Note: Descriptions are shown in the official language in which they were submitted.
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PROPULSION AND STEERING SYSTEM FOR AN AIRSHIP
FIELD OF THE INVENTION
[00011 The present invention relates generally to airships and more precisely,
to a propulsion
and steering system for an airship.
BACKGROUND OF THE INVENTION
[00021 Airships were, at one time, the preferred mode of aerial
transportation. Originally,
airships were steered using rudders similar to rudders of planes. A rudder
controls the yaw -
rotation about a vertical axis - of the airship by creating sideward lift when
traveling through air
at a relatively high speed. However, rudders are mostly inefficient at low
speeds. This tends to
pose a number of problems, notably at landing. For an airship to be able to
land at a precise
landing site, a substantial ground crew is usually required to ease the
airship towards the landing
site using ropes tethered to the airship. This problem is further exacerbated
when the landing is
to be performed in a limited space.
[00031 There are additional circumstances where precise positioning control of
the airship may
be important, for example, when loading or unloading good while hovering, when
conducting a
geophysical surveys or when the airship is used in search and rescue
applications. Conventional
airship steering systems tend not to be well-suited for the precisely
positioning the airship in
these types of applications.
[00041 A number of solutions to this problem have been suggested. For
instance, Canadian
Patent Application No. 2,631,277 of Colting discloses a steering apparatus for
an airship which
is provided with a plurality of ducts attached to the hull of an airship. Each
duct is defined by a
sidewall and houses an engine assembly operable to drive a propeller. Each
duct includes a
closure for occluding outflow from the rear of the duct. Formed in the
sidewall of each duct
downstream of the propeller is at least one port. A vane is provided for each
port to control air
flow therethrough. By selectively opening or closing the ports thrust produced
by the engine
assembly may be oriented radially to the axis of the duct to allow improved
control of direction,
altitude or attitude of the airship.
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[00051 While this approach represents a significant advance in the art of
airship steering and an
improvement over prior art airship steering systems, it tends to experience
certain drawbacks.
More specifically, air propelled rearward by the propeller tends to lose
momentum when it is
reoriented or deflected by the vanes, resulting in loss of some thrust and
poor efficiency. As a
result, to be effective such airship propulsion systems would likely be
required to have relatively
large engines (preferably, turbo diesels) with very large propellers. Ducts
accommodating such
engines with very large propellers (e.g. having diameters greater than 10 ft.)
would tend be
exceedingly heavy thereby tending to increase fuel costs. Due to their
significant weight, such
ducts would also tend to be difficult to transport from the place of
manufacture to the airship
assembly site. An additional drawback lies in the fact that steering and
propulsion in this manner
tends to be limited by the configuration of the vanes since orientation of the
thrust produced will
depend on the position of the vanes in the duct.
[00061 In light of the foregoing, it would be advantageous to have a
propulsion and steering
system which would allow improved and more efficient deflection of thrust for
more controlled
steering of an airship at relatively low speeds. Such a system would tend to
facilitate the airship
landing operation and procedure and obviate the need for having a significant
ground crew
during airship landings, thereby tending to reduce airship operating costs.
Advantageously, such
features would enhance the versatility of the airship and allow it to be used
for various
applications.
SUMMARY OF THE INVENTION
[0007] In accordance with one embodiment of the present invention, there is
provided a
propulsion and steering assembly for use with an airship. The airship
possesses a hull having an
outer envelope. The assembly includes an engine for producing thrust to propel
the airship and a
support frame for carrying the engine. The engine is fixed to the support
frame. A support frame
movement mechanism is operable to move the support frame relative to the hull
to thereby allow
the engine and the thrust produced by the engine to be oriented in a desired
direction. The
assembly further includes spacer means connected to the support frame movement
mechanism
for spacing the support frame and the engine from the outer envelope of the
hull so as to create
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sufficient clearance therebetween when the support frame is moved. Also
provided, is a
mounting framework for attaching the spacer means to the hull.
[0008] In another feature, the propulsion and steering assembly further
includes a propeller
operatively connected to the engine. The propeller is selected from the group
consisting of a
push-type propeller and a pull-type propeller.
[0009] In yet another feature, the support frame movement mechanism includes a
dual hinge
assembly. The support frame movement mechanism includes a first actuator for
imparting rotary
movement to the support frame about a first axis of rotation and a second
actuator for imparting
rotary movement to the support frame about a second axis of rotation. The
first axis of rotation is
perpendicular to the second axis of rotation. In one feature, the support
frame depends from the
second rotary actuator. The second actuator is carried by the first rotary
actuator and the first
rotary actuator is mounted to the spacer means. In an alternative feature, the
support frame
depends from the first rotary actuator. The first rotary actuator is carried
by the second rotary
actuator and the second rotary actuator is mounted to the spacer means.
[0010] In a further feature, the first and second rotary actuators are
hydraulic actuators. In an
alternative feature, the first and second rotary actuators are selected from
the group consisting of
pneumatic actuators and electric actuators.
[0011] In another feature, the first actuator is operable to pivot the support
frame and the
engine between a first lateral limit position and a second lateral limit
position. An angle is
defined between the first and second lateral limit positions. In one feature,
the angle is less than
or equal to approximately 180.
[0012] In yet another feature, the second actuator is operable to pivot the
support frame and the
engine between an upper limit position and a lower limit position. An angle is
defined between
the upper and lower limit positions. In one feature, the angle is less than or
equal to
approximately 180.
[0013] In another feature, the support frame movement mechanism is further
provided with
means for restricting movement of the support frame between the first and
second lateral limit
positions, and between the upper and lower limit positions.
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[0014] In yet another feature, the spacer means includes an elongate
structural member
supported from the mounting framework in a cantilevered fashion.
[0015] In a further feature, the mounting framework is curved convexly to
closely correspond
to the radius of curvature of the hull to encourage close contact therebetween
and facilitate
attachment of the mounting framework to the hull.
[0016] In accordance with another broad embodiment of the present invention,
there is
provided an airship. The airship possesses a hull having an outer envelope and
a propulsion and
steering system operatively connected to the outer envelope of the hull. The
system includes at
least one propulsion and steering assembly. The at least one propulsion and
steering assembly
includes an engine for producing thrust to propel the airship and a support
frame for carrying the
engine. The engine is fixed to the support frame. A support frame movement
mechanism is
operable to move the support frame relative to the hull to thereby allow the
engine and the thrust
produced by the engine to be oriented in a desired direction. The at least one
assembly further
includes spacer means connected to the support frame movement mechanism for
spacing the
support frame and the engine from the outer envelope of the hull so as to
create sufficient
clearance therebetween when the support frame is moved. Also provided, is a
mounting
framework for attaching the spacer means to the hull.
[0017] In one feature, the hull is an elongated body and includes a first
conical end portion, a
second end conical portion and a cylindrical intermediate portion extending
between the first and
second conical portions. The intermediate portion has a sidewall. The at least
one propulsion and
steering assembly includes a first propulsion and steering assembly and a
second propulsion and
steering assembly. The first and second propulsion and steering assemblies are
mounted to the
sidewall of the intermediate portion in opposition to each other.
[0018] In a further feature, the at least one propulsion and steering assembly
also includes a
third propulsion and steering assembly and a fourth propulsion and steering
assembly. The third
and fourth propulsion and steering assemblies are mounted to the sidewall of
the intermediate
portion in opposition to each other. The first and second propulsion and
steering assemblies
define a fore pair of steering and propulsion assemblies, and the third and
fourth propulsion and
steering assemblies define an aft pair of steering and propulsion assemblies.
The fore pair of
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steering and propulsion assemblies is disposed on a first plane, and the aft
pair of steering and
propulsion assemblies is disposed on a second plane. In one feature, the first
plane is the same as
the second plane. In an alternative feature, the first plane is different than
the second plane.
