The second assembly I completed was the horizontal stabilizer. This follows a similar process as the vertical stabilizer, except it is larger, there are two skins, and the front spar requires some trimming and bending.
Initial assembly of the rear spar. Here the center hinge bracket and bearing can be seen already riveted, which will eventually attach to the elevators.
I made my first major mistake when working on one of the front spars. After trimming the flange, bending, and creating the relief notch, I was sanding the edges and accidentally knocked the surface of the part into the belt sander leaving a large gash. This is an important structural part, and I would need to order a replacement spar from Vans.
Mistake on one of the front spars of the horizontal stablizer
Eventually I recieved the replacement part and was able to continue. After preparing and priming the parts, I began riveting the skeleton.
Riveting front spar to rib
Preparing to rivet rear spar to rear spar reinforcement bars
Completed riveting rear spar
Other side side rear spar after riveting. Here the “manufactured” heads of the rivets are visible.
Close up of riveting of inner hinge bracket to rear spar
At the begining of 2023, Vans released a service bulletin for the RV-7 outboard elevator hinges due to possible cracking in this area. New parts were designed and sent out to me including a nested spar doubler. Luckily, because of my slow building speed, I did not need to remove any rivets to install the new parts:
Close up of riveting of outboard hinge bracket to rear spar.
Completed rear spar
Next, I riveted the front spars together with spar doublers and reinforcement angles. The cleco clamps with masking tape were to remind me to not rivet these holes. This is where the horizontal stabilizer will eventually attach to the fuselage.
Riveting front spars Riveting front spars
The two rivets joining the the inboard forward ribs were particular tricky. Unfortunately I didn’t properly set the rivets on the left side and need to remove them. Furthermore, when I removed them, I realized the holes were now slightly oversized. After consulting with Vans support, their recommendation was to use Cherrymax oversize universal head rivets in place of the solid rivets. I picked these up from Aircraft Spruce. I cleaned up the holes to the proper diameter for the Cherrymax oversize rivets and was able to set them without further issue.
Oversize Cherrymax rivets set to fix my mistake on two nose rib rivets on left side of photo
Finally, it is time to rivet the skins onto the horizontal stabilizer structure.
Starting to rivet skins onto structure, starting with the nose rib, as specified in the instructions
Next the nose rib was blind riveted to the rest of the completed structure.
Nose rib blind rivets inside the skins
The skin was clamped into place and I proceed to rivet the rest of the skin to the structure.
Skin in place on left side of horizontal stabilizer
Top of left skin riveted Close up of skin rivets sitting flush inside skin dimples
The rest of the skin was also riveted.
Me riveting the skin
The only thing that remains is to squeeze rivets on the inboard and outboard ribs, and on the rear spar, which I will do at a later date after my work is inspected by an EAA tech counselor. Once the rear spar is riveted, it becomes difficult to inspect indside the structure.
Horizontal stabilizer mostly completed