RESEARCH ON VTOL WATER HOVER EFFECTS, INCLUDING THE EFFECTS OF WIND AND WAVES
Abstract
Very little is known about the problems associated with a VTOL aircraft hovering over a water surface. Some of the more important of these unknown effects appear to be the effects of surface winds and waves on the stability and control characteristics of the hovering airplane, the effects of the airplane's downwash on the water surface, and the effects of surface winds and waves on the spray generated by the airplane's downwash. In order to examine these seemingly more important effects, a special model testing facility has been built. This facility permits a model simulating a hovering airplane to be tested as the facility generates waves of variable heights and lengths on the water surface below the model test station. The facility can also generate a surface wind. During this test a model of a tilting VTOL airplane with four propellers was tested as it simulated hover at varying heights and disk loadings above the variable water surface conditions. The effects of water waves on the forces and moments felt by the hovering model were found to be negligible, and the effects of the surface wind on the forces and moments were found to be as would be predicted with a negligible effect of waves even with the surface wind. By contrast, it was found that the waves and the surface wind both had significant effects on the effects of the airplane's downwash on the water surface and the spray generated around the model. Comparison of some of the spray patterns found in this test program with results of full scale airplane tests indicate that these results of the model tests correlate well with the limited data available from the actual airplane tests.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1968
- Accession Number
- AD0668714
Entities
People
- Keith R. Marsh
Organizations
- Vought