(page 54-01) Firewall stiffening kit

                                                                           
The stiffening kit is optional and cheap, and it would make no sense to not do it at this stage of the build.  It supposedly prevents some sort or rumbling noise experienced by some builders. 

It involves installing the diagonal brace shown here on the firewall and two similar braces inside the side skins adjoining the firewall.  This prompted me to go ahead and begin installing the side skins, which I had been avoiding, fearing the skins would make complying with the landing gear service bulletin more difficult.  The landing gear service bulletin requires drilling holes in the center channel using parts in the finish kit as templates.  Problem is, I don't have the finish kit, and therefore can't drill the holes.  All flying 12s had the SB done with the skins on, so I'm proceeding with it.

The procedure for the stiffening kit called for removing the bowl from the gascolator in order to drill out an existing rivet, which meant removing the safety wire I had carefully installed and am quite proud of (experienced builders would find this humorous).

I avoided this by loosening the fitting from the gascolator through the firewall along with removing the AN3 bolts holding the gascolator to the firewall.  I then could rotate the gascolator counterclockwise enough to drill out the rivet.

Massive progress coming soon. 

I turned in grades today for the two classes I taught in summer school (Thermodynamics and Heat Transfer).  If you'll notice the dates on my posts, I've done nothing for many weeks.  Summer school is the reason.  It essentially removes five weeks from my life, but gives me part of the money required to do things like build airplanes.  The spousal unit (my beautiful and overworked wife, Karen) is leaving for five weeks to lead a hike through the Rocky mountains in Wyoming (grizzly bear country!), so I have no excuses.  I plan to work at least eight hours each day on the airplane.

My airplane got the bird!                                                          

I left the garage door open and unattended for approximately four hours yesterday, and the result is shown in the picture.  Birds are the hardest-working little buggers I've ever seen.  I never saw the

,

birds who did this, and I hated to move the nest, but unless I was willing to suspend work for about a month I had no choice.  At least they hadn't managed to lay eggs yet.  Another pair of birds, this time Carolina Wrens, were aggressively trying to build a nest in the rafters while I worked in the garage not 10 feet from them.  I tried flushing them out by waving a broom around without success.  Finally, I enlisted the help of my pet owls, who were more than willing to stand guard at the door, looking quite fierce and intimidating as they swayed to and fro in the breeze.  So far, so good.  No more birds in the garage.

On a happier note, the fuel lines are finished.  The bad part of this is that while installing the fuel lines I discovered that I had routed the brake lines through the wrong grommets in one of the bulkheads, requiring that the long lines that go from the master cylinders on the rudder pedals back to the landing gear had to be redone.  I remember double-checking this as I did it in order to avoid just such a fowl up.  I managed to do it anyway.  This, of course,

means I get to either do the boiling-water trick one more time or try something I read today on the forums that was supposedly proposed by none other than Ken Krueger: run a #29 bit through the first 1/2 inch of brake line, which allows the inserts to be pushed in with no heat.  This sounds too easy, makes too much sense, seems too obvious, and therefore probably won't work.

While I'm waiting on the new brake lines to arrive, I started on the side skins, the first step of which involves removing a thin strip of metal in order to form the slot through which the wing spar will pass.  The manual says this can be accomplished with tin snips.  My initial attempt says this won't work (at least with my skill set).  I wasted an hour looking for my nibbler, which is the obvious tool, and gave up for the night.  Ordered a new nibbler from Spruce.  Very frustrating.

(5-27-13) Update!

Using a #29 bit to ream the ParFlex makes pressing the insert into the tube a snap.  It's still an interference fit, so it's plenty tight.  It's irritating thinking about all the headaches with the boiling-water routine that I could have avoided.

(Page 28-03) Fabricating fuel lines..........                  

...is the easy part.  Installing them is a whole 'nother smoke.  Right off the bat I learned two important things:  The nut for the fitting will go around a 90-degree bend, the sleeve will not.  This, of course, means that the sleeve must be on the flare side of the bend as the bend is being made (false start number one). 

The picture shows the first completed part and three short pieces of tubing (now scrap) which resulted from my first three attempts to fabricate the part.  Actually making the bends is childishly easy using the tool (purchased from Spruce) shown at the top of the picture.  It was impossible, however, to make that first 90-degree bend (shown on the lower right of the pic) as close to the end as shown in the full-size picture in the plans.  That extra inch or so didn't matter when installing the part in the fuselage.  All of the parts such as this one which can be fabricated independent of the fuselage structure should be easy.  No so for the parts which require one end to be flared after passing through the grommets in the bulkheads.

The tube going from the fuel pump to the fuel valve requires that the aft end be flared and fitted with the sleeve and nut before being installed in the fuselage.  The un-flared forward end is then passed through three bulkheads with grommets (it's a tight fit) and ends up near the fuel valve to which it must attach.  The only way to accomplish 

this is to alternate between bending and straightening short sections of tubing while feeding it through the holes.  The short piece of tubing at the forward end had to then be cut to length (be sure to have a close-quarters tubing cutter -- the one shown in the first picture won't come close to fitting) and flared (see picture at right) in a very small space.  I could only do this by hand bending the tubing out about 45 degrees, installing the fitting, then hand bending it back into alignment with the fuel valve fitting.  I'll be holding my breath when I pressure test this.

Two small deviations from the plans could have made this process much easier.  The s-bend between the fuel pump and the aft-most bulkhead could be moved aft approximately six inches without affecting anything.  This would allow the whole tube to be slid forward that amount, giving much more room to install the forward fitting.  Also, riveting the fuel valve assembly could have been delayed, allowing the valve to be removed (it was clecoed in place).  It's a real learning process.

