Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02459675 2006-12-21
Patent Application
GUN BARREL FOR LAUNCHING PROJECTILES
FIELD OF THE INVENTION
The present invention relates to the field of gun barrels for the launching of
projectiles.
BACKGROUND OF THE INVENTION
It has long been thought possible to use large guns to assist with the
launching of devices into
orbit. One means of potentially accomplishing this is to use a very large gun
barrel to launch
a projectile, such as a rocket with a satellite payload, beyond the lower
atmosphere of the
earth, and then to fire the rocket so that it will cause the satellite to
reach orbital velocity and
subsequently enter into an orbital path. The rocket is launched to a height
that is above the
lower atmosphere, as it is in the lower atmosphere that most drag occurs and
where most
rockets use up a large quantity of their fuel. By firing the rocket in the
near vacuum of the
upper atmosphere, less fuel is required by the rocket to achieve orbital
velocity. Since a gun
barrel can be used more than once, gun launching provides an economical first
stage for
launching satellites. Additionally, a gun launch can be used in almost any
weather condition.
Long-range artillery capable of launching projectiles a significant distance
was first developed
and used in WW I. For example, the Paris gun, when fired at an angle of 50
degrees, was able
to send a projectile to an altitude of 43.2 km, well past the 12 km that is
generally considered
to be the "lower atmosphere". The Max E gun could fire a 740 kg projectile to
a maximum
range of 47 km. The Paris Gun and the Max E, if fired at a 90-degree angle to
the earth's
surface could have fired projectiles past the lower atmosphere. The 800 mm
Gustav
developed in WW II could fire a 4800 kg shell a distance of 47 km, and a 7100
kg shell a
distance of 38 km.
In the early 1960's, Gerald Bull was involved with a project called HARP, an
acronym for
High Altitude Research Project, which program involved the use of large guns
to fire
projectiles and rockets to high altitudes. The HARP program was cancelled
before its goal of
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achieving orbital entry of a device was obtained, because the system was too
expensive and
the available technology would not support further research. However,
altitudes of 110 miles
were reached, with 400-pound projectiles.
Advances in the development of rockets, new types of rocket fuels, new
propellants for
artillery, and advances in the design of smaller satellites, such as nano and
pico satellites,
which can weigh as little at 10 ounces, now make the gun-assisted launching of
orbital
devices, such as satellites, possible.
One component of a gun launch apparatus for the launching of a projectile is
the gun barrel.
To be able to assist in achieving orbital launching of a device, the gun
barrel must be very
large. Traditionally, very large gun barrels have been comprised of steel, to
provide the
required strength and rigidity. However, steel gun barrels of the size
required for gun-assisted
orbital launching are expensive to make and heavy. The weight of a large steel
gun barrel is a
factor that significantly interferes with the ability to move or vary the
location of the gun
barrel, and the latter problem limits the potential to use the same gun barrel
to repeatedly
launch satellites into orbit, as the barrel is always pointed to the same
position.
The cost of putting a satellite into orbit is currently very high. Advances in
rocket and
satellite technology suggest that it is worthwhile to revisit the concept of
using large guns to
assist with the launching of satellites into orbit, particularly if it will
lower the cost of satellite
launching. One way to lower the cost is to make a gun barrel that is less
expensive than a
steel gun barrel.
SUMMARY OF THE INVENTION
There is disclosed herein a gun barrel for use in the launching of projectiles
for a number of
applications. As examples only, the gun barrel may be used in satellite
launching operations,
in artillery operations or in fire-fighting operations.
The gun barrel of the present invention may be less expensive to manufacture
than a steel gun
barrel, may be less heavy than steel and is sufficiently strong for the
purposes mentioned
herein, namely for the firing of projectiles. As examples only, the gun barrel
may be used to
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launch: rockets with satellite payloads, artillery, devices that can be used
to intercept nuclear
weapons, or large drums of water.
In one embodiment, the invention is a gun barrel, with
(a) a breech end and an open end;
(b) a bore disposed between the breech end and the open end,
(c) an outer support layer on an outside surface of the gun barrel;
(d) an inner support layer lining the bore of the gun barrel, and
(e) a layer compressible material disposed between the outer support layer and
inner support layer, said compressible material having a compressive strength
of at least 10 mPa and having a compressive strength that is less than the
than
the compressive strength of one of (a) the inner support layer and (b) the
outer
support layer.
The breech end may be closed, or closeable, for example by use of a breech
plug.
The outer support layer and the inner support layer can be comprised of a
metal, for example,
steel. The compressible material can be concrete. Alternatively, it may be
another type of
compressible material with a compressive strength of greater than 10 mPa, for
example a
plastic material. The layer of compressible material can be reinforced.
In one embodiment, the gun barrel comprises an outer layer of steel on the
outside surface of
the gun barrel, an inner layer of steel lining the bore of the gun barrel, and
a layer of concrete
disposed between the outer layer of steel and the inner layer of steel, said
concrete having a
compressive strength of at least 10 mPa. The gun barrel may have a breech end
that is one of
either (a) closed or (b) closeable, and a second end wherein the bore is open.
