Building, testing and operating an experimental aircraft

Vertical Stab Complete

19 Apr 2010

Dad and I put in several hours in the shop yesterday, and a full day today, to finish off the vertical stab. After the primer had dried and we touched up the parts that needed it, we began by mounting the Cleaveland squeezer to the bench and setting the big AD4 rivets in the rear spar.

VS Rear Spar Squeezing VS Rear Spar Squeezing

We’d had great luck with the bench-mounted squeezer while riveting the HS rear spar, and this time was no different. Everything turned out great, including the countersunk AN426’s near the base of the spar. Having the unwieldy squeezer affixed firmly to the bench makes a big difference in the finished product.

VS Rear Spar VS Rear Spar

We’ve also gotten fairly adept at riveting with the Sioux 3X gun and tungsten bucking bar, although we seem to have type-cast ourselves a bit. Dad’s been doing all the shooting and I’ve been doing the bucking. We’ll have to learn to switch up sometime soon, but we’ve really got a good rhythm down so far.

The Robot The Robot

Ah, “The Robot” – a Christmas gift from my sister to Dad – has made all of our riveting success possible. This little oddball from Mars has illuminated the inky depths of our shop head ignorance with its eerie blue LED light since the very beginning. It has become virtually indispensable. I highly recommend picking one up next time you’re in that neck of the solar system.

Shop Heads Shop Heads

We’ve had a bit of bad luck when using the Cleaveland squeezer free-hand (more on that later), so we used the rivet gun and bucking bar for the remainder of the riveting. You’ll notice the duct tape on the bucking bar – it helps to pad the sharp corners and keep them from scratching the primer while the bar is “bucking” on the shop head of the rivet.

Closing the VS Closing the VS

After getting the forward spar and ribs together, we clecoed on the skin and started tacking it down from the center outwards. Once again, “The Robot” came in handy for inspecting the shop heads deep inside the assembly.

Bucking with the Robot Bucking with the Robot

Once we were done reaching inside the stab to buck, we clecoed on the rear spar assembly and began riveting around the edge of the skin. Although we could have reached most of these with the squeezer, we kept up the gun and bucking show, with good results.

Rivetheads: Brian and Dad Rivetheads: Brian and Dad

There were a couple of rivet placements – the leading edge of the stab and near the big rudder hinge bracket – that we couldn’t reach with squeezers or the bucking bar, so I went ahead and ordered a 4-inch “no-hole” yoke from Avery. Hopefully that will aid in accessing those tight spots.

Other than that, however, the vertical stab is done. Bwahhaaa! On the the rudder!

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