Center Section/Seat Substructure Done

Time: 8 Hours

Another great day in the Hangar today. We had beautiful weather here in Chicago which made for a nice day with the door open. After doing some research last night and consulting with my buddy Glen I increased the space between the center section to 1.440″ to give that extra little bit of room for the eventual wing spar attachment. I also abandoned the PVC spacer idea in favor of using the bolts and several nuts to maintain the space. I did this as it was just going to be easier to get the space just right as I adjusted things.

Once I had all 8 bolts in I riveted the flange and the flange nutplates. I taped off the ones that don’t get riveted now so I would have to drill out rivets later.

That basically completes the center section, the only step left was to install the snap bushings to protect items that will travel through the section.

I set the center section as side to start the assembly of the seat substructure. When I ordered the fuselage kit I forgot to order the electric trim option so I made that order this week and it arrived on Friday. That was the first task at hand with this section. It’s funny that Van’s has this kit that has instructions and plan drawings from 1998 and now have totally different parts for the seat ribs. Back then you have to measure and use a template to cut holes for this trim kit. Now the ribs come pre-cut for it, so you have to do a little interpretation to figure things out. Once I did just that I had the 2 brackets, one for holding the trim servo and the other a pin guide, in place I match drilled all the holes.

A little time cleaning up all the edges and holes and off to the primer table.

While the primer was drying I moved on the the assembly and riveting. First up was the bulkhead and the 2 rear spar attach doublers along with the seatbelt attach point and corner gussets.

I riveted the nutplate’s on the rib angles next.

At this point you rivet all the parts for the 2 forward inboard ribs. They get the rib angle, the seat belt side attach points and a small bracket.

At this point the plans have you systematically add all the parts and rivet as you go. I was able to get some with the squeezer but moved to the double offset head for the rivet gun and my tungsten bucking bar.

I didn’t have to drill out any rivets in this section. I did however have the gun bounce off the rivet head and make a mark on the rib when I was riveting the servo bracket but not too bad and a little touch up on the primer and all was good.

So I was on a roll even though I had 6 hours of solid work in. The next step is to flip the section over and put the two bottom skins on.

I used a sharpie to mark the holes that get skipped now for later riveting. I then started the riveting working as deep as my arms would reach.

I was able to reach all but about 19 rivets with it laying on its back.

I tried to back rivet the rest but only had access to a couple as the bulkhead was to tight. I left the back rivet tape on to hold the rivets in place and stood the whole structure in its aft end. That gave me access to the rivets and it would stand on its end to give me time to get the gun and bucking bar in place. Not the easiest task but it worked. I found that the rivet that was dead center in the bulkhead, on the skins, didn’t actually have a hole in the bulkhead flange but rather a slot cut into the flange. When I dimpled the skins that dimple now sat up a little as the slot wasn’t as wide as it needed to be. I didn’t catch this when the skins were match drill since the dimples were not done. So I drilled out that center rivet and went to a flush blind rivet. This allowed me to put a lot of pressure on the skin and rivet at the same time to get the skin to sit more flush. You don’t rivet the outboard ribs at this time so that’s as am far as I could go on the skins. I only had to drill out 2 rivets as the skins were a little bouncy causing the gun to slip a little.

I cleaned up the bottom of the skins and flipped it back over to put it in its place. The RV is starting to take shape and look like something.

Wow I really love days like these in the Hangar and you get to see real progress!

Seat Substructure/Center Section Work

Time: 8 Hours

I got an early start today in the Hangar so I could get some work done before our quarterly pilot and staff meeting this afternoon. First up was to scuff the bottom flanges of all the seat ribs. I try to do this before dimpling as the raised dimples tear apart the scotch-brite pads if I do it after. It just happened that I remembered to do it first this time. I then grabbed the pneumatic squeezer and dimpled all the flange holes.

Next up was to dimple the bottom skins. There are several rows that you don’t dimple at this time. I marked those with a red sharpie and grabbed my DRDT simpler and went to town.

With the dimpling done it was on to scuffing and cleaning all the parts. That was followed by priming.

There are a couple parts of this substructure that will be slightly visible in the cockpit. So I will finish paint them. Before I do I had to rivet the seat belt attach lugs together.

Now that I had all the seat substructure primed and painted I went back to the center section as the paint has had a week to cure. The one thing about the Rustoleum is that it can be worked with after around 5 days but it can be chipped still to get a real cure you need a month or so and it seems like it becomes hard as a rock. So still try to be careful as I can be when working with the painted pieces but I know I will have some touch up to do. I borrowed some bolts from my friend Glen that he used for this task. They have the treads ground off so you don’t damage the close tolerance holes of the spar center bars. They help align everything for riveting

I was able to get about half of the rivets with the pneumatic squeezer and did the others with gun and bucking bar.