In another embodiment, the invention is a gun barrel with a breech end and an
open end and a
bore disposed between the breech end the open end, comprising:
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(a) a breech portion made of metal, and
(b) an elongate portion adjacent to the breech portion, said elongate portion
further
comprising:
(i) an outer support layer on an outside surface;
(ii) an inner support layer lining the bore of the gun barrel, and
(iii) a layer compressible material disposed between the outer support layer
and inner support layer, said compressible material having a
compressive strength of at least 10 mPa and having a compressive
strength that is less than the than the compressive strength of one of (a)
the inner support layer or (b) the outer support layer.
The breech end may be closed or closeable, for example with a breech plug.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1(A) is an elevational view of an embodiment of the gun barrel of this
invention, with
the inside parts shown by dashed lines. Figure 1(B) is a cross section taken
along line I-I of
Figure 1(A).
Figure 2 is an elevational view of a portion of an embodiment of the gun
barrel of this
invention, showing reinforcement of the layer of compressible material.
Figure 3 is an elevational view of an embodiment of the gun barrel of this
invention, with the
inside parts shown by dashed lines.
Figure 4 is an elevational view of an embodiment of the gun barrel of this
invention, with the
inside parts shown by dashed lines.
Figure 5A is a longitudinal cross-sectional view of an embodiment of the gun
barrel of this
invention. Figure 5B is a longitudinal cross-sectional view of the muzzle end
of an alternative
embodiment of this gun barrel of this invention.
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Figure 6 is a longitudinal cross-sectional view of an embodiment of the gun
barrel of this
invention showing a breech portion that is entirely comprised of metal.
Figure 7 is a longitudinal cross-sectional view of an embodiment of the gun
barrel of this
invention showing a gun barrel that has a stabilizer at the base.
5 DETAILED DESCRIPTION
Reference will now be made to Figures 1-7, which show different embodiments of
the gun
barrel. Figure 1 shows an embodiment of the gun barrel 10 which includes an
outer support
layer 12, an inner support layer 14, and disposed therebetween, a layer of
compressible
material 16. The inner support layer 14 defines a bore 18, along which a
projectile 20 will
travel, from a breech end 22 to a muzzle end 24.
Although referred to herein as a gun barrel, the gun barrel may alternatively
be referred to as a
launching tube, a cannon, a mortar, or the like.
Layers 12 and 14 are referred throughout herein as support layers. As used
herein, a "support
layer" is a layer that may, among other things, resist cracking and
deformation following
firing of a projectile from the gun barrel, and may be able to be used for
repeated firing of a
projectile from the gun barrel. The support layers prolong the useable life of
the gun barrel.
The support layers may be made of a metal, which as used herein includes
alloys. Steel,
including high-carbon steel is a metal that may be used in layers 12 and 14 of
the gun barrel
10. Other metals, for example, titanium, may also be used. Any non-metal
material now
known or hereafter developed, that would be capable of functioning as a
support layer, is also
intended to be included herein. For example, coated cardboard and polymeric
materials, for
example plastics, or composite materials, may be used as support layers in
some embodiments
of the gun barrel. As is apparent, outer support layer 12 and inner support
layer 14 may be
comprised of materials that are different from one another.
The outer support layer 12 provides tensile strength to the gun barrel both
during the recoil
and while the projectile travels up the barrel. The outer support layer 12
confines the layer of
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compressible material 16 during the firing of the projectile, should the layer
of compressible
material crack or otherwise fall apart. Ideally, the outer support layer will
remain intact
through repeated uses of the gun barrel.
In one embodiment, shown in Figure 1, the outer support layer is comprised of
steel. Many
different grades, thicknesses or types of steel may be used, including 12.5 mm
thick, A105
forged carbon steel.
The outer diameter of the gun barrel may be constant from breech end 22 to
muzzle end 24, as
shown in the embodiments shown in Figures 1 and 5. Alternatively, the outer
diameter of the
gun barrel may decrease, progressing from breech end to muzzle end, as shown
in the
embodiments shown in Figures 3 and 4.
The inner support layer 14 lines bore 18. The inner support layer functions,
in particular, to
provide a lining for bore 18 which will enable a projectile to be fired from
the gun barrel and
also to physically separate the projectile from the layer of compressible
material 16. Ideally,
the inner support layer will remain intact through repeated use of the gun
barrel. The material
from which the inner support layer is made will depend largely upon the amount
and type of
propellant used in the gun barrel.
In one embodiment, the inner support layer 14 in a portion of the bore 18 that
is closer to, or
at, the breech end, may be made of a material that is particularly resistant
to the explosive
forces generated upon firing of the projectile 20 from the gun barrel 10. For
example,
hardened steel or titanium may be used in this portion of the gun barrel.
