LTA PATENTS BLOG

Todays patent is Isaac’s only aeronautical patent.

Three of his 15 other U.S. patents also apply to

reelable structures.

      “My invention pertains to improvements in airfoils and hydrofoils

and is particularly concerned with the retractable versions thereof

which may be stored on a reel when not required and fed from the

reel in the rigid state when required.

      The airfoils and hydrofoils of today are of the permanent rigid

types which are permanently fixed to the vehicle. These airfoils have

several disadvantages; notably the lifting force of an airfoil depends

on the velocity at which it is forced through the air. Consequently

for take-off and landing of the aircraft, a long airfoil is desirable in

order to reduce the take-off and landing speeds. However, for flights

at high speed, short airfoils are preferable in order to reduce the

drag of the aircraft and improve its maneuverability. Hence airfoils

of today are designed as a compromise between these two conflicting

requirements. By means of the invention disclosed it is possible to

provide airfoils whose span and geometry may be varied to suit the

best requirements at any given flight condition.”

The USPTO didn’t assign:
244/75.1 (Aircraft control) or 244/96 (Airship control),
244/87 (Rudders & empennage), or
244/130 (Aerodynamic resistance reducing).

It did assign five aeronautical classifications:

244/218 (….Area) variable sustentation

244/17.11 (.Helicopter or auto-rotating wing sustained)

244123.11 (..Inflatable) Aircraft structure

244/219 (….Camber) Aircraft sustentation and

244/900 (Lightweight, winged air vehicle).

NOTE: Neither this patent, nor any of the 14 patents in which it is cited,

reference either airships or hybrid airships. Buoyancy and aerodynamic 

lift must share the load in a hybrid:

    Buoyancy – function of Temperature and Pressure - essentially

                         unrelated to velocity, roll or yaw.

    Lift - primarily a function of Shape, Velocity, and orientation.

When buoyancy or lift changes dramatically (or rapidly) variable

sustentation devices, such as these retractable airfoils, could minimize

undesired drag and lifting force excursions. (for example, maintaining 

altitude at night without having to increase speed to compensate for 

loss of buoyancy; minimizing size and drag of aerodynamic control

surfaces except when necessary.) Retractable, rather than reelable, 

airfoils probably would be simpler and lighter for a hybrid
airship application.

Todays patent is the first of five patents 

issued to Auberlin in 1927 and 1928.

All five were related to airship mooring. 

The last simply strengthened the airship’s nose.

      “To moor the airship, the wind break is turned with its apex into

the wind by the operator in the control house and the approaching

airship with its nose trimmed into the wind is moored to the sheltered

mooring mast and guy cables 14 and 14a are attached bracing and

controlling lateral movement of the airship. When the wind shifts

the mooring structure is turned accordingly,  trimming the wind break

and airship nose into the wind: The wind break protects the mooring

mast and airship from high winds and heavy gales allowing the airship

to ride safely behind and the guy cables brace against gusts varying

rapidly in direction. Turntable motor controls may be located at other

convenient points.

      My improved mooring mast eliminates the difficult maneuvering

necessary with a shed and simplifies the maneuvering with an ordinary

 mooring mast.”

The patent assumes that the wind screen (wind break) will be properly 

sized and shaped, and that that the turntable could be rapidly rotated 

to provide effective protection from turbulence or gusting winds. 

Unfortunately, it fails to mention how to minimize the time delay 

between the onset of a major change in wind velocity and an (alert) 

operator's ability to rotate the mooring assembly so that the wind 

screen, mast, and airship are properly oriented into the wind.

NOTE: This is the earliest patent I’ve found that (almost) provides 

a method of minimizing drag and overturning forces on a moored
airship and mooring mast. None of the approved claims address 

how the turntable (the pedestal) wind screen or mast are constructed, 

nor when, why, or how the entire assembly would be rotated. Only 

the third claim includes components to assist in aligning the airship 

downwind from the wind screen and mast.

          Neither the wind screen nor the mast appear to be at the 

          center of rotation. 

