HS finished

So, there it is, the new HS. Have to trim the tips to correct span and probably adjust the overhang slightly. The "thread check" on the hinge brackets now shows a straight line, so the elevator will work this time.

I actually have 6 (six!) ruined HS skins in storage now :-) The two first where wrong due to HS-406 ribs is not made by Van's according to the plans, I found that out the hard way, and Van's sent me new skins free of charge. The next two were bent wrong by Van's, I found that out the easy way by measuring them, and again Van's sent me new ones free of charge. But due to the jig bending, the hinge brackets were out of line. The last two I purchased along with new ribs and spars. They were bent correct within my measuring accuracy.

Someone at EAA said something like "It is never skill or workmanship that finishes an airplane, it is the will to do so". He was absolutely correct. I know that at this time both my skills and workmanship are more than good enough to finish this airplane, but all the problems with the HS has degraded my will to finish it for long periods of time. I have to remember this - always, and keep on building.

HS skeleton riveted together

Riveted together the HS skeleton and placed it in the jig.

HS skeleton

Started mounting the skeleton.

Riveted front spar

Riveted the front spar on the HS. Started on the ribs.

Aft spar finished

Adjusted HS skeleton

Adjusted the HS skeleton in the jig. Started positioning the skin.

Inspected holes in HS

Due to riveting the skin, taking it off, then on and off... some of the holes are now a bit too large, and a fair amount of oops rivets need to be inserted. I would prefer not to, but at this stage it is better to move on. When I'm finished with the plane, and I'm still not satisfied with the HS, I will have lots of time making a new one. Priority now is that the HS is straight and strong.

Skin off HS

Took off the skin from the HS - again.

Quick fix on HS - no luck

Riveted a few of the rivets on the aft spar. Then I took off the HS from the jig too see how things were going. As I suspected, what had happened was that even though the HS was straight in the jig, when it came off, it took the former shape. Each single cleco doesn't really force the HS into shape, but all of them together does. The rivets will also force it more into the former shape, because they naturally will center the holes when they are squized. So when in the jig, the HS was in a lot of tension that increased a tiny bit for every rivet that was squized. When taken out, the tension is released, and the HS gets to its former shape.

So much for easy fixing. There is only one way to fix this: New skins.

Riveting HS

Rivted on two of the ribs. Ordered more rivets from Aircraft Spruce.

Riveting HS skin

Finished riveting the center spar to the skin.

HS and skins

After the jig was straightened, I tried to put the old skins on, to see if how far off they were. For some odd reason they fitted. Some rivets are a bit tight on the aft spar near the tip, but not by much. I guess the flexibility and the diameter of the holes compared to the rivets allows for large variations for pieces of the size of the HS, hence the importance of jigs (straight jigs that is).

Contacted Vans about this, and according to Ken Scott: "I would try riveting the stab back together, with it held in the jig. Variations this small can be taken out just by re-riveting". So the fix is hopefully much easier than first anticipated.

HS in the jig

Reconfigured the jig for the HS again. Added one adjustable support in the middle to keep it straight. Inserted a line through some additional holes in the temporary hinge brackets to see if the jig is straight through the process, and to be able to adjust if necessary.

Deskinning the HS

Started deskinning. It was easier than I though. One side takes about 1 1/2 hour. Listening to "Bailando" on my boob radio via the FM sender on my N900 also help :-)

Rudder and VS and the unpleasent truth

The vertical stabilizer and rudder is finished. I washed off the excess zinc chromate with acetone, leaving only zinc chromate at the mating surfaces. I guess a very practical feature with single component primers is that they easely can be washed off, and that is also a bad thing. Single component is nowhere near as tough as epoxy based primers. The rod end bearings must be adjusted, but this job requires two persons. With the VS and rudder finished it is definitely going forward.

But things are also going backward. During the time the HS was in the jig, the wood in the jig changed shape, probably due to changes in temp and moisture with changing seasons. The result is that the hinges on the HS do not line up. The error is approximately 5 mm. To get it right I would have to shim each tip hinge bracket approximately 5 mm out. This is a lot. It will not look good, and it will also mean more forces on the HS spar. I have a set of usable skins, and have decided to replace the skins on the HS. Just to take them off without damaging the skeleton, will take a lot of time. This will be the third time I fit the skin on the HS, and the third pair of skins.