SOME RATHER IMPRESSIVE progress in the rocket-fuel department. Cool.

UPDATE: Reader Doug Pratt emails:

Thanks for the posting about hybrid rocket motors. You’re right, it’s cool. In fact, we rocket hobbyists have been flying hybrids for the past seven years! They are great fun, and since none of the components are explosive, we don’t need any special licensing or storage for the motors.

We use nitrous oxide as the oxidizer, and plastic pipe of some sort as the fuel grain: PVC, polypropylene, or cast thermoplastic of some sort. There are several commercially available systems.

I’m proud to say that I designed the ground support equipment that controlled the filling and firing of the nitrous oxide hybrid motor in the article you linked to. My company specializes in unusual products and accessories for model fliers. I got interested in hybrids several years ago, and my modular launch system has gone down quite well. You can see the catalog at PrattHobbies.com. I also set up a web site last year to disseminate information on hybrid motors in a sales-pitch-free environment; that’s at FlyHybrids.org. Anyone who is interested in learning more can start there or at FlyRockets.com, which is more of an overview of the entire sport.

Like a lot of amateur activities, model rocketry — at its high end, at least — is likely to be a source of considerable innovation that will spread into military and commercial applications. That’s one reason why I think it should be encouraged.