In-Flight Simulators and Fly-by-Wire/Light Demonstrators: A Historical Account of International Aeronautical Research

359 Pages·2017·37.03 MB·English

by  Peter G. Hamel (eds.)

Peter G. Hamel Editor
Translated by Ravindra V. Jategaonkar
In-Flight Simulators
and Fly-by-Wire/Light
Demonstrators
A Historical Account of
International Aeronautical Research
In-Flight Simulators and Fly-by-Wire/Light
Demonstrators
Peter G. Hamel
Editor
In-Flight Simulators
and Fly-by-Wire/Light
Demonstrators
A Historical Account of International
Aeronautical Research
Translated by
Ravindra V. Jategaonkar
123
Editor
PeterG.Hamel
Director (Retired)
DLRGerman Aerospace Center
Institute of Flight Systems
Braunschweig
Germany
e-mail: [email protected]
[email protected]
Translated by
Ravindra V.Jategaonkar
SeniorScientist (Retired)
DLRGerman Aerospace Center
Institute of Flight Systems
Braunschweig
Germany
e-mail:[email protected]
Thisbook canbeindexed,referenced, andcitedas follows:
In-Flight Simulators and Fly-by-Wire/Light Demonstrators: A Historical Account of International
Aeronautical Research, Edited by Peter G. Hamel, Translated by Ravindra V. Jategaonkar, and
published bySpringer, March2017.
Revised, extendedandtranslated from the originalbookin German:
“Fliegende Simulatoren und Technologieträger: Braunschweiger Luftfahrtforschung im internationalen
Umfeld“, edited by Peter G. Hamel and published by Appelhaus Verlag, Braunschweig, 2014, ISBN
978-3-944939-06-3.
ISBN978-3-319-53996-6 ISBN978-3-319-53997-3 (eBook)
DOI 10.1007/978-3-319-53997-3
LibraryofCongressControlNumber:2017933443
©SpringerInternationalPublishingAG2017
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Be more attentive to new ideas from the research world
George S. Schairer,
Former Vice President Research, Boeing (1989)
Foreword to the English Edition
For the first 40 years of aviation, most of the failures of the earliest attempts at powered,
fixed-wing flight were associated with inadequate understanding of dynamic stability and
control. Although Lanchester, Bryan, and Williams had already developed the theory of
aircraft dynamics by the early 1900s, their work still had found negligible use for design
purposes by aslate asthe mid 1940s. However, WWII brought demands formaneuverability
so that aircraft dynamic stability and control has been a focus of attention ever since.
Itwasthroughtheresearchandthetechnologydemonstratorsthatareexcellentlyreviewed,
chronicled,anddocumentedinthisbookthattheaviationindustrygainedanunderstandingof
aircraft stability and control. With that knowledge, aircraft designers have been freed
forevermorefromtheconstraintsoftheclassicalconceptionofstabilityandcontrolassociated
with fixed stabilizing fins and manually movable surfaces for control. Fly-by-Wire artificial
stability systems give the designer the flexibility to design an aircraft solely from the per-
spective of performance and ignore the classical stability requirements. The genesis of the
development of artificial stability was in the pioneering work that was done primarily in the
United States and in Germany (often in collaboration).
IntheUS,theearlybasicstudieswereconductedinthe40sand50sbyNASAandbythe
Flight Research Department of the Cornell Aeronautical Laboratory (CAL, now called Cal-
span) with totally different objectives.Thescientists atNASAwereseekingways toimprove
theflyingqualitiesofaparticularexistingaircraftwithacontrolproblem.Meanwhile,CAL’s
objective was to develop methods for measuring and describing the dynamic stability and
control characteristics of any aircraft in flight. Both paths led to the invention of variable
stability aircraft that could be used in the early stages of design of automatic control for
stabilityaugmentation.ThisbookdescribesthemultipleprojectsinUSfrom1947untiltoday
that produced a progression of theoretical and experimental advances in aircraft dynamic
stability and control.
