AIR RESISTANCE OF MOTOR VEHICLES

A NEW AND DIRECT METHOD OF MEASUREMENT OF THE AIR RESISTANCE OF A MOTOR VEHICLE IS DESCRIBED. A FLOATING ENVELOPE WAS BUILT AROUND A FULL-SIZED CAR. THE ENVELOPE WAS MADE OF PRESSED WOOD PANELS FASTENED TO A LIGHT WOOD FRAME WELL BRACED WITH WOOD BRACES AND PIANO WIRE WITH AIRPLANE TYPE TURN BUCKLES. THE FRAME WORK OF THE ENVELOPE IS SUPPORTED BY STEEL TUBING, WHICH CAN MOVVE FORWARD OR BACKWARD ON GROOVED ROLLERS. THE ENVELOPE IS THUS FREE TO MOVE FORWARD OR BACKWARD SEVERAL INCHES ON THE BALL BEARING ROLLERS. AS THE CAR INSIDE THE ENVELOPE IS DRIVEN FORWARD THE AIR PRESSURE TENDS TO DRIVE THE ENVELOPE TO THE REAR. THIS MOTION IS RESTRAINED ONLY BY PIANO WIRE CONNECTING THE ENVELOPE TO A DRAW BAR DYNAMOMETER MOUNTED IN THE REAR OF THE CAR. THIS WIRE TRANSMITS FROM THE CAR INSIDE, TO THE ENVELOPE, THE FORCE REQUIRED TO DRIVE THE ENVELOPE FORWARD THROUGH THE AIR. TESTS WERE CONDUCTED ON A FOUR MILE COURSE OF APPROXIMATELY LEVEL AND SMOOTH CONCRETE ROADS. HIGH SPEED RUNS WERE TIMED OVER THE COURSE WITH A MINIATURE WEATHER BUREAU STATION MEASURING WIND VELOCITY AND DIRECTION, AND AIR TEMPERATURE, PRESSURE, AND HUMIDITY. FIGURES PRESENT THE VALUES OF THE AIR RESISTANCE PLOTTED ON RECTANGULAR COORDINATES AGAINST CAR SPEED. RESULTS WERE COMPARED WITH WIND TUNNEL TESTS ON THE SAME BODY FORM.

  • Supplemental Notes:
    • Vol 12, Pt 1, PP 66-75, 8 FIG, 2 TAB
  • Authors:
    • Lay, W E
  • Publication Date: 1933

Media Info

  • Monograph Title: Proceedings of the Twelfth Annual Meeting of the Highway Research Board Held at Washington, D.C. December 1-2, 1932. Part I: Reports of Research Committees and Papers
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00223301
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jun 1 1971 12:00AM