DMCA
A Reassessment of Heavy-Duty Truck
BibTeX
@MISC{Materials_areassessment,
author = {Analytical Services Materials and Edwin J. Saltzman and Robert R. Meyer},
title = {A Reassessment of Heavy-Duty Truck},
year = {}
}
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Abstract
demonstrating means for reducing the drag of trucks, buses, and motor homes. Numerous configurations were evaluated using a box-shaped test van, a two-axle truck, and a tractor-semitrailer combination. Results from three configurations of the test van are of interest now in view of a trucking industry goal of a 0.25 drag coefficient for tractor-semitrailer combinations. Two test van configurations with blunt-base geometry, similar to present day trucks (one configuration has square front corners and the other has rounded front corners), quantify the base drag increase associated with reduced forebody drag. Hoerner's equations predict this trend; however, test van results, reinforced by large-scale air vehicle data, indicate that Hoerner's formula greatly underestimates this dependence of base drag on forebody efficiency. The demonstrated increase in base drag associated with forebody refinement indicates that the goal of a 0.25 drag coefficient will not be achieved without also reducing afterbody drag. A third configuration of the test van had a truncated boattail to reduce afterbody drag and achieved a drag coefficient of 0.242. These results are included here and references are identified for other means of reducing afterbody drag.
Keyphrases
afterbody drag drag coefficient heavy-duty truck test van base drag front corner tractor-semitrailer combination test van configuration forebody drag trucking industry goal third configuration demonstrated increase blunt-base geometry numerous configuration forebody refinement box-shaped test van motor home two-axle truck forebody efficiency present day truck large-scale air vehicle data van result base drag increase
