ROAD RESISTANCE OF LARGE TRANSPORT TRUCKS

A ROAD TEST PROCEDURE, USING COASTDOWN TESTS AT VARIOUS LOADS, HAS BEEN DEVELOPED FOR MEASURING SEPARATELY THE AIR DRAG AND TIRE DRAG FORCE OF A TRUCK. THE RAYON CORD TIRES TESTED SHOWED A DRAG FORCE OF 8.2 LB PER 1,000-LB LOAD, AS MEASURED BY THESE COASTDOWN TESTS, AND A DRAG FORCE OF 8.25 LB PER 1,000-LB LOAD AS MEASURED BY TIRE DOLLY TOWING TESTS, INDICATING THAT THE COASTDOWN PROCEDURE YIELDS ESSENTIALLY CORRECT RESULTS. AIR DRAG COEFFICIENTS MEASURED BY THE COASTDOWN TEST PROCEDURE FOR THE FOUR DIFFERENT TRUCK- TRAILER COMBINATIONS TESTED VARIED BETWEEN 0.8 AND 1.2, BEING RELATIVELY CONSTANT FOR ANY ONE TRUCK AND TRAILER. THESE DRAG COEFFICIENTS ARE OF THE SAME ORDER OR MAGNITUDE AS THOSE MEASURED FOR TRUCK MODELS IN WIND TUNNEL TESTS BY FLYNN AND KYROPOULOS. BECAUSE THE AIR DRAG COEFFICIENTS OF FULL-SCALE TRUCKS HAVE NOT PREVIOUSLY BEEN MEASURED, OTHER COMPARISONS OF THE FOREGOING RESULTS CANNOT BE MADE. TO FILL IN THIS GAP, TESTS ARE CURRENTLY UNDER WAY TO MEASURE THE AIR DRAG COEFFICIENTS OF FULL-SCALE TRUCKS USING A RAILWAY FLAT CAR TRAIN AS A MOVING TEST BED. /AUTHOR/ REFERENCES' TRUCK AERODYNAMICS, H. FLYNN AND P. KYROPOULOS, SAE PREPRINT 284A, JANUARY 1961.

Media Info

  • Media Type: Print
  • Features: Figures; References; Tables;
  • Pagination: pp 64-88
  • Monograph Title: Traffic and operations - general 1963
  • Serial:

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Filing Info

  • Accession Number: 00222517
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Oct 28 1994 12:00AM