One last piece of advice:  When the plans call for cutting the tubing to a particular length, add at least an inch to the callout.  Trial fit the piece, mark the correct length, then cut.  For the tube which connects to the gascolator, I cut to Van's specification, did the bends, flared the ends and installed the fittings.  Ended up 1/2 inch short.  One more piece of scrap.

My crowded shop..........                                                 

With the arrival of the wing kit, the lack of space has become critical.  The fuselage is on its side on the table, awaiting installation of the fuel lines

(not looking forward to fabricating the lines with all the exacting bends).  The parts from the wing kit are distributed about the shop, with the wing skins on a platform suspended directly above the car.  The stabilator is standing on its end leaning against the tail cone (not visible in this pic) between the car and the fuselage.  The plan is to move the tail cone and the stabilator to the attached garage and build the wings on the saw horses between the car and the fuselage.  It seems that most people build the two wings at the same time, and maybe the plans call for this, but clearly I don't have space.  One option would be to evict the car, but I can't bring myself to do that.  It has spent very few nights outside since I picked it up at the factory in Bowling Green.  The Spousal Unit (my beautiful and long-suffering wife, Karen) offered to relinquish her spot in the attached garage, but I know better than to accept that offer. 

The other slot in the attached garage is occupied by my antique, which I'm going to continue working on any day now (as I've been saying for several years -- I frequently ponder the phrase "too many irons in the fire").


Brake lines continued...                    

The forward ends of the brake lines require installation of the insert, sleeve and nut (see March 10 post) in the shop rather than in my kitchen, a result of having to thread the lines through the bulkhead grommets, which can only be done before the ends are installed.  The boiling water required for press fitting the insert into the line was accomplished with the rig shown.  A large Kronenbourg beer can, which for unknown reasons I had saved for the last 20 years, was cut in half and pressed into service as a pot (it was explained to me that the kitchen pots were not appropriate for this purpose).  I still had difficulty getting the inserts to press in all the way, even after coating them with dry Boelube.  I can't be the only builder with this problem, although I haven't heard anyone else complain about it.

 

Redneck respirator........                                                           

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Being born and raised in South Carolina, my neck is inescapably a bit pink, so I don't always  go for the most sophisticated solution to the problem at hand (part of the reason I didn't buy a Porsche).  So to avoid inhaling paint fumes, rather than opting for the Hobby Air rig (~$600), I'm using a 40-foot length of corrugated PVC attached to the mouth piece from a snorkel.  Breath in through the mouth, out through the nose, don't get out of phase.  I used this method spraying two-part epoxy on a previous project and escaped unharmed (as far as I know -- my lungs may be Cub yellow inside).  I'm using a bit of nylon hosiery on the other end to keep critters out. 
                                                                                            For the interior, I'm using rattle cans exclusively for both priming (a combination of NAPA 7220 and Rust-Oleum self-etching primer) and for the top coat (enamel).  I want a lighter color for the dark places (foot wells), so I'm applying a clear enamel over the 7220).  I want a medium-to-dark gray for the visible parts of the upper portions (roll bar, side rails, etc.), but am still unable to find anything suitable that's not a primer rather than top coat.  Since I'm going with a full interior, a lot will be covered but there's still a lot of visible metal.  I'm assuming it's OK to leave some of the hidden-from-view interior parts in primer with no top coat.

 

Why I'm making no progress.......                            

Years of abuse of my rotator cuff (tennis, lots of other sports) culminated in tearing the muscle off the bone while sqeezing hundreds of solid rivets for the airplane build.  The surgical repair (four weeks ago) involved re-attaching the muscle to the bone with dozens of plastic anchors.

The really bad part is that I have to wear the sling for six weeks, with no load being applied for ten weeks. Kinda makes it difficult to get much done on the airplane.  Being right handed, I'm having to write on the blackboard lefty, reach across to shift gears with my left hand, brush my teeth left handed, etc.  Not fun. 

Of course, it's just my luck that Van's, on April 1st, announced the availability of a product which would have prevented the shoulder damage.  Van's AN470 Rivet Spray removes the need for squeezing, bucking or pulling rivets.  This product is simply sprayed onto the rivets after they've been placed in the holes, allowed to "set" for a period of time, then, as if by magic, they form the correct shop head and you're done. ;-)

(page 27-04) Brake line fittings.........                                     

Getting the brass inserts fully inserted into the brake lines is proving to be a bit of a problem.  As instructed, I put the fittings into a pan of boiling water, then tried to press the inserts in, with results as shown.  They're about 1/16th inch away from being flush on each fitting.  I tried repeatedly, same outcome.  I'll next try adding salt to the water in an attempt to raise the boiling temperature, but my calculations show I'll get a max temperature rise of about 2 degrees C, probably not enough to matter.  We'll see.   

                                                                                

Update (4-12-13)         

 

The fuselage kit comes with two 15-foot pieces of plastic brake line.  From these, two pieces a bit under eight feet must be cut, along with various other shorter lengths.  I cut several of the shorter lengths first, and ended up unable to make the two long pieces.  One long piece must be cut from each 15-foot length.

 

Van's supplies interchangeably two slightly different kinds of tube.  One has a yellowish hue and a different 10-digit number at the end of the designation.  They're both Parker Parflex with the same dimensions.  The one with an ending number of 006125903 was much easier to get the inserts into (see above).  When I reordered the line, I tried unsuccessfully to specify that one.  The lady at the desk showed only one part number.  I'm hoping for the best.