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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).
  • 09 Nov 2013 4:59 AM | Deleted user

    Todays patent is one of Boerner’s thirteen U.S. Patents.

         “The present system employs primarily, in air-ship navigation, 

    three gases confined in three chambers for the purpose of securing 

    buoyancy, safety and ballast control. As an example, hydrogen 

    may be used for the lifting gas, as insulating gas nitrogen may be 

    used, and for the purpose of the practical utilization of said lifting 

    gas, an air-chamber is used whose capacity depends on the height

    of ascent which is had in view. With these means, by the use of the

    propulsive force for vertical steering, for the purpose of equalizing 

    the disturbance of the balance, from whatever cause this originates, 

    the loss of gas by changes in atmospheric pressure and variations 

    in the atmospheric temperature are avoided: also the use of ballast 

    becomes superfluous. By the present airship system, longitudinal 

    and transverse single  balloons holding different gases are primarily 

    provided, under cover of a common envelop. The longitudinal rows 

    are separated into sections, so that the three transverse balloons form

    one section. The individual balloons are arranged in quadrangular 

    form in order to avoid the intermediate spaces which occur, as such,

    in cylindrical balloons and are bound together at their angles by

    cords or rings and bolts, so that the whole balloon system appears 

    as a unitary body.

    NOTE: The USPTO neglected to cite any classification directly 

    related to airships, e.g. 244/128 (Airship gas cell construction and 

    arrangement), the primary innovation claimed by the patent. 

    Despite this omission, the patent is cited by two modern patents: 

     3,185,411  Multiple celled airship, and

     4,773,617   Lighter-than-air craft.  

  • 08 Nov 2013 8:17 AM | Deleted user

    Todays patent is one of 43 patents issued to Upson during his

    long aeronautical career.

         “The particular embodiment of my invention herein illustrated

    consists of an elongated cigar-shape envelope, with the particular

    internal tackle or cable arrangement telescoping diaphragm 

    connection of gas with special arrangement of ballonet diaphragm, 

    but with the longitudinal girders at the outside of the hull

    connected one to the other by sheet metal. In general, the 

    inventions hereinafter described apply in particular to what may 

    be generally termed an all-metal dirigible, particular reference 

    being to the metal envelope.

    NOTE: This patent was not assigned to Goodyear Tire and Rubber 

    or his subsequent Aircraft Development Corporation; it’s the only

    application Upson filed while he lived in Brooklyn, New York.

    Despite his choice of title, Upson claims his invention applies
    to both rigid and semi-rigid airships. Both the "complete" and the
    “substantially complete” envelopes consist of gas-tight metal sheets.

    This patent is cited by three modern patents:

     3,871,603  Fin attachment for tethered balloon structures,

     4,208,027  Gradation of skin thickness on metal-clad airship hulls, and

     4,265,418  Elongated inflatable structures for flying device bodies.

  • 07 Nov 2013 7:03 AM | Deleted user

    Todays patent is Eubank’s only U.S. Patent.

         “This invention relates to captive observation-balloon apparatus; 

    and my object is to produce an apparatus of this character by which 

    people can be safely elevated to a great height and brought back to 

    earth with perfect safety without regard to weather conditions. 

    Apparatus of this character will be found of great value as a

    temporary observatory for scientific and war purposes, as well as an

    attraction which the great mass of the public would be glad 

    to patronize.”

    NOTE: Three of the patent's four claims relate to an assembly which 

    includes a collapsed parachute. (No discussion regarding when or why

    the parachute might be deployed.)

    The fourth claim, which doesn’t mention the parachute, is the only 

    claim which discusses the mooring arrangement, or the method of 

    raising and lowering the balloon.  

    All four begin “In an apparatus of the character described.

    The text describes a quadrilateral system of winch-controlled tether lines 

    attach to a single point on a captive balloon (such as a high-moored 


    The USPTO didn’t assign 244/115 (Mooring devices); it did assign 

    four classifications:

     244/32 (Balloon, with parachute),

     244/33 (Balloon, captive),

     244/98 (Gas bag inflation) and

     254/318 Class 254 consists of Implements or apparatus for applying

                   pushing or pulling force.

