The Art of the All-PVC Amateur Hybrid Rocket Engine

Evan Daniel

Last Updated March 21, 2006

Introduction

For some time now, I've been trying to find an inexpensive, reliable way to launch and debug experimental rocket electronics. After reading Alberto Gassol's work on PVC hybrid engines, I decided to investigate that route. My goal was to create a motor that cost less than $10 to fly, with less than half an hour of labor per reload. After some experimentation, I believe I have met that goal, with an all-PVC hybrid that costs under $10 for the tank and about $5 for a reload.

Safety

Before continuing, I'd like to make a brief mention of the safety issues involved. Rockets can be very safe and fun to build and fly, if proper precautions are followed. Because of the energies involved, rocket engines have an inherent potential to be dangerous if not handled with a proper respect for safety issues. Richard Nakka has a nice page on rocket safety. Nitrous oxide also has some unique hazards, mostly because it is a liquefied compressed gas and a combustion-supporting oxidizer. It is also a theoretical possibility for it to decompose in a self-sustaining fashion; however, this does not appear to be a large risk. Air Liquide has an MSDS for nitrous oxide. In short, the only way to be safe about it is to never be near the engine when it is pressurized.

Design, Theory, and Testing

Construction

Movies

Warning: these haven't yet been edited, and are fairly large. You may want to right-click and hit "save link target as..." to download the file rather than viewing in the browser, depending on your browser's configuration. Right now they're unavailable for bandwidth reasons (apparently they're popular!); they should appear on Google Video shortly, which will take care of bandwidth concerns.

Launch of the Orange Bird 2 (9.5 MB)

Launch of the Blue Moon (106 MB)

About Me

I'm Evan Daniel. I've been flying rockets for a bit over a year now, at the Whitakers launch site in Whitakers, North Carolina, USA. I live in Durham, North Carolina. I've studied Computer Science at NC State University, but am contemplating a career change into Rocket Science / Aerospace Engineering.

My current project is the PVC hybrid motor shown on these pages. Once I have these fully working and debugged, I plan to work on electronics, starting with a test stand data recorder and then probably an altimeter / flight data recorder. After that, I might resume some earlier work in solid propellants, or I might do something else -- I'll see when I get there. Long term, I have goals of working on a high altitude flight, and would like to do some work on bipropellants if I can find the resources (like a test site, and probably a machine shop).

I can be reached at "evand nospam pobox nospam com." I also follow and occasionally post on several rocketry-related mailing lists.

Launch Plans

I plan to be at the March 26 launch at Whitakers, flying my PVC hybrids. I'm going to attempt again to fly the Blue Moon on the 3/16" injector motor (this launch was planned for February, but was scrubbed due to electronics failures).

I'm also planning to be at WELD in April, flying something yet to be determined. Likely either attempts to debug the hybrids or experiments with them, depending on the March results.