Performance potential and approximate cost estimate for three nonfriction braking systems are obtained. The systems are: the air retarder, the hydraulic retarder, and aerodynamic braking. It is shown that the air retarder and the hydraulic retarder have potential to develop full braking deceleration in a speed range from 250 MPH to 25 MPH. Because of its advantage over the hydraulic retarder in system weight, simplicity and cost, it is recommended that development of the air retarder be undertaken. Aerodynamic braking deceleration is highly dependent on projected braking area. Maximum frontal envelope considered was car frontal area plus an area enclosed by car width and extending three ft. above the roof. For this area, most of the energy of a 250 MPH train can be absorbed by aerodynamic braking. At speeds below 100 MPH (very approximately) aerodynamic braking must be supplemented by friction braking to obtain sufficient deceleration rates. Existing aerodynamic test data for longitudinally spaced braking surfaces are not sufficient to obtain accurate predictions of the friction braking crossover point and the aerodynamic braking deceleration rate. Therefore a wind tunnel test program is recommended. The report includes an extensive bibliography and references covering related aerodynamic material. (Author)

  • Corporate Authors:

    Cornell Aeronautical Laboratory

    Vehicle Research Department
    Buffalo, NY  United States 
  • Authors:
    • Cassidy, R J
    • Pleuthner, R L
    • Schenkel, F K
  • Publication Date: 1970-4

Media Info

  • Pagination: 204 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00039203
  • Record Type: Publication
  • Source Agency: National Technical Information Service
  • Report/Paper Numbers: CAL-YM-2811-K-3 Final Rpt
  • Contract Numbers: DOT-FR-9-0040
  • Files: TRIS
  • Created Date: Nov 24 1976 12:00AM