US3513933A - Multiskirt ground effect machine - Google Patents

Multiskirt ground effect machine Download PDF

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Publication number
US3513933A
US3513933A US747217A US3513933DA US3513933A US 3513933 A US3513933 A US 3513933A US 747217 A US747217 A US 747217A US 3513933D A US3513933D A US 3513933DA US 3513933 A US3513933 A US 3513933A
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United States
Prior art keywords
skirt
skirts
platform
cushion
vehicle
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Expired - Lifetime
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US747217A
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English (en)
Inventor
Marc Henrl Jean Faure
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Societe dEtudes et de Developpement des Aeroglisseurs Marins SEDAM SA
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Societe dEtudes et de Developpement des Aeroglisseurs Marins SEDAM SA
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60V—AIR-CUSHION VEHICLES
    • B60V1/00—Air-cushion
    • B60V1/16—Flexible skirts

Definitions

  • An air cushion vehicle comprising a movable skirtcarrier structure highly permeable to cushion supply fluid and connected to a rigid platform through a resilient suspension system which is immersed in the cushion fluid and designed for taking only a minor fraction (say, 5 to of the load, the major part being transmitted directly by cushion pressure to said platform owing to the high permeability of said skirt-carrier structure.
  • the present invention relates more particularly to a ground-effect machine of this kind, comprising at least one inner skirt bounding a central cushion and at least one outer skirt bounding a peripheral cushion, the latter being conveniently subdivided into a number of fragmentary cushions by partitions extending between the inner skirt and the outer skirt and which may be themselves stability skirts engaging more or less tangentially said inner and outer skirts.
  • One of the objects of the present invention is to combat this detrimental phenomenon by the removal or at least the substantial reduction of this tore-shaped vortex.
  • Another object of the present invention is to decrease the apparent stiffness and the proper frequency of the vehicle in order to improve its dynamic stability characteristics, on account of the achievement of a negative variation ratio of cushion volume and pressure.
  • the present invention also allows decreasing the vertical accelerations to which the structure of the vehicle would be subjected upon displacements over uneven ground or waves.
  • the ground effect machine comprises a movable skirt-carrier structure which is highly permeable to the cushion supply fluid and which is connected through a resilient suspension to a rigid part of the machine such as a platform, this resilient suspension, immersed in the cushion fluid, being designed for transmitting only a minor fraction of the load, most of which is transmitted directed by cushion pressure to said rigid part owing to the high permeability of said skirt-carrier structure.
  • FIG. 1 is a schematic vertical section of a vehicle according to the present invention, taken along line I-I of FIG. 2;
  • FIG. 2 is a plan view of it from beneath
  • FIG. 3 is a similar view showing a detail of the supply system
  • FIG. 4 is a larger scale fragmentary section taken along line IVIV of FIG. 3;
  • FIG. 5 is a very schematic plan view of an embodiment with multilobed skirts.
  • the vehicle illustrated on FIGS. 1 to 4 comprises two frustocom'cal concentric skirts 1, 2 of flexible material having a bottom skirt diameter ratio in the range of 0.6 to 0.8, the taper of the outer skirt 1 being in excess of 10 to 20 compared with that of the inner skirt 2.
  • a minimum of three stability skirts 3 are required and there are six of them in the illustrated embodiment.
  • skirts 1-2-3 are hooked at their top to a light structure 4 which may be tubular.
  • This assembly of skirts and structure has for instance a mass comprised between 4 and 8% of the total mass of the vehicle.
  • a flexible inverted conical side-wall connects the outer circle 6 of the skirt-carrier structure 4 to the underface 7 of the vehicle structure properly speaking or platform 8, along a circle 9 which has a diameter 0.8 to 0.9 time that of circle 6 at the top of the outer skirts 1.
  • the skirt-carrier structure 4 is also connected to platform 8 through a resilient system 10 'which acts under compression and takes between 5 and 15% of the weight of the vehicle.
  • the resiliency is determined so that the ratio between the daylight clearance h of the inner skirt 2 with respect to the ground and the height of the passage 11 between circle 12 which carries the inner skirt 2 and the underface 7 of platform 8, remains substantially constant irrespective of the load of the vehicle.
  • the resilient suspension 10 between the skirt-carrier structure 4 and the platform 8 may be supplemented by hydraulic, pneumatic or friction damping devices, as described in US. specification No. 3,339,657.
  • a distribution grate 16 is fitted under the central subplenum 17 so that the flow is shared in conformity with a preselected law between the central compartment 14 and the peripheral compartments 18 bounded by the outer skirt 1, the inner skirt 2 and the stability skirts 3.
