moaning is about the fact that there are a lot of variables to account for with the throttle body..and when you mess with one it messes up all the other ones too. The good news is I came up with a solution. First, put the cables and levers into place. Make sure they are aligned correctly so that the throttle can go from the full range from open to closed, and the mixture arm can go through the full range of rich to idle cutoff. Then, go get a clear piece of plexiglass and cut it into the same shape as the aluminum top that serves as the mount to the FAB/throttle servo.

This way, you can see where the filter is and avoid positioning the FAB where the bolts would hit the filter, while keeping clearance for the levers that operate the throttle and mixture.

Even with all this, I'm going to have to make a cutout in the cowl. The end of the bolt is less than 0.25 inches from the side of the cowl, so the solution is to cut out that section and make it balloon out a little. You can see the minimal clearance here

I also fitted on the cowl just for grins to see how it would fit. Not too bad, need to make a few adjustments so everything is square and symmetrical.

The next steps are to get the servo sorted out, figure out the cowl, then start busting out the avionics. After that the wings and tail will go on, and hopefully some flying!