Finishing Kit

June 21, 2011

Canopy Frame and Release Mechanism - continued - 6.5 hrs.

Today, after coming to grips with the fact that I can't procrastinate any further, I tackled the issue of completing the drilling of the holes in the hinge arms. Not being able to use a drill press and clamp everything down securely, I had some concerns about getting this done properly. The solution actually turned out to be pretty simple. The hinge arm was simply rested on top of my workbench, and the drill block that I made clamped down onto it. With one hand on the drill, and the other hand holding the canopy frame, this was actually quite satisfactory. As far as drilling the hole to size, the best thing I found was my unibit. It's self-piloting, after all, so I don't have to worry about the hole staying centered where I want it. And it works so smoothly to enlarge the hole in small steps. I don't know why I didn't consider it sooner. So I drilled from 1/4" to 9/32" to 5/16" to 22/32" and stopped there. The next graduation was the full 3/8" and the step on the unibit isn't long enough to go all the way through this thick hinge arm. So as you can see below, I switched to my 23/64" bit for the next step. Then I used my 3/8" reamer to finish the hole to full size.

Wash, rinse, and repeat for the other side, and then it's time to press the brass bearings into place. This was a cinch and only took a few minutes with my squeezer. I'm very happy to finally have this done.

Now, as anxious as I was to put the canopy frame back in the plane, I first took the time necessary to finish the release mechanism. After figuring out the orientation placement of the WD-618 lever arm that I want, I drilled holes through it and through the shaft of the WD-619 and then opened up a hole in the hat channel for clearance of the bolt head as it swings through. Time consuming little details, but nothing difficult about it. I wanted the lever arm in place before putting the top skin back on, so I can easily reach in through the firewall opening and work the mechanism. Seen below, the whole assembly is back in place and ready to use. Note that the lever arm of the WD-618 sits right under the middle rib when the canopy will be closed. I placed it here in this orientation for a reason. In the normal Vans installation, this lever arm is attached to the canopy release handle that comes out through the instrument panel, which is held tightly in place with a stiff spring. You have to pull against this spring to release the canopy. In other words, there's no chance of the canopy release wiggling loose from all the vibrations during flight and surprising you with an unexpected release of the canopy. Yikes! That's a surprise I don't want! This was brilliant engineering on Vans' part. But if you are doing things this way, it's wise, I think, to consider a way to make sure this mechanism won't wiggle loose. The odds are probably slim, but I prefer zero. What's to secure it in place, if the canopy release handle is going straight down? Could it ever wiggle open during flight? Probably not, but still, I drilled a 1/16" hole in the lower flange of the center rib, right over the top of the hole in the end of the lever arm of the WD-618, so I can safety wire it in place once the canopy is installed for flight. I'm going to get my tech counselor's opinion on this on his next visit here, but that's my current thinking. It's just peace of mind.

In spite of all this work, I'm still not finished with the release mechanism. I've yet to rig the release handle and a way to secure it in place. But that can wait. Summer weather is coming soon and I want to be ready to cut the canopy if it ever warms up around here. So with the release finished to this point, I was finally able to install the canopy frame and see it go smoothly up and down. Cool!

Here's a shot from another angle. Now it's time to put the forward top skin back on and check for clearance.

I clecoed the top skin back on. I was able after this, to get the canopy frame pushed down, but it won't come up again. I have clearance issues with the skins.

Here's why. After all is said and done and with a cleco in every hole, I did such a great job fitting all of this, there's no gap at all between the canopy frame skin and the top forward skin, on the left side as seen below. This is actually okay with me. I can easily file a bit away and control how much of a gap I end up with.

Now on the other hand, this is the gap l'm left with on the right side. I think this will be sufficient. It's not as big as it looks in this picture.

I'll tackle this stuff next time. That's where I left off for this session. This has been quite a day. Lots of time spent on details, but I feel like I'm moving forward and things are being accomplished.

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