U.S. patent application number 13/680564 was filed with the patent office on 2014-05-22 for thrust-producing device with detonation motor.
This patent application is currently assigned to RAYTHEON COMPANY. The applicant listed for this patent is RAYTHEON COMPANY. Invention is credited to Gavin Buttigieg, Jeremy C. Danforth, Henri Y. Kim, Brian J. Lukow.
Application Number | 20140137539 13/680564 |
Document ID | / |
Family ID | 49517618 |
Filed Date | 2014-05-22 |
United States Patent
Application |
20140137539 |
Kind Code |
A1 |
Danforth; Jeremy C. ; et
al. |
May 22, 2014 |
THRUST-PRODUCING DEVICE WITH DETONATION MOTOR
Abstract
A detonation thrust-producing device includes an explosive
located in a recess in an external surface of a body. Detonation of
the explosive expels material out of the recess, providing thrust
to the body in an opposite direction. A mass, such as a metal disk,
may be placed blocking or covering the external opening. The body
may be a part of a vehicle, such as an airborne projectile. The
thrust-producing device may include multiple detonation motors
arrayed around the body, capable of being individually or multiply
detonated. Such thrust-producing devices may be used for attitude
adjustment, steering, or other control of the flight of the
projectile or other air vehicle. The detonation thrust-producing
devices have the advantage of a faster-response time than
propellant-based devices, and do not need the nozzles that are used
with many propellant-based devices.
Inventors: |
Danforth; Jeremy C.;
(Tucson, AZ) ; Buttigieg; Gavin; (Tucson, AZ)
; Lukow; Brian J.; (Tempe, AZ) ; Kim; Henri
Y.; (Tucson, AZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
RAYTHEON COMPANY; |
|
|
US |
|
|
Assignee: |
RAYTHEON COMPANY
Waltham
MA
|
Family ID: |
49517618 |
Appl. No.: |
13/680564 |
Filed: |
November 19, 2012 |
Current U.S.
Class: |
60/205 ;
60/200.1; 60/228 |
Current CPC
Class: |
F02K 9/08 20130101; F02K
7/02 20130101; F42B 3/04 20130101; F42B 10/661 20130101 |
Class at
Publication: |
60/205 ;
60/200.1; 60/228 |
International
Class: |
F42B 10/66 20060101
F42B010/66 |
Claims
1. A thrust-providing device comprising: a body; and a detonation
motor; wherein the detonation motor includes an explosive in a
recess in an external surface the body; and wherein detonation of
the explosive provides thrust to the body opposite to a direction
that material is expelled from the recess.
2. The thrust-producing device of claim 1, further comprising a
detonator operatively coupled to the explosive to detonate the
explosive.
3. The thrust-producing device of claim 2, wherein the detonator is
operatively coupled to a control system that controls triggering of
the detonator.
4. The thrust-producing device of claim 1, wherein the body has an
interior opening that puts the recess into communication with an
interior cavity of the body.
5. The thrust-producing device of claim 4, further comprising a
filler between the explosive and the opening.
6. The thrust-producing device of claim 5, wherein the filler
includes a potting compound.
7. The thrust-producing device of claim 1, further comprising a
projectile operatively coupled to the explosive, wherein the
projectile is expelled clear of the body when the explosive is
detonated.
8. The thrust-producing device of claim 7, wherein the explosive
weighs from 1 to 3 times what the projectile weighs.
9. The thrust-producing device of claim 7, wherein the projectile
is a disk.
10. The thrust-producing device of claim 7, wherein the projectile
is made of metal.
11. The thrust-producing device of claim 7, wherein the projectile
is in the recess.
12. The thrust-producing device of claim 1, wherein the recess has
a circular cross-section shape.
13. The thrust-producing device of claim 1, wherein the detonation
motor is one of a multitude of detonation motors that are part of
the thrust-producing device.
14. The thrust-producing device of claim 13, wherein the
thrust-producing device is part of an aircraft; and wherein the
thrust-producing device is used to steer the aircraft.
15. The thrust-producing device of claim 14, wherein the body of
the thrust-producing device is part of an external surface of the
aircraft.
16. The thrust-producing device of claim 14, wherein the detonation
motors are circumferentially spread around a perimeter of the
aircraft.
