<May 9, 2007>

Drilled Left Flap Hinge

I finally got my hinges! I called Aircraft Spruce on Monday, and they apologized up and down for the inconvienience and shipped a new piece of hinge out that day. The theory is that the original hinge that was supposed to be shipped via FedEx, was picked up by UPS, but nobody knows for sure. I was really impressed with Aircraft Spruce's attitude towards customer service. Everyone I talked to was super friendly, they took full responsibility for the delay, apologized over and over again, but most importantly they treated me with respect and took care of the issue quickly. Even if it turns out the fault was theirs, they did everything they could to make it right and showed me that they value me as a customer.

On a related note, now I understand why the hinge cost so much to ship. The box was very well constructed, and to prevent the hinge from getting damaged, it was secured to a piece of wood inside the box.

Anyway, enough about that, back to building. As the page description says, I drilled the left flap to the wing tonight. Overall this was a fairly easy task, but I took my time to get the alignment right.



Here you can see the difference between the -3 and -4 hinges, with the -4 being 1/4" wider overall (1/8" each side). I probably could have gotten away with using the -3, but I didn't want to chance any issues down the road. I didn't bother to draw a line down the -4 hinge simply because I knew I wasn't going to have any edge-distance issues now.

Once the hinge and pin was installed, I clamped the hinge to the wing (skin and flap brace) using small c-clamps at each end. It took a few minutes to get the inboard end or the skin skin and flap braces aligned, but once they were I clamped them tight.

Once I had the flap clamped into place, I verified the alignment by taking a reading of the angle of the aileron and flap trailing edges with my digital level. Both were 0.7 degrees. The actual angle didn't matter (the floor is sloped for drainage), they just both needed to be equal.

I double-checked, triple-checked and quadruple-checked the alignment before drilling the first hole. I really don't think I could have gotten it any better.

I had heard of people having a hard time getting the skin and flap brace to align correctly for drilling, but I had no problems whatsoever. I think the clamps somewhat forced the dimple in the skin into the countersunk hole in the brace, assisting with the alignment at the ends, however because there was no way to clamp the entire length of hinge, there was a series of holes in the center of the flap that where the skin and flap brace were just a bit out of alignment, but it proved to be a non-issue.

I took my time with the drilling, using very light pressure, working from outboard in, inserting a cleco in every hole. As I worked my way along, the clecos that I inserted really seemed to help with the alignment, and by the time I had made my way to the middle, the small difference in alignment between the skin and flap brace was gone. I think I spent 4X the amount of time perfecting the alignment of everything than I did performing the drilling, but in the end it was worth it.