Over the Christmas holiday we applied the bottom skins to the inboard wing plug sections. Everything went pretty much as well as could be expected.
There was a minor setback when I discovered that the outboard wing plug cores had been fabricated incorrectly. The hotwire guy missed part of the specification that called for a thickness correction to the tip airfoil. He's going to supply a replacement set of the outboard cores, and we'll be right back on track.
I've ordered more fiberglass to use skinning the outboard sections. It turns out that the 50" width is just perfect for the outboards, since the inboard chord plus the outboard chord plus the extra margins equals 48" so I can get two skins per 12' of length. I should have enough resin on hand.
I have more photos besides the ones below, but haven't downloaded them from the camera yet.
This update's photos:
On 27 December, Doug Gray prepares to start saturating the fiberglass cloth in the foreground. In the background is the right inboard wing plug core, bottom surface up. Obscuring the inboard end of the core is the 4 mil poly sheet we use for the vacuum bagging. There's nothing special about this material; we buy it down the street at the hardware store.
The right inboard wing plug about 2 hours later, after we've applied the cloth, bagged it, put the bottom shucks on it, and weighted it down to the table. You can see that we're using heavy steel channels for weights, and distributing the weight over a bunch of fiberboard scraps. There are no intervening photos because we're all either too busy or too gooey to use the camera.
The right inboard wing plug the next morning, after unveiling.
The left inboard wing plug, glassed, bagged, and weighted on 28 December.
The two inboard wing plug sections on 29 December. That's a nice (relatively) smooth 24 feet of wing, ready for sanding and contouring. One of them is twisted about 0.1 degrees from what I'd like, but I've found that they're limber enough in torsion that I can tweak the washout up to about half a degree either way with moderate torque. That's a fortunate result of using a +/- 90 orientation for the fibers in the skins.
page updated 14 January 2004 all text and graphics copyright (c) 2004 HP Aircraft, LLC