US20080264952A1 - Envelope For Lighter-Than-Air Aircraft - Google Patents
Envelope For Lighter-Than-Air Aircraft Download PDFInfo
- Publication number
- US20080264952A1 US20080264952A1 US11/741,280 US74128007A US2008264952A1 US 20080264952 A1 US20080264952 A1 US 20080264952A1 US 74128007 A US74128007 A US 74128007A US 2008264952 A1 US2008264952 A1 US 2008264952A1
- Authority
- US
- United States
- Prior art keywords
- hemisphere
- envelope
- shell
- equatorial
- equatorial radii
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64B—LIGHTER-THAN AIR AIRCRAFT
- B64B1/00—Lighter-than-air aircraft
- B64B1/06—Rigid airships; Semi-rigid airships
- B64B1/14—Outer covering
Definitions
- Lighter-than-air aircraft take many forms and have a variety of uses.
- Primary uses for unmanned high altitude lighter-than-air aircraft are for surveillance and communications. Often, it is desirable that these aircraft maintain their position, or station keep.
- FIG. 1 is a perspective view of the envelope of the present invention.
- FIG. 2 is a side elevation of the envelope of the present invention.
- FIG. 3 is a top elevation of the envelope of the present invention.
- FIG. 4 is a front elevation of the envelope of the present invention.
- FIG. 5 is an exploded view of the side elevation of FIG. 2 .
- FIGS. 1-4 illustrates envelope 2 for holding gas in a lighter-than-air aircraft.
- Envelope 2 includes a shell 4 .
- Shell 4 has an upper hemisphere 6 and a lower hemisphere 8 divided by equator 10 .
- Upper hemisphere 6 has the shape of a hemisphere of a generally oblate spheroid defined by equatorial radii 12 , 14 and polar radius 16 .
- polar radius 16 is less than equatorial radii 12 , 14 and equatorial radii 12 , 14 are equal to one another.
- Upper hemisphere 6 may be truly oblate, or may deviate from truly oblate. In one embodiment, upper hemisphere 6 deviates from truly oblate with one equatorial radius 12 being longer than the other equatorial radius 14 .
- the ratio of the smaller equatorial radius 14 to the larger equatorial radius 12 is between 0.75 and 1.
- the ratio of the smaller equatorial radius 14 to the larger equatorial radius 12 may be 0.9.
- a ratio in the range of between 0.75 and 1 is defined to be about equal.
- upper hemisphere 6 deviates from truly oblate by extending beyond the boundaries of a perfect oblate spheroid hemisphere, as best seen in FIGS. 3 and 4 .
- the dashed lines represent the boundaries of a generally oblate spheroid with one equatorial radius 12 longer than the other equatorial radius 14 . It can be seen that, although the boundaries of shell 4 do not exactly match the boundaries of the oblate spheroid, the boundaries are substantially close.
- Lower hemisphere 8 has the shape of a hemisphere of a generally oblate spheroid defined by equatorial radii 18 , 20 and polar radius 22 . Similar to upper hemisphere 6 , lower hemisphere 8 is generally oblate and may not be exactly oblate. Additionally, equatorial radii 12 , 14 of upper hemisphere 6 are equal to the equatorial radii 18 , 20 of lower hemisphere 8 . Lower hemisphere 8 is inverted compared to upper hemisphere 6 and is joined with upper hemisphere 6 at their respective equators 10 .
- the volume of upper hemisphere 6 is greater than the volume of lower hemisphere 8 .
- the ratio of the volume of upper hemisphere 6 to the volume of lower hemisphere 8 is between 1.2 and 4.
- the ratio of the volume of upper hemisphere 6 to the volume of lower hemisphere 8 may be 2.3.
- the diameter of shell 4 may be represented by doubling an equatorial radius 12 , 14 , 18 , 20 .
- the height of shell 4 may be represented by adding the polar radius 16 of upper hemisphere 6 with the polar radius of lower hemisphere 8 .
