Wing Miscellaneous

First, a brief narrative for my delay in posting more updates.  In a word - Eggenfellner.  In more than a word - Jan Eggenfellner and Viking Aircraft Engines...and a long overdue shipment of RV-12 wing tanks.

Jan decided he did not like the thin-walled wing tank design (not to mention any other problems that might be lurking, like the lack of sufficient venting and specifically a siphon break).  This original design utilized a TIG welded rolled sheet of thin aluminum of a custom diameter.  The custom diameter would maximize usable fuel for the tanks that rest in the wing rib lightening holes.  Since abandoning the original design in the January/February timeframe, there has been little progress revealed to purchasers.  He has implied the use of regular extruded tubing instead of the welded tanks, which will result in a significant reduction in tank volume and increase in weight.

His new project involving a Viking 135 engine, as he calls it, is a V-configuration motorcycle-derived engine of 135 horsepower.  He is currently fitting the prototype engine on a highly modified Zenith Cruzer....and it is taking away from everything else.  Combine this distraction with preparation to wow the Sun n Fun airshow crowds along with the recently "upgraded" oil tank for the Viking 110 (Honda) engine that appears to have some teething problems and you have delays upon delays.  And I'm ticked!  Texan speak for angry.

The only response so far to my email inquiries has been a single post stating wing tanks will ship at the rate of 1 per week.  Don't know where I am on the list, but it's not for lack of asking.  I hope to hear something soon.  The one builder who has received his tanks, submitted a one sentence review to the Viking portal stating something to effect that the welds look great....okay, that's helpful - not.

Alright, enough of the negativism.  I'm just mad about the lack of progress.  I have done a few small tasks as follows:

First was the prep for the install of the landing light in the right wing leading edge.  Apply the template to the leading edge skin, aligned with the appropriate rivet holes.

Next, go slow and make the initial rough cuts followed by the more precise cuts with some dremel metal working bits.

The finished cut out for the landing light!

 
Below are two of the mounting brackets with riveted doublers for the wing tip landing light.

Now, we switch over to the left wing because there is an existing inspection hole/cover for the stall warner installation.  Below is a shot of the pitot tube with it's simple circular mount aligned with freshly drilled hole in the wing skin.  It took a bit of head scratching to arrive at my ideal location, which was in relatively close proximity to the adjacent wing rib.

A profile view of the pitot tube's improper orientation.  It will have to be "bent" such that it remains parallel to the freestream air and not pointing upward (remember, it is inverted in this picture).

Looking at the pitot from the other direction.

The pitot projects into a hole of a small angle bracket that will be riveted on the wing rib with a doubler (not shown).

Primed parts: wing rib doubler, wing skin doubler and the previously shown angle bracket.
 

Wing skin doubler from the inside, cleco'd into place.

Hole drilled and deburred.

Skin doubler with pitot mount riveted to wing skin.

Pitot angle bracket/rib doubler cleco'd into place awaiting rivets.

Final assembly awaiting the skins and pitot tube.

The next mini-project of this installment is stringing the wiring for the lights and stall warner to both wings.  Shown below is the right wing and the mounting points for the stall warner.

And the root end of the same wing showing the termination of the harness about to be installed on the rib.

Full span shot of wiring of right wing.

The final installment of this blog is the second of two firewall stiffeners.  The Vans upgrade was already installed on the passenger side of the aircraft and I elected to repeat one for the pilot's side.   I never took any pictures during the process, so the finished product is all you get.

Hopefully the next blog will find me in a better mood with some real wing progress to report...otherwise it's back to other incidental stuff with the fuselage and cowling, which I was hoping to defer to the end of the project.

Van's Service Bulletin 14-12-06

Cracking F-1206F Bearing Bracket Brace.  Van's published this service bulletin at year's end of 2014.  Cracks have been reported propagating from the aft rivet hole in the side flanges of the F-1206F bearing bracket brace.

I ordered the small kit containing a new bracket and a new part, a pair of bearing bracket angles and a handful of solid and blind rivets.  Since I again removed the temporarily-fastened tailcone from the forward fuselage, I had access to the bracket, so I figured it was time to get this small task done.

 The new bracket with new angles solid riveted into place shown below.

I never took any pictures of the original bracket which was installed between the two ribs shown below.  The new bracket looks to be identical to the original with the exception of the new, separate angle brackets.

The new bracket/angle assembly now installed as shown below.  I have not reconnected the flaperon brackets, which were removed to make easier access to the ribs.  Another pesky little job is completed!

 In hindsight, I am very happy that I did not have to climb into the baggage compartment of a completed airframe to drill out the 10 blind rivets that fasten this bracket to the ribs.  It was not easy, even with the direct access I had available.  Guess I dodged another bullet.

