Pneumatic Rivet Puller Malfunction.

Last night while finishing up the right anti-servo tab, the rivet gun jammed and I had to finish pulling the rivets by hand.  Pulling any significant amount of rivets will make you appreciate the air tool.

A big thank you to Bob at Avery Tool.  This gentleman has been extremely helpful with any technical questions.  He quickly guessed that the problem was multiple rivet shanks collecting in the exit tube and jamming up the jaws that engage the rivet shank.  He then explained how to disassemble that section of the tool and clear it.  I did as instructed tonight and the rivet puller is back in business.

You can buy the same (or similar) tools many places, but this type of service after the sale really sets Avery Tool apart.  I highly recommend them.

The completed assemblies are starting to add up.  So far to date:

• Vertical Stabilizer
• Rudder
• Right Anti-Servo Tab
• Left Anti-Servo tab

Next up....  The Horizontal stabilizer.  This piece appears to be a bit more involved than its predecessors.  This seems to be the theme while building this kit.  The skills you learn in one section are built on for the next.  For the most part, I am very impressed with the development of the kit and its plans/assembly manual.

Build time to date:  56.3 hours

Moving Forward.

The Rudder

The Rudder is complete.  There was really only one challenge in completing the Rudder assembly.  The area where the upper hinge brackets mount to the rudder spar is assembled using some larger solid (squeezed) rivets.  The lengths are longer than the smaller solid rivets used up until this point.  While trying to squeeze these rivets, the shop head side (the side that does not have the factory finished head) kept squeezing off the the side. I probably had to drill out 10 solid rivets before I recalled reading a post on the Vans Airforce website a few months ago that appeared to apply to my situation.   That evening I spent some time relocating the forum post and the next day I went to the hardware store and purchase some 1/8" inside diameter clear plastic tubing; the kind you might see as fuel line for a remote controlled airplane engine.  By placing a small section of the tubing (slightly longer that the shop head side of the rivet that protrudes through the material to be riveted) over the shop head side of the rivet, the rivet shank it held on center when the rivet is squeezed together.  Additionally, the rivet tool surface contacts the tubing prior the the shop head of the rivet and when squeezed applies pressure to the the base of the materials to be riveted together; thus ensuring a tight contact point of the pieces prior to expansion of the rivet.  Thanks the Lord for engineering type guys that have built aircraft before me.  This simple modification of the process is something I would have never figured out myself.

Some pictures of the rudder.

The Anti-Servo Tab(s)

An anti-servo tab, or anti-balance tab, works in the opposite way to a servo tab. It deploys in the same direction as the control surface, making the movement of the control surface more difficult and requires more force applied to the controls by the pilot. (source wiki)

Basically, the anti-servo tab(s) moves in the opposite direction of the elevator in order to balance the control forces when pulling the nose of the aircraft up or pushing it down.  My Cessna does not utilize this counterbalancing system for the elevator control.  It instead uses a section of the elevator that is controlled by a trim wheel.  Without the use of the trim wheel, the control forces required to make elevator inputs can be substantial.  My guess is the use of the anti-servo tab(s) aids in the balanced feel of flying the Vans RV-12.

There are two tabs (a left and right).  They are mirror images of each other.  I have completed the left and am in the process of the right.   Picture below.

  
Spring has sprung!

The shop is getting a bit warmer.  In a month or so, the temps will begin to become an issue. I need to explore ways to cool things down before summer arrives.  Mackenzie and Allia don't seem to mind the warmer weather though.

Back in business.

Yesterday my friend Pedro came by and helped me skin the VS assembly.  There were a few key points where his extra set of hands came in useful aligning some key holes on the leading edge of the assembly.  Took about an hour and half and we are now back to the point where the wheels fell off the bus last month.  So basically a month delay and another $300 plus dollars and it is time to start moving forward again.

Replacement parts arrive.

