Convertible airship

A gondola, or cabin structure, is attached to a lighter-than-air gas-containing structure by mounting apparatus enabling rotation of the longitudinal axis of the gas-containing structure through about 90.degree. with respect to the orientation of the gondola. Propulsion devices are mounted on the gas-containing structure to provide propulsion force generally parallel to the longitudinal axis of the gas-containing structure for generating forward thrust during flight and downward or upward thrust during, respectively, descent or ascent. Accordingly, the present invention embraces a method for effecting descent or ascent, which includes the steps of orienting the gas-containing structure in a generally vertical configuration and initiating downward or upward thrust. Advantageously, propulsion devices may be provided on rotatably mounted horizontal stabilizers and/or, when used, rotatably mounted wing structures, to provide horizontally oriented thrust when the gas-containing structure is vertical for stabilizing the gas-containing structure in high winds. Also advantageously, anchoring apparatus are provided only on the gondola for permitting the airship to be anchored substantially only by the gondola.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to FIGS. 1 and 2, the airship according to the invention 
comprises gas-containing envelope 10 adapted to contain a lighter-than-air 
gas. Envelope 10 may be a substantially all-fabric structure whose shape 
is maintained through internal gas pressures (such as in a blimp) as shown 
in FIG. 7 or it may be a rigid-frame/fabric structure (dirigible) such as 
that shown in FIG. 4. The airship envelope 10 has rigid structural/track 
support member 12 mounted substantially along the underside of the 
envelope. Advantageously, structural/track member 12 extends from a point 
aft of the midsection to a point above the nose of the gas envelope. 
Gondola 16 is pivotally and slidably mounted to structural/track member 12 
by mounting means 18 which may form the upper end of gondola support 
member 40. Mounting means 18 is fitted onto structural/track member 12 
such that gondola may "slide" laterally along member 12 and rotate about 
said mounting means at any point on member 12. 
Referring now to FIG. 9a, structural/track member 12 may be a channel beam 
having web section 23, extended low flange 20 and upper flange 21. 
Mounting means 18 comprises roller means 24, on axle means 24a, which 
rides on the upper surface of flange 20. Bracing means 25 which may be a 
vertically oriented post is formed on yoke or cradle 19 portion of support 
member 40. Bracing means 25 is preferably maintained in close proximity to 
web 23 in order to steady gondola 16 as it slides and/or pivots and to 
prevent mounting means 18 from becoming disengaged from structural/track 
member 12. Alternatively, bracing means 25 may include second roller means 
27 having its axis of rotation substantially parallel to web 23 as shown 
in FIG. 9b in order to allow substantially frictionless movement of the 
gondola as it slides and/or pivots with respect to member 12. 
According to another aspect of the present invention, structural/track 
member 12 can be an angle beam having web 23 and flange 20 as shown in 
FIG. 9b. Mounting member 18 may be substantially similar to that described 
for use with the channel beam. It is particularly useful for this 
embodiment that cradle 19 of mounting member 18 be formed so as to ride 
close to the bottom of lower flange 20 in order to prevent roller 24 of 
mounting member 18 from rising to either puncture the gas envelope or 
"derail" from the track. 
Alternatively, structural/track member 12 can be a T-beam including web 23 
and two flanges 20 as shown in FIG. 9c. Mounting means 18 can comprise a 
double roller cradle 19 having two roller means 24 which ride, one each, 
on the two flanges 20. As discussed above with reference to FIG. 9b, the 
cradle 19 may be formed close to the bottom of beam flanges 20 in order to 
prevent puncture of the gas envelope, or derailment. 
In the preferred embodiment, as depicted in FIG. 9d, structural/track 
member 12 comprises an I-beam comprising web section 23, two upper flanges 
21 and two lower flanges 20. Two channels 22, separated by web 23, are 
defined in the I-beam to accommodate two roller means 24 for mounting the 
gondola onto track member 12. Thus, the gondola is capable of both pivotal 
and slidable movement with respect to the gas envelope as shown in FIGS. 1 
and 2. Cradle 19 of mounting means 18 may be formed in any convenient 
configuration since upper flanges 21 contain the mounting member 18 to 
prevent puncture of envelope 10 or derailing. 