[00191 In an additional feature, the fore pair of steering and propulsion
assemblies is mounted
to the intermediate portion adjacent the first conical end portion, and the
aft pair of steering and
propulsion assemblies is mounted to the intermediate portion adjacent the
second conical end
portion.
[00201 In still another feature, the hull of the airship is spherical.
[00211 In accordance with yet another broad embodiment of the present
invention, there is
provided a kit for a steering and propulsion assembly or use with an airship.
The airship
possesses a hull having an outer envelope. The assembly is mountable to the
outer envelope of
the hull. The kit includes an engine for producing thrust to propel the
airship and a support
frame for carrying the engine. The engine is fixable to the support frame. A
support frame
movement mechanism is operable to move the support frame relative to the hull
to thereby allow
the engine and the thrust produced by the engine to be oriented in a desired
direction. The kit
further includes spacer means connectable to the support frame movement
mechanism for
spacing the support frame and the engine from the outer envelope of the hull
so as to create
sufficient clearance therebetween when the support frame is moved. Also
provided, is a
mounting framework connectable to the spacer means and fixable to the hull.
100221 In accordance with still another broad embodiment of the present
invention, there is
provided a method of steering and propelling an airship. The method includes
the steps of
providing an airship. The airship includes a hull having an outer envelope.
Also provided is a
propulsion and steering system operatively connected to the outer envelope of
the hull. The
system includes at least one propulsion and steering assembly. The at least
one propulsion and
steering assembly includes an engine for producing thrust to propel the
airship and a support
frame for carrying the engine. The engine is fixed to the support frame. A
support frame
movement mechanism is operable to move the support frame relative to the hull
to thereby allow
the engine and the thrust produced by the engine to be oriented in a desired
direction. The at least
one assembly further includes spacer means connected to the support frame
movement
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mechanism for spacing the support frame and the engine from the outer envelope
of the hull so
as to create sufficient clearance therebetween when the support frame is
moved. A mounting
framework is provided for attaching the spacer means to the hull. The method
further includes
the steps of actuating the engine to produce thrust and actuating the support
frame movement
mechanism to urge the support frame to move relative to the hull. The thrust
produced by the
engine is oriented in a direction opposite to the desired direction of travel
and the airship is
steered in the desired direction of travel.
BRIEF DESCRIPTION OF THE DRAWINGS
100231 The embodiments of the present invention shall be more clearly
understood with
reference to the following detailed description of the embodiments of the
invention taken in
conjunction with the accompanying drawings, in which:
[0024] FIG. 1 is a front left perspective view of an airship provided with a
propulsion and
steering system according to an embodiment of the present invention, the
propulsion and steering
system including four propulsion and steering assemblies, each of the
assemblies being disposed
in an outward orientation or intermediate position;
[0025] FIG. 2 is a top plan view of the airship shown in FIG. 1;
[0026] FIG. 3 is a front end view of the airship shown in FIG. 1;
[0027] FIG. 4 is a front left perspective view of one of the propulsion and
steering assemblies
shown in FIG. 1;
[0028] FIG. 5 is a front right perspective view of the support frame and
support frame
movement mechanism shown in FIG. 4;
[0029] FIG. 6 is a rear right perspective view of the support frame and
support frame
movement mechanism shown in FIG. 5;
[0030] FIG. 7 is a top plan view of the support frame and support frame
movement
mechanism shown in FIG. 5;
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[0031] FIG. 8 is a left elevation view of the support frame and support frame
movement
mechanism shown in FIG. 5;
[0032] FIG. 9 is an enlarged, isolated, bottom plan view of the propulsion and
steering
assembly illustrated in FIG. 4 showing the support frame movement restricting
means, and the
support frame occupying an outward orientation or intermediate position, the
engine block and
propeller having been omitted for clarity;
[0033] FIG. 10 is a cross-sectional view of the support frame movement
restricting assembly
illustrated in FIG. 9, taken along the cross-section line "9-9";
[0034] FIG. 11 is an enlarged partial, front end view of the airship
illustrated in FIG. 1,
showing in solid lines the support frame pivoted upwardly to its upper limit
position and
showing in dashed lines the support frame pivoted downwardly to its lower
limit position;
[0035] FIG. 12 is a cross-sectional view of the propulsion and steering
assembly similar to that
illustrated in FIG. 9 except that the support frame is shown pivoted
downwardly to its lower limit
position;
[0036] FIG. 13 is a cross-sectional view of the propulsion and steering
assembly similar to that
illustrated in FIG. 9 except that the support frame is shown pivoted upwardly
to its upper limit
position;
[0037] FIG. 14 is an enlarged partial, top plan view of the propulsion and
steering assembly
illustrated in FIG. 1, showing in solid lines the support frame pivoted to its
fore limit position
and showing in dashed lines the support frame pivoted to its aft limit
position;
[0038] FIG. 15 is a view of the propulsion and steering assembly similar to
that shown in FIG.
9, except that the support frame is shown pivoted to its aft limit position;
[0039] FIG. 16 is a top plan view of an alternative embodiment of the airship
illustrated in
FIG. 1, showing the support frames of the first, second, third and fourth
propulsion and steering
assemblies all pivoted to their respective aft limit positions and thrust
being generated by each of
the assemblies to propel the airship in the forward direction from an initial
position shown in
dashed lines to an end position shown in solid lines;
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[0040] FIG. 17 is another top plan view of the airship illustrated in FIG. 16,
showing the
support frames of the first, third and fourth propulsion and steering
assemblies all pivoted to their
respective aft limit positions, the support frame of the second propulsion and
steering assembly
occupying its intermediate position and thrust being generated by each of the
assemblies to
propel the airship forwardly and laterally from an initial position shown in
dashed lines to an end
position shown in solid lines;
[0041] FIG. 18 is a front end elevation view of the airship shown in FIG. 16,
with the support
frames of the first, second, third and fourth propulsion and steering
assemblies all pivoted to
their respective upper limit positions and thrust being generated by each of
the assemblies to
propel the airship downwardly from an initial position shown in dashed lines
to an end position
shown in solid lines; and
[0042] FIG. 19 is a side elevation view of the airship shown in FIG. 16, with
the support
frames of the fore pair of propulsion and steering assemblies pivoted to their
respective upper
limit positions, the support frames of the aft pair of propulsion and steering
assemblies pivoted to
their respective aft limit positions and thrust being generated by each of the
assemblies to propel
the airship downwardly and forwardly from an initial position shown in dashed
lines to an end
position shown in solid lines, to effect a descent maneuver.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0043] The description which follows, and the embodiments described therein
are provided by
way of illustration of an example, or examples of particular embodiments of
principles and
aspects of the present invention. These examples are provided for the purposes
of explanation
and not of limitation, of those principles of the invention. In the
description that follows, like
parts are marked throughout the specification and the drawings with the same
respective
reference numerals.
[0044] In the description and drawings herein, and unless noted otherwise, the
terms "vertical",
"lateral" and "horizontal", are references to a Cartesian co-ordinate system
in which the vertical
direction generally extends in an "up and down" orientation from bottom to top
(z-axis) while the
lateral direction generally extends in a "left to right" or "side to side"
orientation (y-axis). In
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addition, the horizontal direction extends in a "front to back" orientation
and can extend in an
orientation that may extend out from or into the page (x-axis). The force of
gravity, and hence
buoyancy, acts parallel to the z-axis.
[0045] As used in the specification, there are also defined three axes of
rotation with respect to
airships based on the center of gravity of the airship. Typically, the
orientation of an airship can
be defined by the amount of rotation of the parts of the airship along these
three axes. Each axis
of this coordinate system is perpendicular to the other two axes. For example,
the pitch axis is
perpendicular to the yaw axis and the roll axis. A pitch motion or "pitch" is
an up or down
movement of the nose and tail of the aircraft along the z-axis. A yaw motion
or "yaw" is a
movement of the nose of the aircraft from side to side along the y-axis. In
other words, if an
aircraft model placed on a flat surface is spun or pivoted around its center
of mass, it would be
described as yawing. A roll motion or "roll" is a rotational movement of an
airship along the x-
axis. If the airship is thought of as having a vertical, or z-axis, a
longitudinal, or x-axis, and a
transverse, or y-axis, pitch is rotation about the y-axis, roll is rotation
about the x-axis, and
yawing is rotation about the z-axis. When described together, the orientation
of an airship is
typically referred to as "attitude".
