Sparcap Bucking Bar (Sept, 27th, 2004)

You may purchase this tool from Sonex Ltd. for a couple bucks (pun intended ;-). However I prefer the hard way. So got a piece of rectangular construction steel of size 50 x 50 m 100mm (2). This dimension makes a nice solid counterweight.

The hard part now is to cut out a wedge-shaped piece to clear the 7 degrees sparcap flange. Of course no sissy powertool is used. Making this 35mm cut took 1/2 hour (and a lot of sweat)...

... and another 1/2 hour of funky ;-) work at the electric grinding stone, at last comes the polishing wheel. All edges nicely rounded so the 'xpensive spar won't be scratched.

The new tool fits (at least it looks so). The arrow shows the rivet location.

The angled rivet set barely clears the 3 degrees flange. Looks as if on this side of the sparcap I can use the 3X gun. Maybe I have to grind a bit off of the 'knee'.

This is the ugly side (seven degrees Flange). It's imposible to place the rivet set perpendicular. Luckily each sehen degree flange is a three drgrees at the opposite side. So I could place the rivets fron the opposite side here.

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Some More from the Mainspar (Sept, 25th, 2004)

Probably the mainspar will accompany me the next several weeks. I'm only building on weekends now. Because I want to avoid bad rivets under all circumstances on the mainspar, setting them takes a lot of time. About two dozen new rivets is all I can accomplish on one weekend.

This 1500g (3 lb) makes a good counterweight. Befier I hit the rivet with my 3X gun I tape the countersunk rivet head with Scotch-tape. This is an old trick of the RV community.

When the spar is properly levelled and the gun precisely perpendicular then the shop heads become very consistent (I get very inconsistent results if I rivet free-handed).

All flush rivets are set except the red encircled ones . These ones are too close to te sparcap - impossible to get by with the gun. Seems I have to bite the bullet and build a specialized sonex rivet squeezer.

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Bolting the Mainspar Together(Sept, 9th, 2004)

There are some AN3 bolts holding the high-stressed inbord end of the mainspar together.

These bolts are hard to insert because the hex-heads barely clear the sparcap. Worse, the bolts should be 'tight fit' so there's no play left.

The boltholes I reamed for precise size.

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Wingbolt-Hole(Sept, 4th, 2004)

I did it! The first wingattach bolthole is drilled.

I spend almost the whole saturday with clamping and leveling. One should regard that even this free-standing heavy drillpress will move when pressure is applied on the drill. So I clamped the drillpresse's table onto the downside of the table. Of course the spars are also clamped tightly to the table. This way the drillpress (almost) can't move while drilling. There was some rattling when drilling through the steel-blocks (remember that my attach-blocks are not of soft 6061-T6 but instead of chromoly steel). These 50mm of steel are much more demanding on the drillbit. I used lots of WD-40 (a good cutting fluid) and slow cutting speed (around 500 rpm).

Sooo the hole is round (good). The hole came out where it was intended to come out (good). Hole is slightly undersize (good). Will it fit? - I don't know. Next steps are: disassembly, final deburring, final assembly, riveting the spars. If we got a mild winter this year then mayby at Christmas time I'll install the spars the first time in the fusalage. And then I will know if this job is successful (of if I have produced a heap of scrap metal worth several thousand Euros).

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Wingbolt-Drill-Kit(Sept, 1st, 2004)

The wingbolts and drill-kit are finally here!

These parts werde made with fine precision by a specialized tooling shop (Kopp-Schleiftechnik GmbH, Winterkasten).

The piloted pilotdrill (1) is US made. I got them for cheap via ebay.

The wing-drillbit (2) makes holes of 9.36mm, the piloted end was specially ground for me.

The reamer (3) is a tapered H7 hand-reamer for 9.6mm final size , also purposely grinded to fit the bolt.

The bolts (4) were actually M10 12.9 high-strength bolts. These are precision ground for roundness to 9.58 mm .

Now the show can begin...

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