This paper investigates and compares the effect that the airframe configuration and installed engine have on the feasibility of a space plane. For this purpose, multi-disciplinary optimization of the aerodynamic shape and ascent flight path of the airframe was carried out assuming two types of airframe configurations, single stage to orbit (SSTO) and two stage to orbit (TSTO), and two types of propulsion systems, turbine-based combined-cycle (TBCC) and rocket-based combined-cycle (RBCC). The optimization calculation was performed using the stochastic process optimization technique (SPOT) that we have proposed. In this study, to reduce the computational load, the airframe weight and aerodynamic performance are estimated based on historical statistics. According to the results of the optimization, the TSTO configuration equipped with a RBCC engine had the highest feasibility. Sensitivity analysis was carried out for the time history of the angle of attack, and the structure of the characteristic solution space that reflects the airframe configuration and the installed engine was clarified. As a result, the importance of steering controls for each flight condition could be assessed.
In design method of open propellers, the distribution of circulation that gives the highest propulsive efficiency was obtained by Goldstein by satisfying the requirement of ``Betz's condition'' in late 1920s. On the other hand, any theoretical optimum design method of ducted fan has not been developed yet though the use of ducted fans by UAV, VTOL, etc., has increased in recent years. We developed the design method that gives the distribution of circulations with highest efficiency in the configuration of ``ducted propeller.'' The key point of this design method is that it is mathematically proven that the solution obtained by this method is the unique global optimum solution. In addition, the optimized blades here had wide tip chord as expected.
Punctuality gives an indication of delay from schedule on aircraft operation. Improvement of punctuality is one of the important topics for future ATM (Air Traffic Management) plans. To improve punctuality, it is indispensable to comprehend current state of delay. In this paper, delay analysis results from actual data of Japanese aircraft operation are presented. Firstly, punctuality on Japanese principal airports is studied. In addition, the punctuality is studied seasonally and weather impact on punctuality is briefly discussed. Moreover, aircraft operation is divided into the four phases to study delay in detail. Defining standard times, delay is computed for each phase. To spot the operation phases that incurred longer delay, the computed delays are compared.
For preventing debris-debris collision in orbit, it is very efficient to decrease on-orbit space debris itself. In case we find debris being about to collide against other debris, we must urgently remove it by removal satellites preliminarily stacked in orbit. This paper proposes initiative of zero-debris-collision area where the removal satellites can prevent all debris-debris collision, and reports the relation between the necessary number of the removal satellites and permissible period for their orbit transfer, by using minimum-fuel, multiple-impulse, and time-fixed solutions for coplanar circle-to-circle rendezvous, which indicates that we can defense the area of 500 to 1,500km in altitude by stacking 8 of the removal satellites at the altitude of 1,000km.
This paper reports flight controller design for In-Flight Simulator (IFS) MuPAL-α and some experiment results. As IFS MuPAL-α was required to realize handling characteristics of given models using only feedforward controllers, inverse systems were designed as the flight controller for model-matching control. Flight experiments confirmed that MuPAL-α with our controller has a research ability for handling quality investigation.