Development of Interactive Aircraft Design Software for Use in Problem Based Learning

Abstract

In the last ten years or so, many interactive aircraft design software packages have been released into the market. One drawback of these packages is that they assume prior knowledge in the field of aircraft design. Also, their main purpose being the preliminary aircraft design in a commercial environment, and are not intended for instructional use. Aircraft Design is an iterative process, and the students in the formative years of training must realise that one year of study is not enough to embrace all the necessary underlying concepts in this field. Most universities present the aircraft design as a classical Problem-Based Learning scenario, where students work in groups, with the group size varying between 5 and 8 students., each with a designated role, to carry out a specific task. The students work through the classical process of preliminary design based largely on textbook methods. Therefore, the need for a preliminary design tool (software) that helps the students to understand, analyse, and evaluate their aircraft design process exists. The developed software does everything that is needed in the preliminary design environment. Students are interactively guided through the design process, in a manner that facilitates lifelong learning. Comprehensive output is provided to highlight the “what if scenarios”. The software consists of many modules such as input (user interface), weight estimation, flight performance, cost estimation, take-off analysis, parametric studies, optimisation, and dynamic stability. Due to the large number of input design variables, a full interactive Graphical-User-Interface (GUI) is developed to enable students to evaluate their designs quickly. Object-Oriented-Programming (OOP) is used to create the GUI environment. The stability and control derivatives computed in this work are largely based on analytical techniques. However, a facility is provided in the software to create the data input file required to run a software package produced by USAF, called DATCOM, that enables computation of the dynamic stability and control derivatives that can be ultimately used in flight simulation work. Amongst all the variables used in aircraft design, aircraft weight is the most significant. A new weight estimation module has been developed to increase the accuracy of estimation to better than 5%. Its output results agree very favourably with the published data of current commercial aircraft such as Airbus and Boeing. Also, a new formula is proposed to estimate the engine weight based on its thrust in the absence of the data available with high degree of accuracy. In order to evaluate the effectiveness of the design under consideration, a comprehensive methodology has been developed that can predict the aircraft price as a function of aircraft weight. The Direct Operating Cost (DOC) is also calculated using methods proposed by ATA, NASA, and AEA. Finally, a walk-through of two case studies are presented, one for large transport aircraft and other for small business jet, to show how typical undergraduate students will proceed with the design and to demonstrate the effectiveness of the developed software.