Today was all about finishing up the canopy external lock install.  Clearly I hacked my way through the physical install of the lock into the fuselage sidewall yesterday, so today was all about getting a slot cut in the CORRECT spot on the bottom surface of the canopy latch handle which is of course what the lock latch is rotating up into to make a physical block from opening the handle.

I used the two 3D printed handles that I’ve been using for years in the canopy handle assembly as test subjects to get the exact position of the canopy external lock interfacing slot in the handle dialed in.

Once I was confident of the required lock latch slot position on the canopy handle, I just need to load up those numbers into my Fusion 360 CAM, post process and get to machining it… right?  Yeah, well, I had niggling issues galore that turned a 30 minute task into a 2+ hour long task in figuring out some very frustrating idiosyncrasies of Fusion 360 in trying to do a 3-tool machining job.  But I powered through and finally came out victorious… yay.

My first task on the mill was to simply clear out some of the material, especially since the 1/8″ end mill that I had planned to use on this 1/8″ wide (or high…) slot was causing all kinds of angst in Fusion 360.  Using a 1/16″ end mill made all the errors and warnings go away inside the CAM program, but I didn’t want to stress this diminutive end mill too much.  Thus the row of 0.118″ diameter clearance holes, prepped for drilling with a center drill (pic 1), then the actually drilling (pic 2).

I then used the 1/16″ end mill to clean out the slot… the whole machining of the slot taking less than 10% of the time to program it all! (sigh)

And here we have the slot.  I did angle the forward (left) end with the Dremel to allow clearance of the incoming and exiting lock latch as it pivots into/out of the slot.

With a number of test runs on the actual canopy handle, installed in place, which did require a minute amount of judicious filing, I was happy with the combined, integrated fit and operation of the lock and handle together.  I removed the handle assemble and created a taped up stir stick dam to contain micro to fill in the aft area that I had opened up in the side wall to mount the canopy external lock.

I then whipped up the micro, filled the aft area and finished off this task with a small piece of peel ply to smooth out the top.

I thought I’d grab a shot of the hole that I made on the inboard sidewall to first allow for using my hex key to install the washers and screw to secure the pivoting latch plate to the lock barrel.  Since I can see it in this pic, I’ll also note that I removed about 0.05″ of the top of the latch plate to flatten it and keep it from travelling too far up into the handle and digging into the forward pivot rod.

Back to the screw… if I had planned well enough ahead, I would have simply drilled out this hole in the inside sidewall wide enough to allow full insertion of the screw.  As it was though, I had literally ground down a good 0.035″ of the head of the screw in my attempt to get enough clearance.  I also used a razor knife to make the hole in the sidewall a big enough diameter to allow the screw to not be pushing on the sidewall AFTER the lock was installed.  My point here is that I made two things ugly (screw and hole) by trying to install this the “right” way… good deeds never go unpunished!

Besides slathering up the front edge of the aft nose cover with micro, I failed to mention (as I often do) that I did a small 3-ply stepped layup on the front face of the left inboard elevator fairing to close up a gap between it and the canard trailing edge (lower right corner of pic).  I then micro’d that when I micro’d the cover’s front edge.  Well, I sanded that front face micro down before installing the cover, and although I don’t have a comparative “before” pic, you can clearly see that the gap is minimal.

Tomorrow I’ll finish filling in the cleared out inside sidewall for the canopy external lock install and then move onto finishing the nose, etc.