In order to control the flight of an airship according to the present 
invention, the airship is provided with tail wing assembly 14 comprising 
at least one vertical stabilizer 26 and two horizontal stabilizers 29 
which can be formed with rudders and ailerons respectively. 
Advantageously, the operable portions of the tail wing assembly may be 
remotely controlled by remote control means illustrated in cut-away in 
FIG. 3a) from the gondola. 
In a particularly useful embodiment of the present invention, the 
horizontal stabilizers may be completely pivotally attached to the gas 
envelope, as shown in FIG. 2, for enhancing the stability of the airship. 
Accordingly, while the gondola traverses from its "normal" position below 
the belly of gas-containing envelope 10 (to rotate the longitudinal axis 
of the gas envelope), the horizontal stabilizers can be simultaneously 
rotated through 90.degree. such that their axes remain substantially 
parallel to the ground or to the wind velocity thereby lending additional 
stability to the vertically extending gas envelope, especially during its 
rotating maneuvers. Advantageously, wings 29a may be added to the airship, 
and pivotally mounted to envelope 10, as shown by FIGS. 1-2. Wings 29a may 
be rotated substantially synchronously with the horizontal stabilizers to 
further enhance the airship's stability. Furthermore, when envelope 10 is 
oriented in or is being reoriented to a vertical configuration, propulsion 
means 28 may be continuously operated so as to assist maintaining the 
airship in a substantially stationary posture. This is particularly useful 
to prevent appreciable drift of the airship when preparing to load or 
unload, or while performing its maneuvers. 
Whether the airship is a rigid frame-fabric gas envelope as shown in FIG. 4 
or an all-fabric gas envelope as shown in FIG. 7, gas-containing envelope 
10 may house gas bags 30 fitted therein. Gas bags 30 are adapted to 
contain the lighter-than-air gas, such as helium, to provide the buoyancy 
for lifting the airship. The airship's ascent and descent is governed by 
manipulating the effective density of the gas contained by bags 30 and 
suitable means are included in the airship to accomplish this. 
Accordingly, envelope 10 may be formed with airtight outer skin 32 and 
connected to a source of air or other suitable "heavy" gas (hereinafter 
referred to as air) by umbilical cord 34. Airship descent is effected by 
forcing the air through conduit 34 into outer skin 32. The pressure 
generated by the introduced air compresses gas bags 30 to increase the 
effective density of the lighter-then-air gas in the bags. Additional 
ballast is also provided by the weight of the air. The buoyancy of the 
airship is thereby reduced, causing a loss in altitude. Alternatively, 
airtight bags 31 may be provided within envelope 10 for receiving the air 
through branches of conduit 34 as shown in FIG. 5. This is particularly 
useful in maintaining control of the airship despite any damage which may 
have been suffered by the outer skin. Likewise, when ascent is desired, 
the air is evacuated from envelope 10, or air bags 31, to relieve the 
pressure on gas bags 30 and to release the air ballast. The gas within gas 
bags 30 expands, thereby reducing the effective density of that gas to 
increase buoyancy of the airship. 
In normal operation, gondola 16 is positioned substantially mid-way under 
the belly of the gas envelope to maintain the airship in substantially 
horizontal equilibrium during flight. The airship is driven by propulsion 
means 28 which can be either a simple propeller engine or turbopropeller 
engine. However, it will be understood that gondola 16 may be positioned 
anywhere along member 12 for balance such as when additional propulsion 
devices 60 are mounted to envelope 10, as hereinafter described. 
When the airship according to the present invention has reached its 
destination, gondola 16 may be moved laterally along structural/track 
member 12 toward the airship's nose by positioning means 35. As the 
gondola travels along track member 12, the longitudinal axis of 
gas-containing envelope 10 rotates towards a substantially vertical 
orientation. According to one aspect of the present invention, positioning 
means 35 is connected to gondola 16 to govern its position along 
structural/track member 12. Positioning means 35 may comprise cable 36 and 
winch means 38. Cable 36 may be conveniently affixed to envelope 10 such 
as by attachment to the two ends of track member 12. Furthermore, cable 36 
may be substantially taut to prevent drift of gondola 16 vis-a-vis track 
member 12. 
