2.5 Aircraft Familiarization

10.Finalize ground/flight test schedules.

11.Complete prototype shop status schedules.

12.Revise cost analysis.

13.Begin ground tests.

14.Complete design review.

15.Continue customer dialogue and updating (no change in specifications).

Phase 4: Testing and Certification (9 Months)

1.Complete final assembly and prototype equipping.

2.Complete ground and flight tests and analysis.

3.Review analysis and modify design, if required.

4.Complete overall design review.

5.Review cost estimate.

6.Complete customer dialogue and sales arrangement.

7.Continue design review and support.

Production launch costs are typically kept separate from design and development costs. Total time to complete a project is 3 years (i.e., 2.5 years from the goahead), which is tight but feasible.

2.5 Aircraft Familiarization

This section introduces generic civil and military aircraft. Geometric definitions relevant to aerodynamic considerations are addressed in Chapter 3 and detailed descriptions of various types of aircraft and their classification are provided in Chapter 4. A diagram of aircraft with major subassemblies as components is provided herein. Indeed, aircraft design has become highly modular in the interests of the “family” concept, which facilitates low development cost by maintaining a high degree of parts commonality.

Aircraft span, length, and height are currently restricted by the ICAO to 80 m, 80 m, and 80 ft, respectively, for ground handling and storage considerations. The height is in feet but the span and length are in meters; this restriction may change. Section 1.6 highlighted the mix of SI and FPS units in aerospace engineering. In the future, only SI units will be used.

2.5.1 Civil Aircraft and Its Component Configurations

In general, the civil aircraft category includes five types: (1) small club trainers,

(2) utility aircraft, (3) business aircraft, (4) narrow-body commercial transporters (regional aircraft to midsize), and (5) wide-body large transporters. The various types of available configuration options are described in Chapter 4. The aircraft components shown in Figure 2.3 are some of the obvious ones (e.g., wing, fuselage, nacelle, and empennage); others (e.g., winglets, strakes, and auxiliary control surfaces) are less obvious but play vital roles – otherwise, they would not be included. Because there are many options, components are associated in groups for convenience, as described in the following subsections (refer to Figure 2.3).

Figure 2.3. Lockheed 1011 diagram (courtesy of Michael Niu [10])

Fuselage Group

This group includes the nose cone, the constant midsection fuselage, the tapered aft fuselage, and the tail cone. The fuselage belly fairing (shown in Figure 2.3 as several subassembly components below the fuselage) may be used to house equipment at the wing–fuselage junction, such as the undercarriage wheels.

Wing Group

This group consists of the main wing, high-lift devices, spoilers, control surfaces, tip devices, and structural wing box that passes through the fuselage. High-lift devices include leading-edge slats or trailing-edge flaps. In Figure 2.3, the leading-edge slats are shown attached to the main wing and the trailing-edge flaps and spoilers are shown detached from the port wing. Spoilers are used to decelerate aircraft on descent; as the name suggests, they “spoil” lift over the wing and are useful as “lift dumpers” on touchdown. This allows the undercarriage to more rapidly absorb the aircraft’s weight, enabling a more effective application of the brakes. In some aircraft, a small differential deflection of spoilers with or without the use of ailerons is used to stabilize an aircraft’s rolling tendencies during disturbances. In Figure 2.3, the wing is shown with winglets at the tip; winglets are one of a set of tip treatments that can reduce the induced drag of an aircraft.

Empennage Group

The empennage is the set of stability and control surfaces at the back of an aircraft. In Figure 2.3, it is shown as a vertical tail split into a fin in the front and a rudder at