The replacement parts arrived Friday afternoon.  I unpacked, inventoried and began work Saturday.  Before I knew it six hours had passed and the VS (part deux) was well underway.  Another three hours today and we have a completed skeleton.

This time I went ahead and mounted the upper rudder hinge bracket prior to skinning the assembly.  I had to make some minor adjustments to the mounting holes in order to get he bolt holes to line up on the rear spar and the brackets.  for the life of me I can not figure out why Vans has this step after the entire assembly is buttoned up rather than earlier when a problem could be addressed much easier.

I will skin the assembly this week and be back where I was a month ago.  I'm guessing this will not be an isolated incident of 2 steps forward and one step back.  Building an airplane is a marathon not a sprint.  A fellow builder gave me a good piece of advice in the form of a question.  How do you eat an elephant?  .....one bite at a time.

New Parts for the VS Assembly on the way!

Getting the parts.
It took a while, but the new parts for the VS assembly "Part Deux" are on the way.  Van's has a reputation for being very good at support after the sale.  I am hoping that my recent experience is an isolated incident.  I waited 3 business days for a response to a tech email question and over a week for a replacement parts order to be processed.

The knee.
In the mean time, I experienced another setback with my right knee.  While nursing issues with my meniscus for a few months, it popped again last week and left me semi-crippled (and squealing like a child) for the second time in 60 days.  My amazing wife successfully managed to have my surgery pushed up to this past Friday (initially scheduled for mid April).  Friday I had the surgery and appear to be healing well.  Worked out to be a good use of the building downtime.

New hours of operations.
I'm looking forward to getting the replacement parts in and cranking back up the assembly plant.  In the interest of continued marital bliss, I am going to make a voluntary self-adjustment to the operating hours of the assembly plant.  Regular operations will be on Tuesdays and Thursdays after work.  Build will also take place other times when opportunities present them self w/o interfering with family time.  Anyone who wants to help, or just stop by and visit to take a look, is welcome to swing by on Tuesday or Thursday evenings.  I'll be the guy limping around (in the near term).

Highs and Lows of Aircraft Building

The Highs

Friday evening my brother-in-law hung out with me in the garage as I riveted one side of the VS skin to the VS skeleton.  It was quite a sense of accomplishment to remove the last cleco and pop the last rivet on one side.

Saturday I took Carice's Uncle John Glancy for a ride in the Cessna.  It was a nice day but breezy.  On takeoff, winds were 290 16 knots gusting to 27 knots.  Not a big deal for departure on 27L, just kept it in ground effect a bit longer to build up airspeed incase of a gust drop.  We took a nice flight  south off the coast.  Visibility on the Vero Beach reefs was top to bottom.  Mental note - good time to get some lobster.  Came back to MLB over the river for a left base entry for 27 left.  Winds were 300 16 knots gusting to 27.  Flew final at 75 instead of 60 and landed with two notches of flaps instead of 4.  Nice landing.  Managed to take a first time C172 passenger up and keep him comfortable from takeoff to landing.  Success.

Once safely on the ground we made our way to the Cunningham aircraft manufacturing facility (the garage) to show off the plane build.  We pulled a few rivets on the other side of the VS.  I ended up finishing the riveting of the VS saturday afternoon.  I was a happy aircraft builder!

The Lows

Sunday there was one final step in order to be able to set the VS assembly aside and move onto the rudder.  I had to bolt the upper and lower hinge brackets to the rear spar.  No big deal I thought.  Long story short, some how I cross threaded and/or stripped two of the bolts and they would not tighten to the torque settings called out.  they just kept spinning when fully inserted into the nut plates (riveted to the other side of the spar - inside the VS assembly).  I decided to remove them and check the threads.  No luck, the bolts will not back out.  They just spin.  Very frustrating!

