15.2 Introduction

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 militaryaircraft 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:

Section 15.2: Introduction to the topics discussed

Section 15.3: How noise emissions affect design

Section 15.4: Engine exhaust emissions

Section 15.5: Aircraft material selection

Section 15.6: Laying out internal structural arrangements

Section 15.7: Civil aircraft doors and emergency egress

Section 15.8: Aircraft flight deck (i.e., cockpit) layout

Section 15.9: Aircraft systems

Section 15.10: Military aircraft survivability and stealth issues

Section 15.11: 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 coursework 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)

15.2.1 Environmental Issues

Since the advent of large commercial jets in the 1960s (e.g., the B707, DC8, Convair 990, and VC10), the noise profile has become an isssue for residents living in an airport vicinity. Litigation cases began to increase as a result of damages to property and health. First, the FAA and then the ICAO became involved in order to limit noise levels in a prescribed manner. Aircraft and engine designers strove to reduce or suppress noise during takeoffs and landings. Research is developing ways to reduce noise resulting from supersonic shock waves, also known as booms. Currently, there are no civil aircraft operating at supersonic speed – the Concorde was removed from service after a long operational period – partly on account of economic reasons. Supersonic aircraft are not addressed in this book; nevertheless, they fly subsonic during takeoffs and landings. References [1] through [3] may be consulted for more details on supersonic aircraft.

In the 1980s, concerns were raised on climate change to which engine emissions contribute. Again, regulatory agencies intervened to set achievable standards in order to limit pollution caused by engine exhaust gases.

The disposal of life-expired, grounded aircraft must be considered in an early design phase.

15.2.2 Materials and Structures

The choice of materials and the internal structural arrangement affect aircraft weight and cost. Materials used in the B787 made the aircraft lighter – it was a success with numerous sales even before its first flight. This demonstrates the importance of selecting appropriate materials during the conceptual design phase. The IPPD environment is a good forum in which to make choices.

15.2.3 Safety Issues

With increased passenger capacity, a quick egress is required by the regulatory agencies to ensure safety in the rare event of a fire hazard on the ground or a postcrash evacuation. The regulatory requirements stipulate a minimum number of exit doors (i.e., both main and emergency) and slides and chutes that ensure egress within a specified time. For military aircraft, the extreme measure of ejection is incorporated into design.

15.2.4 Human Interface

With an increased demand in a pilot’s workload, it is important to understand the aircraft flight deck (i.e., cockpit) and the arrangement of systems. Readers must be aware of the nature of design features for the human-interface aspect, which can affect the aircraft weight, cost, and shape of the forward-fuselage–canopy area.

15.2.5 Systems Architecture

Aircraft subsystems consist of avionic, electrical, mechanical, hydraulic, and pneumatic systems. The extent of an aircraft’s weight and cost depends on the subsystem