Miscellaneous Design Considerations

15.1 Overview

Although the main tasks of the aircraft configuration are now completed, there are other topics of interest that require understanding of design. This chapter is an overview of the impact made by technological advances that must be considered at the conceptual stages to arrive at a “satisfying” design. It offers an understanding of specialized topics, some of which may appear out of context during the concep­tual phase, but they do contribute to aircraft design. The aircraft external geometry is not affected by these considerations (unless a radical approach is taken); how­ever, there could be weight and cost changes. The semi-empirical weight equations in Chapter 8 are sufficient and can be modified with improved data. In the industry, a more accurate weight estimation is required to reflect the changes affected by the topics discussed in this chapter.

A detailed study is beyond the scope of this book. Most academic institutions offer separate courses on some of the topics, such as aircraft structure, associated materials, and aircraft systems. Some of these topics sometimes escape attention because the undergraduate curriculum is already full with the main aeronautical subjects. Conceptual aircraft design is not only producing a geometry capable of meeting performance specifications; it also involves early thinking about environ­mental issues, safety issues, materials and structures, human interface with the flight deck, systems considerations, and military survivability issues that affect aircraft weight and cost. Therefore, whereas there is nothing to be altered on the final­ized and substantiated configuration thus far obtained, it is beneficial for readers to appreciate the role of these varied topics. Some of the emerging scenarios are new and have yet to be implemented. It is important that newly initiated readers have a sense for what is required by these topics, which may be developed during a second term of coursework.

Environmental and safety issues must comply with standards specified by the FAA (United States), the EASA (Europe), and the ICAO (international). The dif­ferences among the agencies are minor. Military aircraft requirements are governed by MILSPECS/DEF standards. Aircraft doors (including emergency types) and environment standards, regulated by the FAA and the ICAO, also are described in this chapter.

The topics concerning military aircraft design are complex issues and must be studied separately (refer to specialized textbooks). Previous chapters clearly indi­cate the complexity of military aircraft design, which makes advanced military – aircraft design more difficult for undergraduate students.

Future designs indicate changes in aircraft configurations that are currently undergoing research and development (e. g., the BWB; see Figure 15.10). The basics of the current type of aircraft design must be understood before advanced designs can be undertaken.

15.1.1 What Is to Be Learned?

This chapter covers the following topics:

Introduction to the topics discussed How noise emissions affect design Engine exhaust emissions Aircraft material selection Laying out internal structural arrangements Civil aircraft doors and emergency egress Aircraft flight deck (i. e., cockpit) layout Aircraft systems

Military aircraft survivability and stealth issues Emerging scenarios

15.1.2 Coursework Content

The coursework exercises pertain only to Section 15.7 in which readers verify the Bizjet emergency-door compliance with regulatory requirements. Also, the course – work discusses the choice of materials in Section 15.5. Otherwise, there is no other coursework unless a second term explores these topics. Readers may obtain equip­ment sales brochures supplied by various manufacturers in which dimensions and weights are listed; the Internet is also a good source of information.

15.2 Introduction

The following topics are chosen deliberately to broaden the design perspective of readers. Some are of relatively recent origin, gradually evolving since the 1970s:

• environmental issues (i. e., noise and engine emissions and end-of-life re­cycling)

• materials and structures (i. e., the advent of new materials impacting design)

• safety issues (e. g., emergency exits and chutes)

• human interface (i. e., flight-deck description and displays)

• system-architecture issues (e. g., avionics, electrical, and mechanical systems)

• military aircraft survivability issues (e. g., stealth and ejection)

• emerging scenarios (e. g., terrorism and health protection)

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