These metals are
more resistant to damage caused by launching of projectiles than are other
metals, and
therefore their use may increase the useable life of the gun barrel. Although
the portion of
bore 18 that is covered by this more resistant material may vary, generally it
is sufficient that
the more resistant material extend about 20% up the length of the bore 18 from
the breech
end. A gun barrel 310 with a portion 319 of the bore 318 made of a
particularly resistant
material, is shown in Figure 5A.
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In one embodiment, shown in Figure 1, the inner support layer is comprised of
steel. Many
different grades, thicknesses or types of steel may be used, including 12.5 mm
thick, A105
steel. The type of steel used will in large part depend upon the propellant
used.
The outer and inner support layers may vary a great deal in thickness, as
between different
embodiments of the gun barrel. The thickness of either of these layers will
depend upon the
thickness of the other layers of the gun barrel. For example, if the inner
support layer, or
layer of compressible material, or both, are particularly thick, the outer
support layer may be
thinner than in a similarly-sized gun barrel where the inner support layer, or
layer of
compressible material, or both, are less thick. What is important is that each
layer is capable
of performing the function required of it, and that all three layers combined
create a gun barrel
that is strong enough to be fired repeatedly.
At the muzzle end 24 of the gun barrel 10, the inner support layer 14 and the
outer support
layer 12 may meet or overlap, in order to enclose the compressible material.
This
embodiment is shown in Figure 5B, where the inner support layer 414 extends
around the end
of the gun barrel 410, to completely cover the layer of compressible material
416.
Alternatively, the compressible material may remain exposed, as is shown in
Figure 5A,
where the layer of compressible material 316 is exposed at the muzzle end of
the gun barrel
310.
The breech end 22 of the gun barrel 10 may be closed. A gun barrel made in
this way would
therefore be loaded with propellant and the projectile from the muzzle end.
This embodiment
is shown in Figures 1, 3 and 4. For a gun barrel with a closed breech end, the
layer of
compressible material may be thicker at the breech end than elsewhere in the
gun barrel.
Alternatively, the gun barrel may be designed to be loaded from the breech
end. If the gun
barrel is to be loaded from the breech end, the breech end of bore 18 will be
open and will
need to be closed prior to firing a projectile. In this embodiment, an example
of which is
shown in Figure 5A, a breech plug 323 may be threaded into the bore 318 before
firing of the
projectile. The size of the breech plug will vary, however for a large gun the
breech plug
would likely be upwards of one meter in length, and preferably about 3 meters
long. The
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compressible material may be enclosed by one or both of the inner and outer
support layers,
or it may be exposed.
The diameter of bore 18 may be constant or variable along its length. Figure 1
shows
embodiment where the inner diameter of bore 18 is variable, comprising a wider-
diameter
section closer to the breech end 22, a narrower-diameter section closer to the
muzzle end 24,
and a transition region 25, the extent of which is represented by arrow 28.
The extent of the
wider-diameter section is represented by arrow 26 and the extent of the
narrower-diameter
section is represented by arrow 36. Figure 5A shows an embodiment 310 with an
inner
support layer 314, an outer support layer 312, a layer of compressible
material 316, and a bore
318 that is of constant diameter along its entire length. A gun barrel with a
constant inner
bore diameter may be used, however it is not as efficient as one in which the
diameter reduces
as one progresses from breech to muzzle. In particular, it may require more
propellant than a
similarly sized gun barrel with a bore 18 of decreasing diameter. A decrease
in bore 18
diameter proceeding from breech to muzzle serves to focus the propulsive
forces and thereby
eject the projectile at a greater speed than with a constant diameter bore of
the same length.
Figures 3 and 4 show embodiments in which the diameter of bore 18 is reduced
more than
once.
The gun barrel 10 may comprise a bore 18 that is smooth, meaning that it does
not have any
grooves or ridges, known as rifling, that would assist in stabilization of the
projectile fired
therefrom. Smooth-bored gun barrels are advantageous in that they are less
expensive to
make, and because in a smooth gun barrel the projectile is under less force,
the barrel itself is
under less stress than a gun barrel with a rifled bore. Therefore, a smooth-
bored gun barrel
may have a longer usable life. However, alternative embodiments of the gun
barrel may
include bores 18 in which there is rifling. A projectile may be more
accurately launched
through a rifled bore than a smooth bore. Therefore, a rifled bore may be used
for
applications where accuracy is important. However, the use of a fin-stabilized
projectile in a
smooth bored gun barrel 10 would likely provide sufficient accuracy for most
purposes.
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The compressible material used in the gun barrel is a material that has a
compressive strength
sufficiently high to enable the layer of material to substantially withstand
the compressive
load that it may be subjected to during the firing of a projectile from a gun
barrel.
"Compressive strength" is a reference to the ability of a material to
withstand compressive
(squeezing) loads without being crushed when the material is in compression.
The
compressible material may have a compressive strength that is less or greater
than the
compressive strength of either or both of the inner support layer and outer
support layer of the
gun barrel in which it is used.
In one embodiment the compressible material 16 is concrete. "Concrete" as used
herein
means an aggregation of minerals, such as sand, that has been coalesced into a
solid mass
with cement and water. "Cement" as used herein refers to the binding material
in concrete.
