Right outer wing surface

Started on the ribs for the outer wing surfaces. The second ribs require a 19 reamer and a 20 drill bit due to the AN365 bolts/screws used as fasteners. Luckily I had those from earlier.

Stacking the main spar

Started stacking up the main wing spar. I definitely need some more and longer sheet holders. Even the 1/2 inch is too small. I have to order these, and leave the main spar for the time being after I have deburred the edges etc. 

Aft outer spars and main inner spar

Finished outer aft spars. Started on main inner spar.

The other outer spar

There was too few 470 5-9 rivets. If it is an error from Sonex or if ACS has put a finger on the scale I don't know. Luckily I have a rivet cutter so I took a few 5-16 rivets and cut them to correct size.

Outer wing spar

Riveted the outer wing spar.

The other one is primed and left to dry overnight. Started with the aft spars. Deburred and bent the flange to correct angle.

Left outer spar updrilled

Updrilled the right outer spar

Rather straight forward, but I wish I had the Drill Doctor when I reached the steel. I hope I stacked them right though.

Stacking of outer spars

Finished with dimpling and priming the mating surfaces of the vertical tail. Can't rivet the skin before Lasse has been here. Started stacking up the main outer wing spars just to understand how it is going to be. I wonder if I got enough long clecos to do this. Also the main webs was very water stained, probably during transport or storage at Sonex (Indoor in Norway the humidity is way too low for any water staining). Water staining is the most common kind of crevice corrosion in aluminium. Water staining will make the aluminium even more corrosion resistance, but it also makes it harder to get coating to stick.

Ordered a bunch of CherryMax rivets for the ribs on the Horizontal tail, the spar and aft rivets will be solid. There really is a huge difference in diameter of the holes that are drilled with #30, deburred the "old way" and dimpled and the ones that are drilled with #31, deburred the correct way and dimpled with the "tuned" dimple dye. Dimpling is a much more straight forward process when using solid rivets.

Also ordered i Christmas gift from my wife, a Drill Doctor 500X from ACS Germany. It seems to me this 6061 T6 is much harder on the drill bits than 2024 T3. When I get this Drill Doctor I will always have super-sharp drill bits which is the most important thing regarding hole quality and to minimize burrs. The 500X will sharpen anything, high-speed steel, cobalt and TiN.

up-drilled the vertical tail

When the electricity came back after the hurricane Ivar had come and gone I updrilled the vertical tail using 31 drill bit (and 30 for the tip).

Vertical tail skin and tips

Pilot drilled the hinge and the rest of the skin and tip. The skin was still too tight around the tip, so I trimmed the skin a bit. Still it was too tight, so I had to trim the tip as well. This time I only trimmed it so a thin fibre glass was left. After I reinforced it on the inside with two layers of glass cloth and epoxy.

Vertical stab tip

Drilled pilot holes for the fiber glass tip. Filing the inside front and trying to push it as far back as possible should allow it to fit without having to cut it up in the front.

Flaps and vertical tail

Finished the flaps and riveted/bolted the vertical tail.

Found out how to achieve correct holes so the CCC-42 rivet stems don't get pulled through. First I filed my 120 degree dimple die (used in a C or squeezer) a bit more so that the male end enters fully a hole drilled with a #31 drill bit with no friction or without having to use any force. Then I revisited what is actually said about deburring of holes that is to be riveted. In the book "Standard Aircraft Handbook" by Larry Reitmayer it says that burrs under either side of the rivet is no concern, but should be removed if the sheet is not to be used immediately to not cause scratching when stored or injury to personnel. Drill chips between sheets should be removed. Removal of any "appreciable" amount of material from the edge of the rivet hole should not be done. Although I have not removed any appreciable amount, I have used a normal rotating deburring tool. So, with the trimmed dimple and deburring with a glove, a perfect rivet with a #31 dimpled hole.

Since Lasse has not yet shown up, I have yet to rivet the skin on the horizontal stab. The h-stab has #30 deburred and dimpled holes, and none of those rivets will actually fit correctly. I still have the choice to use solid rivets and Cherrymax. I will see.

Flaps

Drilled pilot holes in the flaps and hinges

Rivet binding strength

Spent this evening on investigating different ways of drilling for the countersunk rivets. Some info can be found here and here. The issue is mainly what drill size to use, #32, #31 or #30. I made three samples that I wanted to tear apart in the vice. It all went well until I found out the very hard way that my vice is very good for pushing things together but terrible at pulling things apart :-) (when pulling, the big bolt just comes out not taking the rest with it).

Then I tore them apart using a flat screwdriver and found that the aluminium sheet broke before the rivet fastener. Doing this I mounted them flat standing in the vice, so that one part was in the vice and the other part including the rivets standing on top. I then got the idea of using a hammer sideways, parallel to the surface, to get a torsion (and shear) load around the rivets, that will then be felt as shear on each rivet. So I took what was left of the samples and made new rivet connections. This time I used straight forward 30, 31 and 32 drill bits. I used my squeezer on the 30 and 31 holes and the "simple" pulled dimple die on the 32 hole.

The result was that I had to bang from side to side and totally bend the pieces out of shape to get them apart. The #30 drilled eventually separated because the shop end of the rivet got pulled through the hole. The #31 drilled did the same, but the plate also got torn up. The #32 drilled separated because the sheet broke while the rivet bonding was intact.

So what is the strongest? For all the samples the aluminium plates had to be hammered way past yield strength back and forth several times. The pieces also got bent, which means there was tensile stress in addition to shear stress. So who knows? The #32 sample seems to have the strongest bonding, but it was also the easiest to brake apart, so it could very well already be fractured from the previous abuse with the screwdriver. Besides, #32 holes are totally impractical because a 1/8 cleco won't fit and the 3/32 cleco is too loose. The only possible way is to match drill to #40 or slightly larger, then un-cleco, drill up to #32 and dimple in one go because the 1/8 clecos fits the 32 holes after dimpling. Using solid rivets is also an option of course, they are not nearly this sensitive regarding exact hole size.

All in all, when the pure pull test didn't work out, I didn't really get that much more knowledge other than knowing that the rivets are not likely to pop out of the aircraft unless the aircraft is bent and twisted beyond recognition, no matter what drill size is used. However, the ball on the stem is never pulled through when using #32 drill bits for whatever that is worth.


Also tried to polish the Topgloss BR with Biltema rubbing by hand. The result was surprisingly good. Really nice and shiny and smooth.

I then tried to polish it with Jotun Hardwax and also some old car polish I had laying around, but then it got all milky. The tech sheet says that polishing the Topgloss BR may cause milkyness, but not Hardwax, the tech sheet is obviously wrong.

If I can rub/polish this polysiloxane paint this easily, I probably also can roll on some polyurethane just as easily and hopefully be able to polish it without getting this milkyness. I begin to suspect that this polysiloxane Topgloss BR has been rushed out into the market before it is fully usable.

Right aileron

Left aileron

Finished riveting the left aileron. The led was cut according to the plans. The plans suggests that the led is over sized and need to be trimmed. My led on the left aileron needs to be enlarged, and this is with no paint on! Still have not decided paint or no paint, so fine trimming of the led counterweight have to wait in any case.

Aileron and flaps

Trimmed and drilled the led counterweights. The led sounds easy to work with, but is actually very laborious and difficult. Destroyed two drill bits and I hope my vixen file is still OK. Deburred, dimpled and primed the ailerons, but the primer was still a bit moist here and there, so I let it cure overnight.

Started with the flaps, the last moving surface. Cut to correct shape and measured up the position for the ribs.