US3662689A - High speed train utilizing hard superconductor - Google Patents

High speed train utilizing hard superconductor Download PDF

Info

Publication number
US3662689A
US3662689A US53773A US3662689DA US3662689A US 3662689 A US3662689 A US 3662689A US 53773 A US53773 A US 53773A US 3662689D A US3662689D A US 3662689DA US 3662689 A US3662689 A US 3662689A
Authority
US
United States
Prior art keywords
train
magnetic field
superconducting
ladder
hard
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.)
Expired - Lifetime
Application number
US53773A
Other languages
English (en)
Inventor
Ushio Kawabe
Hiroshi Kimura
Toshio Doi
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.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Application granted granted Critical
Publication of US3662689A publication Critical patent/US3662689A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L13/00—Electric propulsion for monorail vehicles, suspension vehicles or rack railways; Magnetic suspension or levitation for vehicles
    • B60L13/10—Combination of electric propulsion and magnetic suspension or levitation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L13/00—Electric propulsion for monorail vehicles, suspension vehicles or rack railways; Magnetic suspension or levitation for vehicles
    • B60L13/04—Magnetic suspension or levitation for vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60V—AIR-CUSHION VEHICLES
    • B60V3/00—Land vehicles, waterborne vessels, or aircraft, adapted or modified to travel on air cushions
    • B60V3/02—Land vehicles, e.g. road vehicles
    • B60V3/04—Land vehicles, e.g. road vehicles co-operating with rails or other guiding means, e.g. with air cushion between rail and vehicle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2200/00—Type of vehicles
    • B60L2200/26—Rail vehicles

