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Technology Spotlight: Follow along each day as NAA technology expert Al Robbins posts and comments on one of the >4000 United States patents related to lighter-than-air (LTA).
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  • 09 Dec 2013 2:27 PM | Deleted user

    Todays patent is one of five LTA-related patents issued to Slater.

      “Although "heavy-lift" airships have been proposed for lifting heavy

    and/or bulky objects much like the "sky-crane" helicopter devices,

    conventional airships are not suitable for such applications without

    heavy ballast equipment. Once such airships have delivered their

    payload, the airship would, without the addition of substantial ballast,

    always tend to rise. Accordingly, there is a need for an improved

    airship which is capable of lifting and depositing heavy loads without

    requiring such additional heavy ballast equipment.

          It is therefore an object of the present invention to provide new

    and improved anchoring means for airships containing lighter-than-air

    gas. Another object of the present invention is to provide new and

    improved propulsion means for use either alone or in conjunction

    with the anchoring means.

          It is a further object of the present invention to provide a new and

    improved apparatus for landing and anchoring an airship, which

    enables landing and at least initial anchoring essentially by the pilot

    alone without the need for a ground crew or on-board help.

          It is also an object of the invention to provide a new and improved

    airship having a simple and strong anchoring means, with the airship

    requiring relatively less land area than conventional techniques for

    approach, touchdown and anchoring.

         It is yet a further object of the invention to provide an airship whose

    propulsion system can be located at various positions with respect to

    the longitudinal axis of the gas-containing structure for controlling

    the horizontal trim of the airship.

         It is still another object of the present invention to provide new and

    improved propulsion means for a lighter-than-air airship, enabling

    the airship to lift and deposit heavy loads without requiring additional

    ballast equipment to enable the ship to descend after it is unloaded.”

           ( Line 44 Column 2 through Line 13 Column 3.)

    Slater formed the nearly-forgotten corporation, HOV-AIR-SHIP, Inc.,

    to develop his concept.  Presumably, his Heavy-Lift airship was

    intended to transport cargo plus the huge magnet.

           Saul I. Slater, of New York state, is also credited with nearly 

           twenty patents on electrical devices in the 50's and 60's - 

           perhaps the same individual.

    Note: Claims 20 and 21 involve a propulsion means, but do not mention

    mooring or anchoring. three claims (14, 15 & 16) involve the use of

    directional thrust while mooring. All other claims apply to a magnetic 

    mooring device, as part of Slater’s airship.


    The patent is cited by four later U.S.patents, and five foreign patents.

  • 08 Dec 2013 12:42 PM | Deleted user

    Todays patent is one of Regipa’s seventeen U.S. patents.

    From column 1, Lines 51 through 68:

         “One essential object of the invention is to provide an aerostatic 

    balloon of which the volume can be very large, so as to be capable

    of transporting high loads, and of which the gas-retaining 

    structure can withstand very high overpressures (several hundred


           Accordingly it is an object of the invention to provide a 

    balloon which can be aerostatically steered by varying the gas 


           Another object of the invention is to increase substantially

    the effectiveness of the steering actions (in the vertical direction)

    in order to make possible rapid and well controlled changes in

    level regardless of altitude.

           Another object is to achieve good balloon stability 

    regardless of altitude and in particular at the upper limit.

          Still another object is to make easier the ground-based 

    balloon launching operations.”

    Regipa's patent has already been cited by fifteen

    U.S. patents, plus Canadian, German, Japanese, and

    other international patents.

  • 08 Dec 2013 12:20 PM | Deleted user

    Kraft was a prolific inventor, with roughly ninety patents 

    assigned to Goodyear or The General Tire Company. 

    This is one of his few patents related to Lighter-than-air.

    Neither this earlier "pony blimp" nor Kraft's invention have

    a rudder on top of the envelope. But notice the wide separation

    between its envelope and the supported open car.

         Dirigible aircraft of the non-rigid type as heretofore 

    constructed, are generally provided with control or pilot cars

    suspended by means of a number of wires secured to finger 

    patches distributed over considerable area of the lower surface 

    of the envelope; or by numerous suspension lines disposed 

    circumferentially over top and sides of the envelope. The 

    number of wires necessary to properly suspend loads to be 

    carried present an intricate network of suspension members 

    and the control car must be spaced a considerable distance 

    from the lower surface of the envelope in order to reduce the 

    stresses tending to buckle the aircraft upwardly adjacent to the 

    middle portion. In case gas pressure in the envelope becomes 

    low, there is a strong tendency for its shape to become bowed 

    at the central portion because of the forces exerted by the 

    suspension wires pulling from the ends of the aircraft toward 

    its center. Also the greater the distance between the envelope

    of the aircraft and the control car, the greater will be the 

    impediment to speed, and the more will be the difficulty 

    encountered in steering.”

