These are those things that I found along the way that did not seem obvious to me at first, or that I think I may have found a method to do a certain task. I am sure that there is nothing new here, but these are things that were not known to me, so I am thinking that they may not be known to you either.
Wing Alignment is critical to insure that you have zero twist in the wing. When setting up to do the measurements as called for in the builders manual, it occurred to me that it is equally important for both wings to be the same. Since we start with the inboard rib, however it falls, how are we to know that the measurement on the next wing will be the same. So, I started with where the inboard rib of the Right wing fell. I measured the plumb distance as stated in the manual. I marked that measurement with a line on a stick at the aft spar. Just FYI, it came out to be 2.75″. I then used the same stick, duplicated, on the outboard end, to set zero twist in that wing. I kept those sticks for use on the next wing and set both the inboard and outboard to match the line on those sticks, of course, used on the same relative side of the wing, upper, in my case. Here are some pictures of what I did. The one at the end just shows how I locked the inboard end, so square could still be set without disturbing that setting.
Another thing you must do is to be sure the wing is square. I take this to mean that the ribs are perpendicular to the spar. So, to make it easy to keep a check on this, I used cleco clamps to clamp a square to the main spar right on the edge of one of the center ribs. Now, I can move the spar inboard and outboard till the rib lines up perfectly. I left the square in place till I had one side of the skins in place and knew it could not get out of square.
Sometimes after drilling and removing the skin for de-burr, it can be a bit difficult to find the rib in some of the holes. I found that an awl worked perfectly for this.
Support for the .060 hinge spacer. You need a backing plate for the .060 spacers that you will use to offset the hinge from the surface of the aileron or flap. This should also work for other control surfaces that require the hinge be offset. I think that is all of them. I wish I had known this method when I was building my tail. I rivet my control together, leaving out enough holes to cleco on the backing plates.
I wish I had a tip for you on how to get a perfect cut on your hinges, the first time. But that is impossible for me to do because I screwed up every one of my hinges at least once. I lost track of how many more hinges I had to order.
There was some discussion over concern about the hinge curling up when dimpling. I found that this prevented that. However, even if they curl up, it is not a problem to install them. I simply dimpled the hinge when it was pinned to the half installed on the control.
- Posts in the Tips Category
- Upside Down Drill Press 2017/11/12