Fuse Side Skins

Chapter 29 - What A Beast!!!  I started this right after new years of 2020, and finished early July.  There was at least a couple week detour in there for getting some tunnel fuel lines done while they were more accessable.  Also got a new job.  So despite working from home because of the 'Rona, my work rate actually descreased.

Bending the longerons took some time.  I was lucky to find someone who would borrow me the bending dies that are no longer available for purchase.

Vans provides you a piece of Alcad that serves at the bending and drilling template.

 

You make a few long-edge cuts at an angle in an oak 2x4.  I paid $20 at Menards for a 4' board - not cheap.  Had to use some friends tools to get this done - a radial arm saw and table saw. 

Once you have your 2x4, then you use a bunch of clamps to start bending the skins.  This is probably the least fun step I've encountered in the build so far.  The skins are TOUGH.  If you don't equally bend and push, you'll crease the skins.  I did put a small crease in one of my front skins, but you have to look to see its there.  Vans should really think about bending these for you as part of the kit.

 

 Here is the rear skin bent up underneath.  Even clecos won't hold it tight.  But once you put a slight break in the edge (I think thats missing from plans) and rivet it, it sits nice and flush.

Once you get the skins bent and start slapping them on, you all of a sudden have something that looks like an airplane! Woa!

After drilling deburring and dimpling what feels 1 million holes, the whole works gets the primer treatment.  Then assembly starts.  On the two parts where the longerons meet the aft deck with brackets, don't stray from the instructions.  I did because I thought I was smarter and had to drill out a few rivets.  You'd think I'd know by now...NOPE.

This was a frustrating step - getting the firewall corner braces match drilled to the fwd fuse channels.  These are notorious for not lining up correctly, especially the upper left.  I swapped a few emails with Vans about it.  Basically you have to clamp the steel piece you are drilling to shove it deeper into the fuse channel so you get proper edge distance.  It seems like a lot of force, and I wasn't entirely comfortable with it.  But Vans said do it, so that's what I did.

See in this picture the first hole is nowhere close to proper edge distance.  Good thing I only drilled this one before discovering it.  To fix I clamped it in farther to get good edge distance on the remaining holes.  For the bad one I drilled a new hole nearby the bad one.

Here's a gotcha - make sure these nutplates get installed before riveting on the upper forward fuse channels.  You can see the bracket will make that impossible once they are on.

Riveting the skins took more help than any other step on the plane so far.  There are simply a bunch of them you just can't reach.  I also had to buy a few more odd rivet sets for my gun.  Nothing fancy or expensive, just different. My dad, neighbor Tracy, and even the wife (image that!) all pitched in to run the rivet gun while I bucked.

Once that huge job is done, the front floors go in.  The $15 Harbor Freight pneumatic blind riveter saved my bacon again here.  Notice that there is no sound insulation in here.  Many folks do, but for me that only serves to hold moisture and rot out an area that will be VERY difficult to access in the future. And add weight.  Everybody gets noise cancelling headsets in my plane, no need to carry weight beyond that.

Before floor install:

After floor install:

Putting the landing gear weldments in for the last time is satisfying too.  Those things are a beast with all the holes that never line up twice in a row. The plans have you making some tubing pieces with very specific length tolerances. I cut barely over then sanded down to get within a few .001"

Man it felt great to finish this chapter.  Really looking forward to getting a few things done with a little more instant(ish) gratification.

Fwd Fuse

She's really starting to look like an airplane.  Its at the point where you really start getting almost overwhelmed about trying to prepare for all the stuff you need to do. For example:

• I bought some 5052 tubing from spruce and bent my first brake lines
• Purchased the Andair duplex fuel valve and 2 filters to plan out fuel lines
• Thinking about interior paint so I can do some of that before assembly
• Planning for the finish kit, mostly what to remove

 Anyway the first GOTCHA was on this bracket, the plans show some holes that aren't there anymore.  They are labeled in the diagram "DO NOT COUNTERSINK".  It should actually read "DO NOT EXIST, IGNORE".  Yes that is what Vans told me to do.

Pretty soon you have some structure together and are assembling the seat frames.  Cutting the super-thick bracket for the control rod bearing was a bit of a chore, even with my overkill metal bandsaw.  But I got it done.

 

 Then you put the front floor ribs in.  These end up getting riveted on the bench by back-riveting.  Which is nice, because the rest of the floor rivets you need a friend to help with.  My buddy from work, Mark, and my dad helped with mine.  One luxury of getting old is you start to have more and more friends that are retired.

