HINGE MOMENT REDUCTION FOR THE AG(EH) MAIN STRUT-POD-FOIL ASSEMBLY BY USE OF TRAILING EDGE TABS

Hydrodynamic loading on a 1/12th scale model of the AG(EH) main strut-pod-foil was experimentally examined at various velocities, depth of hydrofoil submergence, strut-pod pitch angles, and foil angles of attack. The results, which are in agreement with previous experiments, show that the lift center of pressure at zero angle of attack for this particular foil (aspect ratio = 3, taper ration = 0.3, and leading edge sweep angle - 0.724 rad or 41.5 deg) is located at 70 to 90 percent of the mean geometric chord. Thus, the experimental results could not be compared directly to the empirical two-dimensional theory that was developed since it had been assumed that this lift acted at midchord. Various families of fixed tab/flaps were added to the trailing edge of the foil to determine the effectiveness of such tab/flaps in reducing the foil pitching moment around the foil hinge. It was shown that such tab/flaps can significantly reduce this moment but at a drag penalty. For example, for the particular strut-pod-foil system evaluated, to reduce the moment to zero would result in a 12 to 15 percent increase in drag. (Author)

• Corporate Authors:

  David Taylor Naval Ship R&D Center

  Ship Performance Department
  Bethesda, MD  United States  20084
• Authors:
  • Coder, D W
  • Norton, R M
  • Wisler, B B
• Publication Date: 1976-6

Media Info

• Pagination: 201 p.

Subject/Index Terms

• TRT Terms: Airfoils; Hydrofoils; Performance; Struts
• Uncontrolled Terms: Control surfaces
• Old TRIS Terms: Flapped hydrofoils
• Subject Areas: Marine Transportation; Vehicles and Equipment;

Filing Info

• Accession Number: 00147883
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: SPD-332-04 Depart Rpt
• Files: TRIS
• Created Date: Feb 16 1977 12:00AM