Sonex 1404

Posts Tagged ‘SNX-T09

I got the shipment of AN hardware from Wick’s and finished up the vertical stabilizer main (rear) spar. I had to enlarge the holes of the 1/8″ thick spacer because they were not aligned perfectly with the angle bracket, but since that spacer is disposable, I don’t care how big the holes are on it.

I am curious to see how exactly the spacer is useful on this assembly. With it in, the AN3-7 bolts have no thread sticking above the nut after torquing it to about 25 inch-lbs. I checked and re-checked everything just to make sure I didn’t miss anything. Moreover, I don’t know if it is such a good idea to tighten the nuts now and remove them later to remove the spacer plate. I might have to put in new nuts at that point.


I finally got my inch-pound torque wrench from Amazon and decided to finish the spars using the hardware supplied by Sonex with the tail kit. The AN3-7A bolts and nuts went in without a hitch. I measured the run-on torque at between 4 and 8 inch-lbs for each of the nuts.

When I got to the AN3-6A bolts, I added one washer on the side of the nut as called out in the plans and proceeded to tighten them to the required torque. However, the nuts “bottomed out” i.e. reached the end of the thread before it fit snug against the piece. I added another washer and tightened them ( I had gotten to three before I realized what happened) again. The run-on torque had now dropped to between 2 and 6 inch-lbs for the same nuts.

There were enough washers in the kit for two per nut-bolt assembly so I ran out of washers before I could install all the bolts and nuts. I’ve ordered some more from Wicks and have to wait until I get them to finish up the aft-spar.


I’m chugging along with making all the parts. Cutting the rudder skin turned out to be a non-event this time. I measured it three, four, five times before cutting it. I used the bandsaw this time which made a world of difference. My previous attempt was with the snips and it was literally a pain. I test fit the rudder drive horn and it looks perfect.

I finished some more of the vertical stabilizer spar channel fabrication along with cutting some of the piano hinges. The channel stock was cut to rough length with my miter saw, and the band saw made easy work of cutting the notches at the ends. It looks like I am finally getting comfortable with the fabrication of channel and angle stock.

This morning I decided to begin assembling the aft spar of the vertical stabilizer. I had all the parts and needed to clamp them together, drill them to size, and cleco them. It went well until I made a stupid mistake. SNX-T12-05 which was a pre-finished kit component slipped a little when I was drilling one of the holes. I caught it in time and drilled the hole again in the correct spot. The problem now is that the hole is too wide on one side, but looks OK on the other. My inclination is to buy another piece and do it again, but I’ve sent an email to Sonex to see if this piece can be salvaged.

A part of this assembly uses AN3 bolts. I looked up the diameter chart and decided to use the 3/16″ drill bit I had. As it turns out, my drill press is very true so the bolts have to be pushed in with considerable effort. I’ve decided to order some #12 drill bits (slightly larger than 3/16″) from Avery and drill out those holes again. Several other builders say this is the right size for the AN3 bolts.

While this is getting resolved, I’ll probably go ahead and start with cutting the elevator skins.