- the height of shell 4 is less than the diameter of shell 4 at the joined equators 10 .
- the ratio of the diameter of shell 4 to the height of shell 4 is between 2.5 and 5.
- the ratio of the diameter of shell 4 to the height of shell 4 may be 3.3.
- an angle of shell 4 may be calculated from equatorial radii 12 , 14 , 18 , 20 and polar radii 16 , 22 .
- the angle of the upper hemisphere is equal to the inverse tangent of polar radius 16 divided by one of the equatorial radii 12 , 14 .
- the angle of the lower hemisphere is equal to the inverse tangent of polar radius 22 divided by one of the equatorial radii 18 , 20 . Adding the angles of the upper and lower hemispheres together, yields the angle of shell 4 .
- the angle of shell 4 is less than or equal to 40 degrees.
- envelope 2 may be alternatively described with reference to a cross section of shell 4 traversing the upper and lower hemispheres.
- the cross section includes two ellipse halves joined at their major axes.
- FIG. 5 best illustrates this description.
- One half of an ellipse 24 defines the shape of upper hemisphere 6 .
- One half of another ellipse 26 defines the shape of lower hemisphere 8 .
- Each of these half ellipses 24 , 26 is divided along its major axis 28 , 30 .
- the major axes 28 , 30 of the ellipses 24 , 26 are equal, the semi-minor axes 32 , 34 of the ellipses are unequal, and the ellipse 24 , 26 halves are joined at their major axes 28 , 30 .
- the ratio of the volume of upper hemisphere 6 to the volume of lower hemisphere 8 is directly related to the ratio of the semi-minor axis of upper hemisphere 6 to the semi-minor axis of lower hemisphere 8 .
- the semi-minor axis of the upper hemisphere is greater than the semi-minor axis of the lower hemisphere and the ratio of the semi-minor axis of the upper hemisphere to the semi-minor axis of the lower hemisphere is between 1.2 and 4.
- the ratio of the semi-minor axis of upper hemisphere 6 to the semi-minor axis of lower hemisphere 8 may be 2.3.
- the semi-major axes, one half of the major axes 28 , 30 are greater than the sum of the semi-minor axes 32 , 34 .
- the ratio of the semi-major axes to the sum of the semi-minor axes is between 2.5 and 5.
- the ratio of the semi-major axes to the sum of the semi-minor axes may be 3.3.
- Shell 4 may be further defined with reference to a cross section through the equator of shell 4 .
- This cross section is generally elliptical.
- the generally elliptical cross section is defined by a major axis and a minor axis and the ratio of the minor axis to the major axis is between 0.75 and 1.
- the ratio of the minor axis to the major axis may be 0.9.
- the present invention is greatly advantageous over previous high altitude envelope solutions as it reduces drag, enabling a lighter-than-air aircraft using this envelope to maintain its position for a longer period of time, maneuver better, and transit longer distances than has been possible with other envelope designs.
Abstract
An envelope is disclosed for holding gas in a lighter-than-air aircraft. The envelope includes a shell having upper and lower hemispheres. The upper hemisphere has the shape of a hemisphere of a generally oblate spheroid defined by equatorial radii and a polar radius. The lower hemisphere has the shape of a hemisphere of a generally oblate spheroid defined by equatorial radii and a polar radius. The lower hemisphere is inverted compared to the upper hemisphere. The equatorial radii of the upper hemisphere are equal to the equatorial radii of the lower hemisphere. The upper hemisphere is joined with the lower hemisphere at their respective equators. The volume of the upper hemisphere is greater than the volume of the lower hemisphere. The height of the shell is less than the diameter of the shell at the joined equators.
Description
- Lighter-than-air aircraft take many forms and have a variety of uses. Primary uses for unmanned high altitude lighter-than-air aircraft are for surveillance and communications. Often, it is desirable that these aircraft maintain their position, or station keep.
