Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-10T20:03:30.735Z Has data issue: false hasContentIssue false

Consideration of structural constraints in passive rotor blade design for improved performance

Published online by Cambridge University Press:  04 July 2016

J.W. Lim*
Affiliation:
US Army Aviation Development Directorate – AFDD, Aviation & Missile Research, Development & Engineering Center, Research Development and Engineering, Command (RDECOM), Ames Research Center, Moffett Field, California, USA

Abstract

This design study applied parameterisation to rotor blade for improved performance. In the design, parametric equations were used to represent blade planform changes over the existing rotor blade model. Design variables included blade twist, sweep, dihedral and the radial control point. Updates to the blade structural properties with changes in the design variables allowed accurate evaluation of performance objectives and realistic structural constraints – blade stability, steady moments (flap bending, chord bending and torsion) and the high-g manoeuvre pitch link loads. Performance improvement was demonstrated with multiple parametric designs. Using a parametric design with advanced aerofoils, the predicted power reduction was 1.0% in hover, 10.0% at μ = 0.30 and 17.0% at μ = 0.40, relative to the baseline UH-60A rotor, but these were obtained with a 35% increase in the steady chord bending moment at μ = 0.30 and a 20% increase in the half peak-to-peak pitch link load during the UH-60A UTTAS manoeuvre. Low vibration was maintained for this design. More rigorous design efforts, such as chord tapering and/or structural redesign of the blade cross section, would enlarge the feasible design space and likely provide significant performance improvement.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society 2016 

