The aerodynamic characteristics of the rotors and wing with the distance between rotors d/2R and the distance between rotors and wing z/R of a winged tandem rotor with the cyclic pitch control of the rotor and the pitching, rolling, and torque balance of the rotors were investigated using rFlow3D which is a CFD code on hover. Results showed that the lateral cyclic pitch eliminated the head-up moment of the front rotor caused by the overlap, but increased the rotor efficiency loss and the induced power overlap factor for d/2R ≧ 0.5. Compared to tandem rotors, winged tandem rotors of z/R = 0.2 increased the rotor-induced power by up to 27% because the rotor thrust increased to balance the wing download. The wing download was about 18% of the rotor thrust for d/2R ≦ 0.5. The local wing download increased due to the downwash caused by the interference of the blade tip vortices of the front and rear rotors. As the z/R of the winged tandem rotor increased, the rotor-induced power increased, and the wing download to rotor thrust ratio decreased.

The pre-cooled turbojet (PCTJ) engine has been studied in the Japan Aerospace Exploration Agency (JAXA). Although conventional jet engines operate under fuel lean conditions, the PCTJ engine is designed to operate with an equivalence ratio beyond 2 in the afterburner. The jet noise intensity can increase with increasing the equivalence ratio due to the increase in the exhaust velocity. Combustion instabilities have also been a major concern in terms of acoustic radiation under rich conditions, which involve intensive pressure oscillations resulting in combustion noise. In this study, effects of equivalence ratio on the acoustic characteristics of the afterburner are investigated using a high enthalpy wind tunnel. As a result, combustion noise is observed at lean and rich equivalence ratios but has a little contribution to the overall acoustic radiation. Regarding the jet noise, the sound intensity is almost the same regardless of the equivalence ratio since the convective velocity does not change so much.

Range of Passenger Transport Jet Airplanes were estimated by the Breguet equation and estimated results were compared with payload/range charts in airport planning manuals and fairly agreed with them. Although it is often mentioned that the Breguet equation is for propeller driven airplanes, in case that the efficiency of turbofan engine can be presumed constant, the Breguet equation is applicable to jet airplanes and some of Boeing and Airbus information support this assumption. This method is so useful that aircraft aerodynamic performance is represented solely by L/D and it becomes easy to see how airplane dimension such as wing span or wetted area influence $L/D$, that is range performance.

This paper examines a method for approximating the minimum-time attitude maneuvers of spacecraft with flexible structures. For an attitude maneuver around a single axis, we considered a scenario in which a symmetric step-like torque input is applied with respect to the half-maneuver time. We propose a method for determining an input that achieves attitude change in nearly the minimum time. This input ensures that the spacecraft's angular velocity as well as the mode coordinates of the structural vibrations and their time derivatives reach zero at the final time. In addition, we propose a method to extend the robustness of the input to uncertainties in the frequency and damping ratio of vibration modes. Simulations of the proposed method were conducted using a spacecraft model. The results demonstrate that the spacecraft can change its attitude without any residual vibrations under the condition of no modeling errors and exhibit robustness against uncertainties in the vibration frequency and damping ratio.