    This patent is cited by six modern patents:

     3,005,604 Tethered balloon control,

     3,045,952 Antenna support structure,

     3,053,481 Tether station,

     3,128,969 Cartridge inflated balloon

     5,080,302 Method and apparatus for aerially transporting loads, 


     5,775,640 Landing installation for landing a tethered balloon.

  • 06 Nov 2013 4:55 PM | Deleted user

    Todays patent is one of four U.S. patents issued to these co-inventors,

    two of the most famous members of the British rigid airship 


          According to an existing method, the panels of fabric are laced 

    to the hull framework by hand as tautly as possible. Sufficient tension

    cannot be obtained by this method to prevent the cover from bulging

    or flapping under the pressure of the atmosphere when in flight, and 

    it is customary therefore to apply doping medium to the cover when 

    in place to cause it to shrink and increase its tension.

          Owing to the large area of the cover involved and the difficulty 

    of access to all parts of its surface, this process of doping in situ is 

    costly and unsatisfactory. A further objection is that in the process 

    of time and under the action of weather on the fabric, the cover 

    becomes slack, and the speed of the airship is reduced owing to 

    the irregularities of surface which arise, from a slack cover. 

    The only remedy then is to re-dope the cover which adds 

    unnecessary weight to the ship and ls a costly process.

         According to the present invention, tautening of the cover in an 

    airship is obtained by mechanical means instead of through the 

    shrinking action of a dope. In consequence, it is immaterial, for the 

    purpose of tightening, whether any doping; or the like treatment for

    the fabric is applied before or after the panels are laced to the hull.”

    NOTE: The USPTO assigned 244/126 (Airship skin construction), 

    apparently because the patent eliminated the conventional doping process. 

    It neglected to cite either:

       244/125 (Airship hull construction), the devices which actually tension 

                      the skin, or

       244/130 (Aerodynamic resistance reducing), the primary reason for 

                       the invention.

    This patent has not been cited by any modern patents.

  • 05 Nov 2013 8:52 AM | Deleted user

    Todays patent is the third of Honeywell’s five aeronautical patents.

          “An important feature of the invention has reference to the 

    balloon valve and consists in the provision of a metallic valve 

    of improved construction which is not subject to the objections 

    of the usual wooden valves and in which the springs controlling 

    the closing of the valves remain permanently in position and are 

    not detached when they are packed for shipment.

          The valve is comparatively very shallow and does not permit

    the accumulation of a large quantity of water thereon as in the 

    wooden valves now in general use. The accumulation of large

    quantities of water on the valve is highly objectionable for the 

    reason that it forces itself through the valve and into the balloon

    permitting the gas to leak or escape through the valve.

    NOTE: Honeywell’s patent includes two unrelated innovations:

    •  A novel circular, metallic, low-profile valve which can be 
        permanently installed in a balloon envelope. Normally spring-loaded
        closed, its two “doors” can be be opened or held open.
    •  An improved method of suspending the balloon car and of attaching 
        ballast bags to the car.

    Unfortunately, none of  the approved claims:

    a.  indicate that the balloon might be part of an airship, 

    b. describe the method(s) by which a valve is operated, or 

    c. provide any criteria for positioning valves on the

        balloon envelope.

    This patent is cited by two modern patents:

     2,490,232 Parachute control

     4,033,527 Deflation cap for pressurized hot air airship

  • 04 Nov 2013 5:55 AM | Deleted user

    Todays patent is one of the last of Schuette’s twenty U.S. patents.

         “The steering members such as rigid fins and movable rudders, 

    as hitherto usually constructed, comprise a framework structure 

    surrounded by and enclosed in a coating or skin made of a woven

    fabric, sheet metal or the like, the framework and the skin being 

    constructed, arranged and shaped so as to set up a least possible 

    resistance to the outer air. Consequently the surrounding air 

    presses, with relation to the inner room almost all points, so that

    the skin will be greatly burdened by such pressure or load. Now 

    when it accidentally happens, that the skin becomes leaky at any 

    point, the said overpressure or underpressure may spread and 

    propagate in the interior of the steering body or member and 

    detrimentally act on parts of the skin which cannot stand the then 

    arising loads or pressures. In this way further local injuries to the 

    skin or to the framework may be brought about or even the whole 

    structure may collapse. The main object of my invention is to remedy 

    this defect and with this object in view I divide, according to the

    present invention the inner free room of the steering member into

    a number of separate compartments, by means of suitable arranged partitions.”

