September 29th , 2007
Left Elevator Trim Tab Construction
The left elevator for the most part went together like the right side. I was having a hard time squeezing the AN470AD4-5 rivets with my squeezer. I don't know if the colder weather made them hard to squeeze or what. Anyhoo, I ended up banging them out with the rivet gun.
The counterweight gets loosely attached to the skin and then the whole spar/rib assembly is inserted into the skin. One thing to note in this picture is I dimpled the front part of the rib behind the counterweight. I don't know why I did this but it is not needed. Duh!
The same two rivets on each side of the E-713 get riveted in place before anything else. This is because you cannot reach them once the entire rib/spar assembly gets put in place. Make sure you put them in the right holes.
Now before the skin gets riveted, I managed to squeeze a blob of clear RTV at the trailing edge of every stiffener.
I made sure to mark the top of the skins where the trim tab hinge gets attached. The "No's" will remind me not to rivet these holes.
Okay, the skins are clecoed in place. Time to start riveting!
Here is a shot after I was done riveting both sides of the skin in place.
The next thing I tackled was to bend the skins at the end where the trim tab is. The first step was to mark a perpendicular line on the top and bottom. The bottom tab gets bent up and the the top tab bends down over it. This will help keep liquids out of the gap from the top side.
I needed to make a block to put between the skins to give them something solid to bend against. I cut this out of some scrap wood I had laying around. I folded some duct tape on top to work like double sided tape. It worked pretty good.
The next thing was to clamp it all in place. A lot of guys clamp the trailing edge down to the workbench. I initially did this but I substituted a piece of wood in there so I could move the whole thing around while I worked. I then used a piece of wood to bend the "top" tab down (It's really the bottom tab upside down). This required a little finesse.
A quick pass with the rivet gun made the bend almost a perfect rounded 90 degrees. I use masking tape on the flush set when riveting to help with the scratches. After this was done, I re-clamped everything again and did the other side.
The completed product. I am happy with how this turned out.
The next thing I did was rivet the trailing edge spar in place and secure the inboard portion with blind rivets.
I drilled out two #30 holes in the side where the pop rivets go.
The plans call for two, but I added a third rivet to help keep the last portion of trim tab down.
Trim Tab Construction
Now was the time to start the trim tab. I was kind of dreading this part of the process but I was relieved to be working on something other than those elevators! The instructions are somewhat vague when it comes to the trim tab. This may be why so many builders have problems here. Van's leaves a lot up to the builder on fitting it together. The first thing I did was mark the bend lines. Here is the right side.
And left side...
I constructed a block as described in the manual to hold the trim tab while the ends are bended.
Here it is clamped in place and ready to bend using a block of wood the same way as the elevator tabs.
After the rivet gun is used, the bend is very crisp.
Here is a shot from the side. The top of the bend looks a little rounded in this picture but in reality it is very crisp.
Using a straight edge I checked to make sure the bend was in line with the edges of the trim tab. Perfect. I am calling it a night here.