Flaperons

As the main wing construction has been halted, awaiting delivery of the Viking Aircraft Engines' RV-12 wing tank conversion kit, I began work on the flaperons.  But what is a flaperon?  Simply put, on an RV-12 it is a wing trailing edge control surface that functions both as a flap and an aileron.  A mechanical "mixer" inside of the center beam of the aircraft provides a means of accepting both control inputs (flaps handle movement and lateral movement of the control stick) to provide separate and distinct movements of the flaperons.

First task after all surface prep and priming was complete was to assemble a left and right nose rib to its respective bracket assembly.  The assembly on the right was touched up with some rattle-can primer after a solid rivet had to be drilled out.

Next, the actuation bracket's inboard holes were riveted onto the inboard end of the flaperon spar, as shown below.

On 2 locations of the spar, the flaperon pivot brackets were also attached to the spar.  These will serve as some of the hinge points of the flaperon to the wing.

My lovely wife gets into the action of riveting some ribs onto the flaperon spar.

 A shot of the finished flaperon spar, awaiting its tail and nose skins.

 Close up of the actuation bracket and unnamed bracket, which is attached to the inboard nose rib.

Meanwhile, down at the outboard end of the flaperon, resides the counterbalance (steel tube) that is attached to the outboard ribs of the spar.  The trailing edge skins are getting ready to be riveted in place.

 A shot of the inboard end of the counterbalance is shown below.

With the trailing edge skins in place, its time for the nose skins to be clecoed in place and some final match hole drilling of the nose ribs.

 Hard at work admiring myself in the reflection of the bare skins....and sometimes riveting too.

It really goes together pretty smoothly; no real hiccups of any kind appeared.

Looks like I'm back to the waiting game as I'd really like to have the wing tanks in house before skinning the wings.  There's always the lighting kit...perhaps it would be easier to make the cutout in the wing for the landing light now, before that skin is attached to the wing.  We'll see, so stay tuned.

Wing Kit, Part 2

Onward and upward with the next installment of wing construction!

Some of the final preps taking place for readying the rear spar.  In this case, an attach angle is riveted to the spar that will be used to form an attachment for the underside of the wing tip...complete with gray, rattle-can, self etching epoxy primer.

On the other end of the rear spar is the business end, which mates to the fuselage fitting.  Note the mixture of solid and blind rivets.

 The nose ribs need a little love too...in the form of some "nutplates", which is a liberal use of the term.  The kit assembly instructions show only 1 conventional nutplate in the drawing, along with a note reading "dimple, 2 places/nutplate".  Later on, the verbiage refers to a nose rib with 3 nutplates and so the head scratching began.  Finally figured out (between 3 of us) that it meant another conventional nutplate AND the W-0028 doubler plate....overthinking at it best/worst.

Back to the tail ribs and match drilling through the hinge ribs and hinge bracket assembly for a perfect fit.

Two of the tail ribs feature doublers, as shown here.

Young Padawan of the Fighting Cyclone clan (ISU) but with an aerospace engineering degree!  His older counterpart hails from the cold north of Minnesota and occasionally winters in the warmer confines of the not-so-warm south.  Its awesome having relatives (nephew and brother-in-law) who actually get excited about the prospects of menial labor in a cold dark garage (hangar)...all for the sake of seeing fragments of an experimental aircraft come together - my kind of peeps!  Thanks again Brian and Stan.

First tail ribs getting cleco'd and riveted to the back side of the main spar.  Four hands in a space of a few square inches....and at times there were 3 of us with 6 hands in the same space....but we were effective.

The supervisor doing a quality check as the rear spar goes onto the end of the tail ribs.  Older guys rule!

 Surrounded by a sea of ribs.

 

The stall warner goes together with a small plate, an arm and an assortment of thick, thin and larger diameter washers along with 2 types of machine screws and stop nuts.

Awaiting placement of the arm and stop nuts, washers.

Up close and personal against the backdrop of the instructions.

Same song second verse - that would make this the right wing!  Eureka - so that's why the hat is on forward!

The young aerospace engineer enjoyed a brief analysis of the multiple layers of varying length of spar cap material, not to mention the varying cross section of the web, so I took a couple of shots to preserve the detail for myself.  It really is a nice piece of work from the factory.

 The final touches going toward the install of the rear spar of the right wing.  Hat issues...

Nose ribs going onto the spar.

All of the help was great.  At one point I just had to go inside and put the finishing touches on a load of laundry and brag to my wife that the airplane was building itself - awesome!

Back side of the root end of the spar showing ribs, spar web and caps detail - pretty!

Close to a stopping point.  Since I have opted to replace my fuselage fuel tank with Viking Aircraft's wing tank conversion, I am halting the construction process, so I can work on the wing skins, before they are installed.  There will be some access hatches and filler neck cutouts to be made; much simpler if not attached to the wing structure.

Some final detail shots of the front spar, prior to riveting.

 More exciting stuff to come as the drama builds.