To this point the HAPP prototypes have been constructed mostly from plywood, cardboard, tie straps, and hot glue. Plus a few household items you'd find in anyone's well-stocked pantry, such as a 4500 PSI carbon fiber air tank, a couple of Arduinos with inertial navigation chipsets , a pressure transducer, and custom-designed controls software. You know, the absolute basics of the simple life.

Now that we've figured out propulsion and stabilization, it's time to build the flight hardware and finalize all the performance data, especially the inertia tensor and jet force (as a function of gas pressure and altitude). Even after that's accomplished, there's plenty to do - still haven't fully designed the GPS system, satellite downlink for data transfer, or parachute & pyrotechnics - but I want to get the basic structure finished first.

Over the next few posts I'll put up pics and information about the flight hardware build. To whet your appetite, here's a partial list of some of the more adventurous items:

• Carbon fiber internal structure.
• Molded plastic aero shell - which I will attempt to vacuum-mold myself. Which means I'm building a vacuum-molding machine in the "lab" (a.k.a. basement).

Also, I joked in an earlier post about borrowing an altitude chamber for testing the jets in near-vacuum conditions. I've concluded that I actually need to do this. But as this is a 100% roll-your-own adventure, I'm also in the midst of building a vacuum chamber that can hold the old test rig for live fire testing. This is probably the most dangerous part of the project so far (not counting solder iron burns :-) because structural failure of the chamber means violent implosion. We'll see if I get the math right!

It's going to be a fun month. Feel free to ask any questions using the comment section below. In the meantime, here are a few pics to kick off the flight hardware build phase. Enjoy...