Drilled wing aft spars

April 29, 2016 – What a day this was! Myself and a helpful crew got the wing drilling done.

This had to be the warmest day of Spring so far this year, and I was feeling it by the time we were done.

I moved the fuselage and the wing cradle out into the driveway. We removed the flaps to help give access to the aft spar for drilling. We then slid the wings into position. It kinda looked sad with the wings there but without the wing bolts installed.

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We ground the threads off four hardware store bolts, and put them into place.

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Looks much better with some dihedral…

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We did have to trim the ends of the aft spars, and the forward strap of the center section “forks” to get the wings straight.

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We leveled the fuselage laterally and longitudinally, then hung four plumb bobs on the leading edges, then snapped a chalk line on the driveway. We lined up the inboard plumb bobs on the chalk line, then started working on getting the outboard ends perpendicular. Both wings had a very slight forward sweep.

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We measured from the outboard aft corner of each wing back to the upper corner of the side skin at the aft-most bulkhead. Got 173 5/8″ on each side.

We then used a level and a 3″ block to measure level on each wing. Some minor adjustments were needed, but we got it dialed in.

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I then got down into position at the aft spar to drill. I had made a nice wood block with a drill bushing in order to get a straight perpendicular hole. We realized that we couldn’t keep the spar clamped AND have the block in place. I decided to do it by hand. I started with a #30, then stepped up to #21, then used reamers to .191″, .250″, and finally .312″. And a lot of Boelube… The bolts slipped in great and were nice and straight. Those of you who know will think that the bolt is in backwards in the photo below. I just slipped the bolt in to test fit. I had to take everything back apart because I’m still in the garage.

Here’s the before and after at the aft spar:

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And here’s the proud daddy:

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Time: 24:00 (total man-hours)

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Installing trailing edge fairings

June 8, 2011 – I’ve deburred, cleaned, primed and installed the aileron gap fairings and the left flap brace. It’s been hot here, so I try to get done what I can as early as possible, and I’ve been quitting around 1 pm.

On the right wing, I realized that I still had to install the five rivets in the skin at the very inboard end at the aft spar, where there is the buildup for the spar attach. So Joe came over and we knocked those out. Now I can install the right flap brace, and then I can start on the ailerons.

On a side note, I found an ad on Vans Air Force for a tail strobe for $60. I jumped on that. Now all I need is a steal on a pitot tube.

Time: 6:05

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Attached aileron hinge brackets

June 4, 2011 – Well, the date is misleading, but the work goes on. When I was ready to do this update last week, my hard drive died, so I haven’t been able to do this until now.

I finished the aileron hinge brackets and riveted them to the aft spar on both wings.

In the previous post, I had painted all the parts for the hinges. I assembled each bracket on the table.

Then I clecoed each one to its respective position. The outboard hinges also get riveted to the outboard ribs, so I drilled and deburred those holes, then clecoed them in place. In my constant effort to go overboard, I used sealant when assembling the brackets, and when installing them on the spar.

I then riveted all the hinges.

The next step is to install the flap braces and aileron gap fairings.

The flap braces get trimmed where they fit over the doublers at the inboard end of the spar. There are guide holes in the parts, where you remove that small section of material.

I then cut both flap braces on those lines.

I test-fitted the four pieces on the aft spars. I’ll remove and clean them up this week.

Time: 4:55

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Riveted left wing top skin to aft spar

May 2, 2011 – I riveted most of the left wing top skins to the aft spar. Easy riveting except for one location.

At the very inboard end of the spar is the doubler buildup for attachment to the fuselage. The tickness of the structure there is making it difficult to get quality shop heads for the five or so rivets at that location.

Otherwise, the rest of the wing looks good, and I’ll move it to the cradle after the landing light is done.

Time: 1:30

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Began install of right leading edge

March 29, 2011 – I started installing the right leading edge to the main spar. The plans call for solid rivets for the rib/spar install, but access to shoot them is something of a challenge, so many people use pop rivets. I really didn’t want to do that, so I decided to use hi-locks, a fastener that theoretically only requires access to one side. Hi-locks are fasteners made of either steel or titanium that are secured with a collar that has wrenching flats that break off at the correct torque. I wanted to install them from the forward side of the spar so that I could install the collars on the aft side where I had room to work. They would also be easier to remove should the highly unlikely need arise. As it turns out, there wasn’t enough room to get a wrench or socket on the collars from the aft side, because they were up against the main ribs. So I drove the fasteners in from the aft side and installed the collars on the forward side. I used -5 fasteners, so I had to enlarge the holes in the spar and the ribs to #21. That drill size also allows for an interference fit of the hi-lock.

