Canopy Frame (3)

Next up was the top strap, which is attached just like the bottom one.  It wasn't all that hard to do, but very time consuming.  Once both straps are in place, the front side roll bar U channels slide over them to close out the roll bar box.  Just like the aft portion, I had to file down the ends until they mated together in the middle.

The finished roll bar is supposed to be 1 1/2" deep when all put together.  I cut a number of 2x4 chunks to 1 3/8" (subtracted the 1/16" material for each channel) to put inside the channel so I could clamp it all together and keep it the right size when drilling the front channel to the straps.

I had heard that these roll bar channels tend to be pretty rough in terms of the size of the flanges.  In some areas the flanges are nice and parallel, and in others they look like a drunk sailor made them.

It's easy to see how much variation there is when the tape is lined up to the flange edges.  There's not much I can do to fix it.  Even though the flanges are all over the place, the important thing is that the roll bar depth is correct, which it is.  In order to maintain edge distance, the rivet lines will have to wander with the flange edges as well, but once painted I don't think the rivets themselves will be that noticeable.  I'll have to think about whether or not I want to fill the gap itself prior to painting though.

A lot of drilling later, the whole assembly was finished!  The front side middle splice plate will be riveted inside the channel, but I put it on the outside to drill it in place.  It's amazing how beefy this structure is once it's put together.  The last thing I did was stand it up and measure the height at the middle.  It was still about 1/16" too tall, so I filed down the legs.  The last step will be to re-drill all of the holes to #30, but that's for another day.

Canopy Frame (2)

The roll bar has to be the right width and height once it's all assembled.  I measured the fuselage width and subtracted the width of the two brackets that attach to the outside of the roll bar.  This gives the width that the roll bar itself has to be.  After a quick look and realizing that the parts were going to take quite a bit of manipulating to make them fit right, I decided setting up a jig would be time well spent. I translated that measurement to a board and screwed down pieces of angle to act as stops.  I also attached blocks for the bottom portion, since aside from the width, the roll bar also has to be a specified height at the center.  It took a lot of back and forth, but filing about 1/8" from the center joint and giving the bottom edges a slight angle did the job.

With the width and height sorted out, I clamped everything down to keep it all flat.

I match drilled the center splice plate.

There are no pre-drilled holes in any of these parts.  The front and rear u channels get connected together with 1/16" thick lengths of aluminum that nest inside each flange.  I ground the corners of the 1/16" piece so it would set better into the curve of the flange.  I laid out the rivet spacing on lengths of tape, then put the tape on the flange (easier than marking the spacing out directly on the awkward curve of the roll bar).  The strap (not really a strap I suppose, but easier to just call it that) tends to lift up as it's drilled.  I clamped it in the center, drilled, clecoed, then moved the clamps and worked my way to the ends.  I started by drilling at #40.  Next I'll go back and upsize them to #30.

Canopy Frame

The bearing I ordered for the rudder hasn't arrived yet, so I'm moving on to other odds and ends while I wait for it.  I made the right side rudder stop and added it to the ever growing primer pile.

The canopy frame (roll bar) is up next.  It has a surprising number of parts.  I started by making all of the angle pieces that are used to connect the roll bar to the fuselage.  These things took forever!  Not only are the pieces made out of very thick material, they have angles designed in to get the roll bar geometry right.

The roll bar halves get riveted together with plates.  I laid out one plate, then clamped the second one onto it and drilled them together using the drill press.  I undersized the holes for now.  Once I fit them in place with the roll bar I will drill to #30 in place.

The canopy frame is made up of 4 pieces - 2 back halves and 2 front halves.  They're made out of pretty thick material that isn't perfectly flat.  Since it can't be fluted to flatten it, I'll clamp it down to a flat board while I build it all.

Vertical Stabilizer

It feels like it's been forever since I've spent much time working on the plane.  I got back to working on the vertical stab today.  After measuring over and over, I felt like I had it located correctly, so it was time to drill.  I clamped it in place and drilled the first few holes for bolts in the rear spar.

The bracket that the front spar rivets to (the bracket gets bolted to the front horizontal spar - it's the blue piece in the picture above) can cause some warping of the rear spear, just depending on exact measurements things were built to.  If the front vertical spar sets on the front side of the bracket, it can warp the rear spar in one direction, and if it sets on the back side of the bracket, it can warp it in the other direction.  The instructions say it's supposed to go on the front side of the bracket, but provide a lot of options for shims and other solutions to get the rear spar straight.  To test the rear spar, I put a straight edge across all 3 of the rudder hinge brackets.  They should all line up if the spar is straight.  With the front spar on the front side of the attach bracket, the middle hinge is about 1/16" forward of the top and bottom ones.  I swapped the front spar to the back of the attach bracket, but that reversed the warp significantly.  So I need the spar attached to the front side.  I may end up making a thing shim to go in between the pieces and push the front spar forward just a tiny, tiny amount and see if that makes the hinges line up perfectly.  Before I do that, I'm going to put the rudder on and see if it even matters.  The hinges need to line up so the rudder can swing freely.  Each hinge attaches to the rudder with a bearing, just like the elevators do.  That means I can move the bearings in/out to line up with the hinge holes.  The question is will moving the middle bearing 1/16" forward cause the rudder to bind.  I'll just have to play with it and see.

I went ahead and drilled all of the holes for the front spar and attach bracket rivets.  I won't rivet this together until I take the vertical stab off again.

I can't remember if I showed this before or not, but I had made the elevator control horn stop last time.  I match drilled it to the vertical stab rear spar, aft deck and longerons and temporarily bolted it in place.

The bottom of the rear spar is attached to the aft most bulkhead with 4 bolts.  I drilled those holes and put a couple of bolts in to hold it all together while I work on the rudder fit.  I don't know why the plans don't call it out earlier, but the bottom hinge gets two additional rivets as well. Why it didn't show those during the initial VS build is beyond me.  I can't put them in until I take the VS back off.

I was going to mount the rudder to the VS, but it looks like I am missing one of the bearings.  I have 3, but they are all the same size.  I need two short ones, plus one long one for the bottom hinge (due to the geometry, each bearing sets at a different distance).  I must not have caught the difference when doing my inventory years ago.  I saw the right number of bearings and figured they were the right sizes.  So yet another order placed to Van's!  Expensive little buggers - $25 for a single bearing.

I fabricated the left rudder stop and drilled it in place.