Winch means 38 acts on cable 36 to pull gondola 16 along member 12 via 
mounting means 18 which may comprise a combination of roller means 24 and 
axle means 24a. As gondola 16 nears the nose of gas-containing envelope 
10, mounting means 18 allows pivoting of gondola 16 about its point of 
contact on member 12 such that gondola 16 remains substantially 
horizontal. In operation, as gondola 16 moves along structural/track 
member 12 via mounting means 18, the action of the shifting positions of 
the gondola's weight, which may be represented as a point load acting on 
member 12, causes the gas-containing envelope 10 to rotate its 
longitudinal axis continuously until the gondola reaches the section of 
member 12 adjacent the nose at which time the longitudinal axis is 
substantially vertical. 
According to another aspect of the present invention, positioning means 35 
may comprise non-slip interface between roller means 24 and flanges 20 
having a non-slip interface therebetween which may be in the form of 
cooperating teeth formed on both roller means 24 and the upper surfaces of 
each flange 20 as shown in FIG. 9c. Alternatively, positioning means 35 
may comprise a high friction roller-flange interface such as by rubberized 
roller means 24 abutting a rougnened upper surface of each flange 20. 
According to either embodiment, roller means 24 may be rotated by any 
convenient drive means 50. Drive means 50 may comprise either a 
conventional chain-drive motor means 52-54 which rotates roller means 24 
as shown in FIG. 9c, or it may be a direct drive motor connected directly 
to roller means 24. 
FIGS. 7 and 8 depict another aspect of the present invention in which 
gas-containing envelope 10 may be provided with two structural/track 
members 12 and gondola 16 is formed with multiple support members 40, each 
provided with a mounting assembly 18, as described above with reference to 
FIGS. 9a-9d, for mounting the gondola to the structural/track members. 
This is particularly useful for large capacity airships which can 
accommodate heavy cargo. Advantageously, the gondola may be provided with 
four support members 40 on the two structural/track members to prevent any 
substantial forward-to-aft or side-to-side pitching of the gondola due to 
gusting winds etc. during flight. 
In operation, the gondola rides below the belly of the gas envelope as in a 
common dirigible or blimp such that the longitudinal axis of the 
gas-containing envelope 10 is generally parallel to the ground. Should the 
airship encounter high winds, the gondola may be moved forward or backward 
of the normal equilibrium point to give the airship an angle of attack, 
negative or positive with respect to air flow to enhance stability during 
flight. 
The airship according to the present invention is particularly adapted for 
convenient refueling, loading and unloading at points of origin and 
ultimate destination, especially where such points are inaccessible by 
other conventional transport means. The gondola is brought forward to the 
nose of the airship, thereby rotating the longitudinal axis of the gas 
envelope to a substantially vertical orientation as shown in FIG. 2. With 
the gondola so positioned, the helium gas bags can be compressed by the 
introduction of air through umbilical cord 34, causing the airship to 
descend. 
Alternatively, descent of the airship can also be effected by allowing the 
lighter-than-air gas to escape from gas bags 30. Accordingly, bleeding 
means which may be in the form of a remote controlled release valve (not 
shown) or second umbilical cord assembly 58 (shown in FIG. 7 connected to 
gondola 16) for controlling the quantity of gas in gas bags 30. This 
procedure for descent is particularly useful when gas envelope 10 and/or 
air bags 31 are damaged whereby altitude control would otherwise be lost, 
or when an emergency arises and rapid descent must be effected. 
Furthermore, this bleeding means can be utilized in reverse for filling 
gas bags 30. 
As the airship is descending for a landing in accordance with one of the 
above-described procedures, or in accordance with one of the hereinafter 
described features, gondola 16 may be landed directly on the ground or 
adjacent a loading platform by utilizing propulsion means 28 in 
conjunction with the ailerons and elevators provided on stabilizer 
assembly 14 to guide the airship to its proper landing position. This 
permits a simple method of landing the airship at a site of limited area, 
whereby a tie-line may be lowered to a landing crew which can have the 
airship pulled down to its proper landing position. Once in landing 
position, the airship can be anchored or suitably tied down, especially as 
hereinafter described, for loading, unloading or refueling. Thus, 
passengers and/or cargo may be loaded or unloaded directly onto the 
gondola without necessitating additional equipment such as lowering and 
hoisting winches or shuttle craft. Furthermore, the present invention 
obviates the need for intermediate storage facilities and minimizes the 
necessity for subsequent transporting when used for shipping cargo. 