Definitions

  • ABSTRACT Superconducting high speed train system comprising a rail including at least one elongated hard superconducting member disposed horizontally along the running direction of the train and having a hollow or gap portion extending in the elongated direction, and a train body including a superconducting magnet for generating a magnetic field perpendicular to the hard superconducting member, thereby floating the body from the rail by the magnetic force acting between the superconducting magnet and the hard superconducting member.
  • the wheels of a train are driven by a motor and the train moves due to the friction between the wheels and the rails.
  • vibrations of the body become so large as to cause the possibility of running off the rails and also problems of skid occurs.
  • the weight of a train is so large, there have been no appropriate means to float a train from the rail and thus it has been impossible to realize a train which can run at a speed above 300 Km/hr.
  • an object of the invention is to provide a novel hovercraft high speed train.
  • an object of the invention is to provide a high speed train utilizing the magnetic floating effect to float the train above the ground and drive it in a floated state to provide a speed higher than 300 Km/hr.
  • an inhomogeneous hard superconductor is used according to this invention to provide a sufficiently large floating force by the magnetic shielding effect.
  • FIGS. 1 and 2 are magnetization curves of a soft and a hard superconducting material, respectively.
  • FIG. 3 illustrates the principle of magnetic floating according to the invention.
  • FIG. 4 illustrates the magnetic shielding effect
  • FIG. 5 is a schematic diagram for illustrating the driving principle according to the invention.
  • FIG. 6 is a schematic diagram of a driving system according to the invention.
  • FIG. 7 is a schematic partial cross section of a rail according to the invention.
  • FIGS. 8 and 9 are schematic cross-sectional views of embodiments of the invention.
  • FIG. 1 shows a magnetization curve with the abscissa representing external magnetic field H, and the ordinate representing magnetization (-M).
  • H the abscissa representing external magnetic field
  • -M magnetization
  • the present invention is based on the use of the magnetic shielding effect of an inhomogeneous hard superconductor which can provide a floating force several thousand times greater than that in the case of utilizing the Meissner effect.
  • Nb-Zr-Ti Nb Sn, V -,Ga, Nb (Al Ge etc. each of which shows a magnetization characteristic as shown in FIG. 2.
  • M the intensity of the magnetization of a hard superconductor placed in the magnetic field
  • H the rate of increase of the magnetization (-M) gradually decreases with a certain point forming a peak and then the magnetization begins to decrease.
  • the superconducting state is broken for the first time.
  • the region of H, 11, is called the Meissner region similar to the preceding case
  • the region of l-l H, H is called the magnetic shielding region.
  • a spatial region of less magnetic field i.e. magnetic field diluted space
  • a magnetic field penetrates into a hard superconductor to such an extent where the pinning force due to dislocations and/or precipitation defects in the hard superconductor is balanced by the Lorentz's force that the magnetic flux due to an external field tends to penetrate into the hard superconductor.
  • an induction current flows in a surface region, to the inner boundary of which said magnetic flux could penetrate.
  • the magnetic flux due to the external field is prevented from penetrating into the hard superconductor further to form a region of extremely less magnetic flux in the hard superconductor.
  • the depth of penetration of the magnetic flux into the hard superconductor depends on the intensity of the external field and is about 10 times larger than that of the surface layer in which current flows by the meissner effect.
  • the magnetic shielding effect produces a region of less magnetic field in a hard superconductor, while the Meissner effect produces a region of no magnetic field in a superconductor.
  • the magnetic characteristics of the two are quite different, but in both cases a superconductor placed in a magnetic field having a uniform gradient receives a force in the direction along which the magnetic field decreases.
  • discs 1 and 2 formed of inhomogeneous hard superconductor are disposed parallel to each-other by supporting members 3 and 4, as is shown in FIG. 3.
  • a superconducting solenoid 5 is disposed in such a position to produce a magnetic field H substantially perpendicular to the disc surfaces.
  • the former property of a hard superconductor i.e., the magnetic shielding property
  • the magnetic shielding property is utilized in this invention.
  • the magnetic field in the gap of .the discs is about 2 kilogauss showing that the magnetic field is very weak between the discs.
  • the structure 1 to 4 is floated upward to the direction along which the magnetic flux decreases.
  • the structure is stable in the radial direction.
  • the gravitational direction it is stable at a position where the floating force is balanced with the gravitational force. This is completely contrary to the case of a ferro-magnetic body.
  • a force acts on the superconducting solenoid 5 to move it downward.
  • the high speed train according to the present invention is floated by the above-described principle with the maximum floating force expressed by (l'y)H/8 1r (dyne/cm (H,., H H
  • 'y is the magnetic shielding factor and in FIG. 4 'y H'lH.
  • H is the upper critical magnetic field as shown in FIG. 2 and has a value about 100 times larger than the usual lower critical magnetic field of a soft superconductor.
  • the factor 'y can be brought to a value very near to zero by the geometrical configuration and the material.
  • an apparatus-utilizing the magnetic shielding characteristic can afford a floating force about several thousand times larger than that of the conventional apparatus utilizing the Meissner effect.
  • FIG. 5 illustrates the principle of the driving system, in which reference numeral 5 indicates a saddle-shaped solenoid, 6 a ladder-shaped conductor, and 7 a DC source.
  • the saddle-shaped solenoid 5' works with the superconducting coil 5 of FIG. 3 for generating a magnetic field H in the direction indicated by an arrow H in the figure.
  • a current I is allowed to flow by the DC source 7 in the direction indicated by an arrow I.
  • a force acts on the saddle-shaped solenoid in the direction indicated by an arrow F.
  • the driving acceleration dv/dt of the saddle-shaped solenoid 5 is expressed by:
  • the hovercraft superconducting train is theoretically driven with an acceleration of l5-g (cm/sec an acceleration fifteen times larger than gravitational acceleration.
  • the effective cross section of the magnetic field of the saddle-shaped solenoid is arranged to be 1(m) X 5(m) and the magnetic shielding factor 7 0.2, the maximum floatable weight is 5,000 (ton).
  • curved plates 10, 11, 12 and 13 formed of a hard superconducting material such as an Nb Sn sintered body are placed to form opposing pairs by 10 and 12, and 11 and 13, and are supported by supporting structure 14 to 17 at the four corners.
  • the use of curved plates facilitates the effective use of the applied magnetic field in such a manner that the external field is wholly applied perpendicular to these curved plates.
  • the portion 18 surrounded by these curved hard superconductor plates forms a refrigerant passage. For example, liquid helium or helium gas at a very low temperature is allowed to flow through this passage to keep the plates 10 to 13 in the superconducting state.
  • These structures are contained in a rail 19 formed of concrete. In the upper surface of said rail 19, ladder-shaped conducting circuits 6 are formed along the running direction of the train.
