Flight Performance Software FLIGHT

Flight Performance Software FLIGHT Antonio Filippone School of Mechanical, Aerospace and Civil Engineering The University of Manchester United Kingdom Updated January 2016

Report: AF-AERO-UNIMAN-2014-10

1

Summary This report is a brief description of the FLIGHT software. The software has been designed, developed and tested to carry out multi-disciplinary computational analysis of modern transport airplanes powered by gas turbine engines (e.g. turbofans and turboprops). The main features of this system include: geometric modelling, mass properties (including inertias and centre of gravity), static trim in air and on the ground, aerodynamics at all flight conditions (including airplane derivatives), propulsion models for the gas turbine engines and the auxiliary power units, propulsion models for the propeller, flight mechanics and system integration, thermophysics, including wing icing, tyre temperatures, fuel temperatures in flight, jet blast, manoeuvre analysis (including flight in a downburst), environmental analysis (including LTO emissions), aircraft noise (including real-time noise maps). This report includes a user manual and some examples of output files. Validation and verification is a main driver in the development of any sub-system. Issues of accuracy are mentioned briefly, as they are fully addressed in the published literature. Reference is done to the appropriate technical literature to point out the features of the software. A list of relevant applications is provided. [This report will updated when the software is upgraded]

Keywords: Airplane Aerodynamics, Aircraft Performance and Stability, Aircraft Noise, Aircraft Operations, Gas Turbine Engines, Environmental Emissions, Direct Operating Costs (DOC) Copyright © A. Filippone, The University of Manchester (2010-2015)

Contents Listings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3

1 Introduction 1.1 Polite Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5 6

2 System Specifications 2.1 Software Architecture . . . . . . . . . 2.1.1 Release Notes . . . . . . . . . . 2.1.2 Units and Dimensions . . . . . 2.2 Airplane Models and Input Structure . 2.3 Program Start . . . . . . . . . . . . . 2.3.1 Caveats and Limitations . . . . 2.4 Output Files . . . . . . . . . . . . . . 2.5 Modules and Models . . . . . . . . . . 2.5.1 Geometry Module . . . . . . . 2.5.2 Structures and Weight Module 2.5.3 Aerodynamics Module . . . . . 2.5.4 Propulsion Module . . . . . . . 2.5.5 Propeller Module . . . . . . . . 2.5.6 Flight Mechanics Module . . . 2.5.7 Performance Module . . . . . . 2.5.8 Optimisation Module . . . . . 2.5.9 Environmental Module . . . . . 2.5.10 Aircraft Noise Module . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . .

7 7 9 10 11 12 13 13 14 14 16 17 19 19 20 21 21 22 23

3 Guide to User Menu 3.1 Top Level . . . . . . . . . . . . . . . . . . 3.1.1 Performance Charts Sub-Menu . . 3.1.2 The WAT Charts sub-menu . . . . 3.1.3 Mission Analysis Sub-menu . . . . 3.1.4 Aircraft Noise Sub-menu . . . . . . 3.1.5 Propeller Noise . . . . . . . . . . . 3.1.6 Noise Calculations Outputs . . . . 3.1.7 Exhaust Emissions Sub-Menu . . . 3.1.8 Flight Optimisation Sub-menu . . 3.1.9 Manoeuvre Analysis Sub-menu . . 3.1.10 Trim Analysis Sub-menu . . . . . . 3.1.11 Direct Operating Costs Sub-Menu

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

26 26 27 29 29 31 37 37 38 38 39 39 39

. . . . . . . . . . . . . . . . . .

2

3 3.2 3.3

. . . . . .

41 43 44 44 45 45

4 Guide to Propeller Code 4.1 User Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

46 46

5 Case Studies 5.1 Aerodynamics . . . . . . . . . . . . . . . . . . . . . . . 5.2 Airframe-Engine Integration: SAR Charts . . . . . . . 5.3 Thermo-physics: Simulation of Fuel Tank Temperature 5.4 Aircraft Noise . . . . . . . . . . . . . . . . . . . . . . . 5.5 Operational Performance: Payload-Range . . . . . . . 5.6 Longitudinal Dynamics . . . . . . . . . . . . . . . . . 5.7 Propeller Performance . . . . . . . . . . . . . . . . . .

. . . . . . .

50 50 51 51 52 52 53 53

. . . . . . .

58 58 60 61 62 63 65 69

3.4

Batch Jobs (Linux/Unix Version) . . . . . . Other Tools . . . . . . . . . . . . . . . . . . 3.3.1 How to Restart a Footprint Analysis 3.3.2 Aerodynamic Tools . . . . . . . . . . 3.3.3 Propulsion Tools . . . . . . . . . . . Error Messages . . . . . . . . . . . . . . . .

. . . . . .

. . . . . .

. . . . . .

. . . . . .

. . . . . .

. . . . . .

. . . . . .

. . . . . . .

. . . . . .

. . . . . . .

. . . . . .

. . . . . . .

. . . . . .

. . . . . . .

. . . . . .

. . . . . . .

6 Selected Output Files & Data 6.1 AEO Take-off of an A320 Model . . . . . . . . . . . . . . . . . 6.1.1 AEO Climb of an Airbus-A320 Airplane Model . . . . . 6.1.2 Cruise Performance of an Airbus A320 Airplane Model . 6.1.3 En-Route Descent of an Airbus A320 Airplane Model . 6.1.4 Mission Report of an A320 Model . . . . . . . . . . . . 6.2 Nomenclature & Conventions . . . . . . . . . . . . . . . . . . . Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . .

. . . . . . .

. . . . . . .

. . . . . .

. . . . . . .

. . . . . . .

. . . . . .

. . . . . . .

. . . . . . .

. . . . . .

. . . . . . .

. . . . . . .

. . . . . .

. . . . . . .

. . . . . . .

. . . . . .

. . . . . . .

. . . . . . .

. . . . . .

. . . . . . .

. . . . . . .

. . . . . .

. . . . . . .

. . . . . . .

. . . . . .

. . . . . . .

. . . . . . .

. . . . . .

. . . . . . .

. . . . . . .

A List of User-Defined Parameters

71

Index

74

Listings 2.1 2.2 2.3 2.4 2.5 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 3.20 3.21 3.22 3.23 3.24 3.25 3.26 4.1 4.2 4.3 4.4 A.1 A.2 A.3

Version of Software System and Database . . . . . . . . . . . . . . . . Wetted Areas of the G550 . . . . . . . . . . . . . . . . . . . . . . . . Mass distribution of the G550 . . . . . . . . . . . . . . . . . . . . . . Cruise drag of the Airbus A320-211 . . . . . . . . . . . . . . . . . . . Noise stacks options . . . . . . . . . . . . . . . . . . . . . . . . . . . . Analysis Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Performance charts options . . . . . . . . . . . . . . . . . . . . . . . . Take-off options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Performance Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mission Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Updating Atmospheric Winds . . . . . . . . . . . . . . . . . . . . . . Updating Mission Data . . . . . . . . . . . . . . . . . . . . . . . . . . Aircraft Noise Sub-Menu . . . . . . . . . . . . . . . . . . . . . . . . . Aircraft Noise Options . . . . . . . . . . . . . . . . . . . . . . . . . . Noise Footprint Options . . . . . . . . . . . . . . . . . . . . . . . . . . Options for Calculating footprints from multiple movements . . . . . Template of directivity file . . . . . . . . . . . . . . . . . . . . . . . . . Noise sub-options menu, propagation models . . . . . . . . . . . . . . Nose sub-options menu, propagation models . . . . . . . . . . . . . . . Output data in noise breakdown files . . . . . . . . . . . . . . . . . . . Aircraft Emissions Sub-Menu . . . . . . . . . . . . . . . . . . . . . . . Flight Optimisation Sub-Menu . . . . . . . . . . . . . . . . . . . . . . Aircraft Trim Sub-Menu . . . . . . . . . . . . . . . . . . . . . . . . . DOC File Notes (refer to Listing 3.20) . . . . . . . . . . . . . . . . . . DOC File (template) . . . . . . . . . . . . . . . . . . . . . . . . . . . Batch job file for noise footprints . . . . . . . . . . . . . . . . . . . . . Batch job file for noise sensitivity analysis . . . . . . . . . . . . . . . Batch job file for noise calculations . . . . . . . . . . . . . . . . . . . Output of batch job file for noise calculations (cost functions.txt). Typical configuration file aerotool.cfg. . . . . . . . . . . . . . . . . Typical configuration file enginetool.cfg. . . . . . . . . . . . . . . . Propeller Analysis Options . . . . . . . . . . . . . . . . . . . . . . . . Non-axial flow performance . . . . . . . . . . . . . . . . . . . . . . . . Operational conditions for propeller noise (default) . . . . . . . . . . Propeller design data . . . . . . . . . . . . . . . . . . . . . . . . . . . User-Defined Parameters, Part 1 . . . . . . . . . . . . . . . . . . . . . User-Defined Parameters, Part 2 . . . . . . . . . . . . . . . . . . . . . User-Defined Parameters, Part 3 . . . . . . . . . . . . . . . . . . . . . 4

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10 16 17 19 24 26 27 29 29 29 30 30 32 33 33 34 35 36 36 37 38 38 39 39 40 41 41 42 42 44 45 46 47 48 49 71 71 72

Chapter 1

Introduction In this document we give a brief description of the comprehensive flight mechanics program FLIGHT. Some relevant publications on this program are listed at the end of this document. Publications exist on the general framework 1;2;3;4 , on aircraft performance 5;6;7;8;9 , on aircraft noise 10;11;12;13;14;15;16;17 and environmental emissions 18;19 . Additional bibliography related to the theoretical background of this software is given in the papers and books cited. This report is not a theory manual. Although the program is fully multi-disciplinary, one of its main strengths is its environmental capability in the following areas: Configuration aerodynamics Exhaust emissions as function of passengers, bulk payload, range and service items Optimum fuel planning, including five options for fuel reserves Landing and take-off (LTO) emissions Noise trajectories at FAR points and noise footprints for single-event aircraft movements Aircraft noise from stacking patterns Contrail formation and contrail avoidance paths. 7;19

There are various optimization modules that allow, among other things, to estimate the best fuel load in the presence of fuel price differentials (tankering) and costs index (based on time, fuel costs and environmental taxes). The code can be further used for noise trajectories optimizations, minimum ground emissions, etc., with ancillary computer programs. Typical applications include: Mission Analysis and Field Performance Trajectory Optimization & Route Planning Environmental Emissions and Fuel Costs Aircraft Noise Trajectories Noise Impact around Airports Airframe-Engine Integration Systems Analysis Thermo-Physics and Dynamics Verification of Performance Data

5

1 Introduction

6

Unbiased Competition Analysis Trade-off Studies Training & Professional Development Engineering Projects.

The program can be adapted to interface with finite-element codes for the analysis of systems such as tyres, or with CFD codes for wing aerodynamics and jet dispersion, or with optimal control programs to optimise flight trajectories with a variety of cost functions. The FLIGHT software, in its current form, is not suitable for preliminary aircraft design. There is number of computer codes available for this purpose. The number of inputs required for any given aircraft is so large (hundreds of parameters, in fact) that it would not be possible to contemplate multi-disciplinary design. FLIGHT is being fully documented and demonstrated in the technical literature, with a growing number of cases. Examples are reported in Chapter 5. However, simple trade-off studies can be carried out with ad-hoc routines, that allow, inter alia, the analysis of morphing wings 20 , the parametric effects of wing areas and structural weights, and sensitivity analysis of component wetted areas. The development of an aircraft model relies on official documentations for the airplane, including the flight manual (where available), the type certificate documents (from EASA, FAA, CAA), manufacturers data (where possible), and other reliable published data. Reliable does not mean true, and in fact a good deal of cross-analysis is required to extract quantitative data of engineering use. Typical examples include: engine details, propeller geometry, flap geometry, and APU data. The role of FLIGHT is to promote a step change in the prediction and analysis of aircraft flight performance, through physical principles and rigorous validation across disciplines. In this code, there is a departure from closed-form solutions of classical mechanics, and a widespread use of numerical methods. We have gained considerable experience in data analysis, verification of performance/design data, sensitivity problems, propulsion integration and more* . The program is written in Fortran 95, with some interface tools written in Matlab. It is optimized for numerical performance. The program runs as an executable under Linux and Windows 7 and above. On request, we can provide a DLL (dynamic link library) version and interface with other software.

1.1

Polite Notice

The FLIGHT program models real-life aircraft on the basis of technical information available in the open domain. This information includes the Type Certificates (airplane, engines, propellers), airworthiness data, data published by the manufacturers through their websites and the relative documentation; periodic publications by the manufacturers, industry documents, conference proceedings, technical papers, contract reports, etc. No proprietary information is disclosed. The Author cannot accept responsibility for any action resulting in damage, accident or loss as a consequence of using the FLIGHT program. None of the graphs and figures can be used to make a final judgement on any aircraft, any manufacturer, any flight, any service or any design. If you are in doubt, please consult the Author, seek professional advice or use the performance programs from the aircraft manufacturers. * The Author runs an advanced course in Aircraft Flight Performance for continuing professional development; interested users are welcome to initiate contact for arranging such courses, at Manchester or other locations.

Chapter 2

System Specifications 2.1

Software Architecture

Examples of software architecture are given in the flow charts shown in Figure 2.1. A summary of typical user parameters for a complete mission calculation is given in Table 2.1. The code contains modules for geometry and the reconstruction of the airplane; for aerodynamics, propulsion, stability, performance, noise, thermodynamics, tyre dynamics, and more. The “Database” block contains external data that are required for a variety of tasks, and are separate from the airplane input deck. We are convinced that this is the most comprehensive approach to performance available today.

Figure 2.1: Disciplines modelled in FLIGHT program, adapted from Ref. 16 .

7

2 System Specifications

Flight

8

Table 2.1: Summary parameter settings for complete flight calculation. Parameter Notes

Taxi-out

Take-off Climb to ICA

Cruise

Descent

Final approach Landing

Contingency

Operational Data

Atmosphere Noise abatement Other parameters

Roll speed Roll distance to runway Idle time Roadway temperature Tentative Flap setting Engine derating Engine derating KCAS of 1st segment Final KTAS of 2nd segment KCAS of 3rd segment Climb procedure between FL Switch procedure between FL CG shift and trim procedure Descent to FL specified by final KIAS KCAS of 2nd segment to 10,000 feet KCAS of 3rd segment to 1,500 feet Glide slope Several flight control parameters Stopping procedure (ailerons, brakes, etc.) Flap settings Roadway temperature Diversion parameters Holding parameters Reserve policy On-board passenger services Baggage allowance Bulk cargo Initial CG position Air temperatures Winds at all flight segments Climb-out procedure Final approach flight path Aerodynamic deterioration (profile drag) Engine deterioration (fuel flow)

constant

const/variable const/variable can be optimised can be optimised can be optimised

automatic at cruise

steep approach const/variable

kg/pax kg/pax ≥0

constraints constraints

The [Noise] module can run almost as a stand-alone code, if one has a suitable aircraft trajectory. A special format is required; this is not available in the demo version. In practice, it is possible to map an arbitrary flight trajectory to an airplane model and calculate the corresponding noise signature. Furthermore, it is possible to dissociate the acoustic sources from the propagation, so that the noise propagation model can be run on a different set of acoustic sources. The [Noise] modules contains state-of-the art implementations of for the systems components and the most accurate numerics to simulate effects such as atmospheric propagation, ground effect and the effects of wind shear, with arbitrary wind directions and arbitrary humidity levels.


9

Figure 2.2 shows a breakdown into sub-systems, which are modelled separately, and then assembled to construct the full aircraft. About 25 major sub-systems are modelled.

Figure 2.2: Breakdown of the aircraft into system components.

1. Fuselage System: nose, central section, wing-body blend, tail section, nacelles, pylons. 2. Wing System: wing, ailerons, winglets, spoilers, flap racks. 3. High-Lift System: inboard/outboard flaps, inboard/outboard slats. 4. Tail System: horizontal and vertical tails, rudder, elevators. 5. Propulsion System: gas turbine engines, APU, propellers, intake ducts, acousic liners. 6. Landing Gear System: main/nose undercarriage (struts, bays, tyres). 7. Other Systems: external fuel tanks.

2.1.1

Release Notes

We have a version control for most of the sub-systems, as indicated in the chart in Figure 2.3. The software version refers to the actual computer code, including all the source files, headers, makefiles, project options (optimization, debugging, linking, etc.). The database version refers to validated airplane models. This version control has three sub-sets of controls, such engine models, geometry/bitmap model, propeller model (if relevant). The engine version refers to the flight envelopes and all the functional details of the engine, including design limitations, database of emissions, design operation point, etc. The geometry/bitmap model refers to the actual geometry


10

Airframe FLIGHT

Figure 2.3: Software version control. Engine

PropNoise FLIGHT of the aircraft stored in a bitmap file. Parsing of this file is done through the [Geometry] model Propeller of the software; updates to the latter ones corresponds to updates in the software version. A typical output will contain the software specifications in Listing 2.1.

Database

APU

Listing 2.1: Version of Software System and Database FLIGHT V e r s i o n Revision Database PropNoise Build Licensed to

: : : : : :

6.8.1 a 19.3.3 3.8.1 3984/44.3% Owner

A i r p l a n e : Airb us A320 −211; Engine : CFM56−5C4P ; APU : 131−9

2.1.2

Model

Software

Version 1 . 2 . 2 Version 3 . 1 . 1

Units and Dimensions

The code works this international units (SI) whenever possible. Unfortunately, aviation still prefers imperial units, and unless conversions are done, it is impossible to compare data. Although the use of kg (for mass) and Newton (force) have become increasingly widespread, pounds and feet still govern the official documents. For this reason, sometimes the output data are printed in imperial units, although as a general rule we have Masses are given in [kg] or metric tons: 1 ton = 103 kg. Weights are given in [kg] or metric tons, like the mass, e.g. 1 ton-weight = 1 ton-mass. The pound [lb] force is never used. Ranges on output are both [km] and nautical miles [n-mile]. Altitudes on output are [km], [feet] or flight levels FL (FL330 = 33,000 feet). Velocities on output are [m/s], [km/h] and [kt]; descent rates are also in [feet/min].


2.2

11

Airplane Models and Input Structure

The input deck consists of several contributions. More specifically, there are the following data: Airplane Deck, with general data, aerodynamic derivatives, certified limitations, and a database needed to reconstruct the full geometry of the airplane. [We can provide additional airplane models.] Engine Deck, with data and certified limitations, and a series of steady-state performance charts that represent the full envelope of the engine over a range of atmospheric temperatures (with a ±20 variation around the standard day). Each database contains anything up to 90 aero-thermodynamic parameters, only 20 of which are effectively used for noise calculation. [We can provide additional engine models.] Propeller Deck, with propeller geometric data, operating limitations, blade sections, and flight envelopes. [We can provide additional propeller data sets.] APU Deck, which contains data for the calculation of APU performance (such as fuel flow, electrical load, noise).

Other data of practical interest include: ISA atmosphere, cold and hot day. Headwind and tailwinds (for flight performance). Arbitrary wind directions (for noise propagation). Relative humidity (only for aircraft noise and contrail analysis). Turbulence levels (for turbulent transition and noise propagation). Ground properties (for ground performance and noise propagation).

Key to the modelling of the airplane is a bitmap file, that contains control points for the reconstruction of the airplane. An example of how control points are defined in shown in Figure 2.4. FLIGHT has a set of internal rules for parsing these points and define the complete geometry with a realistic accuracy. Although a CAD model would be needed, data generally available do not allow sufficient flexibility to take on this task; in the future this aspect could be reconsidered. A more detailed example of the use of control points is shown in Figure 2.5, which shows the cross-section of the ATR72-500 model. Normally, the atmospheric data are included into an operation file, which collects data such as take-off and landing conditions (airfield altitude, wind speeds, temperature, humidity, etc.). However, some of these data can be changed through a user interface option. There are three basic input files: a file that defines the operational conditions of the flight; a file that defines the airplane; a file that defines the basic parameters of the engines. In addition, there are a number of files used to create generic wing sections. These are supercritical airfoils that are scaled for the case under study. A complete flowchart of the airplane model is shown in Figure 2.6. These data sets are collected in ./Airplanes/Airplane name/..


12

Figure 2.4: Example of control points to define an airplane geometry.

Wing-Body 4

y, m

3

Cylindric fuselage

2

1

Body Fairing 0

-2

-1

0

1

2

x, m

Figure 2.5: Frontal view of the ATR72 cross-section: control points to define an airplane fuselage.

2.3

Program Start

Two versions of this program are provided: Linux tarred file: unzip/untar the file, which will self-install. There will be an executable file called go in the working directory. To run, enter command ./go. MS Windows zipped file flight*.zip. Unzip to self-install. The executable is called flight*.exe in the working directory.


13

Limitations

Bit Bitmap d data t Limitations

Airframe

Engine

Configuration FLT Envelope

AERO Derivs

Figure 2.6: Flowchart of a complete airplane model. FLIGHT

After running successfully, all output files are moved into the ./Outputs folder. If the program Blade Sect. Sect has terminated abruptly, the output files remain in the working directory. To clean up the mess, run the clean batch file, which will eventually move the appropriate location. NoteConfiguration AERO Polarsthe files to Propeller APU that existing files are overwritten. Old files must be stored to prevent results being lost. The user Envelope should get acquainted with the output data,FLT since more than 100 different files are available forFLT Envelope analysis, some of which contain extensive amount of data.

2.3.1

Caveats and Limitations

There are several cases that do not lead to feasible solutions, including high winds, high weights, range beyond design range, too heavy gross weight, etc. We cannot provide a full list of possibilities; the user should get acquainted with the limitations of the flight model when the envelope of the airplane is exceeded. In most cases, there is a clear error message on screen to advise the user of possible causes of errors and/or limitations. When the error is not recognized, it is possible that the program will terminate by aborting the run. The FLIGHT software has been developed in an academic environment. It has a strong theoretical basis, a rational path to validation and verification (all published in the specialized literature). The Demo version comes as it is, with no warranty, expressed or implied, that it fits any particular application in industry, engineering or education. The code should only be used by professionals who have a good grasp of aircraft flight and an understanding of the engineering practice.

2.4

Output Files

Following the various analysis options, there can be as many as 100 output files. Not all these files are available at the same time. Although the names of these files should be self-explanatory, trying to find out the actual data can be difficult. For this reason, the output files are sorted into several sub-folders, as described below: All report files, called report*.out are moved to ./Outputs/Airplane/Reports/..


14

All the geometry files are moved to the sub-folder ./Outputs/Airplane/Geometry/.. All the noise files, with the exception of the report files, are moved to the sub-folder ./Outputs/Airplane/Noise/.. All the flight mission files are moved to the sub-folder ./Outputs/Airplane/Mission/.. All the engine files are moved to the sub-folder ./Outputs/Airplane/Propulsion/.. Most of the charts are moved to the sub-folder ./Outputs/Airplane/Charts/.. All the remaining files remain in the ./Outputs folder and can be rearranged by the user.

All files are in ASCII. Data files *.out can be plotted with a variety of programs. However, we make use of Tecplot (www.tecplot.com). A Matlab interface is also available for selected outputs.

2.5

Modules and Models

We now describe separately the main features of the models implemented in the FLIGHT program.

2.5.1

Geometry Module

Construction of the airplane with two different methods: stochastic and analytic, with higherorder interpolation. In particular, the module provides the sub-components listed in the next page. For most components, the program provides main dimensions in a cartesian reference, centroids (calculated with respect to a reference point on the nose), aspect-ratios (if applicable), angles and wetted areas. The recognised geometry components are: 1. Wing geometry. 2. Horizontal tail and elevator. 3. Wing fuel tanks geometry and capacity. 4. External fuel tanks. 5. Flaps, slats, ailerons, spoilers, flap racks and winglet geometry. 6. Vertical tail and rudder. 7. Nacelles and pylons. 8. Fuselage geometry and partitions. 9. Under-carriage geometry, including bays. 10. Other surfaces, such as spoilers and unnamed items. 11. Aircraft volumes. 12. Engine nozzles. 13. Refuelling probes.


15

The latter element is also part of the propulsion module. For all the components, the module provides planform areas, aspect-ratios, overall dimensions, centroids, wetted areas and volumes, Figure 2.7. These quantities are used in the various phases of calculation, including the aerodynamic model. Wing areas are calculated according to three different methods. The user may want to know at least that the exposed wing area refers to the area outside the fuselage (or wing box), and is corrected for dihedral effects. The reference area is calculated by adding the wing.

4

spanwise choordinate, m

2

3

3

2

1

4

1 0

24

25

26

27

28

X-coordinate from nose, m

Figure 2.7: Reconstruction of a horizontal tail plane system from the bitmap database. Since the wing area can be defined in a number of ways, the resulting mean aerodynamic chord (MAC) can also be variable; thus, a decision must be taken, particularly when attempting to perform calculations that are strongly dependent on the MAC. Such cases include at least longitudinal trim conditions and cruise drag. Some manufacturers refer to a “reference chord”, rather than a MAC, so it is unclear what a 25% MAC refers to. The construction of the geometry starts from a geometry file, which is a summary of control points (such as shown in Figure 2.4) taken from three views of the airplane (top, side, front). Typically, 300 to 400 control points are used to create a “wireframe” of the airplane. In this model, raw data such as “wing area” or “wing span” are not used. The resulting parameters are compared, if possible, with the manufacturer’s official data. There is no other practical way of describing the geometry of the airplane in absence of CAD drawings. However, a considerable amount of detail can be extracted, including the wetted area breakdown, the cross-sectional area distribution, position of reference points, etc. Figure 2.7 shows the construction of the horizontal tail system of the ATR72-500. Listing 2.2 shows a summary of wetted areas calculated for the Gulfstream G550.


16 Listing 2.2: Wetted Areas of the G550

Airplane Engine APU

= G u l f s t r e a m G550 ; = BR710A1−10 ; = Re−220 ;

Version 1 . 0 . 1 Version 4 . 1 . 1 Version 1 . 0 . 0

Wetted Areas Summary −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Fuselage = 1 6 6 . 9 1 [ m2 ] , 33.65 % −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Nose = 2 2 . 8 2 [ m2 ] , 4.60 % Center = 1 0 8 . 9 5 [ m2 ] , 21.96 % Aft = 2 9 . 6 4 [ m2 ] , 5.97 % * * [ Wing−body b l e n d ] = 5 . 4 9 [ m2 ] , 1.11 % −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Wing = 1 9 0 . 6 7 [ m2 ] , 38.43 % Wing t i p s = 0 . 0 0 [ m2 ] , 0.00 % Winglets = 5 . 2 1 [ m2 ] , 1.05 % Horizontal Tail = 4 7 . 7 6 [ m2 ] , 9.63 % Vertical Tail = 3 1 . 2 9 [ m2 ] , 6.31 % Nacelles = 4 5 . 6 8 [ m2 ] , 9.21 % Pylons = 8 . 5 7 [ m2 ] , 1.73 % Flap r a c k s = 0 . 0 0 [ m2 ] , 0.00 % −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− T o t a l wetted a r e a = 4 9 6 . 0 9 [ m2 ] , 5340. [ Wet area / Wing Area = 4.712 Wing Area / Wet area = 0.212 Gross ( wetted ) f u s e l a g e s h e l l a r e a =

[ c o r r e c t e d f o r r o o t wing s e c t i o n ] [ corrected for root t a i l section ] [ included in central section ]** [ c o r r e c t e d f o r f l a p r a c k s , 0 m2 ]

ft2 ]

1 6 2 . 8 4 [ m2 ]

Wetted Areas ( o t h e r components , e s t i m a t e d ) −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− All Flaps = 1 4 . 6 [ m2 ] , 2.9 % All Slats = 0 . 0 [ m2 ] , 0.0 % All Spoilers = 1 1 . 3 [ m2 ] , 2.3 % −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Rudder = 7 . 1 [ m2 ] , 1.4 % Elevator = 5 . 9 [ m2 ] , 1.2 %

2.5.2

Structures and Weight Module

This module provides an estimate of the structural mass distribution of the airplane. In general, this should not be required for operational performance, and it is the subject of aircraft design. However, the structural mass distribution is required in order to estimate the moments of inertia of the airplane. Listing 2.3 shows the predicted structural weight of the G550. This module provides: Structural mass distribution (empty airplane) Vertical position of CG (empty airplane; cruise and take-off configuration) Longitudinal position of CG (empty airplane; cruise and take-off configuration) Roll moment of inertia (empty airplane; cruise and take-off configuration) Pitch moment of inertia (empty airplane; cruise and take-off configuration)


17

Pitch moment of inertia (empty airplane; cruise and take-off configuration) Radii of gyration (x,y,z) for the configurations above.

Listing 2.3: Mass distribution of the G550 Airplane Engine

= G u l f s t r e a m G550 ; = BR710A1−10 ;

Version 1 . 0 . 1 Version 4 . 1 . 1 ;

APU = Re−220

A i r p l a n e Mass/ Weight Report −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Sh ell Fuselage = 3 4 5 3 . 6 [ kg ] 16.39[%] Nose S e c t i o n = 1 5 8 . 9 [ kg ] 0.75[%] Central Section = 3 0 8 8 . 4 [ kg ] 14.66[%] Tail Section = 2 0 6 . 3 [ kg ] 0.98[%] Fuselage f l o o r = 2 4 3 . 4 [ kg ] 1.16[%] Wing System = H−T a i l System = V−T a i l System =

3 7 8 4 . 1 [ kg ] 6 0 7 . 3 [ kg ] 3 2 4 . 1 [ kg ]

Landing Gear System Nose Landing Gear Tyres Rolling stock Structures Main Landing Gear Tyres Rolling stock Structures

= = = = = = = = =

1 6 3 0 . 4 [ kg ] 2 7 1 . 5 [ kg ] 5 0 . 0 [ kg ] 1 0 0 . 0 [ kg ] 1 7 1 . 5 [ kg ] 1 3 6 8 . 7 [ kg ] 9 0 . 0 [ kg ] 2 7 9 . 0 [ kg ] 9 9 9 . 7 [ kg ]

P r o p u l s i o n System Engines N a c e l l e / Pylons Other APU mass

= = = = =

5 8 1 2 . 1 [ kg ] 3 7 0 2 . 0 [ kg ] 2 1 1 0 . 1 [ kg ] 0 . 0 [ kg ] 1 0 9 . 0 [ kg ]

17.96[%] 2.88[%] 1.54[%] 7.74[%] 1.29[%] 0.24[%] 0.47[%] 0.81[%] 6.50[%] 0.43[%] 1.32[%] 4.74[%] 27.58[%] 17.57[%] 10.01[%] 0.00[%] 0.52[%]

Furnishings = 8 4 0 . 0 [ kg ] 3.99[%] Seats = 5 8 8 . 0 [ kg ] 2.79[%] Other = 2 1 0 . 0 [ kg ] 1.00[%] ALL Systems = 4 2 5 9 . 5 [ kg ] 20.21[%] −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− TOTAL* = 2 1 0 7 3 . 5 [ kg ]

The theoretical model assumes that the systems are uniformly distributed on the airplane. This is required for the correct determination of the CG and the moments of inertia. Although it is generally not true, there is not enough information in order to make a quantitative assessment about their contribution. Engine geometry details are likewise extracted from photographs, either taken by the Author or from the public domain (for example: Google images and related websites). As an example, we show in Figure 2.8 the sizing of the components from a digital image.

2.5.3

Aerodynamics Module

The module calculates the total aerodynamic drag by component at all steady-state flight conditions. In particular, it provides:


18

Figure 2.8: Reconstruction of engine geometry (aft portion) from digital photography. Induced drag of wing and horizontal tail plane with elevator. Iterative planform wing design for cruise CL at zero attitude. Ground effect on induced drag of the wing. Aerodynamic center of wing and horizontal tail. Wave drag of the wing, horizontal tail, vertical tail. Wave drag of fuselage forebody. Aerodynamic derivatives of wing, H-stabilizer, V-stabilizer. Aerodynamic derivatives of elevator, flap, rudder. Laminar-turbulent transition on the wing, H-stabilizer, V-stabilizer. Profile drag of all lifting components: wing, tail, flaps, winglet, etc. Profile drag of fuselage, nacelles, pylons, external fuel tanks. Under-carriage drag, including bays and open doors. Interference drag at all major junction (fuselage-wing, etc.). Excrescence drag. Trim drag (see Stability & Control, § 2.5.6). Drag of idle engines. Airplane’s drag polar. Buffet boundaries.

Listing 2.4 shows an example of drag estimate at cruise condition of an Airbus A320-211 airplane model. This is an extract of a report called report drag.out.


19 Listing 2.4: Cruise drag of the Airbus A320-211

Maximum O p e r a t i n g Mach number , MMO = Maximum Dive Mach number , MD =

0.820 0.877

F u s e l a g e Drag Breakdown −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− F l i g h t Alt = 10.058 [ km ] 33000. [ f e e t ] Mach = 0.790 Avg S kin CD = 0 . 0 0 7 9 0 42.1 [%] nose = 0.00186 9 . 9 [ % ] ( Turbulent Nose Cone ) center = 0.00398 2 1 . 2 [ % ] ( S h u l t z −Grunow ) t a i l = 0.00206 11.0 [%] −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Total = 0.01876 Drag c o u n t s = 187.6 P r o f i l e Drag Breakdown −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− F l i g h t Alt = 10.058 [ km ] 33000.[ feet ] Mach = 0.790 Fuselage = 0.01876 Wing = 0 . 0 0 4 9 9 Tail plane = 0.00129 Fin = 0 . 0 0 1 1 3 Nacelles = 0.00072 Pylons = 0 . 0 0 0 2 4 Winglets = 0.00005 Excrescence = 0.00125 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Total = 0.02870 Drag c o u n t s = 287.0

2.5.4

Propulsion Module

The FLIGHT program relies on an independent engine simulation module, that provides: Full-throttle engine performance: net thrust, fuel flow, specific fuel consumption, mass flow, nozzle speed and Mach number, temperature rise across fan, maximum combustor temperature and other parameters, as listed in the Nomenclature (page 65). Partial-throttle engine performance.

Figure 2.9 shows an example of engine charts that can be plotted from the output of the propulsion module.

2.5.5

Propeller Module

A separate, stand-alone, program can be provided, to analyse propeller performance, as discussed in Chapter 4. For the integrated version of the propeller code, the propeller is trimmed to required power or thrust, depending on the flight condition. Once the full trim is carried out, the aerodynamic loads are nominally “correct”, and the propeller noise model can be applied to predict both tonal and broadband noise for a fixed combination of source-receiver position. Details of the theoretical model (including the transonic aerodynamics) are given in Refs. 1;21 .


20

2 km 300

4 S/L

Net thrust, kN

6

200

8 10 12

100

14

0

200

400

600

800

1000

Mass flow rate, kg/s

Figure 2.9: Net thrust as function of mass flow rate for the GP-7200 operating at standard atmosphere. Altitudes are at 2,000 m interval from sea level.

2.5.6

Flight Mechanics Module

The module consists of two sub-modules: flight/mission planning and stability/control. The program provides the following outputs for mission analysis Iterative analysis of mission fuel, used fuel, reserve fuel, mission weight, ramp weight. Contingency fuel, based on 5 contingency scenarios. Environmental emissions.

The latter point consists in the following: the user is asked to enter passenger load (in percent) and atmospheric conditions. The program performs mission analysis at increasing ranges and provides on output a full account of exhaust emissions per passenger (pax), per-passenger/per nmile, etc. From the point of view of stability analysis, the program only calculates static stability conditions. In particular, the following options are available: Stall speed. Buffet Mach number and maneuver limits. Longitudinal trim. Main- and nose under-carriage load split at take-off and landing. Minimum control speed on ground, VMCG. Minimum control speed in air, VMCA. Limit rotation at take-off (tail strike). Limit bank angle at landing (wing strike).


2.5.7

21

Performance Module

The program provides the following outputs for performance analysis Aerodynamic performance charts (cruise and ground configuration) Engine performance charts. SAR performance charts (AEO and OEI, as required). See also Ref. 5;1 Control and stability charts. Take-off and landing charts (weight-altitude-temperature). Economic Mach number charts. Payload-range charts; constant BRGW charts.

Furthermore, it provides: Atmospheric properties at all altitudes (ISA and non ISA). Thermal loads on tyres during taxi, take-off and landing. Field performance: taxi-out, FAR balanced field length, All Engines Operating (AEO) and One Engine Inoperative (OEI) performance. Climb performance (fuel, time, distance to ICA for segment climb). Cruise performance, based on integration of point performance. Descent performance (conventional and continuous descent). Landing performance to a halt point. Flight trajectory, with 12 real-time output parameters. Long-range and maximum-range Mach numbers.

2.5.8

Optimisation Module

The optimisation module consists of two sub-modules: sensitivity analysis of system’s parameters and optimisation proper. The user can require a sensitivity analysis for the following cases: Specific air range (SAR). Constant Brake-release gross weight (BRGW). Wetted areas (components and grand total). Gross Take-off weight. On-board passenger services and baggage allowance.


22

Atmospheric conditions. Engine deterioration. Aerodynamic deterioration. Center of gravity position. Taxi-out time and roll-out distance. Direct Operating Costs (DOC)

The user can require optimization analysis for the following cases: Calculation of best Initial Cruise Altitude (ICA). Best climb procedure for given initial weight and final constraint on altitude and Mach number. Best cruise program (selection of flight levels, shift between flight levels, climb procedures between flight levels. Optimal cruise Mach number for a given mission range and payload. Optimal contingency fuel from 3 contingency alternatives. Economic Mach number for given mission range and payload. Approach and optimal guidance to ground level. Steep-descent and continuous descent procedures. Minimum-fuel steady-state turn. Fuel analysis of flight with en-route stop. Contrail avoidance trajectory.

Some of these procedures, such as the latter one, require additional data sets with reference to the atmospheric conditions along the flight path of the airplane.

2.5.9

Environmental Module

There are two sub-modules: engine emissions and aircraft noise. The environmental emissions are: Landing and take-off emissions (HC, CO, NOx). CO2 emissions (total, by segment, per passenger, per n-mile) Energy intensity for mission and by design (per n-mile, per passenger, etc.). Contrail factor.

Contrail analysis, altitude flexibility and trajectory options are provided on request. Figure 2.10 shows the analysis of carbon-dioxide emissions for a model Airbus A320-211 with CFM56 turbofan engines.


23

600

0.24

CO2/pax/nm, kg

CO2/pax CO2/pax/nm

0.2

200

0.16

CO2/pax, kg

400

0

1000

2000

0.12 3000

Stage length, n-miles

Figure 2.10: Carbon-dioxide emissions of an Airbus A320-211-CFM versus stage length at a fixed passenger load (75%), standard atmosphere.

2.5.10

Aircraft Noise Module

Some features of the noise modelling, transmission and propagation include the following: Jet-by-jet shielding. Doppler frequency correction. APU noise. Time shift due to speed of sound. Atmospheric absorption. Shear winds effects. Ground reflection and noise scattering. Arbitrary number of receiver points. Time-dependent noise footprints. Integral and time-dependent noise stacks (multiple aircraft)

The module performs the following calculations: Take-off trajectory, with receiver at FAR point. Landing trajectory, with receiver at FAR point. Sideline trajectory, with receiver at FAR point.


24

Arbitrary trajectory, with arbitrary position of receiver. Noise footprint (take-off, landing). Stacking patterns. Noise Directivity.

The stacking pattern option is only available on request, since it requires a complex set-up. The menu appears like this: Listing 2.5: Noise stacks options Options f o r M u l t i p l e A i r c r a f t Movements −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− S i n g l e Take−o f f AND Landing [1] M u l t i p l e Take−o f f AND Landings [2] Upper l e v e l [ any key ]

By default, some noise trajectories are self-generated. There is an option to read in externallygenerated trajectories, if they fulfill certain format requirements. The source components included in our analysis are: Propulsive Noise

- Fan - LP compressor - HP compressor - Combustor - Turbine - Nozzle/Jet - Jet shielding - APU noise (combustor and nozzle) Airframe Noise

- Wing, H-stabiliser, V-stabiliser - Flaps (inboard, outboard) - Slats (inboard, outboard) - Landing gear, including installation effects. Interference Noise

- Acoustic liners in the fan duct - Jet-by-Jet shielding - Fuselage shielding of engine and propeller noise


25

The [Noise-Propagation] sub-module includes all the routines that are used to calculate the external effects on the noise source. These are: atmospheric absorption, atmospheric thermophysics (temperature, density and humidity distributions), wind and turbulence, and ground effects (refraction, reflection). In terms of ground effects and lateral propagation, at least three models are used: 1.) Rasmussen-Almgren method, extended with numerical improvements for long-distance propagation; 2.) ray tracing methods; 3.) ANSI lateral propagation correction (optional). At present, a system analysis indicates that their inclusion would change the overall result by a value that is lower to the system’s inaccuracy. Validation of separate parts of the engine noise is available, and some is discussed later in this note. As mentioned earlier, there is a submodule that deals with signal analysis, to include all the propagation effects from source to receiver. The integral noise metrics provided include: EPNL (effective perceived noise level, dB); SEL (sound exposure level); PNLTM (maximum tone-corrected perceived noise level); LAmax (Acorrected maximum sound pressure level); TAUD (time-audible); awakening probability function. Time-dependent noise signals include the OASPL (overall sound pressure level), raw and A-weighted, for each individual noise component, for the propulsive contributions and for the airframe contributions.

Chapter 3

Guide to User Menu A number of user-menus are available to change some (not all) problem parameters. Not all options described are available in the demo version. We start from the top level and proceed toward the various sub-menus. When the aircraft is loaded, FLIGHT uses the database that accompanies the software. FLIGHT loads the engine model, the bitmap file, the aerodynamic derivatives, the aircraft design limitations, the engine design limitations and other ancillary data.

3.1

Top Level

The first operation to perform is to load an aircraft model. A large number of options is available, but the demo version contains one airplane model. Selection is done by entering an integer number. At that point the code loads the basic airplane data, constructs the geometry, calculates all the geometrical reference quantities. Then it loads the engine model and other data, and performs various parameter initialisations. In the process, it prints out several output files in the working directory. Once all this is done (it may take a few seconds to complete), the program is ready to go. Listing 3.1: Analysis Options A n a l y s i s Options ( Top l e v e l ) −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Performance Charts [1] Mission Analysis [2] A i r c r a f t Noise [3] Exhaust E m i s s i o n s [4] Flight Optimization [5] Maneuver A n a l y s i s [6] Trim A n a l y s i s [7] Direct Operating Costs [8] Utilities [9] E x i t / Quit [ any key ]

Note that some options are not activated. In particular, Option [9] (Utilities) is not available, and therefore it is not described.

26

3 User Guide

3.1.1

27

Performance Charts Sub-Menu

By choosing Option [1] in the top-level menu (Listing 3.1), the user is pointed to a sub-menu which shows the main performance charts that can be calculated with the FLIGHT code. These options should be self-evident. No propeller charts can be generated for a jet-powered airplane (Option [5] in Listing 3.2). Therefore, this option is automatically inactive for such an aircraft. For further details about Option [5] in Listing 3.2 see the description of the propeller code. Listing 3.2: Performance charts options Performance Charts −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Aerodynamics [1] S p e c i f i c Air Range [2] Engine E n v e l o p e s [3] F l i g h t Envelopes [4] Propeller WAT (AEO take−o f f ) Balanced F i e l d Length Payload−Range Economic Mach no . CG E f f e c t s B u f f e t Boundary Spec . E x c e s s Power Go−Around Charts Atm−Speed Charts Hol d i n g Speeds Max Descent Rates

[5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16]

V−n diagram Climb P o l a r Min . C o n t r o l Speed Gust Response L o n g i t u d i n a l dynamics A i r c r a f t volumes

[17] [18] [19] [20] [21] [22]

Upper l e v e l [ any key ]

[1] This option calculates the aerodynamic coefficients of the airplane, and determines aerodynamic charts as function of weight, altitude, centre of gravity position, etc. All the output files should be moved to the output sub-folder ./Charts. [2] This option generates specific-air-range charts, for both AEO and OEI conditions, over the full range of altitudes, weights and atmospheric conditions. [3] This option generates engine performance envelopes at the full range of atmospheric temperatures and altitudes, for specified flight Mach number; the Mach number is set by the user as a sub-option. [4] This option generates the 1-g flight envelopes of the aircraft, with limitations to stall, buffet, cabin-pressure altitude, etc. [5] This option generates the propeller charts; this can be avoided by also looking at the propeller charts available in the airplane model sub-folder.

3 User Guide

28

[6] This option generates weight-altitude-temperature charts for AEO take-off. After offering a number of default options, the user is prompted to a change of operational parameters. This is discussed separately in § 3.1.2. [7] This option calculates the balanced field length at one or several operation points. [8] This option generates the payload-range chart of the airplane, for a given set of input data, for which a sub-menu is presented to the user. [9] This option calculates the economic Mach number, and generates a chart of optimal/economical speeds as function of flight altitude. [10] This option performs sensitivity analysis of the centre of gravity position. [11] Buffet: This option generates the buffet boundary of the airplane. The results are only approximate. [12] SEP: This option generates charts of specific excess power in 1-g flight. [13] Go Around: This option calculates the go-around performance of the airplane in a variety of situations, including OEI. Several paramers can be changed by the user. [14] This option generates some charts containing relationships between CAS, TAS, EAS, Mach number and altitude. These charts are not dependent on the aircraft type. [15] Holding: This option calculates the holding charts at selected weights and hold altitudes. [16] This option attempts to calculate the maximum descent rate of the airplane with engine in idle mode (e.g. unpowered descent). [17] V-n: This option calculates the velocity-load-factor charts (V-n), at a specified gross weight. [18] This option calculates climb polar of the buffer airplane at selected weights and altitudes from MMO down to the stall speed. Steady state 1-g flight is assumed. [19] VMCA: this option calculates charts of steady-state lateral trim conditions, minimum control speed and stall speed at maximum (design) rudder deflection or maximum (design) aileron deflection. [20] Gust Response: this option calculates the airplane’s response to a cosine gust, as defined by FAR §25; it returns gust-response charts at selected altitudes at airspeeds VB, VC, VD. [21] Longitudinal Dynamics: This option is used to calculate the longitudinal dynamics of the airplane subject to a step input of the elevator. Both short-period and long-period of motion (phugoid) solutions are provided. All data, including undampted natural frequency and damping ratio are in the output files. [22] Volumes: This option allows the calculation of aircraft volumes (fuselage, wing, horizontal and vertical tail, etc.)

3 User Guide

3.1.2

29

The WAT Charts sub-menu

The Weight-Altitude-Temperature charts of a take-off are established from the performance submenu, which points to the following listing. Listing 3.3: Take-off options Change Take−o f f Data −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Runway c o n d i t i o n s [1] Tyre−runway s l i p r a t i o [2] Winds [3] Air Temperature [4] Runway g r a d i e n t , < 2% [5] Tentative f l a p s e t t i n g [6] CG−p o s i t i o n , %MAC [7] Execute C a l c u l a t i o n [0] Return

3.1.3

[ any key ]

Mission Analysis Sub-menu

This sub-menu appears as follows: Listing 3.4: Performance Charts A i r c r a f t M i s s i o n Options −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Fuel P l a n n i n g [1] A i r c r a f t Range [2] Matrix−Fuel−Plan Equal−Time P o i n t

[3] [4]

Upper l e v e l [ any key ]

More specifically, the operations carried out in this sub-menu are: 1. The option [Fuel Planning] deals with the calculation of the fuel required to perform a mission specified by payload, requested range and other details. The full specifications of the fuel planning are given by the following options: Listing 3.5: Mission Data M i s s i o n Data −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Required r a n g e [1] Required b ulk p a y l o a d [2] Required pax l o a d [3] Winds [4] Air t e m p e r a t u r e [5] R e l a t i v e Humidity [6] Aerodyn d e t e r i o r a t i o n [7] Engines d e t e r i o r a t i o n [8] Other F l i g h t Params [9] Execute Upper l e v e l [ any key ]

[0]

3 User Guide

30

The parameters in this menu should be self-explanatory, with the exception of Winds [3] and Other Flight Params [9]. With to point [3] in Listing 3.5, the user can change the wind speed and direction at take-off/departure, arrival/landing and cruise winds. Furthermore, there is an option to change the wind stability parameter, which determines the shape of the atmospheric boundary layer, and hence the speed of sound gradient, Listing 3.6. Listing 3.6: Updating Atmospheric Winds R e d e f i n e Atmospheric Wind P r o f i l e s −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Very u n s t a b l e [1] Moderately u n s t a b l e [2] Neutral [3] Slightly stable [4] Moderately u n s t a b l e [5] Very u n s t a b l e [6] Upper l e v e l [ any key ]

With reference to point [9] in Listing 3.5, there is a further set of option, Listing 3.7. Listing 3.7: Updating Mission Data Update M i s s i o n Data −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Continuous Descent Approach [1] Perfect Flight Trajectory [2] Taxi−i n time [3] Taxi−out time [4] Engine d e r a t i n g [5] Time−d e l a y , FLAP deployment [6] F i n a l approach g l i d e s l o p e [7] Runway s t a t e , both T .O. / Land [8] Airfield altitude [9] Turn i n climb−out [10] Flight Level Separation [11] Noise arrays extension [12] Upper l e v e l [ any key ]

Description of Listing 3.7 1. The first option commands the aircraft to perform a CDA from the final cruise altitude to about 1,500 feet above the airfield. 2. The second option, in addition to the CDA, includes a continuous climb to a cruise altitude which is unconstrained; the cruise itself is a continuous climb. 3. The third and fourth options establish the taxi-out and taxi-in times; local traffic conditions can be simulated with these parameters. 5. This option allow to simulate the effects of engine derating on take-off. 6. This option is used to study the effects on aircraft noise on approach and landing; the time delay is with respect to the deployment of the landing gear. 7. This option is used to calculate a final approach along a steep trajectory, γ > 3.

3 User Guide

31

8. This option is used to set the runway conditions to either dry (default) or wet. 9. Use this option to change the airfield altitude. Currently, we assume that departure and destination airfield are at the same altitude. 10. Use this option to set the change in heading required in a climb out. The altitude of the turn, as well as the normal load factors are set to default values (h = 400 m; n = 1.1) and cannot be changed at this time. 11. Use this option to change the default flight level separation. Possibilities are: 1,000 feet; 2,000 feet (default); 4,000 feet. 12. Use this option to increase the size of the noise arrays, to extend the flight trajectory. 2. The option [Aircraft Range] calculates the mission range for required payload and specified fuel load, in addition to similar parameters specified in [Fuel Planning]. Interactively, the user must type the passenger load, the bulk load and the fuel load. 3. The option [Matrix-Fuel-Plan] is a sensitivity analysis carried out with several parameters around a nominal value. Once the mission parameters have been fully specified, as in [Fuel Planning], the main parametric effects on the fuel consumptions are considered: a.) Change in air temperature b.) Error in the fuel load c.) Change of route d.) Effects of tail/head winds e.) Effects of bulk payload f.) Effect of passenger load g.) Effect of passenger services (including baggage). h.) Continuous descent from cruise altitude. 4. The option [Equal-Time Point] calculates the point in a mission that is the equal-time point, e.g. the time required to return to the origin is equal to the time to continue to the final destination. Note that this point is not equidistant from origing and destination.

3.1.4

Aircraft Noise Sub-menu

The prediction of aircraft noise is one of the main features of the code. Several examples of validation have been published 17;15;13;14 ;further developments will be available in the near future. Before describing the full options for the calculation of aircraft noise, it is necessary to clarify that a trajectory must be available. As explained further at a later point, the default trajectories printed out by the program are called iface noise*.out. The trajectories have the format shown in the box below. Each record must be separated by a semi-colon.

Flight_V 7.1.2. 20 Oct 2014, 12:19 # Landing Trajectory AIRCRAFTTYPE;ENGINETYPE Airbus A320-200-CFM ;CFM56-5C4P #

3 User Guide

32

AIRPORTNAME;RWYNAME;RWYLAT;RWYLON;RWYALT MAN;23R;0.0000;0.0000;70.0 # MICROLON_1;MICROLAT_1;MICROALT_1; 6036.0000; 0.0000; 62.0000; # DATE; Longitude; Latitude; Altitude; Theta; Phi; Psi; IAS; TAS; Groundspeed; Thrust; N1; fflow; Gear; SlatFlap;Weight;Temperature;Humid; pressure; Windspeed;Windirection

The first line indicates that the trajectory is self-generated. This line is missing for an external file. The second line shows that this is a landing trajectory. The lines below include the following: MICROLON, MICROLAT, MICROALT DATE Longitude, Latitude, Altitude Theta, Phi, Psi IAS; TAS; Groundspeed Thrust, N1 Gear; SlatFlap Weight Temperature, Humid, pressure Windspeed, Windirection

= = = = = = = = = =

coordinates of microphone/receiver flight time (various formats possible) coordinates of the airplane’s CG airplane attitude, heading, bank angles indicated, true and ground speeds net thrust and engine speed in percent landing gear position; slat/flap position all-up weight atmospheric quantities wind speed and wind direction

The microphone locations can be changed in a number of way. If two microphones are required, the line starting with MICROLON 1 is replaced by the following: MICROLON_1;MICROLAT_1;MICROALT_1;MICROLON_2;MICROLAT_2;MICROALT_2; 6036.0000; 0.0000; 62.0000; 5036.0000; 0.0000; 62.0000;

This command is recognised up to 4 microphones. However, for more than two microphones it is advisable to use the following alternative. ALLMICRO n x1 y1 x2 y2 .... xn yn

z1 z2

1 2

zn

n

where n denotes the number of microphones; each microphone line is established by (x, y, z)i , i = 1, · · · n, and a microphone number, which can be an arbitrary number (the microphone could be identified by any other integer). Th noise sub-menu appears as follows: Listing 3.8: Aircraft Noise Sub-Menu AIRCRAFT NOISE −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Take−o f f / Depar ture [1] A r r i v a l / Landing [2] S i d e l i n e a t ICAO/FAR p o i n t [3] Arbitrary trajectory [4] Noise Footprint [5] Stacking Patterns [6] Directivity Analysis [7] Options / U t i l i t i e s [8] Upper l e v e l [ any key ]

3 User Guide

33

More specifically, the operations carried out in this sub-menu are: 1. This option calculates the aircraft noise at a FAR/ICAO microphone, on the basis of an existing take-off/climb-out trajectory, previously calculated with a mission analysis. This trajectory is found in the ./Outputs/project airplane name/. sub-folder; the trajectory file is called iface noise takeoff.out, described above. 2. This option calculates the aircraft noise at a FAR/ICAO microphone, on the basis of an existing approach/landing trajectory, previously calculated with a mission analysis. This trajectory is found in the ./Outputs/project airplane name/. sub-folder; the trajectory file is called iface noise landing.out, described above. 3. This option calculates the aircraft noise at a FAR/ICAO microphone, on the basis of an existing approach/landing trajectory, previously calculated with a mission analysis. This trajectory is found in the ./Outputs/project airplane name/. sub-folder; the trajectory file is called iface noise sideline.out, described above. 4. This option calculates the aircraft noise at an arbitrary microphone, on the basis of an existing approach/landing trajectory, previously calculated with a mission analysis or prepared by other means. The trajectory file is found in the ./Outputs/project airplane name/. subfolder. 5. This option calculates the noise footprint, either on approach or take-off, on a carpet defined by the user, or on a carpet prepared by other means, who is prompted to Listing 3.9. Listing 3.9: Aircraft Noise Options Noise Footprint : S e l e c t t r a j e c t o r y −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− T a k e o f f / Depa rture [1] Approach / Landing [2] Departure + Landing [3] Ground P r o p e r t i e s [4] Upper l e v e l [ any key ]

There is the possibility of changing the ground properties (for fixed ground impedance), by selecting Option [4] in Listing 3.9, which must be done before choosing the trajectory, Options [1], [2], [3]. The ground relection properties are for: [1] snow; [2] grass; [3] sand; [4] wet/water; [5] tarmac/concrete. The atmospheric properties can be: [1] still air; [2] nominally still air; [3] moderate; [4] turbulent. This is achieved via sub-menus not shown here. Upon choosing one of the options in Listing 3.9, the user is prompted to Listing 3.10. Listing 3.10: Noise Footprint Options N o i s e F o o t p r i n t : S e l e c t Grid −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− S e l f −g e n e r a t e g r i d ( d e f a u l t ) [1] Read e x t e r n a l g r i d ( a i r f i e l d ) [2] Upper l e v e l [ any key ]

3 User Guide

34

If Option [1] is selected, the user must enter: 1.) x-size of the noise carpet (parallel to flight direction); 2.) y-size of the noise carpet (normal to flight direction). Then the user is prompted to a choice of grid resolutions: coarse, medium (recommended) and fine (CPU intensive). The actual number of grid points cannot be changed. There is one further sub-option on [1]: to calculate a noise footprint on a self-adaptive grid. The grid points are rearranged in the lateral direction so as to cluster closer to the large gradients of a specified noise metric. The calculations can be time consuming, because they require a preliminary calculation on a very coarse grid to establish the noise gradients. Before starting the computations, one more decision has to be made: whether to ignore atmospheric winds (Yes/No). In the affirmative, some execution speed can be gained. CPUintensive means at least overnight calculations in absence of atmospheric winds, and weekend in the presence of strong winds. If Option [2] is selected, the user must enter the file name of the grid, residing in the working directory. This file can be an ASCII data file or a csv-file (comma-separated). Grid coordinates can be in a local reference system (units: metres), or GPS coordinates. An example of this data file is shown below. GPS conversion 53.3615 -2.259 78 invert rotate 106 53

YES

NO YES

! ! ! ! ! ! !

LATITUDE LONGITUDE SURFACE 53.28050015 -2.370239699 G 53.28155556 -2.368056271 G 53.28261096 -2.365872843 G 53.28366637 -2.363689415 G 53.28472178 -2.361505987 G 53.28577719 -2.359322559 G 53.28683260 -2.357139132 F 53.28788801 -2.354955704 G

data are in GPS coordinates conversion to local refererence system required if YES coordinates of reference point at airfield if YES airport altitude [m] inversion of matrix required if YES align grid along long axis nxgrid nygrid

A B C F G S T W

Legend Asphalt (dry) Built-up area (dry) Concrete (dry) Forest (dry) Grass (dry) Snow (wet?) Tarmac (dry) Water (wet)

Figure 3.1 shows selected points at London Heathrow. Latitude and longitude coordinates are derived from maps such as these and ground characteristics are associated, as described. 6. The stacking pattern option works only with one airplane type. There can be a selection of approach and take-off trajectories for the same airplane, as well as the time separation between flights (this separation is given in seconds). On output, the program produces *.avi files can than be played to visualise the behaviour of the OASPL. Listing 3.11: Options for Calculating footprints from multiple movements Options f o r M u l t i p l e A i r c r a f t Movements −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− S i n g l e Take−o f f AND Landing [1] M u l t i p l e Take−o f f AND Landings [2] Upper l e v e l [ any key ]

3 User Guide

35

Figure 3.1: Model for a London Heathrow (LHR) grid for noise footprint calculations. The second sub-option requires to chose between raw OASPL and A-weighted OASPL. Only one noise metric is processed due to the large file size that is generated by this operation. 7. This option calculates the noise directivity around the airplane, with the airplane airborne or at the brake on the ground. In the latter case, only engine noise is calculated. The program requests the name of a data file, which contains the essential data for the calculation. These data are: Listing 3.12: Template of directivity file LATERAL

d i r e c t i v i t y ty pe

Unit

! LATERAL/POLAR/FRONTAL o n l y

200. −5.

RADIUS z below CG

[m] [m]

! r a d i u s o f microphones c e n t e r e d a t CG ! p o s i t i o n o f r e f . c i r c l e above / below CG

457 . 1.9 0.0 0.0 140.3

Altitude Theta Phi Psi KTAS

[m] [ degs ] [ degs ] [ degs ] [ kt ]

! ! ! ! !

1 5 55.9 0.29879 0.0 0.0 70.0 0. 50000.

LGear iSlatFlap N%1 fflow WindSpeed WindDirection Relative humidity dTemp mass

! ! [%] ! [ kg / s ] ! [m/ s ] ! [ degs ] ! [%] ! [K] ! [ kg ] !

f l i g h t a l t i t u d e ( ground a t z = 0 ) pitch attitude bank a t t i t u d e / a n g l e heading t r u e a i r speed , k n o t s landing gear p o s i t i o n : 1 = deployed Flap / S l a t s e t t i n g = 0 , 1 , 2 , 3 , . . . e n g i n e rpm ( unused ; p r e f e r s f u e l f l o w ) f u e l flow ( a l l engines ) wind s p e e d wind d i r e c t i o n r e l a t i v e humidity o f a i r dTemp = 0 −> s t a n d a r d day a l l −up mass ( c u r r e n t l y unused )

The program calculates the polar directivity (on a vertical plane) and the lateral directivity (on a horizontal plane), according to the first parameter, which can be POLAR or LATERAL or FRONTAL. An error message is issued otherwise. The program returns the OASPL(dB), and the noise contribution from all active components.

3 User Guide

36

The fuel flow is intended for all engines. Normally, calculations are done in the absence of wind. The relative humidity has very limited effects over short distances. 8. The final Option [8] in Listing 3.8 allows the user to change some problem parameters, specifically the ground properties (resistivity, inverse depth etc.); it also allows to set the “noise sensitivity” analysis, which is based on perturbations of key design and operational parameters. If this option is set, when returning to the main noise menu (Listing 3.8), the take-off [1] and landing [2] calculations will use a perturbation data file in the ./Airplanes sub-folder. These calculations include sensitivities on about 40 parameters, but are not offered in the demo version. The full menu of user-options is shown in Listing 3.13. The acoustic liners boundary layer calculation is set to false by default. This can be toggled by choosing [5] in Listing 3.13. Listing 3.13: Noise sub-options menu, propagation models N o i s e Options , U t i l i t i e s and D e f a u l t s −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Parameter S e n s i t i v i t y A n a l y s i s [ 1 ] Ground−Turbulence P r o p e r t i e s [2] I n c l u d e background N o i s e [3] Change N o i s e P r o p a g a t i o n Model [ 4 ] Change N o i s e S o u r c e Models [5] A c o u s t i c L i n e r Boundary Layer [6] Convert N o i s e T r a j e c t o r y t o 2D [ 7 ] R e f i n e N o i s e Carpet / F o o t p r i n t [8] Toggle topography e f f e c t s [9] Generate Fly−o v e r t r a j e c t o r y [10]

The background noise is included when toggling option [3]. The program points a question to the user to change the background noise to a specified spectrum, which must be read from a data file in the working directory. This file contains two columns: frequency and noise level. The noise level can be A-weighted or not; the program will sort out the sums after the user provides the correct information. It is possible to change some noise models with option [5], although in fact there are some limitations and the best results are obtained with default models. Considerable work is still needed in this area. Toggling the acoustic liner boundary layer, option [6], forces more demands on the computational efforts, and the program can be sensibly slower. Note that the background noise is treated as an additional noise source that is added at the end. This implies that the various source contributions are not affected, but the final sum and the integral noise metrics are affected by the background noise. The noise propagation models are shown in Listing 3.14. This menu is accessed from Option [8]. Listing 3.14: Nose sub-options menu, propagation models N o i s e P r o p a g a t i o n Options −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Rasmussen / Almgren method , DEFAULT [ 1 ] ANSI/SAE AIR 5 6 6 2 , l a t e r a l propag . [ 2 ] Ray t r a c i n g method [3] Upper l e v e l [ any key ]

3 User Guide

3.1.5

37

Propeller Noise

The case of propeller-driven airplane is computationally more elaborate, since it relies of an long sequence of events involving flight mechanic calculations. In brief, at each time step, the propeller is trimmed to match the flight mechanics equations, and thus will have a required power or thrust. These parameters form the basis of a propeller trim, which then provides the aerodynamic loads that are finally used by the acoustic solver. An interface file is required; this is called proponoise.iface, an example of which is shown below. This file is automatically generated. "Dash8_Q400" "R408" 0.1937 "landing" 7894.1000 6420.4426 0.9986 65.7386 112.0125 0.1000E-02 .true. END

3.1.6

0.0000 0.0000 0.0000 0.0000

113.4400 71.2000 -0.0524 -3.4500

Airplane name Propeller name Flight Mach number Flight condition Source Position in ground reference (x,y,z) [m] Receiver Position in ground reference (x,y,z) [m] Unit vector parallel to propeller shaft Vector velocity in ground reference [m/s] Required shaft power [kW] Max Tolerance on propeller trim conditions Propeller trim required

Noise Calculations Outputs

On output, this module provides a very detailed analysis of the airplane performance. There are at least three types of outputs: 1. Noise breakdown files: these are printed for each ground microphone and for each flight trajectory. The output file contains the main flight parameters as well as the following noise metrics: OASPL (overal sound pressure level); OASPLa (airframe OASPL); OASPLe (engine OASPL), LA[dBA] (A-weighted OASPL), PNL (perceived noise level), PNLT (tone-corrected perceived noise level), Loud (noise loudness). 2. Noise trajectory files: in addition to the basic flight parameters, these files include the engine state over the full trajectory. 3. Noise report files: these reports include the spectral components of each contribution (split between propulsive and non propulsive), as well as the key integral noise metrics: EPNL(dB), SEL(dB), LAeqT(dB), PNLTM(dB), TAUD(dBA). The noise breakdown output files contain the parameters in Listing 3.15. Listing 3.15: Output data in noise breakdown files a. b. c. d.

SRCt [ s ] x [ km ] r [ km ] LGear

RECt [ s ] y [ km ] theta iSF

e. f. g.

Wing FANi APUC

h.

OASPL

s [ km ] KTAS

h [ km ]

h[ kft ]

HSTAB FANe APUJ

VSTAB FAN

SLAT LPC

FLAP HPC

OASPLa

OASPLe

eCORE

PNL[ dB ] PNLT[ dBA ]

NLG COMB

MLG HPT

LPT

JET

LA [ dBA ] Loud [ dBA ]

Although all these parameters are on a single row, here they are discussed on the basis of their different categories:

3 User Guide

38

a.) Flight time at source and receiver. b.) Aircraft position. c.) Distance, emission angle and true air speed. d.) Aircraft configuration. e.) Noise contributions from airframe. f.) Noise contributions from engine. g.) Noise contributions from APU. h.) Noise metrics. (see also nomenclature)

3.1.7

Exhaust Emissions Sub-Menu

The fourth option in the main menu, page 26, is a call to the exhaust emissions analysis. This call points to the following set of sub-options. Listing 3.16: Aircraft Emissions Sub-Menu A i r c r a f t E m i s s i o n s Deck −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Exhaust E m i s s i o n s vs r a n g e [ 1 ] Contrail Analysis [2] Upper l e v e l [ any key ]

More specifically, the operations carried out in this sub-menu are: 1. This option allows the calculation of aircraft emissions corresponding to a given payload and passenger load; the range is swept from 200-300 n-miles to the design range. The emissions (CO2, CO, NOx, HC, etc) are given as function of range, per pax, per seat, etc. A sub-menu is available to input key operational requirements. 2. This option allows the simulation of aircraft contrails and a number of related emissions characteristics; this option is not available in the DEMO version.

3.1.8

Flight Optimisation Sub-menu

There is a limited number of options concerning optimisation of flight operations. The current version of FLIGHT has the features in listing 3.17. Listing 3.17: Flight Optimisation Sub-Menu O p t i m i s a t i o n Deck −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Minimum Climb−Fuel [1] Optimum Climb between F l i g h t L e v e l s [2] Fuel Tankering A n a l y s i s [3] Upper l e v e l [ any key ]

1. This option estimates the minimum climb fuel to a specified initial cruise altitude, for specified gross take-off weight. 2. This option estimates the optimum climb rate between two flight levels at cruise. 3. This option estimates the optimum tanker fuel for a specified mission.

3 User Guide

3.1.9

39

Manoeuvre Analysis Sub-menu

In the current version of the software there is only one option here: the calculation of aircraft landing in a downburst. An option menu appears to set the main characteristics of the downburst wind. The data required to enter include: a.) height of the cloud base above the airfield; b.) diameter of the downburst; c.) vertical wind speed at the centre of the downburst. If a flight manoeuvre inside a downburst is required, the program requests the minimum distance from the core of the downburst, then it automatically sets the airplane on a flight path through the downburst starting from an altitude of 1,500 feet AGL (Above Ground Level).

3.1.10

Trim Analysis Sub-menu

The aircraft trim options include the minimum control speed in air (VMCA) and the minimum control speed on the ground. An option menu appears to set the main characteristics to calculate the minimum control speed. These options are not active in the DEMO version. Listing 3.18: Aircraft Trim Sub-Menu A i r c r a f t Trim Deck −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Minimum C o n t r o l Speed i n Air , VMCA [1] Minimum C o n t r o l Speed on Ground , VMCG [2] Upper l e v e l [ any key ]

3.1.11

Direct Operating Costs Sub-Menu

This option requires the user to provide the name of an input file with the case data; this file must reside in the working directory, where the executable runs. The reason why a file name is required at this stage is that the number of input parameters can be excessive (at least 36 parameters), and trying to select these data through a simple user-input can be a frustrating experience. For convenience, we report below a template of such a file, with the description of the case data. This file must reside in the airplane model sub-folder. If this file is provided with the software, do not change its name. The program does not verify these numerical data, except the number of cycles required for stage length, block time and any negative entry; all data must be consistent and reasonable. If something is wrong on input, the program will report the line number relative to the last record read successfully. For example if last record = currency, there must be something wrong in the aircraft price data (one line below). Listing 3.19: DOC File Notes (refer to Listing 3.20) a. b. c. d. e.

man hour i n f l a t i o n i s t h e same a s ” c r e w p r i c e i n f l a t i o n ” l a b o u r r a t e i n f l a t i o n i s t h e same a s ” c r e w p r i c e i n f l a t i o n ” a l l o t h e r c o s t s ( s p a r e p a r t s , e t c . ) a r e i n f l a t e d by t h e same amount i f no OIL SHOCK i s e x p e c t e d , assume 1 . 0 ; t h e y e a r ( next r e c o r d ) i s i g n o r e d number o f c y c l e s i s t e n t a t i v e ; FLIGHT w i l l make a b e t t e r e s t i m a t e ; may o v e r r i d e data above f . i f you change t h e s t a g e l e n g t h and / o r t h e bulk cargo , you must r e p e a t m i s s i o n c a l c u l a t i o n , b e c a u s e f u e l burn and b l o c k time w i l l be d i f f e r e n t g . t h e o v e r r i d e parameter must be t r u e o r f a l s e . E r r o r i s e n c o u n t e r e d o t h e r w i s e ; t h i s parameter i s o v e r r i d d e n i f t h e number o f c y c l e s i s not a c h i e v a b l e . h : commuter s e r v i c e (X < 250 n−m i l e s ) ; i n t e r n a t i o n a l ( 2 5 0 < X < 2 5 0 0 ) ; i n t e r c o n t i n e n t a l (X > 2 5 0 0 )

3 User Guide

40 Listing 3.20: DOC File (template)

”A. F i l i p p o n e , on 15 August 2 0 1 2 ; P r o j e c t = G550 DOC” ”G550” a i r p l a n e name ” Dollars ” 47 d6 0.67 1.0 25. 2 1.2 0.5 0.5 0.1 20. 85. 70. 4.0 10 55000. 25000. 2. 80.

! don ’ t f o r g e t t i t l e

currency

( data below i n D o l l a r s )

aircraft price f u e l p r i c e n o w ( f u e l p r i c e TODAY) fuel price inflation f u e l p r i c e h i k e on s p e c i f i e d y e a r : OIL SHOCK y e a r a t which OIL SHOCK i s e x p e c t e d i n s u r a n c e , based on a i r c r a f t a c t u a l v a l u e

( i n above c u r r e n c y ) ( p e r kg ) (% p e r year , AVERAGE) (%) (% p e r y e a r )

s p a r e s p r i c e 1 ( a i r f r a m e , l a n d i n g gear , t y r e s ) (% on Year 1 ) s p a r e s p r i c e 2 ( e n g i n e , APU, l u b r i c a n t s ) : (% on Year 1 ) s p a r e s p r i c e 3 ( a v i o n i c s / s y s t e m s / p a x s e r v i c e s ) (% on Year 1 ) life time d e p r e c i a t i o n o v e r l i f e −time financing interest rate y e a r s o f mortgage ( i n t e g e r number )

(% o f i n i t i a l c o s t ) (% o f i n i t i a l c o s t ) (%)

crew price1 crew price2 crew price off station

( f u l l time / p i l o t / y e a r ) ( f u l l time / s t a f f / y e a r ) (% p e r y e a r ) ( per person / night )

, pilots , f l i g h t attendants inflation p r i c e ( hotels , etc )

75. 40. 65.

l a b o u r r a t e 1 , powerplant l a b o u r r a t e 2 , in−house maintenance l a b o u r r a t e 3 , c o n t r a c t e d out

(man−hour ) (man−hour ) (man−hour )

50. 50. 50.

man hour1 , p o w e r p l a n t man hour2 , in−house man hour3 , c o n t r a c t e d out

( per 1 ,000 c y c l e s ) ( per 1 ,000 c y c l e s ) ( per 1 ,000 c y c l e s )

landing charges , airport fees ground h a n d l i n g c o s t s recurrent training costs f l i g h t s e r v i c e c o s t s : c a t e r i n g , m a rk e t i ng

( p e r movement ) ( p e r movement ) ( f l i g h t crew / y e a r ) ( pax / f l i g h t ; y e a r 1 )

300. 200. 50000. 50.

600 cycles ( c y c l e s / year ) ” i n t e r c o n t i n e n t a l ” s e r v i c e typ e see note [ h ] . true . o v e r r i d e ” c y c l e s ” i f t r u e ; keep above v a l u e i f . f a l s e . 4500. s t a g e l e n g t h , n−m i l e s ( average ) 70. average l o a d f a c t o r ( pax / s e a t s ) 16200. 670. 100. 5.25

m i s s i o n f u e l burn * P r e v i o u s l y c a l c u l a t e d * b l o c k time * P r e v i o u s l y c a l c u l a t e d *

( kg ) ( min )

cargo / f r e i g h t cargo price

( kg / f l i g h t ) * Unused ( c u r r e n c y / kg ) * Unused

Do not swap lines: The program will not understand it. The program cannot be responsible for silly entries.

3 User Guide

3.2

41

Batch Jobs (Linux/Unix Version)

Some computations require too much time to be monitored on screen. Therefore, we have developed a procedure to launch batch jobs, without user interface. The program reads a file “batch file.txt” in the working folder. At present there are three types of batch jobs. These Noise Footprints. These may require several CPU days if the grid is made of thousands of points, atmospheric wind effects are requested, the ground has a mixed impedance, as in Figure 3.2. In this instance, the program is required to read an input file, in the working folder, containing the basic commands to execute the job. An example of such file is described in Listing 3.21.

3000

sigmae: 5.0E+05 1.0E+06 1.5E+06 2.0E+06 2.5E+06 3.0E+06 3.5E+06 4.0

y[m]

2000 1000 0 -1000 -2000 -5000

0

x[m]

5000

Figure 3.2: Airport model with variable ground properties; ground impedance shown here.

Listing 3.21: Batch job file for noise footprints #

Batch f i l e f o r f o o t p r i n t c a l c u l a t i o n : B747−400 ”B747 −400” a i r p l a n e name ” turbofan ” e n g i n e type 12 a i r p l a n e index ” landing ” t r a j e c t o r y t ype ; u s e s d e f a u l t f i l e i n . / P r o j e c t s / A i r p l a n e ” external ” g r i d typ e ” Heathrow . c s v ” g r i d f i l e name . true . i g n o r e a t m o s p h e r i c winds i f t h i s f l a g i s t r u e

Noise Sensitivity Analysis. As in the previous case, several hours may be required to run sensitivity cases to uncertain parameters, on single and multiple microphones. Currently, we use in excess of 50 parameters, implying over 100 runs for a single microphone/trajectory combination. The computations are more aggressive in the case of turboprop airplanes, since these airplanes require an inner loop to provide the trim equations for the propeller and the flight mechanics. An example of such file is described in Listing 3.22. Listing 3.22: Batch job file for noise sensitivity analysis #

Batch f i l e Dash8−Q400 ; DO NOT SWAP LINES ; code w i l l not r e c o g n i s e t h i s f i l e ”noise sensitivity” type o f c a l c u l a t i o n r e q u e s t e d ” Dash8 Q400 ” a i r p l a n e name ” turboprop ” e n g i n e ty pe 2 a i r p l a n e i n d e x ; c u r r e n t l y ** hard−coded ** ” landing ” t r a j e c t o r y type ; u s e s d e f a u l i n . / P r o j e c t s / A i r p l a n e ” external ” t r a j e c t o r y type type ” i f a c e n o i s e l a n d i n g . out ” t r a j e c t o r y f i l e name

3 User Guide

42

Noise Calculations. This case is not computationally demanding. However, it is useful to run parametric analyses on the trajectory, for example in trajectory optimisation. In this case, the FLIGHT program runs as a tool-box for calculating the noise on a specified trajectory. The configuration file, called “batch file.txt” is described in Listing 3.23. Listing 3.23: Batch job file for noise calculations #

Batch f i l e f o r A320 200 ; DO NOT SWAP LINES ; code w i l l not r e c o g n i s e t h i s f i l e ’ noise ’ typ e o f c a l c u l a t i o n r e q u i r e d ; code r e c o g n i s e s t h i s keyword ’ A320 200 ’ a i r p l a n e name ’ turbofan ’ e n g i n e type 3 a i r p l a n e i n d e x ; t h i s i s c u r r e n t l y ** hard−coded ** ’ landing ’ t r a j e c t o r y ty pe : l a n d i n g o r t a k e o f f ’ default ’ p a r s e s d e f a u l t f i l e i n . / P r o j e c t s / Airplane name / Outputs / . true . i g n o r e a t m o s p h e r i c winds i f t h i s f l a g i s t r u e

Trajectory optimisation is to be carried out by using the standard trajectory interface. It is likely that the engine data are not available in such a context; if the engine data are indeed not available, the respective columns will be filled with zeroes or negative numbers. The program runs a check to verify that the engine rpm (N%1) is always positive. If N%1 < 0 in at least one instance, the program interprets this case as one of trajectory optimisation with missing engine data. The next step is to provide these data. This is done by “flying” the trajectory. Specifically, the program attempts to run the specified trajectory and matches the engine state (Wf6, N%1) to the state array {X(t), V (t), α(t), β(t), ϕ(t)}

(3.1)

On output, this run generates a file cost functions.txt in the working directory. This file contains selected noise metrics and exhaust emissions, which can be used, in isolation or in combination, to determine a cost function for trajectory optimisation. An example of such output is given below. Data are printed as e16.8 to allow for further numerical analysis without loss of precision. Listing 3.24: Output of batch job file for noise calculations (cost functions.txt). # P r e d i c t e d e n v i r o n m e n t a l e m i s s i o n s ; g e n e r a t e d by FLIGHT V. 7 . 4 . 7 # SECTION 1 : N o i s e E m i s s i o n s 0 . 1 3 5 3 3 6 9 0E+03 F l i g h t time [ s ] 0 . 9 0 6 9 3 1 7 1E+02 EPNL[ dB ] 0 . 8 5 6 7 0 2 4 6E+02 SEL [ dB ] 0 . 6 5 4 9 2 6 7 9E+02 LAeqT [ dBA ] 0 . 8 4 1 9 2 4 9 3E+02 SPLmax [ dB ] 0 . 8 0 4 4 8 4 3 9E+02 LAmax [ dBA ] 0 . 8 3 8 9 4 5 7 1E+02 SPLfmax [ dBA ] 0 . 7 7 8 3 9 5 7 3E+02 SPLemax [ dBA ] #

SECTION 2 : Exhaust E m i s s i o n s 0 . 2 1 6 2 0 4 7 9E+02 Fuel burn [ kg ] , below 3 , 0 0 0 f e e t AGL 0 . 6 8 2 3 4 2 3 1E+02 CO2 [ kg ] below 3 , 0 0 0 f e e t AGL 0 . 7 5 0 0 8 6 7 1E+03 CO [ g r ] below 3 , 0 0 0 f e e t AGL 0 . 4 5 2 4 4 7 7 9E+03 NOx[ g r ] below 3 , 0 0 0 f e e t AGL 0 . 4 9 5 6 1 7 5 7E+02 HC [ g r ] below 3 , 0 0 0 f e e t AGL

3 User Guide

3.3

43

Other Tools

To carry out some of the analyses discussed in this reports, we have developed additional tools that operate on top of the main program or as a stand-alone utilities. One of these is a map tool that is used to generate detailed airport maps — more detailed than the ones shown in Figure 3.2. These detailed maps, which can have a grid resolution of 30 m, or less, with altitude resolution of the order of 1 m, are then transformed into useful maps for noise footprint calculations. Typical operations include: Choice of grid resolution, to reduce the amount of grid points. Association of a ground impedance value to each ground type (11 ground types available). Removal of grid points on bodies of water (sea, lakes, reservoirs) so save computing time. Removal of grid points in areas other than built-up areas, to reduce the calculation effort. Grid partition for multiple processor calculation. Syncrhonisation of the map with the flight trajectories. Ground statistics and computing time forecasts.

The core of this tool is written in Matlab, and the pre-processor is written in Fortran. An example of pre-processing is shown in Figure 3.3, which refers to London Heathrow (LHR) airport, with an Airbus A380-862 on arrival. The vertical scale is exhaggerated to make the plot readable. The airplane itself is off-scale. Six map partitions are shown in this case. The noise level can be calculated separately on each partition.

500

2500

900 600 N

300 0

5000

10000 M25

[m ]

15000 Figure 3.3: Map tool pre-processor for noise footprint calculations. This case shows LHR airport with a landing/arrival of an Airbus A380-862.

3 User Guide

3.3.1

44

How to Restart a Footprint Analysis

Noise footprint calculations are computationally very demanding. As a rule of thumb, we have: Twin-engine turbofan airplane: 25-30 s/grid point, depending on hardware platform Four-engine turbofan airplane: 30-35 s/grid point, depending on hardware platform Turboprop airplane, 2-3 minutes/grid point

The turboprop airplane case has not been numerically optimised, something that will be done in the future, with the goal of reducing the computing time to a similar value to that of the turbofan airplane. The data indicated refer to absence of winds. The presence of strong winds, especially if sideways, increases enormously these computing times, and general guidance cannot be given in this instance. Restart Procedure If the job has been killed before completion, it can be restarted following the same steps. The program is able to identify the existence of a footprint output in the working folder and asks the user whether to restart or not. In the affirmative, the data are appended to the existing file and restarting is done from the last grid point, identified automatically. In the other case, the existing footprint output file is overwritten and computations start afresh. The user can see where computations have been restarted, since each restart prints out a comment line such as: ------- Restarting from grid point 159 on 11 August 2015; time 9:15

3.3.2

Aerodynamic Tools

The AeroTool is a program that returns the aerodynamic coefficients of the airplane at the specified flight conditions. This tools runs without user I/O. It reads configuration file aerotool.cfg in the ./Data sub-folder and prints-out the output aerotool.out in the working folder. The configuration file is as follows: Listing 3.25: Typical configuration file aerotool.cfg. # This i s t h e c o n f i g u r a t i o n f i l e f o r t h e AeroTool # L i n e s s t a r t i n g with hash−t a g a r e comments and a r e i g n o r e d # Command l i n e s below cannot be swapped # omputer code w i l l not r e c o g n i s e swapped e n t r i e s ” Airbus A320 200 ” ! a i r p l a n e name 70 d3 ! a i r p l a n e mass [ kg ] 1000.0 ! f l i g h t a l t i t u d e above mean s e a l e v e l 0.30 ! t r u e Mach number 0.0 ! change i n a i r t e m p e r a t u r e o v e r / below ISA a t f l i g h t a l t i t u d e 1.0 ! a t t i t u d e angle , degrees 1.0 ! bank a n g l e , d e g r e e s 1 ! Landing g e a r : iLG = 0 ( r e t r a c t e d ) ; o t h e r number ( d e p l o y e d ) 0 ! s l a t / f l a p : iSF = 0 ( r e t r a c t e d ) ; o t h e r i n t e g e r ( d e p l o y e d )

The configuration file requires the airplane name (it must be recognised), its all-up weight, the flight altitude, the true Mach number, the change in air temperature, the attitude and the bank angles; the landing gear configuration (retracted or deployed) and the high-lift configuration (retracted or deployed). The latter entries must be integer numbers.

3 User Guide

45

Typical run time of this tool is about 2 seconds. On output, it provides the CL and CD of the airplane at the requested configuration and operational environment.

3.3.3

Propulsion Tools

The EngineTool is a program that returns the net thrust or net shaft power of the airplane at the specified flight conditions. This tools runs without user I/O. It reads configuration file enginetool.cfg in the ./Data sub-folder and prints-out the output enginetool.out in the working folder. The configuration file is as follows: Listing 3.26: Typical configuration file enginetool.cfg. # This i s t h e c o n f i g u r a t i o n f i l e f o r t h e AeroTool # L i n e s s t a r t i n g with hash−t a g a r e comments and a r e i g n o r e d # Command l i n e s below cannot be swapped ; code w i l l not r e c o g n i s e swapped e n t r i e s ” Airbus A320 200 ” ! a i r p l a n e name 1000.0 ! f l i g h t a l t i t u d e above mean s e a l e v e l 0.30 ! t r u e Mach number 80.0 ! N1ggp−req , e n g i n e rpm , t y p i c a l l y 25 < N1ggp−r e q < 103 0.0 ! a i r temperature at f l i g h t a l t i t u d e

The configuration file requires the airplane name (it must be recognised), the flight altitude, the true Mach number, the change in air temperature, and the gas turbine rpm, called N %1 at the requested engine state. Typically, this is a number 25% ¡ N%1 ¡ 104%, which can be associated to a throttle setting. Typical run time of this tool is about 0.25 seconds. On output, it provides the net thrust FN of one engine of the airplane at the operational environment. The EngineTool and the AeroTool can be used in combination to solve general flight mechanics equations.

3.4

Error Messages

There are several types of errors. They should all be described as a screen message with the address where the error has occurred. All errors, with few exceptions, have the following message: [Subroutine_name]: error message ** Program Halted **

The information contains the location in the source code where the error has occurred and some information that may be helpful in fixing the error. There are over 420 recorded possible instances of errors. If you think that the error is a programming bug, please report the problem to the author.

Chapter 4

Guide to Propeller Code The propeller module is provided as two independent codes: propnoise, used by FLIGHT on all turboprop aircraft, and propeller, which is a stand-alone user-input code with several performance options, some of which are discussed in this chapter.

4.1

User Menu

The first operation to perform is to load a propeller model. A large number of options is available, but the demo version contains one propeller model. Selection is done by entering an integer number. At that point the code loads the basic propeller data, constructs the geometry, calculates all the geometrical reference quantities. In some cases it loads the airplane model and other data, and performs various parameter initialisations. In the process, it prints out several output files in the working directory. Once all this is done, the program is ready to go. The options available are presented in Listing 4.1. Listing 4.1: Propeller Analysis Options P r o p e l l e r A n a l y s i s / Design Options −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− P r o p e l l e r Geometry [0] Performance a t Design P o i n t Performance i n O b l i q u e F l i g h t Performance Charts P r o p e l l e r Design P r o p e l l e r Trim P r o p e l l e r Noise Performance o f Ducted Prop S e n s i t i v i t y Analysis

[1] [2] [3] [4] [5] [6] [7] [8]

E x i t / Quit [ any key ]

Note that some options are not activated. In particular, Option [7] (ducted propeller) and [8] (sensitivity analysis) are not available in the demo version. 0. The first option [0] calculates the blades, propeller and hub geometry and produces output files that can be visualised (see for example Figure 4.1). This option also performs a number of aerodynamic and structural ancillary calculations. No performance calculations are carried out.

46

4 Propeller Module

47

1

0

-1

2

0

z, m

1

-1

-2

Figure 4.1: Model of the Hamilton-Sundstrand F568 six-bladed propeller in the FLIGHT program.

1. This option [1] commands the calculation of the propeller performance at the design point, which is defined in the propeller definition files. 2. This option [2] points to a sub-menu, in which the user must insert data corresponding to a non axial flight. The program then computes the aero-propulsive performance at this point and prints out various data, including loads distributions on the propeller disk. The sub-menu is: 3. This option [3] prompts to the calculation of a variety of performance charts, which include: • Propeller charts for FLIGHT-propnoise interface • Effect of collective pitch • Effect of propeller rpm • Effect of flight altitude 4. This option [4] calculates the propeller performance at the design point. Listing 4.2: Non-axial flow performance Non A x i a l F l i g h t Options −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− S i n g l e −P o i n t A n a l y s i s [1] Yaw sweep [2] P i t c h sweep [ 3 ] E x i t / Return [ any key ]

5. This option [5] requires the user to input the required power; the code will attempt to trim the propeller at the prevailing flight condition (speed, altitude) and the specified power.

4 Propeller Module

48

Input data must be sensible, otherwise the code will not converge. In general convergence is good at high power settings, less so at low power settings. The results include the propulsive efficiency, the thrust and power coefficients, the thrust, power and torque. 6. This option [6] calculates the propeller noise at the default operational conditions. One such default listing is given below (Listing 4.3). Use the numbered options to change the operational conditions. Listing 4.3: Operational conditions for propeller noise (default) P r o p e l l e r N o i s e Setup . D e f a u l t v a l u e s shown . Use o p t i o n s t o change −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− F l i g h t Mach number ( 0.32) [1] Flight altitude ( 1000 m) [2] Required S h a f t Power ( 975 kW) [3] Receiver altitude D i s t a n c e t o prop L a t e r a l d i s t a n c e t o prop Temperature change /ISA R e l a t i v e Humidity Execute

( 10 m) ( 300 m) ( 10 m)

[4] [5] [6]

( 0 K) ( 7 0 %)

[7] [8] [9]

E x i t / Quit [ any key ]

Figure 4.2 shows a graph of the predicted propeller performance for the F568 propeller model. The power coefficient CP is plotted against the advance ratio. Lines of constant propulsive efficiency are shown, along with the optimum efficiency envelope (dashed line).

Figure 4.2: Propeller F568, simulated flight performance. The propeller design data are given in a design file described in Listing 4.4.

4 Propeller Module

49 Listing 4.4: Propeller design data

”Unknown” ”1.1.0” ” clockwise ”

prop name prop version clock

! p r o p e l l e r name ! p r o p e l l e r model v e r s i o n ! s e n s e o f r o t a t i o n ( f r o n t view )

2 0.32 1.90 4 1.910

nsect rsect (1) rsect (2) nb design radius

! ! ! ! !

1100. 950. 900.

design rpm rpm climb rpm cruise

! d e s i g n rpm ( take−o f f ) ! rpm r a t i n g a t c l i m b c o n d i t i o n ! rpm r a t i n g a t c r u i s e c o n d i t i o n

[ no u n i t ] [ no u n i t ] [ no u n i t ]

5 d3 1 . 3 5 d2 1700 d3 0.30

design alt design TAS design power design cutoff

! ! ! !

[m] [m/ s ] [W] [m]

” chord ” 0.15 0.40 0.50 0.60 0.70 0.80 0.90 1.00

8 0.31 0.31 0.32 0.32 0.32 0.32 0.28 0.26

number radial radial number design

of reference sections position of inner section position of outer section of blades radius

design f l i g h t altitude design true a i r speed d e s i g n s h a f t power hub c u t o f f

[m] [m] [ no u n i t ] [m]

s t r i n g , n s i n p u t ! number o f r a d i a l p o s i t i o n s y/R, y/R, y/R, y/R, y/R, y/R, y/R, y/R,

chord chord chord chord chord chord chord chord

! ! ! ! ! ! ! !

spanwise spanwise spanwise spanwise spanwise spanwise spanwise spanwise

position position position position position position position position

& & & & & & & &

chord chord chord chord chord chord chord chord

[m] [m] [m] [m] [m] [m] [m] [m]

170.

prop mass

! p r o p e l l e r mass

0 . 2 5 d0

eps xx prop

! a n g l e between prop a x i s & a i r p l a n e a x i s

‘ ‘ sc1095 . polar ’ ’ sfilename (1) ‘ ‘ sc1094r8 . polar ’ ’ sfilename (2)

! polar f i l e , inner section ! polar f i l e , outer section

‘ ‘ s c 1 0 9 5 . dat ’ ’ ‘ ‘ s c 1 0 9 4 r 8 . dat ’ ’

! a i r f o i l s e c t i o n , hub ! a i r f o u l section , tip

foilname (1) foilname (2)

[ kg ] ‘ ‘x ’ ’

Chapter 5

Case Studies A limited number of results are shown to both demonstrate the capabilities of the program and its comparisons with reference data wind tunnel tests, flight recorder data, operating flight manual, etc.). We give an example (or more) in each of the main categories, except the geometric configuration, which is best explained by discussing the geometry report files.

5.1

Aerodynamics

Figure 5.1 shows the result of a blind test aimed at predicting the aerodynamic coefficients of the ATR72-500. The reference (experimental) data have been inferred from a technical report describing a fatal icing accident; further details are available in Ref. 1 . The lift is very well matched; the drag is slightly under-predicted. Note that the “reference” data have been estimated, therefore no attempt was made to narrow the gap with data which are not properly assessed.

2

0.5 Calculated CL (right scale) Calculated CD (left scale)

0.4

CL

0.3 1 0.2

CD x 10

1.5

0.5 0.1

0 -5

0

5

10

15

0 20

True angle of attack, degs

Figure 5.1: Predicted aerodynamic polars of the ATR72-500.

50

5 Case Studies

5.2

51

Airframe-Engine Integration: SAR Charts

Figure 5.2 shows an analysis of then specific air range performance of the Gulfstream G550, powered by the Rolls-Royce BR710A-10 turbofan engine. The case refers to standard day, no wind, flight level FL-370 (37,000 feet). The weights range from 60,000 to 80,000 pounds. A comparison with charts extracted from the flight manual is shown. The agreement is quite good, except at very high Mach numbers, when the transonic drag rise of the airplane seems to be extreme in comparison with the computed data. Additional discussion is available in Ref. 1 .

SAR, n-mile/lb

0.18

50 klb

0.4

0.36

0.16 60 0.32

0.14

70

SAR, n-mile/kg

Calculated Flight Manual

80 0.28

0.12

0.4

0.5

0.6

0.7

0.8

0.9

True Mach number

Figure 5.2: Selected SAR charts of the Gulfstream G550 and comparison with data in the flight manual.

5.3

Thermo-physics: Simulation of Fuel Tank Temperature

Thermo-physics problems include wing icing, tyre heating during ground roll and fuel temperature in flight. Here, we provide an example of the latter. Figure 5.3, adapted from Ref. 4 shows the simulated fuel tank temperature of the Boeing B777-200 that suffered at crash at London Heathrow in January 20081 . The fuel temperature model is fully synchronised with the flight mechanics. Details of the theoretical model are available in Refs. 4;1 . This case demonstrates that FLIGHT is capable of predicting the evolution of the fuel temperature in flight with reasonable agreement with the FDR data. 1

AAIB. Accident to Boeing B-777-236ER, G-YMMM at London Heathrow Airport on 17 January 2008, Interim Report EW/C2008/01/01, UK Dept. for Transport.

5 Case Studies

52

LIQ fuel Temp (ca VAP fuel Temp (ca * SAT Tank fuel volume* * Fuel Temperature

Temperature, K

260

240 Jet A1 freezing

220

200

0

180

360

540

Flight time, min

Figure 5.3: Fuel tank temperature of the Boeing B777-300, compared with data from the AAIB.

5.4

Aircraft Noise

This section shows an example of validation of the co-axial jet noise model. This case refers to a core flow having a temperature of 800 K, with the receiver at polar angle of 40 and 90 degrees, measured from the axis of the jet. Further details are available in Ref. 4 . All the noise components in FLIGHT are validated in isolation, then integrated and finally validated against real flight trajectories. Figure 5.5 shows the predicted noise footprint for an arrival trajectory of the Boeing B737-800. In this test case, there is an 8 kt sideways gust (90 degrees with respect to the ground track). Figure 5.6 shows a time frame of multiple operations from/to an airfield. In this specific case we have Boeing B737-800 on approach while another B737-800 is departing from the same runway, and a third airplane has already departed. The separation between these two flights is 90 seconds. The isolevels are OASPL[dB]. FLIGHT has the capability of modelling several aircraft movements at the same time, although computations become quite demanding.

5.5

Operational Performance: Payload-Range

There various types of calculations that can be carried out. The payload-range chart is certainly one of the most important. Figure 5.7 shows an example of fuel derivative calculation at constant BRGW for the Boeing B777-300 with GE-92 turbofan engines. Differences in the the derivative (dX/dm)BRGW are reflected in the slope of the of the OEW + payload weight versus aircraft range. This sensitivity parameter is discussed in Ref. 3 . Figure 5.8 shows the payload-range chart calculated for the Airbus A380-861 with GP7200 turbofan engines, and the comparison with the performance claimed by the manufacturer. Although the ferry-range is well within the tolerance of the manufacturer’s data, there are differences in the

5 Case Studies

53

90

SPL, dB

80

70

60

Calculated, θ = 40 deg Exp. data, θ = 40 deg Calculated, θ = 90 deg Exp. data, θ = 90 deg

50

40

2

3

4

log10 f

Figure 5.4: Validation of coaxial jet noise. maximum-fuel range, due to some discrepancies in the fuel derivative illustrated in the previous case (Figure 5.7). This is a problem that occurs often, but generally it is not wise to attempt to narrow this difference unless more information is provided on how the “reference” charts have been derived, and the actual conditions on the engines.

5.6

Longitudinal Dynamics

The next example refers to the longitudinal dynamics of the Airbus A320-211. The complete airplane was modelled, including the calculation of the aerodynamic derivatives. A solution for the short-period of motion at W = 58,800 [kg], altitude 2,000 [m], standard day, M = 0.300; KTAS = 193, KCAS = 176, CG position at 25% MAC. The response resulting from a step elevator input of 2 degrees is shown in Figure 5.9. This calculation is carried out from the “Performance Charts” menu, after selecting option [21] (Longitudinal Dynamics).

5.7

Propeller Performance

The analysis carried out with the propeller model on a F568 propeller in oblique flight, with a pitch angle of 5 degrees, and specified power is shown in Figure 5.10. This is a standard output for the propeller code.

5 Case Studies

54

(a) EPNL

2000

[m]

SEL[dB] 95 90 85 80 75 70 65

wind

1000 0

(b) SEL

-1000 -2000 -12000

-8000

-4000

[m]

0

4000

SEL[dB] 95 90 85 80 75 70 65

2000

wind

[m]

1000 0

(c) LAmax

-1000 -2000 -12000

-8000

-4000[m]

0

4000

2000

wind

[m]

1000 0

(d) PNLTM

-1000 -2000 -12000

-8000

-4000

[m]

0

4000

2000

wind

[m]

1000 0

LAmax[dBA] 100 95 90 85 80 75 70 65 60

(e) LAEQ

-1000

PNLTM[dBA] 105 100 95 90 85 80 75 70 65

Figure 5.5: Noise footprint at landing for a Boeing B737-800 with CFM56 engines. Travel is from -2000 -12000 -8000 -4000 0 4000 left to right. [m]

2000

[m]

1000 0

-1000 -2000

wind

LAeqT[dB] 75 70 65 60 55 50 45

5 Case Studies

55

arriving departing

0

[k m

5

]

Flight V. 6.2.6

10

-2

[k m 0 ]

2 15

Figure 5.6: Noise footprint from multiple movements of a Boeing B737-800 with CFM engines at take-off/departure. Levels shown are OASPL[dB].

OEW + Payload, tons

225

Boeing’s d Calculated

MZFW = 224.540 tons

200

175

BRGW = 235.8 tons

150

1

2

3

4

3

Range, 10 n-miles

Figure 5.7: Fuel-payload sensitivity for the Boeing B777-300 at constant BRGW; comparison with Boeing’s data, from Ref. 3 .

5 Case Studies

56

100 MSP = 90,718 kg

Calculated

MSP = 83,700 kg

Payload, tons

80

60

AIRBUS Data Max Pax Load

40

20

0 2000

4000

6000

8000

10000

Range, n-miles

Figure 5.8: Payload-range chart of the Gulfstream G550, standard day, no wind.

1 attitude pitch rate

α [deg], q [deg/s]

0.5

0

-0.5

-1

-1.5

2

4

6

8

10

12

Time, s

Figure 5.9: Short period of motion of the Airbus A320-211 airplane model.

5 Case Studies

57

dCP 1.10E-03 9.00E-04 7.00E-04 5.00E-04 3.00E-04

Ψ=0

Figure 5.10: Distribution of power coefficient on the F568 propeller model in a 5-degree pitch flight.

Chapter 6

Selected Output Files & Data The program FLIGHT can provide in excess of 100 output files; to the novice, it can be a daunting task to muddle through all this amount of data. Each operation invoked will provide at least one output file, and in some cases several files. Case studies are issued separately.

6.1

AEO Take-off of an A320 Model

The print-out below shows a summary of performance data for a normal take-off of an Airbus A320211 powered by CFM56 turbofan engines. Most of the parameters should be self-explanatory. Note that the header contains information about the version of the softare, the database, the propeller version, the software build level, the airplane model, the engine model, etc. The report ends with a tag with a run number which is unique. -------------------------------------------------------FLIGHT Version : 6.0.3 Revision : b Database : 17.0.1 Prop_Noise : 3.8.3 Level : 1750/21.6% Licensed to : Owner Copyright (C) A. Filippone (2013) All rights reserved The University of Manchester Manchester, United Kingdom -------------------------------------------------------JOB IDENTITY -------------------------------------------------------Run Time: Thursday 25 April 2013 at 13:28 Computer platform is Windows Airplane/Engine/Data are CLASSIFIED Airplane = Airbus A320-200-CFM; Version 1.1.0 Engine = CFM56-5C4P ; Version 2.1.3 APU = 131-9 -------------------------------------------------------Gross take-off weight (W) = Airfield altitude (A) = Air temperature (T) = Wind speed = Runway state = Tyre-road slip ratio =

64.317 [ton] 50.00 [m] 0.00 +/- ISA -2.00 [m/s]; -3.9 [kt] dry 0.025

58

6 Output Data

59

Flap setting Max lift coefficient Stall speed

= = =

Roll friction coeff. Brake friction coeff.

= =

20.000 [deg] 2.421 51.93 [m/s];

100.95 [kt]

0.025 0.180

Thrust angle = 0.000 [degs] Stall margin = 1.150 CG position wrt nose = 16.400 [m] xCG = 30.00 [% MAC] Pitch moment of inertia = 3.86 [10^6 kgm2] -----------------------------------------------------------FLAP setting Rotation Velocity Rotation distance Rotation Time Lift-off Velocity

= (VR) = (XR) = (TR) =

20 79.42 886.38 25.55

[deg] [m/s]; [m] [s] [m/s]; [kt] [m] [s] [m/s];

(VLO) (CAS) (XLO) (TLO) (VTO)

= = = = = = =

87.32 178.33 1105.34 28.70 92.05 16.343 1.425

Mach no. over screen Distance to screen (XTO) Time over screen (TTO) Climb angle over screen

= = = =

0.271 1319.32 [m] 31.50 [s] 6.51 [deg]

Total take-off distance Total take-off time Fuel burn Minimum control speed, VMCG Stall speed , VS Max (main) tyre temperature Max (nose) tyre temperature Main tyre temp. over screen Nose tyre temp. over screen

= = = = = = = = =

1319.32 31.50 178.02 61.91 51.93 292.1 399.6 291.0 300.0

Lift-off distance Lift-off Time Velocity over screen Lift/Drag over screen Lift-off CL

154.39 [kt]

169.74 [kt]

178.94 [kt]

[m] [s] [kg] [m/s] 120.34 [kt] [m/s] 100.95 [kt] [K] rise = 1.2 [K] [K] rise = 99.6 [K] [K] [K]

Brake-release net thrust = 84.820 [kN] Brake-release f-flow = 2.813 [kg/s] -----------------------------------------------------------Vortex Wake Characteristics at take-off -----------------------------------------Average downwash = 0.0359 [m/s] Downwash mass flow = 137.32 [kg/s] Reference wake time = 14.72 [s] Reference wake length = 14.72 [m] Reference wake speed = 1.82 [m/s] ** End Report 603b701, Run 360

6 Output Data

6.1.1

60

AEO Climb of an Airbus-A320 Airplane Model

The following block shows a report for the climb to an initial cruise altitude. The terminal point of the climb (M, z) is determined by local optimisation. This optimisation leads to the best flight level and the best Mach number, which is then used as a target for the climb shown below. -------------------------------------------------------FLIGHT Version : 7.1.7 Revision : b Database : 20.2.0 Prop_Noise : 3.8.1 Build : 4846/50.7% Licensed to : Owner -------------------------------------------------------JOB IDENTITY -------------------------------------------------------Run Time: Monday 24 November 2014 at 16:53 Computer platform is Windows Airplane/Engine/Data are CLASSIFIED Airplane = Airbus A320-200-CFM; Version 1.3.0 Engine = CFM56-5C4P ; Version 3.1.1 APU = 131-9 -------------------------------------------------------KCAS

KTAS

Mach

z time vc vc mf fflow [m] [min] [m/s] [f/min] [kg] [kg/s] ----------------------------------------------------------------------------------155.85 156.43 0.237 80.7 0 0.401 988.2 3.64 4.20 828. 121.5 0.557 1 250.00 289.21 0.451 3118.0 3.18 15.97 3143. 141.8 0.743 2 250.00 289.21 0.451 3118.0 0.00 0.00 0. 0.0 0.347 3 248.57 429.91 0.748 11012.3 19.92 6.60 1300. 479.8 0.401 4 237.79 429.52 0.748 11582.4 2.00 4.83 950. 44.6 0.371 -----------------------------------------------------------------------------------

[over screen] [800-ft target] [const CAS] [accelerate] [const CAS] [const Mach]

Time to ICA = 28.7 [min] Fuel to ICA = 787.8 [kg] Dist to ICA = 157.6 [n-miles] Avg fuel flow = 1644.2 [kg/hr] L-Gear retraction 6 [m] / 19 [ft] above airfield Flaps retraction 80 [m] / 262 [ft] above airfield Transition altitude 2959 [m] / L-Gear retraction time = 6.3 [s] after take-off ** End Report 603b701, Run 360

Selected points in the climb are shown in the report above. For each flight segment, the report shows the distance flown, the flight time, the average climb rate (vc), the fuel burn (mf), the average fuel flow (fflow). At the bottom of the report there is a summary of the climb performance, with data such as landing gear retraction, full flaps retraction, etc. The most important data from the mission planning point of view are the time, fuel and distance to initial cruise altitude (ICA).

6 Output Data

6.1.2

61

Cruise Performance of an Airbus A320 Airplane Model

The following output shows an example of cruise report. In this specific case, the aircraft flies at a constant flight level for the entire duration of the cruise (about 560 n-miles). Both Initial Cruise Weight (ICW), Initial Cruise Altitude (ICA) and cruise Mach numbers are optimised; FLIGHT returns an economical Mach number Meco = 0.748. Note that the flight level is often adjusted down, since the optimal level is unrealistic (for example, FL-380). Note that in this case there is no step climb. -------------------------------------------------------FLIGHT Version : 7.1.7 Revision : b Database : 20.2.0 Prop_Noise : 3.8.1 Build : 4846/50.7% Licensed to : Owner -------------------------------------------------------JOB IDENTITY -------------------------------------------------------Run Time: Monday 24 November 2014 at 16:53 Computer platform is Windows Airplane/Engine/Data are CLASSIFIED Airplane = Airbus A320-200-CFM; Version 1.3.0 Engine = CFM56-5C4P ; Version 3.1.1 APU = 131-9 -------------------------------------------------------[Segment]: Cruise: X =

557.8 [nm]; FL-380; ICW =

61.746 [ton]; M = 0.748

h FL X time fuel fflow vc vc [m] [n-m] [min] [kg] [kg/s] [m/s] [f/min] ----------------------------------------------------------------------------11582 380 557.8 77.23 2460.7 0.531 ----------------------------------------------------------------------------Summary: 557.8 77.23 2460.7 0.531

6 Output Data

6.1.3

62

En-Route Descent of an Airbus A320 Airplane Model

For the same example as shown before, we present the en-route descent of the Airbus A320 from the end of the cruise down to 1,500 feet above airfield elevation. The critical segments are indicated line by line. -------------------------------------------------------FLIGHT Version : 7.1.7 Revision : b Database : 20.2.0 Prop_Noise : 3.8.1 Build : 4846/50.7% Licensed to : Owner -------------------------------------------------------JOB IDENTITY -------------------------------------------------------Run Time: Monday 24 November 2014 at 16:53 Computer platform is Windows Airplane/Engine/Data are CLASSIFIED Airplane = Airbus A320-200-CFM; Version 1.3.0 Engine = CFM56-5C4P ; Version 3.1.1 APU = 131-9 -------------------------------------------------------EN-ROUTE DESCENT REPORT --------------------------------------------Initial mass = 59.14 [ton] Initial Altitude = 11582 [m]; 38000 [feet] Final Altitude = 523 [m]; 1717 [feet] Initial KTAS = 429.52 KCAS = 237.97 Final KTAS = 202.39 KCAS = 197.52 Final Mach = 0.308 Final Vs = 5.31 [m/s] Descent distance = 116.05 [nm] Descent time = 22.52 [min] Descent fuel = 273.01 [kg] Continuous Descent = NO --------------------------------------------KCAS

KTAS

Mach

Z time X vc vc mf fflow [m] [min] [n-m] [m/s] [f/min] [kg] [kg/s] ----------------------------------------------------------------------------------------------0 237.97 429.52 0.748 11582 [Top of Descent] ---------------------------------------1 237.97 202.39 0.748 11582 0.82 5.88 12.03 2368 9.2 0.000 [Segment 1] 2 237.97 287.65 0.451 3110 12.92 75.44 10.17 2002 155.8 0.201 [Segment 2] 3 217.97 253.58 0.395 3110 1.98 11.15 0.00 0 24.1 0.344 [Segment 3] 4 217.97 227.76 0.348 979 18.38 97.38 1.93 380 223.4 0.681 [Segment 4] 5 217.97 207.95 0.316 979 2.72 13.82 0.00 0 33.0 0.751 [Segment 5] 6 217.97 202.39 0.308 523 19.80 102.23 0.38 75 240.0 2.823 [Segment 6] ----------------------------------------------------------------------------------------------TOTALS 22.52 116.05 273.0 ** End Report 717b2020

, Run 353

6 Output Data

6.1.4

63

Mission Report of an A320 Model

The case below is a summary of mission calculations (Option 1 in Listing 3.4). There are various sub-headings: a.) Aircraft state; b.) Summary of Mission Specifications; c.) Fuel Use Report; d.) Estimated Trip Time; e.) Fuel Breakdown Report; f.) Aircraft Mass/Weight Report; g.) Final Mass/Weight Report; h.) Summary of Flight Conditions; i.) LTO Report. a.) Airplane State: ------------------Airframe = new Engines = new b.) Summary of Mission Specifications: --------------------------------------------Required range = 809.9 [n-miles] Required bulk payload = 0.0 [ton] Required pax = 100.0 [% of full capacity] c.) Fuel Use Report -------------------------------------------------------------------------------USED fuel = 5132.1 [kg] Climb fuel = 822.2 [kg], 16.02% , dist = 127.13 [nm], time = 22.0 [min] Cruise fuel = 3003.1 [kg], 58.52% , dist = 580.62 [nm], time = 79.6 [min] Descent fuel = 634.9 [kg], 12.37% , dist = 123.78 [nm], time = 25.1 [min] Takeoff fuel = 178.0 [kg], 3.47% Taxiout fuel = 120.7 [kg], 2.35% , dist = 1.62 [nm], time = 10.0 [min] APU/ECS fuel = 275.2 [kg], 5.36% Taxi-in fuel = 77.8 [kg], 1.52%, from reserve -------------------------------------------------------------------------------d.) Estimated trip time: -------------------------------------------------Takeoff-Climb-Cruise-Descent = 129.4 [min] Block time, incl. taxi/roll = 147.4 [min] Payload Fuel Efficiency Theoretical range Effective range Equivalent all-out range

= = = =

5401.64 809.94 1060.85 1106.60

[ton*nm/hr] [nm] [nm] [nm]

e.) Fuel Breakdown Report -------------------------------------------------Taxiout fuel = 120.7 [kg] Takeoff fuel = 178.0 [kg] Climb fuel = 822.2 [kg] Cruise fuel = 3003.1 [kg] Descent fuel = 634.9 [kg] Approach fuel = 20.3 [kg] APU/ECS fuel = 275.2 [kg] Div./Hold fuel = 764.7 [kg] Reserve fuel = 294.8 [kg] -------------------------------------------------Total = 6191.7 [kg] 33.1% of full tanks 33.3% of usable fuel f.) Aircraft Mass/weight Report -------------------------------------------------Ramp weight = 64456.9 [kg] Brake release = 64317.0 [kg] Takeoff = 64137.9 [kg] Climb = 63273.4 [kg] Cruise = 60117.1 [kg] Descent = 59433.8 [kg] Approach = 59410.2 [kg]

6 Output Data

64

g.) Final Mass/Weight Report -------------------------------------------------OEW = 42.256 [ton] Bulk payload = 0.000 [ton] Passengers = 12.000 [ton] baggage = 2.400 [ton] Flight crew = 0.570 [ton] pilots = 2; flight attendants = 4 Useful payload = 14.380 [ton] Service items = 1.060 [ton] Fuel = 6.192 [ton] non usable = 112 [kg] (estimated) Ramp Weight = 64.159 [ton] Brake Release G.W. = 64.337 [ton] Zero-fuel Weight = 58.266 [ton] Take-off Weight = 56.239 [ton] Final Cruise Weight = 63.273 [ton] Landing Weight = 59.325 [ton] -------------------------------------------------h.) Summary of Flight Conditions & Assumptions -------------------------------------------------Outbound taxi time [min] = 10 Inbound taxi time [min] = 8 Climb schedule KCAS [kt] = 250.0; 265.6 Cruise Mach = 0.751 Wind speed at cruise [m/s] = 0.0 Change in temperature [K] = 0.0 Takeoff airfield alt [m] = 50.0 Landing airfield alt [m] = 50.0 -------------------------------------------------Hold altitude [m] = 507 , 1664 [ft] Hold time [min] = 30.0 Hold Mach number = 0.350 Green-Dot speed [kt] = 197.30 Hold fuel flow [kg/s] = 0.519 Diversion distance [n-m] = 200.0 Initial Cruise Alt. [m] = 12077 , 39753 [ft] Final Cruise Alt. [m] = 10058 , 33000 [ft] Baggage allowance/pax Average pax weight

= =

15 [kg] 75 [kg]

i.) LTO Split, by integration [kg] CO NOx HC t[min] ------------------------------------------------------------------1. Taxiout, roll 1.065 0.193 0.077 6.7 2. Taxiout, idle 2.131 0.385 0.154 3.3 3. Takeoff 4.621 1.613 0.209 0.5 4. Climbout 1.181 0.710 0.014 1.2 5. Approach 1.331 2.365 0.026 3.0 6. Landing 0.168 0.161 0.010 0.9 7. Taxi-in, roll 0.423 0.064 0.031 6.7 8. Taxi-in, idle 2.117 0.320 0.154 1.3 9. APU (total) 0.018 0.025 0.001 23.6 ------------------------------------------------------------------Total LTO 13.037 5.810 0.674 23.6 ** End Report 603b701, Run 360

Nomenclature

6.2

65

Nomenclature & Conventions

Flight Mechanics AEO AGL AUW APU BRGW CAS CG EGT FAR FCW FDR FL FLS GLW GRW GTOW HPC HPT ICA ICW ISA IFLAP ISLAT LPC LPT LTO OAT OEI OFLAP OSLAT MLR MMR MMO MSP MZFW SAR SAT TAS TAT TOW TSFC VMCG ZFW

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

All Engines Operating Above Ground Level All-up weight Auxiliary Power System Brake-release Gross Weight Calibrated Air Speed Center of Gravity Exhaust Gas Temperature Federal Aviation Regulations Final Cruise Weight Flight Data Recorder Flight Level Flight Level Separation Gross Landing Weight Gross Ramp Weight Gross Take-Off Weight High Pressure Compressor High Pressure Turbine Initial Cruise Altitude Initial Cruise Weight International Standard Atmosphere Inboard Flap Inboard Slat Low Pressure Compressor Low Pressure Turbine Landing and Take-off Outside Air Temperature One Engine Inoperative Outboard Flap Outboard Slat Long-Range Mach Number Maximum-Range Mach Number Maximum Operating Mach Number Maximum Structural Payload Maximum (design) Zero-Fuel Weight Specific Air Range Static Air Temperature True Air Speed Total Air Temperature Take-off Weight Thrust-Specific Fuel Consumption Minimum Control Speed on the Ground Zero-fuel weight

Nomenclature

66

Noise Metrics EPN LAmax LAEQ PNL PNLTM SEL SPL TAUD

= = = = = = = =

Effective Perceived Noise Level (also EPNL) A-weighted Maximum Sound Pressure Level Equivalent Sound Level (also LAeqT) Perceived Noise Level Perceived Noise Level, Maximum Value Sound Exposure Level Sound Pressure Level Time-Audible

Noise Breakdown SRCt[s] RECt[s] x[km] y[km] s[km] h[km] h[kft] r[km] theta KTAS LGear Flap Wing HSTAB VSTAB SLAT FLAP NLG MLG FAN LPC HPC COMB HPT LPT JET Prop APUC APUJ OASPLa OASPLe OASPL PNL Loud

= = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =

source (flight) time, s receiver (flight) time, s flight distance, x-direction, km flight distance, yx-direction, km ground track, km geometrical altitude of the airplane, km geometrical altitude of the airplane, 1,000 feet distance CG to receiver on the ground, km polar emission angle, degs true air speed, kt flag to denote landing gear deployed (1) or retracted (0) high-lift position: 1, 2, · · · wing noise horizontal stabiliser noise vertical stabiliser noise slat noise flap noise nose landing gear noise main landing gear noise fan noise (corrected for duct absorption & duct acoustics)x low-pressure compressor noise high-pressure compressor noise combustor SPL high-pressure turbine noise low-pressure turbine noise coaxial jet SPL propeller noise APU compressor noise APU jet noise overall sound pressure level, airframe overall sound pressure level, engine overall sound pressure level perceived noise level, dBA loudness, dBA

Nomenclature

67

Noise Trajectories WC[kg/s] W1[kg/s] FN[kN] N1% TT4[K] TT5[K] EGT[K]

= = = = = = =

core mass flow rate, kg/s mass flow rate, kg/s net thrust, kN gas generator turbine speed, in percent combustor entrance temperature, K high-pressure turbine temperature, K exhaust gas temperature, K

Payload-Range Charts X[nm] Xc[nm] GRW BRGW GTOW FCW GLW WPay Wfuel Wfclimb Wfcruise Wfdes Wfburn SAR[nm/kg] CO2 ICA FCA MLR t[min] block[min] Mobs Gobs Tobs

= = = = = = = = = = = = = = = = = = = = = = =

range, n-miles en-route climb distance, n-miles gross ramp weight, ton brake-release gross weight, ton gross take-off weight, ton final cruise weight, ton gross landing weight, ton payload weight, ton fuel weight, ton climb fuel, ton cruise fuel, ton descent fuel, ton fuel burned, ton average specific air range, n-miles/kg CO2 emissions, ton initial cruise altitude (flight level) final cruise altitude (flight level) long-range Mach number flight time, minutes block time, minutes Mach number over screen (takeoff) Initial climb gradient (takeoff) Time over screen (take-off)

Nomenclature

68

Gas Turbine Engine Symbols FN Mach9 N%1 N%2 PS9 PT3 PT14 PT2.5 TSFC TS9 TT2.1 TT2.2 TT2.5 TT3 TT4 TT5 TT14 W1 WC2.5 Wf 6 W14

= = = = = = = = = = = = = = = = = = = = =

Net thrust Nozzle Mach number (core side) Low pressure rotor rpm, % High pressure rotor rpm, % Total static nozzle pressure HP Compressor pressure, exit Bypass flow total pressure, exit LP compressor exit pressure Specific fuel consumption Total static nozzle temperature Exit fan temperature (core side) Exit fan temperature (bypass side) LP compressor exit temperature Combustor inlet temperature Exit combustor temperature Power turbine temperature Bypass flow temperature, exit Mass flow rate Core mass flow rate Fuel flow rate By-pass mass flow rate

Bibliography [1] Filippone A. Advanced Aircraft Flight Performance. Cambridge University Press, 2012. [2] Filippone A. Flight Performance of Fixed and Rotary Wing Aircraft. Elsevier, 2006. [3] Filippone A. Comprehensive analysis of transport aircraft flight performance. Prog. Aerospace Sciences, 43(3), April 2007. [4] Filippone A. Theoretical framework for the simulation of transport aircraft flight. J. Aircraft, 47(5):1679–1696, 2010. [5] Filippone A. On the benefits of lower Mach number aircraft cruise. 111(1122):531–542, Aug. 2007.

Aeronautical J.,

[6] Filippone A. Steep-descent manoeuvre of transport aircraft. J. Aircraft, 44(5):1727–1739, Sept. 2007. [7] Filippone A. Cruise altitude flexibility of jet transport aircraft. Aero. Science & Technology, 14:283–294, 2010. [8] Filippone A. Encyclopaedia of Aerospace Engineering, volume 5, chapter Longitudinal Static Stability, 252, pages 2651–2660. John Wiley & Sons Ltd, 2010. [9] Filippone A. Encyclopaedia of Aerospace Engineering, volume 5, chapter Lateral Static Stability, 253, pages 2661–2668. John Wiley & Sons Ltd, 2010. [10] Filippone A, Bertsch L, and Pott-Pollenske M. Validation strategies for comprehensive aircraft noise prediction methods. In 12th AIAA/ATIO Conference, Indianapolis, IN, Sept. 2012. [11] Filippone A. Recent progress in comprehensive models for aircraft flight. In CEAS Conference, Manchester, UK, Oct. 2009. [12] Filippone A. Challenges in aircraft noise prediction. In Green Aviation Conference, number Paper 2968130, Brussels, BE, March 2014. [13] Filippone A and Bertsch L. Comparison of aircraft noise models with flyover data. J. Aircraft, 51(3), 2014. DOI: 2514/1.C032368. [14] Filippone A. Aircraft noise prediction. Progress in Aerospace Sciences, 68:27–63, July 2014. doi: 10.1016/j.paerosci.2014.02.001. [15] Hughes R & Filippone A. Flyover noise measurements and simulation for a turboprop aircraft. In Internoise, Innsbruck, Austria, Sept. 2013.

69

Nomenclature

70

[16] Filippone A and Mohammed-Kassim Z. Multi-disciplinary simulation of propeller-turboprop aircraft flight. Aeronautical Journal, 116(1184):985–1014, Oct. 2012. [17] Filippone A. Validation strategies of aircraft noise with measured data. Aeronautical J., 119:595–619, May 2015. [18] Filippone A. Analysis of carbon-dioxide emissions from transport aircraft. 45(1):183–195, Jan. 2008.

J. Aircraft,

[19] Filippone A. Assessment of aircraft contrail avoidance strategies. J. Aircraft, 52(3):872–878, May 2015. DOI:10.2514/C033176. [20] Filippone A. Range performance improvement with morphing wing configurations. In Royal Aero Soc. Structural Design Conference, Oct. 2014. doi:10.13140/2.1.3430.7848. [21] Filippone A. Rapid estimation of airfoil aerodynamics for helicopter rotor calculations. J. Aircraft, 45(4):1468–1472, Jul. 2008. doi:10.2514/1.35560.

Appendix A

List of User-Defined Parameters Listing A.1: User-Defined Parameters, Part 1 Name Value Description −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− !− User−Parameters : ENGINES −−−−−−−−−−−−−−−−−−− user RSS comp = 50 d0 ! r e l a t i v e r o t o r −s t a t o r d i s t a n c e , any CPR s t a g e user RSS fan = 250 d0 ! r e l a t i v e fan−vanes d i s t a n c e user liner thick = 0 . 0 6 6 7 ! a c o u s t i c l i n e r depth , f r a c t i o n , f a n d i a m e t e r user Mtipd CPR = 1 . 1 0 d0 ! max CPR r o t a t i n g t i p Mach number u s e r c o r e f a n d i a m r a t i o = 0 . 4 7 5 ! v a l i d with a p p r o x i m a t i o n f o r with BPR = 5 t o 8 user PRduct = 0 . 0 2 9 0 ! l o s s i n p r e s s u r e i n bypass duct user SR CPR blade = 10 ! n b l a d e s s t a t o r − n b l a d e s r o t o r , any CPR s t a g e user blade row SR = 3 ! d i f f e r e n c e [ s t a t o r − r o t o r ] b l a d e s , s i n g l e row user TRB blades 1HP = 85 ! number o f b l a d e s , 1 s t s t a g e HPT user etacpr = 0 . 9 8 d0 ! s i n g l e −s t a g e c o m p r e s s o r e f f i c i e n c y user cycle wash = 1000 ! number o f e n g i n e c y c l e s b e f o r e washing user kinl = 0 . 2 5 d0 ! e s t i m a t i o n o f e n g i n e i n s t a l l a t i o n l o s s e s , % user tsfc ploss = 0 . 1 d0 ! permanent e f f i c i e n c y l o s s a f t e r e n g i n e wash , % user ploss = 2 . 5 5 d−2! permanent e f f i c i e n c y l o s s a f t e r wash user TRB heat flow = 4d−2 ! h e a t f l o w r a t e out o f c o r e f l o w ( f r a c t i o n ) user power ratio = 2 . 5 d0 ! maximum ge arbo x power l o s s , % max power user engine ttime = 3 d0 ! r e l a x a t i o n time f o r t r a n s i e n t e f f e c t s [ s ] !− User−Parameters : WING & user outer thickness user inner thickness user kflap user kslat user slat perim user max rudder deflect user max aileron deflect user max spoiler deflect user max elevator deflect user max HT deflect plus user max HT deflect min user max roll rate user theta rudder user delta aileron user delta spoil user varphi deg

CONTROL SURFACES −−− = 0 . 9 0 ! wing t h i c k n e s s a t t i p , r e f e r e n c e = 1 . 1 4 ! wing t h i c k n e s s a t r o o t , r e f e r e n c e = 1 . 7 0 ! i n c r e m e n t a l c o e f f i c i e n t , f l a p area , i f unknown = 0 . 9 0 ! i n c r e m e n t a l c o e f f i c i e n t , s l a t area , i f unknown = 2 . 5 0 ! r a t i o p e r i m e t e r / chord = 25 d0 ! max . r u d d e r d e f l e c t i o n , d e g r e e s = 25 d0 ! max . a i l e r o n d e f l e c t i o n , d e g r e e s = 60 d0 ! max . s p o i l e r d e f l e c t i o n , d e g r e e s = 20 d0 ! max . e l e v a t o r d e f l e c t i o n , d e g r e e s = 1 3 . 5 ! max . h− t a i l d e f l e c t i o n , d e g r e e s = −4d0 ! min . h− t a i l d e f l e c t i o n d e g r e e s = 15 d0 ! max . r o l l r a t e , d e g r e e s / s = 15 d0 ! max . r u d d e r d e f l e c t i o n , d e g r e e s = 20 d0 ! max . a i l e r o n d e f l e c t i o n , d e g r e e s = 70 d0 ! max . s p o i l e r d e f l e c t i o n , d e g r e e s = 5 d0 ! l i m i t bank a n g l e f o r VMCA, d e g r e e s

71

User-Defined Parameters

72 Listing A.2: User-Defined Parameters, Part 2

Name Value Description −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− !− User−Parameters : AERODYNAMICS −−−−−−−−−−−−−− user kkorn = 0 . 1 3 9 5 ! Korn f a c t o r t o e s t i m a t e t r a n s o n i c drag r i s e user tlag flap = 2 d0 ! time d e l a y between f l a p d e f l e c t & a e r o l o a d s [ s ] !− User−Parameters : WING user tank thickness user xle wing tank user xte wing tank user span wing tank

TANKS −−−−−−−−−−−−−−−− = 0 . 3 5 d−2! a v e r a g e thank s h e l l t h i c k n e s s [m] = 0 . 1 5 d0 ! f o r w a r d p o s i t i o n o f wing tank (LE) = 0 . 3 2 d0 ! a f t p o s i t i o n o f wing tank (TE) = 0 . 7 1 d0 ! wing tank span , f r a c t i o n o f wing semi−span [m]

!− User−Parameters : TYRE QUANTITIES −−−−−−−−−−− user tyre gas = ” a i r ” ! tyre i n f l a t i o n gas user max tyre deflect = 32 d0 ! max . t y r e d e f l e c t i o n , % user hysteresis = 0.120 ! thermal h y s t e r e s i s o f tyres , f r a c t i o n !− User−Parameters : OTHER GEOMETRY −−−−−−−−−−− user shell thick = 0 . 0 8 0 ! f u s e l a g e s h e l l t h i c k n e s s [m] , a v e r a g e user pitch down = −1d0 ! nose−down a t t i t u d e on t h e ground , d e g s user xCGMAC min = 18 d0 ! maximum f o r w a r d p o s i t i o n o f CG wrt t o MAC user xCGMAC max = 45 d0 ! maximum a f t p o s i t i o n o f CG wrt t o MAC !− User−Parameters : FLIGHT OPERATIONS −−−−−−−−− user turb = 0 . 2 d0 ! f r e e stream t u r b u l e n c e f o r f l i g h t a n a l y s i s , % user runway max length = 3 d3 ! maximum runway l e n g t h [m] user utaxi = 5 d0 ! a v e r a g e ground / t a x i speed , m/ s user xroll max = 2 . 0 d0 ! a v e r a g e r o l l / ground d i s t a n c e , km user timelag spoiler = 0 . 7 5 0 ! take−o f f / l a n d a b o r t : s p o i l e r r e s p o n s e time [ s ] user timelag brake = 0 . 5 d0 ! take−o f f a b o r t : b r a k e s r e s p o n s e time [ s ] user Vgstab = 12 d0 ! min . ground s p e e d f o r s p o i l e r s deployment user RevThrust frac = 0 . 1 5 d0 ! r e v e r s e t h r u s t o p t i o n s , f r a c t i o n user URevThrust = 100 d0 ! min s p e e d f o r r e v e r s e t h r u s t , [ km/h ] user lim rot time = 2 . 5 d0 ! max . r o t a t i o n time a t f l a r e / t a k e o f f [ s ] user vbrake = 15 d0 ! max . b r a k i n g s p e e d a t l a n d i n g , km/h user hLGDeploy = 450 d0 ! h e i g h t o f LG deployment , above a i r f i e l d [m] user hLGRetract = 76 d0 ! h e i g h t o f LG r e t r a c t i o n , above a i r f i e l d [m] u s e r t d e l a y L G r e t r a c t S L = 2 . 5 d0 ! time d e l a y between LG r e t r a c . & f l a p r e t r a c t . user tdelay F2 = 5 d0 ! time d e l a y between LG d e p l o y & FLAP2 s w i t c h [ s ] use r w b ag = 15 d0 ! baggage a l l o w a n c e [ kg ] user wpax = 75 d0 ! avg w e i g h t o f p a s s e n g e r [ kg ] user wcrew = 95 d0 ! avg w e i g h t o f crew + baggage [ kg ] user unusable fuel = 0.006 ! unusable fuel , f r a c t i o n user ncrew first class = 11 ! passengers per f l i g h t attendant , b u s i n e s s c l a s s user ncrew tourist = 31 ! p a s s e n g e r s p e r f l i g h t a t t e n d a n t , economy c l a s s user seat mass1 = 21 d0 ! s e a t mass , economy [ kg ] user seat mass2 = 42 d0 ! s e a t mass b u s i n e s s [ kg ] user seat other = 15 d0 ! s e a t −r e l a t e d mass [ kg ] user idle time = 1 5 6 0 . 0 ! i d l e time = 26 minutes (ICAO) , c o n v e r t e d t o [ s ] user kpaxo = 3 d0 ! min . w e i g h t o f s e r v i c e s / p a s s e n g e r [ kg / pax ] user kpax dx = 0 . 5 d0 ! r a t e o f i n c r e a s e o f s e r v i c e s / p a s s e n g e r [ kg / pax ] u s e r m i n t u r b o p r o p r a n g e = 150 d0 ! min . r a n g e o f t u r b o p r o p a i r p l a n e , [ km ] u s e r m i n t u r b o f a n r a n g e = 250 d0 ! min . r a n g e o f t u r b o f a n a i r p l a n e , [ km ] user Mach DIVE = 1 . 0 7 0 ! DIVE Mach number d e f i n e d a s : MMO* user Mach DIVE user NLF UTurn = 1 . 1 5 0 ! normal l o a d f a c t o r used f o r U−t u r n

User-Defined Parameters

73 Listing A.3: User-Defined Parameters, Part 3

Name Value Description −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− !− User−Parameters : FLIGHT MANOUVRES −−−−−−−−−− user hclimb turn = 4 0 0 . 0 ! a l t i t u d e a t which a i r c r a f t p e r f o r m s t u r n [m] user drift = 30 d0 ! max . a l l o w e d s i d e w a y s d r i f t , OEI take−o f f [ f t ] user tyre yaw = 5 d0 ! f i x e d t y r e yaw d u r i n g VMCG [ d e g s ] user dpshell = 5 9 . 3 d3 ! max . p r e s s u r e d i f f e r e n c e between c a b i n & e x t !−−−− user user user user user user user user user user user user

User−Parameters : NOISE −−−−−−−−−−−−−−−−−−−−− Lturbscale = 1 . 1 d1 ! t u r b . l e n g t h s c a l e , n o i s e p r o p a g a t i o n [m] floor dB = 1d−2 ! min . SPL [ dB ] ; a v o i d s o v e r f l o w , NaN, i n l o g ops rmax noise = 9 . 6 7 d3 ! max . d i s t a n c e t o c a l c u l a t e n o i s e [m] romax noise = 3 . 1 5 d3 ! max . d i s t a n c e on ground t o c a l c u l a t e n o i s e [m] max noise alt = 1 . 5 d3 ! max a l t i t u d e AGL f o r n o i s e c a l c u l a t i o n s [m] Vmin Anoise = 3 d0 ! min . a i r s p e e d f o r a i r f r a m e n o i s e [m/ s ] min sep time = 55 d0 ! min . f l i g h t s e p a r a t i o n time [ s ] max sep time = 180 d0 ! max . f l i g h t s e p a r a t i o n time [ s ] build height = 4 d0 ! a v e r a g e b a r r i e r h e i g h t o f b u i l d i n g s , [m] SPL shielding = 55 d0 ! min . SPL t o t r i g g e r wing / e n g i n e / prop s h i e l d i n g wind noise = 2.060 ! min . a i r f i e l d wind s p e e d i n n o i s e propag . [m/ s ] m a x p r o p d i s t a n c e = 1 . 5 d3 ! max d i s t a n c e prop−r e c e i v e r f o r p r o p e l l e r n o i s e

!− User−Parameters : OTHER STUFF −−−−−−−−−−−−−−− user pop density = 2300 ! a v e r a g e o f S t o c k p o r t / S a l f o r d [ p e o p l e /kmˆ 2 ]

Index AAIB, 52 Acoustic liners, 36 AGL, 39 Airbus A320-211, 22 Airbus A380, 44, 53 Aircraft design, 6 APU, 6, 11, 23 ASCII files, 14 Atmosphere, 8, 11, 20–22 Background noise, 36 Batch jobs, 42 Boeing B737, 53 Boeing B777, 52 Contrails, 5, 11, 22 Cost functions, 43 CPU, 34, 42

directivity, 35 maps, 44 Phogoid, 28 Propeller, 27, 42, 47 Hamilton F568, 54 Restart, 45 Short-period of motion, 28 Specific air range (SAR), 52 Specific excess power (SEP), 28 Thermo-physics, 52 Tools aerodynamics, 45 noise maps, 44 propulsion, 46 Type certificate, 6

Demo version, 13 Direct operating costs, 39–40 DLL, dynamic link library, 6

VMCA, min control speed, 28 Volumes, 28

Error messages, 46

WAT charts, 28, 29 Wing box, 15

F568 propeller, 49 FDR, Flight Data Recorder, 52 Flight dynamics, 28 Fortran, 6, 44 Fuel tanks, 9 Go around, 28 Gust response, 28 Linux, 12 London Heathrow, LHR, 44 Matlab, 6, 14, 44 Mean aerodynamic chord, 15 MS Windows, 12 Noise, 32

74