That was the forward half I then moved on to the aft half. It was the same process as the forward except this side has the seat ramp and supports. I had to buck most of these as the squeezer wouldn’t reach.

Now was the time to mate the 2 halves together and match drill the top flanges. Van’s also instructs you to create a wood spacer that goes between the 2 halves to act as the wing spar. I have read several different builders websites on different spacers. My friend used 1/4″ bolts with several nuts and washers. I decided to try the PVC route. The space is called out in the plans as 1 7/16″ or 1.438″. I measured and cut the 3/4″ PVC to exactly 1.438″.

Once the spacers were in I match drilled all the holes followed by countersinking the nutplate holes. There were 3 extra holes in the bottom flange that were not in the top flange. They are for brackets that are part of the rear seat rudder pedals. The plan page from the rear rudder pedals show a nut plate that has 2 rivets on the same side. The holes in the bottom flange are for a K1000-8 nutplate which has the standard left and right wings. I drilled the top flange using the bottom as a guide. I then enlarged the middle hole to a #19 that will allow a #8 screw to go through.

Before putting the halves together put torque seal on the bolts in the forward section.

As you put the halves back together you can insert the forward control mount, seat belt lug and the 2 spacers. It takes a little time to get all the parts to line up so you can insert the bolt.

I decided that instead of just 2 spacers per end I would use 4 per end. I will make 4 more tomorrow.

That’s where I decided to call it a night. That was a good 8 hours of work in the Hangar!

Seat Substructure Deburring

Time: 8 Hours

The painful task of deburring every edge, hole and slot began. I just pull up my stool, turn on the TV and get at it. I take a lot if breaks to keep the work manageable. I didn’t take any photos today as they still look like a bunch of ribs laying in a pile. 8 hours of deburring, sanding and filing to get every edge and hole just right. I have aluminum dust all over me and I’m tired and ready for a shower. The good news is I’m done with that task, tomorrow I start dimpling, scuffing and priming. Some of these parts will get pair as they will show a little, mainly the seat belt attach points. Another good day in the Hangar.

Seat Substructure

Time: 8 Hours

While I’m waiting for the center section painted parts to cure for a few days I moved ahead in the plans to the next section, the seat rib assembly. This is the section that will eventually support both the pilots and passengers seat structure. This step just continues the progress from the firewall to the tail build process. First up was to create 2 spacers out of stock that will evenly space the rear spar attach points for the rear spar of the wings.

There are 2 seat rib angles that have 10 nutplates that needed countersinking for flush rivets.

2 brackets needed to be fabricated from some 3/4″x3/4″ angle. Luckily I remember reading during some research that these pieces need to be cut from the 12′ sections that came with my wing kit a year ago. They came with them since they are so long and could fit in the wing spar boxes. I triple checked the fuselage plans to make sure I had the right pars for the longerons, the angle pieces that will run uninterrupted from the firewall to the tail. They are not expensive but shipping would be due to their lengths. Once I was sure I cut 2 1/8″ pieces, one from each piece of 12′, to minimize the effects of a bad decision here. Then I fabricated them per the plans.

With one hole drilled in the bracket you can match drill the second using the rib as a guide.

I then match drilled all the 1/8″ holes on each of the inner rib structures with the seat belt attach points.

The 2 outboard aft seat structure ribs needed to have a little modification done to the forward part of its flange to make room for the flange of the next rib inward due to the angles the 2 ribs sit at.

Now you can clecko all 10 ribs to the rear spar attach bulkhead to match drill all the common holes.

I grabbed my 2 sawhorses and placed the seat rib assembly upside down on them. This allowed the curve of the bottom to show as the top of the ribs are laying flat on the sawhorses.

This allows you to lay the bottom skin down on the substructure to get the curve right by fluting the flange of the skin. This way the skin matches the curve of the rib.

I then clecko’d both skins to the substructure to match drill all the 3/32″ holes.

I edge rolled the right bottom skin where it overlaps the left skin so that it will sit tight after riveting. I also edge rolled the outside edges of the aft ends of both sides where they will over lap the curved side skins later in the build.

I disassembled all the parts and now the fun deburring begins on all the edges, lightening holes and rivet holes.

I did a little deburring on a few parts and decided to call it a day.