patmiller

[patmiller]

First off, I finally lined up a job, so the rapid pace of progress is going to slow back down shortly.  I’m going to work for a Silicon Valley autonomous car company, so we’ll be packing up and leaving Houston for sunny California.  I’m looking to live south of the Bay which will be more convenient to an airport (only 10 minutes!).  The new gig is across the street from Palo Alto airport so I can even fly to work if I choose.  I’ll have to load up the shop and truck it to California, but I’ve done this before.  I really hope this is the last time I have to move the plane by land.

But before I go, I want to get the big join done so that I can move the fuselage in one piece rather than a collection of smaller things (plus my hangar neighbor has offered to help me paint the cockpit interior if I get it done over Christmas!).  With the front side skins prepped and the attachments ready to go it was time to start riveting them on (Section 29-12).  I did some of the work flat on the ground, but most of it was done with the skins clamped to saw horses.  That made it easy to reach the various rivets.  I was able to back rivet most of them using my back rivet bucking bar.

  With that done, I was able to cleco the skins to the front half fuselage and make it look almost like a real airplane cockpit!

There are a bunch more parts to attach that have to go in after the skins are roughly in place.  So another day of part prep and priming is required to get there.   The center channel cover section has to be bent a small amount.  I did it by clamping pieces of wood across the channel and my bench and then carefully bending across the table edge.  I got a nice, straight bend with a gentle curve.  It fit well.

Then everything is clecoed to the skins and you get to riveting.  It took a few days to get everything done.  I was able to do the side attachments solo (a mix of back riveting and standard mushroom head/bucking bar for the tight squeezes), but the bottom rivets were just too hard to do well alone.  So my son dropped in for a couple afternoons to bang those out.  The cockpit became very rigid and strong as the rivets went in.  What used to look like a random collections of rivet holes quickly became a place where each bulkhead and stiffener needed to go.  As always, the holes lined up perfectly!  Thanks Vans!  There were still some holes left open.  In the next sections they get filled by the root fairings and the intercostals.  And of course, there are the lines of rivets for the “Big Join!”  I had to use a variety of techniques to get to the rivets.  I used my full array of bucking bars and even fabbed some small ones to get into a few of the tight squeezes.  I ended up using my offset rivet set a lot to get to the #4 rivets.  I do wish that I had an offset for #3 rivets as well.

With the structure in place, it was time to shore up the wings and to add the wing fairings.  There are a couple of stiffeners that get riveted to the spar webs.  Those were pretty easy to get on.  The stiffeners require a bit of work. These are dimpled before you cut them out which is different than the normal procedure.  It did help keep straight the sides that required dimpling from the ones that went undimpled onto the plane.  There are some big nutplates that required my big dimple dies.  There are sooooo many nutplates!  The fairing look nice once they’re in place.  I can now really visualize the wings attached to the plane.

The seat brace needs some work before it is added to the plane.  There are some guides that restrain the side-to-side motion of the seats and what looks like a clamp to hold the seat covers.  It took a while to dig out the parts because it wasn’t clear that the F-01405N seat back adjustment guides were cut from a bar of black plastic.  I went through the part bins three times before I finally dug it out.  I used a marking gauge to transfer the measurements and a chop saw to make the cuts square.  The guides get rounded off.  I just did that on a sander and then used a sharp knife to trim the threads off.

Next you fit a gusset that binds the seat back bar to the skins and intercostal.  This gets match drilled in place with a lot of #40 holes drilled up to their final #30 size.  The intercostal has some tough rivets.  I really wanted that #3 offset bar to get the ones that bind the intercostal to the side rib. The roll bar brackets are bolted on.  It’s a really tight reach, even for my slender fingers, but I got the nuts on the bolts and everything torqued up.

That completed section 29 except for the eyeball vents which I’m waiting to do until I get the instrument panel in place to avoid interference — the instructions say “Delay the following steps until after the completion of Section 35 to eliminate the possibility of interference with the bottom of the instrument panel.”  So, I’m just waiting to get the area at least clecoed in place before working on the vents.

With that, I’m just about ready to take on section 30 — the big join.  Well except for one thing.  Vans just issued a service bulletin warning of cracks in the tail cone that are developing in some of the fleet.  The cracks are not particularly dangerous, but it seemed like a better idea to get the fix in now instead of later.  In particular, I have better access to the tail cone when it is off the plane instead of needed to crawl through to the back after the join.  I pulled the tail cone out of the back corner of the hangar where it was literally collecting dust and laid it on its side for access.  I used moving blankets to pad it so that I could crawl inside.  I’ve seen others that do it by standing it on end, but that seemed a little extreme.  I had no issues doing it on the ground like this. So, I drilled out the appropriate rivets and clecoed the doublers in place.  There was no way to reach both sides here, so I had to wait until my son could get down to get them all done.  I drew a matrix on the outside skin so that we could coordinate better on the rivets. I was able to back rivet all but one from the inside.  The last one was just really tight.  I was finally able to get the head of one of my yokes on it well enough to drive it.  For a weird wart of a patch, it seems really strong and doesn’t look too bad.  And in any case, it’s on the bottom of the plane!

Before starting the big join, I wanted to make sure that I could really secure the fuselage parts to the saw horses.  I fabricated a spar cradle that slips into the spar from 2×6’s and a 2×4 stringer.  This way, I could screw the stringer right to the sawhorse.  It seems quite secure.  I also ran a stringer between the two sawhorses on the left so that they couldn’t accidently shift if I (or the enthusiastic dog in the next hangar) bumped into them.  I used tie down straps to help keep the back of the one half from shifting (hooked into the rear wing brackets).  The tail cone is a bit more precarious, but it still isn’t going anywhere with the longerons bracketing the front fuselage.  This piece is going to be pretty big — 15 feet or so.  It will barely fit in the back of the hangar.  I’m looking to get a larger T-hangar in California that will relieve some of these space woes.

When I look aft from the firewall, I now really get an idea of exactly how big this airplane is compared to my RV-12.  I think I’m going to have a lot of fun in this plane!

The next step is to get this monster clecoed together.  That is certainly a two-person job.  Once it is together, there are hundreds of rivets that are needed to complete the join.  That will be a chore!  I also have to finish fabricating a front block to let me use my rotisserie so that I can get the inside painted.  I’m supposed to be in California in 3 weeks, so I better get a move on it!

Finishing the forward fuselage First off, I finally lined up a job, so the rapid pace of progress is going to slow back down shortly. 

[patmiller]

With the first big join behind me, it was time to start building the actual cockpit.  I started by working on the control column.  The riveting was straightforward (I’m not yet sure why exactly one of the bearings gets a very small trim, but I’m sure that Van has a good reason for it).   It was indeed a lot of fiddling to get the washers onto the bolts that hold the column to the bearing.  I dropped washers many times.  In the end, I bought a set of feeler gauges to get the right thickness selected and then super glued the washers together into a single unit that I could then insert with a washer wrench.  That seemed to work fine and the column would drop with a satisfying thunk when I lifted it and dropped it.  However, as I tested over the next couple days, I found that, depending on the temperature, it would still sometimes bind.  I’ll make one more run at the washer sets before I rivet the side skins on.  There would still be access, but it is much easier to reach with the sides open.

Next up, I had to start working on the upper longerons.  The plans call for fabricating a couple of wood blocks that sit inside the longeron so that it can be clamped in a vice.  Unlike some of the Van’s models, the RV-14’s longerons come already bent.  However, you have to add a 10 degree twist.  Hence the wooden blocks so that you can securely clamp them.  I found it took a surprising amount of twisting to get a 10 degree twist to stay.  I went around almost 180 degrees!

