When life happens it's not always convenient. I've been away from this blog due to some unforeseen unpleasantness in my continued employment, or sudden lack thereof.
Fortunately for me, my layoff didn't take. I've been hired by another company whose forward thinking and innovation have proven very successful in a similar market. I couldn't be happier. Yea!
So I've been working on fitting the wing tips. The tips are a fiberglass affair that must be trimmed to fit. But the first thing to do is to fix the aileron in the neutral position as seen in the previous post. Only this time, the jig must be removed so that the wing tip can be fitted. After a few unsuccessful Rube Goldberg-esque attempts, I finally just made wooden clamp shown below. It's just a piece of oak with a hole drilled through for the aileron push tube. Screws in the top provide the clamping force and screws in the front fix the clamp the the inboard rib.
The clamp is tightened while the neutral position jig is still on the outboard wing rib and aileron is held in place nicely.
The next thing I noticed is that the wing tip had a bulge along its outside edge. Using a laser line generator (leveling device) I could determine the location and amount to trim over the compound curvature.
It's a bit messy while triming, but once its done... Well once it's done, you find out it doesn't fit. My tips were off along three different planes. First, the back edge of the tip is supposed to align with the trailing edge of the aileron. My tips were longer than the aileron. They were also lower than the neutrally positioned aileron by about an inch. And finally, the trailing edge of the tip was not in parallel to the trailing edge of the aileron.
I don't know what else could have been wrong with these tips. I'm not at all certain that they were made for an RV-7. Oh Well. Using the laser again I was able to force the trailing edge of the tip to get in line with the aileron. I positioned the laser line on the trailing edge of the aileron and then taped a block of wood to the tip to catch the line. Adjusting the tip until it was parallel to the aileron and then match drilling the inside tip edge to the wing fixes the tip in position.
But the tip edge is still not an inch off of the aileron. This is where the cut-off saw makes another appearance. The whole trailing edge and half of the outside edge are split to allow the tip to be moved up.
Once the tips are trimmed and split, they must be epoxied back together. Only this time, unlike when they were originally manufactured, the trailing edge curvature matches that of the wing and aileron.
While I had the epoxy out, I laid up a couple of strips along the inside seam to offset the fiberglass that was sanded off while straightening out the outside edges.
With the epoxy cured the tip stiffening rib is riveted in place. It's only clecoed in the photo above. The final step is to rivet on the 38 nutplates the will finish the attachment of the wing tip. One tip down and one to go.
Although the tip is fitted, there is still a fair amount of finish work to be done before it will be ready for paint. The re-glued seams for example, will require significant attention.
And now the good news: My fuselage kit has been ordered and is scheduled to ship in the first week of April.
No comments:
Post a Comment