Hostname: page-component-78c5997874-t5tsf Total loading time: 0 Render date: 2024-11-10T04:25:08.628Z Has data issue: false hasContentIssue false
  • English
  • Français

Balance of Helm and Static Directional Stability of Yachts Sailing Close-Hauled

Published online by Cambridge University Press:  04 July 2016

John S. Letcher Jr
John S. Letcher Jr*
Affiliation:
California Institute of Technology , National Science Foundation Co-operative Graduate Fellow, Ae. Eng. Candidate, Dept. of Aeronautics
Get access Rights & Permissions [Opens in a new window]

Summary

An analysis is presented for equilibrium of yawing moments for a yacht sailing in the displacement mode in smooth water. The geometry of hull form and sail plan are quite unrestricted, although special attention is given throughout to currently popular types.

The free-surface flow is simplified by a reflection technique. In cases where the hull form is appropriate, the hull hydrodynamics are treated by lifting-line theory: in other cases slender-body theory is applied. The sail aerodynamics are treated by methods taken from aerofoil theory. Some design charts are given and computation methods are suggested for practical design calculations.

Static directional stability is treated theoretically and some general conclusions drawn regarding the influence of various characteristics on stability.

Where the theory has been applied, results have agreed with the available experimental data within the limits normally provided for adjusting balance of helm. Changes of balance with angle of heel and static stability have been given by the theory at least qualitatively correctly; experimental results are, however, not available for comparison.

Type
Research Article
Information
The Aeronautical Journal , Volume 69 , Issue 652 , April 1965 , pp. 241 - 248
Copyright
Copyright © Royal Aeronautical Society 1965

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1.DeYoung, John and Harper, C. W. Theoretical Symmetric Span Loading at Subsonic Speeds for Wings Having Arbitrary Plan Form. NACA Report No. 921, 1948.Google Scholar
2.Pitts, W. C., Nielsen, J. N., Kaattari, G. E. Lift and Centre of Pressure of Wing-Body-Tail Combinations at Subsonic, Transonic, and Supersonic Speeds. NACA Report 1307, 1957.Google Scholar
3.Multhopp, H. Zur Aerodynamik des Flugzeugrumpfes. Luftfahrtforschung 18, No. 2-3 (1941); NACA Technical Memorandum No. 1036, Aerodynamics of the Fuselage, 1942.Google Scholar
4.Jones, R. T. Properties of Low Aspect Ratio Pointed Wings at Speeds Above and Below the Speed of Sound. NACA Technical Report 835, 1946.Google Scholar
5.Thwaites, B.The Aerodynamic Theory of Sails. Part I— Two-Dimensional Sails. Proc. Roy. Soc, Series A, Vol. 261, pp. 402–422, 1961.Google Scholar
6.Nielsen, J. N.Theory of Flexible Aerodynamic Surfaces. J. Appl. Mech., Vol. 30, pp. 435–442, 1963.Google Scholar
7.Schrenk, O. A Simple Approximation Method for Obtain ing the Spanwise Lift Distribution. NACA Technical Memorandum 948; also Luftwissen, Bd. 7, Nr. 4, pp. 118-120, 1940.Google Scholar
8.Marchaj, C. A.Sailing Theory and Practice. Dodd, Mead and Company, 1964.Google Scholar