HP-24 Project

Update 5 November 2002:

The canopy transparency mold should have been delivered to the transparency shop by today, so we should be getting the first canopy transparency in a matter of days.

Canopy transparencies are generally priced according to their complexity and to how much material they use. So if you've got a simple canopy that can be made with a half of a sheet of material, it costs only a little bit more than half of an equivalent canopy that uses a full sheet. Well, thanks to some judicious preliminary design and a smattering of luck, my canopy transparency is just a fraction of an inch under the threshold between a "full sheet" canopy and a "half sheet" canopy. That means that I've extracted just about the absolute maximum of transparent viewable area from a half sheet, while retaining the half-sheet price. The cost savings is several hundred dollars per transparency, so I'm pretty pleased.

Once we get the first canopy transparency, we'll start work on the molds for the canopy frame. Pretty soon we'll have a cockpit under glass.

On another front, I'm now looking at ways to slice a few months and a few thousand dollars out of the HP-24 program. One very attractive option is to eliminate the intermediate step of my "flying plug" wings, and go straight to molds to make the prototype wings. We'll still need plug wings to make the molds, but we'd save a ton of one-off, throwaway trouble by not making them flight articles. The real issue at hand is that we'd be under pressure to develop a wing/body junction that will work right out of the box.

To recap, the value of the "flying plug" wing approach is that it gives us a shape with which to experiment to find an effective wing/body junction shape. We'd just pile on the microballoons and tuft test it until we get it right. The downside is that to get there we'd have to mess around with a bunch of moldless parts, developing parts and techniques that have absolutely no applicability to the production articles. And all that stuff would just get thrown away at the end of development.

So now I'm looking at several different approaches to get us to representative molded wings as effectively as possible. A couple of them are purely computational, and the others are empirical, using molded wings as the basis for the junction development. Stay tuned while I figure it out.

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page updated 5 November 2002 all text and graphics copyright (c) 2002 HP Aircraft, LLC