Skip to main content Accessibility help
  • Print publication year: 2013
  • Online publication date: May 2013

21 - Flight Dynamics


Handling qualities are defined as “those qualities or characteristics of an aircraft that govern the ease and precision with which a pilot is able to perform the tasks required in support of an aircraft role” (Cooper and Harper (1969)). Generally the terms “flying qualities” and “handling qualities” are interchangeable, although the titles of specifications more often refer to flying qualities. Handling qualities involve the aircraft, the pilot, the tasks, and the environment (Padfield (1998)). Most of this chapter deals only with the aircraft flight dynamics or stability and control characteristics: the equations and fundamental behavior of the rotorcraft rigid-body motion. Simplifications and approximations are made to focus on the fundamental behavior of the aircraft. A more rigorous approach is needed to obtain models sufficient for rotorcraft flight control system design. Padfield (2007) covers rotorcraft flight dynamics and handling qualities in depth.


Rotorcraft control requires the ability to produce moments and forces on the vehicle to establish equilibrium and thereby hold the aircraft in a desired trim state, and to produce accelerations and thereby change the aircraft velocity, position, and orientation. Like airplane control, rotorcraft control is accomplished primarily by producing moments about all three aircraft axes: pitch, roll, and yaw. The helicopter has in addition direct control over the vertical force on the aircraft, corresponding to its VTOL capability. This additional control variable is part of the versatility of the helicopter, but also makes the piloting task more difficult. The control task is eased by the use of a rotor speed governor to automatically manage the power.