- Traditionally, these high altitude aircraft fly below 70,000 feet. It would be greatly advantageous to fly above 70,000 feet to be above atmospheric turbulence and disruptive weather, and to deconflict from commercial, private, and military fixed wing aircraft. However, at altitudes above 70,000 feet, strong winds are present. In order to station keep in these strong winds, it is highly useful for the aircraft to have a low aerodynamic drag.
-
FIG. 1 is a perspective view of the envelope of the present invention. -
FIG. 2 is a side elevation of the envelope of the present invention. -
FIG. 3 is a top elevation of the envelope of the present invention. -
FIG. 4 is a front elevation of the envelope of the present invention. -
FIG. 5 is an exploded view of the side elevation ofFIG. 2 . -
FIGS. 1-4 illustratesenvelope 2 for holding gas in a lighter-than-air aircraft.Envelope 2 includes ashell 4.Shell 4 has anupper hemisphere 6 and alower hemisphere 8 divided byequator 10. -
Upper hemisphere 6 has the shape of a hemisphere of a generally oblate spheroid defined byequatorial radii polar radius 16. In an oblate spheroid,polar radius 16 is less thanequatorial radii equatorial radii Upper hemisphere 6 may be truly oblate, or may deviate from truly oblate. In one embodiment,upper hemisphere 6 deviates from truly oblate with oneequatorial radius 12 being longer than the otherequatorial radius 14. In one embodiment, the ratio of the smallerequatorial radius 14 to the largerequatorial radius 12 is between 0.75 and 1. For example, the ratio of the smallerequatorial radius 14 to the largerequatorial radius 12 may be 0.9. In the context of the present invention, a ratio in the range of between 0.75 and 1 is defined to be about equal. - In another embodiment,
upper hemisphere 6 deviates from truly oblate by extending beyond the boundaries of a perfect oblate spheroid hemisphere, as best seen inFIGS. 3 and 4 . The dashed lines represent the boundaries of a generally oblate spheroid with oneequatorial radius 12 longer than the otherequatorial radius 14. It can be seen that, although the boundaries ofshell 4 do not exactly match the boundaries of the oblate spheroid, the boundaries are substantially close. -
Lower hemisphere 8 has the shape of a hemisphere of a generally oblate spheroid defined byequatorial radii polar radius 22. Similar toupper hemisphere 6,lower hemisphere 8 is generally oblate and may not be exactly oblate. Additionally,equatorial radii upper hemisphere 6 are equal to theequatorial radii lower hemisphere 8.Lower hemisphere 8 is inverted compared toupper hemisphere 6 and is joined withupper hemisphere 6 at theirrespective equators 10. - The volume of one hemisphere of an oblate spheroid may be represented by the equation V=4/6 πabc, where a, b, and c are the equatorial radii and the polar radius. In the present invention, the volume of
upper hemisphere 6 is greater than the volume oflower hemisphere 8. In one embodiment, the ratio of the volume ofupper hemisphere 6 to the volume oflower hemisphere 8 is between 1.2 and 4. For example, the ratio of the volume ofupper hemisphere 6 to the volume oflower hemisphere 8 may be 2.3. - The diameter of
shell 4 may be represented by doubling anequatorial radius shell 4 may be represented by adding thepolar radius 16 ofupper hemisphere 6 with the polar radius oflower hemisphere 8. In one embodiment, the height ofshell 4 is less than the diameter ofshell 4 at the joinedequators 10. In one embodiment, the ratio of the diameter ofshell 4 to the height ofshell 4 is between 2.5 and 5. For example, the ratio of the diameter ofshell 4 to the height ofshell 4 may be 3.3. - Furthermore, an angle of
shell 4 may be calculated fromequatorial radii polar radii polar radius 16 divided by one of theequatorial radii polar radius 22 divided by one of theequatorial radii shell 4. In one embodiment, the angle ofshell 4 is less than or equal to 40 degrees. - Since upper 6 and lower 8 hemispheres are shaped as generally oblate spheroids,
