Monday, January 4, 2010

Amateur Experimental vs High Powered Rocketry

The other day someone that knew I was "into" rocketry said, "I saw this show on TV where these guys put rocket motors onto a ten foot mock up of Dorothy's house from the Wizard of Oz and shot it into the air". I saw this show, it was entertaining, but that's not the type of rocketry that I'm "into". The above example falls into the High Powered Rocketry or HPR category for me. To be fair, it is at one extreme end of the HPR spectrum. I'm not at all against HPR, it's just doesn't really excite me. Assembling a kit, commercial motor, propellant, and flying it doesn't teach you the engineering of rocketry or at least it doesn't take you very far below the surface. I know that some HPR launches have "experimental" days that allow people to fly motors that they have made with propellant that they have cast themselves, but even at those launches most of the motors are of a very similar design and most of the propellant is just a slightly different variation of the same stuff.
The photo above is of a two stage vehicle built and flown by Bill Claybaugh at the RRS last October. The booster is a cluster of four RRS "class" motors and the sustainer is a single "class" motor. The class motor was developed by the RRS to use for their introductory solid propellant class that they've taught for a number of years. It's been a while since I took the class, but as I recall the motor produces around 300lbs. of thrust for three seconds, so the booster propelled this thing out of the tower with 1200lbs. of thrust. I don't think this is the most interesting amateur rocket that I've seen, but it would certainly look right at home in the pages of Richard Morrow's "Small Sounding Rockets". I can't help but think that the same five motors at a HPR event would be lazily propelling a scaled-up version of some Estes model rocket to three or four hundred feet.
It's not unusual to go to a launch at the RRS or FAR and see half a dozen rockets fly, far fewer than you would see at a typical HPR event. The difference is that those six rockets would likely be completely different from each other. Solids, liquids, Lox/Kerosene, Hydrogen Peroxide, Steam, Zinc/Sulfur, Sugar, HTPB, and on and on. Now that, I'm into!


R2K said...

Wow that rocket looks so nice! Any info on the performance and altitude? The RRS web page is only seldom updated it seems, like once a decade.

Randy Dormans said...

I don't have the specs available, I recall hearing the altitude was expected to be around 40,000 ft. The vehicle turned into the wind upon leaving the tower, but the sustainer straightened out once ignited. Ignition was visible and audible from the ground. As far as I know the vehicle was not recovered.
Unfortunately the RRS web site is about as inactive a site as you can find :(

Anonymous said...

An analysis of the flight of this vehicle is available at under "flight reports"

Anonymous said...

I can't agree with you more. Most amateur rocketry seems to spend more time on the paint job then on any kind of engineering or science. Buying a bunch of kit tubes, fins, and rocket motors and applying glue, paint, and not-screwing-up just doesn't do it for me. I get excited by new things, and people daring to push the envelope. One of my favorite rockets I ever developed and flew was based on a joking challenge - he dared me to make a rocket from 7:3:1 flash powder. I did it with 1.8% phlegmatizer. Only 25% CATO'd, but boy were those amazing CATOs.