Preliminary Sizing of FAR Part 23 and Part 25 Aircraft

Autor: Joeri Heinemann

Datum: 12.07.2012

Master Thesis


This thesis covers the subject of preliminary sizing together with the development of the SAS Optimizations tool for Part 23 and Part 25 certification requirements. Preliminiary sizing is a very important step in the process of designing an airplane as it decides if the airplane will be further developed or not. The design of an airplane is defined by different specifications and requirements that can follow from a mission specification or market research, etc. The goal of preiminary sizing is translating these requirements and specifications into design and performance parameters. Most of these requirements and specifications are defined by certification requirements. Therefore Part 23, Part 25 and CS-VLA have been analysed to see which requirements affect the design. In order to translate these requirements and specifications to performance parameters, the mechanics behind each flight phase have to be analysed. With these equations resulting from these mechanics, a tool is developed that allows students to perform preliminary sizing by use of a set of input parameters and then perform an optimization on this design for a chosen design goal. In order to build the tool for Part 25, OPerA was dismantled and deconstructed to a more simple version that could perform the optimization by using the algorithms used in OPerA. After this a more detailed Oswald Factor calculation was implemented. This tool could now be used to build a tool for Part 23 as well by making the necessary changes according to the certification requirements. With the tool finished, it was decided to write a general users guide to SAS Optimization.