Fig 1 portrays the wind break as significantly taller and wider than 

the airship and fairly widely separated from the mooring mast; not 

discussed in text or claims. 

Figs 2 through 5 (the second sheet) illustrate alternative modifications 

to the airship's nose. (Not included in claims, or cited by the USPTO.)

Safety note - hopefully the operator would have some method of 

warning everyone on board the mast or airship, when he decides 

to start or stop rotating the huge assembly.

Todays patent is one of 23 U.S. patents issued to Schuette.

The umlaut resulted in the Patent Office listing his name 

either as Schutte or Schuette.

      “The object of the present invention is now to control 

the gas escape in such a manner that the escaping hydrogen 

will pass off with the least possible danger, and is, for this 

purpose rapidly and thoroughly mixed with air to such a 

degree that the ensuing mixture is beyond the dangerous ratio 

(viz 9.5 - 66.5%), so that there will be no danger of explosion 

and yet the readily accessible valves allow of a good control.

NOTE: The patent, and all six claims, apply exclusively to an 

improved gas venting system for rigid airships. Its purpose is 

to prevent the formation of an explosive mixture of hydrogen

and air inside the rigid’s envelope.

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

Most were assigned to Luftschiffbau Zeppelin or to

Goodyear-Zeppelin.

      “The cross members of a rigid airship are usually polygonal 

ring trusses comprising circumferential girders and a wire bracing. 

The wire bracing besides stiffening the ring truss in itself against 

bending stresses serves for steadying the end walls of the gas cells 

inserted between every two braced cross members, especially so in 

case of difference in pressure in two adjacent cells. Under such

circumstances which will occur for example with the leakage of 

one cell, the surplus pressure in one direction will cause an inward 

tension on the circumferential girders of the ring truss. Such tension 

stress is one of the most difficult main stresses to be carried by the 

ring truss.

      My invention does away with the possible occurrence of such 

dangerous stresses by totally omitting the wire bracing and by

making the circumferential girders so strong as to be practically 

stiff against bending stresses resulting from the ship's load. The 

end wall of a gas cell in case of leakage in the adjacent cell will 

bulge through the middle opening of the ring structure. For the 

purpose of giving support to this wall, if thought necessary, a 

resilient or elastic network may be provided which transmits part 

of the stress to the circumferential truss.But as the net work will 

be chosen so as to allow a considerable pitch of camber with regard 

to the ring plane the stresses transmitted will be practically negligible

when compared with the stresses resulting from the former wire 

bracing where the pitch of camber was very low and also an 

advance tension had to be given to the wires.”

NOTE: All three approved claims specify the use of a network within 

each strong ring truss, thereby limiting the movement of a gas cell

in the event of leakage in a neighboring gas cell.

Todays patent is the third of Hagenlocher’s four airship patents

issued in the U.S.

     The avowed purpose of the patent is to eliminate the requirement

for mobile or stick-masts at secondary landing sites. Although discussed 

in the patent, none of the approved claims indicate that this supporting 

frame might be removable. 

     The patent doesn’t discuss, and no claim indicates, how far the frame 

might be from the longitudinal center of the airship. (Assuming the ship 

is anchored so that it rotates about this frame, the net “weathervane” 

rotational force decreases the closer the frame is to the body midpoint. 

No turning/restraining force other than the wind is mentioned.

     The remaining 22 of the 23 approved claims descend directly, or 

secondarily, from the first claim:

“An airship construction comprising a supporting frame including 

sets of cross-ribs and longitudinal beams interconnecting said sets 

of cross-ribs at respective nodes, each of said sets of cross-ribs 

defining a cross-plane perpendicularly to a longitudinal axis of said 

airship, a gondola secured to said supporting frame, a bi-pod landing 

gear including at least two landing wheels and an anchoring device, 

a wheel mounting for each of said landing wheels, each wheel 

mounting comprising a triangular truss frame, both truss frames 

being positioned in one cross-plane of said cross-planes, said one 

cross-plane being positioned forward of an aerodynamic center of 

wind pressure of said airship construction, each truss frame 

comprising a portion of said airship construction forming a first 

triangle side and two connecting elements forming second and 

third triangle sides interconnected to form an outer triangle 

corner opposite said one triangle side, each of said at least two 

wheels being connected to a respective outer triangle corner, 

said two connecter elements being pivoted to ends of said first 

triangle side so that a triangle plane of each triangular truss 

frame coincides with said one cross-plane, and an anchor 

mounting securing said anchoring device to a floor of said 

gondola in an area of said one cross-plane.

