The empennage is essentially complete except for the fiberglass tips on the horizontal and vertical stabilizers and on the elevators and rudder. I decided to extend the fiberglass on the elevators to enclose the lead counterweights.
I also glued backing washers on the inside of each hole in the fiberglass to make the rivets more secure.
Time: 6 hours
The difference with the left elevator is the incorporation of the trim tab. The stiffeners are shortened on the inboard side and space is made for the trim tab solenoid motor.
The centering of the motor is important for the linkage to extend to the trim tab without interference. Unfortunately the dimension shown on the plans is in error and must be carefully corrected. A Z bracket supports the motor on the access door which is screwed to the elevator into nutplates. These have to trimmed off to the borders of the access door after riveting to permit the installation of the motor.
The trim tab itself is a challenge as the end tabs need to be bent over each other. A wedge shaped piece of hardwood is inserted in the trim tab skin and the tabs are bent over against the wood. Mine came out pretty good, but not perfect. After assembly the trim tab is mounted to the elevator with a piano hinge which needs to be aligned carefully to permit the trailing edge of the trim tab to coincide with that of the elevator.
Time: 8 hours
The next task is building the elevators. The left and right elevators are different because the left elevator incorporates a trim tab.
I did the right elevator first. The stiffeners are formed and back riveted to the skin. This is difficult for the rivets closest to the crease, but the skin is just temporarily deflected back just enough to set the rivets. The spar and end ribs and the counterbalance rib are assembled together with the counterbalance.
One caution to the wise: The forward spars E-702 are not marked left and right, but they ARE different! You must reserve the spar with the off-center hole towards the bottom for the left elevator. This hole provides clearance for the tail screw of the trim servo, and of course I got it wrong and didn’t discover it until the skin was riveted onto the frame of the right elevator. So I had to drill another hole and put in a reinforcing plate to cover the misplaced extra hole. Vans really should mark the spars as left and right!
The skin now needs to be bent to the final shape. This is done by making a homemade break out of two 2×4 boards united with several hinges. The skin is put between the two boards and a 1/8″ rod is placed in the crease of the skin to provide a minimum diameter to the bend. A lot of pressure is needed to make the bend and it has to be done in several steps.
The skin is then riveted to the spar and rib assembly to complete the elevator.
Time: 6 hours.
February 5, 2017
The rudder is built with two separate skins which are separated by a front spar and united in the rear with a wedge. There is only a bottom and top rib so the rigidity of the rudder depends on a series of stiffeners back riveted to each skin. The stiffeners have to be trimmed, dimpled and the back riveted to the skins.
February 7, 2017
Once this has been completed the skins are assembled with the spars, ribs and the aluminum wedge.
February 8, 2017
I used an aluminum angle screwed to the workbench to provide a straight line for the rear of the rudder. The skins and wedge were drilled through into the angle. Then proseal glue was applied to the wedge and to the skins and the assembly clecoed to the wedge. This was allowed to cure for a couple of days. The result was a perfectly straight rudder.
Time: 15 hours
The rudder skins are joined to form the leading edge by bending them around a 1″ PVC pipe and then pop riveting them together. The pipe is attached to the skin with duct tape and the pipe is twisted with a vise grip wrench to form the curve in the skin.
Time: 4 hours.
After completing the Horizontal Stabilizer the Vertical Stabilizer was incredibly easy and fast. I prepared the spars and ribs, clecoed the skin to them, back drilled the holes, disassembled the parts, sprayed the primer, put them back together and riveted the skins onto the framework. All in less than 24 hours! Now on to the rudder, which promises to be a little more challenging.
Also just got word that my request to the FAA for the reservation of N123LL for my new RV-7A has been granted.
Time: 8 hours
Now things started going faster. First I prepared the rear spar by riveting the reinforcing bars and the hinge brackets to it.
I clecoed and riveted the elevator front spar to the angles and reinforcing plates and the inner ribs.
Now it really got fun, with the first rivets to the skins. First the middle spar was clecoed and riveted to the top skin and then the skin was formed around the rib and clecoed and riveted to the bottom of the rib. Then the front spar assembly was fitted inside the skin and clecoed to the middle front ribs and to the skins.
Then the skin was riveted to the middle rib and front spar with the rivet gun and the tungsten bucking bar. Then the rear spar was slid into place and the skin was riveted to the the inner and outer ribs and to the rear spar assembly.
Now this has really been fun! The first assembly is complete!
Time: 8 hours.
Since I wanted to prime the internal surfaces of the empennage and didn’t have a place to do it, I began to fantasize about the possibility of building a paint booth. One thing led to another and I ended up spending more than a week designing and building the facility. I found a really good electric fan on Craigslist and bought 1 1/4″ PVC tubing, plastic sheeting and filters from Home Depot and used about half of my shop to build a 10′ by 20′ booth.
I inaugurated it by doing the priming for the Horizontal Stabilizer.
I protected myself with a good mask and sprayed all the surfaces with Tempo Zinc Phosphate Primer.
After this paint booth hiatus, things began to move quickly.
Time: 20 hours
Progress continued after disassembly with the deburring and cleaning of all of the parts of the elevator. Then dimpling of all of the ribs and both skins. Used the pneumatic Squeezer for the ribs and the DRDT-2 for the skins. It worked so great for the skins, I’m convinced it might have been better for the ribs as well. The operation is very fast and almost effortless.
Next step is priming. Still not sure if I should prime everything or just the non-alclad parts. My primer is arriving tomorrow: 6 spray cans of Valspar A-702 Primer.
I’m thinking of setting up a paint booth in my shop.
Time: 6 hours
Good progress today! Got to fit the elevator skins on the spars and ribs. It’s amazing how easily the holes line up.
Time: 4 hours
Leonard's RV-7A Build 