Concrete with a compressive strength above 10 mPa may be used and concrete
with a
compressive strength of about 80 mPa is preferred.
Other compressible materials that have a compressive strength of about at
least 10 mPa would
be useful in the gun barrel. Of particular use may be plastics, or other
synthetic materials that
have a compressive strength that is as high or higher than concrete, but which
would be
significantly lighter than concrete.
The thickness of the layer of the compressible material 16 will vary,
depending upon the other
features of the gun barrel 10. For example, if thicker support layers 12 and
14 are used, the
layer of compressible material may be thinner than in a gun barrel of the same
dimensions but
with thinner support layers 12 and 14.
The use of concrete in the gun barrel 10 that has the inner and outer support
layers 12 and 14
made of steel, may reduce the weight and cost of the gun barrel as compared to
a steel gun
barrel of the same dimensions, while providing a gun barrel sufficiently
strong for firing
projectiles. Other inexpensive compressible materials as defined herein, used
in the gun
barrel 10 that has the inner and outer support layers 12 and 14 made of steel,
would also be
useful to make a lighter and less expensive gun barrel than one made entirely
out of steel, but
which would be sufficiently strong for the firing of large projectiles.
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The layer of compressible material in any of the embodiments disclosed herein
may be
reinforced by a reinforcing element 30. The reinforcing element 30 may
increase the strength
and stability of the compressible material 16, and thereby reduce or eliminate
the possibility
that the layer of material will crack, or otherwise break up when the
projectile 20 is fired from
5 the gun barrel 10. In the embodiment shown in Figure 2, the reinforcing
element 30 is
comprised of a steel concrete reinforcing bar known as rebar and the
compressible material is
concrete. The size and type of rebar used, including diameter and length, will
vary according
to the dimensions of the gun barrel. As can be seen in Figure 2, the rebar is
positioned
longitudinally, with respect to the longitudinal axis of the gun barrel 10,
within compressible
10 material 16, and held in place with the assistance of wire, 31. Wire mesh
is another common
reinforcing element 30 used in concrete. Additionally, chemicals that
strengthen concrete,
such as flyash, may be used as a reinforcing element. When concrete is used,
reinforcement
with rebar or wire mesh is preferred in most circumstances.
Figure 3 shows an embodiment 110 which comprises an outer support layer 112,
an inner
support layer 114, and disposed there between, a layer of compressible
material 116. Layers
112, 114 and 116 have the same characteristics as described above for layers
12, 14 and 16.
The inner support layer 114 defines a bore 118 along which a projectile will
travel, from a
breech end 122 to a muzzle end 124. Bore 118 decreases in diameter from breech
end 122 to
muzzle end 124, having two transition regions 125, the length of which are
represented by
arrows 128 and 134. Therefore, bore 118 comprises three sections of different
diameter,
referred to herein as the wide-, mid- and narrow-diameter bore regions, with a
length as
represented by arrows 126, 132 and 136. The transition regions connect the
various sections
of the bore. Preferably the transition regions will be angled at about 2-20
degrees from the
longitudinal axis of the bore, however the angle may be greater or less,
provided that it does
not adversely interfere with the movement of the projectile along the bore
118.
Unlike the embodiment shown in Figure 1, the outer diameter of the gun barrel
110 decreases
at a point 140 along the length of the gun barrel 110.
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The thickness of the layer of compressible material 116 varies along the
length of the gun
barrel 110. In region 138 of Figure 3, the outer diameter of the gun barrel is
constant,
whereas the diameter of bore 118 varies. Therefore, the thickness of the layer
of compressible
material 116 will vary accordingly. After the transition at point 140 from a
wider to a
narrower outer diameter, while the diameter of the bore remains constant, the
thickness of the
layer of compressible material 116 will again change.
Figure 4 shows an alternative embodiment 210 which comprises an outer support
layer 212,
an inner support layer 214, and disposed therebetween, a layer of compressible
material 216.
Layers 212, 214 and 216 have the same characteristics as described above for
layers 12, 14
and 16. The inner support layer 214 defines a bore 218, along which a
projectile will travel
from a breech end 222 to a muzzle end 224. Bore 218 decreases in diameter from
breech end
222 to muzzle end 224, having two transition regions 225 the length of which
are represented
by arrows 228 and 234, which result in a bore that comprises three sections of
different
diameter. These three sections are referred to herein as the wide-, mid- and
narrow-diameter
bore regions, the length of which are represented by arrows 226, 232 and 236,
respectively.
The transition regions connect the various sections of the bore.
Unlike the embodiment shown in Figure 3, the outer diameter of the gun barrel
210 decreases
at a point 240 along the length of the gun barrel 210, and again at point 250
along the length
of gun barre1210.
