Hovering Static Stability and Performance Experiments on Three- Dimensional Annular Jet Models
Abstract
Hovering static stability and performance experiments have been conducted with a series of three-dimensional annular jet models. The model planforms measured 40 by 20 in. and incorporated 1-in. thick jets operated at a total pressure of 41.5 pounds per square foot. Height-length ratios of 0.05 to 0.20 were investigated. Simple vertical and 45 degree inclined peripheral jets demonstrated static longitudinal stability at low heights and instability at high heights. Static lateral instability existed for both models at all heights. Convex and concave base shaping with a depth equal to 5% of the model length did not appreciably affect stability in either pitch or roll. A rigid skirt together with rigid base segmenting flaps of length equal to 5% of the model length were effective in augmenting longitudinal and lateral stability when they extended two-thirds the way to the ground, but were not very effective when they extended only half way to the ground. The order of increasing effectiveness of segmenting flap configuration was concentric, corner lobe, and centerline. The configurations investigated were not optimized for hovering performance. The configurations are, however, representative of compromises which occur due to forward flight considerations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1961
- Accession Number
- AD0282125
Entities
People
- B. H. Carmichael
- D. E. Mcnay