I didn’t have too much time today. The first step was to remove the tail feathers so that I could rivet my new spacers / reinforcement plates. Here’s the end product. 

I put the horizontal stab back on with some clecos and lead shot to hold it in place.   

Today it was time to match drill the front spar of the vertical stabilizer to the angle attachment mounting to the horizontal stabilizer. To do this, you use two strings to the center line of the fuselage and equidistant from the aft portion of the vertical stab. Equal measurements near the front of the stab ensure it is centered. 
  
  

Next, you need to ensure that the vertical stabilizer is true front to aft. The idea hear is to ensure the hinge points for the rudder are in alignment to avoid binding. There are two techniques. First you can use a straight edge provided you have one long enough, or you can use the plumb bob method. I have done the latter. 
  

Once I got the rudder hinges aligned, it was apparent I had another problem. The amount of lift required on the forward part of the stab was going to create edge distance problems for the forward spar. What the heck? Literally two steps ago, Van’s had me trim the front spar length. If I had trimmed a little less, there would have been no problem. Consulting the forums, this appears to be a common problem. So, when you go to trim the front spar, trim less than Van’s calls for. You can always take more off, but its hard to put back.

The solution was to create a new angle. Here you can see the original angle on the left, and the stencil for the new angle on the right.   

Here is the new angle next to the old angle. You can see the old angle is slightly taller, about 3/16″. The original is pre-drilled, whereas my new one was not. To accomplish the match drilling, I made a quick drill template by clamping some scrap to the original and match drilling. Here is the new angle in place with the drill template on top. I needed to double check everything was true both to the centerline and the rudder hinges. Then it was time to drill.

Yesterday I began the installation of the horizontal stab but I ran into an issue with the edge distance on the right longeron. After doing some research, I’ve found that Van’s considers the edge distances here to be “guidelines” and not hard and fast rules. The one solution I’ve seen people implement has been to turn the spacers into reinforcement brackets. The debate as to which edge distances are the most critical here is difficult to determine. Generally, I would default to the longeron being the most critical, but without a proper analysis of this particular joint, its difficult to say. This intersection shouldn’t see much load in sheer, as most load should be applied in tension. Regardless, I’ve decided to err on the side of caution and implement the reinforcement plate.

Here are the templates for the reinforcement plates. Note that the bottom one is not drawn correctly. I failed to connect the dots correctly. Don’t worry, I quickly noticed AFTER I made the cut. Needless to say I had to make a new one. Thankfully my buddy Jack was on hand with spare 1/8″ aluminum. 

Here are the end results. 

I removed the horizontal stabilizer and drilled out the one rivet forward of the horizontal stabilizer’s forward spar intersection, and the two aft. Match drilling these reinforcement plates was going to be a challenge. I began by clamping them firmly in place and match drilling the forward most rivet hole, and the inner most bolt hole.

With these then clecoed in place, I back drilled the remaining holes with Jack and Mike’s help.
  

Here you can see the reinforcement plates after drilling. I feel really good about this intersection now. The edge distances are not that far off, and with this reinforcement, I feel confident in the intersection. I’m further quite convinced that there are other areas that are more likely to fail before this intersection (I’m looking at you SB 14-01-31!)

Drilling the remaining bolt holes was not difficult. I back drilled them from underneath, and everything went perfectly.   

Here is a picture of the problematic right side. You can see that both the edge distances on the angle (orange lines) are within tolerance (and just barely.) However, the edge distance for the longeron is definitely on the short side.   

Here is the other side.

Next it was time to mount the vertical stabilizer. First off, you cleco and clamp everything in place. Then you measure from the top of the stab to a point on the elevator from each side. The point being to make sure the vertical stab is perpendicular to the vertical stab. 

I get 62 & 5/16″ on both sides. 

Camp the forward spar in place lightly. You’ll need to keep the spacer plate aligned. I did this by marking each hole position before installation.

The next portion is confusing. You’ll need to drill the three bolts that connect the tail spring. The problem is, the measurements on the diagram don’t make any sense. The reason they don’t make sense, is that they are flat out incorrect. Apparently Van’s has corrected these schematics since these were made. 

A little digging online, and quick consultation with the plans for Mike’s RV-7 resulted in the measurement shown below. 1 & 23/32″. A great explanation can be found at this kit log site: http://www.mykitlog.com/users/display_log.php?user=jpreou&project=45&category=2153&log=35967&row=212

Drilling these was fairly easy. Use lots of boelube as there is iron on both sides.  

Next its time to drill the two bolts at the top of the rear spar. Note I said TWO bolts, not THREE.
  

At this point it was time to call it quits for the night. I pulled the spacer/ reinforcements off. I wanted to prime them so they could be riveted in place next time.