InGermany,significantcontributionstounderstandingdynamicstabilityandcontrolbegan
even earlier than did the work in the US, but there too, as with NASA, the initial work was
largely concerned with correcting an existing control problem. Since WWII, important con-
tributions have come mostly from the Institute of Flight Mechanics of DFVLR (since 1999
Institute of Flight Systems of the German Aerospace Center—DLR) in Braunschweig. That
Institute,undertheleadershipofitsDirector,Dr.PeterG.Hamel,hasestablishedaworldwide
reputation for its expertise in all the fields related to flying-qualities investigations and, in
particular, the development and highly innovative use of their in-flight simulators of both
fixed-wing and rotary-wing aircraft, and their novel applications of Fly-by-Wire and
Fly-by-Light.Althoughautopilotfunctionswithlimitedstabilizationwerealreadyavailableon
aircraft with mechanical flight control systems, stability augmentation and variable stability
aircraft would not have been possible without Fly-by-Wire. Peter and his Institute are also to
be credited with their pioneering work in the adaptation of the concepts of system identifi-
cation to flight vehicles.
Aircraft system identification is a way to build the accurate mathematical model of an
aircraftthatisessentialtodesigningaugmentedstabilityandautomaticcontrolforthataircraft.
vii
viii ForewordtotheEnglishEdition
An ever-increasing number of modern civilian and military aircraft is inherently aerody-
namically unstable. However, thestability augmentationand automated controlthat arebasic
to all current aircraft designs ensures the comfort and safety of your flight.
Peter and his collaborators at the DLR Institute of Flight Systems achieved important
advancements in the multiple technologies of stability augmentation and in-flight simulation
decades before they were thought of anywhere else. These achievements have been particu-
larlynotedandpraisedbytwowell-knownexpertsinthefield,MalAbzugandGeneLarrabee,
in their 2002 book titled, “Airplane Stability and Control: A history of the technologies that
made aviation possible”.
Peterandtheco-authorsofthisbookhavemadeanoteworthycontributiontothehistoryof
aviation.Thebookistheconsequenceofanenormousefforttocoverthecompletespectrumof
internationalcontributionsintheevolutionofartificialstability,variablestabilityaircraft,and
in-flightsimulation.ItalsoaddressesthedevelopmentofthetechnologiesofFly-by-Wireand
Fly-by-Light that made these developments possible. While this book presents an exhaustive
account of variable stability and Fly-by-Wire research and demonstrations worldwide, it
emphasizestheworkinGermanyand,inparticular,atDLR’sInstituteofFlightSystems.The
prominenceofdescriptionsofrelatedactivitiesinGermanyisunderstandableandappropriate
considering that much of the pioneering work was done there and that this is the first time it
has been so well documented. The extensive efforts in Germany that go back over 100 years
and,inparticular,theachievementsattheInstituteofFlightMechanicscontributedprofoundly
to the development of stability and control augmentation and the use of in-flight simulation.
I can personally attest to the scope and value of contributions to the current state of under-
standing aircraft dynamic stability and control made by Peter and his Institute. I have known
Peter G. Hamel for over 40 years and I have had the pleasure of collaborating with him in
several projects related to the topics of this book. Through my personal knowledge, I can
vouch, without hesitation that he is eminently well qualified to chronicle and evaluate the
worldwide developments of these capabilities that have become essential to aviation.
This book will be of interest not only to novices, but also to practicing scientists and
engineersandtothoseinterestedinaviationhistory.Thiscomprehensivehistoricalaccountis
devoid of mathematical equations and deep theoretical discussions, but it is full of tales of
innovativeexperimentsandcreativethinking,amusinganecdotes,andfascinatingphotosthatI
have no doubt the readers will enjoy. So, my advice to the hesitant reader is, if you are
interestedingainingreliableknowledgeabouttheorigins,theinnovators,andtheevolutionof
stability augmentation, variable stability aircraft, and in-flight simulators as well as of
Fly-by-Wire/Light this is the book for you.
Mountain View, CA, USA Irving C. Statler
September 2016 Principal Engineer, Flight Research Department
Cornell Aeronautical Laboratory, 1946–1970
Director, U.S. Army Aviation Aeromechanics Laboratory, 1970–1985
Director, NATO Advisory Group for Aerospace R&D, 1985–1988
Research Scientist, Human Factors Research Division
NASA Ames Research Center, 1988–2008
Foreword to the German Edition
A beautiful definition of performance is: “A impersonates B, while C observes”. Applied to
the in-flight simulation, a highly sophisticated modified aircraft “impersonates” in real flight
anothervehicleinthesenseofa“flyingactor”,while scientistsandengineers“observe”,that
is, analyze the outcome offlight to make decisions.
One shouldbeabit careful whileusing theterm “supremediscipline”,nomatter inwhich
area,becausetherebyyouimplicitlydegradeallotherdisciplinesinthesamefield,orinother
wordsassignthemalowerimportance.Inthepresentcase,however,itseemsjustifiedtospeak
of in-flight simulation possibly as a “supreme discipline” in aircraft construction, as it
encompasses all other disciplines such as aerodynamics, flight mechanics, construction,
structures,aircraftsystems,andaeroelasticity.Inordertogetanin-flightsimulatoroperational
in the air, best experts in all these fields have to work together, as one encounters the
boundaries of physical sciences and engineering techniques, which have to be fathomed and
extendedinthismostchallengingtask.Thiswastrueinthepastwithfewertoolsavailableto
developaircraftsuchasthetechnologydemonstratorVFW614ATTAS,justliketodaywhen
the demands on the prediction accuracy have increased with the availability of better
numerical and experimental tools.
ItgoestothecreditofPeterG.Hamelasaninitiatorandeditorofthisbook,supportedby
manywhowereinvolvedthenaswellaseventoday,tohavelookedbackandreappraisedthe
technicalhistoryofin-flightsimulation.Forhiscontributionsinthisfield,hewashonoredwith
themostprestigiousaward“Ludwig-Prandtl-Ring”oftheGermanSocietyforAeronauticsand
Astronautics. Prandtlwas theone who has provideda scientific basis to flight science, which
was still in the infant stages during the early twentieth century, through his work on the
boundary layer theory and the construction of wind tunnels. Almost a century after Prandtl’s
fundamental work, the author looks back at the history of in-flight simulation and illustrates
thereby the rapid development offlight physics.
ThishasalongtraditioninGermany.Inabroadsense,theworkofthefirstflightscientist
OttoLilienthalmaybeinterpretedinafigurativesenseascontributionstoin-flightsimulation.
Hewantedtoreplicatetheflightofbirdswithhisgliders.LaterthetheoreticalworkbyLudwig
Prandtl appeared, the aircraft profile and the flying wing by Hugo Junkers, the jet engine by
HansJoachimPabstvonOhain,andthesweptwingbyAdolfBusemann,justtonameafew.
Thisbookshowsimpressivelyhowtheeffortsofscientistsandengineersinthiscountryhave
contributed not only with technical achievements to the success of aeronautics, but also
established over a long period a highly successful unified community of research, education,
development, production and operations. Only such a close cooperation in a fertile network
guarantees a technically and socially valuable future in the days to come.
Aircrafthavechangedonlyalittleinrecentyears.However,thereisnowanurgentneedfor
fundamentally new aircraft to meet the growing demands for better cost effectiveness, envi-
ronmental sustainability, and passenger comfort. These new devices need different properties
thantheaircraftflyingtoday,andthesepropertiesmustbesimulatedinadvance,especiallyin
flight.Hence,theneedforsimulationsandin-flightsimulatorsishigherthanever,andassuch
this book is not only a historical reappraisal, but also represents a mandate for the future.
ix
x ForewordtotheGermanEdition
Thebookyouholdinyourhandsshowsinanexcellentmannerthetechnicalfacetsandthe
greateffortswhichareneededtosuccessfully“act”asaproblemsolverinaeronautics.Iwould
like to take this opportunity to sincerely thank the editor, Peter G. Hamel, not only for his
technicalexpertise,butalsoforhistenacityonthelongroadfromanideatorealizingthebook
initsimpressivefinalform.Tothereaders,Iwishmuchenjoymentinreadingthebook,many
insightsintotherichpast,ownperceptionsofthecurrentglobalstateoftheart,andinspiration
derived thereby for the future.
Cologne, Germany Rolf Henke
August 2016 Member of the Executive Board
German Aerospace Center (DLR)
President, German Society for Aeronautics and Astronautics (DGLR)
Foreword
In-flightsimulationistheultimateapproachinappliedflightsciencestoassessmentandevaluation
of aircraft and other aeronautical systems, as it represents the most intense fusion of flight
mechanics,flightcontrol,flightsystemstechnology,andflighttesting.Itisaversatiletoolforflight
researchandaircraftindustryalike.Startingwithstudiesoffutureconfigurationsuptothesimu-
lation of atmospheric phenomena including system influences, dependencies, and even failure
casescanbeaddressedwithin-flightsimulation,reachinghightechnologyreadinesslevels.
But is this approach still the best way to tackle the current and future questions in aircraft
flightresearchanddevelopment?Fromtheviewpointofaresearchinstitutionwithstronglinks
toaircraftindustryandgovernmentalpartners,wecanstatetodaythatin-flightsimulationstill
hasandmostprobablywilleverhaveanimportantroletoplayinaeronautics.Thereasonsfor
this are many and I would like to mention just three of them.
Firstly,newconfigurationsareabouttoenterthescenarioofmodernciviltransportaircraft
with possibly radical new features with no proven databases to rely on. Early in-flight sim-
ulations of potentially unstable configurations and, even more important, of the flight control
systems will be an efficient, fast, and reliable way to establish the required confidence of
engineers and management alike.
Secondly, the segment of unmanned flying vehicles is the fastest growing area in modern
aeronautics. Autonomously operating vehicles will enter the world’s airspace in the next
decades.Mannedandunmannedin-flightsimulationwillbeoneofthemostpowerfultoolsto
prove the maturity of new designs and, not to forget, new legal approaches to certification.
Thirdly, international aeronautics industry starts to detach from national institutions and
educationalsystems,leavingnationalauthoritieswiththetaskofmaintainingbasiccapabilities
inaeronauticaldesignanddevelopment.Asthein-flightsimulationplaceshighestdemandson
the key competencies of aircraft modeling, control, and integration, it is best suited to ensure
maintaining the expertise in these areas. This is all the more true in the future with new
systems having ever-increasing complexity and safety standards. The implementation of
in-flight simulation will help us to understand that technical capabilities will not be sufficient
tomakeaflightvehicledesignoptimalbuttheknowledgeonhowtodesignanddevelopwill
beasimportantasthetechnicalskillsandincludesadeepunderstandingofthehumans,acting
within the engineering, design, and decision processes.
Therearemanygoodreasonstopursueinthefuturethisjewelofmodernflightsciences.It
is apparent from this book that a symbiosis of scientific excellence at universities, research
institutions, industry capabilities, and political focus is mandatory in this pursuit. It is highly
appreciatedthattheauthorsofthisbookpresentthehighlights,achievements,andworldwide
historicalevolutionofthisaspectofflightengineeringsciences.Thankstotheauthorsforthis
brilliant and one of the most vivid compilations of aeronautic achievements that has been
given to international scientific communities!
Braunschweig, Germany Stefan Levedag
November 2016 Director, Institute of Flight Systems
German Aerospace Center
xi