    NOTE: This is one of Kraft's few patents related to Lighter-than-air.

    In it he emphasizes three key innovations: 

      To simplify construction and rigging; 

      To reduce drag; and 

      To improve steering. 

    N.B. Kraft points out that his invention is particularly useful for the

    small pressure airships known as "Pony Blimps", but that it would 

    also be useful for large airships.

    The USPTO only assigned one of several applicable classifications.

  • 06 Dec 2013 11:57 PM | Deleted user

    Todays patent is one of Dürr’s many U.S. patents assigned to Luftschiffbau Zeppelin.

    My data base includes 31 U.S. patents issued to  Dr. Dürr 

    (Dürr. Durr, or Duerr). Most were assigned to Luftschiffbau Zeppelin.

    You can only search for these older patents (pre 1970’s) by 

    Patent Number or currently assigned classification(s) ) on the USPTO 


    You can find nearly half of them on Google.com/patents under:

      Inventor (Dürr, Durr, or Duerr),

      Exact Phrase (Ludwig Dürr) , or

      Assignee Name (Zeppelin and Luftschiffbau Zeppelin). 

    Perhaps some of our members might be able to tell us how many German patents he held.

           Because of the ship having cars situated underneath its 

    hull or body the lower rudder will have less efficiency than 

    the upper one, both having the same surface and usually the

    same shape. This causes a very undesirable effect on the ships

    horizontal course, as the resistance from the rudder above the

    hull or body will differ from the resistance of the lower rudder, 

    and this will have a rolling effect on the ship as a whole.

         According to my invention I am doing away with these 

    drawbacks by horizontally extending the surface of the lower 

    rudder, so that it is wider than the upper one. Furthermore it 

    may be advisable to also increase the area of the lower rudder 

    by an adequate change in its shape. Also in accordance with

    my invention it may be useful to provide means for always

    giving the lower rudder a wider angle of deviation than the

    upper rudder has at the same time. This for example may be

    attained by making the operating levers of the lower rudder

    shorter than those of the upper rudder while the control wires

    of both rudders are moved over equal distances.”

    NOTE: As chief engineer for Zeppelin throughout the Rigid Airship 

    era, Dr. Durr was responsible for the design and production of the

    vast majority of all the world's rigid airships.

    The USPTO neglected to cite the primary classification -
    244/87 (Rudders and empennage). It might also have cited 

    244/125 (Airship hull construction).

    Consequently, it ignored the purpose of the invention, to reduce 

    unintended rolling force and unwanted torque on the tail surfaces 

    of his huge rigid airships during turns and when operating in 

    cross winds. N.B. The patent addresses only two methods of

    correcting the problem: Increasing the size of the lower rudder,

    and/or increasing the angular displacement of the lower rudder

    compared to that of the upper rudder.

  • 05 Dec 2013 9:29 AM | Deleted user

    Todays patent is one of Badeau’s four airship patents.

         “My invention has two main phases. On the one hand it relates to 

    an improved construction of lighter-than-air vessel including an 

    elongated gas-container, whereby enhanced stability is secured; and 

    on the other hand it relates to improved steering means whereby is 

    attained complete control of the movements of the airship parallel

    to the surface of the earth. While this improved steering means is 

    particularly adapted to navigable lighter-than-air vessels constructed

    for superior stability according to the other phase of the invention, 

    it is by no means limited in its applicability to such air-ships, but may 

    be embodied in any type of vessel designed for navigation of the 

    earth’s atmosphere.”

    NOTE: Despite the title, the USPTO didn't assign any classification 

    which would indicate that the patent applies to airships.

    Badeau's invention incorporates a full-length “propulsion tube” 

    as the prime mover.  (Optional vertical thrusters in separate short tubes

    and multiple horizontal rudders to control the altitude of the airship).

    No mention of how this long tube is constructed or what prevents its 

    collapse. Badeau identifies the optional pivoting wings as horizontal

    rudders. He doesn’t describe or claim the structure needed to connect

    the tunnels, rudders, and the single large buoyant gas cell.