Advisory Group for Aerospace Research and Development. “V/STOL Handling, Criteria and Discussion.” AGARD R-577-70, December 1970.
Amer, K.B.Some Flying-Qualities Studies of a Tandem Helicopter.” NACA RM L51H20a, October 1951.
Amer, K.B., and Tapscott, R.J.Studies of the Lateral-Directional Flying Qualities of a Tandem Helicopter in Forward Flight.” NACA Report 1207, 1954.
Blanken, C.L., Bivens, C.C., and Whalley, M.S.An Investigation of the Use of Bandwidth Criteria for Rotorcraft Handling-Qualities Specifications.” American Helicopter Society International Conference on Rotorcraft Basic Research, Research Triangle Park, NC, February 1985.
Blanken, C.L., Hoh, R.H., and Mitchell, D.G.Test Guide for ADS-33E-PRF.” American Helicopter Society 63th Annual Forum, Virginia Beach, VA, May 2007.
Cooper, G.E., and HarperRobert, P. Jr.The Use of Pilot Rating in the Evaluation of Aircraft Handling Qualities.” NASA TN D-5153, April 1969.
Crim, A.D., Reeder, J.P., and Whitten, J.B.Initial Results of Instrument-Flying Trials Conducted in a Single-Rotor Helicopter.” NACA Report 1137, 1953.
Gustafson, F.B., Amer, K.B., Haig, C.R., and Reeder, J.P.Longitudinal Flying Qualities of Several Single-Rotor Helicopters in Forward Flight.” NACA TN 1983, November 1949.
Gustafson, F.B., and Tapscott, R.J.Methods for Obtaining Desired Helicopter Stability Characteristics and Procedures for Stability Predictions.” NACA Report 1350, 1958.
Heffley, R.K.A Compilation and Analysis of Helicopter Handling Qualities Data.” NASA CR 3145, August 1979.
Hoh, R.H.Dynamic Requirements in the New Handling Qualities Specification for U.S. Military Rotorcraft.” Royal Aeronautical Society International Conference on Helicopter Handling Qualities and Control, London, UK, November 1988.
Hohenemser, K.Dynamic Stability of a Helicopter with Hinged Rotor Blades.” NACA TM 907, September 1939.
Hohenemser, K.H., and Yin, S.K.On the Use of First Order Rotor Dynamics in Multiblade Coordinates.” American Helicopter Society 30th Annual National Forum, Washington, DC, May 1974.
Hohenemser, K.H., and Yin, S.K.Methods Studies Toward Simplified Rotor-Body Dynamics.” NASA CR 137570, June 1974.
Johnson, R.L., and Hohenemser, K.H.On the Dynamics of Lifting Rotors with Thrust or Tilting Moment Feedback Controls.” Journal of the American Helicopter Society, 15:1 (January 1970).
Kaufman, L., and Peress, K.A Review of Methods for Predicting Helicopter Longitudinal Response.” Journal of the Aeronautical Sciences, 23:3 (March 1956).
Kelly, J.R., and Garren, J.F. Jr.Study of the Optimum Values of Several Parameters Affecting Longitudinal Handling Qualities of VTOL Aircraft.” NASA TN D-4624, July 1968.
Key, D.L.A New Handling Qualities Specification for U.S. Military Rotorcraft.” Royal Aeronautical Society International Conference on Helicopter Handling Qualities and Control, London, UK, November 1988.
Key, D.L., and Hoh, R.H.New Handling-Qualities Requirements and How They Can Be Met.” American Helicopter Society 43rd Annual Forum, St. Louis, MO, May 1987.
McIntyre, H.H.Longitudinal Dynamic Stability of a Helicopter with Torsionally Flexible Blades and Servo-Flap Control.” American Helicopter Society 18th Annual National Forum, Washington, DC, May 1962.
McRuer, D.T., and Krendel, E.S.Mathematical Models of Human Pilot Behavior.” AGARD AG-188, January 1974
Miller, R.H.Helicopter Control and Stability in Hovering Flight.” Journal of the Aeronautical Sciences, 15:8 (August 1948).
Miller, R.H.A Method for Improving the Inherent Stability and Control Characteristics of Helicopters.” Journal of the Aeronautical Sciences, 17:6 (June 1950).
Padfield, G.D.Controlling Tension Between Performance and Safety in Helicopter Operations. A Perspective on Flying Qualities.” Twenty-Fourth European Rotorcraft Forum, Marseilles, France, September 1998.
Padfield, G.D.Helicopter Flight Dynamics. Second Edition. Oxford: Blackwell Science Ltd, 2007.
Padfield, G.D.Rotorcraft Handling Qualities Engineering. Managing the Tension Between Safety and Performance.” American Helicopter Society 68th Annual Forum, Fort Worth, TX, May 2012.
Reeder, J.P., and Whitten, J.B.Some Effects of Varying the Damping in Pitch and Roll on the Flying Qualities of a Small Single-Rotor Helicopter.” NACA TN 2459, January 1952.
Reichert, G., and Huber, H.Influence of Elastic Coupling Effects on the Handling Qualities of a Hingeless Rotor Helicopter.” AGARD CP 121, September 1971.
Salmirs, S., and Tapscott, R.J.The Effects of Various Combinations of Damping and Control Power on Helicopter Handling Qualities During Both Instrument and Visual Flight.” NASA TN D-58, October 1959.
Simons, I.A., and Modha, A.N.Gyroscopic Feathering Moments and the “Bell Stabilizer Bar” on Helicopter Rotors.” Journal of the American Helicopter Society, 52:1 (January 2007).
Sissingh, G.J.Response Characteristics of the Gyro-Controlled Lockheed Rotor System.” Journal of the American Helicopter Society, 12:4 (October 1967).
Sissingh, G.J.Review and Discussion of ‘On the Dynamics of Lifting Rotors with Thrust or Tilting Moment Feedback Controls.”’ Journal of the American Helicopter Society, 15:1 (January 1970).
Stuart, J. III.The Helicopter Control Rotor.” Aeronautical Engineering Review, 7:8 (August 1948).
United States Army. “Handling Qualities Requirements for Military Rotorcraft.” Aeronautical Design Standard Performance Specification, ADS-33E-PRF, February 2000.
United States Government. “Requirements for Helicopter Flying Qualities.” Military Specification MIL-H-8501, November 1952.
United States Government. “General Requirements for Helicopter Flying and Ground Handling Qualities.” Military Specification MIL-H-8501A, September 1961.
United States Government. “Flying Qualities of Piloted V/STOL Aircraft.” Military Specification MIL-F-83300, December 1970.
United States Government. “Airworthiness Standards: Normal Category Rotorcraft.” CFR Title 14, Part 27, 2011.
United States Government. “Airworthiness Standards: Transport Category Rotorcraft.” CFR Title 14, Part 29, 2011.