[0046] Referring to FIGS. 1 to 3, there is shown an airship designated
generally with reference
numeral 10. The airship 10 has a hull 12 and a propulsion and steering system
14 securely
mounted to the hull 12. The hull 12 includes an outer envelope 16 which is
adapted to contain a
certain amount of a lifting gas which provides buoyancy to the airship 10. The
outer envelope 16
is manufactured from an airtight material and may be formed from panels that
are joined together
so as to be air impermeable, such as by heat welding, sewing, or any other
joining techniques
known to those skilled in the art.
[0047] As best shown in FIG. 2, the hull 12 has a generally elongated
ellipsoidal (or cigar)
shape defined by a fore conical end portion 24, an aft conical end portion 28
and a generally
cylindrical intermediate portion 18 extending between the fore and aft conical
end portions 24
and 28. The intermediate portion 18 meets the fore conical end portion 24
along a first margin
20 and the aft conical end portion 28 along a second margin 22. Each conical
end portion 24, 28
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extends outwardly and away from each respective margin 20, 22, in a tapering
fashion to
ultimately, terminate at an apex 26, 30, respectively.
[0048] The hull 12 has a total length LT which corresponds to the distance
between the apexes
26 and 30 (as shown in FIG. 2); a length Ll which corresponds to the distance
between the apex
26 of the fore conical end portion 24 and the first margin 20; a length L2
which corresponds to
the distance between the first and second margins 20 and 22; a length L3 which
corresponds to
the distance between the second margin 22 and the apex 30 of the aft conical
end portion 28; and
a diameter Dl which corresponds to the diameter of the intermediate portion 18
(as shown in
FIG. 3). In this embodiment, the length LT measures 235 ft.; the length L1
measures 50 ft; the
length L2 measures 135 ft.; the length L3 measures 50; and the diameter Dt
measures 65 ft. In
alternative embodiments, the hull 12 could be sized differently. For instance,
the dimensions LT,
L1, L2, L3 and Dl could be increased or decreased. In still other embodiments,
the hull 12 could
be formed with a different shape altogether. For example, the hull could be
egg-shaped,
cylindrical or spherical, or have any other shape suitable for the desired
application.
[0049] The airship 10 may further include a gondola (not shown) attached to
the hull 12 or,
alternatively, positioned within the interior of the hull 12. The gondola can
be used to carry
passengers or a payload, such as, for example, electromagnetic interface
apparatus,
communication equipment, surveillance equipment, radars or spectral imaging
equipment, or
equipment for controlling the propulsion and steering system 14.
[0050] In the embodiment shown in FIGS. 1 and 2, the propulsion and steering
system 14
includes two pairs of propulsion and steering assemblies identified
generically with reference
numeral 32 - a fore pair 27 of assemblies 32a and 32b and an aft pair 29 of
assemblies 32c and
32d - mounted to the sidewall 33 of the intermediate portion 18. The fore pair
27 of assemblies
32a and 32b is disposed adjacent the first margin 20, while the aft pair of
assemblies 32c and 32d
is disposed adjacent the second margin 22. In other embodiments, both the fore
and aft pairs 27
and 29 could be disposed at different location along the hull 12.
[0051] The assembly 32a of the fore pair 27 and the assembly 32c of the aft
pair 29 are
circumferentially aligned with each other (that is, in the view shown in FIG.
3, if assembly 32a
were projected onto assembly 32c, these assemblies would occupy the same
circumferential
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position on the intermediate portion 18). Similarly, the assemblies 32b and
32d are also
circumferentially aligned with each other. The assemblies 32a and 32b of the
fore pair 27 are
positioned to be diametrically opposed to each other. In like fashion, the
assemblies 32c and 32d
of the aft pair 29 are positioned to be diametrically opposed to each other.
[00521 In this embodiment, all the assemblies 32a, 32b, 32c and 32d lie in the
same generally
horizontal plane PH which cuts through the center of the intermediate portion
18. In other
embodiments, the arrangement of the assemblies could be different. For
instance, each assembly
could be circumferentially staggered from the immediately adjacent assemblies
as desired, such
that two opposed, first and second assemblies lie in the same plane and two
opposed, third and
fourth assemblies lie in a different plane. In a specific example of such an
embodiment, each
assembly could be circumferentially staggered from the immediately adjacent
assemblies by 90
degrees, such that two first and second assemblies are disposed on the plane
PH and the third and
fourth assemblies are disposed on a plane perpendicular to the plane PH.
[00531 It should be appreciated that in other embodiments the propulsion and
steering system
could include a greater or lesser number of propulsion and steering assemblies
disposed in
alternate configurations along the hull. For instance, for smaller cigar-
shaped airships or for
spherical it may be sufficient to have a single pair of opposed propulsion and
steering
assemblies.
[0054) The propulsion and steering assemblies 32a, 32b, 32c, 32d all have the
same general
structure such that the description of one representative assembly - assembly
32b - will suffice
to enable a person skilled in the art to appreciate the details and workings
of all the assemblies
32a, 32b, 32c, 32d. With reference to FIG. 4, the assembly 32b will now be
described in greater
detail. The propulsion and steering assembly 32b includes: an engine block 44
for driving
rotation of a propeller 46; a support frame 42 for carrying the engine block
44; a mechanism 100
for moving the support frame 42 relative to hull 12 to thereby allow the
orientation of the engine
block 44 and propeller 46 to be adjusted; spacer means 36 connected to the
support frame 42 for
spacing the support frame 42, the engine block 44 and the propeller 46 from
the hull 12; and a
mounting framework 34 for fixing the spacer means 36 to the hull 12. As will
be explained in
greater detail below, when the propeller 46 is driven to rotate by the engine
block 44, thrust is
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produced to propel the airship 10. Actuation of the support frame movement
mechanism 100
allows the thrust thus produced to be oriented in a desired direction to
thereby steer the airship.
[0055] The mounting framework 34 has an outer, square-shaped, frame portion 48
and an
inner, cross-shaped, tubular portion 51 attached to the outer frame portion
48. The outer frame
portion 48 is defined by a pair of opposed, first and second horizontal frame
members 50 and 52,
and a pair of opposed, third and vertical fourth frame members 54 and 56
joining the first frame
member 50 to the second frame member 52. In this embodiment, each of the frame
members 50,
52, 54 and 56 is a tubular structural member made of aircraft-grade aluminum,
and measures 10
ft. In other embodiments, the mounting framework 34 could be shaped or sized
differently and
could be manufactured from other suitable materials, for example, from
composites.
[0056] The inner frame portion 51 includes first and second arm portions 58
and 60 arranged
perpendicular to each other to define the cross shape of the inner frame
portion 51. The first arm
portion 58 extends vertically between, and is joined to, the first and second
horizontal frame
member 50 and 52, while the second arm portion 60 runs horizontally between,
and is connected
to, the third and fourth vertical frame members 54 and 56. The first and
second arm portions 58
and 60 intersect at, and are fixed to each other by, a centrally disposed
square plate 70. To
reduce the weight of the mounting framework 34 while still providing the
requisite structural
rigidity, each of the arm portions 58 and 60 is built up from two spaced
apart, tubular members
62 and 64 (in the case of arm portion 58) and 66 and 68 (in the case of arm
portion 60) fastened
to the plate 70. In like fashion to the frame members 50, 52, 54 and 56, the
tubular members 62,
64, 66 and 68 and the plate 70 are also fabricated from aircraft-grade
aluminum. In an
alternative embodiment, the complete mounting framework 34 could be
manufactured from other
suitable materials, for example, composites.