17. An aircraft comprising: a body; and detonation motors
circumferentially spread around a perimeter of the body; wherein
each of the detonation motors includes an explosive in a recess in
an external surface the body, wherein detonation of the explosive
provides thrust to the body opposite to a direction that products
from the detonation are expelled from the recess.
18. A method of steering an object, the method comprising:
detonating an explosive in a recess in a body of the object; and
expelling gasses generated by the explosive from the recess,
thereby creating thrust on the object.
19. The method of claim 18, wherein the expelling gasses includes
expelling a solid projectile using the gasses.
20. The method of claim 18, wherein the object is an aircraft, and
the creating thrust is used for steering the object.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention is in the field of thrust-producing
devices.
[0003] 2. Description of the Related Art
[0004] Many sorts of devices are used for producing thrust for a
variety of purposes. Traditional rocket motors use sustained
combustion of solid or liquid propellants in combination with a
supersonic nozzle to accelerate the exhaust products to high
velocities, creating a reaction force. However such rocket motors
are not suitable for providing reaction forces over very short
timeframes.
SUMMARY OF THE INVENTION
[0005] A thrust-producing device uses one or more detonation motors
with explosives, to generate thrust over very short timeframes.
[0006] According to an aspect of the invention, a thrust-providing
device includes: a body; and a detonation motor. The detonation
motor includes an explosive in a recess in an external surface of
the body. Detonation of the explosive provides thrust to the body
opposite to the direction that material is expelled from the
recess, through an external opening in the body.
[0007] According to another aspect of the invention, an aircraft
includes: a body; and detonation motors circumferentially spread
around a perimeter of the body. Each of the detonation motors
includes an explosive in a recess in an external surface the body,
wherein detonation of the explosive provides thrust to the body
opposite to a direction that material is expelled from the recess,
through an external opening in the body.
[0008] According to yet another aspect of the invention, a method
of steering an object includes the steps of: detonating an
explosive in a recess in a body of the object; and expelling gasses
generated by the explosive, thereby creating thrust on the
object.
[0009] To the accomplishment of the foregoing and related ends, the
invention comprises the features hereinafter fully described and
particularly pointed out in the claims. The following description
and the annexed drawings set forth in detail certain illustrative
embodiments of the invention. These embodiments are indicative,
however, of but a few of the various ways in which the principles
of the invention may be employed. Other objects, advantages and
novel features of the invention will become apparent from the
following detailed description of the invention when considered in
conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The annexed drawings, which are not necessarily to scale,
show various aspects of the invention.
[0011] FIG. 1 is an oblique view of a thrust-producing device in
accordance with an embodiment of the invention, as part of an
aircraft.
[0012] FIG. 2 is a cross-sectional fragmentary view of part of the
device of FIG. 1, showing details of a detonation motor of the
device.
[0013] FIG. 3 is an oblique view of the device of FIG. 1, showing a
first step in a method of using the device to change course.
[0014] FIG. 4 is an oblique view illustrating a second step of the
method.
[0015] FIG. 5 is an oblique view illustrating a third step of the
method.
[0016] FIG. 6 is a cross-sectional fragmentary view, showing
details of an alternate embodiment detonation motor.
[0017] FIG. 7 is a view of a device in accordance with another
alternate embodiment of the present invention.
DETAILED DESCRIPTION
[0018] A detonation thrust-producing device includes an explosive
located in a recess in an external surface of a body. Detonation of
the explosive expels material out of the recess, providing thrust
to the body in an opposite direction. A mass, such as a metal disk,
may be placed blocking or covering the external opening, such as in
the recess between the explosive and the external opening. The body
may be a part of a vehicle, such as an airborne projectile. The
thrust-producing device may include multiple detonation motors
arrayed around the body, capable of being individually or multiply
detonated to provide thrust to the body in different amounts and/or
in different directions. Such thrust-producing devices may be used
for attitude adjustment, steering, or other control of the flight
of the projectile or other air vehicle. The detonation
thrust-producing devices have the advantage of a faster-response
time than propellant-based devices, and do not need the nozzles
that are used with many propellant-based devices.