    N.B. The claims emphasize that the primary propellers should be inside
    and near each end of the propeller tube. This is a classic example of 

    Burgess' seven "Common Airship Fallacies".

  • 04 Dec 2013 7:42 AM | Deleted user

    Todays patent is one of Mercier’s fluid control patents.

          “It is known that the distribution of theoretical pressure 

    exerted by a fluid on a stream-lined body having an axis

    aligned or slightly inclined with respect to the general direction

    of relative flow between the body and fluid, is characterized, 

    beginning at the forward end of the body, by:

    (a)A forward zone of dynamic pressure greater than the ambient 
         static pressure of the fluid. The pressure is a maximum at the
         extreme forward point of the body and decreases rearwardly
          to a value equal to the ambient static pressure;

    (b) A depression zone follows the aforementioned forward zone, 

         wherein the static pressure becomes less than the ambient 

          static pressure. The location of the minimum pressure in the

          depression zone depends upon the shape of the body. The 

          said pressure increases rearwardly of the minimum pressure,

          until it reaches a value equal to the ambient static pressure of 

          the surrounding fluid at a location far from the body;

    (c) A rear super-pressure zone much less in intensity than the 

          forward zone a.”


          “The result is an increase of drag, which it has been sought

    to reduce in various ways, without hitherto obtaining a perfectly 

    satisfactory result.

           An object of the invention is to improve the performance of 

    streamlined bodies by increasing the speed thereof for the same 

    energy consumption, or to reduce the amount of energy necessary

    to impart a predetermined speed to the body.”

    NOTE: Mercier does not claim that his drag reduction invention will be 

    useful at large angles-of-attack. Nor does he mention a limiting

    effective angle-of-attack (e.g.< 8 degrees).

    N.B. An airship is the only flying vehicle for which drag is far more

    important than lift.

    Unfortunately, the USPTO neglected to cite:
       244/75.1 (Aircraft control) or 244/96 (Airship control) or,
       244/130 (Aerodynamic resistance reducing).

    The patent is cited by eleven modern patents (only one related to


     3,194,201  Underwater missile,

     3,244,135  Device for controlling ship movement,

     3,425,741  Land vehicle having minimum air drag,

     4,125,083  Drive for submerged floating bodies,

     4,309,172  Ship with improved stern structure,

     4,327,469  Method for mounting ring-shaped construction on ship stern,

     4,395,965  Low drag underwater vehicle utilizing boundary layer suction,

     4,919,066  Hydrodynamic configuration for underwater vehicle,

     5,125,797  Portable water driven high velocity fan,

     5,389,021  Motorboat propeller safety shroud, and

     5,620,153  Light aircraft with inflatable parachute wing propelled by a ducted


  • 03 Dec 2013 8:34 AM | Deleted user

    Todays patent is one of Yost’s twenty U.S. patents.

         Transport by air makes it possible to transfer heavy loads over 

    areas of rugged terrain or bodies of water, or to areas where roads

    have not been built. Heavy loads have been transported by helicopters

    but a limit of practicality is reached with extremely heavy loads

    wherein even large helicopters cannot carry the loads or wherein the

    use of a large helicopter is inconvenient or costly. Balloons are 

    capable of inexpensively lifting loads much heavier than those 

    conveniently carried by helicopters, and in accordance with the 

    present invention heavy pay loads are lifted by balloons and are towed 

    by helicopters which are attached by a tow line to the pay load and 

    provide only a small percentage of the required lift. A preferred form

    of balloon employed for these heavy lifting jobs is supplied with lifting

    gas from a burner which can be regulated to change the net lift or 

    free lift of the balloon.

           In lifting and transporting the heavy loads, the load on the 

    helicopter must be maintained substantially uniform to avoid loss of 

    control of the helicopter. This is accomplished by automatically 

    adjusting the net lift of the balloon so that it applies a constant lift to 

    the pay load, which is a predetermined lift less than the total

    weight of the pay load.”

    NOTE: All ten claims involve a Lighter-Than-Air balloon which 

    buoyantly supports most of a heavy payload; neither assigned classification

    applies to balloons. The USPTO should have included 244/33 (Balloon, captive).

    N.B. None of the claims involve multiple balloons. Helicopters are the 

    only towing (or lifting) machines mentioned in the text or any of the

    claims. The patent does not discuss method or means of releasing the 

    payload after it has been transported to the desired location.

    Cited by:

    3,351,325  Aerial pick-up and delivery system,

    3,946,971  Load lifting system,

    4,498,408  Lifting body for diving, and

    WO 2002042149  Spherical LTA cargo transport system.

