ROCKETS AND CANNONS
Rockets and cannon are generally thought of as heavy artillery.
Perpetrators of violence do
not usually employ such devices, because they are
difficult or impossible to acquire. They are
not, however, impossible to
make. Any individual who can make or buy black powder or pyrodex
can make such
things. A terrorist with a cannon or large rocket is, indeed, something to
fear.
ROCKETS
Rockets were first developed by the Chinese several
hundred years before
the myth of christ began. They were used for entertainment, in the form
of
fireworks. They were not usually used for military purposes because they were
inaccurate, expensive, and unpredictable. In modern times, however, rockets
are used
constantly by the military, since they are cheap, reliable, and have
no recoil. Perpetrators
of violence, fortunately, cannot obtain military
rockets, but they can make or buy rocket
engines. Model rocketry is a popular
hobby of the space age, and to launch a rocket, an engine
is required. Estes,
a subsidiary of Damon, is the leading manufacturer of model rockets and
rocket
engines. Their most powerful engine, the "D" engine, can develop almost 12
significant distance.
Other companies, such as Centuri, produce even larger
rocket engines, which develop up to 30
lbs. of thrust. These model rocket
engines are quite reliable, and are designed to be fired
electrically. Most
model rocket engines have three basic sections. The diagram below will
help
explain them.
_________________________________________________________
|_________________________________________________________| — cardboard
\ clay | - - - - - -
- - - - | * * * | . . . .|c| casing
\_______| - - - - - - - - - | * * * | . . . |l|
_______ - - - thrust - - - | smoke | eject |a|
/ clay | - - - - - - - - - | * * * | . . .
.|y|
/________|_____________________|_______|________|_|_______
|_________________________________________________________| — cardboard
casing
The clay nozzle is where the igniter is inserted. When the area labeled
"thrust" is ignited, the "thrust" material, usually a large single grain of a
hot, rapidly
expanding gasses out the narrow nozzle, pushing the rocket
forward.
After the
material has been consumed, the smoke section of the engine is
ignited. It is usually a
slow-burning material, similar to black powder that
has had various compounds added to it to
produce visible smoke, usually black,
white, or yellow in color. This section exists so that
the rocket will be
seen when it reaches its maximum altitude, or apogee.
When it
is burned up, it ignites the ejection charge, labeled "eject".
The ejection charge
is finely powdered black powder. It burns very rapidly,
exploding, in effect. The explosion of
the ejection charge pushes out the
parachute of the model rocket. It could also be used to
ignite the fuse of a
bomb…
Rocket engines have their own peculiar labeling
system. Typical engine
labels are: 1/4A-2T, 1/2A-3T, A8-3, B6-4, C6-7, and D12-5. The letter
is an
indicator of the power of an engine. "B" engines are twice as powerful as
"A"
engines, and "C" engines are twice as powerful as "B"
engines, and so on. The
number following the letter is the approximate thrust of the engine,
in
pounds. the final number and letter is the time delay, from the time that the
thrust
period of engine burn ends until the ejection charge fires; "3T"
indicates a 3
second delay.
NOTE: an extremely effective rocket propellant can be made by mixing
aluminum
dust with ammonium perchlorate and a very small amount of iron oxide.
The
mixture is bound together by an epoxy.
BASIC ROCKET BOMB
A rocket
bomb is simply what the name implies: a bomb that is delivered
to its target by means of a
rocket. Most people who would make such a device
would use a model rocket engine to power the
device. By cutting fins from
balsa wood and gluing them to a large rocket engine, such as the
Estes "C"
engine, a basic rocket could be constructed. Then, by attaching a
"crater
maker", or CO2 cartridge bomb to the rocket, a bomb would be added. To
insure
that the fuse of the "crater maker" (see sect. 4.42) ignited, the clay
over
the ejection charge of the engine should be scraped off with a plastic tool.
The
fuse of the bomb should be touching the ejection charge, as shown below.
