Horizontal Stab - Part III

Have been plodding along well.  Both skins are fit, and the entire assembly appears straight, and without twist.

My jig appears to have worked very well.  Sighting down the leading edge, it is perfectly straight.  I will need to modify it for riveting, but the concept is perfect.

So now it is on to disassembly, and deburring.  Then the spar cap strips need to be shaped and fit inside the forward spar, and then the aft attach bracket needs to be fit and drilled to the aft spar.

Once those last pieces are done, then it will be cleaning, alodine, and priming.  Then riveting!

Horizontal Stab - part II

Moving along on the Horizontal Stabilizer (aka HS).

Part I was getting all the spars and ribs straight, and cleco'ed up.  This was pretty simple.  Then came the modification of the centre ribs to allow room for the 'spar web' in the middle - again, pretty simple.

Then comes putting the right skin on.  Not simple, not straight forward.  You think its just lay the skin on, put it in position, and go to town... no so.  The 'jigging' process basically has to take the bow OUT of the spars.  So, I turn to the Glastar.net forum - which is an AWESOME source of wisdom.  Lots of guys have been here before, with lots of pics and advise.  

So you basically have to build a jig to hold the spars straight in both axis AS you line up the skins.  

Lots of swearing, thinking, and reading...

So here was my solution.

• My workbench is level, with very straight edges
• I made some blocks out of 3/4" ply that go in both the horizontal and vertical axis so I can butt the spar / skins up against it.  I know those 2 axis are straight (or at least I sure hope so).
• I clamped the bottom of the aft spar into that L brace with wood clamps and blocks (of which I have plenty).  Now I know that the aft spar is straight in 2 axis.
• As luck would have it, a 2x4 on end match up perfectly on the forward spar.  I clamped the right outboard end, and 2/3rd of the way down
• Using the level method in the manual I verified lack of twist at every rib location along the way.

Pics below.

Going to give it a rest for the rest of the night and recheck for twist tomorrow before I commit to drilling.  Once the holes are in, "it is what it is".

The forums has a variety of ideas, from building a steel truss work, to L channels, to standing it on end.  I have no doubt these are all valid approaches.  Bottom line is you need a straight / flat reference to butt everything against, with a steady reference from end to end to make sure the entire structure is straight / twist free.

Time for a break, and a double think before committing.  The drilling will go fast.

Horizontal Stabilizer, Day 1

Onto the next piece... very exciting.

The horizontal stab goes together from a framework standpoint pretty quick.  All the pieces are pretty much ready to go except for deburing, etc.

Nose and main ribs cleco'ed to the forward spar.

Rear spar cleco'ed on to the main ribs.

The holes in the forward spar had to be drilled with #40, and the rear spar #30.

Next is taking out the main ribs in the centre and putting in the doublers.

These all had to be drilled out to #30.

Next is shortening the main ribs to allow for the doublers.  The rib forward flanges are cut off, and replaced with an aluminum L bracket.

Great way to spend a Sunday afternoon...

Rudder (mostly) complete!

Finished riveting the rudder today.  Everything is done except the left skin to forward spar, and tip rib.  These will be riveted once the pre-close inspection is done by MD-RA at some point in the future.  The inspector needs to be able to see into any structure before close.  I am a little worried as between the aft spar and trailing edge are closed up, but all rivets for that section is viewable, and there is no structure between those components, so I **think** it should be fine.

To be honest, I was very apprehensive about riveting.  I would stare at what had to be done A LOT before actually starting.  Learned a lot of good tips along the way:

1.  I bought a rivet removal drill tool.  Makes it easy to get a bent rivet out.
2.  Don't rush.  Make sure you know what you need to do before starting.
3.  Drive some test rivets on scrap material before starting a riveting session.  Make sure the gun is setup right.  Put the gun on a block of wood and get a feel for the trigger (to make sure the air pressure is right) before you start.
4.  Don't be afraid to use blind rivets.  If I think I am going to bugger up some very expensive parts because of limited access, use a blind rivet.  I already had to make a couple small replacement parts because of mistakes.

Final product below... overall I am happy with the results.

Now I can dismantle the rudder jig, and start on the horizontal stabilizer.  The wing kit arrives in 79 days, and I want to get the horizontal stab, elevator and trim tab done (or ready for pre-close) before then.  Considering it took just shy of a month on the rudder (with learning curve), I think this is doable.  Fingers crossed!

Riveting... first experience(s)

All the corrosion proofing is done!  Not my favourite job, but needs to be done - and done right.  I am quite happy with the results so far.

First step was to rivet the forward and rear spars together, along with the root and counterweight ribs.

All of these were set with a hand squeezer.  Only had one crooked that had to be drilled out and redone.

Trailing edge of the rudder skins epoxied per one of the tips in the manual.  It yielded a perfectly straight trailing edge, that looks quite good.

Skins temporarily fit on the framework to again check for straightness.  All looks good.  Lines up perfectly on the jig.

Some friends that have vast amounts of experience riveting a number of aircraft projects gave me a hand for the day to teach me the finer points.  I learned a lot in 4 hours of watching and questions.

We riveted both sides of the aft spar, and half of the forward spar.  As I am in Canada, we cannot close up any structure until the 'pre-cover' inspection is complete.  So only half the skin will be riveted for now.  The entire forward skin can be riveted, but the tip rib will need to be left off so the inspector can see down into the spars.  Also need to install the counterweight.

Not a bad days work.  

Next:

- Install counterweight

- Rivet forward skins

- Rivet one skin to the root rib

Then it will be onto the horizontal stabilizer!

Rudder drilled and fitted. Time for corrosion proofing!

Happy New Year!

Sometimes it feels like this project is just screaming along, and then sometimes... not.

In the later part of last week I finished fitting the skins including the forward skin and root rib, and making the counterweight.  So now it is on to corrosion proofing.

The manual says to corrosion proof everything, and at a minimum Alodine all surfaces.  After talking to some experienced builders, I decided to Alodine all surfaces - both inside and out, which means all the plastic had to come off the skins, which was a bit of a job in and of itself.  But it only took an afternoon to Alodine the entire rudder, and prime everything.

So with everything Alodined and primed it time to start assembly.  I ordered a Redbox 737 Rivet gun from Aircraft Spruce, but it isn't here yet.  My rivet squeezer is backordered as well, so I borrowed a squeezer so I could at least start.

Root rib to the aft spar was the first order of business.  Had to make some little gauges for determining appropriate rivet length, as well as the shop head dimensions post riveting.  

If you have these, it makes choosing the right length of rivet a no brainer.  The amount of tail sticking through the surfaces to be riveted needs to be at least 1.5 times the diameter of the shaft.  I saw an article in sport aviation talking about making these little tools, and thought nothing of it.  Now I get it!  I really should stamp the numbers instead of sharpie as they will disappear in short order.

I then realized that I had countersunk the wrong side of the hinge bracket, so had to make a new one.  Then Alodine and prime... so while I was waiting for that to dry I JB welded the trailing edge of the skins together.

Aft spar and root rib riveted together.

Once the primer is dry I can start riveting again.  But I think I will run out of things I can rivet without the gun pretty quickly.  We will see...

So far I haven't hit anything insurmountable.  But this is only the rudder, which is the easiest of all the parts to assemble.  The wings are on order (standard build kit) and will ship around April 4th.  So my goal is to have the rudder, horizontal stabilizer, elevator, and trim tabs all done by then.  That gives me 3 full months (minus spring break vacation with the kids).  I think / hope that is doable!