Commercial Airplane Design Principles

Pasquale M. Sforza

• Publisher: Butterworth-Heinemann
• Year: 2014
• ISBN:
  9780124199774
• Topic: Technology & Engineering
• Subtopic: Aeronautic & Astronautic Engineering
• Index: Technology & Engineering

Commercial Airplane Design Principles is a succinct, focused text covering all the information required at the preliminary stage of aircraft design: initial sizing and weight estimation, fuselage design, engine selection, aerodynamic analysis, stability and control, drag estimation, performance analysis, and economic analysis.

The text places emphasis on making informed choices from an array of competing options, and developing the confidence to do so.

• Shows the use of standard, empirical, and classical methods in support of the design process
• Explains the preparation of a professional quality design report
• Provides a sample outline of a design report
• Can be used in conjunction with Sforza, Manned Spacecraft Design Principles to form a complete course in Aircraft/Spacecraft Design

Chapter 1

Market Survey and Mission Specification

Abstract

An introduction to the commercial airplane market and its prospects for growth over the next 20 years is presented in terms of numbers of new deliveries and the associated market value. The size and make-up of the fleet and the geographical distribution of the market value of purchases is discussed. Technology drivers such as fuel efficiency, weight reduction, drag reduction, engine design, carbon footprint, biofuels, alternative fuels and power sources, and noise and vibration are described, along with brief comments on cargo aircraft. A summary of the actions necessary to initiate a design project for a proposed commercial airplane including the development of a detailed mission specification and a market survey is presented.

Keywords

Commercial aircraft markets; Fuel efficiency; Drag reduction; Noise; Carbon footprint; Biofuels; Design project

1.1 A growing market for commercial aircraft

The fleet of commercial aircraft is aging and new market pressures portend a large and growing market for new aircraft. Approximate average ages of the fleets of representative US and international airlines as of the end of 2011, according to Airfleets (2012), are shown in Figure 1.1.

Figure 1.1 Size and average age of the fleets of US international airlines as reported by Airfleets (2012).

The escalation of fuel prices, increased concern over environmental effects, and changes in the nature of airline services to passengers are pushing airline operators into renewing their fleets. Manufacturers are therefore putting intense efforts into designing and producing aircraft that will provide superior economic and environmental performance. Sales of US commercial aircraft rose from a low point in 2003 up to a fairly constant value starting in 2007, as can be seen in Figure 1.2, as reported by the Aerospace Industries Association (2012).

Figure 1.2 Annual sales of US civil aircraft over the period 2001–2012 as reported by the Aerospace Industries Association (2012). The numbers for 2012 are estimates. The deflator used by the AIA assumes 2000 as the base year.

Airbus has had some setbacks, in both the new A380 and the developing A350, and now has somewhat more than 40% of market share, a figure that is often taken as an indicator of serious competition. The Airbus figures owe a great deal to the continued success of the narrow-body A320. However, in the wide-body field it is losing out to Boeing, whose 777, 747-8, and the new 787 are all doing very well in terms of orders, in part because of A350 development delays and A380 operational problems, like wing cracks, described by Flottau (2012). Though it is anticipated that sales will grow somewhat, as shown in Figure 1.2, there is concern that the world economic situation in general, and the rapidly escalating fuel prices in particular, may reduce these estimates. The former suggests possible drops in demand while the latter forces fleet upgrades to newer, more fuel-efficient aircraft. The net result is currently uncertain, though precipitous drops in sales are unlikely. In any event, the backlog of orders is currently so large that if there is a drop-off in sales the effects won’t be felt for several years, giving manufacturers an opportunity to revise their business strategies.

The Boeing Current Market Outlook (2012) calls for about 34,000 new commercial aircraft to be delivered over the next 20 years, as shown in Figure 1.3, constituting a doubling of the fleet in service. The major segment of this new growth in airplane deliveries is predicted to be in single-aisle, or narrow-body, aircraft, a segment expected to more than double in size. This reflects Boeing’s confidence in the move toward more direct flights, rather than hub and spoke flights, and this outlook is felt to be in response to passenger demand, as well as the prospect for reduced fuel burn by using more direct flights.

Figure 1.3 Number of new aircraft deliveries forecast by Boeing Current Market Outlook (2012) for the period 2011–2030 grouped according to aircraft type.

This potential growth is also encouraging new aircraft manufacturers. China, Russia, and Japan are all developing 70–90-seat regional jets providing direct competition to current regional jet leaders Embraer and Bombardier. However, the regional jet market is seen to be relatively weak and all these manufacturers are contemplating moves toward larger size (100 plus seats) jets where they will be starting to compete with Boeing and Airbus. The short-range, or regional, market is slowly returning to turboprop-powered aircraft, largely because of the better fuel economy they offer.

However, another passenger demand is increased comfort and this is best filled by twin-aisle, or wide-body, aircraft. Not only are pressures from business travelers making international carriers expand their business class sections, but now seats that fold flat into beds are becoming a major factor in airline competition. The long-range capabilities of newer aircraft make these upgrades increasingly important. It is not unusual to have 16- and even 18-hour flights, like Singapore Airlines’ direct flight from Singapore to Los Angeles and to Newark. Although the projected number of twin-aisle aircraft to be delivered in the 20-year period is only about one-third that of single-aisle aircraft, the market value of the twin-aisle aircraft is about the same as that of the single-aisle aircraft, as illustrated in Figure 1.4. The Boeing Current Market Outlook (2012) forecast for the change in the size and make-up of the fleet is summarized in Figure 1.5 which shows the fleet complexion in 2011 compared to that projected for the year 2030.

