Wednesday, May 28, 2014

23-05 spar cutouts


Not a terribly difficult page.  The spars pass through the side skins, so there must be a hole for them to do so.  The factory cuts the same hole on both sides, but leaves it too small for either.  The spars aren’t quite symmetrical either, since the spars pass in front / behind each other.  All I had to do was (double & triple check before starting) cutting the appropriate openings.

IMG 3260

Left Skin w/ Spar Cut-out


IMG 3261

Right Skin with Spar Cutout

Tuesday, May 27, 2014

23-04 side wall supports

OK, I’m going back to “book order” of assembly.  I’d like to do the wiring, but most of the wiring originates on the upper firewall / instrument panel and that can’t be installed until there’s a skin in place.  Plus, I’m wary of missing something that is a skin dependent installation and making it difficult to something else.  As far as access is concerned, the most popular solution via VAF is to put the fuselage on its side in some sort of cradle.  I’ve already built two cradles for the tailcone & wings, so it shouldn’t be too hard to make a 3rd one.

With that decision, I’m back onto chapter 23.

IMG 3252

Right Side Supports


IMG 3254

Left Side Supports 

Friday, May 23, 2014

27-05 Brake Lines

The hard part of doing the brake lines is putting on the damn fittings.  Sometimes the tubing is too tight to allow the compression fitting to slide over the part of the tube with the ferrel.  I’ve used creative cussing, some judicious shavings and novel applications of cleco pliers to squeeze the last few mm of hose into the nut.  Whew!  Anyway, back to business...


IMG 3239

Aft terminations of main brake lines

This is a pretty cool shot—you’re looking at the L brake line as it exits the mid bulkhead and is terminated by the nut for a 45° elbow.  I put tape over the end to keep debris out.

IMG 3240

Brake Line Installation

27-03 #8,9 Rudder pedal installation

This pretty much sums it up.  Installing the pedals onto the firewall shelf while they were on the table was easy.  I’m sure I could have installed the pedals in to the cockpit with the shelf in place (and the skins are supposed to be on, too) but it would have been a bit more difficult.


IMG 3237

Rudder Pedal Assembly

28-06 #11B return fuel line to firewall

Recall that I had installed the fuel system earlier.  This step was omitted because the firewall shelf wasn’t secure, so I didn’t attach the fuel return line to its fitting.  That’s now been accomplished.

IMG 3235

Return Fuel Line Fitting

This is a view from the bottom of the fuselage looking up at the bottom of the fire wall.  The masking tape was just a quick way to prevent the sleeve & nut from falling all the way down the fuel return line.

23-03 #4 Proseal seam on firewall

Using the same stir stick, I applied a thin layer of Proseal to the top edge of the lower firewall section and mated the firewall shelf and lower section.  (The shelf was a bit heavier, since I had also installed the rudder pedal assembly.) I clecoed every other hole to get good pressure on the sealant.  Predictably, the LP4-3 rivets didn’t go in smoothly or evenly so I had to use the #30 reamer first.  That got sealant all over the reamer, but I was able to clean it off with rubbing alcohol before it cured.  I also cleaned all of the gunk off of the clecos and salvaged them from being glued shut.


IMG 3232

Proseal between shelf and lower firewall 

 This shows a close up of the bead of Proseal.  This section is representative of the bead along the entire length of the seam.  I’m actually kind of proud of the way it turned out.

IMG 3233

Firewall and Shelf assembly 

Just a view showing the firewall shelf in its final position. 

21-17 #9, Proseal to boarding step

I received the small bottle of Proseal from Van’s last week, and finally had a good day to put it to use.  I accomplished several steps that had backlogged while waiting for this stuff, so this is the first of 4 or 5 posts in a row.


IMG 3230

Proseal on boarding steps


I placed a bit of cardboard in the openings seen on the inside of the steps (from Raison Bran, if I recall correctly) in order to have a surface to smear stuff on.  I just used the wooden stir stick that came with the Proseal and gooped it and smoothed it out as best I could. 

Wednesday, May 21, 2014

EAA Tech Counselor visit #2

Bob L came over to the shop again today to do another check up on my progress.  He’s out of the forms from the EAA, so I’ll amend that to this post sometime later when he gets it to me.
Overall, he seemed to think I was doing well and had no major concerns.  He did point out some flush rivets that were a bit proud and could be re-squeezed and expressed some concern about the flares for the fuel lines.  He opined that I’ll probably have some leaks, but it was based 50 % on some minor imperfections on my very first flared tube and 50 % on the fact that everyone has fuel leaks.  I debated pulling out the fuel system and re-installing all new tubes and fittings, but I reason that there’s a good possibility that at least one of my lines won’t leak and will be usable as currently installed.  Yes, removing & re-installing the lines after everything is built will be a royal PIA, but if I yank & replace everything now, I’m pretty sure I won’t learn anything since there’s no information to be gained by removing untested lines.


Update, 5/31/14
Bob sent me the text of his comments to EAA.  Apparently they EAA have a new on-line submission form, but it doesn’t have a good mechanism for giving feedback to the builder.

Test from the comment box:
This my second visit of David's RV-12 project.  David is making good progress.  I found no major issues with the build.
We did discuss ensuring that all flush rivets are truly flush, as well as checking the tube flares for cracking and/or burrs.   I shared with David the type of tube sealant I used.
Overall, David's RV-12 project is progressing well and built per the plans.

27-04 brake cross over lines

IMG 3226

Brake Crossover Lines

27-03 Well, you can’t see the drilled brake torque tubes, but you can see that there are some nice AN4 bolts holding rudder pedal pads onto the rudders, so you can presume that the holes are present.  The drilling wasn’t too difficult, just tedious.  As shown in the previous post, I used a pair of vice grips to hold the rudder pedal and the brake torque tube together.  It was pretty straightforward to drill #30, place a cleco and then do the other side.  I left the cleco on the first side and did the #30, then #19 and finally the 1/4” drill holes.  I put an AN4 into the result hole to maintain alignment then did the #19 and 1/4” on the first side.  This hole (sorry, can’t resist the pun) process was repeated for the other 3 stations.

27-04 The brake cylinders were cotter pinned in place and the brake lines were fabricated and installed.  The error of the day was to not pay attention and I transposed the locations of the 45° and 90° elbows.  This was corrected before I went any further.

27-03 drilling brake torque tubes

Oops.  I got too involved that afternoon and forgot to take a snapshot of the holes drilled in the rudder / brake assemblies.  Sorry, you’ll have to just look at the next post.

27-02 initial fitting of brake cylinders

This guy was a real challenge because of too much powder coat that got inside the tube that accepts the torque tube for the pilot’s Left brake.  I ended up getting a stainless steel rotary brush from my Dremel kit and putting it on the drill and buff the inside of the tube to get out some of the powder coat.  After that, it was a tight fit, but I got the greased torque tube installed.  I checked the friction of rotation of the pilot’s L brake against the other 3 and it feels pretty much the same to my hand, so I expect that there’ll be no significant difference to the feel to my toes when I actually go to use the brakes.


IMG 3219


Initial Assembly of Rudder / Brake Cylinders

This picture shows the pilot’s brake pedals.  The red cloth is to protect the finish from being scratched by the vice grip that is holding the brake pedal in alignment with the rudder pedal, prior to drilling the pilot holes up to final size (1/4”).  The brake cylinders are only pinned in place, without the cotter pins that went on later.

28-06 fuel return line

Although easier to work with, the fuel return line was fairly difficult due to the long run and tight spaces within which to work. 