[0057] As best shown in FIGS. 3 and 4, the third and vertical fourth frame
members 54 and 56
of the outer frame portion 48 and the first arm portion 58 of the inner frame
portion 51 are
bowed or curved convexly to closely correspond to the radius of curvature of
the intermediate
portion 18 of the hull 12. This configuration tends to facilitate attachment
of the mounting
framework 34 to the hull 12 by encouraging close contact between the tubular
members of the
mounting framework 34 and the outer envelope 16 of the hull 12. In this
regard, the mounting
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framework 34 is secured to the hull 12 using a plurality of lightweight
flexible sleeves (not
shown) sewn to the outer envelope 16. A portion of these sleeves is wrapped
around the tubular
members 50, 52, 54, 56, 58, 64, 66 and 68 and secured in place by hook and
loop fasteners. A
plurality of cables (not shown) fixed to the outer envelope 16 also serve to
secure the mounting
framework to the hull. It will thus be appreciated that as configured the
attachment framework
34 provides multiple attachment sites for the sleeves and in this manner tends
to distribute the
forces acting on the outer envelope 16 of the hull 12.
[0058] In other embodiments, the mounting framework could be configured
differently.
Instead of being built up of welded tubular members, it could be constructed
of other hollow
structural members assembled using fasteners or other suitable assembly
techniques. Moreover,
the framework could be shaped differently. For instance, it could have a
generally rectangular
shape, or alternatively, it could be made circular (this shape would
particularly well-suited for
use with an airship having a spherical hull). Other shapes could be employed
to similar
advantage. Additionally, while the use of sleeves is the preferred means of
fastening the
mounting framework to the hull, it should be appreciated that this need not be
the case in every
application. In other embodiments, the mounting framework could be attached to
the hull using
cables attached to one or more catenary curtains suspended from an internal
portion of the outer
envelope. Other attachment means could also be used, for example, straps or
webbings. In the
further alternative, the mounting framework could be attached to an internal
frame of the hull.
[0059] Still referring to FIG. 4, in this embodiment, the spacer means 36
takes the form of an
elongate hollow structural member 69 supported in a cantilevered fashion from
the mounting
framework 34. The structural member 69 has a first end 38 fastened to the
plate 70, a second end
40 fixedly connected to a portion of the support frame movement mechanism 100
and an internal
cavity (not shown) defined therein between the first and second ends 38 and
40. The presence of
an internal cavity within the structural member 69 helps reduce the overall
weight of the
propulsion and steering assembly. Additionally, the internal cavity may be
employed to
accommodate various equipment, for instance, one or more of hydraulic pumps,
hydraulic fluid
lines, batteries or fuel cells, thereby shielding such components from the
elements.
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[0060] The spacer means 36 serves a dual purpose - it carries the support
frame 42 and
connects the support frame 42 to the hull 12 and in addition, it creates
sufficient clearance to
prevent the outer envelope 16 of the hull 12 from being damaged by the
propeller 46, the engine
block 44 or the support frame 42, when the first portion 47 of the support
frame 42 is urged to
move. In this embodiment, the structural member 69 is tubular. Its length and
diameter are
selected to resist bending and provide sufficient strength to support the
support frame 42 and the
engine block 44 (and propeller 46) mounted thereon. In this embodiment, the
diameter of the
structural member 69 measures 1 ft. In respect of the length, because of the
structural member's
spacing function, its tends also to be correlated to the diameter of the
propeller 46. In this
embodiment, the length of the structural member measures 6 ft. and the
diameter of the propeller
46 is 10 ft. It should however be understood that the diameter of the
propeller 46 is chosen for
its ability to produce a desired amount of thrust and the length of the
structural member 69 will
be selected to create sufficient clearance for that size propeller. Of course,
the diameter of the
propeller 46, and therefore the length of the structural member 69, could be
adjusted to suit a
particular application. Other changes to the structural member are also
possible. For instance, in
other embodiments, the hollow structural member could be sized with a larger
or smaller
diameter. In still other embodiments, it could be shaped differently. The
hollow structural
member could have a square or rectangular cross-section.
[0061] While it is generally preferred that the spacer means 36 be a unitary
hollow structural
member, this need not be the case in every application. In alternative
embodiments, the spacer
means could be a structural beam (e.g. an I-beam) or further still it could be
a built-up structure
made of welded or otherwise fastened members.
[0062] The support frame movement mechanism 100 is connected to the spacer
means 36 by a
connecting bracket 134. The connecting bracket 134 comprises an annular plate
136 sized to
correspond generally to the diameter of the hollow structural member 69. The
annular plate 136
has a first face 138 (as best shown in FIG. 6) secured to the second end 40 of
the hollow
structural member 69 by welding or other fastening means, and a second face
140 (as best shown
in FIG. 5) opposite the first face 138. Projecting perpendicularly from the
second face 140 is a
pair of spaced apart, upper and lower arms 142 and 144. Each arm 142, 144 has
a generally
triangular shape defined by lateral edges 146 and 148 converging towards a
rounded apex 150
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(as best shown in FIG. 7). Proximate the round apex 150, a relatively large
bore 152 is defined
in each arm 142 and 144. The bore 152 receives a large bolt (not shown) to
resist the shear forces
acting on the arms 142 and 144. The bore 152 in each arm 142, 144 is
surrounded by a number
of smaller openings 154 (in this embodiment, eight openings) disposed in a
ring pattern about the
bore 152. As will be explained in greater detail below, these openings 154
accommodate
fasteners for attaching a portion of the support frame movement mechanism 100
to the
connecting bracket 134.
[00631 With specific reference to FIG. 10, the upper arm 142 is reinforced
with triangular
gusset plates 146 and 148 welded along their respective lower horizontal edges
160 to the top
surface 162 of the upper arm 142, and along their respective vertical edges
164 to the second
face 140 of the annular plate 136. The lower arm 144 is reinforced with a
single gusset plate
166. The gusset plate 166 is formed with four corners 168, 170, 172 and 174,
its shape being
defined by a first horizontal edge 176 extending between corners 168 and 170;
a second,
relatively long, vertical edge 178 extending between corners 170 and 172; a
third angled edge
180 running between corners 172 and 174; and a fourth, relatively short,
vertical edge 182
running between corners 174 and 168. The second and third edges 178 and 180
cooperate with
each other define a wedge-like portion 184. The first horizontal edge 176 is
welded to the bottom
face 191 of the lower arm 144, the second vertical edge 178 is welded to the
sidewall 185 of the
tubular post member 186, and the fourth vertical edge 182 is welded to the
second face 140 of
the annular plate 136. Each of the gusset plates 146, 148 and 166 is formed
with a plurality of
weight reducing perforations 188.
100641 As shown in FIGS. 6 and 8, the tubular post member 186 is welded to the
lower face
191 of the arm 144 and extends downwardly therefrom. At its bottom end 187,
the tubular post
member 186 is formed with a flange 189 projecting radially outward from the
sidewall 185. As
will be made clear below, the tubular post member 186 (and more specifically,
the flange 189)
define part of the support frame movement restricting means 410.
[00651 The support frame movement mechanism 100 is now described in greater
detail with
reference to FIGS. 5 to 8. Preferably, the mechanism 100 employs a dual hinge
design which is
embodied in a first actuator 190 for imparting rotary movement to the support
frame 42 about a
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first axis of rotation V1, and a second actuator 192 for imparting rotary
movement to the support
frame 42 about a second axis of rotation H1 perpendicular to the first axis of
rotation V1. The first
actuator 190 is operable to pivot the support frame 42 (and the engine block
44 and propeller 46)
between a first fore limit position 400 and a second aft limit position 402
(as best shown in FIG.
14). Similarly, the second actuator 192 is operable to upwardly or downwardly
tilt or pivot the
support frame 42 (and the engine block 44 and propeller 46) between an upper
limit position 404
and a lower limit position 406 (as best shown in FIG. 11). The mechanism 100
is further
provided with means 410 for restricting movement of the support frame 42
within a desired
range of movements bound by the first and second limit positions 400 and 402,
and the upper
and lower limit positions 404 and 406.