  With the twist applied, you cleco and match drill in the engine mount brackets.  I was able to use the drill press to keep the holes nice and straight.  Most of the rivets are normal squeezed ones, but some are cherry pull rivets.  These seemed to go in well, but I found that the mandrel on several had broken early leaving bad rivet.  I’ve ordered some replacements and luckily can pop rivet them in place even after the skins go on.  The lower longerons (which are much shorter — I guess that they are shorterons) are built similarly.

  Then I have to fabricate some hinge pieces.  These hinges are used to connect the fiberglass cowling to the firewall.  You need to cut to a particular length and then remove some of the eyelets.  You only drill one pilot hole and then carefully match drill everything in place (with a shim) on each side.  I used cleco clamps to keep the hinge pieces in line while I was drilling.  I followed Van’s advice to add a cleco to every hole that I drilled.  The thing never moved.

That allowed me to pull the side skins out of storage and do a test fit.  The skin gets match drilled into the upper drag fitting and center plate.

  It took considerable work to get the blue plastic off on the chilly day I attempted it.  A light touch with the heat gun helped that a lot.  Then each skin gets marked for breaking the edges, radiusing the skin at the cockpit entry rail, and a dimple free zone near the wing.  I nearly forgot to feather the back corners, but caught that when I was checking the directions.  The skins each took a lot of work to prepare.  First I broke the skin edges, but deburring the edges was time consuming with long expanses and a wiggly skin.  There are a couple holes that need to be deburred as well.  The NACA vent opening needs special care.  You want to keep the exterior edge a sharp corner to make the vent as efficient as possible.  Once that is done, you have to dimple and dimple and dimple some more.  It was easier to do this with my C-Frame instead of the DRDT-2 because I could move the frame to the hole as needed instead of trying to move the skin around.  Also, the work tables were full of partially assembled cockpit and it would have been difficult to set up there.   With the dimples done, I then washed and prepped the surface with Comet and a red Scotchbrite pad.  I put the finished skin up on sawhorses to aid in rinsing it.  I used my heat gun to force dry the skin before priming the inside.

Since the skin is flush, I had to do about a bazillion countersinks in the four longerons to match.  Similarly, the center plate had to be countersunk for every dimpled hole.

x

The next order of business was to find all the accoutrements that get attached to the skins over the next set of pages.  It is nice that they are (mostly) all identified up front.  With the part count in the bins dwindling, it is getting much easier to find the parts quickly.   The plans detail how each one is dimpled, separated, and broken.  It is a lot of parts.

Hours later, I had all the parts appropriately prepared and scrubbed and ready for primer.

Pages 29-10 and 29-11 mostly detail part prep, but it does instruct you to rivet the angles to the intercostals.  These are 4-6 rivets and most can be easily squeezed.  The two closest to the angle are too tight for squeezing and have to be done with a rivet gun.  With the parts clamped to the bench, it was an easy shot.

A few things get back riveted to the skins in the next couple pages and then the skins go on.  There are some more parts to prep, but the bulk of the parts are primed, dimpled, and ready to go.

Building up the cockpit… With the first big join behind me, it was time to start building the actual cockpit.  I started by working on the control column. 

[patmiller]

With the firewall and floor mated, it was time to get to the first big join. The fuselage forward and the mid-fuselage need to get joined together so that the sides and longerons can be installed.  Both pieces are pretty big on their own, but joining them creates the first really huge piece of the build.  Right now, I can move any piece of the build solo, but after the join, that will not really be happening.

Before I slid the two pieces together, I had to finish attaching the cover plates (I had run out of time and had to stop even though I was so close).  This wasn’t very hard.  I could reach most of the rivets with my squeezer.  The ones really close to the tunnel had to be driven, but again they were easy reaches.  I almost mis-installed the cover plate by putting it on top of the cover ribs instead of beneath, but a careful look at the drawings convinced me to put it in the right place. This stiffened the front fuselage section considerably.

  I slid the two sections together so that I could outline the overlap section for priming (as called out for in the instructions).  It was a bummer to put it together and then immediately slide them apart.  I got the area masked off for a quick primer shoot.  Both sides were primed when the parts went back together. The piece nearly fills both of my tables!  I slid the tables apart so that I could get at the joint and cleco the parts together.

  It took a lot of clecos to get the pieces to mate.  Then there are some other pieces (drag fittings) that get bolted in to hold the spars apart or to secure the landing gear.  I had to dress up the gear braces because they had developed some rust spots.  After cleaning, I added a thin layer of grease to protect the steel. I also  finally got to open my pack of big 5/32″ clecos.

At that point, I was finished for the day.   I measured the spar distance because I needed some temporary 3/8″ bolts to secure the joined pieces on their side for riveting.  The next morning,  I had to fabricate a piece of wood that was 1 11/16″ wide to act as a temporary spar.  A standard 2×4 is too thin.  I ended up using my table saw to cut two separate pieces that I mated to match the distance.

  The drag fittings use some long, solid bolts.  These pass through both spars, the lower drag fittings, and the gear brace.  It was having a very hard time getting everything to line up so that the Boe-lubed bolts would slide through.  I finally gave up trying to do it by feel and  took a quick trip to Home Depot to buy some dowels.  I made 3/8″ and 1/4″ wooden tapered pins that helped immensely.  The narrow end would slide through the slightly misaligned parts and as I proceeded, the wider part of the dowel pin would naturally align the parts.  Then, I could either just tap the bolt through or use the bolt to back out the pin with everything in alignment.

My son arrived to help me get the assembly all tipped up on its side.  We picked the coldest day to do this!  The temps hovered at freezing all day.  We worked with the hangar door shut to keep the North wind at bay.

I don’t have any of pictures of the riveting, but it was generally straightforward.  Most of the inner ones require two people to reach.  I was on the bucking bar (mostly my tungsten bar, but a couple required the long anvil bar).  The ones for the stiffeners between the spars required me sliding my arm between to get a bar on the rivet.  Some people used their long special bar from the elevators, but I was uncertain where that one was.  My hand only got stuck once 🙂    We had to quit a bit before we were done with all of the rivets because the wife had come down with a friend and we were all going to dinner.  I picked up and finished solo the next day.  We had taken the fuselage off the support and laid it out horizontal, so I had to tip the piece on its side again solo.  It worked out because I could gently slide it to the ground to work on the remaining few dozen rivets.  I had a bit of a problem finding the big 5-5 cherry rivets, but Vans support got me straightened out as to the proper bag (I was incorrectly looking for 5-4 rivets — read the instructions!).  Others reported that these were hard to pull, but they went in with only reasonable effort for me.

With the rivets in place, it was time to final bolt and torque up the drag fittings and landing gear braces.  Again, the tapered pins made this a lot easier.

And voila!  We have finished the first big join!  You can see the tail cone sitting in the background.   In the not too distant future, I’ll be mating these two pieces together and creating the full fuselage!

The first Big Join! With the firewall and floor mated, it was time to get to the first big join. The fuselage forward and the mid-fuselage need to get joined together so that the sides and longerons can be installed. 

[patmiller]

I still don’t have a new job (though I am busy looking!), so I’ve been grinding away at the fuselage.  I finished section 26 which gave me a huge piece to work around.  I moved it off the benches and started working on the firewall.  The section is rife with reminders that stainless steel is sharp.  I suffered a lot of little cuts and just one big one.  It turned out to be a tough section to work on, taking me a couple more days than I thought it would.  Once that was done, I tackled section 28 which finishes the muffler tunnel and floor and joins it all to the firewall (with a lot of little bits tacked on).