  • This grate 16 is conveniently fast with the skirt-carrier structure 4 and its displacement thereby gives rise to vibration damping by friction of air through its mesh.
  • Grate 16 has been illustrated as extending only above the central plenum chamber 14. It may however be extended so as to overlap also some or all of the peripheral 3 plenum chambers 18, with the exclusion of the stability skirts 3.
  • a member 21 protruding from platform underface 7 extends around inner skirt 2 (except on the portions registering with the stability skirts 3 and their supply duct 15), enables the designer to define easily the desired law of variation of the air passage area for the peripheral plenum chambers 18 as a function of the displacement of the skirt-carrier structure 4.
  • This law will be such that the sum of the lower and upper passage areas (cf. arrows f1 and f2) between the central plenum chamber and the peripheral ones will be equal to 1 to 3 times the passage area (cf. arrow f3) between the latter and the ambient medium.
  • This last feature constitutes one of the basic characteristics of the present invention. It derives from the fact that the skirt-carrier structure 4 and the distribution grate 16 are highly permeable to the cushion supply fluid discharged by the fan(s) 13, so that the resilient suspension system 10 interposed between the movable structure 4 and the rigid platform 8 is immersed in cushion fluid, and cushion pressure, disregarding small losses of head, applies directly to the underface 7 of platform 8.
  • the situation would of course have been quite different, had the skirtcarrier structure 4 been a fluidtight closure for the cushions, subjected to their pressure and transmitting the resultant effort to platform 8 through the resilient suspension system 10 which would then be exposed to open air, as in the case of the devices described in the last mentioned specification, wherein the suspension system takes practically the whole load.
  • suspension 10 of the device of the invention only takes, as stated, a minor fraction of the load about 5 to 15%.
  • the slant of the vehicle platform 8 is from 2 to 5 times larger than that of the bottom plane of the skirts. Therefore the attitude changes of the vehicle on uneven ground will be smaller than the changes in slope of the ground.
  • the case has been considered of a generally disc-shaped vehicle with skirts of circular planform.
  • the invention is applicable without difliculty.
  • FIG. 5 shows the skirt-carrier structure 4" of an elongated vehicle with multilobed skirts having flexible planar sheets 20 separating the various lobes. If the number of sheets 20 is important, it is possible to do without stability skirts 3 or to reduce their number, the partitioning between the inner skirt 2 and the outer skirt 1 being then sufficient to ensure pitch and roll stability of the vehicle.
  • a multicushion ground effect machine having a platform or like rigid portion designed to hover above a supporting surface with the interposition of pressure fluid cushions, comprising a movable structure highly permeable to cushion fluid extending under said platform in spaced relationship and defining therewith a supply manifold, a plurality of cushion containing skirts depending from said movable structure and carried thereby, the space bounded by said skirts communicating directly with said manifold through said highly permeable structure, cushion pressure fluid generating means discharging into said manifold, and a resilient suspension system extending between said platform and said skirtcarrier structure, inside said supply manifold and immersed in pressure fluid, said resilient suspension system being designed for taking only a minor fractionof the weight of the machine and transmitting the same to said platform while the major part of said weight is transmitted directly to said platform by cushion pressure exerted thereon through said highly p ermeable skirtcarrier structure.
  • said cushion containing skirts comprise at least one inner skirt adpated for containing a central cushion, at least one outer skirt adapted for containing a peripheral cushion, and partition means extending between said inner and outer skirts for subdividing said peripheral cushion into a plurality of fragmentary cushions.
  • said partition means comprises at least one stability skirt engaging substantially tangentially said inner and outer skirts.
  • Machine as claimed in claim 2 further comprising a fluid distribution grate extending across the communication between said supply manifold and the space bounded by said inner skirt.
  • Machine as claimed in claim 1 further comprising spacer means interposed between said platform and said skirt-carrier structure for limiting the stroke of said skirtcarrier structure towards said platform, whereby said supply manifold has a width which cannot decrease beyond a minimum value.
  • said skirtcarrier structure comprises a light-weight frame made of tubular sections.
  • Machine as claimed in claim 1 further comprising shaped protrusions extending from said platform and cooperating with said movable skirt-carrier structure, to define therewith variable-area passages in said supply manifold, as said skirt carrier structure moves relatively to said platform.
  • Machine as claimed in claim 1 wherein said resilient suspension system is designed for taking from about 5% to about 15% of the total weight of the machine.