Figure 1.4 Market value of new airplane deliveries forecast by Boeing Current Market Outlook (2012) for the time period 2012–2030 grouped according to aircraft type.

Figure 1.5 Forecasts for the change in the size and make-up of the fleet by the year 2030 grouped according to aircraft type.

The Boeing Current Market Outlook (2012) also highlights the rapid growth and industrialization of the Asia-Pacific region as illustrated by the market value share breakdown according to region shown in Figure 1.6. China is expected to lead in capacity growth over the period considered, at a rate of about 8% and by 2027 will have half the traffic of the North American market. Currently it has less than 20% of that market. Expansion of the European Union and the Commonwealth of Independent States of the former Soviet Union is expected to result in their domestic traffic overtaking the North American domestic traffic in the near term, then falling back to a lesser value by 2026.

Figure 1.6 Forecast of the market value of the purchases of new aircraft during the time period of 2012–2031. Total market value = $4.5 trillion.

The International Civil Aviation Organization (ICAO) released preliminary figures for the year ending 2011 indicating that passenger traffic on the world’s airlines increased by about 6.5% over 2010, in terms of passenger-kilometers performed, according to ICAO (2011). Passengers carried on scheduled services grew by around 5.6% to 2.7 billion; the trend over the past 10 years is illustrated in Figure 1.7. Statistics supplied by ICAO’s 190 Contracting States also show an overall increase of about 4.3% over 2010 based on metric ton-kilometers performed; this is a measure which includes passenger, freight, and mail traffic. The global passenger load factor was 78%, about the same as in 2010. Freight carried worldwide on scheduled services in 2011 went up to approximately 51.4 million metric tons compared with about 50.7 million metric tons in 2010.

Figure 1.7 Airline passengers carried over the 10-year period 2002–2011 as reported by the ICAO (2011).

The ICAO points out that the continued high growth rates in passenger traffic across all regions in a difficult world economic environment was a positive for 2011. They forecast 3.5% growth in the world economy over the next 2 years resulting in a 6% growth in revenue passenger-kilometers over the same period. However, the uncertainty regarding the weakly growing economy in the United States and Europe, which could expand to other regions, coupled to the erratic behavior of growing fuel prices makes predictions questionable.

1.2 Technology drivers

Airliner design is a rather mature field and it is unlikely that improvements will involve breakthroughs. Instead, the persistent application of small cumulative advances will provide competitive advantages for the manufacturer that can successfully integrate them into their product. The areas of greatest promise center around reductions in weight, drag, and engine emissions, as well as noise abatement techniques. Wall (2006) reported on the initiation of a “Clean Sky” program by the European Union as a major part in the Aeronautics and Air Transport portion of its 7-year, $69 billion, Seventh Framework Program. The objective was to research an array of emissions-reducing technologies that could be ready enough to be incorporated into designs for aircraft entering service around 2020. This aeronautical research program, which included demonstrator engines, was funded at a level of about $2 billion and now a second, larger phase, to run through the 2014–2016 period is being drawn up, according to Warwick (2012).

In the summer of 2006 jet fuel prices rose to over $2.20 per gallon in New York and remained fairly stable through the summer of 2007. However, by the summer of 2008 the price almost doubled, increasing to almost $3.85 per gallon. During the global economic slump of 2008–2009 the price dropped back down to about $1.25. By 2011 the price had slowly climbed back up to around $3.00 and has remained around that value through the middle of 2012. Crude oil futures costs are volatile and are expected to average $115 per barrel, leaving most manufacturers feeling the pinch to improve fuel economy. After a brief period of profitability following the losing years between 2002 and 2006, the airlines are again facing the prospects of substantial losses and are seeking new ways to reduce costs. Boeing’s emphasis on designing the new 787 as a particularly fuel-efficient airliner has proven to be a remarkably good decision. Airbus has looked to the A350 to provide similar attractiveness to the airlines. In the high-volume single-aisle narrow-body aircraft category the fuel efficiency mantra has been at the center of the heated battle between the B737Max and the A320Neo, even though both are still in the development stage, as noted by Norris (...

Table of contents

• Cover
• Title page
• Table of Contents
• Copyright
• Preface
• Introduction and Outline of an Airplane Design Report
• Chapter 1: Market Survey and Mission Specification
• Chapter 2: Preliminary Weight Estimation
• Chapter 3: Fuselage Design
• Chapter 4: Engine Selection
• Chapter 5: Wing Design
• Chapter 6: Tail Design
• Chapter 7: Landing Gear Design
• Chapter 8: Refined Weight and Balance Estimate
• Chapter 9: Drag Estimation
• Chapter 10: Aircraft Performance
• Chapter 11: Aircraft Pricing and Economic Analysis
• Appendix A: Airfoil Characteristics
• Appendix B: 1976 US Standard Atmosphere Model
• Appendix C: Airfoil and Wing Theory and Analysis
• Appendix D: Graphs of Critical Mach Number
• Appendix E: Units and Conversion Factors
• Appendix F: General Database for Commercial Aircraft
• Index