Hostname: page-component-78c5997874-xbtfd Total loading time: 0 Render date: 2024-11-04T11:08:16.860Z Has data issue: false hasContentIssue false
  • English
  • Français

On a pitch control law for a constant glide slope through windshears

Published online by Cambridge University Press:  04 July 2016

L. M. B. C. Campos
L. M. B. C. Campos*
Affiliation:
Instituto Superior Técnico1096 Lisboa Codex, Portugal
Get access Rights & Permissions [Opens in a new window]

Summary

The equations of motion of an aircraft flying at a constant glide slope (Fig. 3), in the presence of arbitrary head- or tailwinds, and up- or downflows is considered. The equations are integrated analytically, in the case of an aircraft initially on a steady flight, perturbed by winds of ‘moderate’ strength, in the sense that the wind velocity is not negligible compared to the aircraft's steady speed, but the ratio of their squares is much smaller than unity. The case of an approach through a downburst (Fig. 1), leads to winds which can be simplified to a one-period sinusoidal wind along the flight path, changing from head- to tailwind, at the peak of a superimposed downflow (Fig. 2), of half-period sinusoidal shape, and this is discussed in some detail. Data sheets are presented for three combinations of amplitudes of the head-to-tailwind and downflow; each contains plots of the scheduling of incidence that exactly cancels windshear effects, and of the groundspeed a'nd airspeed profiles which will keep the aircraft flying along the original glide slope. Each plot is given for a range of values of the windshear susceptibility parameter, representing aircraft with small or large inertia, with high or low approach speeds, including light aircraft, jet fighters and large transports; the cancellation of windshear effects isachievable only if the incidence schedule lies wholly below the stall limit. Since the rotational inertia of the aircraft is neglected, the short period mode is absent, and the pitch control acts to cancel the ‘phugoid’ instability induced on the aircraft by the wind profiles typical of a microburst.

Type
Research Article
Information
The Aeronautical Journal , Volume 93 , Issue 928 , October 1989 , pp. 290 - 300
Copyright
Copyright © Royal Aeronautical Society 1989 

