Moving right along, now that we have the horizontal stabilizer in place (make sure the epoxy is completely cured before moving on. Letting sit overnight is a great idea) we can move on to the vertical stabilizer (sometimes this is referred to as the “fin”). I've read that some people will add tri-stock to the sides of the vertical stabilizer to get a more durable joint. While I understand why some may need to do that, I don't feel that it's needed. If you take some care and get a good epoxy joint you shouldn't need to add extra wood to the joint. Now I'm not saying that you can't do this if you want to, it's just something that I choose not to do.

By now you're probably figuring out that just about everything we do when building calls for a little bit of prep work. This step is no different. Just like with the horizontal stabilizer we need to make sure that the vertical stabilizer sits properly and is straight on the fuselage. Unlike the horizontal stabilizer where it's possible to be out of square with the fuselage, the vertical stabilizer needs to be straight in line with the fuselage. With that in mind let's jump in and get the vertical stabilizer ready to mount.

First off we need to mark the center of the vertical stabilizer. You will want to do this at the rear of the stabilizer (picture #1). It wouldn't hurt to do this at the front of the stabilizer either, even though there is a cutout to mount the front of the stabilizer in. You'll want to do this because in most cases the cutout will be oversize, so it will be hard to correctly position the stabilizer in the cutout unless you mark the centerline. In picture # 2 you can see the original mark that we made when we mounted the horizontal stabilizer, we can use this mark as a reference here too. As I just mentioned it will help us to mark at both the front and rear of the vertical stabilizer. The way that I've done this is to mark where the outside edges of the vertical stabilizer will be on the fuselage (pictures #3 and #4). If haven't already done it you'll need to continue the centerline from the front of the horizontal stabilizer to the rear of it. This will be the reference mark that we will line up the rear of the vertical stabilizer on (picture #5). Before we epoxy the vertical stabilizer in place we need to make a couple more checks to make sure it can be properly positioned. Check to see that the entire bottom of the vertical stabilizer sits flat on the horizontal stabilizer and on the fuselage (picture #6). Remember that the forward part of the vertical stabilizer angles upward along the fuselage, so you'll want to make sure that part of the stabilizer sits flat too. The last check that we need to make is that the vertical stabilizer sits square to the horizontal stabilizer. Use a square to make this check, and try to be as accurate as you can to make sure the vertical stabilizer sits at 90° to the horizontal stabilizer (picture #7).

If any of these things that we just check are out of line take the time now to get them correct. As I said before, having a good straight tail section will help make for a great airplane.


Pictures
1. Mark the center of the vertical stabilizer
2. Mark the center of the fuselage at the forward edge of the horizontal stabilizer
3. It helps to mark where the outside edge of the vertical stabilizer will sit.
4. It helps to mark where the outside edge of the vertical stabilizer will sit.
5. Align the center of the vertical stabilizer with the centerline of the horizontal stabilizer
6. Check that the vertical stabilizer sits flat on the fuselage and horizontal stabilizer
7. The vertical stabilizer should sit at 90° to the horizontal stabilizer


Until next time

Ken