U.S. TRACKED AIR-CUSHION VEHICLE FINALLY GETS OFF THE GROUND

A GRANT WAS RECENTLY AWARDED BY THE DEPARTMENT OF TRANSPORTATION FOR THE PRELIMINARY STUDY OF A TRACKED AIR-CUSHION VEHICLE (TACV) THAT WILL SERVE LOS ANGELES INTERNATIONAL AIRPORT BY LATE 1972. THE DEMONSTRATION SYSTEM, TO BE POWERED BY LINEAR INDUCTION MOTOR (LIM) AT SPEEDS UP TO 150 MPH, WILL BE A STATE-OF-THE-ART VERSION OF THE ADVANCED 300-MPH RESEARCH VEHICLE NOW BEING DESIGNED BY GRUMMAN AEROSPACE CORP., BETHPAGE, N.Y. BY JOINING THE TACV WITH THE LIM, IT IS HOPED TO HAVE A VIRTUALLY NOISE-FREE, POLLUTION-FREE, 300-MPH VEHICLE CAPABLE OF IMPORTANT CONTRIBUTIONS IN MASS TRANSPORTATION. AT PRESENT, THE STATE-OF-THE-ART IN TACVS IS REPRESENTED BY THE FRENCH AEROTRAIN, WHICH IS CARRYING AS MANY AS 80 PASSENGERS ON DEMONSTRATION RUNS OVER AN 11-MILE TRACK OUTSIDE ORLEANS. THE VEHICLE IS PROPELLED BY TWO 15--HP GAS TURBINES THAT DRIVE A SINGLE PROPELLER, BUT IT WAS TESTED AT OVER 250 MPH WITH TWO RAM-AIR FANS DRIVEN BY JET ENGINES. THE FRENCH HAVE ALSO DEVELOPED A LIM-POWERED VERSION WHICH WAS TESTED REACHING A TOP SPEED OF NEARLY 110 MPH, GATHERING POWER FROM AN ALUMINUM RAIL THAT RUNS ALONGSIDE THE TRACK. THE LIM-POWERED AEROTRAIN ALSO USES A STRADDLED REACTION RAIL AS A GUIDEWAY, A SCHEME THAT EVOLVED FROM THE PROPELLER-DRIVEN VERSION, WHICH STRADDLES AN INVERTED-T GUIDEWAY. THE LOS ANGELES DEMONSTRATION PROJECT CALLS FOR AN ELEVATED GUIDEWAY RUNNING 16.3 MILES ALONG THE SAN DIEGO FREEWAY TO THE SAN FERNANDO VALLEY. THE POWER-CONDITIONING SYSTEM IS THE HEART OF THE LIM SYSTEM. THE GARRETT SYSTEM USES WAYSIDE POWER PICKED UP WHICH FIRST GOES THROUGH A PHASE-CONTROL RECTIFIER THAT CONVERTS THE AC TO DC, VARIABLE FROM 0 TO 9,000 V. A DC INDUCTOR IS USED AS A SMOOTHING REACTOR TO REMOVE THE WAVE RIPPLE. AN INVERTER CHANGES THE CURRENT TO VARIABLE-FREQUENCY AC, WHICH IS FED TO THE LIM. A FREE-RUNNING SYNCHRONOUS MACHINE CORRECTS THE LIM POWER FACTOR TO SLIGHTLY LEADING, ESTABLISHES A SINUSOIDAL WAVE SHAPE FOR THE INVERTER OUTPUT, AND PROVIDES THE REACTIVE POWER NECESSARY TO COMMUTATE THE INVERTER.

• Supplemental Notes:
  • Vol 41, No 14, PP 15-17, 4 PHOT
• Authors:
  • Parisi, A J
  • Maddox, D
• Publication Date: 1970-7-6

Media Info

• Serial:
  • Product Engineering
  • Publisher: McGraw-Hill, Incorporated

Subject/Index Terms

• TRT Terms: Air cushion vehicles; Air quality management; Alternating current motors; Demonstration projects; Gas turbines; Guides to information; Power converters; Public passenger vehicles; Railroad bridges; Railroad tracks; Turbine engines
• Uncontrolled Terms: Transit vehicles
• Old TRIS Terms: Guides
• Subject Areas: Highways; Planning and Forecasting; Public Transportation; Railroads;

Filing Info

• Accession Number: 00241384
• Record Type: Publication
• Files: TRIS
• Created Date: Sep 28 1970 12:00AM