Calculation of Aerodynamic Forces on a Propeller in Pitch or Yaw
Abstract
An analysis has been made to determine the applicability of existing propeller theory and the theory of oscillating airfoils to the problem of determining the magnitude of the forces on propellers in pitch or yaw. Strip calculations including the Goldstein correction factors and using compressible airfoil characteristics were first made as though steady- state conditions existed successively at several blade positions of the propeller blades during one revolution. A theory of oscillating airfoils in pulsating incompressible linearized potential flow was then considered from which it was possible to determine factors which would mod- ify the forces as calculated under the assumption of steady-state compressible flow. Comparisons of the steady-state calculations with experimental results show that the magnitude of the force changes experienced by the blades can be predicted with satisfactory ac9uracy. Results of calculations made by the oscillating theory indicate that the actual forces on the blade may be somewhat lower than the values calculated by the steady- state method. It was not possible to establish this concThusion definitely because of the lack of sufficient experimental data for comparison. The turning moment on the shaft of a two-blade propeller fluctuates between approximately zero and its maximum value twice per revolution. For the operating condition investigated the turning moment on the shaft of a three-blade propeller remains nearly constant at about 7% percent of the maximum value attained with the two-blade propeller.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1952
- Accession Number
- ADA380456
Entities
People
- Jean Gilman Jr.
- John L. Crigler
Organizations
- National Aeronautics and Space Administration