Comments: Consumer Aerospace

This reminded me of something I've been curious about. I know the motors in the Estes rockets I built as a kid are solid-fuel motors. What's a hybrid motor?

Posted by Victor at October 19, 2004 02:16 PM

Most hobby high power motors are solid too, they just use Ammonium Perchlorate instead of black powder as the basis for the fuel grain (so does the Space Shuttle's side pod engines). These solid motors include an oxydizer in the fuel grain mixture.

A hybrid motor uses a solid fuel grain without any oxydizer added (for instance polypropolene plastic or good ol' PVC). In these motors the oxydizer must be added, and that's where the liquid nitrous oxide comes in. It's injected into the motor as the fuel grain burns to boost thrust to useful levels. Solid fuel + liquid oxydizer = hybrid.

Liquid propellant motors use a liquid fuel and a liquid oxydizer. These tend to be very finicky, but are easily the most powerful by today's technology. Using liquid propellant is outside of "hobby rocketry" and is considered "amatuer rocketry", but is just as accurately called "semi-pro" rocketry. It's for the folks who really know what they're doing. A good example are the UK club MARS: http://www.mars.org.uk/ "Britain's Amateur Space Programme".

Posted by Ted at October 19, 2004 04:41 PM
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