An Optimal Control Approach for Harmonizing Tilt-Wing Design and Operations

Abstract Tilt-wing aircraft combine vertical take-off and landing capability with efficient cruise flight, offering high operational flexibility for Advanced Air Mobility (AAM) applications. The transition between hover and forward flight relies on aero-propulsive interaction through propeller slipstream. While the accelerated transition from hover to cruise benefits from increased slipstream-induced velocities, decelerating and descending transition flight is constrained, particularly when flow separation must be avoided. This paper quantifies these constraints for a tandem tilt-wing configuration and examines their implications for vehicle design and operation. The analysis combines analytical considerations, steady trim calculations, and optimal-control–based trajectory optimization. Results show that the backward transition requires significant upward motion to maintain attached flow, leading to substantial altitude gains that complicate terminal-area procedures and increase energy demand. To improve operational compatibility, a multiphase strategy is proposed that combines a steep glide segment with a subsequent climbing transition maneuver. In addition, potential design modifications are investigated. Although these measures can improve transition characteristics, they generally conflict with hover and cruise efficiency and increase system complexity. The proposed optimal-control framework therefore provides a quantitative basis for harmonizing aircraft design and operational procedures under high-incidence transition constraints, supporting the safe and efficient integration of tilt-wing into AAM traffic systems.