  • 02 Dec 2013 6:45 PM | Deleted user

    Todays patent is one of Arnstein’s 31 U.S. patents.

     “According to my invention the girders or ribs of the fins at those

    cross sections of the ship where there is a ring are carried right 

    through this ring to the opposite ring corners there joining the 

    girders or ribs of the oppositely situated fin. Usually there are 

    four fins placed at the ships stern and therefore according to my 

    invention the rings in the stern will be intersected by two pairs 

    of girders connecting the ring corners where as fin ribs join.

    At the points of intersection of these girders they are connected 

    together and the panels which are formed by the ring girders 

    and reinforcing girders are braced so as to constitute together with

    the ring a kind of circular truss. Thereby a perfect reinforcement 

    of the ships stern is attained making certain a secure way of 

    transmitting the air stresses from the fins to the hull structure. It is

    of the highest importance to have to a safe construction in the 

    ships stern where the stresses on the fins and on the rudders and

    elevators attached to them may vary greatly in strength as well as 


    NOTE: Curiously, although the text mentions the rudders and 

    elevators, none of the claims address these control surfaces, their 

    means of attachment or positioning equipment. Perhaps that explains 

    why the USPTO didn’t assign 244/87 (Rudders & empennage).

    The patent is not cited by any modern patents.


  • 01 Dec 2013 10:02 PM | Deleted user

    Todays patent is Schleinitz’ only U.S. patent.

          "It is to be assumed that the cars, adapted to receive the 

    air-ship, are rotatable in the known manner on a turntable, 

    which latter is provided with an extensible pivoted support 

    for the anchoring cable. This support is adapted to prevent the 

    head of the airship from being pressed on the ground by the 

    wind, and also for the purpose of bringing the airship to the 

    correct level so that it can be fastened upon the cars. The cars,

    adapted to receive the airship, are provided with separate 

    supports for the airship, which supports are so arranged that 

    they can easily be adjusted or turned so that while the airship

    is descending no projecting parts would be likely to cause 

    damage. These supports mounted on the cars, carry beds or 

    girths composed of sail-cloth or the like, into which the airship

    is pulled. The anchoring is effected, and the supports,as also 

    the sail-cloth beds, are retained in the raised position by means

    of tension wires or cables.”

    NOTE: This is one of the earliest patents proposing a nose mooring 

    fitting for a rigid airship. Both German manufacturers had avoided 

    mooring-out systems, essentially walking their ships in and out of 

    the hangars, where they were slung from the overhead. 

    N.B.The patent doesn’t indicate that the slings are capable of 

    supporting the entire weight of the ship when there is no lifting gas.

    This patent is cited by three US and one international patent:  

    5,431,359  Docking system for a lighter-than-air vehicle,

    5,497,962  Mooring tower assembly for a lighter-than-air vehicle,

    6,792,872  Balloon car and aerial trolley system, and

    WO 1995026903  A docking system for a lighter-than-air vehicle.

  • 30 Nov 2013 6:54 AM | Deleted user

    Todays patent was Kapferer’s only American LTA patent.

          “Hitherto, the attachment of the fabrics 7, 9, 11 and 12 around

    the cords 17 and 18 has been effected by a lacing comprising  

    a cord passing through a suitable number of metal eyelets fixed 

    to the boltropes of these fabrics.  Further, the internal suspension

    ropes 15 passed through the lower edge by being

    threaded through suitable metal parts.

          Owing to this method of assembling, the lacing eyelets and the 

    metal parts through which the suspension ropes passed, were in 

    contact with the gas in the envelop and were rapidly oxidized,

    and they corroded the lacing cords of the edge of the envelop.

          The present invention has now for its object to remedy these 

    various drawbacks, and it consists substantially in a system of lacing 

    the several fabrics connected to the lower edge of an airship with 

    internal suspension, wherein no medal part is in contact with the 

    gas in the envelope.”

    NOTE: The Astra-Torres, three-lobed blimp was one of the more 

    successful non-rigid airship designs in the early 20th century. 

    Kapferer’s invention was a solution to what was apparently one 

    of its primary failure mechanisms; corrosion caused by exposure 

    to hydrogen, or other lifting gases.  N.B. The patent doesn’t

    mention any means of sealing the junctions between the various 

    envelope sections.

    The USPTO might also have assigned:

    244/125 (Airship hull construction), and

    244/126 (Airship skin construction).

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