Did I gain anything from using these over pop rivets or solids? Probably not. I ended up having to modify my pop riveter for the tank z-angles anyway.

I still have to install the rivets for the leading edge skin and the main spar.

Time: 3:45

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Miscellaneous leading edge items

December 18, 2010 – I am at the point of assembling the leading edge skins to the ribs, and I quickly realized that I’d rather not do this alone. So I’ve done a couple of other odds and ends.

I assembled the stall warning switch that goes in the left leading edge.

I have the rib installed in the skin of the leading edge, and I’ll install the switch later. That way the vane won’t get damaged.

I also took the time to countersink the rest of the holes in the main spar that will accommodate the dimples for the leading edges. So all the holes in the spar are now countersunk, and I can paint that face of the spar cap on each side before anything gets permanently installed.

Time: 1:55

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Catching up on the right wing

November 18, 2010 – Today I took care of several items that would get the right wing caught up to the left.

I started by riveting the ribs to the main spar in the upper (forward) holes that will be under the fuel tank skin when it is installed. I couldn’t find these referenced anywhere in the plans, and I have seen them mentioned on other sites, so I went ahead and installed them.

The large countersinks are for the fuel tank screws, and the line of holes below them areĀ  the skin rivet holes.

I also had to dimple the holes in the aft spar.

I continued to dimple the main skins for the right wing. I got the wingwalk doubler and the outboard lower skin done. All I lack is the outboard upper skin. When that is dimpled, I can cleco it in place, and then I should be able to start on the leading edges.

Time: 3:10

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New wing stand and right wing assembly

November 17. 2010 – I’ve decided that in order to do the leading edges efficiently I would need to build a second wing stand so I can work both wings at the same time. I copied the structure of the stand that I have that I got from Kenny Haberstroh. I’m not the best with wood, but I think this will work.

After I got the stand built, I pulled out the parts for the right wing, and assembled the main ribs to the spars. This went pretty quick, since I’d done it before.

I then hung the right wing to the new stand. Things are a little tight, but I think I’ll just slide the stand over a little bit when I have to work on it.

Time: 2:35

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Deburred and dimpled right wing ribs

October 24, 2010 – I finally finished deburring and then dimpling the main ribs for the right wing. I also needed to dimple the aft spar for the left wing which is on the stand.

Now I just need to clean, alodine and prime the ribs, then I’ll put them away for the time being and go back to the left wing.

I also ordered the kits for the landing lights, since they will be built in to the leading edges. I went with the Duckworks original rectangular 55W light kits.

Total Time: 2:30

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Assembled left wing main structure

October 18, 2010 – I finished riveting the main ribs to the left wing main spar, then I attached the aft spar.

When the ribs were attached to the main spar, I set the wing up on the spar, clecoed the aft spar in place, and taped off the rivet holes that other items will attach to.

I was able to use the squeezer on most of the rivets through the aft spar, but it wouldn’t squeeze the rivets at the inboard end because that material has several layers and is thick. So I shot those rivets. I also was working alone, and wasn’t comfortable using an offset rivet set by myself, so I shot the rivets with the manufactured heads going in through the thicker material. Not ideal, but I didn’t have any problems with the thinner rib material not seating.

The left wing main structure is now complete. I’ll hang it on the stand, and start deburring and prepping the right wing main ribs for paint.

Total Time: 2:15

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Began left wing assembly

October 14, 2010 – I decided last night to start painting ribs for the left wing, because the breeze died down a little bit. So I got half of the ribs done then, and I painted the other half this morning.

While letting the ribs cure a little bit, I countersunk the holes in the main spar where the skin dimples will fit.

I set up the left main spar on my table and started riveting the ribs in place.

I put tape along the edge of the spar reinforcement to protect it from the bucking bar. Then I poked a hole in my finger using a knife to trim some tape on my bucking bar. Oh, I also got a blood blister on another finger from the main spar countersinking.

I started installing the ribs in the middle of the wing, so I could work out to each end. Shooting the rivets from the rib side, since it’s the thinner material.

Total Time: 1:45

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Rear Spar and ribs, continued

September 10, 2010 – Nice day today. I assembled the rear spars and did the preliminary fit of the left wing ribs and spars on the stand.

These three pictures show the three areas of the rear spar with the doublers attached. The open holes are where other parts will attach later.

I then clecoed the main ribs to the fwd spar and then clecoed the aft spar in place.

Here’s the left wing as it sits right now.

