08/15/2018 Horizontal Stabilizer – Riveting Back Spar (2.5 Hours)

I got to work on the project today because of smoke coming from mountain fires forcing me to reschedule the flight lesson with my student. So I finally started riveting the back spars and reinforcement bars.

First I gingerly clecoed them together, worrying I might scratch off any primer if I’m not careful. I soon learned that I would make much much more scratches when riveting so it’s absolutely unnecessary to be that careful when clecoing. When I took the pneumatic squeezer out for the riveting task today I was absolutely confident that there will only be perfect rivets today. I have used the squeezer on practice kits before and it’so easy to use. Well, I was so wrong. The flange of the spar totally screwed me up. When squeezing on practice kits, the rivets are usually the ones at the edge of skin that I can see both the shop head and manufacture head, so I could make sure that the I was squeezing perpendicular to the surface. Now riveting on the spar, the flange blocks my sight that I could only see one side of the rivet. I think the first 3 out of 4 rivets were slanted so badly that I had no choice but drilling them out. It was so bad that I drilled out probably 4 or 5 of the first 10 rivets. The only good thing coming out of this is that I found out AD470 rivets through a thick aluminum bar are actually really easy to be drilled out.

I almost freaked out after seeing my first dozen rivets, so I decided I’m going to try the rivet gun.  I tried one rivet with the gun and it’s even worse than the squeezed ones. In no time I switched back to the squeezer. After some careful observation and trial&errors, I was finally able to set some reasonable looking rivets with the squeezer. After 2 hours of riveting(and drilling out rivets), I finally finished most of rivets on the rear spar, except the ones for aileron hinge brackets.

The first two rivets got drilled out. I forgot to take a photo with the bad rivets before drilling, but you can tell from this photo they were not good.