____________ rocket engine
| _________ crater maker
| |
| |
V |
_______________________________V_
|_______________________________| ______________________
\__| - - - - - -|***|::::| ___/ # # # #
# # # # # # # \
__ - - - - - -|***|::::|—fuse— # # explosive # # )
/ | - - - - -
-|***|::::| ___ # # # # # # # # # # # /
/___|____________|___|____|____
\_______________________/
|_______________________________|
thrust> - - - - -
-
smoke> ***
ejection charge> ::::
Duct tape is the best way
to attach the crater maker to the rocket
engine. Note in the diagram the absence of the clay
over the ejection charge
Many different types of explosive payloads can be attached to the
rocket, such
as a high explosive, an incendiary device, or a chemical fire bottle.
the rocket
flies straight. The fins should look like the following diagram:
|\
| \
| \
| \ <——— glue this to rocket engine
| \
| \
| \
| |
| |
| |
leading edge |
——-> |
| |
| | trailing
edge
| | <——–
| |
| |
| |
| |
\_____/
that they are
rounded. This will help make the rocket fly straight. A two
inch long section of a plastic
straw can be attached to the rocket to launch
it from. A clothes hanger can be cut and made
into a launch rod. The segment
of a plastic straw should be glued to the rocket engine
adjacent to one of the
fins of the rocket. A front view of a completed rocket bomb is shown
below.
|
fin | <—— fin
| | |
| | |
| __|__ |
—————| |—————
\_____/
|o <———– segment of
plastic straw
|
|
| <—— fin
|
|
By cutting a coat
hanger at the indicated arrows, and bending it, a
launch rod can be made. After a fuse is
inserted in the engine, the rocket is
simply slid down the launch rod, which is put through
the segment of plastic
straw. The rocket should slide easily along a coathanger, such as the
one
illustated on the following page:
____
/ \
| |
cut
here _____ |
| |
| |
| / \
V / \
_________________/
\________________
/ \
/ \
/____________________________________________\
^
|
|
and here ______|
Bend wire to this shape:
_______ insert into straw
|
|
|
V
____________________________________________
\
\
\
\
\ <———
bend here to adjust flight angle
|
|
|
|
|
| <———- put
this end in ground
|
LONG RANGE ROCKET BOMB
Long range
rockets can be made by using multi-stage rockets. Model
rocket engines with an "0"
for a time delay are designed for use in
multi-stage rockets. An engine such as the D12-0 is
an excellent example of
such an engine. Immediately after the thrust period is over, the
ejection
charge explodes. If another engine is placed directly against the back of an
"0" engine, the explosion of the ejection charge will send hot gasses and
burning
particles into the nozzle of the engine above it, and ignite the
thrust section. This will
push the used "0" engine off of the rocket, causing
an overall loss of weight.
The main advantage of a multi-stage rocket is that it loses weight as
travels, and it
gains velocity. A multi-stage rocket must be designed
somewhat differently than a single stage
rocket, since, in order for a rocket
to fly straight, its center of gravity must be ahead of
its center of drag.
This is accomplished by adding weight to the front of the rocket, or by
moving
the center of drag back by putting fins on the rocket that are well behind the
rocket. A diagram of a multi-stage rocket appears on the following page:
___
/
\
| |
| C |
| M | —— CM: Crater Maker
| |
| |
|___|
|
|
| |
| |
| C | —— C6-5 rocket engine
/| 6 |\
/ | | | \
/ |
5 | \
/ |___| \ —- fin
/ /| |\ \
/ / | | \ \
/ / | | \ \
/ / | C | \
\
| / | 6 | \ |
| / | | | \ |
| / | 0 | \ |
|/ |___| \|
| / \ |
\______/ ^ \______/ ——- fin
|
|
|
|
C6-0 rocket engine
Two, three, or even four stages can be added
to a rocket bomb to give it
a longer range. It is important, however, that for each additional
stage, the
fin area gets larger.
-= RFLAGG =-
‘97
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