08.06.2012, 68th Annual Forum of the American Helicopter Society, Fort Worth, USA (April 30-May 3, 2012)

Gareth Padfield, now Professor Emeritus at the University of Liverpool, was awarded the prestigious Nikolsky Lecture for his outstanding merits in the field of helicopter handling qualities. Among these merits, his essential contribution in assembling the ARISTOTEL consortium and setting the agenda for the project deserves mention.

Marilena Pavel, from the Technical University of Delft, the Netherlands, and coordinator of the project, illustrated the goals and the current status of ARISTOTEL in a presentation entitled “A Retrospective Survey of Adverse Rotorcraft Pilot Couplings in European Perspective”. The paper was a synthesis of some initial ARISTOTELian investigations in the area of RPCs. After presenting an overview of past, present and future RPCs, the paper concentrated mainly on the first campaign of biodynamical tests performed in the project. The results showed that biodynamic feedthrough (BDFT) problems depend not only on more obvious features such as pilot weight and posture but also on more elusive factors such as pilot workload and task. The greatest pilot handling qualities rating worsening due to biodynamic interaction between the pilot and the elastic accelerations corresponded to a central stick system.

Michael Jones, from the University of Liverpool, UK, presented a work entitled “Generic Research Simulator Requirements for Prediction of Adverse Rotorcraft Pilot Couplings in the Heave Axis”. This paper presented the results of a preliminary study into the difference in PIO proneness of a helicopter simulation model when the motion, force-feel and visual cues in the facility are varied. The presentation concentrated on the motion cueing aspect of the work. Here, it was found that the use of motion will increase the incidence of PIO events but that, paradoxically, once a PIO is in progress, the absence of motion will tend to make the event more severe. Questions raised were, unsurprisingly, centred on motion cueing issues. Specifically questions were raised on the means used to quantify the ‘level of motion’ employed and the reason for concentrating on Category I PIOs.

Pierangelo Masarati, from Politecnico di Milano, Italy, presented the work “Theoretical and Experimental Investigation of Aeroelastic Rotorcraft-Pilot Coupling”, where he discussed the results of an experimental campaign performed in cooperation with the University of Liverpool which consisted of the triggering of aeroelastic instabilities in the HELIFLIGHT flight simulator using a simple helicopter model restricted to the heave axis in hover. In another work, “Robust Stability Analysis: a Tool to Assess the Impact of Biodynamic Feedthrough on Rotorcraft”, in cooperation with the Technical University of Delft and the Max Plank Institute of Tübingen, Germany, he explained how to study the coupled stability of rotorcraft and pilot by matching the stability margins of vehicle models with the experimentally measured Biodynamic Feedthrough (BDFT) of the pilot. Based on the questions that followed the presentation, the audience appreciated the fact that this project is both raising awareness of and addressing these kinds of problem. Interesting comments came from outstanding personalities like Dr. Robert Ormistron (US Army), Dr. Thomas Parham (BHTI), and Dr. Daniel Alvarez (STI).

Download Presentations:

• Generic Research Simulator Requirements for Prediction of Adverse Rotorcraft Pilot Couplings in the Heave Axis (pdf)
• Theoretical and Experimental Investigation of Aeroelastic Rotorcraft Pilot Coupling (pdf)
• Robust Stability Analysis a Tool to Assess the Impact of Biodynamic Feedthrough on Rotorcraft (pdf)