The overall fuselage length, L (see Figure 3.49) consists of the (1) nose cone, (2) constant cross-section midsection barrel, and (3) aft-end closure. The constant crosssection mid-fuselage length is established from the passenger seating arrangement and combined with the class arrangement (i. e., first class, business class, and econ – omy/tourist class). Section 4.7.6 provides seat dimensions for the two main classes (i. e., business and economy).
Aircraft length may not be equal to fuselage length if any other part of the aircraft extends beyond the fuselage extremities (e. g., the tail sweep may go beyond the tail cone of the fuselage; see Figure 6.8). Figure 4.14 shows the fuselage geometry relationship to the number of passengers. The fuselage width increases in increments with the number of passenger-abreast seating, one seat width at a time. Because of passenger comfort, a designer selects options from the sensitivity study (i. e., drag and cost variations); the continuous line in Figure 4.14 represents a typical average value. The actual width is determined in Chapter 6.