HP-24 Project

Update 11 June 2003: I hate compound curves

The horizontal stabilizer plug is all assembled, and I've just been sanding on it to smooth it out. I've been averaging about 12 hour per week, putting on filler and sanding most of it off again. I'm getting pretty good at that bodywork kind of stuff, but I'm not having any much fun with it.

It's more than a little bit disenheartening that 90% of my time is being spent working on about 10% of the area. And that area is the compound-curved tips that I so blithely drew into my three-views. It was a pain making the tips, and it's a pain bringing them to contour, and it's a pain sanding them smooth.

If I'd just drawn squared-off tips and called it a day, then I'd be done by now. The ruled surfaces of the stabilizer have been painless by comparison. It's funny how those little flourishes can cause so much grief.

Earlier this week I submitted sketches for CNC hotwired foam cores for more of the tail stuff. Namely, the vertical stabilizer, the rudder, and the aft 77 inches of the tailboom. I'm waiting for the foam core guy to call me back so I can give the go-ahead.

There was one design change that creeped in over the weekend. I stretched the vertical fin by 2". That change has nothing to do with aerodynamics or stability, though. What happened was that I realized that the original fin didn't have enough span for me to fit a 1/2-wave dipole antenna inside.

One odd point of attention at this point is the mounting provision for a pneumatic tailwheel. I'll probably go with the 210x65 pneumatic tailwheel found on the Libelle and many other similar gliders. However, I can't seem to find specs for diameters and widths, or any commercial suppliers for the hubs. Like the tow hitch, I'll probably end up buying a used one from one of the glider repair shops and measuring it. Anyhow, the tailwheel mounting provision will probably be a separate one-piece molding that incorporates the fairing, the internal fender, and the axle supports. I sort of thought that, given all the pneumatic tailwheel conversions I've seen on ASW-20 and similar, someone around here would have developed one that I could adapt. If anybody knows where to get such a thing, I'd appreciate it if you'd let me know.

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page updated 11 June 2003 all text and graphics copyright (c) 2003 HP Aircraft, LLC