  Section 27 – Firewall

You start by marking off the firewall pieces with parts that you will dimple/not-dimple and rivet/not-rivet.  I made a small mistake where I marked out some rivets for the battery box as “not dimple” that should have been dimpled.  This got carried over though the whole process of marking the support pieces and I didn’t catch it until the next section (not a hard fix, but a bit embarrassing).  Just a note to other builders to be careful here!  Once the two big firewall pieces are marked, you then transfer those to the support pieces and get to countersinking.  This process seemed to take forever.  There are hundreds of countersinks to make here.  It was just the first thing that I underestimated about this section!

With the countersinks done (and the parts deburred and primed).  It was time to attach them to the walls.  You can backrivet here, but it is trickier than it looks because of the depressions in the wall.  It keeps the backrivet panel from sitting flush.  The #4 rivets take a lot of hits to set, but I got a bunch of badly set ones because I was not careful with the backrivet bar.  Sigh.  Little did I know that these were just the first of many rivets that I would be drilling out.

The corners were a little easier to squeeze.  I had to be careful not to dent the stainless which is surprisingly easy to do.

The top part of the firewall bends backwards a little and is joined with a support bar.  Everything is joined with a fillet of tank sealant (oh, how I hoped that I wouldn’t have to open that smelly can anymore).  It made things pretty messy.  These rivets were set with either my backrivet bucking bar, my tungsten bar and mushroom set, or backriveting with the tungsten bar in tight quarters.  Many tough ones to set because of the large, flimsy structure.  I had to drill out a lot of bad rivets.  It got so bad at one point that I had to walk away for an hour.  I used the time to better organize my rivet collection.

  Just as I was finishing riveting the center section, I noticed that I had not inserted the joggled part behind the top section. This caused some gapping and I didn’t think that it would preserve the proper integrity of the firewall, so I had to drill out the entire triangle.  I got pretty good at it.  I started with a #40 drill which helped keep me from hitting the side of the hole and then used the #30 to get a hole to break the head off.  It all came back together nicely.

  The six firewall bolt holes have to be reamed to 3/8″.  I couldn’t figure out a good way to get them to my drill press, but in the end, I was able to bring my drill press down to the floor and get all the holes.

And finally, you have to add a bunch of nutplates and a doubler plate for the relay to the firewall.  A lot of people complain that Van’s is making all the location decisions for you, but I think it will help me a lot having these important things in “good” positions.  And it is much easier to place them now instead of when I have the engine mount and engine in place.  I primed these because they were dissimilar metals touching, but I then sprayed them with high temperature enamel (made for BBQ’s and grills).  Should be fine even in hot areas beneath the cowl.

Suddenly, I  had a firewall!

Section 28 – Fwd Fuse Lower Structure

With the firewall behind me, it was time to work on the floors.  This part of the build made it feel like a real airplane.  I was working on parts that would literally be exposed to me when sitting in my finished plane.  I pulled the floor sections back out and started dimpling (both #40 and #30 sized holes).  There are a few areas that don’t get dimpled.  The tricky one is the “drain hole” that I marked with an “x”.  The square area in the upper left is dimpled, it is where the comm antenna doublers go.  I was treating that a little differently (see below).

The comm antenna doubler plates have to have a good ground connection.  I didn’t want to have primer between the two aluminum sheets.  I decided to clean and backrivet these together before priming to maintain a good clean ground.

Then you start on the actual exhaust tunnel.  In retrospect, I think adding these clips after riveting the tunnel would have made it a lot easier to get clean rivets.

I got the tunnel and floors riveted together.  Some I could back rivet, but as the triangle shrinks, I had to get more creative.  The last couple had to be done with indirect riveting.  I have a large steel brick chisel that let me get some steel on top of the rivet and then hit it with the mushroom head on the backrivet bar.  Not the prettiest, but it will do.  Oh, and of course this is done with tank goop oozing out everywhere!

The tunnel section then gets joined with the firewall.  The sides are done with pull rivets because there isn’t any room to get to them.  The top section is done with driven rivets.  I tried to do them solo, but had a rough time of it, so I waited on my son to come down and help me.

The next part starts joining the tunnel with the shroud.  It is a clever design to provide a nice air gap between the hot tail pipe area and what becomes the center console area.  While I was manuevering things around, I stumbled and twisted a piece of the stainless across the base of my thumb.  It looks worse than it actually was, but it did fulfill the blood sacrifice requirements of the build.

  Next, various parts get added to the final structure.  Here is part of the cover structure that will contain the controls in front of the seats.

Then here the firewall gets firmly attached to the floor structure.  These plates are where the cowling will screw into fuselage.  This is literally the most forward part of the aluminum structure of the plane.  Everything else is “firewall forward” (engine mount, cowling, systems, etc…).

There are still many things to attach at this point.  I scavenged through the parts bin and found most of them (cover panel, battery box, hot air vent controls, a couple of firewall penetration parts).

I thought about back riveting the tunnel sides, but it seemed like it would be a tough reach in a few places.  I ended up tipping the whole structure and used my standard bucking bar and the mushroom head on the rivet gun.

Then I lay the structure flat again and added the forward bulkhead.  It gets screwed and riveted to the tunnel, and then the cover ribs get attached to the cover plate.  I got most of these with the squeezer, but where it got tight, I just used the rivet gun with a 3/32″ universal set.

To join with the floor, it seemed a lot easier to work from the side, so I tipped the floor section up again.  I was worried that the heavy bulkhead would tip, but with the cover ribs flanges riveted in and the 1/8″ clecos, it held just fine.  Pretty simple reach with the tungsten bar and the mushroom head set.

I don’t have many photos of the next day’s work,  but I started adding the bits and bobs to the back of the firewall.  I had to tank seal the penetrations in, fabricate the hinges for the vent doors, rivet the doors on, and then rivet on the battery box into place. There, the only hard part was countersinking the battery box.  It had to be done by hand because with the bends in place, there is no way to get my countersink drill set into play.  Here’s a picture of the “before” view.  I didn’t quite get the last piece in (the cover panel) because I ran out of time (I had to get home early to work on some honey-do items).  I also lost some time talking to a few recruiters about jobs.  ‘Cause I really do need a job.  Meanwhile, I’ll finish section 28 in about an hour and then start on the first big join!

A firewall and a floor… I still don't have a new job (though I am busy looking!), so I've been grinding away at the fuselage. 

[patmiller]

Well, I quit my job at the beginning of the month… I’m busy looking for the next thing — this just wasn’t the right place for me, so I decided to move on.  Meanwhile though, I’ve been relentlessly grinding away at the fuselage.  You can make a lot of progress when you work (nearly) every day!

It is almost certain at this point that I’ll be leaving Houston, so some of this work is designed to make it easier to load up the kit and roll it down the road to the next stop.  The wings are in good shape for this.  They are sitting in their nice low cradles with just the bottom skins, the pitot mount, and a few brackets to rivet into place.

I had been trying to finish out the wings, but lost momentum as I was working on the aileron controls.  I messed up one of the control rods and had to order a replacement.  That’s come from Van’s, but by then I was deep in fuselage mode and will return to the wings later.

Section 25 — FWD MID FUSE BULKHEADS.

So I dove into the first section.

This was mostly just bolting and riveting on various cover ribs, side angles, and miscellany onto the three main bulkhead bases.  The forward most one has the cover ribs, the second one holds the seat ribs and the final one holds the baggage ribs.

  The bulkhead bars are pretty hefty.  They are bolted onto the bulkhead.  To get the alignment right, you just slide a bolt through the final attach point which is sitting super accessible on the end of the wing! I love it when the parts I make look just like the plans!

I didn’t take a lot of pictures working on the bulkheads – the work was mostly monotonous. The silver nuts are temporary ones since the bars will come out and be slid in again later. The seat back brace is still in blue because it is just a temporary measure to help keep the side channels square.  Most of the rivets have to be driven — only a few can be squeezed.

