Exploratory evaluation of side-stick flight sciences on variable stability research aircraft: a study of inceptor throw and force gradient

Abstract

There is increasing evidence of the benefits of active side-stick inceptors in rotorcraft in areas such as pilot comfort, handling qualities, safety, limit protection, and cockpit design. In-flight evaluations of an active force-sensing (large-displacement, position-output) side-stick inceptor were conducted on the NRC Bell 412 Advanced Systems Research Aircraft. The aircraft was configured with a Rate Damped control response type in pitch and roll axes. A number of qualitative and quantitative results due to side-stick setting preferences were gathered. For a survey of modified ADS-33E-PRF Depart-Abort and Lateral-Reposition mission task elements in good cueing conditions, static setting preferences included average longitudinal and lateral force-gradients of 0.43 N/mm and 0.32 N/mm, respectively. The associated longitudinal and lateral throw limits were 19.3 mm and 25.8 mm, respectively. Dynamic setting preferences included maximum longitudinal and lateral natural frequencies of 16 rad/sec and 15 rad/sec, respectively, combined with average damping ratios of 0.65. In a high bandwidth variable stability helicopter application, this study exposed both benefits (rapid tailoring, comfort) and limiting conditions (physical static and dynamic constraints) of active side-stick technology.