IMG 3209

Fuel Return Line from Firewall Shelf

Starting at the forward end of the fuselage, we are looking at the vertical tube in the center of the picture which is the fuel return line.  The upper fixture is finger tight without any thread sealant, since the firewall shelf is only clecoed in place at this time.  There are a few waves in the line, but it’s functionally straight.  It’s clamped on the firewall and then heads aft.

IMG 3210

Fuel Return Line and main Fuel Line in tunnel

The return line is clearly smaller than the fuel feed line and they parallel each other as they go through the tunnel between the seats.  This photo is oriented up=forward, down=aft. 

IMG 3211

Bulkhead termination of fuel return line

This view is from under the belly, looking up through an access hole.  Although not convenient, the access did exactly what it was supposed to and I got things attached.  I did my second new guy mistake and started flaring the tube before I put on the sleeve & nut.  I had to cut off ~ 1/4” and flare it again.  I think I’ve got this burned into my experience bank by now.

IMG 3216

Fuel Return Line from aft bulkhead

Here’s the other side of that bulkhead fitting.  This run is a big “U” shape with an upturn on the far end of the “U”.  


IMG 3217

Fuel Lines padded together

This is looking sideways through the fuselage.  You can see the two lines are padded and clamped together to keep them from rubbing and fraying against each other.  There are 3 sets of these cushions.

Sunday, May 18, 2014

28-05 fuel line, cut off valve to gascolator

Lots of tube bending and unbending and gently (or not so gently) nudging the line into the desired place.  The technical aspect of using the tube cutter, flaring tool and bending tool are pretty easy.  My ability to visualize the spacial gaps and correctly bend the tube to achieve the desired alignment is not so good.  Oddly, I recall taking an Air Force placement/aptitude exam when I was in my early 20’s and being somewhat surprised at a low score in spacial relationships based on paper representations.  I think that that’s what’s going on here.  Oh, well.  Regardless of my intrinsic weaknesses, I believe that i have safe & functional fuel lines installed, even if they are not pretty or elegant from an engineering point of view.


IMG 3204

Fuel line from cutoff valve to bulkhead

IMG 3205

Fuel Line inside cockpit Tunnel

Note the Red Box fuel flow sensor.  The white wiring will communicate from the sensor to the aircraft avionics, but for now may be ignored.   The fore most line goes from the fuel flow sensor to the gascolator.  Recall that I had to use a  step drill through the aluminum stiffener that you see along the far right inside edge of the tunnel.  Apparently, I didn’t get the measurement exactly right (or the drill wandered a bit before biting in and drilling) and the nipple didn’t fit through the hole and into the cascolator as originally placed.  I used a Dremel tool and shaved the edge of the hole until it was more of an oval and the nipple was able to fit through the firewall.   

IMG 3206

Gascolator installed on firewall


Here’s the installed gascolator.  You can see the safety wire installed.  That took over an hour to get the wire threaded through the 4 screws and tight enough to be effective.   More to follow...

Thursday, May 15, 2014

28-04 fuel line, pump to cut off

One of my oddities is that I tend to do my documentation of this project at night / early morning when I’m at work and it’s slow at the hospital.  Since I’ve been on vacation for a week, I got a lot of work done on the plane and no documentation of same.  This is one of 6 pages posted at the same time.  I’m hoping to write up the textual descriptions in the next few days.



IMG 3199

 Fuel Line, pump to aft bulkhead

It’s not pretty, but it’s functional and safe.  The line snaked through the two bulkheads without too much hassle.  I got the fittings on without any trouble and threaded onto the valve.  You can see a bit of the thread sealant, which was sticky and gooey but other than that, not bad to work with.



IMG 3200

Fuel Line, midship bulkhead to cut off valve


Wednesday, May 14, 2014

28-03 fuel line, tank to pump

Another item that arrived while I was working (well, actually, it arrived as I left on my 1 day vacation) was the 3/8” tubing bender.  I successfully fabricated my first fuel line without significant drama.  You can see it attached to the aft end of the fuel pump and bending its way through the lightening hole in the floor.  The oval cutout in the floor has a bit of white stuff poking up.  That’s masking tape over the other end of said fuel line.  I’m not happy about the minimal clearance between the line and the edge of the lightening hole.  I’ve made a To Do to put a bit of caterpillar grommet material there to give me piece of mind.