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

REFERENCES

1. Lim, J.W. and Chopra, I. Aeroelastic optimization of a helicopter rotor using an efficient sensitivity analysis, J. Aircraft, January 1991, 28, (1), pp 2937.Google Scholar
2. Celi, R. and Friedmann, P.P. Structural optimization with aeroelastic constraints of rotor blades with straight and swept tips, AIAA J., 1990, 28, (5), pp 928936.Google Scholar
3. Friedmann, P.P. Helicopter vibration reduction using structural optimization with aeroelastic/multidisciplinary constraints – a survey, J. Aircraft, January 1991, 28, (1), pp 821.Google Scholar
4. Celi, R. Recent applications of design optimization to rotorcraft – a survey, J. Aircraft, January-February 1999, 36, (1), pp 176189.Google Scholar
5. Ganguli, R. Survey of recent developments in rotorcraft design optimization, J. Aircraft, May-June 2004, 41, (3), pp 493510.Google Scholar
6. Imiela, M. and Wilke, G. Passive blade optimization and evaluation in off-design conditions, 39th European Rotorcraft Forum Proceedings, 3-5 September 2013, Moscow, Russia.Google Scholar
7. Johnson, C.S. and Barakos, G.N. Optimising aspects of rotor blades in forward flight, Proceedings of the 49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 4-7 January 2011, Orlando, Florida, US.Google Scholar
8. Min, B.Y., Sankar, L.N., Collins, K. and Brentner, K.S. CFD-CSD coupled study in the BVI characteristics of a saw-tooth blade planform, American Helicopter Society 67th Annual Forum Proceedings, 3-5 May 2011, Virginia Beach, Virginia, US.Google Scholar
9. Leon, E.R., Le Pape, A., Desideri, J., Alfano, D. and Costes, M. Concurrent aerodynamic optimization of rotor blades using a Nash game method, American Helicopter Society 69th Annual Forum Proceedings, 21-23 May 2013, Phoenix, Arizona, US.Google Scholar
10. Mishra, A., Karthik, M., Mavriplis, D. and Sitaraman, J. Time-dependent adjoint-based aerodynamic shape optimization applied to helicopter rotors, American Helicopter Society 70th Annual Forum Proceedings, 20-22 May 2014, Montreal, Canada.Google Scholar
11. Naik, K.R., Economon, T.D., Colonno, M.R., Palacios, F. and Alonso, J.J. A time-spectral adjoint formulation for shape optimization of helicopters in forward flight, American Helicopter Society 69th Annual Forum Proceedings, 21-23 May 2013, Phoenix, Arizona, US.Google Scholar
12. Ortun, B., Bailly, J., des Rochettes, H.M. and Delrieux, Y. Recent advances in rotor aerodynamic optimization, including structural data update, 5th Decennial American Helicopter Society Specialists’ Conference Proceedings, 22-24 January 2014 San Francisco, California, US.Google Scholar
13. Potsdam, M., Yeo, H. and Johnson, W. Rotor airloads prediction using loose aerodynamic/structural coupling, J. Aircraft, May-June 2006, 43, (3), pp 732742.Google Scholar
14. Adams, B. The Dakota toolkit for parallel optimization and uncertainty analysis, SIAM Conference on Optimization Proceedings, May 2008, Boston, Massachusetts, US.Google Scholar
15. Johnson, W. Rotorcraft aerodynamic models for a comprehensive analysis, Proceedings of the 54th Annual Forum of the American Helicopter Society, 20-22 May 1998, Washington, D.C., US.Google Scholar
16. Brocklehurst, A. and Barakos, G.N. A review of helicopter rotor blade tip shapes, Progress in Aerospace Sciences, 2013, 56, pp 3574.Google Scholar
17. Rauch, P., Gervais, M., Cranga, P., Baud, A., Hirsch, J.-F., Walter, A. and Beaumier, P. Blue EdgeTM: The design, development, and testing of a new blade concept, American Helicopter Society 67th Annual Forum Proceedings, 3-5 May 2011, Virginia Beach, Virginia, US.Google Scholar
18. Shinoda, P.M., Norman, T.R., Jacklin, S.A., Yeo, H., Bernhard, A.P.F. and Haber, A. Investigation of a full-scale wide chord blade rotor system in the NASA Ames 40- by 80-foot wind tunnel, American Helicopter Society 4th Decennial Specialist's Conference on Aeromechanics Proceedings, 21-23 January 2004, San Francisco, California, US.Google Scholar
19. Hodges, D.H. and Dowell, E.H. Nonlinear equations of motion for the elastic bending and torsion of twisted nonuniform rotor blades, NASA TN D-7818, December 1974.Google Scholar
20. Crews, S.T. and Hamilton, B.W. Army helicopter crew seat vibration – past performance, future requirements, Proceedings of the American Helicopter Society North East Region National Specialists’ Meeting on Helicopter Vibration, November 1981, Hartford, Connecticut, US.Google Scholar
21 Anonymous, Requirements for rotorcraft vibration, specifications, modeling and testing, Aeronautical Design Standard ADS-27A-SP, US Army Aviation Systems Command, Redstone Arsenal, May 2006, Huntsville, Alabama, US.Google Scholar
22. Norman, T.R., Shinoda, P., Peterson, R.L. and Datta, A. Full-scale wind tunnel test of the UH-60A airloads rotor, American Helicopter Society 67th Annual Forum Proceedings, 3-5 May 2011, Virginia Beach, Virginia, US.Google Scholar
23. Romander, E., Norman, T.R. and Chang, I.-C. Correlating CFD simulation with wind tunnel test for the full-Scale UH-60A airloads rotor, American Helicopter Society 67th Annual Forum, 3-5 May 2011, Virginia Beach, Virginia, US.Google Scholar
24. Yeo, H. and Romander, E.A. Loads correlation of a full-scale UH-60A airloads rotor in a wind tunnel, American Helicopter Society 68th Annual Forum Proceedings, 1-3 May 2012, Fort Worth, Texas, US.Google Scholar
25. Bousman, W.G. and Kufeld, R.M. UH-60A airloads catalog, NASA TM-2005-212827, August 2005.Google Scholar
26. Bhagwat, M.J. and Ormiston, R.A. Examination of rotor aerodynamics in steady and maneuvering flight using CFD and conventional methods, American Helicopter Society Specialist's Conference on Aeromechanics Proceedings, January 2008, San Francisco, California, US.Google Scholar
27. Yeo, H., Bousman, W.G. and Johnson, W. Performance analysis of a utility helicopter with standard and advanced rotors, American Helicopter Society Aerodynamics, Acoustics, and Test an Evaluation Technical Specialists Meeting Proceedings, January 2002, San Francisco, California, US.Google Scholar