Center Section – Page 5

Center Section/Seat Substructure Done

Posted on September 20, 2014 by Michael — No Comments ↓

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!

Center Section Work

Posted on September 14, 2014 by Michael — No Comments ↓

Time: 5 Hours

The center section has a forward half and an aft half that will eventually be joined to make a pocket for the wing spars. On each side there are 2 bulkheads one forward and aft. I deburred the edges and all the holes in each of them. On the left side there are several nutplates that needed countersinking as well. I got that work done yesterday after a pretty good day of house hunting. My girl, which works for the same company, got the approval to transfer to Chicago! So we are pretty excited to get a new and larger home to share together. A lot if nice houses out there, my wish list….a large garage for the aircraft build. Hers….nice kitchen and master bath. We found a few and hope to make an offer soon. So today I got back at the center section. First was to prime and paint the 4 side bulkheads.

I then riveted the 4 nutplates to the forward center section, these will eventually hold 4 adel clamps for the fuel line.

Several other parts get riveted to the center section including the forward seat supports and seat ramp supports. I match drilled all the holes and enlarged the ones that will have a AN3 bolt in them.

There are 2 vertical support filler pieces that are anodized as well. I reamed them to the final size of 1/4″.

There will be one rivet that holds the side bulkheads in place that will interfere with these vertical supports. So you need to countersink it so that you can put a flush rivet there so the support will sit flush on top of it.

I then scuffed to supports and deburred all the edges/holes for priming.

Since I’m going to have to wait several days before riveting these parts as the paint drys I looked aged in the plans for the next steps. The next phase will be the seat rib assembly section. So I spent some time looking for and locating every part for this substructure in between primer coats on the other parts.

After the primer was dry I riveted the nutplates to the seat support angles and ramps. I also painted them so if any part does show after assembled they will look good.

That’s where I called it a night, I have a light flight schedule this wee so I’m hoping to get some good building in.

Center Section Starts

Posted on September 8, 2014 by Michael — No Comments ↓

Time: 4 Hours

I was able to get some time in the Hangar tonight starting on the center section. This part of the fuselage is the mating section to the wing main spars. It comes from the factory precision matched to the spars I have and most if it is assembled and anodized. But there is some building and assembly that remains. You start with drilling the rudder cable pass thru holes in the web. You have to double check the plans as there are 2 different spots where to drill dependent on if you are going tail dragged or tricycle gear. Once I was happy with the read on the plans I marked the correct holes and drilled with my unibit.

Working with this section is like working with the main spars, you don’t want to screw up as these would be very expensive to replace and they are matched to each other already. I just read and read and read the plans before doing any work. Next steps were to create some seat belt spacers out if 5/16″ tubing.

I then debured the edges of the seat belt attach lugs.

The forward flight control has a mounting bracket that gets attached to the forward side of the center section. You have to fabricate this out of some angle stock using the dimensions from the plans.

With the one attach hole drilled in the bracket you can bolt it to the center section and match drill the other using the second hole already in the center section after squaring everything up.

On both ends of the center section there are a forward and aft bulkhead. I needed to flute the flanges to get them to lay flat, just be sure to read the plans as there are certain spots that can’t be fluted and the flange must be flat.

You can then bolt and clecko the forward bulkheads to match drill the 1/8″ holes.

I did several other small tasks like match drill for several nutplates and countersunk for their rivets. That’s where I called it a night. I did look over the painted parts from this weekend and I’m still happy with their look. They should be ready for riveting this weekend.