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. Bochis, V. Dynamics of an aircraft in a windshear of arbitrary direction, AlAA J Guidance, 7, 615–619.Google Scholar
2. Frost, W., Cosby, B. and Camp, D. W. Flight through thunderstorm outflow, AlAA J Aircraft, 16, 11–15.Google Scholar
3. Ektin, B. AIAA Wright Brothers lecture, 1980: The Turbulent Wind and Its Effect on Flight, University of Toronto Aerospace Department, Review 44.Google Scholar
4. Schanzer, G. Influence of Windshear of Flight Safety, AGARD, CP-347, paper 12.Google Scholar
5. Schlickenmeier, H. FAA integrated windshear program, Second International Conference on Aviation Safety, Toulouse, 1986.Google Scholar
6. Clodman, J., Muller, F. B. and Morrisey, B. G. Wind regime in the lowest one hundred metres, as related to aircraft take-offs and landings, World Health Organisation Conference, London 1968, p28–43.Google Scholar
7. Glazunov, V. G. and Guerava, V. Z. A model of windshear in the lower 50 metre section of the glide path, from data of low inertia measurements. Math Lond Lib Sci Tech, NLL-M-23036, 1973.Google Scholar
8. Sweezy, W. B., Moninger, W. R. and Strauch, R. G. Simulation of Radar-Measured Doppler Velocity Profiles in Low-Level Windshear, FAA, RD-78-46.Google Scholar
9. Zrnic, D. S., Doviak, R. J., Lee, J. T. and Eilts, M. D. Weather phenomena that affect aviation, Proceedings of the 2nd International Conference on Aviation Safety, Toulouse, 1986.Google Scholar
10. Woodfield, A. A. and Vaughan, J. M. Using an airborne CO2 CW-laser for free stream airspeed and windshear measurements. AGARD Conference Proceedings, CP-373, Paper 22, 1984.Google Scholar
11. Vorsmann, P. An on-line realisation for precise wind vector measurements on board the Do 28 research aircraft. International Congress Aerospace Science, Paper 84-5.10.1.Google Scholar
12. Woodfield, A. A. and Woods, J. F. Windshear From Headwind Measurements on British Airways B747-236 Aircraft. RAE, TM-409, 1981.Google Scholar
13. Zhu, S. and Etkin, B. A Fluid Dynamic Model of a Downburst, University of Toronto, Aerospace Department, Report 271, 1983.Google Scholar
14. Woodfield, A. A. and Woods, J. F. Worldwide Experience With Wind Shear During 1981-1982. AGARD, CP-347, Paper 11.Google Scholar
15. Jones, J. G. Modelling of Gust and Windshear for Aircraft Assessment and Certification, RAE, 1976.Google Scholar
16. Fujita, T. T. Microburst Windshear at New Orleans International Airport, Kenner, Louisiana, on 9 July 1982, University of Chicago, SMRP Research Paper 199, 1983.Google Scholar
17. Diederich, F. W. Response of an Airplane to Random Atmospheric Disturbances, NACA TN-3910, 1957.Google Scholar
18. Brockhaus, R. and Wuest, P. Open Loop Compensation of Windshear Effects in Low Level Flight, AGARD CP-240, Paper 19, 1978.Google Scholar
19. Van Der Waart, J. C. Aircraft Response to Windshears and Down Draughts, AGARD, CP-260, Paper 16, 1979.Google Scholar
20. Leurs, J. K. and Reeves, J. B. Effect of Shear on Aircraft Landing, NASA, CR-2287, 1973.Google Scholar
21. Cavalcanti, S. G. Critical Conditions of the Automatic Control of Landing From Decision Height in Variable Winds, University of Toronto Aerospace Department, Report 284, 1984.Google Scholar
22. Schanzer, G. The Effect of Gust and Windshear for Automatic STOL Approach and Landing, AGARD, CP-140, 1973.Google Scholar
23. Reid, L. D., Markov, A. B. and Graf, W. O. The Application of Techniques for Predicting STOL Aircraft Response to Windshear and Turbulence During Landing Approach, University of Toronto Aerospace Department, Report 215, 1977.Google Scholar
24. Bray, R. S. A. A Method of Three-Dimensional Modelling of Windshear Environments for Flight Simulator Applications, NASA TM-85969, 1984.Google Scholar
25. Schanzer, G. Dynamic Energy Transfer Between Wind and Aircraft, International Congress on Aerospace Science, Paper 82-3.4.1.Google Scholar
26. Campos, L. M. B. C. On the influence of atmospheric disturbances on aircraft aerodynamics. Aeronaut J, June-July 1984, 88, (876), 257–264.Google Scholar
27. Campos, L. M. B. C. On aircraft flight performance in a perturbed atmosphere. Aeronaut J, October 1986, 90 (898), 302–312.Google Scholar
28. Campos, L. M. B. C. On the disturbance intensity as an indicator of aircraft performance degradation in a perturbed atmosphere. Second International Conference on Aviation Safety, Toulouse, 1986.Google Scholar
29. Campos, L. M. B. C. On the inverse phugoid problem as an instance of non-linear stability in pitch, Aeronaut J, August-September 1989, 93, (927).Google Scholar
30. Landau, L. D. and Lifshitz, E. F. Electrodynamics of continuous media, Pergamon, 1967.Google Scholar
31. Batchelor, G. K. Fluid Mechanics, Cambridge University Press.Google Scholar
32. Von Mises, R. Theory of flight. McGraw-Hill 1945.Google Scholar
33. Duncan, W. J. Principles of control and stability of aircraft, Cambridge University Press, 1952.Google Scholar
34. Lecomte, P. Mécanique du Vol, Dunod, 1962.Google Scholar
35. Etkin, B. Dynamics of flight stability and control, Wiley, 1974.Google Scholar
36. Babister, A. W. Aircraft dynamic stability and response. Oxford University Press, 1980.Google Scholar
37. Campos, L. M. B. C. Funcoes complenas e campos potenciais Calouste Gulbenkian Foundation, 1988.Google Scholar
38. Lighthill, M. J. Introduction to fluid mechanics, Oxford University Press, 1987.Google Scholar
39. Milne-Thomas, L. M. Theoretical aerodynamics, MacMillan 1958.Google Scholar
40. Pontriaguine, L. Equations differentielles ordinaires, Editions Mir, 1975.Google Scholar
41. Forsyth, A. R. Treatise of differential equations. MacMillan 1885, 6th ed. 1927.Google Scholar
42. Lanchester, F. W. Aerodonetics, Constable 1908.Google Scholar