Don’t blame the inventor, this is a typical "Patent-speak" claim sentence.

Claims 2 through 8, 10, and 21 through 23 expand (or limit) Claim 1.

Claim 9 modifies Claim 8 (the wheels may castor).

Claims 11, 12, and 16 modify Claim 10 (which introduces the ground 

hold-down mechanism).

In turn they are modified as follows:

   Claim 11 by Claims 14 and 15,

   Claim 12 by Claim 13, and

   Claim 16 by Claims 18, 20 and 17 (which is modified by Claim 19).

This patent is referenced by three subsequent U.S. patents:

6,286,783 (Kuenkler) Aircraft with a fuselage substantially 

                                   designed as an aerodynamic lifting body, 

6,311,925 (Rist)  Airship and method for transporting cargo,

7,500,638 (Colvin) Heavy lift airship.

Todays patent is the only U.S. patent issued to Willows that I’ve found.

Willows (Royal Aircraft Club Airship Pilot #1) was England’s 

pioneer airship builder and pilot. 

(See www.raescardiff.innerdown.co.uk/willows.htm), and

BATTLEBAGS: BRITISH AIRSHIPS OF THE 

                             FIRST WORLD WAR.

Willows built five airships before joining Airships Ltd as 

Chief Engineer in 1914:

Willows No.1 (72 feet long, 18 foot diameter, 12,000 cubic foot 

      envelope) powered by a single 7 HP Peugeot engine driving 

      multiple propellers. First Flight on 5 September 1904.

Willows No.2 (86 feet, 21,000 cubic foot envelope with a single 

      ballonet, powered by a single 30 HP engine) first flight on 

      26 November 1909. It included his swiveling propellers, 

      described in British patent (BP 14,434).

      No.2’s car was then attached to a larger envelope (32,000 cubic 

      foot, with fore and aft ballonets) and renamed CITY OF CARDIFF. 

Willows No. 3, first flight on 29 October 1910. A week later Willows 

      and his mechanic Frank Gooden, made the first channel crossing

      from England to France, with an emergency landing at Corbehem,

       France. The ship was repaired at the Clement-Bayard Works, 

       finally arriving in Paris on 7 January 1911.

Willows No. 4 (110 foot, 24,000 cubic foot envelope) flight testing in 

      June 1912; was demonstrated to a representative of the RFC (Royal 

      Flying Corps). The Admiralty purchased No. 4, and its shed, on 

      18 July 1912, and renamed it the HMA No.2.

Willows No. 5 (50,000 cubic foot envelope, single 60 HP engine)

       completed and flown from his works and Flight School at 

       Herndon in 1914.

      “According to the invention I mount the spindles to which 

the propellers are secured in such manner as to be capable of a 

movement of partial rotation in the plane of their axes and I carry 

each of the propeller spindles upon a tubular member or frame 

part through which a live axle passes by which the drive is 

communicated to the propeller spindles, a set of bevel or other gear 

wheels being advantageously provided to communicate movement 

from the end of the live axles to the respective propeller spindles, 

while similarly the tubular member or frame part is so provided or 

cut away as to permit of the drive being communicated from the 

engine to the live axle referred to in such manner that the partial 

movement of rotation is allowed to the tubular part without 

interference with the driving gear."

NOTE: None of the patent’s four claims even mention an engine 

(or engines). All of the Willows airships, and the SS-2, had only one 

engine.

A Russian Wing-In-Ground-Effect design is the only modern 

patent which cites this tilting propeller patent. 

Todays patent is the second of three patents issued to

Ralph Hazlett Upson in the spring of 1914.

Todays patent is the second of McKechnie’s airship patents 

issued in the U.S.

