Hostname: page-component-cc8bf7c57-pd9xq Total loading time: 0 Render date: 2024-12-11T17:28:49.921Z Has data issue: false hasContentIssue false
  • English
  • Français

Aerodynamic modelling of fin stabilised underslung loads

Published online by Cambridge University Press:  27 January 2016

K. Enciu  and
A. Rosen
K. Enciu*
Affiliation:
Technion – Israel Institute of Technology, Faculty of Aerospace Engineering, Haifa, Israel
A. Rosen*
Affiliation:
Technion – Israel Institute of Technology, Faculty of Aerospace Engineering, Haifa, Israel
*
[email protected]
[email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Box-like slung loads exhibit periodic yaw response instabilities, while carried externally by a helicopter. When coupled with the slung load longitudinal and lateral pendulum motions, these instabilities result in significant pendulum oscillations of the load. High amplitude oscillations lead in many cases to the limiting of a load’s flight envelope. Using wind tunnel and flight tests, rear mounted fins were previously demonstrated as efficient means for stabilisation of a problematic load. However, the lack of a proper analytical model of the stabilised load’s aerodynamic characteristics, led to a trial and error development process, without an appropriate physical understanding of the stabilisation problem. The present paper describes a method for the aerodynamic modeling of fins stabilised slung loads based on a limited number of simple static wind-tunnel tests. The resulting database is incorporated in a dynamical slung load simulation that shows good agreement with dynamic wind-tunnel tests. The applicability of the proposed method is demonstrated, by the calculation of stabilised loads aerodynamic databases for interim fin inclination angles not covered by tests.

Type
Research Article
Information
The Aeronautical Journal , Volume 119 , Issue 1219 , September 2015 , pp. 1073 - 1103
Copyright
Copyright © Royal Aeronautical Society 2015