[0066] In this embodiment, the first rotary actuator 190 is mounted to the
annular plate 136
and carries the second rotary actuator 192, and the support frame 42 depends
from the second
rotary actuator 192. This need not be the case in every application. In other
embodiments, the
arrangement of actuators may be reversed with the second rotary actuator
attached to the annular
plate and carrying the first rotary actuator, while the support frame hangs
from the first rotary
actuator.
[0067] Preferably, the first and second rotary actuators are hydraulic
actuators, as these types
of actuators tend to be responsive, precise and powerful, and capable of
generating significant
amounts of torque. Conceivably though, other types of actuators could also be
used, for
example, pneumatic or electric actuators.
[0068] In this embodiment, the first rotary actuator 190 is a hydraulic rotary
actuator
manufactured by Helac Corporation (Enumclaw, WA, U.S.A.) and sold under the L-
20
SeriesTM brand name. As the structure and workings of this type of actuator
are well-known in
the art, only a very brief, high-level, description of the first rotary
actuator 190 will be provided.
The first rotary actuator 190 has an external body 194 and a rotary assembly
(not shown) housed
within the body 194. The body 194 is defined by a generally cylindrical sleeve
portion 200 and a
pair of spaced apart, upper and lower mounting cross-members (or feet) 202 and
204 welded to
the sleeve portion 200 transverse to its longitudinal axis. As will be
apparent from the description
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that follows, the cross-members 202 and 204 serve to attach the first rotary
actuator 190 to the
second rotary actuator 192.
100691 A port block 206 is mounted to the sleeve portion 200 at a location
opposite the cross-
members 202 and 204 facing the annular plate 136. The port block 206 houses a
plurality of
ports which allow hydraulic fluid to flow into (or out of) the first rotary
actuator 190 and a
plurality of valves for regulating flow of hydraulic fluid and the pressure
within the rotary
assembly. Although not shown, hydraulic feed lines operatively connected to a
hydraulic pump
and an actuator controller are provided to deliver (or remove) hydraulic fluid
to (or from) the
ports.
100701 The rotary assembly includes upper and lower rotary elements (not
shown). The sleeve
portion 200 is rotatable relative to the upper and lower rotary elements, such
that when the first
actuator assembly 190 is actuated, it is the sleeve portion 200 which will be
permitted to pivot or
rotate about the first rotational axis V1. The top face of the upper rotary
element and bottom face
of the lower rotary element each have a plurality of openings (not shown)
similar in size and
layout to the openings 154 defined in the upper and lower arms 142 and 144.
The openings in
the top face of the upper rotary element are alignable with the openings 154
in the upper arm 142
to permit the insertion of fasteners 208 therethrough to secure the upper
rotary element to the
upper arm 142. Likewise, the openings in the bottom face of the lower rotary
element are
alignable with the openings 154 in the lower arm 144 to allow fasteners (not
shown) to be
inserted therethrough to secure the lower rotary element to the lower arm 144.
[00711 It will be appreciated that the first rotary actuator 190 in
combination with the upper
and lower arms 142 and 144 defines a vertical hinge operable to permit the
support frame 42 to
pivot about the first axis of rotation V1. When the first rotary actuator 190
is actuated, the action
of the pressurized hydraulic fluid within the rotary assembly urges the sleeve
portion 200 to
pivot relative to the rotary elements which are fixed to the mounting arms 142
and 144. This
rotary motion is transferred to the support frame 42 (and ultimately, to the
drive block 42 and
propeller 46) through the second rotary actuator 192.
[00721 The second rotary actuator 192 is generally similar to the first rotary
actuator 190, in
that it too has an external body 210 which houses a rotary assembly (not
shown). However, in
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contrast to the body 194 which has a vertical orientation, the body 210
extends horizontally. The
body 210 is defined by a generally cylindrical sleeve portion 214 and a pair
of spaced apart, first
and second lateral mounting cross-members (or feet) 216 and 218 welded to the
sleeve portion
214 transverse to its longitudinal axis. The cross-members 216 and 218 are
bolted onto the cross-
members 202 and 204. While bolting is the preferred means of fastening the
cross-member 216
and 218 to the cross-members 202 and 204, in other embodiments, the cross-
members could be
releasably attached using other known means. Alternatively, the cross-members
could be secured
to each other with a permanent connection (e.g. by welding).
100731 The second rotary actuator 192 also possesses a port block 220 having a
plurality of
ports (not shown) and valves (not shown), similar to port block 206. The port
block 220 is
mounted to the sleeve portion 214 at a location opposite the cross-members 216
and 218.
Although not shown, hydraulic feed lines operatively connected to a hydraulic
pump and an
actuator controller are provided to deliver (or remove) hydraulic fluid to (or
from) the ports of
the port block 220.
100741 The rotary assembly of the second rotary actuator 192 resembles the
rotary assembly of
the first rotary actuator 190 described above in that it includes first and
second rotary elements
(not shown). The first and second rotary elements are rotatable relative to
the sleeve portion 214
and are configured for coordinated co-rotation. Contrary to the first actuator
assembly 190
where the upper and lower rotary elements remain fixed and the sleeve portion
200 is permitted
to pivot or rotate, in the second actuator assembly 192 it is the first and
second rotary elements
which are permitted to rotate while the sleeve portion 214 remains fixed.
[00751 The lateral faces of each of the first and second rotary elements have
a plurality of
openings (not shown) disposed in a ring pattern. As will be explained in
greater detail below,
these openings are alignable with corresponding openings formed in the upper
ends 230 of the
lateral, obround-shaped, connector arms 224 and 226 to permit the insertion of
fasteners 228
therethrough to secure the first and second rotary elements to the connector
arms 224 and 226.
100761 It will be appreciated that the second rotary actuator 192 in
combination with the lateral
connector arms 224 and 226 defines a horizontal hinge operable to permit the
support frame 42
to pivot about the second axis of rotation H1. When the second rotary actuator
192 is actuated,
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the action of the pressurized hydraulic fluid within the rotary assembly urges
the sleeve portion
214 to pivot relative to the rotary elements which are fixed to the connector
anus 224 and 226.
This rotary motion is transferred to the support frame 42 (and ultimately, to
the drive block 42
and propeller 46).
[0077] In this embodiment, the second rotary actuator 192 is also a hydraulic
rotary actuator
manufactured by Helac Corporation (Enumclaw, WA, U.S.A.) and sold under the L-
20
SeriesTM brand name.
[0078] While it is generally preferred that the support frame movement
mechanism 100
employ rotary actuators in a dual hinge design because of ease of use and
manufacturing, it will
be appreciated that alternate movement imparting mechanisms could be used to
similar
advantage. For instance, in another embodiment, the support frame movement
mechanism could
take the form of linear actuators or even an arrangement of cable pulleys.
[0079] With reference to FIGS. 5, 7 and 8, the support frame 42 is now
described in greater
detail. The support frame 42 has a generally trapezoidal shape when seen in a
top plan view. It
includes a base portion 240 and an upper portion 242 connected to the base
portion 240. The
base portion 240 is defined by a pair of first and second, spaced apart,
longitudinal members 244
and 246, a first intermediate cross-member 248 and an end cross-member 250.
Each longitudinal
member 244, 246 has a first end 252, 254 and a second end 256, 258,
respectively. In this
embodiment, the longitudinal members 244 and 246 are not disposed parallel to
each other.
Rather, the distance between the first ends 252 and 254 of the longitudinal
members 244 and 246
is greater than the distance between the second ends 256 and 258, such that
the base portion 240
is wider at the region of the first ends 252 and 254 than in the region of the
second ends 256 and
258. At a location closer to second ends 256 and 258 than to the first ends
252 and 254, the first
intermediate cross-member 248 extends between and joins the first longitudinal
member 244 to
the second longitudinal member 246. The end cross-member 250 is welded to each
longitudinal
member 244 and 246 at its respective second end 252, 254.