envelope 2 may be alternatively described with reference to a cross section ofshell 4 traversing the upper and lower hemispheres. In this description, the cross section includes two ellipse halves joined at their major axes.FIG. 5 best illustrates this description. One half of anellipse 24 defines the shape ofupper hemisphere 6. One half of anotherellipse 26 defines the shape oflower hemisphere 8. Each of thesehalf ellipses major axis major axes ellipses semi-minor axes ellipse major axes - Since upper 6 and lower 8 hemispheres are shaped as generally oblate spheroids and the
equatorial radii equatorial radii upper hemisphere 6 to the volume oflower hemisphere 8 is directly related to the ratio of the semi-minor axis ofupper hemisphere 6 to the semi-minor axis oflower hemisphere 8. Therefore, in one embodiment the semi-minor axis of the upper hemisphere is greater than the semi-minor axis of the lower hemisphere and the ratio of the semi-minor axis of the upper hemisphere to the semi-minor axis of the lower hemisphere is between 1.2 and 4. For example, the ratio of the semi-minor axis ofupper hemisphere 6 to the semi-minor axis oflower hemisphere 8 may be 2.3. - In a further embodiment, the semi-major axes, one half of the
major axes semi-minor axes -
Shell 4 may be further defined with reference to a cross section through the equator ofshell 4. This cross section is generally elliptical. In one embodiment, the generally elliptical cross section is defined by a major axis and a minor axis and the ratio of the minor axis to the major axis is between 0.75 and 1. For example, the ratio of the minor axis to the major axis may be 0.9. - The present invention is greatly advantageous over previous high altitude envelope solutions as it reduces drag, enabling a lighter-than-air aircraft using this envelope to maintain its position for a longer period of time, maneuver better, and transit longer distances than has been possible with other envelope designs.
- The foregoing description is only illustrative of the invention. Various alternatives, modifications, and variances can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention embraces all such alternatives, modifications, and variances that fall within the scope of the described invention.
Claims (24)
1. An envelope for holding gas in a lighter-than-air aircraft, the envelope comprising:
a shell including
an upper hemisphere having the shape of a hemisphere of a first generally oblate spheroid defined by first and second equatorial radii and a polar radius and
a lower hemisphere having the shape of a hemisphere of a second generally oblate spheroid defined by first and second equatorial radii and a polar radius, wherein the lower hemisphere is inverted compared to the upper hemisphere, the equatorial radii of the upper hemisphere are equal to the equatorial radii of the lower hemisphere, and the upper hemisphere is joined with the lower hemisphere at their respective equators,
wherein the volume of the upper hemisphere is greater than the volume of the lower hemisphere, and
wherein the height of the shell is less than the diameter of the shell at the joined equators.
2. The envelope of claim 1 wherein the polar radius of the first generally oblate spheroid is less than the equatorial radii of the first generally oblate spheroid and the polar radius of the second generally oblate spheroid is less than the equatorial radii of the second generally oblate spheroid.
3. The envelope of claim 1 wherein the first and second equatorial radii of the first generally oblate spheroid are about equal and the first and second equatorial radii of the second generally oblate spheroid are about equal.
4. The envelope of claim 3 wherein the ratio of the smaller of the first and second equatorial radii of the first generally oblate spheroid to the larger of the first and second equatorial radii of the first generally oblate spheroid is between 0.75 and 1.
5. The envelope of claim 7 wherein the ratio of the smaller of the first and second equatorial radii of the second generally oblate spheroid to the larger of the first and second equatorial radii of the second generally oblate spheroid is between 0.75 and 1.
6. The envelope of claim 1 wherein the ratio of the volume of the upper hemisphere to the volume of the lower hemisphere is between 1.2 and 4.
7. The envelope of claim 1 wherein the ratio of the diameter of the shell to the height of the shell is between 2.5 and 5.
