Aircraft Design最新文献

New analytic expressions, based on the exact performance relationships without making the approximations on which the classical Breguet equation is based, are developed to predict cruising range and endurance of turboprop, turbofan, or piston–propeller aircraft at constant speed and altitude. Also, the optimal cruising speed to achieve maximum range is determined.

A novel method has been developed for calculating gradients of aerodynamic force and moment coefficients for an aeroelastic aircraft model. This method is intended for use in preliminary-level aircraft design which typically involves computationally expensive aerodynamic and structural analyses. This method uses the global sensitivity equations (GSE) to express the aero-structural coupling in an aircraft model. In addition, a reduced-order modal analysis approach is employed to condense the coupling bandwidth between the aerodynamic and structural models. Coarse-grained parallel computing is applied to reduce the wall-clock computational time of the expensive aerodynamic analysis needed in this sensitivity analysis method. A supersonic transport aircraft model is examined in this study, subject to Mach 2.4 cruise flight conditions. Aerodynamic analysis is performed using a NASA-developed Euler/Navier-Stokes solver, and structural analysis is performed using commercial finite element analysis software. The GSE/modal analysis method is used to compute the sensitivity of the aerodynamic performance of the aircraft subject to perturbations in the angle-of-attack, wing sweep angle, and wing thickness. Good agreement is obtained between gradients computed with the GSE/modal analysis approach and the same quantities computed using a traditional, computationally expensive, finite difference approach. A cost analysis demonstrates that the GSE/modal analysis method is more computationally efficient than the traditional approach if gradients are needed for two or more aircraft design parameters.

Aluminum wing, empennage and fuselage structural weights are functions of wing loading in commercial and general aviation applications. Component weight data for 61 airplanes were used to develop three relationships: wing weight/reference area as a function of wing loading, empennage weight/reference area as a function of wing loading, and fuselage weight/surface area as a function of wing loading. These relationships can be used for quick estimation of wing, empennage and fuselage weights or checking the reasonability of estimates obtained through other methods. It should be possible to develop similar relationships for military aircraft, though the addition of thrust loading to the functionality may be needed to account for variances in the structural design load factor.

This paper discusses the application of simulated annealing in the conceptual design and optimization of twin-turboprop Commuter & Regional aircraft to obtain the optimum configuration and flight profile of such aircraft for operation over a given stage length. Generalized cost of travel incurred by a passenger for air travel between two cities is considered as the objective function to be minimized. Generalized cost is assumed to consist of four cost terms, viz., access cost, flight cost, time cost and airport cost. A computational methodology was developed for the estimation of these cost terms for short-haul air travel, as a function of 17 design variables and nine constraints. A simulated annealing optimization method was coupled to this methodology and a case study for short-haul business travel in India was carried out. A modified optimization strategy was adopted to reduce the overall computation time required. The results obtained in this case study are discussed in the paper.

This paper describes the wind tunnel testing of a specially designed aircraft model allowing systematic variation of geometric parameters related to overall aircraft configurations. The experiment work was carried out in the 1.8 m low-speed wind tunnel at VZLU, Aeronautical Research and Test Institute in Prague. The resultant data created an aerodynamic database for numerical modelling and verification. In addition, numerical validation of CFD package FLUENT was performed in the computerised fluid dynamic laboratory at the Department of Aerospace Engineering, University of Glasgow as a part of the ongoing research collaboration between both institutions. The wind-tunnel test program had two aims

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  to provide basic aerodynamic data effects of multi-surface aircraft configurations with a view to assessing the degree to which specific design features such as a combination of canard, wing and tail plane are beneficial to aircraft aerodynamic performance

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  to provide an aerodynamic database for numerical validation.

In this paper a conceptual design methodology for launch vehicles which makes use of a finite element-based structural analysis is developed. The proposed methodology is then tested by applying it to the conceptual design of single stage to orbit (SSTO), vertical take-off and horizontal landing (VTHL), rocket engines powered reusable launch vehicles (RLVs), like Venture Star.

Besides the conceptual configuration development of an aircraft, a modern design tool should cover the evaluation of competitor aircraft, allow the assessment of technological and operational scenarios, and thus should have the potential to `right first time design'. For that purpose, the design system VisualCAPDA was developed on the basis of the former CAPDA system by evolutionarily introducing modern software standards under the premise of maximum reusability of existing FORTRAN coded methods. The new system plays the role of a workbench, which has to provide the analysis methods and necessary data. Through a graphical user interface the application of the system comes along as comfortable for the user as possible. In order to cover also turboprop aircraft, new modules with respect to cabin layout, propeller aerodynamic and acoustic analysis, propeller slip stream, engine modeling, geometry modeling are integrated into the design tool. The flexibility of the new system is demonstrated by applying it to the configurational development of propeller aircraft, investigating actual problems such as `Twin or Quad', `Turboprop or Turbofan', and finally, dealing with typical optimization problems.

The present paper describes the major features of an unmanned air vehicle, designed under very severe safety and performance requirements for missions of surveillance of borders and coasts, fire detection, and search and rescue. Because of safety reasons, two engines are mandatory for the aircraft. Additionally, the mission requirements can be translated into initial specifications in the following terms: payload not less than 42 kg, cruise speed between 120 and 150 km/h, maximum speed higher than 200 km/h, cruise altitude of 3000 m, service ceiling higher than 4000 m, autonomy around 15 h, gliding distance covered after full engine failure greater than 100 km, and conventional take-off and landing in short unprepared runways. The design covers all common areas: configuration and sizing, aerodynamics, performance, stability and control, airworthiness, and initial structural design. Following suggestions from scholars and authorities, and taking into account the peculiar operational conditions of the vehicle, JAR 22 (Powered sailplanes, Utility category) are used as the basis for airworthiness certification.