HP-24 Project

I'm away from work on vacation this week, and I've been up at the shop working on the horizontal stabilizer parts and tooling. Today looks to be a day off from both, since there's snow down to Douglas Flat and chains required beyond Murphys.

Here's some photos, in chronological order:

The internals jig for the horizontal stabilizer, with shear web backstops positioned and riveted in place.

A closer-up of one of the backstops. I riveted these instead of welding them to minimize distortion of the fixture.

Here's my big project for the week, a fixture to locate the two taper pin sockets on the horizontal stabilizer that mate it with the taper pins that get fixed to the top of the vertical stabilizer.

Front quarter view of fixture. The taper pins are the same units as used on the actual vetical stabilizer. They were made a couple years back by machinist Richard Buege, sometimes known on rec.aviation.soaring as "Lennie the Lurker."

Here I've attached the taper pin sockets and the fiberglass reinforcement that will later get built into the stabilizer shear web.

Preparing to drill the holes for the stabilizer's forward mounting angle. These holes will go through the first-article stabilizer, and also through the mold, which will capture their location for subsequent pulls from the mold. I like getting stuff like this right the first time. The guides I'm using are my working drawings of the stabilizer, with plane-of-symmetry profile, and my working templates.

I've surveyed the part, located the holes, and made centering divots. Note that the foam core and reinforcement pad on this part are a little off-center. No big deal. We'll have better centering of the core parts on the next skin set. It's hard to see, but there are fine pencil marks along the center lines of the black marker lines.

Drilled through 3/16" for the AN3 bolts that will affix the forward mounting angle to the stabilizer. For things like this I often use a 12" drill because it is easier to eyeball it normal to the surface.

Here's a batch of those reinforcing pads that will get built into the shear web at the site where the taper pin sockets will be installed.

Homebuilt aviation is not for folks who don't try things at home.

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