Section 26 — MID FUSE LOWER STRUCTURE.

This section is huge!  I can’t imagine how many months it would take me to finish at the “most Saturdays” pace I was working at.  It has 22 pages and lots of parts and lots of riveting to do.

Section 25 — FWD MID FUSE BULKHEADS.

So I dove into the first section.

You start by adding some doublers to some of the baggage ribs.  These had a lot of “curl” to them, so I just choose to mount curl down.  The rivets hold them flat in any case.

  Next, you start preparing the baggage and seat ribs.  Lots and lots of deburring work.  I managed to stab myself with a file as I was working one of the doublers.  We have a saying around the house, “It’s not a project until you donate some blood to it!”

The ribs all get a collection of clips, doublers, and nutplates — oh the many, many nutplates I had to install.  Each rib is a little bit unique, so careful attention to the plans is warranted here.

Finally, you start building real structure again!  The seat ribs feature a mount for the crotch strap (for a 5-point harness).  It struck me that I was now building parts that I’ll use and see when the plane is done (rather than working on ribs buried in the fuel tanks).  Finally, you get to rivet the seat ribs to the bulkhead — starting to look real!

In the midst of this, you break out the big floor skin that really defines the mid-fuselage.  You have to flute the outboard seat ribs to follow the curve of the skin.  It wasn’t very hard to do… Just had to sneak up on the curve.  The holes lined up very nicely without having to mess around a lot.  You can see from the second frame that the curve is pretty big before the fluting!

The baggage ribs don’t have as many doo-dads to connect as the seat ribs. But they do have a lot of nutplates!  Also, you have to build out an idler bracket to attach to the bulkhead.  The only tricky part was bending an extra flange into each side.  I couldn’t get this to mount in either of my brakes, so I bent it by hand.  Just got it started in my vice and then finished with my flanging tool.  They came out pretty clean.

Then you add some more seat belt lugs.  The instructions have you rivet the top end together with an AN4-5 rivet, but I later had to pull these to get them to go through the holes in the bulkheads.

Then you have to start cutting into the big bottom skin and the two footwell forward skins.  It isn’t really clear, but the bottom skin is NOT symmetrical!  If you look closely, you can see that there is an extra set of holes on the right fuselage.  It’s in the pictures, but it’s never mentioned in the instructions.  Well, as luck would have it, I choose the correct side!  Probably not the end of the world if I hadn’t, but then I would have a comm antenna on the “wrong” side, I suppose.  The instructions suggested using a die grinder to remove the rectangles of aluminum (for the gear mains on the nose dragger version I’m building — not needed for a tail dragger).  That seemed like a crazy idea, so I used a drill and then rough sawed them to the correct dimension, then snuck up to the final line with a bastard file.  It didn’t take too long and the result was crisp and clean (but my arms were pretty tired afterwards!).  You also have to enlarge certain holes (different sets for tail and nose draggers).  I’m always vaguely terrified when I use my step drill.  I worry that I’ll click through one too many holes.  I mark the target ring with a sharpie so that I can see when to stop!

Then it’s time to dimple the bottom skin.  It’s really big!  I managed to do the whole thing (almost) on my DRDT-2 dimpler all by myself.  It is a mix of 1/8″ and 3/32″ holes that need to get dimpled.  And there are a few exceptions (I used orange tape to mark these).  This took a while.  If nothing else, it took me 10 minutes just to get the blue plastic off!

There was one dimple that I just couldn’t reach. It was about 1/4″ too far to get at from any angle.  Rather than pop rivet dimple it, I just put the female die into a holder and then used the C-Frame holder and a hammer to gently form the dimple.  It worked great!

You then build a mini-bulkhead in the front of the compartment.  This creates one the attach points for the main gear assembly (the seat ribs will straddle this).  That explains the hefty doublers that form the heart of it.  It is important here to get the little vertical seat attach angles straight up and down.  Later, you’ll slide the seat rib assembly right over it and you’ll be glad you got it right now.  I just clamped the brace to a square and it came out great.  The whole thing is riveted in place onto the bottom skin.  When you’re sure that it’s right, you squeeze the final rivets in place.  The second brace goes on after you get this onto the skin.  I just made careful measurements to verify that they were parallel.

Then things get big very fast!  You take the seat rib assembly and cleco it to the bottom skin.  I wasn’t careful about sliding the outboard ribs onto the correct side and didn’t notice until I had already done some riveting.  I managed to slide them past the braces so that the joggles were lined up correctly.  My son stopped by to help me rivet these.  We got almost all of them with my back rivet bucking bar.

With those done, you just pop-rivet the vertical braces onto the appropriate seat rivet and then add a power outlet bracket.

At this point, you go back to the baggage ribs.  They have detailed dimpling instructions.  Then you have to build out a structure to hold the steps (optional for the tail draggers, but it’s a big step for the nose dragger otherwise!).  Most of these are driven, but a few are cherry pop-rivets because the angle is too tight to get a squeezer or bar in to make the manufactured head.

As you build up  these sub-sections, you then attach them to the big assembly.  As I noted, I could not get the seatbelt lugs to pass through the holes with the end rivets, so I just drilled the out and re-squeezed them as I went.

I had to wait for bucking help to finish these off, but they came out looking great when I finally got to it!  After all those rivets, there were a couple little tasks to get to before closing out the section — A baggage floor stiffener is added and then the outboard baggage ribs are slid into place and riveted to the floor.  Whew!  21 pages done!

  Next up… the firewall!

A lot of fuselage time… Well, I quit my job at the beginning of the month... I'm busy looking for the next thing -- this just wasn't the right place for me, so I decided to move on. 

[patmiller]

Spent most of the long weekend working on a project for my brother… He wanted to make some replica B-17 nose art.  So I fabricated a 26″x26″ fuselage section.  It’s curved with two ribs and two stiffener and some AN470-4 rivets.  It came out pretty nice — it just took a bit longer to build than I hoped.

Then I got back to work on the aileron control rods.  I primed the main rods and started to assemble.  I was short some of the cherry max rivets, so I had to defer further work (and get an order out to Aircraft Spruce so I can have them by next weekend!).  One of the mandrels got stuck in my puller, so I had to break out my father-in-law’s trusty puller that worked like a champ.

So I started working on the gap seals.  The blue plastic was really clinging to the aluminum.  This does not bode well for when I pull all the old stuff off.  I had to strip off the adhesive with a large dose of acetone.  The worse news was that when I went to go dimple the seals, I found that my trusty Main Squeeze’ cam had broken.  It just doesn’t reliably go up and down.  So that meant that I had to bang out another order to Cleveland Tools since I don’t see a way to make much further progress without a good hand squeezer.  I did make some progress  by dusting off my pnuematic squeezer, but while it was fine for dimpling, I found that was having problems actually squeezing rivets (it may be because my air compressor seems to max out at 90 lbs pressure these days).  Sigh.  At least the new tools and replacement rivets should arrive before the weekend.

I had to do some work to actually fit the seals onto the wing.  The new aileron attach brackets are a bit larger and beefier, so I had to trim one end and make sure there is no interference (and no stress corners).

So, next week I’ll hopefully have the gap seals on and the aileron rods in place.  I made sure that I will have all the AN hardware (I ordered some extra from Aircraft Spruce to make sure).

Still dragging my way through the wings Spent most of the long weekend working on a project for my brother... He wanted to make some replica B-17 nose art. 

[patmiller]

I’m still working on the wings.  There are a lot of little steps that I skipped past when I did this kit out of order.  Now that I have the wings mostly in one piece, I’m catching up and getting to them.

The wings are in a wing stand now.  I built a new one because I wasn’t happy with the old one and didn’t want to use the “sling” style to hold the wing up.  I just assembled the wings flat on my tables.