[0080] The top portion 242 also includes a pair of third and fourth, spaced
apart, longitudinal
members 260 and 262 connected to the end cross-member 250 and a second
intermediate cross-
member 264. Each of third and fourth longitudinal members 260 and 262 has a
first end 266,
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268 and an opposed second end 270, 272, respectively. When viewed in top plan
as shown in
FIG. 7, the third and fourth longitudinal members 260 and 262 are seen to be
arranged similarly
to the first and second longitudinal members 244 and 246, with the top portion
242 being is
wider at the region of the first ends 266 and 268 than in the region of the
second ends 270 and
272. Each longitudinal member 260 and 262 is cut on an angle at its respective
first end 266,
268 to facilitate the welding of the members to the end-cross member 250 and
to allow the
longitudinal members 260 and 262 to be carried above the base portion 240 at
an incline (as best
shown in FIG. 8). In this embodiment, the angle formed between the end cross-
member 250 and
the longitudinal members 260 and 262 is 20 degrees. In like fashion to the
first intermediate
cross-member 248, the second intermediate cross-member 264 joins the third
longitudinal
member 260 to the fourth longitudinal member 262 at a location closer to
second ends 270 and
272 than to the first ends 266 and 268.
[0081] In this embodiment, the longitudinal members and the cross-members are
all hollow
aluminum structural members. In other embodiments, these members may be
fabricated from
steel or other suitable materials. The first and second longitudinal members
244 and 246, the
third and fourth longitudinal members 260 and 262, the first and second
intermediate cross-
members 248 and 264, and the end cross-member 250 cooperate with each other to
define a
generally trapezoidal station 278 which is sized to receive the engine block
44.
[00821 The second end 256 of the first longitudinal member 244 is joined to
the second end
270 of the third longitudinal member 260 by a first vertically extending panel
280. Similarly, a
second vertically extending panel 282 connects the second end 258 of the
second longitudinal
member 246 to the second end 272 of the fourth longitudinal member 262. Each
panel 280, 282
includes a lower end 284 welded to the inside face of the longitudinal member
244 or 246 (as the
case may be) and an upper end 286 welded to the inside face of the
longitudinal member 260 or
262 (as the case may be). The upper end 286 of each panel 280, 282 is
truncated to match the
profile of the upper face of the third and fourth longitudinal members 260 and
262. When viewed
from the side (as shown in FIG. 8), the first and third longitudinal member
244 and 260 and the
panel 280 on one side, and the second and fourth longitudinal members 246 and
262 and the
panel 282 on the other side, each have a generally triangular structure which
tends to be well-
suited for resisting bending moments acting on the support frame 42.
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[00831 Extending between the lower and upper ends 284 and 286 of the panels
280, 282 are
opposed vertically extending side edges 288 and 290. Formed in the side edge
288 of each panel
280, 282 (that is, the side edge furthest from the end cross-member 250) is a
generally semi-
circular cutout 292 sized to accommodate therein a substantial portion of a
tubular cross-member
294. As best shown in FIGS. 6 and 8, the tubular cross-member 294 is carried
below, and
parallel to, the second rotary actuator 192. It extends horizontally between
the panels 280 and
282 and is welded thereto where its radial edges meet the side edges 290. At
locations inwardly
of the panels 280 and 282, the tubular cross-member 294 joins the lateral
connector arms 224
and 226 which depend downwardly from the second rotary actuator 192. More
specifically, the
tubular cross-member 294 is received through large apertures defined in the
lower ends 300 of
the connector arms 224 and 226 and is fixedly secured thereto by welding along
those radial
edges abutting the connector arms 224 and 226. When the second actuator
assembly 192 is
actuated, the rotary motion from the rotary elements is transmitted through
the connector arms
224 and 226 to the tubular cross-member 294. By reason of its fixed attachment
to the panels 280
and 282, the rotary motion of tubular cross-member 294 is imparted to the
panels 280 and 282
(and ultimately, to the base portion 240 and top portion 242) thereby
effecting rotation of the
support frame 42.
[0084] As best shown in FIG. 6 and 10, the tubular cross-member 294 has an
abutment pad or
stop 296 attached to its sidewall 298 midway between the lateral connector
arms 224 and 226.
The outer face of the stop 296 is indented concavely to correspond closely to
the arcuate profile
of the tubular post member 186. As explained in greater detail below, the stop
296 forms part of
the support frame movement restricting means 410. More specifically, when the
support frame
42 is pivoted to its lower limit position 406, the stop 296 is urged against
the sidewall 185 of the
tubular post member 186, thereby preventing any further downward movement of
the support
frame 42.
[0085] A pair of relatively small, spaced apart, lugs 420 and 422 are welded
to the underside of
the tubular cross-member 294 between the connector arms 224 and 226 (see FIG.
9). Each lug
420 and 422 has a substantially trapezoidal bore 424 defined therein oriented
generally
perpendicular to the tubular cross-member 294. Each bore 424 is sized to
receive therethrough a
portion of the U-shaped retaining rod 426.
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[00861 As best shown in FIG. 7, the support frame 42 is further provided with
reinforcement
members in the nature of diagonal braces 302 and 304, and struts 306 and 308.
The brace 302
includes a relatively short, straight portion 310 and a relatively longer, dog-
legged portion 312
joined to the straight portion 310. The straight portion 310 is welded to the
inner face of the
fourth longitudinal member 262 adjacent the second intermediate cross-member
264, while the
terminal end of the dog-legged portion 312 is welded to the outer face of the
connector arm 224.
The brace 304 has a structure generally similar to that of brace 302 in that
it too has a relatively
short, straight portion 314 and a relatively longer, dog-legged portion 316
joined to the straight
portion 314. However, the dog-legged portion 316 is shorter than the dog-
legged portion 312. In
the case of brace 304, the straight portion 310 is welded to the inner face of
the third longitudinal
member 260 a short distance away from the second intermediate cross-member
264, while the
terminal end of the dog-legged portion 316 is welded to the outer face of the
connector arm 226.
[00871 In this embodiment, the strut 306 takes the form of a flat bar 320
having a first end 322
and a second end 324. The strut 306 is mounted to extend between connector arm
226 and the
panel 282, more specifically, with its first end 322 welded to the outer face
of the connector arm
226 adjacent the terminal end of the dog-legged portion 312 and its second end
324 fixed to the
inner face of the panel 282. The strut 308 is generally similar to strut 306
in that it too is a flat
bar 330 having first and second ends 332 and 334. However, the strut 308 is
relatively shorter
than the strut 306. The first end 332 of the strut 308 is welded to the outer
face of the connector
arm 224 adjacent the terminal end of the dog-legged portion 316, while its
second end 334 is
fixed to the inner face of the panel 280.
[00881 As best shown in FIG. 7, the support frame 42 is not symmetrical about
its longitudinal
midline "M". The first and second rotary actuators 190 and 192 are not
centered between the
first and second longitudinal members 244 and 246. Rather, the actuators 190
and 192 and the
attachment site to spacer means 36 are offset toward the first and third
longitudinal members 244
and 260. This configuration is intended to accommodate the distribution of
forces and moments
acting on the support frame 42 when the propeller 46 is driven to rotate and
the actuators 190 and
192 are actuated, and to account for the fact that, in this embodiment, the
center of mass of the
engine block 44 is not positioned at the geometric center of the engine block
44.
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[00891 In alternate embodiments, the support frame could be configured
differently.
Moreover, while in this embodiment the support frame 42 and the support frame
movement
mechanism 100 are distinct components, it is possible that in other
embodiments, the function of
the movement mechanism could be more closely incorporated in the structure of
the support
frame.