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  • Engineering & Computer Science (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Vehicle Body Suspensions (AREA)
  • Combined Devices Of Dampers And Springs (AREA)
US747217A 1967-07-27 1968-07-24 Multiskirt ground effect machine Expired - Lifetime US3513933A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR115933A FR1541013A (fr) 1967-07-27 1967-07-27 Machine à effet de sol

Publications (1)

Publication Number Publication Date
US3513933A true US3513933A (en) 1970-05-26

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Application Number Title Priority Date Filing Date
US747217A Expired - Lifetime US3513933A (en) 1967-07-27 1968-07-24 Multiskirt ground effect machine

Country Status (3)

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US (1) US3513933A (enrdf_load_stackoverflow)
FR (1) FR1541013A (enrdf_load_stackoverflow)
GB (1) GB1227882A (enrdf_load_stackoverflow)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3643757A (en) * 1968-05-09 1972-02-22 Aeroglisseurs Marins Flexible skirts for surface-effect machines
US3791478A (en) * 1971-03-31 1974-02-12 Etat Fr Defense Nat Delagation Apparatus for confinement of an air cushion of a vehicle riding on same
US3951227A (en) * 1974-01-04 1976-04-20 Societe D'etudes Et De Developpement Des Aeroglisseurs Marins, Terrestres Et Amphibies S.E.D.A.M. Ground-effect vehicles
US4042060A (en) * 1974-08-05 1977-08-16 Bertin & Cie Air-lift vehicles
US4060147A (en) * 1975-02-18 1977-11-29 Bertin & Cie Vehicles riding on air cushions
US4077589A (en) * 1976-11-02 1978-03-07 Belolipetsky Alexei Yakovlevic Ground-effect landing gear for aircraft
US4096921A (en) * 1977-06-10 1978-06-27 Paul Francois Guienne Vehicle supported by an air cushion
US4396082A (en) * 1979-09-18 1983-08-02 Societe D'etudes Et De Developpement Des Aeroglisseurs Marins Terrestres & Amphibies (S.E.D.A.M.) Air cushion vehicles
US7296526B1 (en) 2006-08-31 2007-11-20 Textron Inc. Dual stability seal skirt system for air cushion vehicle

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2164773C3 (de) * 1970-12-31 1975-07-17 Societe D'etudes Et De Developpement Des Aeroglisseurs Marins Terrestres Et Amphibies S.E.D.A.M., Paris Luftkissenfahrzeug mit von Schürzen begrenzten Mittel- und Randkissen
FR2123106B1 (enrdf_load_stackoverflow) * 1970-12-31 1973-12-28 Sedam

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3185240A (en) * 1962-01-25 1965-05-25 Vickers Armstrongs Ltd Air-cushion borne vehicles
US3266757A (en) * 1963-12-06 1966-08-16 Bertin & Cie Devices for landing loads
US3414076A (en) * 1965-04-30 1968-12-03 Bertin & Cie Gas-cushion devices intended to support or guide a movable load
US3438457A (en) * 1966-02-01 1969-04-15 Bertin & Cie Multi-cushion system for a surface effect vehicle

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3185240A (en) * 1962-01-25 1965-05-25 Vickers Armstrongs Ltd Air-cushion borne vehicles
US3266757A (en) * 1963-12-06 1966-08-16 Bertin & Cie Devices for landing loads
US3414076A (en) * 1965-04-30 1968-12-03 Bertin & Cie Gas-cushion devices intended to support or guide a movable load
US3438457A (en) * 1966-02-01 1969-04-15 Bertin & Cie Multi-cushion system for a surface effect vehicle

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3643757A (en) * 1968-05-09 1972-02-22 Aeroglisseurs Marins Flexible skirts for surface-effect machines
US3791478A (en) * 1971-03-31 1974-02-12 Etat Fr Defense Nat Delagation Apparatus for confinement of an air cushion of a vehicle riding on same
US3951227A (en) * 1974-01-04 1976-04-20 Societe D'etudes Et De Developpement Des Aeroglisseurs Marins, Terrestres Et Amphibies S.E.D.A.M. Ground-effect vehicles
US4042060A (en) * 1974-08-05 1977-08-16 Bertin & Cie Air-lift vehicles
US4060147A (en) * 1975-02-18 1977-11-29 Bertin & Cie Vehicles riding on air cushions
US4077589A (en) * 1976-11-02 1978-03-07 Belolipetsky Alexei Yakovlevic Ground-effect landing gear for aircraft
US4096921A (en) * 1977-06-10 1978-06-27 Paul Francois Guienne Vehicle supported by an air cushion
US4396082A (en) * 1979-09-18 1983-08-02 Societe D'etudes Et De Developpement Des Aeroglisseurs Marins Terrestres & Amphibies (S.E.D.A.M.) Air cushion vehicles
US7296526B1 (en) 2006-08-31 2007-11-20 Textron Inc. Dual stability seal skirt system for air cushion vehicle
WO2008028077A1 (en) 2006-08-31 2008-03-06 Textron Inc. Dual stability seal skirt system for air cushion vehicle

Also Published As

Publication number Publication date
FR1541013A (fr) 1968-10-04
GB1227882A (enrdf_load_stackoverflow) 1971-04-07

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