The thickness of the layer of compressible material 216 varies in the
embodiment shown in
Figure 4, to a greater extent than in the embodiment shown in Figure 3. In
region 238 of
Figure 4, the outer diameter of the gun barrel is constant, whereas the
diameter of bore 218
varies. Therefore, the thickness of the layer of compressible material 216
will vary
accordingly. After the transition, at point 240 from a wider to a narrower
outer diameter,
while the diameter of the bore remains constant, the thickness of the layer of
compressible
material 216 will again change. After the transition, at point 250 to an even
narrower outer
diameter, while the diameter of the bore remains constant, the thickness of
the layer of
compressible materia1216 will again change.
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In the embodiments shown in Figures 3 and 4, an increasingly thinner layer of
compressible
material 116 or 216 is used in the sections of the gun barrel that are the
closest to the muzzle
end 124 or 224 or, farthest from the breech end 122 or 222. The layer of
compressible
material need not be as thick near the muzzle, as the forces in the gun barrel
are low at this
section of the barrel relative to the breech. Therefore, the gun barrels shown
in Figures 3 and
4 are lighter than the embodiments shown in Figure 1 and 5, if of the same
length.
Note as well that in the embodiments shown in both Figures 3 and 4, the
thickness of the
compressible material 16 is greatest nearer the breech end 122 or 222, as the
case may be,
which is where the greatest explosive forces will be experienced when a
projectile is fired
from the gun barrel.
The gun barrel 10 may be assembled by putting sections of pipe together. For
example,
sections of steel pipe with flanges at each end may be connected together as
by bolting, to
form the inner layer 14, which defines bore 18. Larger-diameter sections of
steel pipe, again
with flanges at each end, may be slipped over the inner support layer 12 and
connected
together for example by bolting. Alternatively, the sections of pipe may be
threaded together.
Alternatively, or in addition, metal glues may be used to hold the sections of
pipe together. In
this method of manufacturing the gun barrel, the joints of the inner and outer
support layers
may not be at the same positions along the finished gun barrel. Reinforcing
materials, such as
rebar and wire mesh may be placed between the two assembled support layers,
followed by
addition of the layer of compressible material 16, for example concrete, which
would be
poured in between the inner and outer support layers. To the breech end of the
gun may be
welded a metal plate, either at the end of the bore (at the end of the inner
support), at the end
of the outer support, or at both, an example of which is shown in Figure 7. In
the breech end,
between the inner and outer support layers may also be placed a stabilizer 19.
These methods
of manufacturing the gun barrel are intended to demonstrate ways that the gun
barrel may be
made, and are not intended to be limiting.
In an alternative embodiment 410 of the gun barrel, shown in Figure 6, the
breech portion of
the gun barrel is made entirely out of a metal, for example, steel or
titanium. The breech
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portion 450 is connected as by bolting or threading, to the remainder of the
gun barrel, that is
made as disclosed above. This hybrid gun barrel 410 shown in Figure 6, would
have a breech
portion 450 comprised entirely of metal and the remainder would be comprised
of an inner
support layer 414, an outer support layer 412 and a layer of compressible
material 416
disposed therebetween, and as disclosed above. The breech portion 450 is
connected to the
rest of the gun barrel as by bolts that are threaded through flanges 452. The
hybrid gun barrel
410 would have the advantage of having a very strong breech, where the
explosive forces
from the propellant are the greatest, with the remainder of the gun barrel
being relatively
inexpensive and lightweight by comparison, but strong enough to withstand the
forces
generated by the propellant in this part of the gun barrel 410, which is
distant from the breech.
The breech portion will preferably comprise a portion of the bore 418, as
shown in Figure 6.
Having thus described the gun barrel, methods of using the gun barrel 10 to
launch a rocket
comprising a satellite payload will now be disclosed. The gun barrel will
launch a rocket with
a satellite payload to a position beyond the lower atmosphere. "Lower
atmosphere" as used
herein generally refers to the pai-t of the atmosphere in which most weather
phenomena occur,
(i.e. the troposphere and the stratosphere), and where the majority of the
drag on the projectile
will occur. Generally, the lower atmosphere will encompass about the first 12
km of the
atmosphere above the surface of the earth. Once past the lower atmosphere, the
rocket will be
fired in two or more additional stages, in order to achieve orbital velocity.
The gun barrel can
be used to assist in the launching of satellites into an orbital path that is
at an altitude of about
100-300 miles above the earth's surface, generally known in the art as a "low
earth orbit". To
enter a circular orbit at an altitude of 100 km a velocity of 7.8 km/sec is
required and to enter
a elliptical orbit a velocity of 10 km/sec is required. In the latter case,
orbit will preferably be
entered at perigee, as this is the simplest and most fuel-efficient way to
enter orbit.
The gun barrel will launch a projectile, such as a rocket with a satellite and
sabot, at a muzzle
velocity sufficient to launch the projectile beyond the lower atmosphere.
Depending upon a
number of parameters, including the weight and shape of the projectile, the
length of the gun,
the amount of propellant used, the muzzle velocity of a projectile launched
from the gun
barrel will be above 1,350 m/sec, and preferably about 1,350 to 3,000 m/sec.
