Sunday, May 19, 2013

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.

Sunday, May 12, 2013

(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.

Wednesday, May 1, 2013

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.