[0019] FIG. 1 shows a detonation thrust-producing device 10 that is
part of an airborne vehicle or aircraft 12 (intended to broadly
include all types of flying things or devices, including space
vehicles), such as a projectile or missile. The device 10 may be
used to steer the aircraft 12, producing small bursts of thrust
from detonation motors 14 around the perimeter or circumference of
a body 16 of the aircraft 12. The small bursts of thrust may be
produced in any of various directions to cause a corresponding
reaction in the aircraft 12. As described in greater detail below,
small explosive devices in the detonation motors 14 are ignited to
produce the bursts of thrust.
[0020] The thrust-producing device 10 may have detonation motors 14
able to provide thrust in any of a variety of directions. The
detonation motors 14 may be circumferentially spread around a
perimeter of the body 16, and/or there may be multiple rows of
detonation motors 14 at the same circumferential locations,
separated in a direction of a longitudinal axis 20 of the device
10. The device longitudinal axis 20 may also be the longitudinal
axis of the aircraft 12, as in the illustrated embodiment. The
detonation motors 14 may be arrayed in a limited number of
circumferential locations about the perimeter of the body 16. For
example, the detonation motors 14 may be at four circumferential
locations equally spaced about the perimeter of the body 16, or
eight equally-space locations, or any other number of suitable
locations of suitable spacing.
[0021] The detonation motors 14 are coupled to a controller 24 that
controls selective activation of the detonation motors 14. The
controller 24 may detonate one or more of the detonation motors 14
as needed, to provide thrust to change the course and/or
orientation of the aircraft 12. The controller 24 may be used to
activate detonation motors 14 to provide thrust in a desired
direction, and may control the number of detonation motors 14
activated in order to control the level of thrust provided. The
controller 24 may include integrated circuits or other suitable
devices, to be used in making a determination or otherwise
controlling activation of the detonation motors 14. The controller
24 may be in communication to other devices external to the
aircraft 12, such as ground stations or aircraft that fire or
simply control the aircraft 12, to receive signals regarding
movements of a target to be intercepted by the aircraft 12, or
another desired location to be achieved by the aircraft 12.
[0022] One possible use of the thrust-producing device 10 is in
altering course of the aircraft 12 to intercept a moving target,
such as an incoming projectile. For such a purpose rapid course
correction is greatly desired, since little time may be available
for correcting course in order to intercept the incoming
projectile.
[0023] Other uses are possible for the thrust-producing device 10.
It may be used on any of a variety of aircraft for any of a variety
of purposes. The thrust-producing device 10 may also be used on
other sorts of devices, for a variety of purposes. Examples of
other such devices include satellites and torpedoes. Instead of
having detonation motors 14 with different orientations, as an
alternative all of the detonation motors 14 (or even a single
detonation motor 14 that is the only detonation motor, in another
embodiment of the device 10) may provide thrust in only a single
direction. An example of such an embodiment is in a small missile
or munition, which may involve control over thrust in a single
axis, for example as a means of throttling. Instead of smoothly or
continuously modulating thrust of a motor, a thrust-producing
device can produce small increments of thrust.
[0024] Turning now to FIG. 2, details are shown of one of the
detonation motors 14. The detonation motor 14 includes an explosive
32 that is located in a recess 34 in the body 16. In the
illustrated embodiment the recess 34 is a cylindrical recess, with
a circular cross section shape, and oriented substantially
perpendicular to an outer surface 35 of the body 16. Alternatively
the recess 34 may have any of a variety of other shapes and/or
orientations.
[0025] The recess 34 has an external opening 36 where it is open to
a region 38 external to the body 16. The recess 34 also may have an
internal opening 42 that puts the recess 34 into communication with
an interior cavity 34 that is enclosed by the body 14. The internal
opening 42 may allow access from the bottom of the recess 34 to a
detonator 44 that is used to detonate the explosive 32. The
internal opening 42 is blocked by a filler 48 that is in a bottom
portion of the recess 34, in order to prevent egress from the
internal opening 42 of pressurized gasses or other products of the
detonation of the explosive 32. The filler 48 may be a suitable
potting material.
[0026] A casing 50 surrounds explosive 32 and the filler 48. The
casing 50 holds the explosive 32 and the filler 48 in place and
aligned. The casing 50 may be made of suitable metal, for example
being made of bronze gilding metal, or aluminum.