When done, I tipped them into a lower stand made out of 3×4 plywood ends.  My son stopped by the hangar after his flying lesson and helped cut them out.  I just used a rib end and the leading edge tipped on its side to get the outlines.

Then I just added some 2×4’s to hold it all together with some castering wheels from the old stand and voila!

With the wings together and accessible, it was time to clear some of the backlog…  The wiring harnesses look deceptively simple to install.  They do pretty much just thread through the ribs in the grommets I installed oh so long ago, but you also have to correctly isolate and install a couple dozen wires into Molex connectors.  So, it involved lots of staring at the wiring diagrams and tugging wires to make sure I had the right white wire for pin 12!  Eventually, I got everything in the right place and did some initial zip tie work.

Another thing that was left hanging was addressing SB 16-03-28 which covered a potential for cracks in the spar at the aileron attach bracket.  This is one of those “inspect and fix if found” annoyances, but I wanted to be in front of it (in part because it is hard to inspect and a royal pain to fix if found.  With the bottom skins off, however, it is relatively easy to accomplish because I had access to both sides of the spar for drill out and for squeeing new rivets.

First up, I removed the old brackets and recovered the bearing (it gets reused in the new bracket).  The old bracket had a thick aluminum piece sandwiched between two thin bent pieces.  The new bracket has two thick pieces and super thick angle irons and a doubler plate and a secondary brace.  Even just clecoed in place, it is much stiffer with no discernible flexing.

Of course you have to go through the whole, cut out the pieces, file, deburr, etc… shenanigans.

It was a bit tougher to squeeze the rivets than I thought it would be.  The clearance was really tight.  For the first one, I built the full bracket and then tried to rivet to the spar.  This didn’t work well because the bracket rivets interfered with the spar rivets.  I smiley’d three rivets with the squeezer and the offset rivet set before I got wise and ground down the squeezer yoke.  This got me 7 of the 8 rivets.  I had just purchased a 5.5″ yoke that I was able to use to get the last one.

I still need to put the skirts on here and those will need a minor trim job to fit around the larger brackets.

Finally, I got to work on the aileron control rods!  It took a long time to dig out all the parts.  The wing kit parts had become a bit scattered over the last two years.  Plus I have already unpacked the fuselage kit which adds to the clutter.  I finally dug out all the rod ends and found the 1 1/8″ and 1/2″ tubes and the torque tube collar piece.

I cut the rods to length using a chop saw with a metal cutting blade.  The 1 1/8″ tube is thin walled aluminum and cut easily.  The 1/2″ powder coat tube, however is steel, so cutting it gave me a spectacular shower of sparks.  With the cuts made, it was time to pilot drill the 6 holes on each end.  I used a cheapo Harbor Freight V-block in my drill press.  It worked great.  It would  have been difficult to control without the block.  Once the pilot holes were done (and roughly deburred), I slid the rod end pieces in to match drill them the same way.

With that behind me, it was time to final drill to #30 and swap the silver clecos for brass ones.

The tubes and rod ends are raw aluminum alloy and need to be primed — inside and out.   Another builder I saw online was clever and taped off the end of the tube and poured in primer and then inverted the tube to let it drain out.  I did this, though I had a catastrophic containment failure when the tube end tore my glove and lacquer poured all over my hand.  I also primed the rod ends (after carefully labeling them so I could get them back into the right tube).

Next week is a long weekend, so I should have some time to finish out the aileron actuators.  I should also be able to get the gap fairings installed.  At that point, I really only have to finish the bottom skins for the wings.  I’m going to defer that until I really have to.  It’s nice having good access.  Plus, once I cleco the skins on, I’ll have them out of the way so I have enough room to start work on the fuselage.

Lots of little things to finish on the wings I'm still working on the wings.  There are a lot of little steps that I skipped past when I did this kit out of order. 

[patmiller]

It’s taken a while, but the wings are finally coming together.  With both tanks finally finished (there was a trivially easy to fix leak in the second tank in the corner where the tank attach bracket met the inboard rib… I just syringed some proseal into the gap and it closed up nicely), it was time to move on with getting the wings together.   I had a couple of projects on the leading edges that I had to finish.   While still in NY, I waited to finish the landing light covers because I didn’t want to finish them in the sub-zero temps.  Well, here in Houston, it was a balmy 94 degrees.  No more excuses.  The fit is OK, but I feel that I could have gotten a better seal.

  I was thinking about building over the 4th of July holiday, but instead spent a nice day down at the Lone Star Flight Museum.   They had the B-17 open for tours.

With the lenses in place, I fitted the stall warning switch.  I debated leaving this off since I’m planning to install a Dynon heated pitot with angle-of-attach sensing.  However, it is such a simple device that will help more than hurt, so I left it in.  I can always disable it or remove it if I find it burdensome.

With that, it was suddenly time to start assembling the wings.  The leading edges are permanently installed (rivets for the ribs, driven rivets for the skins).  I started with the LP 4-4 and LP 4-5 rivets that hold the inner ribs in place.  It is a tight squeeze, but it is so much easier to do this without any proseal clogging things up.  I used my father-in-law’s pop rivet gun here because it has a very narrow head which let me get in right next to the ribs.

Then I started to get the fuel tank in place.  Here, I only have a few bolts holding it in place, but it really looks like a wing now!

Next week, I’ll finish the left wing (bolts and screws for the tanks and the rivets that I can reach for the leading edges) and get started on the right.  I’m building a new wing cradle that can better hold the wings at this stage and prepare for riveting the bottom skins and applying the spar strengthening service bulletin.  I’ll leave the bottom skins off until closer to wing attach point.  It is much easier to initially fit the aileron controls, for instance, with the skins off.  Same with getting servos and pitot masts and and other things fitted.  It will move up the day to start on the fuselage as well!

Wings finally coming together It's taken a while, but the wings are finally coming together.  With both tanks finally finished (there was a trivially easy to fix leak in the second tank in the corner where the tank attach bracket met the inboard rib...

[patmiller]

After a long hiatus... tanks -- a lot!

After a long hiatus… tanks — a lot!

I’ve haven’t blogged anything in almost 9 months, but I’ve been very busy.  I spent a lot of time working on the my RV-12.  The condition inspection (more specifically, my updating the radio and adding ADS-B In/Out (a new GPS antenna and a new ADSB-In antenna) really kicked my butt.  It dragged on and on.

But through it all, I kept grinding away at the tanks.  It was really slow going.  Mostly I…

[patmiller]

Fuselage is here!

Not a lot to post, but my fuselage kit was just delivered… Of course I thought the wings would be almost done by now.

I was supposed to get a call from the trucking company to give me an hour heads up before the delivery, but the call never came. I headed out to the hangar at 3:30 because the kit was supposed to arrive by 5pm and traffic was building.

Finally, after 3 calls to dispatch, they got…

[patmiller]

My wife was out of town for the week, so I figured to get some extra shop time in.  I spent a couple of evenings finishing up the prep work for the tanks.  My hangar neighbor John was going to help me get started.  He was an F-16 crew chief and had some familiarity with the grey goo they call tank sealant.  It seemed better to have a go at this with someone who used this before.  The Rans Raven he’s building has a roto-moulded tank, so he had it a lot easier!

The tank skins were slightly deformed from sitting out so long.  The nose was decidedly more pointed than round, so I did a dry fit of the ribs to see if it would come back into shape.  That part worked out, but it was slow going just to get the ribs to line up.  I made a rib shaped spreader that helped some and I polished and pointed my bent up 3/32″ pin to make a drift pin.  With the ribs in place, the pointy-ness disappeared and I got a good fit.