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.Cicolani, L.S., Raz, R., Rosen, A., Gordon, R., Cone, A., Theron, J.N., Lusardi, J., Tirchler, M. and Robinson, D.Flight test, simulation and passive stabilization of a cargo container slung load in forward flight, American Helicopter Society International 63rd Annual Forum, 1-3 May 2007, 3, pp 2177–2206, Virginia Beach, VA, USA.Google Scholar
2.Sheldon, D.F.Appreciation of dynamic problems associated with external transportation of loads from a helicopter-state of art, Vertica, 1977, 1, (4), pp 281–290.Google Scholar
3.Pryor, J. and Sheldon, D.F.Phase 2 – a study in depth of a single point and two point lateral and tandem suspension of rectangular box loads, May 1973, RMCS Technical Note AM 38, Royal Military College of Science.Google Scholar
4.Simpson, A. and Flower, J.W. Unsteady aerodynamics of oscillating containers and application to the problem of dynamic stability of helicopter underslung loads, May 1978, AGARD CP 235.Google Scholar
5.Watkins, T.C., Sinacori, J.B. and Kesler, D.F.Stabilization of externally slung helicopter loads [Final Report, 1 Jul 1972-31 Oct 1973], Final Report, August 1974, USAAMRDL-TR-74-42, US Army MRDL.Google Scholar
6.Sampath, P.Dynamics of a Helicopter-Slung Load System, PhD thesis, April 1980, University of Maryland, USA.Google Scholar
7.Greenwell, D.I.Modelling of static aerodynamics of helicopter underslung loads, 2008, 26th Congress of International Council of the Aeronautical Sciences, 14-19 September 2008,, ICAS 2008-5.11.2, Anchorage, AK, USA.Google Scholar
8.Theron, J.N., Duque, E.P.N. and Cicolani, L.A CFD Study of the aerodynamics of a 6 × 6 × 8 foot cargo container suspended beneath a helicopter, Part I: Aerodynamics of the stationary container, October 2007, AFDD/TR-07-001, US Army AFDD.Google Scholar
9.Cicolani, L.S., Cone, A., Theron, J.N., Robinson, D., Lusaardi, J., Tischler, M.B., Rosen, A. and Raz, R.Flight test and simulation of a cargo container slung load in forward flight, J American Helicopter Soc, 2009, 54, (3), pp 0320061-03200618.CrossRefGoogle Scholar
10.Mnatri, R., Ragnav, V., Koukol, B., Komerath, N. and Smith, M.Study of factors driving pitch, roll, and yaw coupling in bluff body aerodynamics, 2011, 41st AIAA Fluid Dynamics Conference and Exhibition, 27-30 June 2011, Honolulu, Hawaii, USA.Google Scholar
11.Prosser, D.T. and Smith, M.J.Characterization of flow around rectangular bluff bodies at angle of attack, Physics Letters A, August 2012, 376, (45), pp 3204-7.Google Scholar
12.Liu, D.T.In-flight stabilization of externally slung helicopter loads, Final Report, June 1970-June 1972, USAAMRDL Tech. Report 73-5, May 1973, US Army Air Mobility Research and Development Labs, Fort Eustis Directorate, Fort Eustis, VA, USA.Google Scholar
13.Asseo, S.J. and Whitback, R.F.Control requirements for sling-load stabilization in heavy lift helicopters, J American Helicopter Soc, July 1973, 18, (3), pp 23–31.Google Scholar
14.Micale, E.C. and Poli, C.Dynamics of slung bodies utilizing a rotating wheel for stability, J Aircr, 1973, 10, (12), pp 760–763.CrossRefGoogle Scholar
15.Feaster, L.L.Dynamics of a Slung Load, PhD thesis, June 1975, Massachusetts University, Amherst, MA, USA.Google Scholar
16.Pardue, M.D. and Shaughnessy, J.D. Design and analysis of an active jet control system for helicopter sling loads, January 1979, NASA TP 1397.Google Scholar
17.Nagabhushan, B.L.Optimal controller design for a helicopter using its lower order dynamic model, American Institute of Aeronautics and Astronautics, Aircraft Design, Systems and Technology Meeting, 17-19 October 1983, Fort Worth, TX, USA.Google Scholar
18.Raz, R., Rosen, A. and Ronen, N.T.Active aerodynamic stabilization of a helicopter sling-load system, J Aircr, September 1989, 26, (9), pp 822–828.CrossRefGoogle Scholar
19.Ehlers, G.E.Hi-fidelity Simulation and Prediction of Helicopter Single Point External Load Stabilization, MSc thesis, September 2001, Naval Postgraduate School, Monterey, CA, USA.Google Scholar
20.Hamers, M. and Bouwer, G.Flight director for helicopter with slung load, 30th European Rotorcraft Forum, 14-16 September 2004, pp 795–804, Marseilles, France.Google Scholar
21.Hamers, M. and Bouwer, G.Helicopter slung load stabilization using a flight director, American Helicopter Society International 60th Annual Forum, 1-3 June 2005, 1, pp 768–780, Grapevine, TX, USA.Google Scholar
22.Hamers, M.Flight director for handling of helicopter sling loads, 2005, 31st European Rotorcraft Forum, 13-15 September 2005, pp 119.1–119.11, Florence, Italy.Google Scholar
23.Hamers, M., Von Hinuber, E. and Richter, A.Flight director for slung load handling – First experiences on Ch53, 33rd European Rotorcraft Forum, 11-13 September 2007, 4, pp 2557–2566, Kazan, Russia.Google Scholar
24.Raz, R., Rosen, A., Carmeli, A., Lusardi, J., Cicolani, L.S. and Robinson, L.T.C.D.Wind tunnel and flight evaluation of stability and passive stabilization of cargo container slung load, American Helicopter Society International 64th Annual Forum, 29 April-1 May 2008, 2, pp 1097–1126, Montreal, Canada.Google Scholar
25.Raz, R., Rosen, A., Cicolani, L.S., Lusardi, J., Gassaway, B. and Thompson, T.Using wind tunnel tests for slung loads clearance, 67th American Helicopter Society International Annual Forum, 3-5 May 2011, pp 3110–3137, Virginia Beach, VA, USA.Google Scholar
26.Ringland, R.F., Tusschler, M.B., Jex, H.R., Emmen, R.D. and Ashkenas, I.L.Flight dynamics analysis and simulation of heavy lift airships. Volume 2: Technical Manual [Final Report, Sep 1979-Dec 1982], December 1982, NASA-CR-166471.Google Scholar
27.Wick, B.H. Study of the subsonic forces and moments on an inclined plate of infinite span, June 1954, NACA TN 3221.Google Scholar
28.Hoerner, S.F.Fluid-Dynamic Drag, 1965, Published by the Author, Bakersfield, CA, USA.Google Scholar
29.Enciu, K. and Rosen, A.Aerodynamic modeling of fn stabilized underslung loads, September 2013, TAE 989, Faculty of Aerospace Engineering, TECHNION – Israel Institute of Technology.Google Scholar
30.Rosen, A., Cecutta, S. and Yaffe, R.Wind tunnel tests of cube and Conex models, November 1999, TAE 844, Faculty of Aerospace Engineering, TECHNION – Israel Institute of Technology.Google Scholar
31.Raz, R., Rosen, A., Carmeli, A., Lusardi, J., Cicolani, L.S. and Robinson, D.Wind tunnel and flight evaluation of passive stabilization of a cargo container slung load, J American Helicopter Soc, July 2010, 55, (3), pp 0320011–03200118.Google Scholar