Wed Feb 24 2021

Cutting canopy latch slots

I didn't really want to cut this template out of my plans, so instead, I just took measurements of where to drill the ends of the two slots.

Laid out the drilling locations.

Slot ends drilled. I didn't use a center punch to locate the centers, so my 1/16" starter drill drifted somewhat. No worries, I just used a needle file on one side of the hole to bring the center back into position before drilling up to #40, then #30.

Van's instructs to file these slots between the two end holes. That'll work, but seemed like a lot of effort. I decided to use a cutting disc in my 90 degree die grinder to hasten the progress. I laid three layers of masking tape all around to provide some insurance against a mishap.

Only took a couuple minutes to slot through. Of course, the slot will need to be widened. It's currently only a blade thickness wide...about 1/16".

The filing went reasonably well with the starter slot, but still took a while.

Most filing completed...just needs some cleanup and filed to the correct width.

I didn't have a wide file that was sufficiently thin to fit through the slot, so I taped a piece of sandpaper to a strip of aluminum. This worked well.

For filing the corners of the slots square, I decided to grind a safe edge on my square needle idea I got from the Clickspring channel on YouTube.

One side of the file is now smooth. It makes it easy to file into a corner while being confident that I don't inadvertently file the adjacent side.

Like so.

After much sanding, filing, checking, rinse, repeat, ad. infinitum, the slots were done.

Test fitted the latch assembly. Weird thing is that at the aft end, the latch handle wasn't flush with the outside of the skin. I know I laid that out correctly and even used a scrap of .032 thick skin to set the offset.

Ahh, I see...the fuselage is slightly curved here. So, the top and bottom angles are only contacting the skin at the forward and aft ends. It's weird that Van's does it this way... the skin will be deformed when it's riveted to the angles. I'm thinking this can be done better.

There we go...used the shrinker to curve the angles a bit to match the curvature of the fuselage side skin.

Okay, so now the angles match the inside surface of the side skin quite nicely, but since they are now slightly curved, the latch handle sticks out a bit.

So, I just sanded and filed that latch handle down to match the curvature of the angles, while still keeping the .032 offset. Quite pleased with how this is coming out. Tomorrow, I might widen the slot a few thousandths to accomodate paint. As it is now, it's only about .005 wider than the latch handle itself.