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The propellant used to launch the projectile from the gun barrel is preferably
be a solid
propellant, for example M8M propellant, or a composite propellant. The weight
of the
projectile is likely to be between about 1,100 - 1,600 kg, however it can be
more or less.
The rocket to be used in the method may be a conventional rocket that can be
obtained for
example from military sources. The use of polyurethane foam or a mixture of
epoxy and sand
protects the electronic components of the rocket and satellite from shock and
blast waves.
The shape and design of the projectile that is launched from gun barrel are
key factors in the
ability of the gun barrel to assist with the launch of a satellite into orbit.
The rocket will
preferably have a slender lengthened nose cone to decrease drag, and
preferably will use a
base bleeder design. The base bleeder design reduces base drag, which is
caused by a vacuum
or suction effect at the base of the projectile. If the rocket is fired from a
smooth bore gun
barrel, the rocket will likely be fin stabilized. However, other means of
stabilizing the rocket
during flight are intended to be included herein.
Preferred in the methods disclosed herein is a rocket that uses liquid, rather
than solid
propellant. Solid propellants in a rocket cannot generally withstand the blast
forces of the
launch from the gun barrel, although plastic solid rocket fuels may be able to
do so. If the
fuel cell in the rocket is completely full of liquid propellant, the fuel cell
will be able to
withstand the G-forces of launch. Additionally, fuel cells for liquid
propellants can have
thinner walls than can fuel cells for solid propellants, making the entire
rocket lighter. Solid
fuels may also be used in the rocket, and provide the advantage of being able
to be activated
by a time-delayed fuse, such as a squib.
Liquid fuels provide about 2-times the thrust of solid fuels, liquid fuels can
be throttled, and
they have a superior specific impulse. The latter is defined as the thrust
developed by burning
one pound of fuel in one second, and therefore specific impulse is the inverse
of fuel
efficiency. By using a more efficient fuel, the rocket is lighter. A preferred
liquid fuel is
kerosene, although other fuels may be used. A liquid fuel is used with an
oxidant. Preferred
as an oxidant is hydrogen peroxide, although liquid oxygen may be used as
well.
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Particularly preferred is a rocket that uses hydrogen peroxide as propellant,
kerosene as
oxidant, and which has a specific impulse of at least 200. A specific impulse
of over 200 is
required to achieve orbital velocity. This rocket is able to carry more
propellant for its size
than other rockets. This rocket can be obtained commercially, or can be
manufactured from
5 stainless steel by a skilled machinist
The methods include the use of a sabot, which as used herein means a device
fitted around or
in back of the rocket in a gun barrel. The sabot may be made of any of a
number of materials,
including metal and wood. The sabot performs one or more of a variety of
functions
including: supporting the projectile, protecting the projectile, preventing
the escape of gas
10 ahead of the sabot, and increasing the life-span of the gun barrel. The use
of a sabot increases
the muzzle velocity and range of the rocket. Also, as a sabot can be
positioned around the
rocket, the diameter of the bore that can be used is increased, with a
corresponding increase in
the amount of propellant that can be used in the barrel. The sabot separates
from the rocket,
after launching, and in this regard, a sabot stripper may be added at or near
the muzzle of the
15 gun barrel to aid in the removal of the sabot upon exit of the projectile
from the barrel.
The muzzle end 24 of the gun barrel 10 may have a cap placed over its opening,
said cap
popping off of the muzzle end just before the projectile reaches the muzzle.
The cap causes a
vacuum to be created in the gun barrel, which vacuum permits the projectile to
travel
significantly further than without it.
To decrease the amount of air resistance (drag) experienced by the projectile
after launch, the
gun barrel may be positioned at a high altitude, for example on the top of a
mountain. If
positioned at a 45-degree angle before launching the projectile, for example
by resting it on
the side of a hill, and launched eastward, the rocket will be boosted by the
earth's rotation.
The gun barrel may be used to launch projectiles in other applications, for
example in fire-
fighting (e.g., forest fires, high-rise building, industrial fires)
applications. In this case the
gun barrel may be a mortar. One way to make this mortar is to weld a metal
base onto a
section of pipe and place it within a larger-diameter outer pipe that also has
a base welded
onto it. Concrete with or without reinforcement, such as rebar and wire mesh,
may be
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disposed between the inner pipe base and the outer pipe on all sides and at
the breech end. A
stabilizer may be added to assist with the assembly of the barrel.
Several methods may be used to launch a projectile from this gun barrel, which
projectile may
comprise water, fire-retardant (e.g., foam), dry chemicals (e.g., Purple K),
neutralizing agents
(e.g., ammonia). In forest fire applications the projectile may even comprise
tools or supplies
that are being launched into a forest fire staging area, or incendiary shells
that create a fire
break. The projectile may have a cardboard sabo and a plywood pusher plate to
protect the
container from the propellant. A cylindrical, spherical, or otherwise-shaped
projectile may be
used.
A cylindrical projectile has a tendency to tumble when fired from a smooth
bore mortar. Fins
or streamers may be used to stabilize the projectile and to provide for
reasonable accuracy. A
wind-screen may also be placed on the front of the projectile to make it more
aerodynamic,
which may increase range and accuracy.