I still had a little prep work to do on the end ribs.  I riveted on the nut plates (used to secure the fuel tank float).  They didn’t need any sealant because I’ll form a tank sealant gasket when I do the final install later.

Then I cleaned up the edges of the anti-rotation collars that hold one of the fuel fittings in place.  I decided that it would be a good idea to check to make sure that the nut fit into the collar correctly…. It very much did NOT!  I had to file and clean the edge quite a bit to get a good fit.  This would not have been very easy to do once the fitting was installed on the rib (would likely have had to drill it out and re-mount it!).

That gave me all the parts I needed to get started!  In anticipation of John’s arrival (he is SO not a morning person), I got everything prepped and laid out.  I pulled the sealant out of the fridge (keeping it frozen or cold prolongs the shelf life), set up the C-frame to rivet the tooling holes closed, and got my dixie cups and popsicle sticks ready….

At this point, I don’t have a lot of pictures because my gloved fingers were covered in sticky grey goo.  But I can tell you, it did not go well at all.  We started by trying to rivet in the VA-141 fuel flanges.  I tried a squeezer, but the rivet set caught on the edge and I couldn’t get a straight shot at the rivets.  I tried shooting the rivets instead, but I ended up clenching them AND distorting the flanges.  We tried drilling out the rivets, but we ended up messing up the holes.  We declared the whole adventure a total loss.  I’m ordering new parts from Van’s and we’ll try it again.

So, with that out of the way, we moved on to the really expensive parts!  There are 11 stiffeners to install on each skin.  You have to make sure that each rivet is well coated in goo before pushing through the holes.  We used clear packing tape to hold the rivets in place and back riveted the stiffeners in.  This was the first time John had seen back riveting.  I like it because I always get such nice, clean rivets.  The first 10 stiffeners went really well.

Now all this time it is really raining as a huge storm cell passed right over head (much better building day than a flying day).  I closed the big hangar door because the rain was pushing inside.  John went next door to close up his.

While he was over there, I set up the 11th stiffener, prepped the holes, taped the rivet line, slipped the stiffener in place…. Then I looked down.  There was water FLOWING though the hangar.  It was pouring through the bottom of the wall seam and running a half inch deep in places.  This was not a good day to have my electrical cords down on the ground!

Then the power went out!

The power came back on again a couple minutes later.  I was just prepping to rivet the last stiffener anyway (air powered!) with a headlamp.

So I spent the next hour pulling boxes and electrical off the floor and sweeping water out of the hangar.

Sigh!

I’ve ordered new end ribs and flanges.  They’ll come with the fuselage kit that will show up in early August (it also contains a new horizontal stabilizer skin — the old one had a big ding in it from an early back-rivet fail).

I won’t get a chance to get back to the shop this month since I’m taking a trip out west for my niece’s wedding.  It will be nice, some day soon, to do those trips in the RV-14!  But for now, it will have to be commercial.

When I do get back, I’ll rivet the stiffeners into the left tank, seal the rivet lines, and get ready to start putting ribs in place.  They’ll be tanks soon enough.

A not very auspicious start to the tanks… My wife was out of town for the week, so I figured to get some extra shop time in.  

[patmiller]

I finished up countersinking the fuel cap brackets and moved on to the tank attach brackets. These have a bearing, some shims, and three different kinds of nutplates that need to be attached.

As always, first I had to find everything.  I had put the shims by the brackets themselves when I was hunting up everything at the start of the chapter, but it took a while to dig out all the nutplates.  The MS21051-L08’s in particular were a bear to find.  They are in bag #3015.  They are the only nutplates in there.  The spreadsheet of parts was very helpful! I separated the shims on the bandsaw and carefully deburred the holes (the instructions note to do a good job with this, particularly on the #8 screw holes).

The shims have to be trimmed to match the ends of the attache bracket.  The narrow shim in particular has a very slim edge clearance to the outer nutplate hole.  I carefully sanded them down on my sanding disk to get the a close clearance.

I marked the “primer line” on the attach brackets and started clecoing the nutplates in as I found them.  I’m substituting K1100-08 for the K1100-08D because I’m going to use “oops” rivets instead of dimpling the tiny shims.  I’m afraid that the shims will warp badly in the dimpler.  The hole on the end, in particular, is way too close to the edge for my to think about dimpling.

I filed the cut marks off of the brackets before running them through the Scotch  Brite wheel.  The initial edge was a little sharp.  So I donated a few more drops of “Blood, toil, tears, and sweat” to the project.

The RV-12 was feeling a bit neglected.  The early low clouds had finally risen.  My son Ryan came down for the afternoon, so we fired up 3EN and did some pattern work.  He is getting ready to start his flying lessons, so I let him do one of the takeoffs and one of the landings.  He did a great job!

I primed up the external parts of the brackets and shims and countersunk the brackets.  The picture shows a test fit.  The bracket lays tight to the skin and the shims have sufficient clearance.

The final step for the day was to rivet the flange bearings onto the brackets.  This is where I really like working both right and left together.  I’m able to make sure I’ve got everything set up correctly.  The nice mirror image gives me some assurance that dyslexia didn’t bite me here.  I don’t show the riveting, but it came out pretty nice.

I have a few more things to finish up before diving into the Proseal.  I have to rivet some nutplates to the shims and then the shims (with more nutplates) to the brackets. I’m using the NAS 1097 rivet trick here rather than dimpling to avoid warping the shims.  I got the light countersinks done, but then had to jet to meet my wife for BBQ at Killen’s.

Tank attach brackets I finished up countersinking the fuel cap brackets and moved on to the tank attach brackets. These have a bearing, some shims, and three different kinds of nutplates that need to be attached.

[patmiller]

When I left off last week, I had dimpled the #8 screw holes and hadn’t yet started in on the 3/32″ skin holes.  There are a lot of them!  Because of the way the tank skin is bent, I needed to do some work getting my DRDT-2 set up.  In New York, I had a nice bench with an overhang set up permanently against the garage wall.  For most work here in Texas, I can get away with bolting my dimpler to one of the EAA work tables.  For the leading edge and tank skins, I need a bit of an overhang.  I thought of a bunch of possible ways to set this up.  In the end, I did something very simple and effective.  I used some 3.5″ x 5/16″ lag screws and a piece of 2×6.  This very solidly tied the extension into the table.  A couple of 1″ lag screws holds the dimpler to the 2×6.  It worked very well.

So I sat in the comfy chair and twirled a dull drill bit in the holes.  I like this method. It is very fast and easy to control.  It just barely takes off the burr while leaving the hole nice and smooth.

I had high hopes of getting in some practice touch and goes, but all thoughts of that were quickly dashed.  It really poured! Even when the airport was in the clear, there were nasty thunderstorms lurking all around all day long.

The DRDT-2 and the carpet covered boxes worked vey nicely.  The dimpling went quickly, but there were still SOOOO many of them!  I finally got all of them done…

Next, I worked on the fuel caps.  There’s a pretty red anodized base and a cheap looking plastic sealing cap. I can get replacement ones made out of machined aluminum, but at $145, it is pretty pricy.  I don’t like the idea of painting the plastic though.  Will likely defer until it is time to paint the plane.  There are some steps, that I’m really excited to get to.   One of them is this shot of the fuel cap base clecoed in.  Pro-seal time is close at hand!

One clever hint I saw is to set up a swiveling base for the stands.  The Pro-seal is messy and hard to work with on a good day.  These swivels will let me rotate the tank so that I have a good (better?) angle for both applying the sealant and for riveting.  Not quite done in this picture.  I cut these pieces from the end of the 2×6 I used to support the DRDT-2.  Added a rounded edge and then drilled them out for a 5/16″ hex bolt for the axle. We’ll see how they work soon enough.