  • FIG. 7 is a partially cross-sectional schematic perspective view of a rail for a high speed train in which similar parts as those of FIG. 8 are indicated by similar reference numerals.
  • the body of a high speed train is, for example, divided into the upper and the lower part.
  • seats 20 are disposed in double-layered chambers and double-glassed windows 21A to 21D are formed in the wall of both chamber.
  • the lower part has a reversed U shaped corss section and rides on the rail 19.
  • a saddle shaped coil 5 such as shown in FIG. 5 is disposed in the lower part in a position facing the ladder-shaped conducting circuit of the rail. Further in positions facing against the hard superconducting plates 11 and 13, control solenoids for guiding the rail 22 and 23 are respectively provided.
  • safety tires are provided on the bottom portion of the body.
  • the body of the train receives a force and begins to move in the direction of the front side of the figure.
  • the intensity of the magnetic field is decreased, the speed of the train decreases and the floating force decreases. If the magnetic field is further decreased to zero, the train runs on safety tires 24 and 25 for some distance and halts.
  • a current allowed to flow through the solenoids 22 and 23 produces magnetic fluxes 41 and The solenoids 22 and 23 receive a force by the interaction with the lesser magnetic field region 18 to a direction along which the magnetic flux decreases. This interaction prevents rolling of the body.
  • an extremely large floating force can be provided by the use of the magnetic shielding characteristic of a hard superconductor and a train can be driven at a very high speed.
  • F IG. 9 shows another embodiment of the invention in which the body of a train is hung down from concrete rails.
  • discs to 32 and 33 to 35 formed of curved hard superconductors are supported by supporting members 36 and 37 to be mutually parallel, respectively. These discs 30 to 35 are immersed in liquid helium and held in the superconducting state.
  • ladder-shaped circuits 61 and 62 are formed on the upper surface of said rails 41 and 42.
  • the body of the train is separated into a double structured passenger car portion in which seats 20A to 20F are disposed and a portion containing field coils 51 and 52. These two portions are connected by a connecting shaft 38. Liquid helium is also contained in the upper portion to keep the field coils 51 and 52 in the superconducting state. There are also provided safety tires 39 and 40.
  • a train is floated by the interaction of the magnetic field established by superconducting field coils 51 and 52 and the weak magnetic field in the gap of the curved discs 30, 31, 32 and 33, 34, 35 and is further driven by the interaction of the field by the field coils 51 and 52 and the currents flowing through the ladder-shaped circuits 61 and 62 to run above the rails at a very high speed.
  • This embodiment provides an advantage in that the stability of the rail guiding of a train is very large.
  • the Lorentzs force acting on the magnetic field and the current in the ladder-shaped conductor is utilized to drive a train, but other means such as a linear motor or jet propelling can also be employed in place of the Lorentzs force.
  • a large floating force needed for floating a train can be easily provided with less power consumption by the utilization of the magnetic shielding effect of a hard superconductor according to the invention.
  • the magnetic field established by the field coil for floating the train can also be utilized for propelling a train to reduce the manufacturing cost.
  • the control of starting, halting, or varying the speed of a train can be extremely easily done by controlling the magnitude and the direction of the current flowing through the ladder-shaped circuit.
  • a superconducting high speed train system comprising:
  • train rail means including at least a pair of inhomogeneous hard superconducting plates disposed along the running direction of a train, vertically facing to one another, and means for cooling said superconducting plates to keep them in the superconducting state;
  • a body of a train accommodating thereon a superconducting field coil, means for operating said coil to generate a magnetic field perpendicular to the surface of said hard superconductor plates and means for cooling said coil to keep the same in the superconducting state, whereby floating the train body by the interaction of the magnetic field established by said superconducting coil means and the weak magnetic field formed in the gap of said pair of hard superconductor plates; and means for driving said train body in the floated state.
  • a superconducting high speed train system comprising:
  • train rail means including at least a pair of inhomogeneous hard superconductor plates disposed in vertically facing relation to each other along the running direction of a train, means for cooling said superconductor plates to keep them in the superconducting state, and laddershaped circuit means for allowing a current to fiow perpendicularly to the running direction of the train;
  • a body of a train including superconducting coil means for generating a magnetic field perpendicular to the surfaces of said hard superconductor plates and said laddershaped circuit, and means for cooling said coil means to keep the same in the superconducting state, whereby floating the train by the interaction of the magnetic field generated by said superconducting coil means and the weak magnetic field formed in the gap of said pair of hard superconductor plates; and means for controlling the current flowing through the ladder-shaped circuit means whereby propelling the train by the force caused by the magnetic field generated by said superconducting coil means and the current flowing through said laddershaped circuit means.
  • a superconducting high speed train system in which said ladder-shaped circuit means includes a number of ladder-shaped unit circuits, each having an appropriate length and said control means includes switch means provided to the respective unit circuits for controlling the magnitude and the direction of the flow of current, thereby controlling the starting, braking or speed of the train.
  • a superconducting high speed train system comprising:
  • train rail means including two pairs of inhomogeneous hard superconductor plates disposed in horizontally and vertically facing relation to one another along the running direction of a train, means for cooling said superconductor plates to keep them in the superconducting state, and ladder-shaped circuit means for allowing current to flow perpendicularly to the running direction of the train;
  • first superconducting coil means for generating a magnetic field perpendicularly to the surfaces of a pair of said hard superconductor plates facing vertically and said ladder-shaped circuit means
  • second superconducting coil means for generating a magnetic field perpendicularly to the surface of another pair of said hard superconductor plates facing horizontally, whereby the train is floated by the interaction of the magnetic field generated by said first superconducting coil and the weak magnetic field in the gap of said pair of hard superconductor plates facing vertically, and controlled the position thereof by the interaction of the magnetic field generated by said second superconducting coil and the weak magnetic field formed in the gap of said another pair of hard superconductor plates facing horizontally; and means for controlling the current flowing through said laddershaped circuit means whereby the train is propelled by the force caused by the magnetic field generated by said first superconducting coil means and the current flowing through said ladder-shaped circuit means.