[0090] Referring now to FIGS. 4, 11 and 14, there is shown the engine block 44
and propeller
46 carried by the support frame 42. In this embodiment, the engine block 44 is
supported on,
and fixed to, the cross-members 250 and 264 of the base portion 240. However,
in other
embodiments, the engine block could be attached differently to the base
portion of the support
frame. While not shown in the figures, the engine block 44 is encased in a
protective cowling.
[0091] In this embodiment, the engine block 44 includes an 82 h.p. diesel-
powered combustion
engine 340 operatively connected to the propeller. The engine 340 is a
conventional engine that
has been modified to incorporate a propeller speed reduction unit (not shown)
and a dry sump
system to ensure continual flow of lubricating oil to the engine 340 even when
the engine block
44 is tilted upwardly or downwardly. In alternative embodiments, the
propulsion and steering
assemblies 32 could be powered by other types of engines. For instance,
gasoline, propane or
natural gas powered combustion engines could be employed. Alternatively,
turbine engines or
electric motors powered by generators may be used. In a further alternative,
it may be possible
to power the assemblies with solar cells or fuel cells.
[0092] The propeller 46 is operatively coupled to a drive shaft (not visible)
extending from the
engine 340 with sufficient clearance provided between the propeller 46 and the
end cross-
member 250. In this embodiment, the propeller 46 is a push-type propeller
provided with three
blades 342. The diameter of the propeller 46 measures 10 ft. In alternative
embodiments, the
propeller could be a pull-type propeller with three blades (or a greater or
lesser number of
blades). Additionally, the diameter of the propeller could be sized
differently based on the thrust
required to be produced. For instance, if less thrust is required to be
produced, then a smaller
diameter propeller may be used (e.g. 6 ft. diameter propeller). Alternatively,
if more thrust is
required a propeller having a larger diameter could be employed.
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[00931 The support frame movement restricting means 410 is now described in
greater detail
with reference to FIGS. 9 to 16. In this embodiment, the movement restricting
means 410 is
partially defined on the one hand, by the stop 296 carried on the tubular
cross-member 294, and
on the other hand, by the U-shaped rod 426 captively retained at one end by
the flange 189 of the
tubular post member 186, and at the other end by the lugs 420 and 422. As
concerns the U-
shaped rod 426 it includes an arcuate portion 428 and a pair of parallel arms
430 and 432 joined
to the curved portion 428. The radius of curvature of the arcuate portion 428
is sized slightly
larger than that of the sidewall 185 of the tubular post member 186 to allow
it to be received
within the flange 189. At their respective terminal ends 434, each arm
portions 430, 432 is
threaded to allow threaded engagement with a nut 436. The arm portion 430 is
received within
the bore 424 of the lug 420 and similarly, the arm portion 432 extends through
the bore 424 of
the lug 422. In each case, the fastening of the nuts 436 on the terminal ends
434 of the arm
portions 430 and 432, prevents the arm portions from becoming disengaged from
the lugs 420
and 422. The nuts 436 are sized larger than the bores 424 defined in the lugs
420 and 422.
100941 As best shown in FIGS. 9 and 10, when the support frame 42 is in the
outward
orientation or intermediate position 440 (i.e. the support frame is midway
between the first and
second limit positions 400 and 402, and midway between the upper and lower
limit positions 404
and 406), the stop 296 is spaced from the sidewall 185 of the tubular post
member 186 and the
arcuate portion 428 of the retaining rod 426 is carried at the same height as
the arm portions 430
and 432.
[00951 The movement restricting means 410 further includes an internal stop
(not shown) built
into each of the rotary actuators 190 and 192 which may be set to limit travel
to a predetermined
angle. Additionally, the actuator controller is operable to limit rotational
movement of the
support frame 42. In an alternative embodiment, the movement restricting means
could be
configured without a tubular post member, stop and U-shaped rod arrangement.
In such an
embodiment, the movement restricting function could be performed by the
internal stops built
into the rotary actuators.
[00961 An exemplary description of the operation of the support frame movement
mechanism
100 and the movement restricting means 410 is now described. To pivot the
support frame 42
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about the first rotational axis Vi, the pilot of the airship 10 actuates the
first rotary actuator 190
to urge the sleeve portion 200 to rotate relative to the upper and lower
rotary elements. As
previously mentioned, the support frame 42 is constrained to move between the
first and second
limit positions 400 and 402. When the support frame 42 reaches the first or
second limit position
400 or 402, the movement restricting means 410 engages and prevents any
further rotational
movement of the support frame 42 about the first rotational axis V1. When, for
example, the
second limit position 402 is reached (as shown in FIG. 15), the internal stop
within the first
rotary actuator 190 operates to block any further rotation of the support
frame 42 in that
direction.
[0097] A first angle 01 is defined between the first limit position 400 and
the intermediate
position 440. Similarly, a second angle 02 is defined between the second limit
position 402 and
the intermediate position 440. In this embodiment, the first and second angles
01 and 02 are equal
to each other and measure 45 degrees. The rotational range of motion for the
support frame 42
between the first limit position 400 and the second limit position 402 is thus
90 degrees.
[0098] In other embodiments, the values of angles 01 and 02 could be increased
or decreased to
suit a particular application. For example, in one alternative embodiment, the
support frame
movement mechanism 100 could be modified to permit the angles 01 and 02 to
reach 90 degrees
each to thereby afford the support frame with 180 degrees of rotational range
of motion about the
first rotational axis V1. This rotational range of motion would provide an
airship equipped with
such propulsion and steering assemblies enhanced steering capabilities as
described in greater
detail below. Such an embodiment is shown in FIGS. 16 to 19, wherein the
alternate airship is
designated with reference numeral 500 and first, second, third and fourth
modified propulsion
and steering assemblies are designated, respectively, with reference numerals
502a, 502, 502c
and 502d (and collectively, with reference numeral 502) . The modifications to
the support frame
movement mechanism of the assemblies 502 could include, for example,
lengthening the upper
and lower arms of the connecting bracket (which carry the first rotary
actuator) so as to create
sufficient clearance between the support frame and the spacer means when the
support frame is
moved to either the first limit position or the second limit position. It will
be appreciated that the
increased rotational range of motion described above could be achieved with
other modifications
to the support frame movement mechanism and/or the support frame.
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[0099] While it is generally preferred that angles 01 and 02 be equal to each
other that need not
be the case in every application. In certain applications, it may be desirable
to have one of the
angles 01 and 02 larger than the other so as to provide a greater range of
motion in one direction
than in the other.
[00100] To pivot the support frame 42 about the second rotational axis H1, the
pilot of the
airship 10 actuates the second rotary actuator 192 to urge the first and
second rotary elements to
rotate relative to the sleeve portion 214. As previously mentioned, the
support frame 42 is
constrained to move between the upper and lower limit positions 404 and 406.
When the support
frame 42 reaches the upper limit position 404, the movement restricting means
410 engages and
prevents any further rotational movement of the support frame 42 about the
second rotational
axis H1. More specifically, the nuts 436 fastened to the arm portions 430 and
432 bear against
the lugs 420 and 422 and prevent any further travel of the arm portions 430
and 432 within their
respective lugs 420 and 422, thereby blocking further rotation in the upward
direction (see FIG.
13). At this stage, the arm portions 430 and 432 are carried at a height
slightly higher than the
arcuate portion 428. When the support frame 42 reaches the lower limit
position 404, the stop
296 bears against the sidewall 185 of the tubular post member 186 and prevents
any further
rotation in the downward direction (see FIG. 12).
[00101] A third angle 03 is defined between the upper limit position 404 and
the intermediate
position 440. Similarly, a fourth angle 04 is defined between the lower limit
position 406 and the
intermediate position 440. In this embodiment, the angles 03 and 04 are equal
to each other and
measure 11 degrees. The rotational range of motion for the support frame 42
between the upper
limit position 404 and the lower limit position 406 is thus 22 degrees.
[00102] In other embodiments, the values of angles 03 and 04 could be
increased or decreased to
suit a particular application. For example, in one alternative embodiment, the
support frame
movement mechanism 100 could be modified to permit the angles 03 and 04 to
reach 90 degrees
each to thereby afford the support frame 42 with 180 degrees of rotational
range of motion about
the second rotational axis H1. This rotational range of motion would provide
an airship equipped
with such propulsion and steering assemblies enhanced steering capabilities as
described in
greater detail below. Such an embodiment is shown in FIGS. 16 to 19. The
modifications to the
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support frame movement mechanism could include, for example, configuring such
mechanism
without a tubular post member, stop and U-shaped rod arrangement and
increasing the depth of
the first and second lateral mounting cross-members of the second rotary
actuator so as to create
sufficient clearance between the support frame and the support frame movement
mechanism. Of
course, the increased rotational range of motion described above could be
achieved with other
modifications to the support frame movement mechanism and/or the support
frame.
[00103] While it is generally preferred that angles 03 and 04 be equal to each
other that need not
be the case in every application. In certain applications, it may be desirable
to have one of the
angles 03 and 04 larger than the other so as to provide a greater range of
motion in one direction
than in the other.
[00104] Generally speaking, the greater the values of angles 01, 02, 03 and 04
the greater
rotational range of motion afforded to the airship 10 and the more
maneuverable it becomes.
[00105] Having described the structure of a representative propulsion and
steering assembly, an
exemplary use of the assemblies 32a, 32b, 32c and 32d to propel and steer the
airship 10 is now
described. When all engines 340 are powered up, the first propulsion and
steering unit 32a
produces a first thrust T1, the second propulsion and steering assembly 32b
produces a second
thrust T2, the third propulsion and steering assembly 32c produces a third
thrust T3 and the fourth
propulsion and steering unit 32d produces a fourth thrust T4. When, as shown
in FIG. 2, the
support frames 42 of each of the assemblies 32a, 32b, 32c and 32d are in their
respective
intermediate positions 440, the airship 10 is at a standstill with the thrust
Tl counteracting the
thrust T2 and the thrust T3 counteracting the thrust T4. This arrangement
tends to be useful in
applications where it is desirable to have the airship 10 hover over a
particular site.
[00106] To steer the airship 10 in a desired direction of travel and/or impart
the desired motion
(i.e. pitch, yaw or roll motion, or any combination of the foregoing) thereto,
the pilot of the
airship 10 will actuate one or more of the rotary actuators 190 and 192 of one
or more of the
assemblies 32a, 32b, 32c and 32d, so as to urge one or more of the support
frames 42 to move
relative to the hull 12. The movement of one or more of the support frames 42
will permit one or
more of the thrusts T1, T2, T3, T4 to be oriented in an direction opposite to
the desired direction of
travel, thereby steering and propelling the airship in the desired direction
of travel.
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100107] Examples of the types of steering operations that can be executed
using the propulsion
and steering assemblies 502, are described below with reference to FIGS. 16 to
19. FIG. 16
shows the support frames 504 of the first, second third and fourth propulsion
and steering
assembly 502a, 502b, 502c and 502d pivoted rearward to their respective aft
limit positions. In
this arrangement, the thrusts T1, T2, T3 and T4 produced by the assemblies 502
are oriented
rearward thereby propelling the airship 500 linearly in a forward direction
indicated by the arrow
"F". To propel the airship 500 linearly in the rearward direction, the support
frames 504 of the
assemblies 502 are pivoted forward to their respective fore limit positions.
[00108] FIG. 17 shows the support frames 504 of the first, third and fourth
propulsion and
steering assemblies 502a, 502c and 502d all pivoted to their respective aft
limit positions and the
support frame of the second propulsion and steering assembly 502c in its
intermediate position.
In this arrangement, the thrusts T1, T3 and T4 produced by the assemblies
502a, 502c and 502d
are oriented rearward while the thrust T2 produced by the assembly 502b is
oriented laterally or
outwardly. The resulting motion imparted to the airship 500 is generally in
the forward direction
with the nose 506 of the airship 500 turning in a direction opposite to the
lateral orientation of
the support frame 504 of assembly 502b. This type of arrangement is useful for
effecting a yaw
motion.
100109] FIG. 18 shows the support frames 504 of the first, second, third and
fourth propulsion
and steering assemblies 502a, 502b, 502c and 502d all pivoted to their
respective upper limit
positions. In this arrangement, the thrust T1, T2i T3 and T4 produced by the
assemblies 502a, 502c
and 502d are oriented upward thereby propelling the airship 500 in a generally
downward
direction indicated by arrow "D". Advantageously, this type of propulsion and
steering
capability could substantially facilitate landing of the airship 500 and could
operate to reduce the
need for the presence of significant ground crews during landing operations.
[00110] FIG. 19 shows the support frames 504 of the fore pair of (first and
second) propulsion
and steering assemblies 502a and 502b pivoted to their respective upper limit
positions and the
support frames 504 of the aft pair of (third and fourth) propulsion and
steering assemblies 502c
and 502d pivoted to their respective aft limit positions. In this arrangement,
the thrusts T1 and T2
produced by the assemblies 502a and 502b are oriented upward thereby
propelling the nose 506
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of the airship 500 downward, while the thrusts T3 and T4 produced by the
assemblies 502c and
502d are oriented rearward thereby propelling the airship 500 forward. The
resulting motion
imparted to the airship 500 is a pitch motion, which tends to be particularly
useful for effecting a
descent maneuver. Of course, an ascent maneuver could be performed by pivoting
the support
frames 504 the fore pair of (first and second) propulsion and steering
assemblies 502a and 502b
to their respective lower limit positions, while maintaining the support
frames 504 of the aft pair
of (third and fourth) propulsion and steering assemblies 502c and 502d in
their respective aft
limit positions.
[00111] Other maneuvers may be performed using the propulsion and steering
assemblies 502.
For instance, a roll motion may be imparted to the airship 500 by pivoting the
support frames of
the second and fourth assemblies 502b and 502d upwardly or downwardly while
pivoting the
support frames of the first and third assemblies 502a and 502c in the opposite
direction. It will
be further appreciated that any combination of yaw, roll and pitch movements
may be used in
order to maneuver the airship 500 as desired. Moreover, each of the assemblies
502a, 502b,
502c and 502d may be pivoted independently in order to orient their respective
thrusts T1, T2, T3,
and T4 to achieve the desired attitude for the airship 500.
[00112] As will be appreciated by a person skilled in the art, by reason of
its design and
configuration, a propulsion and steering system constructed in accordance with
the principles of
the present invention tends to permit more efficient orientation of the thrust
produced, thereby
tending to minimize loss of thrust (and power). In the result, a more powerful
and responsive
propulsion and steering system is obtained. Such a system is particularly
useful for steering
airships during very low speed approaches (e.g. landings or take-offs) or
other maneuvers
requiring precise positioning of the airship. Advantageously, this innovative
propulsion and
steering system allows an airship to perform tasks which conventional airships
tend to be ill-
suited to perform. For instance, an airship outfitted with a propulsion and
steering system
constructed in accordance with the principles of the present invention could
be successfully
employed in the following applications: it could be used to load or unloading
goods while
hovering; in the case of a heavy-lift airship, it could be used to precisely
position a heavy load; it
could be used to perform aerial geophysical surveys which require that the
airship accurately
follow both the "survey line" and the contour of the land being surveyed; and
in cases where the
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airship is used in search and rescue applications, it could be employed to
hover precisely over a
specific location to allow a person or equipment to be hoisted up onto the
airship using a winch.
[00113] Furthermore, the type of propulsion and steering system described and
shown in this
application tends to weigh less than prior art propulsion and steering
systems, thereby offering
the potential for cost savings on fuel and even increased payload capacity.
[00114] Although the foregoing description and accompanying drawings relate to
specific
preferred embodiments of the present invention as presently contemplated by
the inventor, it will
be understood that various changes, modifications and adaptations, may be made
without
departing from the spirit of the invention.
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