Cold day in the garage with the air filter and a pile of aluminum bits. After a lot of careful measuring, I came up with a basic plan of attack, starting with making a new set of brackets. Then I bent a 90-degree flange on the front of the baffle, right at the forward edge of the air filter.
The filter butts up against the new flange at the front, and is held at the back by a piece of W-shaped bracket material. Actually it is more like VW shaped, since I had to put another bend in it to match the shape of the underside of the baffle.
I cut some new side brackets and clamped everything in place on the airplane:
Then I match drilled the side brackets to the inlet ramp baffle. Laying out the holes on the outboard side was challenging due to edge distance issues. The air filter is almost the same size as the inlet ramp!
Once all the brackets could be clecoed to the inlet ramp, I was able to reassemble the whole contraption on the workbench and see underneath. This is what it looks like on the bottom side:
I marked cut lines on the baffle, even with the edge of the filter on the sides and back, and somewhat back from the edge on the front face.
To do most of the cutting, I used a carbide grinding tool mounted in my drill press as a sort of crude milling machine, then followed up with files and scotchbrite. The hole has to be square at the back to admit the filter, but I left the corners round on the front side where the filter fits under the baffle overhang.
Here it is again for a round of test fitting:
The filter tucks under the front lip, then lays down into the cavity formed by the brackets. Of course it is just sitting in there, so I will have to build some kind of retaining device to keep it from falling out.
The air filter takes up pretty much the whole baffle, leaving no clearance between the baffle and the cowl. I marked a new trim line on the cowl:
I cut and sanded the cowl lip until I had an even 3/8" of clearance along the entire front edge of the inlet ramp. There isn't much cowl material left, but there should enough to attach the air seal material.
I don't have the air filter totally licked yet, but I think I am over the hump at last. Now that I know it is actually possible to make it fit – barely! – it's all detail work from here onwards.