Landscapes

  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Power Engineering (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Control Of Vehicles With Linear Motors And Vehicles That Are Magnetically Levitated (AREA)
  • Linear Motors (AREA)
US53773A 1969-07-23 1970-07-10 High speed train utilizing hard superconductor Expired - Lifetime US3662689A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP44057702A JPS4937131B1 (de) 1969-07-23 1969-07-23

Publications (1)

Publication Number Publication Date
US3662689A true US3662689A (en) 1972-05-16

Family

ID=13063254

Family Applications (1)

Application Number Title Priority Date Filing Date
US53773A Expired - Lifetime US3662689A (en) 1969-07-23 1970-07-10 High speed train utilizing hard superconductor

Country Status (3)

Country Link
US (1) US3662689A (de)
JP (1) JPS4937131B1 (de)
FR (1) FR2053093B1 (de)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3837287A (en) * 1971-10-14 1974-09-24 Siemens Ag Magnetic suspension utilizing an elongated coil
US3844220A (en) * 1971-12-23 1974-10-29 Messerschmitt Boelkow Blohm Magnetic suspension and switching for vehicles
US3850109A (en) * 1973-04-30 1974-11-26 Massachusetts Inst Technology Transportation system employing magnetic levitation, guidance and propulsion
US3858521A (en) * 1973-03-26 1975-01-07 Canadian Patents Dev Magnetic levitation guidance system
US5388527A (en) * 1993-05-18 1995-02-14 Massachusetts Institute Of Technology Multiple magnet positioning apparatus for magnetic levitation vehicles
US5605100A (en) * 1990-10-23 1997-02-25 American Magley Technology Of Florida, Inc. Propulsion system for a magnetically movable vehicle
US6044770A (en) * 1990-10-23 2000-04-04 Park Square Technology, Ltd. Integrated high speed MAGLEV system
US6279728B1 (en) * 1998-07-20 2001-08-28 Norbert G Jung Electro-magnetic conveyor
DE102015001746A1 (de) * 2015-02-11 2016-08-11 Karlsruher Institut für Technologie Schienengebundene Magnetschwebebahn
CN111497633A (zh) * 2020-03-09 2020-08-07 上海交通大学 一种8字形线圈高温超导电动磁悬浮列车系统

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS61168111U (de) * 1985-04-06 1986-10-18
US5085149A (en) * 1990-04-06 1992-02-04 Houston Area Research Center Ground vehicle suspension and guidance and electromagnetic system thereof with multiple surface arcuate reaction rails
EP0520782B1 (de) * 1991-06-28 1996-11-20 Hitachi, Ltd. Supraleitender Verbundkörper und Schwebesystem

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3470828A (en) * 1967-11-21 1969-10-07 James R Powell Jr Electromagnetic inductive suspension and stabilization system for a ground vehicle