BTW, the fuel tank also arrived, so I may install that prior to skins, too.

IMG 0004 2

Tank to Pump Fuel Line

23-02 Longerons

I bet you thought I had gone on vacation or something.  Well, you’re half right.  There was the usual “work is interfering with my life” for a week, but I did go out of town for a quick 24 hour vacation.  When I got back, I grabbed the new longeron piece that had arrived while I was working and went out the the garage to pound metal.

Take a moment and go back to read the 1st paragraph of  23-03.  OK.  As you can surmise, I botched up the longerons the 1st time I tried it.  I actually did the Left one properly, but it took the better part of a day to get my courage up to hit the damn thing hard enough to bend it properly.  It was a very tedious day with multiple clamping-beating-unclamping-clecoing the part-measuring-cussing and repeating the cycle.  Eventually, I got the thing done.

I didn’t trust my ability to hold pieces in my hand for delicate measurements, so I got a piece of 0.025” scrap and clamped on the arm rest appropriately and match drilled hole #1 and #8 (from the front).  These became my anchors and I took the time to cleco the arm rest on every time I wanted to evaluate my progress.

Suitably emboldened, but also tired and not realizing how tired, I fearlessly clamped the Right longeron in my vice and proceeded to whack the hell out of it.  I was very impressed that I had a patently obvious curvature when I finished the first pass.  It bent in two planes, as expected.  What wasn’t expected is that the two planes were not the intended one.  I didn’t pay attention to the orientation in the clamp and proceeded to bend it down (and it bent out) instead of in (and down).  Well, damn and double damn.  Swallowing my pride, I simply placed an order for the replacement ($20 + $20 S&H).  That’s when I went to do other chapters.  Returning to our saga...

Like the 2nd piece, this one bent much easier than the 1st.  Unlike the 2nd piece, I triple checked the orientation prior to applying hammer to aluminum.  The open-&-twist maneuver went very well, as did the introduction of the curvature.  I actually got the curve just about perfect with one pass of hammer blows at each inch (just like the book said to do.)  I ended up with about 4 or 5 inches of unwanted deviation downward.  

My bench vice has a feature to permit rotation of the jaws.  Unfortunately, that means that it’s got a tendency to rotate and no matter how much I tightened it down, trying to bend the longeron back into level by hand didn’t work because the vice would rotate.  I ended up taking it into the kitchen and (1) used the granite top as a level surface and (2) using the corner of said top as a fulcrum and just applied hand pressure until I got the longeron within 1/4-1/2” flat.  Bending the tail went a bit too far—about 6°, but it went back just as easily.  I used the trig trick from Homebuilt Help and calculated that 4° deviation over 6” was about 7/16”, and used a straightedge & ruler to determine what I needed.

IMG 0001 2

Bent Longerons, with attached arm rests

IMG 0002 2

Close up of Longerons with Arm Rests


In the top photo, you can see the atypical tools used in this operation: the protractor, the skin shim and the dead blow soft hammer.  Quite the adventure!

I’m going to stop on this chapter for now and do the installation of the rudder and fuel system, possibly also some wiring.  I could attach the vertical portions of the skeleton, but that would expose things to being bent or poking me in the eye as I work around the bottom of the fuselage.  For now,  I’ve conquered the longerons, which was a major emotional milestone, thus I’m content to move elsewhere for now.