Then all of a sudden you have this beast.  This was right after I made the big move from the downstairs shop to the garage.  This winger has been nice and mild, so its been staying around 50 degrees in there which is sweet.  Will see what Jan/Feb brings.  Last year was brutal.

Had some awesome help countersinking.  Sure makes me happy to see this little guy help out.

Of course had a pretty large priming job this round.  Dad helped as usual.

I couldn't find a step where they tell you to countersink the upper part of the Fwd Bulkhead lower flange, but there is a note on a diagram to double flush 7 rivets under where the landing gear mounts go.  I had to get creative with countersinking tools to get that one.  But they turned out nice and flush.

There is a nutplate in the bottom skin that ends up between the two big fuse bulkheads.  I didn't catch it until it was too late.  But I have a super long and skinny flat rivet set that'll do the job fine.  If I did it again though I'd read ahead and install it.

The last steps are drilling some holes for the landing gear mounts.  These things are bears, and fitting your hands in between the bulkheads to mess with washers and nuts totally sucks.  Luckily a few years back I bought these super long double-jointed pliars and they were a life saver here.  Do yourself a favor and get some before tackling this job.  They saved me hours of pain.

When your done you have this!  Is pretty sweet, and I even got to show it to some folks when we hosted 2 Christmas parties.  Infamous Chapter 29, here I come!

Mid Fuse Ribs and Bottom Skin

This section was pretty cool.  The fuse starts getting its shape.  However, this must be the section where they really start slacking on the plans.  There are a number of gotchas in this one, and they can really screw you up later on so pay attention!

You start by creating some nice thick pieces that will be used to attach seat belts too.  Important stuff.  Then the big ribs start going on the spars and bulkheads you put together last chapter.

Here is the next bulkhead aft and the ribs you attach to it.

 

Then the thing gets big real fast and you need to stand it up on end.  I did make sure to measure this beast and make sure I can get it out to the garage.  The end is in sight for my time building downstairs in peace, quiet and warmth during the winter.

Here's the whole beast with the two bottom skins on.

**GOTCHA SECTION**
When putting on the skins I realized something.  For some of the outboard ribs it tells you to cleco them to the bottom skin and flute to match the curve.  For others it just says "flute the flanges...".  In these cases you need to make sure you put it against the bottom skin and flute to match, even though it doesn't say so.  Here I'm pointing to the ones I'm talking about, the F-1018-L/R outboard ribs.

On 26-3 Step 7, it says to dimple the screw holes in the inboard side of the intercostals that correspond to the flush nutplates.  There are 3 screw holes here, and each of them get a different type of nutplate.  The top one is a K1000-08.  This kind does not have the "divot" to accept a dimple.  I of course dimpled all 3 and the top one doesn't sit right.

What you need to do here is dimple the #40 holes for that top nutplate, but don't dimple that top screw hole.  The piece that goes over it is the F-1015C-L/R Mid Cabin Deck.  Its hole that corresponds to the top screw hole of the intercostal is machine countersunk.  There's also an inspection panel that slides in between those two pieces, so you don't want that countersunk or it'll be very hard to get in/out during annual.

Dimpled with the nutplate sitting wonky:

The piece that fits over this hole:

And the big gotcha's.  I'll just shamelessly copy from Mike J's blog because I can't say it better than him:

In summary, here's what I believe really should happen during Section 26-5, somewhere between steps 1-6:

• For the F-1015A-L/R ribs, dimple all of the #40 holes in the web of the piece, excluding the forward-most row that tucks behind the F-1004D bulkhead. Leave the #30 holes alone (careful, they crisscross!)
• Dimple the flanges of the F-1015B-L/R Intercostals to match the dimples you made in the previous step.
• When completing Step 6 on 26-5, the dimple callouts for the #40 holes in the F-1018-L/R are correct; however you should *also* dimple the three aft-most #30 holes that can be seen on the right side of the photo above. Are those holes not there yet? You'll want to fetch the fuse side skins and cleco this rib into place, and match-drill those #30 holes, then deburr and dimple the rib. Trust me, way easier to do now than when everything's all riveted together. As a final clarification on the #30 holes, none should be dimpled EXCEPT for these three. Refer to callouts on Page 29-15 Figure 1.

One thing I saw online but luckily did it correctly myself was putting the slightly bent forward flange of the F-1018 ribs inboard of the F-1005C vertical support channels.  Also applies to the F-1015A ribs whose forward flange goes on the inboard side. I saw cases were people accidentally riveted it in with that flange on the outboard side and it was a mess to clean up.  Remember you need to create a flat face which the side skins will mount to. 