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3470828A (en) * 1967-11-21 1969-10-07 James R Powell Jr Electromagnetic inductive suspension and stabilization system for a ground vehicle

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3837287A (en) * 1971-10-14 1974-09-24 Siemens Ag Magnetic suspension utilizing an elongated coil
US3844220A (en) * 1971-12-23 1974-10-29 Messerschmitt Boelkow Blohm Magnetic suspension and switching for vehicles
US3858521A (en) * 1973-03-26 1975-01-07 Canadian Patents Dev Magnetic levitation guidance system
US3850109A (en) * 1973-04-30 1974-11-26 Massachusetts Inst Technology Transportation system employing magnetic levitation, guidance and propulsion
US5605100A (en) * 1990-10-23 1997-02-25 American Magley Technology Of Florida, Inc. Propulsion system for a magnetically movable vehicle
US6044770A (en) * 1990-10-23 2000-04-04 Park Square Technology, Ltd. Integrated high speed MAGLEV system
US5388527A (en) * 1993-05-18 1995-02-14 Massachusetts Institute Of Technology Multiple magnet positioning apparatus for magnetic levitation vehicles
US6279728B1 (en) * 1998-07-20 2001-08-28 Norbert G Jung Electro-magnetic conveyor
DE102015001746A1 (de) * 2015-02-11 2016-08-11 Karlsruher Institut für Technologie Schienengebundene Magnetschwebebahn
EP3256359B1 (de) * 2015-02-11 2021-03-31 Karlsruher Institut Für Technologie (KIT) Schienengebundene magnetschwebebahn
CN111497633A (zh) * 2020-03-09 2020-08-07 上海交通大学 一种8字形线圈高温超导电动磁悬浮列车系统
CN111497633B (zh) * 2020-03-09 2022-11-15 上海交通大学 一种8字形线圈高温超导电动磁悬浮列车系统

Also Published As

Publication number Publication date
JPS4937131B1 (de) 1974-10-05
FR2053093A1 (de) 1971-04-16
FR2053093B1 (de) 1973-03-16

Similar Documents

Publication Publication Date Title
US3662689A (en) High speed train utilizing hard superconductor
US3470828A (en) Electromagnetic inductive suspension and stabilization system for a ground vehicle
Jayawant Review lecture-electromagnetic suspension and levitation techniques
US4793263A (en) Integrated linear synchronous unipolar motor with controlled permanent magnet bias
US5094173A (en) Superconducting magnetic levitated train, train system method of controlling the same, and superconducting coil for magnetic levitated train
US3858521A (en) Magnetic levitation guidance system
US4979445A (en) Magnetically levitated vehicle with superconducting mirror sheets interacting with guideway magnetic fields
US3717103A (en) Low drag magnetic suspension system
Jayawant Electromagnetic suspension and levitation
US3841227A (en) Suspension system for a magnetic suspension railroad
JPH088724B2 (ja) 負荷の低摩擦輸送のための磁力装置
CN111873808A (zh) 一种超导电动-电磁混合磁悬浮列车
Borcherts et al. Baseline specifications for a magnetically suspended high-speed vehicle
Jayawant Electromagnetic suspension and levitation
CN217074052U (zh) 一种基于高温超导的磁悬浮列车
JP3815870B2 (ja) 磁気浮上式鉄道用推進・浮上・案内用地上コイル、磁気浮上式鉄道用推進・浮上・案内用地上コイルの接続方法、磁気浮上式鉄道の支持・案内用構造物、磁気浮上式鉄道の支持・案内用構造物の施工方法、磁気浮上式鉄道の推進・浮上・案内装置、磁気浮上式鉄道の推進・浮上・案内方法、磁気浮上式鉄道システム、磁気浮上式鉄道の集電システム、及び磁気浮上式鉄道の集電方法
US3892185A (en) Low drag magnetic suspension system
CN1339370A (zh) 永磁感应悬浮与导向装置
US3903809A (en) Electromagnetic suspension guidance system for a moving vehicle
US3780667A (en) Electro-magnetic system for the guided suspension of a moving vehicle
US5253592A (en) Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor
Kolm et al. Electromagnetic flight
US5275112A (en) Integrated null-flux suspension and multiphase propulsion system for magnetically-levitated vehicles
JPH07193914A (ja) 同期形リニアモーターカー
US4941406A (en) Magnetic and aerodynamic levitation vehicle