# Glider and Airplane Design

11.1 Introduction

This chapter deals with simple aspects of airplane design and stability analysis which have been motivated by one of the authors (JJC) participation over the last 15years, as faculty advisor of a team of undergraduate students, in the Society of Automotive Engineering (SAE) Aero-Design West competition. This is a heavy lifter competition. Each year SAE publishes new rules for the competition, enticing students to design a different airplane. In the “regular class”, the power plant and engine fuel are imposed and the airplane must take-off within a 200 ft runway. Some other constraints change from year to year, such as maximum wing span, or maximum lifting surfaces area, etc. In the “advanced class”, the engine displacement is specified, but the engine make and fuel are the team’s choice. A take-off distance is either imposed or targeted with a flight raw score depending heavily on how close to 200 ft take-off occurs. A round counts when the airplane lands within a 400 ft marked area of the runway without having lost any part. Then, the payload is removed from the payload bay and is weighted to attribute points to the flight. During these years, basic prediction tools were developed to help students design and predict their airplane performance. They consist of three simple computer models, a rapid prototyping code, a ground acceleration code and a flight equilibrium code. Furthermore, each year, the SAE competition has served as an on-going project in the applied aerodynamics class, culminating in a design project, as last assignment for the quarter, that adheres to the SAE rules of that year. This was a source of motivation for the students as many of the team members of the Advanced Modeling Aeronautics Team (AMAT) are taking the class. Since 2006, a double element wing was used, which attracted a lot of interest and proved to produce a very high lift. This chapter describes the various models implemented, with a view to helping students with design and estimation of airplane performance. First, the aerodynamic model of a classical configuration is developed, with the main wing in the front and the tail behind it. This is an easier model to study than the “canard” configuration in which small lifting surfaces are placed near the front of the fuselage and the main wing is moved further back, due to the more complex interaction of the canard on the main wing.