Total Time: 2:25

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Rear Spar and ribs

September 9, 2010 – I’ve continued the rear spar parts by cleaning, alodining and priming them. Today was sunny, but a bit humid after our storms. I got them primed anyway.

I also got the ribs straightened and fluted. I thought that pile would not disappear, and I got a blister for my trouble. I did all but the tank ribs. My concentration coming up will be to get the ribs ready for paint. Since I will not paint the tank parts, they can be fluted later on.

Total Time: 5:25

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Rear spar work

September 6, 2010 – A few days ago I started the doublers for the rear spar.

I located and drilled the center and outboard doublers that attach to the rear spar. These doublers reinforce the mounting of the aileron hinges. The center doubler has a hole that the control rod for the aileron passes through. That hole had to be transferred to the rear spar. I clamped and clecoed the doubler in place, traced the outline of the hole, and began by drilling starter holes with a unibit. I then used a rotary file in a die grinder, and finished up with a sanding drum on my Dremel.

I then located and drilled the holes for the doublers at the inboard end. Next part is deburring, cleaning and priming. I don’t think the weather will cooperate for the next few days. though.

After deburring the ribs, I’ll need to eventually get set up to drill them to the spars. So I decided to set up my wing stand. I got the stand from Kenny Haberstroh in Justin, and I had to figure out how he had set it up. After a phone call and some e-mailed pictures (Thanks, Kenny!), I got it set up.

Total Time: 3:10

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Installed tiedowns; Main Spar prep complete

September 1, 2010 – The tiedown brackets are installed.

I tapped the tiedown brackets per the drawings: 3/8″ x 16, 1″ deep. These holes will accept the tiedown rings that will secure the airplane in the event of high winds while parked.

I then drilled and installed the nutplates in the spacers and the tiedowns, then cleaned, primed, painted and installed.

On the aft side of the spar, using the nutplates installed in the tiedowns, are the brackets for the aileron bellcrank assembly.

I’ve set the main spars aside, and started on the aft spars. Doublers for the inboard ends of the aft spars get trimmed on the RV-7. Since the trim is the same on 4 pieces, I trimmed one per the drawing, then clecoed the 4 pieces together and trimmed the rest so they all match.

Total Time: 4:35

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Drilled tiedowns

August 29, 2010 – Today I decided to visit the therapist in the garage and drill the tiedown brackets.

The first thing you do is make lightening (reduce weight) holes in four spacers. I cut the material per the plans and used a spot-facer to make the center holes. The plans call for a 1″ hole. I didn’t have the means to make 1″ holes, so I made them 13/16″. I don’t think there’s a lot of edge distance for a 1″ hole. especially since you have to drill additional holes for nutplates.

The next step is to drill one hole in the tiedown bracket material at a specific location called for in the plans. You then bolt it to the spar and back-drill the remaining holes. I also drew lines along the backside of the brackets so I could make sure that it lined up when in place on the spar. Just look through the holes in the spar, and if you see the lines, you’re reasonably sure that the bracket is straight.

I then placed the spacers on the spar using carpet tape to hold them in place for drilling. The square is to ensure that they are even with the end of the spar doubler.

When everything is in place, you just drill through the existing holes in the spar to the brackets and the spacers.

Total Time: 1:40

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Spar nutplates complete

August 26, 2010 – It’s been a while since I’ve been able to do a good day’s work, so I got it out of my system.

Countersinking the holes for the tank attach nutplates was a bit intimidating, and I had a rough hole or two to get started, but once I got into it, the job kinda flowed on. After figuring out the settings for the countersinks, I drilled a plate with some holes to accept the pilot of the countersink to prevent chatter, then I drilled away.

Everything looks pretty good.

I then installed the nutplates for the tanks and for the access panels on the bottom of the wings, and the 1/4″ nutplates for the center section.

Total Time: 5:20

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Set up and ready to start…

August 24, 2010 – Well, we’re on the cusp of a break in the heat. Yesterday it was 107. Today a “cold” front is moving through, and tomorrow it will only be 90. It’s amazing how much we appreciate the small things when they’re not here.

Anyway, I finally got everything more or less in place, and I started on the spars. VERY intimidating because I don’t want to even know what one of these would cost to replace if I make a mistake. No wonder they’re anodized gold…

I started by labeling the spars as to which end is up, then I secured them in place on the table and began countersinking for the nutplates. I only got one side done on each spar. I guess I’m going to go with Van’s method for countersinking the screw holes that accept the dimples in the skin material. I’ll do that tomorrow when it’s cooler…

Total Time: 1:15

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