8. The envelope of claim 1 wherein the angle of the shell is less than or equal to 40 degrees.
9. An envelope for holding gas in a lighter-than-air aircraft, the envelope comprising:
a shell generally including
an upper hemisphere having the shape of a hemisphere of an ellipsoid defined by first and second equatorial radii and a polar radius, wherein the first and second equatorial radii are about equal and the polar radius is less than the first and second equatorial radii and
a lower hemisphere having the shape of a hemisphere of an ellipsoid defined by first and second equatorial radii and a polar radius, wherein the first and second equatorial radii are about equal and the polar radius is less than the first and second equatorial radii and less than the polar radius of the upper hemisphere.
10. The envelope of claim 9 wherein the ratio of the smaller of the first and second equatorial radii of the upper hemisphere to the larger of the first and second equatorial radii of the upper hemisphere is between 0.75 and 1.
11. The envelope of claim 9 wherein the ratio of the smaller of the first and second equatorial radii of the lower hemisphere to the larger of the first and second equatorial radii of the lower hemisphere is between 0.75 and 1.
12. The envelope of claim 9 wherein the ratio of the volume of the upper hemisphere to the volume of the lower hemisphere is between 1.2 and 4.
13. The envelope of claim 9 wherein the ratio of the diameter of the shell to the height of the shell is between 2.5 and 5.
14. The envelope of claim 9 wherein the angle of the shell is less than or equal to 40 degrees.
15. An envelope for holding gas in a lighter-than-air aircraft, the envelope comprising:
a generally oblate spheroid shaped shell having upper and lower hemispheres
wherein at least one cross section of the shell traversing the upper and lower hemispheres includes a half of a first ellipse divided along its major axis, defining the shape of the upper hemisphere, and a half of a second ellipse divided along its major axis, defining the shape of the lower hemisphere, wherein the major axes of the ellipses are equal, the semi-minor axes of the ellipses are unequal, and the ellipse halves are joined at their major axes.
16. The envelope of claim 15 wherein the volume of the upper hemisphere is greater than the volume of the lower hemisphere.
17. The envelope of claim 17 wherein the ratio of the volume of the upper hemisphere to the volume of the lower hemisphere is between 1.2 and 4.
18. The envelope of claim 15 wherein the semi-minor axis of the upper hemisphere is greater than the semi-minor axis of the lower hemisphere.
19. The envelope of claim 17 wherein the ratio of the semi-minor axis of the upper hemisphere to the semi-minor axis of the lower hemisphere is between 1.2 and 4.
20. The envelope of claim 15 wherein the semi-major axes are greater than the sum of the semi-minor axes.
21. The envelope of claim 20 wherein the ratio of the semi-major axes to the sum of the semi-minor axes is between 2.5 and 5.
22. The envelope of claim 15 wherein a cross section through the equator of the shell is generally elliptical.
23. The envelope of claim 22 wherein the shape of the generally elliptical cross section is defined by a major axis and a minor axis and the ratio of the minor axis to the major axis is between 0.75 and 1.