[0027] The detonator 44 may have wires 52 or other communication
devices for connection to the controller 24 (FIG. 1). The wires 52
may pass through the internal opening 42. Alternatively the
controller 24 may communicate with the detonator using various
other sorts of communication methods, for example using fiber optic
cables or wireless communication methods, such as the sending and
receiving of suitable radio frequency (RF) signals.
[0028] The external opening 36 may also be blocked or covered,
preventing direct communication between the explosive 32 and the
external region 38. In the illustrated embodiment this is
accomplished by a projectile or mass 58 that is in a part of the
recess 34 that is closest to the external opening 36. Alternatively
the projectile 58 may be outside of the recess 34, covering the
external opening 36. Detonation of the explosive 32 expels the
projectile or mass 58 clear of the body 16, into the surrounding
region 38.
[0029] The use of the projectile mass 58 may aid in maximizing
thrust output from the detonation motor 14. The projectile 58 may
have a mass that is about half the mass of the explosive 32. More
broadly, the projectile 58 may have a mass that is from 0.1 to 2
times the mass of the explosive charge 32, although other ratios
are possible. Such a charge mass (explosive) may provide a specific
impulse (thrust integral divided by propellant mass) of at least
175 seconds, with projectile/explosive mass ratio of about 0.5
providing a specific impulse of 220 seconds. It is possible that
higher projectile/explosive mass ratios may be used, producing a
lower specific impulse, where volume efficiency considerations are
important.
[0030] The projectile 58 may be made of any of a variety of
suitable materials, such as metal or plastic, and may have any of a
variety of characteristics, such as being solid or being pressed
powder. The projectile 58 may have a disk shape, or another shape
with a circular cross section, to fit the circular-cross-section
recess 34. Alternatively the projectile 58 may have a different
cross-section shape, particularly one that corresponds to a
non-circular-cross-shape of an alternative recess.
[0031] Advantageously, there may be no need for any sort of sealing
between the projectile 58 and the walls of the recess 34. The
explosive 32 detonates, as opposed to burning, so it generates
pressurized gasses very quickly, for instance in 10% or less of the
time to burn a corresponding amount of propellant.
[0032] The detonation motor 14, with its explosive 32, provides
many other advantages over propellant-based thrusters. Explosives
detonate, in contrast to the burning that occurs in propellants.
Burning of a solid propellant is governed by chemical kinetics and
reaction rates. These kinetics are specific to the propellant
formulation being used. The gas generated by burning of a solid
propellant is then generally accelerated through a nozzle to
supersonic exit velocities. Since the momentum thrust generated by
a propellant-based thruster is equal to the mass flow rate times
the velocity, the higher the velocity, the higher the thrust
generated by a given mass flow. Therefore a nozzle is an important
part of a propellant-based thruster. Dispensing with the nozzle in
a propellant-based thruster significantly reduces performance,
since the velocity is significant lower if there is no nozzle
present.
[0033] In contrast operation of the detonation motor 14 involves
detonation of the explosive 32. Detonation is not burning, but
instead is a reaction that propagates through an explosive
material, such as the explosive 32, at the speed of sound for the
medium. When the explosive 32 is detonated, it provides enough
momentum for the pressurized gasses to be expelled from the recess
34 at a velocity at least that of a traditional rocket motor (the
propellant-based nozzle-using thruster described above), but with
the advantage that no nozzle is needed. Being able to achieve good
performance without a nozzle means a smaller, lighter, and less
expensive thruster motor.
[0034] In addition, explosives that are detonated have higher
densities than solid rocket motor propellants. This results in the
detonation motor 14 having a higher volumetric efficiency than an
equivalent propellant-based thruster. The detonation motor 14 also
has the advantage of greater impulse per unit volume. For instance,
density specific impulse may be greater than a factor of two or
more using the detonation motor 14. Typical propellants have a
density specific impulse of about 400 g-sec/cc, while in an
embodiment of the detonation motor 14, the density specific impulse
was over 1800 g-sec/cc.
[0035] Detonations occur at least one order of magnitude faster
than even fast-acting thrusters that use solid propellants. For
example the detonation motor 14 can act in microseconds, as opposed
to seconds. This faster action allows for finer control, and
smaller impulse quanta. For example, 100 detonation micro-thrusters
can be activated in the time it takes to fire 10 traditional
solid-propellant-based thrusters. The firing of multiple
micro-thrusters may be sequential, rather than simultaneous, due to
the amount of energy required to fire multiple thrusters. A firing
circuit used to file multiple thrusters may need time to recharge
between firings of individual or groups of thrusters.
