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Practical control law design for aircraft using multivariable techniques
Published in Mark B. Tischler, Advances in Aircraft Flight Control, 2018
James D. Blight, R. Lane Dailey, Dagfinn Gangsaas
Traditionally, transport airplanes have been designed to have a certain level of inherent longitudinal stability. This and other control requirements dictate the size of the horizontal tail and restrict the permissible aftmost location of the centre of gravity (c.g.). The efficiency of these airplanes can be improved by decreasing the horizontal tail size and moving the c.g. aft. The corresponding reductions in weight and trim drag from the decreased tail size and trim load on the tail can yield a significant reduction in fuel consumption (Boeing 1980). However, these airplanes will have unsatisfactory longitudinal stability and control characteristics within part of their c.g. and flight envelopes.
Numerical investigation on the hydrodynamic performance of high-speed planing hull with transom interceptor
Published in Ships and Offshore Structures, 2020
J. Suneela, P. Krishnankutty, V. Anantha Subramanian
Application of numerical modelling in ship hydrodynamics gives stable solutions in the case of resistance and flow evaluation at a steady speed. Simulations are performed using RANSE-based CFD software used in this study. RANSE solver is used for simulating the dynamic changes in trim, drag and bottom pressure of the hull with and without the interceptor on the planing hull at various beam Froude numbers. The obtained numerical results are validated against experimental measurements conducted in the towing tank, IITM. In addition to the resistance and trim effects, kinematics and dynamics of high-speed planing hull with and without the interceptor are also presented. Besides running trim and resistance the kinematic aspects of flow including free surface wave pattern and pressure distribution under the hull are simulated. Figure 2(a) displays the CAD model used for the study with the interceptor fitted to the transom of the planing hull. Figure 2(b) shows the geometric variables of hull with an interceptor height, h = 25 mm in prototype and deadrise angle, β = 20 degrees.