24. The envelope of claim 15 wherein the angle of the shell is less than or equal to 40 degrees.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/741,280 US20080264952A1 (en) | 2007-04-27 | 2007-04-27 | Envelope For Lighter-Than-Air Aircraft |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/741,280 US20080264952A1 (en) | 2007-04-27 | 2007-04-27 | Envelope For Lighter-Than-Air Aircraft |
Publications (1)
Publication Number | Publication Date |
---|---|
US20080264952A1 true US20080264952A1 (en) | 2008-10-30 |
Family
ID=39885749
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US11/741,280 Abandoned US20080264952A1 (en) | 2007-04-27 | 2007-04-27 | Envelope For Lighter-Than-Air Aircraft |
Country Status (1)
Country | Link |
---|---|
US (1) | US20080264952A1 (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20130126668A1 (en) * | 2011-11-22 | 2013-05-23 | Thales | Balloon Comprising Photovoltaic Means and a Solar Concentration Device |
US10418505B2 (en) * | 2014-10-30 | 2019-09-17 | International Business Machines Corporation | Aerodynamic solar pods |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US250417A (en) * | 1881-12-06 | Vessel for aerial navigation and machinery for propelling the same | ||
US1120852A (en) * | 1914-06-09 | 1914-12-15 | John Henry Schroeder | Airship. |
US6164589A (en) * | 1999-05-17 | 2000-12-26 | Lockheed Martin Corporation | Centerline landing gear for aerocraft |
US6565037B1 (en) * | 2002-06-04 | 2003-05-20 | Tonkovich Gregory P | Hybrid aircraft and methods of flying |
-
2007
- 2007-04-27 US US11/741,280 patent/US20080264952A1/en not_active Abandoned
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US250417A (en) * | 1881-12-06 | Vessel for aerial navigation and machinery for propelling the same | ||
US1120852A (en) * | 1914-06-09 | 1914-12-15 | John Henry Schroeder | Airship. |
US6164589A (en) * | 1999-05-17 | 2000-12-26 | Lockheed Martin Corporation | Centerline landing gear for aerocraft |
US6565037B1 (en) * | 2002-06-04 | 2003-05-20 | Tonkovich Gregory P | Hybrid aircraft and methods of flying |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20130126668A1 (en) * | 2011-11-22 | 2013-05-23 | Thales | Balloon Comprising Photovoltaic Means and a Solar Concentration Device |
US9650122B2 (en) * | 2011-11-22 | 2017-05-16 | Thales | Balloon comprising photovoltaic means and a solar concentration device |
US10418505B2 (en) * | 2014-10-30 | 2019-09-17 | International Business Machines Corporation | Aerodynamic solar pods |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US10472063B2 (en) | Systems and methods for foldable arms | |
CN105867421B (en) | A kind of unmanned plane paths planning method based on PH curve | |
US9428257B2 (en) | Extended endurance air vehicle | |
US9824596B2 (en) | Unmanned vehicle searches | |
US7624951B1 (en) | Aircraft with antennas mounted on the tops and bottoms of aerodynamic-surface extensions | |
US9352819B2 (en) | Airship pitch trim and directional control system | |
ES2807425T3 (en) | High altitude aircraft wing geometry | |
WO2010143179A1 (en) | Air vehicle | |
WO2011131733A3 (en) | Vertical take-off and landing multimodal, multienvironment, gyropendular craft with compensatory propulsion and fluidic gradient collimation | |
WO2020107846A1 (en) | Stealth large maneuvering target aircraft and control method for stealth large maneuvering target aircraft | |
KR102239444B1 (en) | Real-time Routing Control System for the Map-based Drone Flight and Control method thereof | |
US20080264952A1 (en) | Envelope For Lighter-Than-Air Aircraft | |
US20200031458A1 (en) | Unmanned Aerial Vehicle with Thrust Decoupling, Active Wing Loading, Omnidirectional Lift Control and/or Vibration Management | |
US20160272315A1 (en) | Compound wing vertical takeoff and landing small unmanned aircraft system | |
US6983910B2 (en) | Membrane structure | |
AU2017266853B2 (en) | Systems and methods for lighter-than-air high altitude platforms | |
Van Asares et al. | Design of an unmanned aerial vehicle blimp for indoor applications | |
US20100025534A1 (en) | Envelope For Lighter-Than-Air Aircraft | |
RU2609660C1 (en) | Air taxi | |
US11267555B2 (en) | Methods and unmanned aerial vehicles for longer duration flights | |
CN211178156U (en) | Unmanned drone | |
RU2652373C1 (en) | Aerostat | |
Suvarna et al. | Design methodology of a small unmanned airship with optimized fins | |
RU2652322C1 (en) | Aerostat | |
RU2643306C1 (en) | Aeronautic apparatus |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: NEAR SPACE SYSTEMS, INC., COLORADO Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:CHU, ADAM N.;REEL/FRAME:019222/0819 Effective date: 20070427 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |