Flight Performance Software FLIGHT - University of 2.4 Cruise drag of the Airbus A320-211 ... * The...

Flight Performance Software

FLIGHT

Antonio Filippone

School of Mechanical, Aerospace and Civil EngineeringThe University of Manchester

United Kingdom

Updated January 2016

Report: AF-AERO-UNIMAN-2014-10

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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 transportairplanes powered by gas turbine engines (e.g. turbofans and turboprops). The main features ofthis system include: geometric modelling, mass properties (including inertias and centre of grav-ity), static trim in air and on the ground, aerodynamics at all flight conditions (including airplanederivatives), propulsion models for the gas turbine engines and the auxiliary power units, propul-sion models for the propeller, flight mechanics and system integration, thermophysics, includingwing icing, tyre temperatures, fuel temperatures in flight, jet blast, manoeuvre analysis (includingflight in a downburst), environmental analysis (including LTO emissions), aircraft noise (includingreal-time noise maps). This report includes a user manual and some examples of output files. Val-idation and verification is a main driver in the development of any sub-system. Issues of accuracyare mentioned briefly, as they are fully addressed in the published literature. Reference is doneto the appropriate technical literature to point out the features of the software. A list of relevantapplications is provided.[This report will updated when the software is upgraded]

Keywords: Airplane Aerodynamics, Aircraft Performance and Stability, Aircraft Noise, AircraftOperations, Gas Turbine Engines, Environmental Emissions, Direct Operating Costs (DOC)

Copyright © A. Filippone, The University of Manchester (2010-2015)

Contents

Listings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1 Introduction 51.1 Polite Notice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2 System Specifications 72.1 Software Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.1.1 Release Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.1.2 Units and Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.2 Airplane Models and Input Structure . . . . . . . . . . . . . . . . . . . . . . . . . . 112.3 Program Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

2.3.1 Caveats and Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132.4 Output Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132.5 Modules and Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2.5.1 Geometry Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142.5.2 Structures and Weight Module . . . . . . . . . . . . . . . . . . . . . . . . . 162.5.3 Aerodynamics Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172.5.4 Propulsion Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192.5.5 Propeller Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192.5.6 Flight Mechanics Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202.5.7 Performance Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212.5.8 Optimisation Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212.5.9 Environmental Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222.5.10 Aircraft Noise Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

3 Guide to User Menu 263.1 Top Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

3.1.1 Performance Charts Sub-Menu . . . . . . . . . . . . . . . . . . . . . . . . . 273.1.2 The WAT Charts sub-menu . . . . . . . . . . . . . . . . . . . . . . . . . . . 293.1.3 Mission Analysis Sub-menu . . . . . . . . . . . . . . . . . . . . . . . . . . . 293.1.4 Aircraft Noise Sub-menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313.1.5 Propeller Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373.1.6 Noise Calculations Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . 373.1.7 Exhaust Emissions Sub-Menu . . . . . . . . . . . . . . . . . . . . . . . . . . 383.1.8 Flight Optimisation Sub-menu . . . . . . . . . . . . . . . . . . . . . . . . . 383.1.9 Manoeuvre Analysis Sub-menu . . . . . . . . . . . . . . . . . . . . . . . . . 393.1.10 Trim Analysis Sub-menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393.1.11 Direct Operating Costs Sub-Menu . . . . . . . . . . . . . . . . . . . . . . . 39

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3.2 Batch Jobs (Linux/Unix Version) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413.3 Other Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

3.3.1 How to Restart a Footprint Analysis . . . . . . . . . . . . . . . . . . . . . . 443.3.2 Aerodynamic Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 443.3.3 Propulsion Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.4 Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4 Guide to Propeller Code 464.1 User Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

5 Case Studies 505.1 Aerodynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 505.2 Airframe-Engine Integration: SAR Charts . . . . . . . . . . . . . . . . . . . . . . . 515.3 Thermo-physics: Simulation of Fuel Tank Temperature . . . . . . . . . . . . . . . . 515.4 Aircraft Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 525.5 Operational Performance: Payload-Range . . . . . . . . . . . . . . . . . . . . . . . 525.6 Longitudinal Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 535.7 Propeller Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

6 Selected Output Files & Data 586.1 AEO Take-off of an A320 Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

6.1.1 AEO Climb of an Airbus-A320 Airplane Model . . . . . . . . . . . . . . . . 606.1.2 Cruise Performance of an Airbus A320 Airplane Model . . . . . . . . . . . . 616.1.3 En-Route Descent of an Airbus A320 Airplane Model . . . . . . . . . . . . 626.1.4 Mission Report of an A320 Model . . . . . . . . . . . . . . . . . . . . . . . 63

6.2 Nomenclature & Conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

A List of User-Defined Parameters 71

Index 74

Listings

2.1 Version of Software System and Database . . . . . . . . . . . . . . . . . . . . . . . 102.2 Wetted Areas of the G550 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162.3 Mass distribution of the G550 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172.4 Cruise drag of the Airbus A320-211 . . . . . . . . . . . . . . . . . . . . . . . . . . 192.5 Noise stacks options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243.1 Analysis Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263.2 Performance charts options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 273.3 Take-off options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293.4 Performance Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293.5 Mission Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293.6 Updating Atmospheric Winds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303.7 Updating Mission Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303.8 Aircraft Noise Sub-Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323.9 Aircraft Noise Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333.10 Noise Footprint Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 333.11 Options for Calculating footprints from multiple movements . . . . . . . . . . . . 343.12 Template of directivity file . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353.13 Noise sub-options menu, propagation models . . . . . . . . . . . . . . . . . . . . . 363.14 Nose sub-options menu, propagation models . . . . . . . . . . . . . . . . . . . . . . 363.15 Output data in noise breakdown files . . . . . . . . . . . . . . . . . . . . . . . . . . 373.16 Aircraft Emissions Sub-Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383.17 Flight Optimisation Sub-Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 383.18 Aircraft Trim Sub-Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393.19 DOC File Notes (refer to Listing 3.20) . . . . . . . . . . . . . . . . . . . . . . . . . 393.20 DOC File (template) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403.21 Batch job file for noise footprints . . . . . . . . . . . . . . . . . . . . . . . . . . . . 413.22 Batch job file for noise sensitivity analysis . . . . . . . . . . . . . . . . . . . . . . 413.23 Batch job file for noise calculations . . . . . . . . . . . . . . . . . . . . . . . . . . 423.24 Output of batch job file for noise calculations (cost functions.txt). . . . . . . . 423.25 Typical configuration file aerotool.cfg. . . . . . . . . . . . . . . . . . . . . . . . 443.26 Typical configuration file enginetool.cfg. . . . . . . . . . . . . . . . . . . . . . . 454.1 Propeller Analysis Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464.2 Non-axial flow performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 474.3 Operational conditions for propeller noise (default) . . . . . . . . . . . . . . . . . 484.4 Propeller design data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49A.1 User-Defined Parameters, Part 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71A.2 User-Defined Parameters, Part 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71A.3 User-Defined Parameters, Part 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

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Chapter 1

IntroductionIn this document we give a brief description of the comprehensive flight mechanics programFLIGHT. Some relevant publications on this program are listed at the end of this document.Publications exist on the general framework1;2;3;4, on aircraft performance5;6;7;8;9, on aircraftnoise10;11;12;13;14;15;16;17 and environmental emissions18;19.

Additional bibliography related to the theoretical background of this software is given in thepapers and books cited. This report is not a theory manual. Although the program is fullymulti-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 bestfuel load in the presence of fuel price differentials (tankering) and costs index (based on time, fuelcosts 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

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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 systemssuch as tyres, or with CFD codes for wing aerodynamics and jet dispersion, or with optimal controlprograms to optimise flight trajectories with a variety of cost functions.

The FLIGHT software, in its current form, is not suitable for preliminary aircraft design. Thereis number of computer codes available for this purpose. The number of inputs required for anygiven aircraft is so large (hundreds of parameters, in fact) that it would not be possible to con-template multi-disciplinary design. FLIGHT is being fully documented and demonstrated in thetechnical literature, with a growing number of cases. Examples are reported in Chapter 5. How-ever, simple trade-off studies can be carried out with ad-hoc routines, that allow, inter alia, theanalysis of morphing wings20, the parametric effects of wing areas and structural weights, andsensitivity analysis of component wetted areas.

The development of an aircraft model relies on official documentations for the airplane, includ-ing 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 meantrue, and in fact a good deal of cross-analysis is required to extract quantitative data of engineeringuse. 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 aircraftflight performance, through physical principles and rigorous validation across disciplines. In thiscode, there is a departure from closed-form solutions of classical mechanics, and a widespread useof numerical methods. We have gained considerable experience in data analysis, verification ofperformance/design data, sensitivity problems, propulsion integration and more*. The program iswritten in Fortran 95, with some interface tools written in Matlab. It is optimized for numericalperformance. The program runs as an executable under Linux and Windows 7 and above. Onrequest, 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 inthe open domain. This information includes the Type Certificates (airplane, engines, propellers),airworthiness data, data published by the manufacturers through their websites and the relativedocumentation; periodic publications by the manufacturers, industry documents, conference pro-ceedings, technical papers, contract reports, etc. No proprietary information is disclosed.

The Author cannot accept responsibility for any action resulting in damage, accident or loss asa consequence of using the FLIGHT program. None of the graphs and figures can be used to makea final judgement on any aircraft, any manufacturer, any flight, any service or any design. If youare in doubt, please consult the Author, seek professional advice or use the performance programsfrom 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 summaryof typical user parameters for a complete mission calculation is given in Table 2.1. The codecontains modules for geometry and the reconstruction of the airplane; for aerodynamics, propulsion,stability, performance, noise, thermodynamics, tyre dynamics, and more. The “Database” blockcontains external data that are required for a variety of tasks, and are separate from the airplaneinput deck. We are convinced that this is the most comprehensive approach to performanceavailable today.

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

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2 System Specifications 8

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

Taxi-out Roll speed constantRoll distance to runwayIdle timeRoadway temperature

Take-off Tentative Flap setting const/variableEngine derating

Climb to ICA Engine derating const/variableKCAS of 1st segment can be optimisedFinal KTAS of 2nd segment can be optimisedKCAS of 3rd segment can be optimised

Cruise Climb procedure between FLSwitch procedure between FLCG shift and trim procedure automatic at cruise

Descent Descent to FL specified by final KIASKCAS of 2nd segment to 10,000 feetKCAS of 3rd segment to 1,500 feet

Final approach Glide slopeSeveral flight control parameters steep approach

Landing Stopping procedure (ailerons, brakes, etc.)Flap settings const/variableRoadway temperature

Contingency Diversion parametersHolding parametersReserve policy

Operational Data On-board passenger services kg/paxBaggage allowance kg/paxBulk cargo ≥ 0Initial CG position

Atmosphere Air temperaturesWinds at all flight segments

Noise abatement Climb-out procedure constraintsFinal approach flight path constraints

Other parameters Aerodynamic deterioration (profile drag)Engine deterioration (fuel flow)

The [Noise] module can run almost as a stand-alone code, if one has a suitable aircraft tra-jectory. A special format is required; this is not available in the demo version. In practice, it ispossible to map an arbitrary flight trajectory to an airplane model and calculate the correspondingnoise 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 componentsand the most accurate numerics to simulate effects such as atmospheric propagation, ground effectand the effects of wind shear, with arbitrary wind directions and arbitrary humidity levels.


Figure 2.2 shows a breakdown into sub-systems, which are modelled separately, and thenassembled 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 tovalidated 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 flightenvelopes and all the functional details of the engine, including design limitations, database ofemissions, design operation point, etc. The geometry/bitmap model refers to the actual geometry


FLIGHT

Airframe

Engine

FLIGHT

PropNoise

Propeller

Database

APU

Model Software

Figure 2.3: Software version control.

of the aircraft stored in a bitmap file. Parsing of this file is done through the [Geometry] modelof 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.

Listing 2.1: Version of Software System and Database

FLIGHT Vers ion : 6 . 8 . 1Rev i s ion : aDatabase : 1 9 . 3 . 3

PropNoise : 3 . 8 . 1Build : 3984/44.3%

Licensed to : Owner

Airp lane : Airbus A320−211; Vers ion 1 . 2 . 2Engine : CFM56−5C4P ; Vers ion 3 . 1 . 1APU : 131−9

2.1.2 Units and Dimensions

The code works this international units (SI) whenever possible. Unfortunately, aviation still prefersimperial units, and unless conversions are done, it is impossible to compare data. Although the useof kg (for mass) and Newton (force) have become increasingly widespread, pounds and feet stillgovern the official documents. For this reason, sometimes the output data are printed in imperialunits, 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. Thepound [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 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 adatabase needed to reconstruct the full geometry of the airplane. [We can provide additionalairplane models.]

� Engine Deck, with data and certified limitations, and a series of steady-state performancecharts 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 to90 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, andflight 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 thereconstruction 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 arealistic accuracy. Although a CAD model would be needed, data generally available do not allowsufficient 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 thecross-section of the ATR72-500 model.

Normally, the atmospheric data are included into an operation file, which collects data suchas 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; afile 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 airfoilsthat are scaled for the case under study.

A complete flowchart of the airplane model is shown in Figure 2.6. These data sets are collectedin ./Airplanes/Airplane name/..


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

x, m

y,m

-2 -1 0 1 20

1

2

3

4

Cylindricfuselage

Wing-Body

Body Fairing

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 executablefile called go in the working directory. To run, enter command ./go.

� MS Windows zipped file flight*.zip. Unzip to self-install. The executable is calledflight*.exe in the working directory.


Bit d t Limitations

Airframe Engine

Bitmap data

Limitations

Limitations

Configuration

FLT EnvelopeAERO Derivs

FLIGHT

Blade Sect

Propeller

Blade Sect.

APUAERO Polars Configuration

FLT Envelope FLT Envelope

Figure 2.6: Flowchart of a complete airplane model.

After running successfully, all output files are moved into the ./Outputs folder. If the programhas 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 files to the appropriate location. Notethat existing files are overwritten. Old files must be stored to prevent results being lost. The usershould get acquainted with the output data, since more than 100 different files are available foranalysis, 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 possibili-ties; the user should get acquainted with the limitations of the flight model when the envelope ofthe airplane is exceeded. In most cases, there is a clear error message on screen to advise the userof possible causes of errors and/or limitations. When the error is not recognized, it is possible thatthe program will terminate by aborting the run.

The FLIGHT software has been developed in an academic environment. It has a strong theoret-ical 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 particularapplication in industry, engineering or education. The code should only be used by professionalswho 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 thesefiles 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 intoseveral sub-folders, as described below:

� All report files, called report*.out are moved to./Outputs/Airplane/Reports/..


� 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, wemake 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 higher-order interpolation. In particular, the module provides the sub-components listed in the nextpage. 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.


The latter element is also part of the propulsion module. For all the components, the moduleprovides 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 aerody-namic model. Wing areas are calculated according to three different methods. The user may wantto 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.

X-coordinate from nose, m

span

wis

ech

oord

inat

e,m

24 25 26 27 280

1

2

3

4

1

2 3

4

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 per-form calculations that are strongly dependent on the MAC. Such cases include at least longitudinaltrim conditions and cruise drag. Some manufacturers refer to a “reference chord”, rather than aMAC, 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 controlpoints (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 thismodel, raw data such as “wing area” or “wing span” are not used. The resulting parameters arecompared, if possible, with the manufacturer’s official data. There is no other practical way ofdescribing the geometry of the airplane in absence of CAD drawings. However, a considerableamount of detail can be extracted, including the wetted area breakdown, the cross-sectional areadistribution, position of reference points, etc. Figure 2.7 shows the construction of the horizontaltail system of the ATR72-500. Listing 2.2 shows a summary of wetted areas calculated for theGulfstream G550.


Listing 2.2: Wetted Areas of the G550

Airplane = Gulfstream G550 ; Vers ion 1 . 0 . 1Engine = BR710A1−10 ; Vers ion 4 . 1 . 1APU = Re−220 ; Vers ion 1 . 0 . 0

Wetted Areas Summary−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Fuse lage = 166.91 [m2] , 33 .65 %−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Nose = 22.82 [m2] , 4 .60 %Center = 108.95 [m2] , 21 .96 % [ co r r e c t ed f o r root wing s e c t i o n ]

Aft = 29 .64 [m2] , 5 .97 % [ co r r e c t ed f o r root t a i l s e c t i o n ]** [Wing−body blend ] = 5 .49 [m2] , 1 .11 % [ inc luded in c en t r a l s e c t i o n ]**

−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−Wing = 190.67 [m2] , 38 .43 % [ co r r e c t ed f o r f l a p racks , 0 m2 ]

Wing t i p s = 0.00 [m2] , 0 .00 %Winglets = 5 .21 [m2] , 1 .05 %

Hor i zonta l Ta i l = 47 .76 [m2] , 9 .63 %Ve r t i c a l Ta i l = 31 .29 [m2] , 6 .31 %

Nace l l e s = 45 .68 [m2] , 9 .21 %Pylons = 8.57 [m2] , 1 .73 %

Flap racks = 0.00 [m2] , 0 .00 %−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Total wetted area = 496.09 [m2] , 5340 . [ f t 2 ]Wet area/Wing Area = 4.712Wing Area/Wet area = 0.212

Gross ( wetted ) f u s e l a g e s h e l l area = 162.84 [m2]

Wetted Areas ( other components , est imated )−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Al l Flaps = 14 .6 [m2] , 2 . 9 %Al l S l a t s = 0 .0 [m2] , 0 . 0 %

Al l S p o i l e r s = 11 .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 inertiaof 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)


� 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 = Gulfstream G550 ; Vers ion 1 . 0 . 1Engine = BR710A1−10 ; Vers ion 4 . 1 . 1 ; APU = Re−220

Airp lane Mass/Weight Report−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

She l l Fuse lage = 3453.6 [ kg ] 16 .39 [%]Nose Sec t i on = 158 .9 [ kg ] 0 . 75 [%]

Centra l Sec t i on = 3088.4 [ kg ] 14 .66 [%]Ta i l Sec t i on = 206 .3 [ kg ] 0 . 98 [%]

Fuse lage f l o o r = 243 .4 [ kg ] 1 . 16 [%]

Wing System = 3784.1 [ kg ] 17 .96 [%]H−Tai l System = 607 .3 [ kg ] 2 . 88 [%]V−Tai l System = 324 .1 [ kg ] 1 . 54 [%]

Landing Gear System = 1630.4 [ kg ] 7 . 74 [%]Nose Landing Gear = 271 .5 [ kg ] 1 .29 [%]

Tyres = 50 .0 [ kg ] 0 . 24 [%]Ro l l i ng s tock = 100 .0 [ kg ] 0 . 47 [%]

S t ruc tu r e s = 171 .5 [ kg ] 0 . 81 [%]Main Landing Gear = 1368.7 [ kg ] 6 . 50 [%]

Tyres = 90 .0 [ kg ] 0 . 43 [%]Ro l l i ng s tock = 279 .0 [ kg ] 1 . 32 [%]

S t ruc tu r e s = 999 .7 [ kg ] 4 . 74 [%]

Propuls ion System = 5812.1 [ kg ] 27 .58 [%]Engines = 3702.0 [ kg ] 17 .57 [%]

Nace l l e /Pylons = 2110.1 [ kg ] 10 .01 [%]Other = 0 .0 [ kg ] 0 . 00 [%]

APU mass = 109 .0 [ kg ] 0 . 52 [%]

Furn i sh ings = 840 .0 [ kg ] 3 . 99 [%]Seats = 588 .0 [ kg ] 2 . 79 [%]Other = 210 .0 [ kg ] 1 . 00 [%]

ALL Systems = 4259.5 [ kg ] 20 .21 [%]−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

TOTAL* = 21073.5 [ 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 itis generally not true, there is not enough information in order to make a quantitative assessmentabout their contribution.

Engine geometry details are likewise extracted from photographs, either taken by the Authoror from the public domain (for example: Google images and related websites). As an example, weshow 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 condi-tions. In particular, it provides:


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 A320-211airplane model. This is an extract of a report called report drag.out.


Listing 2.4: Cruise drag of the Airbus A320-211

Maximum Operating Mach number , MMO = 0.820Maximum Dive Mach number , MD = 0.877

Fuse lage Drag Breakdown−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Fl i gh t Alt = 10.058 [km] 33000 . [ f e e t ]Mach = 0.790

Avg Skin CD = 0.00790 42 .1 [%]nose = 0.00186 9 .9 [%] ( Turbulent Nose Cone )

cente r = 0.00398 21 .2 [%] ( Shultz−Grunow)t a i l = 0.00206 11 .0 [%]

−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−Total = 0.01876

Drag counts = 187 .6

P r o f i l e Drag Breakdown−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Fl i gh t Alt = 10.058 [km] 33000 . [ f e e t ]Mach = 0.790

Fuse lage = 0.01876Wing = 0.00499

Tai l p lane = 0.00129Fin = 0.00113

Nace l l e s = 0.00072Pylons = 0.00024

Winglets = 0.00005Excrescence = 0.00125

−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−Total = 0.02870

Drag counts = 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 tempera-ture 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 thepropulsion module.

2.5.5 Propeller Module

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


Mass flow rate, kg/s

Net

th

rust

, kN

200 400 600 800 10000

100

200

300

S/L

2 km

4

6

8

10

12

14

Figure 2.9: Net thrust as function of mass flow rate for the GP-7200 operating at standard atmo-sphere. 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 pro-gram 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 andprovides on output a full account of exhaust emissions per passenger (pax), per-passenger/per n-mile, etc. From the point of view of stability analysis, the program only calculates static stabilityconditions. 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 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) andOne 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 parametersand 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.


� 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 Machnumber.

� Best cruise program (selection of flight levels, shift between flight levels, climb proceduresbetween 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 tothe 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 2.10shows the analysis of carbon-dioxide emissions for a model Airbus A320-211 with CFM56 turbofanengines.


Stage length, n-miles

CO

2/pa

x, k

g

CO

2/pa

x/nm

, kg

1000 2000 30000

200

400

600

0.12

0.16

0.2

0.24CO2/paxCO2/pax/nm

Figure 2.10: Carbon-dioxide emissions of an Airbus A320-211-CFM versus stage length at a fixedpassenger 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.


� 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 Mult ip l e A i r c r a f t Movements−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

S ing l e Take−o f f AND Landing [ 1 ]Mult ip 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 externally-generated trajectories, if they fulfill certain format requirements. The source components includedin 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


The [Noise-Propagation] sub-module includes all the routines that are used to calculatethe external effects on the noise source. These are: atmospheric absorption, atmospheric thermo-physics (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 areused: 1.) Rasmussen-Almgren method, extended with numerical improvements for long-distancepropagation; 2.) ray tracing methods; 3.) ANSI lateral propagation correction (optional).

At present, a system analysis indicates that their inclusion would change the overall resultby a value that is lower to the system’s inaccuracy. Validation of separate parts of the enginenoise is available, and some is discussed later in this note. As mentioned earlier, there is a sub-module 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 (A-corrected maximum sound pressure level); TAUD (time-audible); awakening probability func-tion. Time-dependent noise signals include the OASPL (overall sound pressure level), raw andA-weighted, for each individual noise component, for the propulsive contributions and for theairframe contributions.

Chapter 3

Guide to User Menu

A number of user-menus are available to change some (not all) problem parameters. Not all op-tions described are available in the demo version. We start from the top level and proceed towardthe various sub-menus.

When the aircraft is loaded, FLIGHT uses the database that accompanies the software. FLIGHTloads 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 thegeometrical reference quantities. Then it loads the engine model and other data, and performsvarious parameter initialisations. In the process, it prints out several output files in the workingdirectory. Once all this is done (it may take a few seconds to complete), the program is ready to go.

Listing 3.1: Analysis Options

Analys i s Options (Top l e v e l )−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−Performance Charts [ 1 ]Miss ion Ana lys i s [ 2 ]A i r c r a f t Noise [ 3 ]Exhaust Emiss ions [ 4 ]F l i gh t Optimizat ion [ 5 ]Maneuver Ana lys i s [ 6 ]Trim Analys i s [ 7 ]D i r ec t Operating Costs [ 8 ]U t i l i t i e s [ 9 ]

Exit /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 27

3.1.1 Performance Charts Sub-Menu

By choosing Option [1] in the top-level menu (Listing 3.1), the user is pointed to a sub-menu whichshows the main performance charts that can be calculated with the FLIGHT code. These optionsshould 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 aboutOption [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 Envelopes [ 3 ]F l i gh t Envelopes [ 4 ]

P rope l l e r [ 5 ]WAT (AEO take−o f f ) [ 6 ]Balanced F i e ld Length [ 7 ]Payload−Range [ 8 ]Economic Mach no . [ 9 ]CG E f f e c t s [ 1 0 ]Buf f e t Boundary [ 1 1 ]Spec . Excess Power [ 1 2 ]Go−Around Charts [ 1 3 ]Atm−Speed Charts [ 1 4 ]Holding Speeds [ 1 5 ]Max Descent Rates [ 1 6 ]

V−n diagram [ 1 7 ]Climb Polar [ 1 8 ]Min . Control Speed [ 1 9 ]Gust Response [ 2 0 ]Long i tud ina l dynamics [ 2 1 ]A i r c r a f t volumes [ 2 2 ]


[1] This option calculates the aerodynamic coefficients of the airplane, and determines aerody-namic charts as function of weight, altitude, centre of gravity position, etc. All the outputfiles should be moved to the output sub-folder ./Charts.

[2] This option generates specific-air-range charts, for both AEO and OEI conditions, over thefull range of altitudes, weights and atmospheric conditions.

[3] This option generates engine performance envelopes at the full range of atmospheric temper-atures and altitudes, for specified flight Mach number; the Mach number is set by the useras 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 propellercharts 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 anumber of default options, the user is prompted to a change of operational parameters. Thisis 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/eco-nomical 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 onlyapproximate.

[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 varietyof situations, including OEI. Several paramers can be changed by the user.

[14] This option generates some charts containing relationships between CAS, TAS, EAS, Machnumber 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 inidle 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 altitudesfrom 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 con-trol 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 definedby 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 ofthe airplane subject to a step input of the elevator. Both short-period and long-period ofmotion (phugoid) solutions are provided. All data, including undampted natural frequencyand damping ratio are in the output files.

[22] Volumes: This option allows the calculation of aircraft volumes (fuselage, wing, horizontaland vertical tail, etc.)

3 User Guide 29

3.1.2 The WAT Charts sub-menu

The Weight-Altitude-Temperature charts of a take-off are established from the performance sub-menu, which points to the following listing.

Listing 3.3: Take-off options

Change Take−o f f Data−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Runway cond i t i on s [ 1 ]Tyre−runway s l i p r a t i o [ 2 ]Winds [ 3 ]Air Temperature [ 4 ]Runway gradient , < 2% [ 5 ]Tentat ive f l a p s e t t i n g [ 6 ]CG−pos i t i on , %MAC [ 7 ]Execute Ca l cu l a t i on [ 0 ]

Return [ any key ]

3.1.3 Mission Analysis Sub-menu

This sub-menu appears as follows:

Listing 3.4: Performance Charts

Ai r c r a f t Miss ion Options−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−Fuel Planning [ 1 ]A i r c r a f t Range [ 2 ]

Matrix−Fuel−Plan [ 3 ]Equal−Time Point [ 4 ]


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 amission specified by payload, requested range and other details. The full specifications of thefuel planning are given by the following options:

Listing 3.5: Mission Data

Miss ion Data−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−Required range [ 1 ]Required bulk payload [ 2 ]Required pax load [ 3 ]Winds [ 4 ]Air temperature [ 5 ]Re 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 gh t Params [ 9 ]

Execute [ 0 ]


3 User Guide 30

The parameters in this menu should be self-explanatory, with the exception of Winds [3] andOther Flight Params [9]. With to point [3] in Listing 3.5, the user can change the windspeed 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 theatmospheric boundary layer, and hence the speed of sound gradient, Listing 3.6.

Listing 3.6: Updating Atmospheric Winds

Redef ine Atmospheric Wind P r o f i l e s−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Very unstab le [ 1 ]Moderately unstab le [ 2 ]Neutral [ 3 ]S l i g h t l y s t ab l e [ 4 ]Moderately unstab le [ 5 ]Very unstab le [ 6 ]


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 Miss ion Data−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−Continuous Descent Approach [ 1 ]Pe r f e c t F l i gh t Tra jec tory [ 2 ]Taxi−in time [ 3 ]Taxi−out time [ 4 ]Engine de ra t ing [ 5 ]Time−delay , FLAP deployment [ 6 ]F ina l approach g l i d e s l ope [ 7 ]Runway state , both T.O./ Land [ 8 ]A i r f i e l d a l t i t u d e [ 9 ]Turn in climb−out [ 1 0 ]F l i gh t Level Separat ion [ 1 1 ]Noise a r rays ex tens i on [ 1 2 ]


Description of Listing 3.7

1. The first option commands the aircraft to perform a CDA from the final cruise altitudeto about 1,500 feet above the airfield.

2. The second option, in addition to the CDA, includes a continuous climb to a cruisealtitude 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 con-ditions 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; thetime 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 departureand destination airfield are at the same altitude.

10. Use this option to set the change in heading required in a climb out. The altitude ofthe 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 specifiedfuel load, in addition to similar parameters specified in [Fuel Planning]. Interactively, theuser 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 parametersaround 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-timepoint, e.g. the time required to return to the origin is equal to the time to continue to thefinal 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 ofvalidation have been published17;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 clarifythat a trajectory must be available. As explained further at a later point, the default trajectoriesprinted out by the program are called iface noise*.out. The trajectories have the format shownin 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 externalfile. The second line shows that this is a landing trajectory. The lines below include the following:

MICROLON, MICROLAT, MICROALT = coordinates of microphone/receiverDATE = flight time (various formats possible)Longitude, Latitude, Altitude = coordinates of the airplane’s CGTheta, Phi, Psi = airplane attitude, heading, bank anglesIAS; TAS; Groundspeed = indicated, true and ground speedsThrust, N1 = net thrust and engine speed in percentGear; SlatFlap = landing gear position; slat/flap positionWeight = all-up weightTemperature, Humid, pressure = atmospheric quantitiesWindspeed, Windirection = 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 itis advisable to use the following alternative.

ALLMICRO n

x1 y1 z1 1

x2 y2 z2 2

....

xn yn 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 couldbe 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 /Departure [ 1 ]Ar r i va l /Landing [ 2 ]S i d e l i n e at ICAO/FAR point [ 3 ]Arb i t rary t r a j e c t o r y [ 4 ]Noise Footpr int [ 5 ]Stack ing Patterns [ 6 ]D i r e c t i v i t y Ana lys i s [ 7 ]Options / U t i l i t i e s [ 8 ]Upper l e v e l [ any key ]

3 User Guide 33


1. This option calculates the aircraft noise at a FAR/ICAO microphone, on the basis of anexisting take-off/climb-out trajectory, previously calculated with a mission analysis. Thistrajectory is found in the ./Outputs/project airplane name/. sub-folder; the trajectoryfile is called iface noise takeoff.out, described above.

2. This option calculates the aircraft noise at a FAR/ICAO microphone, on the basis of anexisting approach/landing trajectory, previously calculated with a mission analysis. Thistrajectory is found in the ./Outputs/project airplane name/. sub-folder; the trajectoryfile is called iface noise landing.out, described above.

3. This option calculates the aircraft noise at a FAR/ICAO microphone, on the basis of anexisting approach/landing trajectory, previously calculated with a mission analysis. Thistrajectory is found in the ./Outputs/project airplane name/. sub-folder; the trajectoryfile is called iface noise sideline.out, described above.

4. This option calculates the aircraft noise at an arbitrary microphone, on the basis of an existingapproach/landing trajectory, previously calculated with a mission analysis or prepared byother means. The trajectory file is found in the ./Outputs/project airplane name/. sub-folder.

5. This option calculates the noise footprint, either on approach or take-off, on a carpet definedby the user, or on a carpet prepared by other means, who is prompted to Listing 3.9.

Listing 3.9: Aircraft Noise Options

Noise Footpr int : S e l e c t t r a j e c t o r y−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Takeof f /Departure [ 1 ]Approach/Landing [ 2 ]Departure + Landing [ 3 ]Ground Prope r t i e s [ 4 ]


There is the possibility of changing the ground properties (for fixed ground impedance), byselecting 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

Noise Footpr int : S e l e c t Grid−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Se l f−generate g r id ( d e f au l t ) [ 1 ]Read ex t e rna l g r id ( a i r f i e l d ) [ 2 ]


3 User Guide 34

If Option [1] is selected, the user must enter: 1.) x-size of the noise carpet (parallel toflight direction); 2.) y-size of the noise carpet (normal to flight direction). Then the useris prompted to a choice of grid resolutions: coarse, medium (recommended) and fine (CPUintensive). 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 largegradients of a specified noise metric. The calculations can be time consuming, because theyrequire 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 ignoreatmospheric winds (Yes/No). In the affirmative, some execution speed can be gained. CPU-intensive means at least overnight calculations in absence of atmospheric winds, and weekendin the presence of strong winds.

If Option [2] is selected, the user must enter the file name of the grid, residing in the workingdirectory. This file can be an ASCII data file or a csv-file (comma-separated). Grid coordi-nates can be in a local reference system (units: metres), or GPS coordinates. An example ofthis data file is shown below.

GPS ! data are in GPS coordinates

conversion YES ! conversion to local refererence system required if YES

53.3615 -2.259 ! coordinates of reference point at airfield if YES

78 ! airport altitude [m]

invert NO ! inversion of matrix required if YES

rotate YES ! align grid along long axis

106 53 ! nxgrid nygrid

LATITUDE LONGITUDE SURFACE Legend

53.28050015 -2.370239699 G A Asphalt (dry)

53.28155556 -2.368056271 G B Built-up area (dry)

53.28261096 -2.365872843 G C Concrete (dry)

53.28366637 -2.363689415 G F Forest (dry)

53.28472178 -2.361505987 G G Grass (dry)

53.28577719 -2.359322559 G S Snow (wet?)

53.28683260 -2.357139132 F T Tarmac (dry)

53.28788801 -2.354955704 G W Water (wet)

Figure 3.1 shows selected points at London Heathrow. Latitude and longitude coordinatesare 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 selectionof approach and take-off trajectories for the same airplane, as well as the time separationbetween flights (this separation is given in seconds). On output, the program produces *.avifiles 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 Mult ip l e A i r c r a f t Movements−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

S ing l e Take−o f f AND Landing [ 1 ]Mult ip l e Take−o f f AND Landings [ 2 ]


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. Onlyone 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 orat the brake on the ground. In the latter case, only engine noise is calculated. The programrequests the name of a data file, which contains the essential data for the calculation. Thesedata are:

Listing 3.12: Template of directivity file

LATERAL d i r e c t i v i t y type Unit ! LATERAL/POLAR/FRONTAL only

200 . RADIUS [m] ! r ad iu s o f microphones cente red at CG−5. z below CG [m] ! p o s i t i o n o f r e f . c i r c l e above/below CG

457 . A l t i tude [m] ! f l i g h t a l t i t u d e ( ground at z = 0)1 .9 Theta [ degs ] ! p i t ch a t t i t ud e0 .0 Phi [ degs ] ! bank a t t i t ud e / ang le0 . 0 Psi [ degs ] ! heading140 .3 KTAS [ kt ] ! t rue a i r speed , knots

1 LGear ! land ing gear p o s i t i o n : 1 = deployed5 iS l a tF l ap ! Flap/ S la t s e t t i n g = 0 , 1 , 2 , 3 , . . .55 .9 N%1 [%] ! eng ine rpm ( unused ; p r e f e r s f u e l f low )0.29879 f f l ow [ kg/ s ] ! f u e l f low ( a l l eng ine s )0 . 0 WindSpeed [m/ s ] ! wind speed0 .0 WindDirection [ degs ] ! wind d i r e c t i o n70 .0 Re la t ive humid i ty [%] ! r e l a t i v e humidity o f a i r0 . dTemp [K] ! dTemp = 0 −> standard day50000 . mass [ kg ] ! a l l−up mass ( cu r r en 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 orFRONTAL. An error message is issued otherwise. The program returns the OASPL(dB), andthe 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 ofwind. 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 operationalparameters. If this option is set, when returning to the main noise menu (Listing 3.8), thetake-off [1] and landing [2] calculations will use a perturbation data file in the ./Airplanessub-folder.

These calculations include sensitivities on about 40 parameters, but are not offered in thedemo version. The full menu of user-options is shown in Listing 3.13. The acoustic linersboundary layer calculation is set to false by default. This can be toggled by choosing [5] inListing 3.13.

Listing 3.13: Noise sub-options menu, propagation models

Noise Options , U t i l i t i e s and De fau l t s−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Parameter S e n s i t i v i t y Ana lys i s [ 1 ]Ground−Turbulence Prope r t i e s [ 2 ]Inc lude background Noise [ 3 ]Change Noise Propagation Model [ 4 ]Change Noise Source Models [ 5 ]Acoust ic Liner Boundary Layer [ 6 ]Convert Noise Tra jec tory to 2D [ 7 ]Ref ine Noise Carpet/ Footpr int [ 8 ]Toggle topography e f f e c t s [ 9 ]Generate Fly−over t r a j e c t o r y [ 1 0 ]

The background noise is included when toggling option [3]. The program points a questionto the user to change the background noise to a specified spectrum, which must be read froma data file in the working directory. This file contains two columns: frequency and noiselevel. The noise level can be A-weighted or not; the program will sort out the sums after theuser provides the correct information.

It is possible to change some noise models with option [5], although in fact there are somelimitations and the best results are obtained with default models. Considerable work is stillneeded in this area.

Toggling the acoustic liner boundary layer, option [6], forces more demands on the compu-tational efforts, and the program can be sensibly slower.

Note that the background noise is treated as an additional noise source that is added at theend. This implies that the various source contributions are not affected, but the final sumand the integral noise metrics are affected by the background noise. The noise propagationmodels are shown in Listing 3.14. This menu is accessed from Option [8].

Listing 3.14: Nose sub-options menu, propagation models

Noise Propagation Options−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Rasmussen/Almgren method , DEFAULT [ 1 ]ANSI/SAE AIR 5662 , l a t e r a l propag . [ 2 ]Ray t r a c i ng method [ 3 ]


3 User Guide 37

3.1.5 Propeller Noise

The case of propeller-driven airplane is computationally more elaborate, since it relies of an longsequence of events involving flight mechanic calculations. In brief, at each time step, the pro-peller is trimmed to match the flight mechanics equations, and thus will have a required poweror thrust. These parameters form the basis of a propeller trim, which then provides the aerody-namic loads that are finally used by the acoustic solver. An interface file is required; this is calledproponoise.iface, an example of which is shown below. This file is automatically generated.

"Dash8_Q400" Airplane name

"R408" Propeller name

0.1937 Flight Mach number

"landing" Flight condition

7894.1000 0.0000 113.4400 Source Position in ground reference (x,y,z) [m]

6420.4426 0.0000 71.2000 Receiver Position in ground reference (x,y,z) [m]

0.9986 0.0000 -0.0524 Unit vector parallel to propeller shaft

65.7386 0.0000 -3.4500 Vector velocity in ground reference [m/s]

112.0125 Required shaft power [kW]

0.1000E-02 Max Tolerance on propeller trim conditions

.true. Propeller trim required

END

3.1.6 Noise Calculations Outputs

On output, this module provides a very detailed analysis of the airplane performance. There areat least three types of outputs:

1. Noise breakdown files: these are printed for each ground microphone and for each flighttrajectory. The output file contains the main flight parameters as well as the following noisemetrics: OASPL (overal sound pressure level); OASPLa (airframe OASPL); OASPLe (engineOASPL), LA[dBA] (A-weighted OASPL), PNL (perceived noise level), PNLT (tone-correctedperceived noise level), Loud (noise loudness).

2. Noise trajectory files: in addition to the basic flight parameters, these files include theengine state over the full trajectory.

3. Noise report files: these reports include the spectral components of each contribution (splitbetween 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 . SRCt [ s ] RECt [ s ]b . x [km] y [km] s [km] h [km] h [ k f t ]c . r [km] theta KTASd . LGear iSF

e . Wing HSTAB VSTAB SLAT FLAP NLG MLGf . FANi FANe FAN LPC HPC COMB HPT LPT JETg . APUC APUJ

h . OASPL OASPLa OASPLe eCORE PNL[dB ] PNLT[dBA] LA[dBA] Loud [dBA]

Although all these parameters are on a single row, here they are discussed on the basis of theirdifferent 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 callpoints to the following set of sub-options.

Listing 3.16: Aircraft Emissions Sub-Menu

Ai r c r a f t Emiss ions Deck−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Exhaust Emiss ions vs range [ 1 ]Cont ra i l Ana lys i s [ 2 ]



1. This option allows the calculation of aircraft emissions corresponding to a given payload andpassenger 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-menuis available to input key operational requirements.

2. This option allows the simulation of aircraft contrails and a number of related emissionscharacteristics; 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 currentversion of FLIGHT has the features in listing 3.17.

Listing 3.17: Flight Optimisation Sub-Menu

Optimisat ion Deck−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−Minimum Climb−Fuel [ 1 ]Optimum Climb between F l i gh t Leve l s [ 2 ]Fuel Tankering Ana lys i s [ 3 ]


1. This option estimates the minimum climb fuel to a specified initial cruise altitude, for spec-ified 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 39

3.1.9 Manoeuvre Analysis Sub-menu

In the current version of the software there is only one option here: the calculation of aircraftlanding in a downburst. An option menu appears to set the main characteristics of the downburstwind. 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 flightmanoeuvre inside a downburst is required, the program requests the minimum distance fromthe core of the downburst, then it automatically sets the airplane on a flight path through thedownburst 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 minimumcontrol speed on the ground. An option menu appears to set the main characteristics to calculatethe minimum control speed. These options are not active in the DEMO version.

Listing 3.18: Aircraft Trim Sub-Menu

Ai r c r a f t Trim Deck−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−Minimum Control Speed in Air , VMCA [ 1 ]Minimum Control Speed on Ground , VMCG [ 2 ]


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 mustreside in the working directory, where the executable runs. The reason why a file name is requiredat 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. Forconvenience, we report below a template of such a file, with the description of the case data. Thisfile 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 verifythese numerical data, except the number of cycles required for stage length, block time and anynegative entry; all data must be consistent and reasonable.

If something is wrong on input, the program will report the line number relative to the lastrecord read successfully. For example if last record = currency, there must be something wrongin the aircraft price data (one line below).

Listing 3.19: DOC File Notes (refer to Listing 3.20)

a . man hour i n f l a t i o n i s the same as ” c r ew p r i c e i n f l a t i o n ”b . l abou r r a t e i n f l a t i o n i s the same as ” c r ew p r i c e i n f l a t i o n ”c . a l l o ther c o s t s ( spare parts , e t c . ) are i n f l a t e d by the same amountd . i f no OIL SHOCK i s expected , assume 1 . 0 ; the year ( next record ) i s ignorede . 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 be t t e r e s t imate ; may

ove r r i d e data abovef . i f you change the s tage l ength and/or the bulk cargo , you must repeat miss ion

ca l cu l a t i on , because f u e l burn and block time w i l l be d i f f e r e n tg . the ove r r i d e parameter must be t rue or f a l s e . Error i s encountered otherwi s e ;

t h i s parameter i s overr idden i f the number o f c y c l e s i s not ach i evab l e .h : commuter s e r v i c e (X < 250 n−mi le s ) ; i n t e r n a t i o n a l (250 < X < 2500) ;

i n t e r c o n t i n e n t a l (X > 2500)

3 User Guide 40

Listing 3.20: DOC File (template)

”A. Fi l ippone , on 15 August 2012 ; Pro j e c t = G550 DOC” ! don ’ t f o r g e t t i t l e”G550” a i r p l an e name

”Do l l a r s ” currency ( data below in Do l l a r s )

47d6 a i r c r a f t p r i c e ( in above currency )0 .67 f u e l pr ice now ( f u e l p r i c e TODAY) ( per kg )1 .0 f u e l p r i c e i n f l a t i o n (% per year , AVERAGE)25 . f u e l p r i c e h ike on s p e c i f i e d year : OIL SHOCK (%)2 year at which OIL SHOCK i s expected1 .2 insurance , based on a i r c r a f t a c tua l va lue (% per year )

0 . 5 s p a r e s p r i c e 1 ( a i r f rame , land ing gear , t y r e s ) (% on Year 1)0 .5 s p a r e s p r i c e 2 ( engine , APU, l ub r i c an t s ) : (% on Year 1)0 .1 s p a r e s p r i c e 3 ( av i on i c s / systems / pax s e r v i c e s ) (% on Year 1)

20 . l i f e t i m e85 . d ep r e c i a t i on over l i f e −time (% of i n i t i a l co s t )70 . f i n anc i ng (% o f i n i t i a l co s t )4 . 0 i n t e r e s t r a t e (%)10 years o f mortgage ( i n t e g e r number )

55000 . c rew pr i ce1 , p i l o t s ( f u l l time/ p i l o t / year )25000 . c rew pr i ce2 , f l i g h t attendants ( f u l l time/ s t a f f / year )

2 . c r ew p r i c e i n f l a t i o n (% per year )80 . o f f s t a t i o n p r i c e ( hote l s , e t c ) ( per person / night )

75 . l abour ra t e1 , powerplant (man−hour )40 . l abour ra t e2 , in−house maintenance (man−hour )65 . l abour ra t e3 , contrac ted out (man−hour )

50 . man hour1 , powerplant ( per 1 ,000 c y c l e s )50 . man hour2 , in−house ( per 1 ,000 c y c l e s )50 . man hour3 , cont rac ted out ( per 1 ,000 c y c l e s )

300 . l and ing charge s , a i r p o r t f e e s ( per movement )200 . ground handl ing c o s t s ( per movement )

50000 . r e cu r r en t t r a i n i n g c o s t s ( f l i g h t crew/year )50 . f l i g h t s e r v i c e c o s t s : ca t e r ing , marketing ( pax/ f l i g h t ; year 1)

600 c y c l e s ( 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 type see note [ h ]. t rue . ov e r r i d e ” c y c l e s ” i f t rue ; keep above value i f . f a l s e .4500 . s tage length , n−mi l e s ( average )

70 . average l o a d f a c t o r ( pax/ s e a t s )

16200 . miss ion f u e l burn *Prev ious ly c a l c u l a t ed * ( kg )670 . b lock time * Prev ious ly c a l c u l a t ed * (min )

100 . cargo / f r e i g h t ( kg/ f l i g h t ) *Unused5 .25 c a r g o p r i c e ( currency /kg ) *Unused

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

3 User Guide 41

3.2 Batch Jobs (Linux/Unix Version)

Some computations require too much time to be monitored on screen. Therefore, we have developeda 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 ofpoints, 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, containingthe basic commands to execute the job. An example of such file is described in Listing 3.21.

x[m]

y[m

]

-5000 0 5000

-2000

-1000

0

1000

2000

3000sigmae: 5.0E+05 1.0E+06 1.5E+06 2.0E+06 2.5E+06 3.0E+06 3.5E+06 4.0

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 an e name” turbofan ” engine type

12 a i r p l an e index” land ing ” t r a j e c t o r y type ; uses d e f au l t f i l e in . / Pro j e c t s /Airp lane” ex t e rna l ” g r id type”Heathrow . csv ” g r id f i l e name. t rue . i gno r e atmospher ic winds i f t h i s f l a g i s t rue

Noise Sensitivity Analysis. As in the previous case, several hours may be required to runsensitivity cases to uncertain parameters, on single and multiple microphones. Currently, we usein 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 airplanesrequire an inner loop to provide the trim equations for the propeller and the flight mechanics. Anexample 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 ogn i s e t h i s f i l e” n o i s e s e n s i t i v i t y ” type o f c a l c u l a t i o n reques ted”Dash8 Q400” a i r p l an e name” turboprop” engine type2 a i r p l an e index ; cu r r en t l y ** hard−coded **

” land ing ” t r a j e c t o r y type ; uses de f au l in . / Pro j e c t s /Airp lane” ex t e rna l ” 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 torun 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. Theconfiguration 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 ogn i s e t h i s f i l e’ no i se ’ type o f c a l c u l a t i o n r equ i r ed ; code r e c o gn i s e s t h i s keyword’ A320 200 ’ a i r p l an e name’ turbofan ’ eng ine type

3 a i r p l an e index ; t h i s i s cu r r en t l y ** hard−coded **

’ landing ’ t r a j e c t o r y type : land ing or t a k e o f f’ de fau l t ’ pa r s e s d e f au l t f i l e in . / Pro j e c t s /Airplane name/Outputs/. t rue . i gno re atmospher ic winds i f t h i s f l a g i s t rue

Trajectory optimisation is to be carried out by using the standard trajectory interface. It islikely that the engine data are not available in such a context; if the engine data are indeed notavailable, the respective columns will be filled with zeroes or negative numbers. The programruns a check to verify that the engine rpm (N%1) is always positive. If N%1 < 0 in at least oneinstance, the program interprets this case as one of trajectory optimisation with missing enginedata. 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) tothe 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 filecontains selected noise metrics and exhaust emissions, which can be used, in isolation or in com-bination, to determine a cost function for trajectory optimisation. An example of such output isgiven below. Data are printed as e16.8 to allow for further numerical analysis without loss ofprecision.

Listing 3.24: Output of batch job file for noise calculations (cost functions.txt).

# Pred icted environmental emi s s i ons ; generated by FLIGHT V. 7 . 4 . 7# SECTION 1 : Noise Emiss ions

0.13533690E+03 F l i gh t time [ s ]0 .90693171E+02 EPNL[dB ]0.85670246E+02 SEL [dB ]0.65492679E+02 LAeqT [dBA]0.84192493E+02 SPLmax [dB ]0.80448439E+02 LAmax[dBA]0.83894571E+02 SPLfmax [dBA]0.77839573E+02 SPLemax [dBA]

# SECTION 2 : Exhaust Emiss ions0.21620479E+02 Fuel burn [ kg ] , below 3 ,000 f e e t AGL0.68234231E+02 CO2[ kg ] below 3 ,000 f e e t AGL0.75008671E+03 CO [ gr ] below 3 ,000 f e e t AGL0.45244779E+03 NOx[ gr ] below 3 ,000 f e e t AGL0.49561757E+02 HC [ gr ] below 3 ,000 f e e t AGL

3 User Guide 43

3.3 Other Tools

To carry out some of the analyses discussed in this reports, we have developed additional toolsthat operate on top of the main program or as a stand-alone utilities. One of these is a map toolthat 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 ofthe order of 1 m, are then transformed into useful maps for noise footprint calculations. Typicaloperations 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. Anexample 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 becalculated separately on each partition.

[m]

0

5000

10000

15000

5002500

0

300

600

900

N

M25

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

3 User Guide 44

3.3.1 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 donein the future, with the goal of reducing the computing time to a similar value to that of theturbofan 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 cannotbe given in this instance.

Restart ProcedureIf 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 theuser whether to restart or not. In the affirmative, the data are appended to the existing file andrestarting is done from the last grid point, identified automatically. In the other case, the existingfootprint output file is overwritten and computations start afresh.

The user can see where computations have been restarted, since each restart prints out a com-ment 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 specifiedflight 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. Theconfiguration file is as follows:

Listing 3.25: Typical configuration file aerotool.cfg.

# This i s the c on f i gu r a t i on f i l e f o r the AeroTool# Lines s t a r t i n g with hash−tag are comments and are ignored# Command l i n e s below cannot be swapped# omputer code w i l l not r e c ogn i s e swapped e n t r i e s”Airbus A320 200” ! a i r p l an e name70d3 ! a i r p l an e mass [ kg ]1000 .0 ! f l i g h t a l t i t u d e above mean sea l e v e l0 .30 ! t rue Mach number0 .0 ! change in a i r temperature over /below ISA at f l i g h t a l t i t u d e1 .0 ! a t t i t ud e angle , degree s1 . 0 ! bank angle , degree s1 ! Landing gear : iLG = 0 ( r e t r a c t ed ) ; other number ( deployed )0 ! s l a t / f l a p : iSF = 0 ( r e t r a c t ed ) ; other i n t e g e r ( deployed )

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 thebank 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 theairplane 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 airplaneat the specified flight conditions. This tools runs without user I/O. It reads configuration fileenginetool.cfg in the ./Data sub-folder and prints-out the output enginetool.out in the work-ing folder. The configuration file is as follows:

Listing 3.26: Typical configuration file enginetool.cfg.

# This i s the c on f i gu r a t i on f i l e f o r the AeroTool# Lines s t a r t i n g with hash−tag are comments and are ignored# Command l i n e s below cannot be swapped ; code w i l l not r e c ogn i s e swapped e n t r i e s”Airbus A320 200” ! a i r p l an e name1000 .0 ! f l i g h t a l t i t u d e above mean sea l e v e l0 .30 ! t rue Mach number80 .0 ! N1ggp−req , eng ine rpm , t y p i c a l l y 25 < N1ggp−req < 1030 .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 therequested engine state. Typically, this is a number 25% ¡ N%1 ¡ 104%, which can be associated toa throttle setting.

Typical run time of this tool is about 0.25 seconds. On output, it provides the net thrust FNof one engine of the airplane at the operational environment.

The EngineTool and the AeroTool can be used in combination to solve general flight mechanicsequations.

3.4 Error Messages

There are several types of errors. They should all be described as a screen message with the addresswhere 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 andsome information that may be helpful in fixing the error. There are over 420 recorded possibleinstances of errors. If you think that the error is a programming bug, please report the problemto the author.

Chapter 4

Guide to Propeller Code

The propeller module is provided as two independent codes: propnoise, used by FLIGHT on all tur-boprop aircraft, and propeller, which is a stand-alone user-input code with several performanceoptions, 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 integernumber. At that point the code loads the basic propeller data, constructs the geometry, calculatesall 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 inthe working directory. Once all this is done, the program is ready to go. The options available arepresented in Listing 4.1.

Listing 4.1: Propeller Analysis Options

Prope l l e r Ana lys i s /Design Options−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−Prope l l e r Geometry [ 0 ]

Performance at Design Point [ 1 ]Performance in Oblique F l i gh t [ 2 ]Performance Charts [ 3 ]P r ope l l e r Design [ 4 ]P r ope l l e r Trim [ 5 ]P r ope l l e r Noise [ 6 ]Performance o f Ducted Prop [ 7 ]S e n s i t i v i t y Ana lys i s [ 8 ]


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 outputfiles that can be visualised (see for example Figure 4.1). This option also performs a numberof aerodynamic and structural ancillary calculations. No performance calculations are carriedout.

46

4 Propeller Module 47

-101

z, m

-2

-1

0

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 correspondingto a non axial flight. The program then computes the aero-propulsive performance at thispoint and prints out various data, including loads distributions on the propeller disk. Thesub-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 Axial F l i gh t Options−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−Sing le−Point Ana lys i s [ 1 ]Yaw sweep [ 2 ]Pitch sweep [ 3 ]

Exit /Return [ any key ]

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


Input data must be sensible, otherwise the code will not converge. In general convergence isgood at high power settings, less so at low power settings. The results include the propulsiveefficiency, the thrust and power coefficients, the thrust, power and torque.

6. This option [6] calculates the propeller noise at the default operational conditions. Onesuch default listing is given below (Listing 4.3). Use the numbered options to change theoperational conditions.

Listing 4.3: Operational conditions for propeller noise (default)

Prope l l e r Noise Setup . Defau l t va lue s shown . Use opt ions to change−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Fl i gh t Mach number ( 0 . 32 ) [ 1 ]F l i gh t a l t i t u d e ( 1000 m) [ 2 ]Required Shaft Power ( 975 kW) [ 3 ]

Rece iver a l t i t u d e ( 10 m) [ 4 ]Distance to prop ( 300 m) [ 5 ]La t e ra l d i s t ance to prop ( 10 m) [ 6 ]

Temperature change /ISA (0 K) [ 7 ]Re l a t i v e Humidity (70 %) [ 8 ]

Execute [ 9 ]


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 effi-ciency 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.


Listing 4.4: Propeller design data

”Unknown” prop name ! p r o p e l l e r name”1 . 1 . 0 ” prop ve r s i on ! p r o p e l l e r model v e r s i on” c l o ckw i s e ” c l o ck ! s ense o f r o t a t i on ( f r on t view )

2 nsec t ! number o f r e f e r e n c e s e c t i o n s0 .32 r s e c t (1 ) ! r a d i a l p o s i t i o n o f inner s e c t i o n [m]1 .90 r s e c t (2 ) ! r a d i a l p o s i t i o n o f outer s e c t i o n [m]4 nb ! number o f b lades [ no un i t ]1 .910 d e s i gn r ad i u s ! des ign rad iu s [m]

1100 . design rpm ! des ign rpm ( take−o f f ) [ no un i t ]950 . rpm climb ! rpm ra t i ng at cl imb cond i t i on [ no un i t ]900 . rpm cru i se ! rpm ra t i ng at c r u i s e cond i t i on [ no un i t ]

5d3 d e s i g n a l t ! des ign f l i g h t a l t i t u d e [m]1 .35 d2 design TAS ! des ign true a i r speed [m/ s ]1700d3 des ign power ! des ign sha f t power [W]0 .30 d e s i g n c u t o f f ! hub c u t o f f [m]

” chord” 8 s t r i ng , ns input ! number o f r a d i a l p o s i t i o n s

0 .15 0 .31 y/R, chord ! spanwise p o s i t i o n & chord [m]0 .40 0 .31 y/R, chord ! spanwise p o s i t i o n & chord [m]0 .50 0 .32 y/R, chord ! spanwise p o s i t i o n & chord [m]0 .60 0 .32 y/R, chord ! spanwise p o s i t i o n & chord [m]0 .70 0 .32 y/R, chord ! spanwise p o s i t i o n & chord [m]0 .80 0 .32 y/R, chord ! spanwise p o s i t i o n & chord [m]0 .90 0 .28 y/R, chord ! spanwise p o s i t i o n & chord [m]1 .00 0 .26 y/R, chord ! spanwise p o s i t i o n & chord [m]

170 . prop mass ! p r o p e l l e r mass [ kg ]

0 .25 d0 eps xx prop ! ang le between prop ax i s & a i r p l an e ax i s ‘ ‘ x ’ ’

‘ ‘ sc1095 . polar ’ ’ s f i l ename (1) ! po la r f i l e , i nne r s e c t i o n‘ ‘ sc1094r8 . polar ’ ’ s f i l ename (2) ! po la r f i l e , outer s e c t i o n

‘ ‘ sc1095 . dat ’ ’ fo i lname (1) ! a i r f o i l s e c t i on , hub‘ ‘ sc1094r8 . dat ’ ’ f o i lname (2 ) ! a i r f o u l s e c t i on , t i p

Chapter 5

Case Studies

A limited number of results are shown to both demonstrate the capabilities of the program andits comparisons with reference data wind tunnel tests, flight recorder data, operating flight man-ual, etc.). We give an example (or more) in each of the main categories, except the geometricconfiguration, 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 ofthe ATR72-500. The reference (experimental) data have been inferred from a technical reportdescribing 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, thereforeno attempt was made to narrow the gap with data which are not properly assessed.

True angle of attack, degs

CL

CD x

10

-5 0 5 10 15 200

0.5

1

1.5

2

0

0.1

0.2

0.3

0.4

0.5

0

0.1

0.2

0.3

0.4

0.5

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

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

50

5 Case Studies 51

5.2 Airframe-Engine Integration: SAR Charts

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

True Mach number

SA

R,n

-mile

/lb

0.4 0.5 0.6 0.7 0.8 0.9

0.12

0.14

0.16

0.18

SA

R,n

-mile

/kg

0.4 0.5 0.6 0.7 0.8 0.9

0.12

0.14

0.16

0.18

0.28

0.32

0.36

0.4CalculatedFlight Manual

60

70

80

50 klb

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

5.3 Thermo-physics: Simulation of Fuel Tank Temperature

Thermo-physics problems include wing icing, tyre heating during ground roll and fuel temperaturein flight. Here, we provide an example of the latter. Figure 5.3, adapted from Ref.4 showsthe simulated fuel tank temperature of the Boeing B777-200 that suffered at crash at LondonHeathrow in January 20081. The fuel temperature model is fully synchronised with the flightmechanics. 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 temper-ature in flight with reasonable agreement with the FDR data.

1AAIB. Accident to Boeing B-777-236ER, G-YMMM at London Heathrow Airport on 17 January 2008, InterimReport EW/C2008/01/01, UK Dept. for Transport.

5 Case Studies 52

Flight time, min

Tem

pera

ture

,K

0 180 360 540200

220

240

260

LIQ fuel Temp (caVAP fuel Temp (caSAT*

Tank fuel volume*

Jet A1 freezing

Fuel Temperature*

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 coreflow having a temperature of 800 K, with the receiver at polar angle of 40 and 90 degrees, measuredfrom 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 movementsat 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 certainlyone of the most important.

Figure 5.7 shows an example of fuel derivative calculation at constant BRGW for the BoeingB777-300 with GE-92 turbofan engines. Differences in the the derivative (dX/dm)BRGW arereflected in the slope of the of the OEW + payload weight versus aircraft range. This sensitivityparameter is discussed in Ref.3.

Figure 5.8 shows the payload-range chart calculated for the Airbus A380-861 with GP7200 tur-bofan engines, and the comparison with the performance claimed by the manufacturer. Althoughthe ferry-range is well within the tolerance of the manufacturer’s data, there are differences in the

5 Case Studies 53

log10 f

SP

L, d

B

2 3 440

50

60

70

80

90

Calculated, θ = 40 degExp. data, θ = 40 degCalculated, θ = 90 degExp. data, θ = 90 deg

Figure 5.4: Validation of coaxial jet noise.

maximum-fuel range, due to some discrepancies in the fuel derivative illustrated in the previouscase (Figure 5.7). This is a problem that occurs often, but generally it is not wise to attemptto narrow this difference unless more information is provided on how the “reference” charts havebeen 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 completeairplane was modelled, including the calculation of the aerodynamic derivatives. A solution forthe 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 inputof 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 apitch angle of 5 degrees, and specified power is shown in Figure 5.10. This is a standard outputfor the propeller code.

5 Case Studies 54

[m]

[m]

-12000 -8000 -4000 0 4000

-2000

-1000

0

1000

2000 SEL[dB]95908580757065

wind

(a) EPNL

[m]

[m]

-12000 -8000 -4000 0 4000

-2000

-1000

0

1000

2000 SEL[dB]95908580757065

wind

(b) SEL

[m]

[m]

-12000 -8000 -4000 0 4000

-2000

-1000

0

1000

2000 LAmax[dBA]1009590858075706560

wind

(c) LAmax

[m]

[m]

-12000 -8000 -4000 0 4000

-2000

-1000

0

1000

2000 PNLTM[dBA]10510095908580757065

wind

(d) PNLTM

[m]

[m]

-12000 -8000 -4000 0 4000

-2000

-1000

0

1000

2000 LAeqT[dB]75706560555045

wind

(e) LAEQ

Figure 5.5: Noise footprint at landing for a Boeing B737-800 with CFM56 engines. Travel is fromleft to right.

5 Case Studies 55

[km]0

5

10

15[km]

-20

2

Flight V. 6.2.6

departing

arriving

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

Range, 10 3 n-miles

OE

W+

Pay

load

,ton

s

1 2 3 4150

175

200

225

Boeing’s dCalculated

BRGW = 235.8 tons

MZFW = 224.540 tons

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

5 Case Studies 56

Range, n-miles

Pay

load

, ton

s

2000 4000 6000 8000 100000

20

40

60

80

100

2000 4000 6000 8000 100000

20

40

60

80

100

AIRBUS Data

Max Pax Load

2000 4000 6000 8000 100000

20

40

60

80

100

MSP = 90,718 kg

MSP = 83,700 kgCalculated

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

Time, s

α [d

eg],

q [

deg

/s]

2 4 6 8 10 12-1.5

-1

-0.5

0

0.5

1attitudepitch rate

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

5 Case Studies 57

dCP

1.10E-039.00E-047.00E-045.00E-043.00E-04

Ψ = 0

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

Chapter 6

Selected Output Files & Data

The program FLIGHT can provide in excess of 100 output files; to the novice, it can be a dauntingtask to muddle through all this amount of data. Each operation invoked will provide at least oneoutput 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 A320-211 powered by CFM56 turbofan engines. Most of the parameters should be self-explanatory. Notethat the header contains information about the version of the softare, the database, the propellerversion, the software build level, the airplane model, the engine model, etc. The report ends witha 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) = 64.317 [ton]

Airfield altitude (A) = 50.00 [m]

Air temperature (T) = 0.00 +/- ISA

Wind speed = -2.00 [m/s]; -3.9 [kt]

Runway state = dry

Tyre-road slip ratio = 0.025

58

6 Output Data 59

Flap setting = 20.000 [deg]

Max lift coefficient = 2.421

Stall speed = 51.93 [m/s]; 100.95 [kt]

Roll friction coeff. = 0.025

Brake friction coeff. = 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 = 20 [deg]

Rotation Velocity (VR) = 79.42 [m/s]; 154.39 [kt]

Rotation distance (XR) = 886.38 [m]

Rotation Time (TR) = 25.55 [s]

Lift-off Velocity (VLO) = 87.32 [m/s]; 169.74 [kt]

(CAS) = 178.33 [kt]

Lift-off distance (XLO) = 1105.34 [m]

Lift-off Time (TLO) = 28.70 [s]

Velocity over screen (VTO) = 92.05 [m/s]; 178.94 [kt]

Lift/Drag over screen = 16.343

Lift-off CL = 1.425

Mach no. over screen = 0.271

Distance to screen (XTO) = 1319.32 [m]

Time over screen (TTO) = 31.50 [s]

Climb angle over screen = 6.51 [deg]

Total take-off distance = 1319.32 [m]

Total take-off time = 31.50 [s]

Fuel burn = 178.02 [kg]

Minimum control speed, VMCG = 61.91 [m/s] 120.34 [kt]

Stall speed , VS = 51.93 [m/s] 100.95 [kt]

Max (main) tyre temperature = 292.1 [K] rise = 1.2 [K]

Max (nose) tyre temperature = 399.6 [K] rise = 99.6 [K]

Main tyre temp. over screen = 291.0 [K]

Nose tyre temp. over screen = 300.0 [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 60

6.1.1 AEO Climb of an Airbus-A320 Airplane Model

The following block shows a report for the climb to an initial cruise altitude. The terminal pointof the climb (M, z) is determined by local optimisation. This optimisation leads to the best flightlevel and the best Mach number, which is then used as a target for the climb shown below.

--------------------------------------------------------


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





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 [over screen]

0 0.401 988.2 3.64 4.20 828. 121.5 0.557 [800-ft target]

1 250.00 289.21 0.451 3118.0 3.18 15.97 3143. 141.8 0.743 [const CAS]

2 250.00 289.21 0.451 3118.0 0.00 0.00 0. 0.0 0.347 [accelerate]

3 248.57 429.91 0.748 11012.3 19.92 6.60 1300. 479.8 0.401 [const CAS]

4 237.79 429.52 0.748 11582.4 2.00 4.83 950. 44.6 0.371 [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


Selected points in the climb are shown in the report above. For each flight segment, the reportshows the distance flown, the flight time, the average climb rate (vc), the fuel burn (mf), the aver-age 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 fromthe mission planning point of view are the time, fuel and distance to initial cruise altitude (ICA).

6 Output Data 61

6.1.2 Cruise Performance of an Airbus A320 Airplane Model

The following output shows an example of cruise report. In this specific case, the aircraft flies ata constant flight level for the entire duration of the cruise (about 560 n-miles). Both Initial CruiseWeight (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 adjusteddown, since the optimal level is unrealistic (for example, FL-380). Note that in this case there isno step climb.

--------------------------------------------------------


Revision : b

Database : 20.2.0

Prop_Noise : 3.8.1

Build : 4846/50.7%

Licensed to : Owner

--------------------------------------------------------

JOB IDENTITY

--------------------------------------------------------






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 62

6.1.3 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 fromthe end of the cruise down to 1,500 feet above airfield elevation. The critical segments are indicatedline by line.

--------------------------------------------------------


Revision : b

Database : 20.2.0

Prop_Noise : 3.8.1

Build : 4846/50.7%

Licensed to : Owner

--------------------------------------------------------

JOB IDENTITY

--------------------------------------------------------






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 63

6.1.4 Mission Report of an A320 Model

The case below is a summary of mission calculations (Option 1 in Listing 3.4). There are varioussub-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.) FinalMass/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 = 5401.64 [ton*nm/hr]

Theoretical range = 809.94 [nm]

Effective range = 1060.85 [nm]

Equivalent all-out range = 1106.60 [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 = 15 [kg]

Average pax weight = 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


Nomenclature 65

6.2 Nomenclature & Conventions

Flight Mechanics

AEO = All Engines OperatingAGL = Above Ground LevelAUW = All-up weightAPU = Auxiliary Power SystemBRGW = Brake-release Gross WeightCAS = Calibrated Air SpeedCG = Center of GravityEGT = Exhaust Gas TemperatureFAR = Federal Aviation RegulationsFCW = Final Cruise WeightFDR = Flight Data RecorderFL = Flight LevelFLS = Flight Level SeparationGLW = Gross Landing WeightGRW = Gross Ramp WeightGTOW = Gross Take-Off WeightHPC = High Pressure CompressorHPT = High Pressure TurbineICA = Initial Cruise AltitudeICW = Initial Cruise WeightISA = International Standard AtmosphereIFLAP = Inboard FlapISLAT = Inboard SlatLPC = Low Pressure CompressorLPT = Low Pressure TurbineLTO = Landing and Take-offOAT = Outside Air TemperatureOEI = One Engine InoperativeOFLAP = Outboard FlapOSLAT = Outboard SlatMLR = Long-Range Mach NumberMMR = Maximum-Range Mach NumberMMO = Maximum Operating Mach NumberMSP = Maximum Structural PayloadMZFW = Maximum (design) Zero-Fuel WeightSAR = Specific Air RangeSAT = Static Air TemperatureTAS = True Air SpeedTAT = Total Air TemperatureTOW = Take-off WeightTSFC = Thrust-Specific Fuel ConsumptionVMCG = Minimum Control Speed on the GroundZFW = Zero-fuel weight

Nomenclature 66

Noise Metrics

EPN = Effective Perceived Noise Level (also EPNL)LAmax = A-weighted Maximum Sound Pressure LevelLAEQ = Equivalent Sound Level (also LAeqT)PNL = Perceived Noise LevelPNLTM = Perceived Noise Level, Maximum ValueSEL = Sound Exposure LevelSPL = Sound Pressure LevelTAUD = Time-Audible

Noise Breakdown

SRCt[s] = source (flight) time, sRECt[s] = receiver (flight) time, sx[km] = flight distance, x-direction, kmy[km] = flight distance, yx-direction, kms[km] = ground track, kmh[km] = geometrical altitude of the airplane, kmh[kft] = geometrical altitude of the airplane, 1,000 feetr[km] = distance CG to receiver on the ground, kmtheta = polar emission angle, degsKTAS = true air speed, ktLGear = flag to denote landing gear deployed (1) or retracted (0)Flap = high-lift position: 1, 2, · · ·Wing = wing noiseHSTAB = horizontal stabiliser noiseVSTAB = vertical stabiliser noiseSLAT = slat noiseFLAP = flap noiseNLG = nose landing gear noiseMLG = main landing gear noiseFAN = fan noise (corrected for duct absorption & duct acoustics)xLPC = low-pressure compressor noiseHPC = high-pressure compressor noiseCOMB = combustor SPLHPT = high-pressure turbine noiseLPT = low-pressure turbine noiseJET = coaxial jet SPLProp = propeller noiseAPUC = APU compressor noiseAPUJ = APU jet noiseOASPLa = overall sound pressure level, airframeOASPLe = overall sound pressure level, engineOASPL = overall sound pressure levelPNL = perceived noise level, dBALoud = loudness, dBA

Nomenclature 67

Noise Trajectories

WC[kg/s] = core mass flow rate, kg/sW1[kg/s] = mass flow rate, kg/sFN[kN] = net thrust, kNN1% = gas generator turbine speed, in percentTT4[K] = combustor entrance temperature, KTT5[K] = high-pressure turbine temperature, KEGT[K] = exhaust gas temperature, K

Payload-Range Charts

X[nm] = range, n-milesXc[nm] = en-route climb distance, n-milesGRW = gross ramp weight, tonBRGW = brake-release gross weight, tonGTOW = gross take-off weight, tonFCW = final cruise weight, tonGLW = gross landing weight, tonWPay = payload weight, tonWfuel = fuel weight, tonWfclimb = climb fuel, tonWfcruise = cruise fuel, tonWfdes = descent fuel, tonWfburn = fuel burned, tonSAR[nm/kg] = average specific air range, n-miles/kgCO2 = CO2 emissions, tonICA = initial cruise altitude (flight level)FCA = final cruise altitude (flight level)MLR = long-range Mach numbert[min] = flight time, minutesblock[min] = block time, minutesMobs = Mach number over screen (takeoff)Gobs = Initial climb gradient (takeoff)Tobs = Time over screen (take-off)

Nomenclature 68

Gas Turbine Engine Symbols

FN = Net thrustMach9 = Nozzle Mach number (core side)N%1 = Low pressure rotor rpm, %N%2 = High pressure rotor rpm, %PS9 = Total static nozzle pressurePT3 = HP Compressor pressure, exitPT14 = Bypass flow total pressure, exitPT2.5 = LP compressor exit pressureTSFC = Specific fuel consumptionTS9 = Total static nozzle temperatureTT2.1 = Exit fan temperature (core side)TT2.2 = Exit fan temperature (bypass side)TT2.5 = LP compressor exit temperatureTT3 = Combustor inlet temperatureTT4 = Exit combustor temperatureTT5 = Power turbine temperatureTT14 = Bypass flow temperature, exitW1 = Mass flow rateWC2.5 = Core mass flow rateWf 6 = Fuel flow rateW14 = By-pass mass flow rate

Bibliography

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[2] Filippone A. Flight Performance of Fixed and Rotary Wing Aircraft. Elsevier, 2006.

[3] Filippone A. Comprehensive analysis of transport aircraft flight performance. Prog. AerospaceSciences, 43(3), April 2007.

[4] Filippone A. Theoretical framework for the simulation of transport aircraft flight. J. Aircraft,47(5):1679–1696, 2010.

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[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 StaticStability, 252, pages 2651–2660. John Wiley & Sons Ltd, 2010.

[9] Filippone A. Encyclopaedia of Aerospace Engineering, volume 5, chapter Lateral Static Sta-bility, 253, pages 2661–2668. John Wiley & Sons Ltd, 2010.

[10] Filippone A, Bertsch L, and Pott-Pollenske M. Validation strategies for comprehensive aircraftnoise 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.

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[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.

