Article View: sci.space
Article #8415Re: Model Rocketry
From: R. M. Jungclas
Date: Fri, 27 Jan 1989 19:51
Date: Fri, 27 Jan 1989 19:51
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I have been trying to respond to this for a few weeks, but things
really bogged down at work and things are only slowly returning to
normal. If you requested a list of rocket manufacturers, I will email
you a copy as soon as I get caught up. So better late than never ...
>Model rocketry may claim millions of accident free launches as a proud
>heritage. That is fine for a pure MODEL hobby that is done for family
>fun, for creative pleasure and so on. I won't knock it. I used to be a
>model RAILROADER myself. Same difference.
While I concede that the largest percentage of model rocket launches
are done for fun, model rocketry/high power rocketry is more than a
"pure MODEL hobby." Both of these have made positive research
contributions. Unlike model railroading and other "imitation" hobbies,
once a model rocket leaves the launcher all aerodynamic and structural
principles apply. Only the magnitude of the forces differ. In many
cases, the magnitude of forces, etc. are insignificant in studying the
research issues; major aerospace companies use a "static" modeling
capacity in studying research issues and designs. Because of the
medium used in model/high power rocket construction, is often easier,
safer, and considerably less costly to study structural failure.
For example, it is easy to build a vehicle that exceeds "the speed
of balsa." When this happens the forces applied to the vehicle exceed
the tensile strength of balsa fins. Professional rocket engineers
obviously don't talk about balsa, but the underlying principles are
identical. There have even been investigative efforts into what it
would take to place model/high powered rocket into orbit. Finally,
there is also an R&D mechanism present within the NAR and presumably
within Tripoli. The bottom line is that model/high power rocketry is
what YOU make out of it. It can be a inexpensive way to complete
research.
Let me now site several research examples:
1. In 1966 James Barrowman developed a method for finding the
stability of new model rocket designs. This approach eliminated
the previous trial by error approach and used a greatly simplified
approach based on stability design by professional rocket
engineers. This technique so greatly simplified and produced
reliable results that the stability design used by professional
engineers adopted the approach for sounding rocket designs.
2. Considerable effort have gone into developing highly accurate
altitude/speed prediction programs that take into account every
conceivable factor and yet are available for most microcomputers.
3. A friend of mine has developed a miniature video camera, transmitter,
and on board computer that fits inside an Estes PNC-80K nose cone -
about 2.6 inches in diameter and 4 or 5 inches in length. The
battery pack by comparison is almost as big!. This design was
studied by a major robotics/machine vision corporation and Lionel
trains who within the past year released a similar but drastically
less complex video camera of their own. The original rocket design
was considerably larger. This person was not the first to fly a
video camera, but it illustrates what I call the "American" approach
(ie miniaturization) vs. the "Russian" approach (strapping an
off-the-shelf video camera/recorder to front end of a launch
vehicle and flying it)
4. By the late 1960's, model rockets had demonstrated the Space Shuttle
concept of launching like a rocket and gliding back to earth
identical to present real Space Shuttle concept. (True, we didn't
make it to orbit, nor did the hobby invent the concept)
5. >A high power rocket built by North Coast Rocketry and carrying a
>research payload was recently launched (past 6 months) from Cape
>Canaveral after months of red tape.
Mark Johnson (Mark.Johnson@Wichita.NCR.COM) reports info on LOFT-1:
The flight was launched from Canaveral Air Force Station on November
17, 1988 at 0745 EST, reaching an altitude of 3.25 miles. (LC 47 was
the launch site, using a modified Loki-Dart launcher; telemetry was
set up at LC 41). The vehicle itself and the Vulcan N5000-20 motor
performed essentially perfectly, although E-Prime's aneroid
main-chute deployment feature failed to eject...it was rigged to
reduce drift by holding the main chute until the vehicle reached an
altitude of 3000 feet on the way down, and it got fried by the
ejection charge on the motor, which was used to eject a 24" (or so)
drogue chute. The drogue chute thus was the only recovery system
on the bird, which suffered only minor damage on splashdown.
The flight vehicle was recovered within 1 hour of the flight, and
was opened up in front of the news media shortly thereafter.
Telemetry data was received the entire time the vehicle was airborne.
Several NAR members were involved in the project in various ways:
(The LOFT effort is NOT an NAR activity, but rather one that some
NAR members branched out into by applying their model rocket
technology and experience.)
Matt Steele, part-owner of North Coast Rocketry, designed the
vehicle and did some or most of the construction. Project
engineer with Morton Thiokol-Huntsville.
