| Abstract | Wake vortex encounters, occurring in air transport operations, involve substantial loads, which can result in aggravated flight-path upsets. In order to explore flight control system design for alleviation, the alleviatory effects of conventional flight control surface deflections, upon wake vortex encounter loads has been examined. For this, data was gathered during NRC T33 wake turbulence flight research, of Heavy and Super Category jet transports engaged in enroute operations. Comparative data consists of stick-fixed wake vortex encounters and manually-applied alleviatory control inputs to conventional flight control surfaces. For the alleviatory control-input case, the inputs are experience-based, fully-learned, in other words categorised as instinctive. As such, they were of a high frequency-band, for manual control inputs. Thus, they represent a close-to-limit ability to alleviate wake vortex encounter loads, for the T33 with manual control inputs. The reduction in loads between the two cases, stick-fixed and stick-alleviatory was of the order of 50-60%. Given the greater bandwidth of digital flight control systems, it is reasonable to speculate that a wake vortex loads alleviation of significantly greater than 50% could be possible with a digital flight control system, based upon the appropriate flight control laws. |
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