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Frequently Asked Questions
What is a Hybrid Rocket?
In it's simplest form, a hybrid rocket is one that uses a solid fuel, usually some type of rubber or plastic, and a liquid oxidizer, such as liquid oxygen or hydrogen peroxide.

The fuel is most often shaped into a cylinder with a hole down the middle through which the oxidizer passes. The fuel is vaporized and burns with the oxidizer, the products of which pass through a rocket nozzle, thereby producing thrust.

A hybrid rocket engine is typically very, very clean, second only to oxygen/hydrogen fueled rockets.

Hybrids rockets are much more reliable than their liquid counterparts (partially due a significant reduction in the number of moving parts).

Unlike solid rocket motors, hybrid rocket motors are not explosive by nature. Also unlike solids, hybrids can be shutdown and restarted, and they can be throttled, though not to the degree generally available with a liquid rocket motor.

Why are hybrid rockets so great?
  1. Increased reliablity over solid rockets and liquid rockets
  2. Increased safety over solid rockets and liquid rockets
  3. Performance (Isp) at least equal to solid rockets
  4. Environmentally clean exhaust products
  5. Significant cost savings over both liquid rockets and solid rockets
  6. Why aren't there any commercial hybrid rockets?
    1. Solid rockets and liquid rockets got a several billion dollar headstart (thanks to the cold war).
    2. Stability of large LOX driven hybrids has been a problem for many years (just ask anyone who worked for AMROC), but the problem has been solved.
    3. Politics. It costs alot to launch a rocket these days, and some people want to keep it that way, or else they'd be out of business
    4. Intertia. "We've always done it this way."
    5. Safety concerns. Now just what would the crew of the Challenger say about this topic?
    6. Who is HybridGuy?
      Dr. HybridGuy, Ph.D., is a propulsion analyst, a.k.a. rocket scientist.
      How do I build a hybrid rocket?
      If you are interested in building an small hybrid rocket, start at RocketryOnline and look for rocketry clubs in you area. Talk with others who build these things.

      This site does NOT contain the information required to construct a hybrid rocket. The same cannot be said for some of the links.

      Another good place to start is the Rec.Models.Rockets FAQ.