    Despite being the driving force behind the only company (other than 

    Zeppelin) to produce more than ten rigid airships, we have little 

    information about either Schuette or his Schutte-Lanz company 

    after World War I.

    Wikipedia describes three of Schutte-Lanz large, metal-framed

    airships; no article about the prolific inventor. 

    None of his last three U.S. patents were assigned. 

    Earlier, the American Investigation Corporation, formed by a 

    financial group led by Franklin Delano Roosevelt, acquired 

    several of his prewar patent applications, but failed in their bid 

    to build what became the USS AKRON and the USS MACON.

    NOTE: USPTO should have cited 244/126 (Airship skin construction). 

    Three of the patent’s four claims apply to the steering gear for airships

    Based on the text, “steering gear” refers to the entire empennage, the

    fixed and adjustable airfoils. 

    The fourth claim describes a partitioned airship covering,  not just the 

    fins, rudders and elevators.

    This patent is cited by a single modern patent:

    4,046,337 Hinged control surfaces for pressurized hot air airship.

  • 03 Nov 2013 10:19 AM | Deleted user

    Todays patent is one of Thaden’s five patents related to airships.

         “An object of the present invention is to provide a method of

    erection of airships, especially all-metal airships, whereby the work is

    facilitated. and greater accuracy secured, and by which method the

    entire ship is erected in situ, that is, by adding portions progressively

    to the completed part to complete the entire structure in place, thus

    obviating the erection of sub-assemblies, moving these

    sub-assemblies to place and connecting them with the completed

    part with the consequent liability of accidents, warping or springing

    of the structure and consequent inaccuracies in construction.”

    The USPTO should at least  have cited 244/125 (Airship hull construction).

    NOTE: Thaden’s invention was a novel method of assembling a rigid 

    airship.The patent text provides an extensive introduction to the 

    dominant assembly methods (British and German) which had been 

    used on nearly all earlier airships.

    N.B. Thaden’s patent requires a tall, strong assembly building. No 

    discussion of, or provisions for, installing gas cells or external

    structure (car, engines, control surfaces, etc.).

    Neither of the American all-metal airships had been started when the

    application was submitted:The Airship Development Corporation 

    employed a modified version of Thaden’s invention – apparently 

    without the jigs. It's  Metalclad was constructed as two vertically 

    assembled units, which were then rotated and joined to form the 

    ZMC-2 (TINSHIP).

    The Slate Aircraft Company method used a long raised platform which contained a huge jig, workmen stretched, corrugated and 

    trimmed each strake on the jig, then crimped and riveted each 

    succeeding strake to the airship hull as it was slowly rotated on 

    slings in front of them.

    Both the ZMC-2 and the CITY OF GLENDALE used the hull as 

    the only LTA gas holder, e.g. no separate internal gas cells. 

    You can read this patent, or link to any of the patents which cite it on

    Google/com/patents. Once again, don’t trust GOOGLE’s badly garbled 

    OCR version.

  • 02 Nov 2013 10:34 AM | Deleted user

    Todays patent is Kurose’s only U.S. patent.

    NOTE: As explained in his text, temperature inversion layers occur

    frequently. Therefore, the conventional method of controlling the 

    buoyancy of an airship on the basis of the standard atmospheric 

    conditions is unable to make the airship exercise necessary 

    ascending performance”.

    Kurose’s patent employs combinations of three methods to correct 

    for non-standard atmospheric conditions above the launch site:

       a. An on-board system of sensors and valving controls to
          monitor atmospheric temperature and pressure and to
          adjust the valves to ensure proper flow rate.

         b. Employing a sonde to establish the actual vertical 

           temperature/pressure profile shortly before launching the 

           airship, and data-linking the Temperature and Pressure 

           information to the airship's computer.

          c. Disposable ballast, jettisoned when necessary to maintain

             desired ascension rate.