I decided the only hope of getting these bolts to unscrew was to open up the skin I just riveted on (it looked so pretty) to access the back of the bolts.  I hoped that if I placed pressure on the back side of the bolts, the threads might catch and I could unscrew the bolts.  about half way through drilling out the rivets I need to in order to peel back the skin, my drill bit walked of the top of a rivet and placed a nice scar on the skin.  Frustrated, the next rivet I drilled out was drilled off center and I wall-erred  out a rather large oval from what used to be a circle (this is very bad).

At this point I stopped and took some pics to send to Van's builder support.  I was hoping to salvage the assembly some way.

Tuesday (today) I still have not heard back from Van's on my email.  I gave the benefit of the doubt that they were closed for President's Day yesterday.  I was surprised (and disappointed) that I did not receive a response today.  None the less, I opened up the rest of the skin on one side and tried my technique to remove the bolt.  It did not work.  I then began trying to drill out the bolt.  These bolts are HARD.  It was eating drill bits.  Bottom line, I have decided to order new parts and rebuild the assembly in its entirety.  It would just bug the crap out of me if I didn't anyway.

The next build day I will move onto the Horizontal Stabilizer (HS).

Vertical Stabilizer - ready to button up.

Tools, tools, tools.

Remember those tools I was talking about?  Well one of the tools I need to de-burr/smooth the edges of the large aluminum skins is a "double edge de-burring tool".

  I ordered it online sunday evening so it should have shipped Monday.  I was expecting to receive it on Wed after work, but no luck.  Now it is Thursday evening and I have hit a stalling point.

The VS is all ready to button up with about 150 blind pulled rivets each side.  Problem is that I need to de-burr the edges of the skin before riveting it together.  Here are a few pics of the skeleton going into the skin and the assembly cleco'd together (a cleco is a temporary spring loaded fastener).  This is as far as I can go on the VS assembly until the tool arrives.

On to the Rudder.

Without being able to go any further on the VS, I decided to move onto the Rudder.  The rudder is the aft extension of the VS that pivots left and right from the rear spar of the VS.  This is linked to footpedals in the cockpit and controls the airplane's horizontal L/R movement.  Anyway....

The rudder assembly goes together much like the VS assembly.  The main spar is matched up with some spar caps.  These are smaller pieces that nest into the main spar to provide additional support for areas where hinges mount or areas that will carry a higher stress load.  They can be seen in this photo along with a hinge (temporarily mounted with clecos).

Additionally, the rudder spar has a control horn attached to the bottom of it.  This is where the control linkages will eventually connect the rudder to the cockpit control pedals.

From this point, the rudder ribs will attach, perpendicular to the rudder spar, to create the skeleton of the rudder.  The skeleton will then be slipped inside the rudder skin and riveted together; similar to the VS assembly.

Seems simple and straight forward.  The devil is in the details, or should I say de-burring.  Every hole has to be final drilled, then de-burred.  Every spar and rib has to have all edges smoothed and de-burred.  This is because fine cracks along the edges can turn into small cracks over time, which can turn into large cracks.  You can get the point from here.

Truth is, this aircraft will not be aerobatic and will be flown more like a sport sedan than a race car.  The stress loads I will eventually place on the aircraft will likely never give it an opportunity to present a problem.  However, I am one of those people that believe in planning for the worst case scenario and enjoying when it doesn't happen.

Another road block.

The next step calls for the rudder spar to be test fit to the pivot hinges on the rear spar of the completed VS assembly.  Well, no completed VS assembly, so no way to do this.  I can't move forward with the rudder until it passes the test fit.  Once the spar caps and hinges are riveted into place, it would be a royal pain to have to change/adjust it.

I could move onto the next assembly or start cleaning up all of the rudder ribs in preparation for later steps that involve them, but the anal retentive side of me is starting to get sketchy about moving too far past multiple uncompleted steps.

Carice's Aunt, Uncle and Cousins are coming into town for the weekend tomorrow.  There has been talk about taking the boat out on the river, so I will be taking a few days off building.  Hope everyone has a good "Hallmark Holiday" aka Valentine's Day.