As air traffic systems transition towards trajectory-based operations with fewer constraints on flight planning, optimizing trajectories in flight plan generation holds promise for greater efficiency. To harness this potential, the optimizer necessitates an aircraft performance model with highly accurate fuel flow rate predictions, capable of accounting for individual aircraft performance variations over time due to daily wear-and-tear of flight operations and maintenance. This study proposes a method to construct tailored performance models using airline-acquired flight data. We demonstrate the feasibility of simultaneously estimating aerodynamic and fuel models, traditionally regarded as challenging, by incorporating vertical velocity due to climb and descent, and inertial drag due to acceleration and deceleration. This approach reduces estimation bias, enhancing the model’s applicability across a wider flight envelope including climb and descent phases, thus facilitating more comprehensive trajectory optimization solutions. Hold-out validation confirms the model’s accuracy, with mean fuel flow rate error below 1%. Furthermore, this method’s ability to extract individual aircraft performance from flight data suggests potential applications in maintenance-related performance monitoring.

A novel airspeed detection method was developed for electrified aircraft, offering a reliable alternative to conventional air data equipment (ADE) utilizing pitot tubes. Conventional ADE systems are susceptible to failure and may pose challenges in installation on newly configured aircraft. The proposed method used monitored quantities such as rotational speed, motor torque, and current of a propulsion propeller positioned directly opposite to the airflow. The procedure for calculating propeller torque and the subsequent detection of airspeed by propeller advance ratio were formulated using the monitored quantities. Since it is inherently difficult to determine a priori the propeller characteristics, particularly the relationship between propeller torque and advance ratio, a ground-roll-based procedure was devised to identify these characteristics. Additionally, an advanced procedure was developed to estimate airspeed as well as air density by modulating rotation speed marginally during flight. Flight demonstrations employing an electrified motor glider showed minimal deviation between this method and ADE outputs, typically within a few percent. Wind tunnel tests employing the same propeller as the motor glider demonstrated that airspeed and density can be estimated within 10% error.

This study proposed and evaluated a cooling system that uses liquid film evaporation for high heat flux environments on a heated rotating disk, such as the axial gap motor (AGM) used in liquid rocket engines. Cooling conditions to avoid demagnetization of the rotor were evaluated through heat conduction simulations of the rotor, and the liquid film thickness required to achieve sufficient cooling power was investigated. Furthermore, the effects of different coolants on cooling power were investigated. The results showed that the required heat transfer coefficient depended on the coolant, and a liquid film with a thickness of a few micrometers was required for effectively cooling AGMs in rocket engines. Additionally, depending on the heat generation rate, even evaporative cooling may fail to easily cool AGMs in rocket engines. Therefore, technologies to reduce the heat generation rate in the motor are required.

Beams consisting of lattice structure with slits for high-accuracy deployable reflectors were developed, and their mechanical characteristics were evaluated through numerical simulations and experiments. In these lattice beams with slits, slit members are placed on the side of the lattice beam where bending deformation is to be restrained. When the beam bends above a predetermined level, the slits close, and the members contact each other, thereby increasing the stiffness of the beam structure and restraining deformation from the predetermined shape. The numerical analyses were conducted by changing the stiffness of the beam material, and it was confirmed that the proposed lattice beam with slits can reduce the sensitivity of the deformation to changes in the stiffness of the beams. Then the model was printed using a 3D printer, and bending experiment was carried. The experimental result shows that the appropriately designed beam structure can be easily bent at low loads up to a designed deformation, and their stiffness increases after the slits are closed. This result indicates that beams for deployable reflectors consisting of these lattice structures deploy easily, and the deformation due to disturbance can be mitigated by increasing the structure’s stiffness after deployment.