    Notice, none of his claims indicate that this might be a manned

    Kurose's patent has been cited by seven U.S. airship patents:

     7055778  Apparatus and method for lighter-than-air aircraft,

     7156342  Systems for actively controlling the aerostatic lift of 

                     an airship,

     7380750  Method for lighter-than-air aircraft ,

     7487936  Buoyancy control system for an airship,

     7500637  Airship with lifting gas cell system,

     7690596  Apparatus for lighter-than-air aircraft, and

     8113463  Blimp.

  • 01 Nov 2013 8:30 AM | Deleted user

    Todays patent is one of sixteen issued to Powelson and Travell.

         “The invention comprises the provision and the combination 

    with the airship, of one or more powerful tension devices each 

    having means to indicate the relative degree of tension to which 

    it is subject from time to time. This, by measuring or comparing

    the forces acting vertically on the airship, constitutes means for 

    governing the disposition of substance on board so that the center 

    of buoyancy and center of gravity come into vertical relation while 

    the ship is moored with its axis horizontal. When these are so located

    an airship on being released from its mooring will rise on even keel; 

    but when not so located, there will be a turning movement caused by

    the vertical forces which will cause the craft to rotate in a vertical 

    plane with its longitudinal axis approaching the vertical.”

    NOTE: This patent is not cited by any modern patents, perhaps

    because the USPTO failed to read and/or to cite additional 

    classifications applicable to approved claims. The patent includes 

    nineteen claims, three provide for auxiliary airships which assist in

    launching when the airship is heavier than air. Other claims relate to

    means for trimming the ship by shifting gas or ballast (to vertically 

    align the Center of Buoyancy and the Center of Gravity), prior to 

    launching an airship which is moored to one (or two) masts, or simply

    tethered to the ground.

    Their key innovation was to incorporate a device to measure the vertical 

    force at specific location(s) on the airship hull. 

    N.B. We still didn't have any instrumentation to measure the forces 

    (axial or vertical) at the mast head when the Navy terminated its LTA 

    program in 1961.

    Among the missing classifications:

    244/93 (Stabilizing weights),

    244/96 (Airship control), and

    244/127 (Airship load attachment).

    Worth reading, but be warned, Google's OCR rendering is hopelessly


  • 31 Oct 2013 11:57 PM | Deleted user

    Todays patent is Schott’s only solo patent.

    He was a coinventor on another LTA patent assigned to 

    Goodyear, and on an “inflatable floating island” assigned 

    to the Navy.


          Heretofore, it has been the standard practice to secure the 

    control car to an airship envelope by a plurality of sets of cables. 

    One set of cables extends between the control car and the outside

    of the under portion of the envelope. A second set of cables 

    extend between catenaries in the inside of the envelope and the 

    control car, each cable being adjustable as to length by means 

    of a turnbuckle. In order to give the optimum shape to the envelope, 

    the load of the control car must be properly distributed between the 

    several sets of cables, and in the past this has necessitated very 

    considerable adjustment of individual turnbuckles keeping in

    mind the advisability of substantially uniform loading of the 

    catenary curtains. Moreover, as the envelope stretches and distorts

    in use, frequent and annoying readjustment of the turnbuckles has 

    been necessary to reduce excessively high tensions in the end 

    suspenders that resulted therefrom.

          It is the general object of the invention to avoid and overcome 

    the foregoing and other difficulties of the prior art by the provision

    of improved, relatively simple, easily applied and adjusted means

    for securing a car or other similar type of structure on the underside

    of a non-rigid airship, and characterized by ease and rapidity of

    manual adjustment and features of inherently correct longitudinal 

    load distribution in spite of envelope fabric stretch and/or a change

    of shape of the envelope.

    NOTE: Schott's patent was filed on August 6, 1959. It was issued 

    two years later; a month after Goodyear’s last client terminated its 

    airship program. 

    The invention specifies a car suspended beneath the gas filled

    envelope supported by cables from two catenary curtains and by 

    cables connected directly to the envelope. 

    It does not discuss or claim any method or means of determining

    the share of the car’s weight which is supported by any individual 


    Although not discussed, presumably adjustments are performed

    while the ship is docked, or moored under benign conditions.

    The patent is cited by three modern patents:

     3,533,578 Lighter than air craft non-rigid pressure ships 

                      and tethered glider or plane, heavier than air,

     6,290,176  Airship gondola suspension system and method 

                       of making same, and

     6,293,493  Pressure stabilized gasbag for a partially 

                       buoyant vehicle.

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