Rivet count: 303
Garage Temp: 28-40F
I just got back from a business trip, my daugher is back from college for Spring break. and we’re having a contractor in to look at some house upgrades, so it was a busy weekend. I had to make some deposits in the bank of family harmony rather than spend the weekend in the shop. I did manage to get two half days in however (thanks Honey!)/
This weekend was all about assembling the vstab. Everything was pretty much ready last week except some countersinking and dimpling on the rear spar doubler. On Saturday, I dove right in. First step, countersink the big spar doubler…
I used one of my countersink cages. It took a few tries to get the depth right. I started with a test hole in a piece of angle left over from the EAA workshop. Even with the cage, you still have to be careful. You have to keep the cage perpendicular to the surface and take care not to push too hard or you end up with an oversized countersink.
The picture is a little blurry, but it shows the countersinks on the forward side of the doubler. The orange tape is to remind me not to countersink that hole (it is used later when the vstab is attached to the fuselage). I countersunk a little deeper than normal because this is a sub-structure, so a dimple in the spar sits in the countersink rather than an rivet head.
With that done, I dimpled the spar and put the pieces back together:
I was able to squeeze all of these with my hand squeezer. The 1/8″ rivets are a bit of work to get going, but they came out rather nice. You have to take care to watch the plans. Most of the rivets are placed with their manufactured heads on the aft side of the spar, but the flush rivets on the bottom of the spar have their manufactured heads forward. The aft ones are done that way so that there is less interference when the skin is riveted on a few steps later.
With that out of the way, it was time to put the framework back together. The plans note (in bold) to be careful with the order. At least one RV14 builder didn’t pay attention and then had to work a lot harder to get his assembled. The idea is to assemble the forward spar and ribs first. Then the skin is added on. Then, the rear spar is added. This can be done with just three pop rivets (for the center rib). Everything else is reachable. Here’s the forward spar and ribs… time to squeeze 8 whole rivets!
Next, the skin goes back on. I was worried that it might be a tight fit after dimpling everything. I needn’t have worried. It all went back together without any real fiddling. I started at the nose with a cleco on each side, then worked my way back along the ribs one side at a time. Take note of the Sanka coffee can. I don’t drink coffee (and most doesn’t come in cans anymore either!). My father-in-law gave me all of his old clecos and the can came along for the ride. I think of him (and the BD-5 he never quite finished) whenever I reach for a cleco!
With the preliminaries done, it was time to get down to business. No more squeezing a couple rivets around a flange or two. No, it was time to break out the tungsten bucking bar and the rivet gun! The bar is very dense and very hard. It makes a really nice surface to set the rivets against. I wrapped the bar in some tape so that it wouldn’t mar the inside rib surface so much.
I put a towel down inside the assembly in case I dropped the bar (as it was sure to leave a mark!). You start at the center rib intersection and then work to the top, then back to the bottom, then to the aft surface. It was a little unnerving. I hadn’t driven any rivets since the class (the back riveting on the forward spar hardly counts!). These were all going to be visible forever! It was a bit hard to see whether they shop head was the right size, but they seemed OK when I got the gauge on them. On Saturday, I finished all the interior rivets and most of the edge rivets (I squeezed most of those). I messed up a rivet in the nose and decided to call it quits for the day (and to get back in time for the contractor who was visiting).
I picked up again Sunday afternoon. First order of business was drilling out the bad rivet. I read a hint about using drill bits meant for plastic. These have really sharp 60 degree tips. It makes it a lot easier to get started with out the drill wandering around. I also used a punch to have a really sure starting point. You can see how nicely it starts! It is a 1/8″ bit so I just use it to get the hole going and then switch to a #40 bit to finish drilling through the head.
Next, you put a pin punch into the hole and break off the rivet head.
Then just punch the rest of the rivet through and you’re done! The blue here is from the Sharpie mark I left on Saturday so I would remember to drill this one out.
The rest of the riveting was time consuming, but mostly uneventful. With the whole assembly riveted together, it felt very strong and it is is extremely light. The rear spar went on pretty quickly. Right after driving the first couple of rivets, I had a terrible thought! Remember the towel I was using inside the skins to keep the skin from denting… I remembered it then too! I peeked through the lightening holes to see if I could spy it, terrified about leaving it rattling around inside there. Then, I noticed that I had put the shop towel off to the side with some other tools. Sigh! Of course it wasn’t in there! I had carefully shaken everything out because I didn’t want any chips or extra dust in there. With that, the vertical stabilizer is done! (Well, until I add the fiberglass tip and farings later on).
To celebrate, I updated the background image to show the vstab in green (done) and the rudder in red (in progress!).
There wasn’t a lot of time left in the day as I needed to head home and cook dinner (turkey legs, mashed potatoes and gravy, zucchini, and strawberries), but I wanted to at least get started. The rudder parts are spread through a number of the part “sub-kits.” The ribs were pretty easy to spot as were the rudder horn and the stiffeners. The trailing edge is manufactured (by you!) from a longer edge (actually a longer part from an RV-10) so it has a label in the initial part diagram, but is not in the inventory. No, the hard parts to find are the small doubler plates (R-606PP, R-608PP, R-609PP). They are not listed in the inventory. They are not in the “miscellaneous” clear plastic bag (where the VS-01401 was hiding). Noooo… the three plates are hiding in a small brown bag labeled “small empennage parts.” One is labeled, the other two have no label (but match the part layout).
The rudder has a surprising number of small parts. Most of them need to be cut apart from larger partially CNC’c parts and then trimmed or smoothed to fine angles to fit inside the trailing edge. I got most of the parts cut out and rough smoothed on my belt sander. It did a great job in quickly grinding off the little tabs left over from the cutting. I did most of the bandsaw cutting by hand, but the stiffeners were a bit intimidating. They need to be cut to a rather fine point. My plan was to run them through the bandsaw to get them close and then use the belt sander to get them properly sized. I remember another builder cleco’d his to a piece of wood and then ran it through the saw. This worked well. All the stiffeners have the same geometry at their point, so I only need two pairs of holes (left and right stiffeners). Then I can work through the block of wood with my fingers safely away from the blade. “We don’t have time for a trip to the emergency room,” my Mom always said!
So, the parts are all found and roughly hewn from their blocks. I still have a lot of deburring and smoothing to do before I get going next time, but at least I have a good start!