Roll Bar & Tail Spring Work

Time: 8 Hours

Today I asked my builder friend Glen to stop by and help me move the fuselage from the workbench over to a couple of sawhorses. This would allow me access to the center section rivet holes that are in common with the forward bottom skin, left mid bottom skin and right mid bottom skin so that I could final ream them.

I then moved up to the pilot seat back roll bar. To install it I removed the cockpit rails and slid it into place and returned the rails. I have read several builders sites and also researched this part on the www.vansairforce.com forum. There are 4 holes that you have to drill up from the bottom of the steal flange up thru the spacer and finally the rail. What builders have found is that even though the roll bar is clecko’d to the support pates in the side wall it doesn’t ensure that the bar legs are flush with the rail/longeron area. What this means is that as you drill up you have the chance to drill closer to the inboard edge of the rail/spacer causing an edge distance issue. Some have had to replace several of these parts for this error. The hole is right on the edge of having an edge distance issue as it sits normally so any movement of the rail/longeron outward will make it worse. So the cure is to clamp the section tight so as you drill up you hit the right spot. So I grabbed 4 of my bar clamps and squeezed the parts as tight as I could get them. I was able to go as far as the rail would let me as it eventually hit the roll bar.

IMG_4942.JPGOnce I really happy with the fit I match drilled the two center holes down thru the rail and thru the roll bar leg. I clecko’d as I went to hold everything in place. Then I used my 12″ drill bit to drill up thru the other holes. I was happy to see that the edge distance was fine.

IMG_4944.JPGI finished up the remaining holes and set everything in place.

There are 2 screws that will hold down this roll bar on each leg and they needed to be drilled to a #19 for the AN509-8R8 screws. I first marked the required holes and then drilled with a #21 first and final sized to a #19.

IMG_4949.JPGI did some final drilling on several spots like the center section bulkhead caps and tail inspection panel nutplates. I then moved to the tail wheel spring mount. This steal tube assembly will hold the steal rod that holds the tail wheel. I had already drilled it to the aft most bulkhead earlier in in the tail build. Now I needed to create a shim for where the mount hits the next forward bulkhead. The space can vary and just needs to be filled. What I did was to put the mount in place so I could eyeball how think of shim I needed. I used the mount to trace the outline for the shim.

In these next three photos you can see the area to the right side where the shim goes between the mount and the bulkhead. The plans have you look down the tube from the back and sight in the spacing by looking at a small tooling hole in the bulkhead. I just lined it up so the hole was in the center as best as I could tell.

Once it set and clamped in place I drilled 2 holes thru the bulkhead holes into the spacer and the mount. Those will get enlarged later for bolts. This mount now angles down as it goes aft and descends below the bottom skin line at the aft end. For this Van’s gives you a template to remove some of the skin. I transferred the template to a piece of paper and placed it in the skin to mark. I took it to the bandsaw and made the first cut after drilling a hole at the leading edge of the tracing.

What I found was that this cut was a little narrow and hits the welding of the mount so I will need to remove a little more.

That was another 8 hours in the Hangar and a great weekend of building. I cleaned up shop, put the tools away vacuumed up all the aluminum shavings from the day. I have a fairly busy schedule this week but should be able to get some time building in.

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