2.6 Market Survey

the back, with an end cap on the top. The horizontal tail, shown as a T-tail set at the top of the vertical tail, consists of the stabilizer and the elevator. Canard configuration has ‘tail’ in front.

Nacelle Group

Podded nacelles are slung under the wings and one is mounted on the aft fuselage; pylons affect the attachment. Engines can be mounted on each side of the fuselage. The nacelle design is discussed in detail in Chapter 10. Turbofans are preferred for higher subsonic speed.

Undercarriage Group

The undercarriage, or landing gear, usually consists of a nose-wheel assembly and two sets of main wheels that form a tricycle configuration. Tail-dragging, bicycle, and even quad configurations are possible, depending on the application of an aircraft. Wheels are usually retracted in flight, and the retraction mechanism and stowage bay comprise part of the undercarriage group. Undercarriage design is discussed in Chapter 7.

Not shown in Figure 2.3 are the trimming surfaces used to reduce control forces experienced by the pilot. During the conceptual phase, these surfaces generally are shown schematically, with size based on past experience. The sizing of trim surfaces is more appropriate once the aircraft configuration is frozen (i.e., a Phase 2 activity). Trim-surface sizing is accomplished by using semi-empirical relations and is fine-tuned by tailoring the surfaces and areas or adjusting the mechanism during flight trials. In this book, trim surfaces are treated schematically – the main task is to size the aircraft and finalize the configuration in Phase 1. On larger aircraft, powered controls are used; pitch trimmings in conjunction with moving tail planes. A propeller-driven aircraft is preferred for cruise speeds below Mach 0.5.

2.5.2 Military Aircraft and Its Component Configurations

This extended section of the book can be found on the Web at www.cambridge

.org/Kundu and depicts typical military aircraft components, with Figure 2.4 depicting an exploded view of an F16-type aircraft configuration.

Figure 2.4. Military aircraft configuration

Figure 2.5. A diagram of the General Dynamics (now Boeing) F16

2.6 Market Survey

In a free market economy, an industry cannot survive unless it grows; in a civilmarket economy, governmental sustenance is only a temporary relief. The starting point to initiate a new aircraft design project is to establish the key drivers – that is, the requirements and objectives based on market, technical, certification, and organizational requirements. These key drivers are systematically analyzed and then documented by aircraft manufacturers (Chart 2.6).

In several volumes, documents that describe details of the next tier of design specifications (i.e., requirements) are issued to those organizations involved with

The Final Design

Chart 2.6. The design drivers (in a free market economy, it faces competition)

a project. A market survey is one way to determine customer requirements – that is, user feedback guides the product. In parallel, the manufacturers incorporate the latest but proven technologies to improve design and stay ahead of the competition, always restricted by the financial viability of what the market can afford. Continual dialogue among manufacturers and operators results in the best design.

Military aircraft product development has a similar approach but requires modifications to Chart 2.6. Here, government is both the single customer and the regulatory body; therefore, competition is only among the bidding manufacturers. The market is replaced by the operational requirements arising from perceived threats from potential adversaries. Column 1 of Chart 2.6 becomes “operational drivers” that includes weapons management, counterintelligence, and so on. Hence, this section on the market survey is divided into civilian and military customers, as shown in Chart 2.7. Customer is a broad term that is defined in this book as given in the chart.

In the U.K. military, the Ministry of Defense (MoD), as the single customer, searches for a product and circulates a Request for Proposal (RFP) to the national infrastructure, where most manufacturing is run privately. It is similar in the United States using different terminology. The product search is a complex process – the MoD must know a potential adversary’s existing and future capabilities and administrate national research, design, and development (RD&D) infrastructures to be ready with discoveries and innovations to supersede an adversary’s capabilities.

Customer of Aircraft

Chart 2.7. Customers of aircraft manufacturer