Don't get scared when you see some extra parts that you primed laying there once riveting is complete.  At the beginning you cut apart the spacers to make F-1015E and F-1015F spacers.  You only use the "15E" ones in this chapter.  The "15F" ones go on the otherside of the intercostals but not until chapter 29 (Fuse Side Skins).

Yet ANOTHER gotcha.  This is the stuff that frustrates you.  On 26-6, step 9 has you dimple 2 holes on the Fuse BulkHead Assembly (F-1034A) that are shared with Rear Seat Rib Assemblies.  Problem is, those ribs have already been riveted on by step 6.  Total lazyness in planmaking.  To fix this, just do step 9 after step 5.  I'm just going to countersink them for a dimple.  They are unique from the others in that row because the rest get covered by a hinge:

So eventually you start dimpling and riveting this monster.  There are 978 holes in those bottom skins.  Woof!

  

The last two steps of this chapter are confusing too.  Which bottom holes in the bulkheads do you countersink, and which do you dimple?  The plans are clear on the big forward-most bulkhead (you couldn't dimple that monster after all).  But the rear two it never mentions anything about countersinking, but says to not dimple holes that correspond to rib tabs.  

After putting it together via plans you are forced into one solution - countersink the Rear Spar Bulkhead and Fuse Bulkhead holes that have a rib tab under them, and dimple everything else.

If I had to do it again, I could have dimpled everything (except the Aft Center Section Bulkhead).  You would just need to dimple all the rib bottoms and the Rear Spar/Fuse Bulkhead bottom holes before riveting them on.  Stated more simply, everything that gets riveted to the bottom skin gets dimpled unless its the Aft Center Section Bulkhead or touches the Aft Center Section Bulkhead.

When you dimple the bottom stiffeners, one end is squared off and one is cut back at an angle.  The angled side goes on the Aft Center Section Bulkhead, so don't dimple that hole.  Dimple the rest though.  Don't forget to dimple the upper flanges of these stiffeners too (#30 holes).  I forgot even though the plans were clear and had to buy a new squeezer to fix it.  DUMB.

Finally you finish.  Yeesh this chapter is kind of a doosey!

Flaps

Flaps are done!  It might be just me, but these seemed to take a long time for how simple their construction was. They are big (probably 8' each), so there was just a lot of time spent to get through all that deburring and drilling.  The day dad and I spent priming was a big one too, about a 9 hour job.

Now that the wings are mostly done, I'm sure glad I did both wings at the same time.  I couldn't imagine being at this point then having to go do it all over again.  There was definitely some economy of scale advantage to getting both knocked out at the same time.  I didn't always keep both wings in step-by-step lock though, only doing what made the most sense at the time.  For example during the leading edges, I only had enough room for 1 on the bench.  So I would get a long ways ahead on one and then catch up on the other just to save me from moving them around a lot.

The flaps were pretty easy.  No stainless pipe to deal with like the ailerons.  Lots of blind rivets.  For the trailing edge I used my trusty old door and angle iron.  Even though the flap overhung the iron by over a foot on each side, it still ended up arrow straight.

The first thing you do is create the big flap hinge brackets.  Its a little confusing as to how they go together L/R wise when you start on the Left wing, but in the end you figure out they are pretty much the same no matter what wing they are on.

The instructions have you put the bolt and associated hardware into the brackets to forcefully line them up before drilling.  I've read where others paid the price for not doing this, so I obliged.  Getting those washes in between the brackets can be a bear.  Luckily my mom gave me these left over surgical forecepts over 20 years ago.  I still have them because they are handy as heck.

Priming was a big job, because I scuff everything with scotchbrite first.  These little ribs just kill you, luckily Dad shared the pain with me.

I'm pretty sure these are the biggest rivets I've used so far.  AD470 4-10. They go through the middle flap brackets which are a big "sandwich" which consist of 6 pieces, the middle two being really fat.

My buddy John (RV-14 builder) borrowed me this trailing edge jig.  You put the extruded trailing edge piece in there and it makes it flat so you can countersink it with a drill press.  Here I'm holding it to the drill press table with a couple of clamped boards.  WHY did I not have this for the empenage?  What a no-brainer, this thing was awesome.  If your reading this and are still working on the tail, just buy it.

Here's the internal structure all riveted up.  I had to use the double offset set to get some of those rivets.  With that epoxy primer on this stuff, assemblies like this should not see the light of day for 100+ years.

Leading edge skins going on.

 

 Top skins

 

The plans have you back-rivet the two aft-most rivets in the top skin.  DONT DO THAT - its super easy to screw up.  The squeezer works perfect for this job, and its way easier.

The leading edge skins and the bottom skin is all blind-riveted.  These are the rivet tails from just 1 flap!