A black powder or a variety of artillery propellants or chemical systems may
be used to eject
the projectile. It is also possible to use flammable gas or liquids in a
deflagration/detonation.
Examples are propane, methane, hydrogen or any other gas that, when mixed with
air or an
oxidizer would create a deflagration/detonation. Useful liquid propellants
include butane,
automobile gas, ether and WD-40. Compressed air, stored in a high pressure
breech may also
be used.
An explosive device inside the projectile may detonate the projectile over the
fire target. The
device may be triggered by remote control, heat sensor, time fuses (clock or
lit fuse) and/or
trailing wire. Or, chemicals that expel gas over time and cause the cylinder
to rupture, for
example dry ice, sodium bicarbonate/vinegar or battery acid/sodium
bicarbonate, may be
used.
While the invention has been described in conjunction with the disclosed
embodiments, it will
be understood that the invention is not intended to be limited to these
embodiments. On the
contrary, the invention is intended to cover alternatives, modifications and
equivalents, which
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may be included within the spirit and scope of the invention as defined by the
appended
claims. In particular, any gun barrel that uses the principle of this
invention, which is that of
layering a compressible material between two layers of a support material, is
intended to be
included herein.
The following examples are intended only to illustrate and describe the
invention rather than
limit the claims that follow.
EXAMPLES
Example 1:
To fire a projectile, such as a rocket with sabot, that is a total weight of
about 10.5 kg; a gun
barrel of about 9.1 meters in length can be used. The gun barrel would have a
constant outer
diameter of about 25 cm. The inner bore would comprise two sections with
different
diameters, a wide-diameter section and a narrow-diameter section. The wide-
diameter
section, closer to the breech end, would be about 0.9 meters in length, and
would have a
constant diameter of about 15 cm. The narrow-diameter section, nearer the
muzzle end,
would be about 7.9 meters in length, and would have a constant diameter of
about 13 cm. A
30.5 cm long transition section, of varying diameter, would connect these two
sections of the
bore.
The outer layer would be comprised of 12.5 mm thick, A105 steel, and the inner
layer would
be made of 12.5 mm thick, A105 steel. The concrete layer formed between the
two steel
layers would be concrete with a compressive strength of 80 mPa, reinforced
with #10 rebar.
The thickness of the concrete layer varies from breech to muzzle, as the inner
bore is wider
closer to the breech end and narrower closer to the muzzle end, whereas the
outer diameter of
the gun barrel remains constant. Around the wide-diameter section of the bore,
the concrete
layer would be about 2.5 cm wide, whereas around the narrow-diameter section
of the bore,
the concrete layer would be about 3.8 cm wide.
This gun barrel is calculated to be stable to a maximum breech pressure of
about 80,000 psi,
but would be used at a working pressure of about 50,000 psi. The projectile
would be
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discharged with 50 pounds of M8M propellant, resulting in a muzzle velocity of
about 1,650
m/sec.
Example 2:
To fire a projectile that is a total weight of about 2,500 kg including the
rocket, satellite and
sabot beyond the lower atmosphere, a gun barrel of about 98 meters in length
can be
constructed. The gun barrel would have two sections, each with a different
outer diameter,
referred to as wide- and narrow-diameter sections. The wide-diameter section,
nearer to the
breech end, would have a constant diameter of about 1550 mm, and the narrow-
diameter
section, nearer the muzzle end, would have a constant diameter of about 1100
mm. The wide-
diameter section would be a total of about 7 meters in length, whereas the
narrow-diameter
section would be a total of about 92 meters in length.
The bore would comprise three sections each with different diameters, namely,
wide-, mid-
and narrow-diameter section. The wide-diameter section, nearer the breech end,
would be
about three meters in length, and would have a constant diameter of about 1000
mm. The
mid-diameter section, next closest to the muzzle end, would be about two
meters in length,
and would have a constant diameter of about 900 mm. The narrow-diameter
section, closest
to the muzzle end, would be about 91 meters in length, and would have a
constant diameter of
about 800 mm. 30.5 cm long transition sections would connect sections of the
bore that vary
in diameter.
The outer support layer would be comprised of 12.5 mm thick, A105 steel, and
the inner
support layer would have a smooth bore and be comprised of 12.5 mm thick, A105
steel. The
first 20 meters of the inner bore would be comprised of hardened steel.
The concrete layer formed between the two steel layers is made from concrete
with a
compressive strength of 80 mPa and reinforced with #10 rebar. The thickness of
the concrete
layer varies proceeding from breech towards muzzle, within the first 7 meters
of the barrel.
Around the wide-diameter section of the bore, the concrete layer is about 250
mm thick;
around the mid-diameter section of the bore, the concrete layer is about 300
mm thick, and
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around the narrow diameter section of the bore, the concrete layer is about
350 mm thick.
After the first 7 meters, the outer diameter of the gun barrel decreases to
1100 mm and
therefore the thickness of the concrete layer decreases to about 125 mm.