Next time, I have a few non-Pro-seal tasks to finish on the tank attach brackets and shims. Standard trim, deburr, prime (just the external parts), and rivet.  If I get really saucy, I’ll do the nut plates on the inboard rib (screws pull in the fuel lever sender.  No gasket, only more tank sealant).  If I’m super productive, I’ll do the first set of sealant tasks (closing the tooling holes and adding the fuel flanges and anti-rotation plate).

A day of dimpling When I left off last week, I had dimpled the #8 screw holes and hadn't yet started in on the 3/32" skin holes.  

[patmiller]

I’m finally back from my month long hiatus.  Some things went as planned, but I didn’t get as much flying in as I hoped.  I had hoped to fly to Fredericksburg for Memorial Day weekend, but the strong area wide thunderstorms put a crimp in those plans.  Somehow in a battle between an 865 pound plane and a Texas thunderstorm, I know who will win!

I did make it up to Denton, TX for my LSA-Inspector course.  I learned a lot.  Much of the course was about how to correctly fill out paperwork to keep the FAA happy, but there was a bit of hands on work.  There was a 60 question test at the end of second day.  I aced it, of course, as it was just a bit of memorization.  This didn’t actually get me my certificate.  I had to go down to the Houston FSDO (Flight Service District Office) to get someone to look at my paperwork in person and get me a temporary certificate.  I’ll get a new Wilbur and Orville FAA card in the mail in a couple of weeks.  I don’t actually need it to work on the plane, but will need it in October when I sign off the condition inspection for N903EN.

My sister-in-law keeps digging up some of my father-in-law’s old tools (he built a BD-4 and most of a BD-5).  This time, she found a rivet puller and some Avex rivets.

The last time I took the -12 out, I got a message on the EFIS warning me that the backup battery needed to be tested (It has an internal timer that makes sure the battery is tested once a year).  The test is really simple, actually.  When you shut the EFIS down there’s a button to run a battery test.  The way it tests that the battery will stay up for 45 minutes is to simply keep the display on for 45 minutes and see if there is still battery power remaining.  It passed with flying colors.  I’m good for another year.

  I left off last time after getting some of the countersinks done for the tank baffle on the left tank.  I finished off the other 150 countersinks and then started working down the instructions.  Next up was prepping the #8 screw dimples and putting a slight bend in the trailing edges so they hold down better.  I really like these Avery pliers to do that.

Then I finished up the J-stiffeners.  Just had to unclamp them, deburr, and dimple.

The instructions suggest using a C-frame to do these #8 dimples as they will come out “crisper” than if you squeeze them.  I used the C-frame on the trailing edges, but ended up squeezing the side ones.

I still have to dimple the interior 3/32″ holes for the ribs, but I need to build an extension for my DRDT-2 for that.

So, I’ll need to make a quick stop at Lowe’s aviation department and get a little lumber so that I can run the dimpler off the edge of one of my EAA tables.  Once that’s done, there are a couple of outside pieces to finish up (countersinking the fuel cap, installing some shims, etc…) and then it’s on to the sealant!  Luckily, my hangar neighbor John used the stuff as an Air Force crew chief, so I’ll have some of his expertise to lean on.

I can hardly wait to get the tanks sealed up since things will happen fast after that.  I will finish up the leading edges (just have to put the landing light lens in) and start installing stuff on the wings.  My fuselage is ordered and should be here in early August!

  Lots of work, but somehow the tanks look the same! I'm finally back from my month long hiatus.  Some things went as planned, but I didn't get as much flying in as I hoped.  

[patmiller]

With my wife out of town for ten days, it was time to put some serious time in at the shop!  The tanks have many, many stiffeners that need to be finished off.  I rough shaped the pieces with a file and sander and finished on the ScotchBrite wheel.

Then all the holes have to be dimpled!  Careful to get them the right way!

Next up are the Z brackets that hold the tank to the spar. A lot of the part prep work is done before separating the pieces.  You ream to final size and make all the countersinks right on the whole bar.

Then it was time to cut the pieces apart.  The stock is pretty heavy, so I used the bandsaw.  Then I used a bastard file to trim the roughest part of the edge before finishing the piece on the belt sander (bulk) and ScotchBrite wheel (final).

  My buddy Carver showed up to help.  He had been thinking about building an RV-12 or -14 as well (which is how he ended up wandering into my shop in the first place), but now he’s thinking about a Zenith Sport Cruiser.  That’s a nice plane too!  Not super zippy, but it is much easier to build and can haul a lot of stuff into some shorter strips.

I set him up working on the J stiffeners.  You drill one carefully measured hole at the end and then work your way across the tank.  He is not a “tool” guy, so I showed him how to use a marking gauge to measure from the end and a punch to start the hole.  Then we got the stiffener lined up and drilled the other holes.

I worked on prepping the Z-brackets.  The orange tape masked out the connecting surface with the tank (as it will get proseal).

Carver had a bunch of “honey-do’s” to get to so he headed out while I kept plugging away at the Z-brackets.  All but two of them get 3 nutplates each.  So I started working through the pile until I had them all riveted. up.

Then we get to work on the tank skin.  Most of the skin parts are delivered ready to edge finish.  The tank skins still had some considerable tabs left.  I took them flat with the bastard file and then finished dressing the edge with sandpaper and ScotchBrite.

At this point, the tank baffle is inserted and cleco’d in place.  We need to counter sink all the holes.  Every 10th hole is left in its pristine state.  When we finally proseal this in place, the un-countersunk holes serve as a strong anchor to align the baffle.  We wait for the sealant to set up and then do a quick countersink on those holes.  I checked each hole with a rivet to make sure it was just barely flush.  I’ve got the countersink totally dialed in now (good as I have another 100 holes to go!).

So here’s one tank.  J-stiffener in place.  Baffle countersunk (one side).

I’ll be taking a month long break from building at this point.  The next three weekends are full up.  My wife is back from her trip and it’s her birthday.  That means a straight zero chance of getting out to the airport.  Then we’re taking a trip out to Fredericksburg for Memorial Day Weekend (cool 1942 USO Swing Dance).  Then, I’m finally taking the course so I can get my Light Sport Repairman Inspector rating (to sign off on inspections for the RV-12). When I finally have a chance to get back to the shop, I’ll pick back up on the countersinking.  At that point, it will start to get real!  I’ll be mixing proseal and gluing up parts!

Stiffeners and Tank Brackets With my wife out of town for ten days, it was time to put some serious time in at the shop!  

[patmiller]

One of the more time consuming building tasks is parts preparation.  The fuel tanks are no exception.  There are 8 ribs, many short stiffeners, a long J-stiffener, and other small parts to prepare.

This last week, my wife was out traveling, so I had more time to play in the shop after work and on the weekend.  My first task was prepping the ribs.  I spent a little time digging out all the parts and sorting out the ribs. The flanges need to be right at 90 degrees and they must also be fluted to lay flat.  I used my carpenters square to check the bends (mostly pretty close!).

Then you need to position and drill a fitting to the inboard rib.  There is an almost identical one on the bottom edge.  I presume that this is to help qualify the kit under the major portion rule.  In any case, it isn’t too hard.  I have a nice marking gauge that makes it easy to scribe sharpie lines.  The next instruction says to use a step drill to make a .75″ hole.  I dug around in my tool chest and the parts boxes, but I could not find my step drill anywhere!   So that was all for the night until I could visit the local Lowe’s aviation department.

Friday evening, I stopped by my son’s shooting range after work.  We ran a couple of boxes of 9mm through his pistol and a nice CZ 75.  The range also had a new fully automatic machine gun that we ran.  After all that fun, we headed down to the shop (with a stop to get the step drill) to get a little work done before a late dinner.   My hangar neighbor, John, was there, so we chatted with him for a bit.  He just got the wings mounted on his RANS S-20 Raven.  Then Ryan drilled pilot holes in the left and right ribs.