Tuesday, May 6, 2014

24-02 Rollover Structure

This is one of those pages that looks pretty straightforward (well, it is actually) but took forever due to the plethora of holes that needed to be aligned, clecoed, final drilled, cleco-shifted, final drilled, un-clecoed, deburred (each hole x 4), countersunk, clecoed, riveted, cleco-shifted and riveted.  Took the whole day and late into the night.  I took advantage of the fact that everything was accessible during assembly and did some of the work for the Eyeball Light from page 40-13, but that page isn’t complete so it’s not being documented at this time.  


IMG 3178

Roll Bar and misc brackets

The brackets took about 3 minutes.  The roll bar took about 8 hours.  Whew!

IMG 3179

Eyeball Light mounting bracket

This will hold the LED ‘eyeball’ light for night flying.  It’s not pretty, but the bit of string that you see tied to the canopy latch will be used to pull the wires later.

Sunday, May 4, 2014

28-02 Fuel System hardware install

Continuing with the philosophical thread started by the longerons, I also decided that I was dreading working with the fuel system, since it’s another area of lack-of-expertise.  Best way to deal with putting something off is to dive right in, so I did.

IMG 3158

Fuel Pump installed in rear tunnel


IMG 3160
Fuel Cut-off Valve installed in cockpit
So, what did I learn?  A fair amount.  I learned how to recognize the various fuel fittings.  I bought some thread sealant (very thick, gooey stuff).  I learned that the threads all seem to turn freely for 3 o 4 revolutions, but then require LOTS of torque.  I learned that I had not taught Nick the meaning of fore and aft and then expected him to correctly orient the cut off valve when I clecoed it from the bottom of the ship.  (no worry, it came out with just two expertly drilled rivets and was re-installed in a jiffy.)
I was even thrilled to discover I could use my new flaring tool and make pretty good test flares on the 3/8” tubing that will be the fuel delivery system.  Lastly, I learned that I did not pay attention when I ordered the tubing bending tool, and that it is too small to accept 3/8” tubing.  Oh, well.  That’s the reason I dived in so early—there’s plenty for me to do while I wait for Harbor Freight to send me a larger one.
On to the rudder pedals!
... or not.  Guess what’s back ordered?  Torque tubes for the brakes.   I guess I’ll work on the roll over structure today.

23-03 Roll Bar Attach Plates

  Stay tuned for the posting of 23-02 (Longerons).  I realized that, like many other posters on VAF, that I was reluctant to tackle the longerons for whatever reason.  My current plan is to install whatever subsystems I can before putting on the skins, but there may have been some avoidance in doing the longerons in that decision.  Logically, what would be the worst thing that could happen?  That would be doing everything else possible, finally tackling the longerons and then screwing them up and causing a delay while I waited for new parts to arrive.  Solution:  tackle them now and if I screw up, order the replacements and get back to work on things that can be done.  Well, that’s what I did.  I’m currently waiting for another 9’ foot section of AA125x0.75x0.75.  Like I said, stay tuned for that posting...

On to today’s work.  After feeling bad about messing up the right longeron, I wanted a straightforward page to feel like I was back on track, so that’s today’s project.  The only question is one that I’ll post to VAF about the discrepancy between the book and the parts.  The book calls out 6 LP4-3’s, but there are 7 holes in the parts that really seem to be appropriate for another LP4-3.  I placed a cleco to be a visual reminder of the questionable hole and will see what the collective wisdom of VAF says.


IMG 3153Roll Bar Attach Plates and Mid Fuse Brace

Note the upright cleco marking the 7th hole. It’s not mentioned as Do Not Rivet, which is what I would expect.  On the other hand, the manual clearly calls out 6 rivets, not 7, so I’ll just wait to hear back from VAF.   Note also the inverted clecos—those are Do Not Rivets.   

IMG 3154 Roll Bar Attach Plate

5/4/14 addendum

The consensus is that that hole will be drilled out later to feed wiring through for the lighting kit, although that doesn’t quite make sense that there are holes on both sides.  Nonetheless, I’ll wait until I’m done with the wiring and then plug whatever’s left over with a rivet.