Accession Number:

AD0750179

Title:

A Theoretical Analysis of the Tip Relief Effect on Helicopter Rotor Performance

Descriptive Note:

Final rept. Oct 1970-Oct 1971

Corporate Author:

AEROPHYSICS CO WASHINGTON DC

Personal Author(s):

Report Date:

1972-08-01

Pagination or Media Count:

84.0

Abstract:

A theoretical method is derived whereby the effect of the compressible three-dimensional relief on the torque required for a helicopter rotor may be calculated. The complementary wing approach is used to represent the relief effect. The effect of the wing which complements a finite wing to make it an infinite wing may be found as a reduction in the free-stream velocity. This approach was applied to fixed wings by Anderson and is extended here for application to helicopter rotors. By using a simplified blade element analysis, the magnitude of the change in torque due to tip relief has been calculated and compares well with test results. The method to use the tip relief calculation in more complex blade element computer programs is described.

Subject Categories:

  • Helicopters
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE