Conceptual Aircraft Design

13Aircraft Power Plant Performance

13.1 Overview

Chapter 12 introduced various types of engines and associated theories. It also briefly discussed the topics associated with the installation effects of an engine to an aircraft. This chapter covers both uninstalled and installed engine performances. The aircraft performance engineers require installed thrust and fuel flow data to estimate aircraft performance. In most industries, aircraft performance engineers generate the installed engine performance using an engine manufacturer supplied computer program amenable to input of the various losses arising from taking engine bleed/off‐takes for aircraft systems and intake/nozzle losses.

Uninstalled gas turbine engine performances in a non‐dimensional form for some types are given in Sections 13.3–13.5. From the non‐dimensional engine data matched engine installed performances are generated. The following types of engine are given in a non‐dimensional form (except the piston engine performance). These are validated against industry standard data.

• Turbofan engine of BPR ≤ 4 (civil engine of the class T_SLS ≈ 3500 lb)
• Turbofan engine of BPR ≥ 4 (civil engine of the class T_SLS ≈ 40 000 lb)
• Medium sized turbofan engine of BPR ≤ 1 (military engine of the class T_{SLS_dry} ≈ 6000 lb)
• Turboprop engine of the class of 1000 shaft horse power (SHP) at sea level static condition
• 180 HP Lycoming piston engine

Industry standard engine performance data for classroom usage are not easy to obtain – ...