ROLL STABILITY OF GROUND EFFECT MACHINESTHICK ANNULAR JET AND PLENUM TYPES
Abstract
An electrically powered model Ground Effect Machine, first arranged with a thick annular jet and second as a simple plenum chamber, was used in an investigation of the roll stability in hovering flight. The lift, height, and power relationship was determined and the restoring moment and side force due to inclination to the ground were measured. In the annular jet version, the restoring moment was proportional to roll angle and changed little with flying height. The side force on body axes was zero at heights less than the jet width and slightly negative (that is, towards, the high side of the machine) at greater flying height. The plenum chamber version had little or no restoring moment but had positive side force, expressible as a rotation of the lift vector through an angle greater than the roll angle. This effect increased with height, from a ratio 1.14 up to 1.8 at the greatest height tested. Both versions were dynamically stable in their various ways and were little affected by the variation in CG height. The addition of outward-curved fairings at the lower edges of the plenum chamber made the model strongly stable, with a finite restoring moment and a lift vector rotation to twice the roll angle, but reduced the hover height.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1965
- Accession Number
- AD0617129
Entities
People
- Alastair Anthony
- David A. Shaffer
- Norman K. Walker
- Richard Brooks