As a further feature of the present invention, when the airship is landing 
or has landed and a strong wind prevails at the landing site, the airship 
can be stabilized by utilizing fully rotatable horizontal stabilizers 29, 
and rotatable wings 29a if present, in conjunction with propulsion means 
28 or cut into the wind and stabilize the vertically extending envelope 
with respect to the air flow. In addition, the horizontal stabilizers and 
wings may be oriented with a negative angle of attack to urge the airship 
toward the ground and enhance its stability vis-a-vis the ground. 
Referring now to FIGS. 11 and 12, there is shown a preferred embodiment of 
the present invention which can obviate the need for apparatus for varying 
the effective density of the lighter-than-air gas contained in 
gas-containing envelope 10. According to this aspect of the invention, 
envelope 10 is provided with at least one additional propulsion means 
(indicated by reference numeral 60) mounted thereto such that it provides 
propulsion at a substantially constant orientation with respect to the 
longitudinal axis of envelope 10. Additional propulsion means 60 may 
therefore be utilized to drive this vehicle during flight. More 
importantly, and of most significance here, additional propulsion means 60 
may be used to facilitate descent and touchdown of the vehicle, especially 
after a flight when the vehicle has greater buoyancy due to the loss in 
weight of expended fuel. 
Accordingly, once the desired landing site has been reached, the forward 
drive imparted by both propulsion means 60 and 28 is substantially ceased. 
Thereafter, the airship is brought into its landing configuration, as 
described more fully hereinbefore, wherein the longitudinal axis of 
envelope 10 is in a substantially vertical orientation. Using propulsion 
means 28 when necessary for maneuvering during descent and ascent, as 
previously described, the airship may be driven towards the ground by 
propulsion means 60 in conjunction with tail wing assembly 14 for 
guidance, as well as wings 29a when employed. Thus, the need for a 
plurality of air bags 31, along with the pumping equipment and conduits 
described above with reference to FIGS. 5-7, or any other apparatus for 
reducing the effective density of the lighter-than-air gas contained 
within envelope 10, may be obviated, since propulsion means 60 furnishes 
the necessary impetus for bringing the airship home. Furthermore, 
propulsion means 60 may be continuously operated to keep the airship down 
when, for example, it is not desirable or it is impossible to anchor the 
airship. 
Likewise, propulsion means 60 may be utilized for takeoff and ascent of the 
airship, especially after it has been loaded with cargo and passengers and 
re-fueled, when the airship is at its heaviest. To this end, additional 
propulsion means 60 are provided with means for reversing its thrust to 
change the direction of the propulsion thrust. Thus, for example, when 
propulsion means 60 comprises a propeller engine, it may be provided with 
reversible pitch propeller means for completely reversing the thrust 
generated thereby. Accordingly, once the airship is ready for take-off, 
the thrust of additional propulsion means 60 is reversed, vis-a-vis that 
provided during landing, and the airship, with guidance from tail assembly 
14 and wings 29a, will be propelled upwardly. Once airborne, envelope 10 
can be re-oriented to a generally horizontal configuration and thereafter 
conduct normal in-flight operation. 
For complete safety, however, it may not be adequate to rely upon a single 
additional propulsion device for ascent and descent capability. Therefore, 
it may still be necessary to provide some emergency device for controlling 
the effective density of the lighter-than-air gas contained in envelope 
10. In addition, means for releasing lighter-than-air gas from envelope 
10, such as bleeding means 58 described hereinbefore, may be included to 
provide descent capability in an emergency. Furthermore, more than one 
additional propulsion devices 60 may be mounted to envelope 10 for 
additional safety means and/or, as hereinafter described, for additional 
thrust. 
Referring therefore to FIGS. 13 and 14, there are shown, preferred 
embodiments of the present invention which include, respectively, two and 
three additional propulsion devices, 60a and 60b, respectively. 
Furthermore, individual control over each separate propulsion device will 
provide optimum stability of and control over the flight path of the 
airship during descent and ascent or forward flight in turbulence. 
Additional propulsion means 60 offer a further advantage when the airship 
has wings 29a (even if such wings are not rotatably mounted to the 
airship), since, after loading and refueling, the airship may not 
literally be "lighter-than-air". Accordingly, additional propulsion means 
60 may be employed to lift the airship off the ground. Once the airship is 
airborne, it may be maintained aloft, in flight, through the lift provided 
by wings 29a as the vehicle is driven forward by the propulsion devices. 
Thus, the airship is capable of completely vertical take-off (for example, 
from areas of limited access, as discussed hereinbefore) yet of 
maneuvering substantially like a lighter-than-air vehicle when fully 
loaded and re-fueled. 
Referring now to FIGS. 16 and 18, there are shown embodiments of the 
present invention, which include additional propulsion devices mounted to 
rotatable horizontal stabilizers 29 and, when used, rotatable wings 29a, 
with additional propulsion devices 90 mounted to horizontal stabilizers 29 
and propulsion devices 92 mounted to wings 29a when used. In addition to 
providing in flight forward thrust and vertical thrust capability for use 
in ascent and descent, when desired, propulsion devices 90 and 92 enable 
additional stability capability when the vertically extending airship is 
anchored and high winds are encountered. To this end, stabilizers 29 may 
be rotated to a generally horizontal orientation, or generally parallel to 
the wind flow, as described hereinbefore, with propulsion devices 90 
running to provide thrust generally opposed to the wind direction. Thus, 
gas envelope 10 can be maintained in a generally vertical orientation to 
prevent damage to the airship by, for example, excessive deflection of 
envelope 10 (as measured by angle .alpha., more than about 30.degree. or 
40.degree.) which may strain the coupling means between gondola 16 and 
envelope 10 or propel envelope 10 into some nearby object which may pierce 
it. 
Similarly, when the airship is being landed in windy conditions, 
stabilizers 29 and propulsion devices 90 may be directed so as to oppose 
the wind direction to assist controlling the descent (or ascent during 
take-off) of the airship during landing maneuvers and guiding it to 
touchdown. To this end, and when the airship includes rotatable wings 29a, 
additional propulsion devices 92 may advantageously be provided thereon to 
allow further control of the airship during ascent and descent as well as 
of envelope 10 when the airship is anchored, substantially as described 
above with reference to propulsion devices 90. However, where the wind 
conditions at the landing site are not of concern, propulsion devices 90, 
and 92 when provided, may be used to provide vertical thrust for 
supplementing additional propulsion devices 60 (or in place of devices 60 
if none have been provided) to provide the vertical thrust for ascent and 
descent, as described hereinbefore. 
According to another aspect of the present invention, the airship may be 
more conveniently and safely anchored than currently used airships. 
Conventional lighter-than-air airships are anchored in a generally 
horizontal orientation with the nose (bow) of the gas envelope rotatably 
attached to a tall pole, as shown generally in FIG. 15. In addition, a 
castor may be attached to the bottom of the gondola (which is rigidly 
attached to the gas envelope) such that the entire airship may be freely 
rotatable about the pole and move under the influence of prevailing winds. 
Thus, a substantially large land area is required to allow such airships 
to rotate 360.degree. around the swivel or pivot point to accommodate all 
wind conditions. 
However, in a particularly useful embodiment of the present invention, 
means are provided for securely and safely anchoring the airship at a 
landing site of limited area. Accordingly, attachment means 70 may be 
provided on gondola 16, substantially at the front thereof for pivotal 
attachment to stanchion 72 which is firmly secured to the ground, as shown 
in FIG. 16. Thus, when the airship is brought into a vertical orientation 
for landing, as described hereinbefore, the airship may be anchored to 
stanchion 72 on the ground by attachment means 70. Thereafter, positioning 
means 35 may be left slack to enable vertically extending gas envelope 10 
to move or rotate (as indicated by arrow 82) through any angle .alpha. 
under the influence of prevailing winds (indicated by the arrows 80). 
Accordingly, an airship including this feature of the present invention can 
be anchored to the ground so as to be substantially freely rotatable about 
stanchion 72, yet allowing vertical angular movement of envelope 10 with 
respect to gondola 16. The airship is therefore provided with sufficient 
"give" to yield to prevailing winds for preventing damage thereto while 
anchored. As here preferably embodied, roller means 73 (advantageously a 
castor) may be provided near or at the back end of gondola 16 to provide a 
second support point on gondola 16 such that the back end of the gondola 
can swing around stanchion 72 together with envelope 10 as a unit. Thus, 
stanchion 72 is shorter than currently used anchoring poles for strength 
and low cost. 
Another preferred embodiment of anchoring means is shown in FIG. 17. 
According to this embodiment, the airship includes anchoring structure 74 
secured to the bottom of gondola 16, generally at its mid-section or, 
preferably, at its center of gravity. Anchoring structure 74 is 
advantageously provided with mounting plate 76 adapted for secure 
engagement to a suitable anchor plate 78 secured to the ground. Anchoring 
structure 74, secured through mounting plate 76 and anchor plate 78 is 
rotatable with respect to gondola 16 and the ground. Accordingly, when 
mounting plate 76 and anchor plate 78 are coupled, the entire airship is 
capable of rotating or swiveling about the point to which anchor plate 78 
is secured to the ground. In addition, with positioning means 35 
maintained slack, the airship is provided with sufficient vertical angular 
yield capability to avoid being damaged by strong winds while the airship 
is anchored. 
Advantageously, mounting plate 76 includes an electromagnet operable from 
the gondola, which is capable of generating a strong attractive force to 
ferromagnetic anchor plate 78. Accordingly, when the airship has 
descended, as described hereinbefore, the electromagnet may be energized 
to attract the airship to anchor plate 78. Thereafter, plates 76 and 78 
may be clamped together by any conventional clamping means to provide a 
safety coupling between plates 76 and 78. For ascent, the clamps are 
removed and the electromagnet de-activated, and the airship may ascent as 
described hereinbefore. As here preferably embodied, mounting plate 76 is 
rotatable with respect to gondola in order that the airship may be safely 
anchored (as discussed immediately above) to a simple steel plate secured 
to the ground, either as a standard procedure or during an emergency. 
Advantageously, and as here preferably embodied, by utilizing propulsion 
devices 90 and/or 92, the axis of envelope 10 is maintained at a small 
angle with respect to vertical (i.e. .alpha. ranges from about 5.degree. 
to 15.degree.) in order that the airship will more easily swivel around 
stanchion 72, or anchoring structure 78, under the influence of varying 
wind directions. Thus, with the preinclined angular orientation of 
envelope 10, it acts somewhat like a weather vane to accommodate changes 
in wind direction, thereby significantly lessening any possibility of 
straining the airship under such conditions. 
Those skilled in the art will recognize that certain changes or 
modifications may be made in the structures described above, without 
departing from the scope and spirit of the invention as defined in the 
appended claims. For example, more than three additional propulsion 
devices 60 may be provided on gas-containing envelope 10. Thus, as shown 
in FIG. 18, several groups, or longitudinally disposed tier-like 
arrangement, of such additional propulsion devices (each indicated by 
reference numeral 60) may be mounted to envelope 10 at, for example, about 
one-quarter, one-half and three-quarters the way longitudinally along the 
exterior of the envelope to provide substantial forward thrust when the 
axis of envelope 10 is horizontally oriented and substantial downward and 
upward thrust when the axis is vertically oriented. In addition, when 
either propulsion device 90 or 92, or both, are provided and their 
corresponding mounting structures (stabilizers 29 and wings 29a) are 
rotatably mounted to gas-containing member 10, these structures can be 
oriented at various angles with respect to the longitudinal axis to vary 
the direction of thrust generated by these devices for enabling controlled 
maneuverability of the airship, especially when descending and ascending 
to facilitate accurate landing and safe take-off under windy conditions. 
Accordingly, the invention in its broader aspects is not limited to the 
specific embodiments herein shown and described, but variations may be 
made therefrom within the scope of the accompanying claims, without 
departing from the principles of the invention and without sacrificing its 
principal advantages.