     “This invention relates to cars for use on lighter-than-air 

craft such as airships or dirigible balloons (hereinafter termed 

airships).”     

 “According to another feature of the present invention and for 

the purpose of resisting shock on landing a pneumatic "bumping" 

or buffer bag or bags of any usual construction may be placed on 

the underside of the car framework and held in position by being 

inclosed within, or surrounded by a watertight fabric covering, thus

providing a water tight space or compartment (or spaces or 

compartments) of considerable area around the bag or bags. By these 

means a sufficient displacement is obtained when landing on water 

to support the whole car, while, at the same time, a buffer bag of 

smaller size than would otherwise be required can be employed. The

weight of the buffer bag is thus reduced to a minimum while at the 

same time a bag of sufficient strength to resist the increased internal 

air pressure encountered at high altitudes can be used.”

NOTE: The patent only addresses two elements of McKechnie's  

streamlined airship car: A large area window array at the front end 

of the car for the navigator/bombardier and helmsman positions; and

The patent doesn’t discuss indicate when or how the bumper device
is inflated. Nor does it describe the rest of the car, the airship, or how 

and where they are connected.

Although all four claims include the buffer bag, the USPTO neglected 

to assign: 244/30 (Airship), 244/100A (Inflatable landing gear), or  

244/100R (Landing gear).

Todays patent is one of Lehmann’s three airship patents.

Lehmann was co-inventor on three other patents. All six were 

assigned to Luftschiffbau Zeppelin.

     “The main object of my invention is an advantageous 

distribution of the different gas cells with the gas they contain 

over the length of the ship, especially with ships in which two 

kinds of buoyant gases are used in combination with a fuel 

gas for feeding the motors.

      Of course, it is best to use only a non-inflammable gas, 

such as helium, as lifting gas. But it is expensive and 

comparatively heavy, so that in many cases it is advisable to 

make use of the cheaper and lighter hydrogen also. Consequently, 

in such cases three kinds of gas have to be distributed over the 

inner space of the ship's hull and gas cells of adequate material 

have to be provided therefor.

      According to my invention the different gas containers and 

the gases with which they are inflated are so distributed 

longitudinally of the airship that there are always at least two 

neighbouring cells inflated with fuel gas. This fuel gas is always 

heavier than the lifting gases. It is therefore preferred to have the 

fuel gas containers in the lower portions of the compartments.”

NOTE: Lehmann claimed a complex array of gas cells, containing 

Helium, Hydrogen, and Fuel Gas. Lehmann did not mention 

BLAUGAS, just that his fuel gas was heavier than either of  his 

“lifting gases”, possibly heavier than air.

The patent doesn’t discuss or claim any process for purging and refilling 

the various cells after a flight, or of transferring gases between similar 

gas cells to maintain the ship in trim.

USPTO failed to cite 244/61 (Power plant using airship gas as fuel).

The patent doesn't even mention a liquid fuel.

Todays patent is Munk’s second U.S. patent which incorporates an

Air Cushion Landing System in a (primarily) LTA vehicle.

This patent, originally assigned to Advanced Technologies Group, 

was reassigned to Hybrid Air Vehicles LTD, and is currently 

assigned to Skycat Group LTD. 

(His P/N 6,880,783 was originally assigned to Hybrid Air Vehicles.)

The patent has been cited by eleven subsequent U.S. patents!

NOTE: We almost got a chance to find out if his approach would be 

worth the complexity involved, under ideal operating conditions.

A modest sized variant, the LEMV, was permitted to make a single 

test flight, (Launching and recovering from a runway at NAS Lakehurst)

before the U.S. Army terminated the developmental LEMV Program.

I have no idea how much power was available to supply air to

the LEMV's huge landing pads, or whether they had any installed

instrumentation to measure the remarkably erratic pressure and flow 

fields during launch and recovery (or taxiing) operations.

Hopefully, instead of disposing of the vehicle as scrap, DoD will permit
the Skycat Group (or someone) to acquire the prototype and continue
research on this unique hybrid vehicle.