Left Elevator & Trim Tab

Time: 6 Hours

After taking care of some work realated business I was able to get into the hangar after lunch. To start was to rivet the substructure of the left elevator. This job went pretty smooth with the help of the pneumatic squeezer. I did have one rivet get damaged due to the die in the squeezer slipping off the head as I pulled the trigger. So out came the drill and I replaced it without too much trouble.

Once you have the substructure all riveted together its time to slip it into the skin. Before you can do that you need to add a “gum wad size” of RTV silicon at the ends of the stiffeners. This helps with vibration cracks in the future.
You rivet the entire skin except the top flange of the trim tab spar, as you have to wait until you are ready to rivet the hinge with it. So I added some blue tape to remind me to not rivet these holes.I riveted every other hole then removed the cleko’s and finshed the rest.The four outboard most rivets on the trim spar call for MK-319-BS blind rivets, but I was able to get the first two with my 4″ no-hole yoke in the pneumatic squeezer. So just the last two are bling rivets on the top and bottom.
After I finished riveting the skin I did a once over to check all my work and found that the last rivet on the inboard bottom had swelled between the skin and rib. This is due to the flange and skin not being tight together and allowing the rivet to swell in between as well as under the flange. So I drilled it out and figured it was due to me not being able to get a good squeeze on it. So I admitted defeat and used a blind rive as it will never be seen once painted.All finished except for the trim tab.Next up was to bend the trailing edge of the trim tab. So I brought out the wood brake that I built. It took just a few pushes on the brake and the bend was complete.As I discussed before my plan was to avoid the bending of the ends of the trim tab. I bought a couple extra ribs to cut up and make riblets for each end of the trim tab. I decided to take on the longer side first as it would have to be cut on an angle.I had to cut a relief into the top of the riblet to be able to sit inside of the tab spar.Next up was the smaller side which had a straight cut and the same relief detail.Once I was satisfied with the fit and how they turned out I broke out the dremal and cutting wheel.Here is the fit after the trim tab ears were trimmed off and the riblets were touched up. I matched drilled both ends and found only one error on my part. The bottom of the trim tab has two horns that are riveted to the tab and make for an attach point for the electric trim. One hole was off by 1/16″ causing a figure eight shape. So I will treat that hole as a normal hole and add another rivet next to it. This piece only has 2 rivets in it normally so I will have a little extra with three.

Next up will be to tackle the trim tab hinge. This is a little bit of a bear to make sure everything lines up and you maintain good gaps. I was in the hangar for 6 hours and figured I was a little tired and this was a good place to call it a night.