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Nomenclature 70

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Appendix A

List of User-Defined Parameters

Listing A.1: User-Defined Parameters, Part 1

Name Value Desc r ip t i on−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

!− User−Parameters : ENGINES −−−−−−−−−−−−−−−−−−−user RSS comp = 50d0 ! r e l a t i v e rotor−s t a t o r d i s tance , any CPR stageuser RSS fan = 250d0 ! r e l a t i v e fan−vanes d i s t anceu s e r l i n e r t h i c k = 0.0667 ! a c ou s t i c l i n e r depth , f r a c t i on , fan diameteruser Mtipd CPR = 1.10 d0 ! max CPR ro t a t i n g t i p Mach numberu s e r c o r e f a n d i am ra t i o = 0.475 ! v a l i d with approximation f o r with BPR = 5 to 8user PRduct = 0.0290 ! l o s s in p r e s su r e in bypass ductuser SR CPR blade = 10 ! nb l ad e s s t a t o r − nb lade s ro to r , any CPR stageuser b lade 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 lades , s i n g l e rowuser TRB blades 1HP = 85 ! number o f blades , 1 s t s tage HPTus e r e t a cp r = 0.98 d0 ! s i n g l e−s tage compressor e f f i c i e n c yus e r cyc l e wash = 1000 ! number o f eng ine c y c l e s be f o r e washingu s e r k i n l = 0 .25 d0 ! e s t imat ion o f eng ine i n s t a l l a t i o n l o s s e s , %u s e r t s f c p l o s s = 0 .1 d0 ! permanent e f f i c i e n c y l o s s a f t e r eng ine wash , %u s e r p l o s s = 2 .55d−2! permanent e f f i c i e n c y l o s s a f t e r washuser TRB heat f low = 4d−2 ! heat f low ra t e out o f core f low ( f r a c t i o n )u s e r powe r r a t i o = 2 .5 d0 ! maximum gearbox power l o s s , % max poweru s e r eng i n e t t ime = 3d0 ! 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 & CONTROL SURFACES −−−u s e r o u t e r t h i c k n e s s = 0 .90 ! wing th i c kne s s at t ip , r e f e r e n c eu s e r i n n e r t h i c k n e s s = 1 .14 ! wing th i c kne s s at root , r e f e r e n c eu s e r k f l a p = 1.70 ! incrementa l c o e f f i c i e n t , f l a p area , i f unknownu s e r k s l a t = 0 .90 ! incrementa l c o e f f i c i e n t , s l a t area , i f unknownu s e r s l a t p e r im = 2.50 ! r a t i o per imeter / chordus e r max rudde r de f l e c t = 25d0 ! max . rudder d e f l e c t i o n , degree su s e r max a i l e r o n d e f l e c t = 25d0 ! max . a i l e r o n d e f l e c t i o n , degree su s e r max s p o i l e r d e f l e c t = 60d0 ! max . s p o i l e r d e f l e c t i o n , degree su s e r max e l e v a t o r d e f l e c t = 20d0 ! max . e l e v a t o r d e f l e c t i o n , degree suse r max HT de f l e c t p lus = 13 .5 ! max . h−t a i l d e f l e c t i o n , degree suser max HT def lect min = −4d0 ! min . h−t a i l d e f l e c t i o n degree su s e r max r o l l r a t e = 15d0 ! max . r o l l rate , degree s / su s e r th e t a rudde r = 15d0 ! max . rudder d e f l e c t i o n , degree su s e r d e l t a a i l e r o n = 20d0 ! max . a i l e r o n d e f l e c t i o n , degree su s e r d e l t a s p o i l = 70d0 ! max . s p o i l e r d e f l e c t i o n , degree su s e r va rph i deg = 5d0 ! l im i t bank ang le f o r VMCA, degree s

71

User-Defined Parameters 72



!− User−Parameters : AERODYNAMICS −−−−−−−−−−−−−−user kkorn = 0.1395 ! Korn f a c t o r to es t imate t r an son i c drag r i s eu s e r t l a g f l a p = 2d0 ! time de lay between f l a p d e f l e c t & aero loads [ s ]

!− User−Parameters : WING TANKS −−−−−−−−−−−−−−−−u s e r t ank th i c kn e s s = 0 .35d−2! average thank s h e l l t h i c kne s s [m]u s e r x l e w ing tank = 0.15 d0 ! forward po s i t i o n o f wing tank (LE)use r x t e w ing tank = 0.32 d0 ! a f t p o s i t i o n o f wing tank (TE)user span wing tank = 0.71 d0 ! wing tank span , f r a c t i o n o f wing semi−span [m]

!− User−Parameters : TYRE QUANTITIES −−−−−−−−−−−u s e r t y r e g a s = ” a i r ” ! ty re i n f l a t i o n gasu s e r max ty r e d e f l e c t = 32d0 ! max . ty re d e f l e c t i o n , %u s e r h y s t e r e s i s = 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 −−−−−−−−−−−u s e r s h e l l t h i c k = 0.080 ! f u s e l a g e s h e l l t h i c kne s s [m] , averageuser p i tch down = −1d0 ! nose−down a t t i t ud e on the ground , degsuser xCGMAC min = 18d0 ! maximum forward po s i t i o n o f CG wrt to MACuser xCGMAC max = 45d0 ! maximum a f t p o s i t i o n o f CG wrt to MAC

!− User−Parameters : FLIGHT OPERATIONS −−−−−−−−−use r tu rb = 0 .2 d0 ! f r e e stream turbu lence f o r f l i g h t ana ly s i s , %user runway max length = 3d3 ! maximum runway length [m]u s e r u t ax i = 5d0 ! average ground/ tax i speed , m/ su s e r x ro l l max = 2 .0 d0 ! average r o l l /ground di s tance , kmu s e r t im e l a g s p o i l e r = 0.750 ! take−o f f / land abort : s p o i l e r re sponse time [ s ]u s e r t ime l ag b rake = 0 .5 d0 ! take−o f f abort : brakes re sponse time [ s ]user Vgstab = 12d0 ! min . ground speed f o r s p o i l e r s deploymentuse r RevThrust f rac = 0.15 d0 ! r e v e r s e th rus t opt ions , f r a c t i o nuser URevThrust = 100d0 ! min speed f o r r e v e r s e thrust , [km/h ]u s e r l im r o t t ime = 2 .5 d0 ! max . r o t a t i on time at f l a r e / t a k e o f f [ s ]u se r vbrake = 15d0 ! max . braking speed at landing , km/huser hLGDeploy = 450d0 ! he ight o f LG deployment , above a i r f i e l d [m]user hLGRetract = 76d0 ! he ight o f LG re t r a c t i on , above a i r f i e l d [m]use r tde l ay LGre t rac t SL = 2 .5 d0 ! time delay between LG r e t r a c . & f l a p r e t r a c t .u s e r tde l ay F2 = 5d0 ! time de lay between LG deploy & FLAP2 switch [ s ]user wbag = 15d0 ! baggage a l lowance [ kg ]user wpax = 75d0 ! avg weight o f passenger [ kg ]user wcrew = 95d0 ! avg weight o f crew + baggage [ kg ]u s e r unu s ab l e f u e l = 0.006 ! unusable fu e l , f r a c t i o nu s e r n c r e w f i r s t c l a s s = 11 ! pas senge r s per f l i g h t attendant , bu s in e s s c l a s su s e r n c r ew t ou r i s t = 31 ! pas senge r s per f l i g h t attendant , economy c l a s su s e r s ea t mas s1 = 21d0 ! s ea t mass , economy [ kg ]u s e r s ea t mas s2 = 42d0 ! s ea t mass bus in e s s [ kg ]u s e r s e a t o t h e r = 15d0 ! seat−r e l a t e d mass [ kg ]u s e r i d l e t im e = 1560.0 ! i d l e time = 26 minutes (ICAO) , converted to [ s ]user kpaxo = 3d0 ! min . weight o f s e r v i c e s / passenger [ 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 / passenger [ kg/pax ]user min turboprop range = 150d0 ! min . range o f turboprop a i rp lane , [km]use r min turbo fan range = 250d0 ! min . range o f turbofan a i rp lane , [km]user Mach DIVE = 1.070 ! DIVE Mach number de f ined as : MMO*user Mach DIVEuser NLF UTurn = 1.150 ! normal load f a c t o r used f o r U−turn

User-Defined Parameters 73



!− User−Parameters : FLIGHT MANOUVRES −−−−−−−−−−use r hc l imb turn = 400 .0 ! a l t i t u d e at which a i r c r a f t performs turn [m]u s e r d r i f t = 30d0 ! max . a l lowed sideways d r i f t , OEI take−o f f [ f t ]u se r ty re yaw = 5d0 ! f i x ed tyre yaw during VMCG [ degs ]u s e r dp s h e l l = 59 .3 d3 ! max . p r e s su r e d i f f e r e n c e between cabin & ext

!−−−− User−Parameters : NOISE −−−−−−−−−−−−−−−−−−−−−us e r L tu rb s c a l e = 1 .1 d1 ! turb . l ength sca l e , no i s e propagat ion [m]u s e r f l o o r dB = 1d−2 ! min . SPL [dB ] ; avo ids over f low , NaN, in l og opsuse r rmax no i s e = 9 .67 d3 ! max . d i s t ance to c a l c u l a t e no i s e [m]use r romax no i s e = 3 .15 d3 ! max . d i s t ance on ground to c a l c u l a t e no i s e [m]u s e r max no i s e a l t = 1 .5 d3 ! max a l t i t u d e AGL f o r no i s e c a l c u l a t i o n s [m]user Vmin Anoise = 3d0 ! min . a i r speed f o r a i r f rame no i s e [m/ s ]u se r min sep t ime = 55d0 ! min . f l i g h t s epa ra t i on time [ s ]user max sep t ime = 180d0 ! max . f l i g h t s epa ra t i on time [ s ]u s e r bu i l d h e i g h t = 4d0 ! average b a r r i e r he ight o f bu i ld ing s , [m]u s e r SPL sh i e l d ing = 55d0 ! min . SPL to t r i g g e r wing/ eng ine /prop s h i e l d i n gu s e r w ind no i s e = 2.060 ! min . a i r f i e l d wind speed in no i s e propag . [m/ s ]use r max prop d i s tance = 1 .5 d3 ! max d i s t ance prop−r e c e i v e r f o r p r o p e l l e r no i s e

!− User−Parameters : OTHER STUFF −−−−−−−−−−−−−−−use r pop dens i t y = 2300 ! average o f Stockport / Sa l f o rd [ people /kmˆ2 ]

Index

AAIB, 52Acoustic liners, 36AGL, 39Airbus A320-211, 22Airbus A380, 44, 53Aircraft design, 6APU, 6, 11, 23ASCII files, 14Atmosphere, 8, 11, 20–22

Background noise, 36Batch jobs, 42Boeing B737, 53Boeing B777, 52

Contrails, 5, 11, 22Cost functions, 43CPU, 34, 42

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

Error messages, 46

F568 propeller, 49FDR, Flight Data Recorder, 52Flight dynamics, 28Fortran, 6, 44Fuel tanks, 9

Go around, 28Gust response, 28

Linux, 12London Heathrow, LHR, 44

Matlab, 6, 14, 44Mean aerodynamic chord, 15MS Windows, 12

Noise, 32

directivity, 35maps, 44

Phogoid, 28Propeller, 27, 42, 47

Hamilton F568, 54

Restart, 45

Short-period of motion, 28Specific air range (SAR), 52Specific excess power (SEP), 28

Thermo-physics, 52Tools

aerodynamics, 45noise maps, 44propulsion, 46

Type certificate, 6

VMCA, min control speed, 28Volumes, 28

WAT charts, 28, 29Wing box, 15

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Flight Performance Software FLIGHT - University of 2.4 Cruise drag of the Airbus A320-211 ... * The...

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