The Tri-Mode concept is applicable to everything from amateur rockets to manned spacelift. It uses mechanical (pneumatic launch tube), air breathing (ramjet), and rocket modes, each in their most advantageous (and economical) environment. This application is specific to the amateur rocket community.

Special Notes

• While I am an engineer this site is not being written to replace textbooks on jet engines or ramjets. It’s intended to be a practical how-to for the amateur who can’t or does not want to spend hundreds of hours designing a highly efficient ramjet. For those readers (ex: students) looking for engineering details on ramjets I recommend the older text books and literature, in particular the late 1940s thru 1960s. Newer books tend to avoid ramjets. The NASA NACA site has a great many interesting papers.
• I am a law-abiding citizen of the US (except for speed limits :). If you tell me anything that you are doing that is illegal then I will have to pass it on to the authorities. I also have a day-job that obligates me to report inquiries that appear to come from foreign countries ([email protected] is not a good cover). If I had my way I would consider all conversations to be legally confidential and protected, but that’s not going to happen. Except as stated above I will try to keep all communications private unless the writer gives permission to pass it on.
• I’ve added a new section titled “Back Page” where I will post current notes and happenings. This will allow readers to find the new stuff without having to search through all the old stuff, which is still fairly current.

Amateur Rocket Launch Assist (ARLA)

This report describes two non-rocket launch assist stages for amateur rockets. The first stage is expected to provide up to 2,000 fps to the amateur rocket. The second stage is expected to provide 5,000 fps and 100,000 ft altitude before rocket ignition. There is some potential for extending these to 7,000 fps and 120,000 ft. The technologies described are garage-level and the materials can be locally acquired.

Because this concept describes devices with high potential and kinetic energies the reader must review the “Safety and Legality Warnings” chapter before considering building any of the described equipment.

Table of Contents

• Safety and Legality Warnings
• ARLA Introduction
• Launch Tubes
  • Launch Tube Basics
  • Example Launch Tube Designs
• Ramjets
  • Ramjet Basics, Part 1
  • Ramjet Basics, Part 2
  • Review of the Bomarc Ramjet
  • Garage Level Ramjet Construction
• Rockets
• Sabots and Pistons
• Testing Methodologies
• Appendices
  • Appendix A – Additional Notes on Launch Tubes Part 1, and Part 2
  • Appendix B – Additional Notes on Ramjets
  • Appendix C – Physics of Motion
  • Appendix D – References
• Ramjet Simulation Code, RJSC.ZIP