458.5 hours-Turned center bearing drill guide and trimmed HS tip skins

I rRead some disturbing posts on VAF today that talk about the steps that I am about to perform on my own build. Seems that there is quite a bit of a problem with the elevator trailing edges and counterbalance skins having a bit of a twist or a misalignment problem. I called Vans today because I wanted more information to clarify their instructions which say to place the elevators "in trail" with the HS and then check the alignment of the counterbalance arms with the HS. Many builders interprest this to mean that you clamp the counter balance arms to the HS and that means that the elevator is now "in trail."

Well, I confirmed with Scott at Vans today that the true meaning of the term "in trail" is based on the extended chord line of the HS with that of the elevators. Problem is that it is difficult to determine where the chord line actually is without some reference point, which Vans does not provide in their plans. So most builders use the clamped counterbalance arms as the point where both parts should be "in trail.

Since I still had some excess skin on the HS that captures the counterbalance arms of each elevator and holds them in place, I did not need to clamp anything down just yet. At first glance it looks like everything lines up real nice, but then I got out a long piece of aluminum angle that I know is very straight. I laid it across the left and right elevators along a line that is just forward of the rear trim tab spar on the left elevator. I was shocked at how far off level the angle was. This can unfortunately only mean one thing - that my elevator trailing edges are horribly misaligned, similar to what others have experienced.

Next comes the sad story of how to resolve this problem. The possible solutions range from the following:

1. drilling out the tip rivets, repositioning the counterbalance skins and elevator skins at the tips, drilling new holes for oops rivets, and re-riveting everything.
2. Setting the elevator trailing edges so that thet are even with each other by using a laser level or other device, and leave the offset counterbalance arm "as is." This is the recommended approach.

I won't know how bad everything is until I get the excess skin of the HS tips trimmed away so that the elevators can swing freely. My fear is that the elevators are so badly out of alignment with each other that the control horns will be so badly displaced after aligning the trailing edges that there is no way that I will be able to drill the center bearing holes in each horn without running out of edge distance on at least one of the them.

So I decided to continue moving toward the inevitable by slightly reducing the aluminum drill guide bushing circumferance so it would fit inside the center bearing on the HS. It ends up being a bit too wide to fit inside the center bearing, even though it was advertised as having a 1/4 inch OD, which is supposed to be the same diameter as the bearing. I reduced it to proper size by chucking it in my drill press and turning it against a small piece of emery cloth. I did this several times, trial fitting the bushing inside the center bearing several times until it just slides snuggly through the bearing hole. This worked out fine. Here is the pic of the bushing inside the bearing with the #27 drill bit in position to drill the hole in the control horn when the time comes.

Here is a pic I promised of the clerance between the edges of the HS skin and the counterbalance arm of the elevator - it is about 1/8 inches and is fairly consistent. It also shows the amount of overlap between the forward portion of the counterbalance arm of the elevator and the tip of the HS. This excess skin needs to be trimmed away to allow the elevators to swing freely.

And here are the marks I measured for the cut on the excess HS skin. The plans call for a minimum 1/8 inch gap between the HS and the forward portion of the counterbalance arm. There will also be a 1/8 inch radius on the inside corner, similar to what I did for the removal of the material from the rear spar from the last post.

This time I decided to use the 1/4 inch drill bit to drill the hole without all the upsizing from smaller to larger bits. I started by center punching the mark for the hole, and hand turning the drill bit until the hole was established. Then I ran the drill to finish the hole.

And the finished trim job after cutting out the excess with the dremel cutoff wheel and filing the edges clean with my small file set.

I flipped the HS over and need to reinstall the elevators one more time to mark the cut lines for the other side of the HS. I will finish those tomorrow. Right now I am just sick to my stomache at the thought that these stinking elevators are probably notr aligned very well with each other. If that turns out to be the case I will no longer be a fan of computer aided matched hole concepts and will resign myself to jigging just about every assembly from here on out. Once the excess skins is removed from both sides of the tips of the HS I will be able to clamp the elevators in place, set up my laser level for the trailing edges, and the go throught steps to determine just how far out of whack everything rfeally is. Right now I am expecting somewhere between 1/4" to 1/2" offset, based on the results of my test with the angle laid across both elevators in the supposedly "in trail" position.