[0036] The explosive material for the explosive 32 may be any of a
variety of suitable explosives. Examples of suitable explosive
materials include CL-20, DBX-1, HNS-IV, and lead styphnate. Other
high explosive materials, such as RDX, HMX, TATB, LX-14, LX-17,
LX-19, or PBXN explosives, may also be used.
[0037] As noted, the filler 48 may be a suitable potting compound.
Examples of suitable potting compounds are epoxies and glasses.
[0038] FIGS. 3-5 show the thrust-producing device 10 in operation.
FIG. 3 shows the aircraft 12 traveling a first direction 70. In
FIG. 4 several of the detonation motors 14 on one side of the
thrust-producing device 10 are fired, expelling pressurized gasses
and their projectile 58 in the region around the aircraft 12. This
produces a reaction force 74 on the aircraft 12, which changes the
course of the aircraft 12 to the direction 78 shown in FIG. 5.
[0039] The aircraft 12 may have other common structures, some of
which may also be used for maintaining or changing course. For
example the aircraft 12 may include any or all of wings (or other
lift-producing devices), canards, ailerons, rudder(s), elevators,
and elevons. The aircraft 12 may include a propulsion system, such
as rocket motor, jet engine, or other thrust-producing device.
Alternatively the aircraft may be unpowered.
[0040] FIG. 6 shows an alternate embodiment thrust-producing device
110, which has a detonation motor 114. The detonation motor 114 is
in a recess 134 in a body 112. The recess 134 is packed with an
explosive 132 that is free, when detonated, to expel pressurized
gasses substantially unhindered through an external opening 136 to
an external region 138 that is outside of the body 112. In contrast
to the detonation motor 14 shown in FIG. 2, the detonation motor
114 does not have anything corresponding to the projectile 58 (FIG.
2) of the detonation motor 14. The detonation motor 114, when
compared with the detonation motor 14, has less weight and fewer
parts, and does not expel any solid items when detonated. However,
the detonation motor 114 may not perform as well (e.g., produce as
much thrust) as the detonation motor 14.
[0041] FIG. 7 shows still another embodiment, a spherical device
210 that has a series of detonation motors 214 placed around its
surface. The device 210 is "spherical" in the sense that it has a
generally round shape, which may have facets, such as circular or
polyhedral flat portions. The detonation motors 214 are located all
along the surface of the spherical device 214, and may be
symmetrically spaced about the spherical surface.
[0042] The detonation motors 214 may have the characteristics of
the detonation motors 14 and 114 (FIGS. 1 and 5, respectively)
described above. The detonation motors 214 may be able to provide
thrust to steer the device 210 in any of a wide variety of
directions.
[0043] The device 210 may have any of a variety of suitable sizes,
and may be used for accomplishing any of a variety of goals. In one
embodiment, the spherical device 214 may be a throwable object, for
example about the size of a softball or large hand grenade, which
could be maneuvered after throwing toward a target. For example the
device 210 may be a thrown munition that could be maneuvered around
a corner, while in flight, by firing appropriate of the detonation
motors 214. Suitable communication and control systems could be
used to guide the device 210 in this way.
[0044] The above description only discusses a few of the possible
configurations and potential uses of the thrust-producing devices
and detonation motors described. Many other variations are
possible.
[0045] Although the invention has been shown and described with
respect to a certain preferred embodiment or embodiments, it is
obvious that equivalent alterations and modifications will occur to
others skilled in the art upon the reading and understanding of
this specification and the annexed drawings. In particular regard
to the various functions performed by the above described elements
(components, assemblies, devices, compositions, etc.), the terms
(including a reference to a "means") used to describe such elements
are intended to correspond, unless otherwise indicated, to any
element which performs the specified function of the described
element (i.e., that is functionally equivalent), even though not
structurally equivalent to the disclosed structure which performs
the function in the herein illustrated exemplary embodiment or
embodiments of the invention. In addition, while a particular
feature of the invention may have been described above with respect
to only one or more of several illustrated embodiments, such
feature may be combined with one or more other features of the
other embodiments, as may be desired and advantageous for any given
or particular application.
* * * * *