The gun barrel would comprise a sabot stripper that removes the sabot
uniformly and does not
effect projectile stability in flight. Additionally, a vacuum cap on the gun
barrel will increase
range.
The projectile to be fired would have a diameter of about 800 mm and a length
of about 9
meters.
This gun barrel is calculated to be stable to a maximum breech pressure of
about 95,000 psi,
but would be used at a working pressure of about 65,000 psi. The projectile
would be
discharged with M8M propellant, resulting in a muzzle velocity of about 2,100
m/sec.
Example 3
To fire a projectile that is a total weight of about 2,500 kg, including the
rocket, satellite and
sabot, beyond the lower atmosphere, a gun barrel of about 125 meters in length
can be
constructed. The gun barrel would have sections with one of three different
outer diameters,
referred to as wide- mid- and narrow-diameter sections. The wide-diameter
section, nearer to
the breech end, would have a constant outer diameter of about 1550 mm, the mid-
diameter
section would have a constant outer diameter of about 1100 mm and the narrow-
diameter
section would have a constant outer diameter of about 900 mm. The wide-
diameter section
would be a total of about 22 meters in length, the mid-diameter section would
be a total of
about 12 meters in length, and the narrow-diameter section would be a total of
about 91
meters in length.
The bore would comprise three sections each with different diameters, namely,
wide-, mid-
and narrow-diameter section. The wide-diameter section, nearer the breech end,
would be
about 10 meters in length, and would have a constant diameter of about 1000
mm. The mid-
diameter section, next closest to the muzzle end, would be about 10 meters in
length, and
would have a constant diameter of about 900 mm. The narrow-diameter section,
closest to the
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muzzle end, would be about 91 meters in length, and would have a constant
diameter of about
800 mm. A one meter long transition section, of varying diameter, would
connect two
sections of the bore that are different in diameter.
The outer support layer would be comprised of 12.5 mm thick, A105 steel, and
the inner
5 support layer would have a smooth bore and be comprised of 12.5 mm thick,
A105 steel. The
first 25 meters of the bore will be comprised of hardened steel.
The concrete layer between the two steel layers is made from concrete with a
compressive
strength of 80 mPa and reinforced with #10 rebar. The thickness of the
concrete layer varies
proceeding from breech towards muzzle. Within the first 22 meters of the
barrel, around the
10 wide-diameter section of the bore, the concrete layer is about 250 mm
thick; around the mid-
diameter section of the bore, the concrete layer is about 300 mm thick, and
around the narrow
diameter section of the bore, the concrete layer is about 350 mm thick. After
the first 22
meters, the outer diameter of the gun barrel decreases to 1100 mm, and
therefore the thickness
of the concrete layer decreases to about 125 mm. After the next 12 meters,
proceeding
15 towards the muzzle end, the outer diameter of the gun barrel decreases to
900 mm and the
thickness of the concrete layer is about 25 mm.
The gun barrel would comprise a sabot stripper that removes the sabot
uniformly and does not
effect projectile stability in flight. Additionally, a vacuum cap on the gun
barrel will increase
range.
20 The projectile to be fired would have a diameter of about 800 mm and a
length of about nine
meters.
This gun barrel is calculated to be stable to a maximum breech pressure of
about 95,000 psi,
but would be used at a working pressure of about 60,000 psi. The projectile
would be
discharged with M8M propellant, resulting in a muzzle velocity of about 2,100
m/sec.
Example 4
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This gun barrel can be used to launch a projectile with a weight of about
1,100 kg and a
length of about 9 meters. The projectile to be launched would have a diameter
of about 800
mm, 400 mm of that diameter comprising the rocket, and 400 mm of that diameter
comprising
the sabot that surrounds the rocket. The sabot functions to protect the
rocket, to increase the
muzzle velocity and to increase the life of the gun. The projectile will be
fin stabilized.
The gun barrel would be a total of about 77 meters in length, with the first
32 meters of the
bore lined with hardened steel to increase the life of the gun. The bore would
have a constant
diameter of 800 mm, the concrete layer would have a thickness of about 260 mm,
and the
inner and outer support layers would be made of 12.5 mm thick, A105 steel.
Therefore, the
outer diameter of the gun barrel would be about 1370 mm. The concrete layer
formed
between the two steel layers is made from concrete with a compressive strength
of 80 mPa
and reinforced with #10 rebar.
The gun barrel would comprise a sabot stripper that removes the sabot
uniformly and does not
effect projectile stability in flight. Additionally, a vacuum cap on the gun
barrel will increase
range. Explosives lined up in front of the gun, and detonated just prior to
the projectile
leaving the gun will create a vacuum that may decrease drag.
The gun barrel would be positioned at a 45-degree angle before launching the
projectile, for
example by resting it on the side of a hill. The propelling charge would be
600 kg of M8M
propellant. It is anticipated that the muzzle velocity of the projectile would
be approximately
1,500 m/sec, which would be sufficient to launch the projectile past the first
12 km of the
atmosphere.
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