I step drilled the full sized hole in both (drill press).  Then I clamped the fitting to the rib, match drilled a couple of holes with clecos before Ryan finished match drilling the other holes.

Saturday was beautiful.  I got to the shop very early in the day and went flying.  I ended up flying to KGLS Galveston.  It wasn’t a long trip (52 nm), but it was my first trip to a towered airport since last June.  It was also the first time that I landed my RV-12 at any other airport.  So quite a momentous flight!  I used the Dynon navigator (though it is hard to miss Galveston… if you hit the Gulf of Mexico, you’ve gone too far!).  I came in from the NorthWest, but had to cut over to land 18. A nice climbing left turn back to the NorthWest got me headed back to KLVJ. The funny figure-8 at the end happened as I was coming into Pearland.  It looked like there was traffic getting ready to depart Runway 32 (the winds were light, but favored 14).  Since no-one was talking, I decided to circle back and give myself more space.

I fueled up and watched the local banner tow plane take off, make a low and slow tight turn back and the pick up the banner.

With the flying out of the way, it was time to settle back into building.  I really wanted to finish getting through the ribs (for both left and right tanks).  I worked production line fashion.  I started by twirling a drill bit in the 3/32″ and 1/8″ holes to knock down the big burrs.  Then I shifted to a fine file to knock down the rather substantial burrs that rimmed the lightening holes and tubing holes (maybe 1/32″ high — it took aggressive filing to get it small).  Then I used a small ScotchBrite wheel and sandpaper wrapped around a bit to get at the holes.  I also hit the flanges with a ScotchBrite pad. A quick file to get the tool marks off the flanges, and on to the next rib.

Once that was done, I moved over to the grinder with the big ScotchBrite wheel to polish the flanges and to bevel the gaps on the front of the ribs.

  The next step is to dimple everything.  I needed to do 100’s of dimples.  I’m using the tank dies to get a slightly larger dimple (the idea is to leave a bit of room for the tank compound).  The dimples have to be very crisp to prevent leakage.   I set up my geezer squeezer on the side of my table so that I could easily strong arm all the dimples.  I felt like Popeye when I was done (right arm only).

Finally got both piles dimpled.

Next, I had to dimple for some K1000-08D nutplates.  These are used to mount the fuel level sensor.  The screws will tighten and “smush” the tank compound used as a gasket.  These don’t need any sealant, but they do need to be dimpled so that the gasket lays flat.  I might have considered using the “oops” rivet trick, but the plans call for (and the kit provides) the -08D nutplates, so dimpling seemed fine.  This is not in a critical leak area.  I dimpled these (normal 3/32″ dies) using my DRDT-2 dimpler (now fastened with removable bolts into the work table).

The final step for that evening was to drill some 7/16″ holes in some tubing clips.  That is a bit of a weird bit size.  But, I had earlier gone through the plans to find as many of these “special” sizes as possible.  Sure enough, I went to my drill bit draw and there was a brand new 7/16″ bit.  The drill press did a fine job of finalizing these holes.  I used the sandpaper wrapped around a drill bit trick to smooth these holes.

My wife is still out traveling and my son was off work Sunday, so we decided to take a trip down to Gulf Coast Regional Airport.  This was a substantially longer trip than any other I’ve take in the RV-12.  The winds were not too bad at KLVJ (10@160) so the departure on 14 was uneventful.  The trip was very bumpy with a lot of turbulent air. It was clear that the crosswind component was growing, however.  As we got to KLBX, we noted that (1) Runway 17 is right traffic and that the winds were not as forecast.  We had to really crab into the wind.  The airport was also very busy (it has very cheap fuel) with some GA traffic, a Dow Chemical jet, and some folks shooting practice ILS on 17.  My landing was pretty nice, considering the heavy and gusty crosswind.  The restaurant there is very nice.  Reasonable prices, friendly waitstaff, and very good food.  The tie down area does lack for chocks though!  I managed to use the tow bar as an impromptu chock and borrowed another tow bar from a Cessna driver who had just landed (he was fine using his parking brake).   We did eventually scrounge up two pairs of chocks (the RV-12 needs two pairs because it will move on its castering nosewheel with only one pair).

So, the first order of business on getting back to the shop was to make two sets of lightweight chocks to carry along.  I had some scrap 2×3 that I ran through the table saw and the chop saw and made these:

There was a bit of time to do some work on the 14, so I plunged ahead and got the vent line clips and 00005A stiffeners cut and deburred.

Then I started marking and cutting the 00004 stiffeners.  There is a lot to cut out (20 all told).  At this point, it was starting to get late, so I left the filing and deburring work until next time.

Next up:  I’ll finish the tank stiffeners, cut and deburr the tank attach zee’s, rivet on the required nutplates, and match drill the J-stiffener.

Tank part prep One of the more time consuming building tasks is parts preparation.  The fuel tanks are no exception.  

[patmiller]

I planned to get a nice early start out at the shop this weekend.  The weather forecast called for stormy, windy weather for Saturday.  However, when I got to the airport, it was calm and clear.  So, I hopped in the RV-12 and took a couple quick turns around the airport.

Then I settled in and started the final work on the aileron.  I had to finish riveting the nose ribs in.  The top of the nose is tightly curved.  I was able to squeeze a couple of rivets, but I had to drive some.  The bottom two rivets on each rib are pulled because the curve is way too tight to even get a bucking bar in.  Then you have to jockey the top skin into place between the spar and the nose skin.  The instructions have you clamp a piece of wood to the skin to help keep it straight.  Here, I just drilled some #40 holes and used clecos to hold the wood in place.

The top skin is easy to rivet since you have good access to the back of the rivets.  I just started in the middle and alternated sides until it was all done.

Then the end ribs get riveted to the spar.  On one side there’s a double, so you use 4-6 rivets.  The other side uses 4-4’s.  It is too tight to squeeze.  I ended up using an offset rivet set that just barely fit in the gap.  I got everything in nice and tight with no gaps and no smiles.

Then my buddy Carver showed up to help.  His timing was good because the bottom skin takes more time to rivet than the top (because you have to slip your arm inside to set the bucking bar each time).  Carver was on the rivet gun with the big mushroom head. I kept my arm inside with the bucking bar and inserted each rivet as Carver pulled the clecos.  It went really fast.  I made sure to remove my bucking bar before we closed up!

Carver had to leave to attend to some “honey-do” items, so I closed up the main ribs with some flush pull rivets.

Finally, it was time to pop-rivet the counterweight in place.  The rivets then get lightly rounded off with a small hammer.

Finally, we set the wedge for the trailing edge.  These use the double-flush technique.  I lightly squeezed each rivet to set the flush head on top, then flipped it over to set the bottom shop head.  The heads filled the dimple quite nicely.

That gave me a nice trophy to hang on the wall!

I clean everything up and put my tools back in the shop cart (I like that everything has a place again).  I pulled out the first parts for the tanks.  I’ll build them side-by-side on the two benches so that I can keep the mirrored parts straight.  This way, I’ll be ready to dive back in in a couple weeks (missing next weekend because I’m on a two-day bicycle ride with my brother).  But, my wife is heading off on a ten-day trip, so I’ll be able to log a lot more time in the shop for a while!  That’s good because I’m going to pull the weak intercom out of the -12 and replace it with one integrated into a (new) radio.  I’ll also install the ADS-B out WAAS GPS and take care of a small service bulletin.

Aileron is finally done (again!) I planned to get a nice early start out at the shop this weekend.  The weather forecast called for stormy, windy weather for Saturday.