J. Wayne McCain, a PhD candidate at Univ. of Alabama/Huntsville,
was payload integration manager. Wayne is an amateur radio
operator.
David Babulski, longtime MR telemetry builder (his series is
currently running in AmSpam), ran the telemetry ground station
for the flight. Dave is employed as a curriculum developer/trainer
with Harris/3M in Atlanta (copiers, fax machines, etc.)
Dave is also an amateur radio operator.
Some other details...one of the original payloads scheduled to be
launched on LOFT was a high-school biology experiment, coordinated
by Dave Babulski, from Brookwood High School (east suburban Atlanta).
When LOFT was repeatedly delayed, Dave, Wayne, and North Coast put
together a replacement vehicle, called BABE-2 (the original
experiment package was BABE-1), which was flown from Huntsville
(Redstone Arsenal) last spring. This vehicle was powered by a
Vulcan I283 and reached an altitude of 10,000 feet...15,000 had been
projected but a structural failure occurred in the bird at Mach 2+
causing the vehicle to break up and the payload did a free-ballistic
number. The experiment package was recovered with only minor damage,
somewhat surprisingly; I think telemetry even survived the aerial
breakup although it stopped rather suddenly on meeting the region of
extreme drag coefficient known as earth.
Another friend of mine reports that details of this flight are reported
in a recent issue (January?) of Discovery magazine.
>But the kind of rocketry that is likely to produce useful results is
>also unlikely to be able to sustain such a record. If it did, it would
>not be pushing the state of the art and would not be accomplishing
>anything real.
Again, we must look at volume of "fun" launches and subtract these.
Don't confuse safety with failure. Pushing the state of the art does
not necessarily imply lack of safety. Pushing the state of the art
does mean failures and correcting the reason for these failures.
>I found the article on Model Rocketry quite informative and
>interesting, but I must say that I'm personally not interested in
>building 'model' rockets. I've not really been in the hobby at all, but
>if I were I'd definitely go into the amateur rocketry category with
>intent to test new untried or undertried concepts and possibly to put
>something in orbit. With or without permission.
By the poster's own admission, he has never checked out the details
of the hobby. Any good researcher will check previous work done in
their field, related fields and any activity that could benefit
their research. Model/High power rocketry can provide an excellent,
inexpensive and a safe way without all the legal hassles
in which "to test new untried and undertried concepts" without
re-inventing the wheel. High power rocketry can trace it roots back
to research and/or military applications. This does not imply that
model/high power rockets are useful in every case; only that if they
can be used it probably in researcher's best interest to do so.
A good reference for a more detailed, in depth treatment of model
rockets and theory/research behind them, consult G. Harry Stine's
"The Handbook of Model Rocketry" that may be found in many libraries.
>I personally know someone who has successfully fired a large
>(suborbital class) teststand engine with an interesting hybrid type
>fuel system. He and his crew did so in a very isolated area with
>appropriate safety precautions. Their method of dealing with
>bureaucracy is one that Admiral Grace Hopper would have approved of:
>"It's easier to ask for forgiveness than to get permission." What they
>don't know can't be regulated.
No one is going to stop you from developing or static testing anything
on your own property, provided you don't create a public nuisance (ie.
noise) and don't create a public safety hazard (ie building your own
nuclear warhead). However, the minute that you do this on public
property, or in the national airspace, regulatory agencies will
subject you to close scrutiny. Do you honestly think that an attempt
to launch into orbit will occur without the appropriate agencies
finding out about it? You might start to get away with it, but I
guarantee that sooner or later you'll get caught and your research
project is likely to be destroyed in the process. Moreover, ignorance
is no excuse. I know of a case in which an individual attempted to
use this approach that resulted in severe financial penalties and an
agreement by the party involved to keep him out of jail that prevents
him from attempting any rocket activities for life. Turns out that
regulatory agencies really make examples out of these cases. So if you
pursue this course of action be prepared for the consequences.
R. Michael Jungclas UUCP: att!ihlpb!rjungcla
AT&T Bell Labs - Naperville, IL. Internet: rjungcla@ihlpb.att.com
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!nrl-cmf!ukma!uflorida!haven!rutgers!att!ihlpb!rjungcla From: rjungcla@ihlpb.ATT.COM (R. M. Jungclas) Newsgroups: sci.space Subject: Re: Model Rocketry Message-ID: <9483@ihlpb.ATT.COM> Date: 27 Jan 89 19:51:09 GMT Organization: AT&T Bell Labs - Naperville, IL. Lines: 179