News

1

Issue No. 9, May 2000

European Transonic Windtunnel GmbH

Ernst -Mach -Strasse D -51147 Köln

DaimlerChrysler Aerospace Airbus Half Model in the ETW Test Section

ETW has recently completed a series ofhalf model commissioning and cali-bration tests and is now able to offer thissystem to customers for production anddevelopment testing over the completeoperational envelope. This marks a

Half Model Testing Capabilitysignificant milestone in the expansionof the testing capabilities at ETW,providing the ability to test at low speedand high speed conditions over a widerange of Reynolds numbers up to flightconditions.

In June 1999 ETW started the first halfmodel commissioning and calibrationactivities in the tunnel. First experienceswere gained with this new technique inthe following months by using two dif-ferent models in the commissioning,calibration and validation phases of thehalf model concept.

DaimlerChrysler Aerospace Airbusprovided the model shown here for thepurposes of validating the ETW halfmodel system against their existing lowspeed database. This model is equippedwith adjustable slats and flaps to enablerepresentation of various high liftconfigurations together with a cleanconfiguration suitable for testing atconditions throughout the entireenvelope. During this initial validationseries the model was tested at incidencesup to and beyond maximum lift at lowspeed for a substantial Reynolds numberrange. The model was also tested at highspeed over a range of incidences up tobuffet onset at flight Reynolds numbers.

The ability to test over such an extensiverange of conditions is unique withinEurope. The data quality obtained todate has been demonstrated to be similarto full model data and this, in itself, is asignificant achievement at such an earlystage in the development of the halfmodel system. The lessons learnt fromthese early tests have helped to furtherdevelop the system, to establish appro-priate techniques that can be used toacquire high quality test results, and toachieve levels of productivity compati-ble with commercial operation.

A thermally conditioned balance wasselected for the ETW half model systemprimarily for reasons of minimisingdevelopment risks, but also with a viewto achieving high levels of productivity.The essential aspect of this concept is theability to condition the balance to auniform temperature and then to control

4

PersonnelSuccessful Validation Test with theModel Active Damping System Wolfgang Burgsmüller

Wolfgang Burgsmüller was appointedManaging Director of ETW GmbH atthe end of January 2000 following theretirement of Jean F. Moutte.

Mr. Burgsmüller was previously withDaimlerChrysler Aerospace Airbus inBremen, where he worked in the FlightPhysics department.

In recent years, amongst other duties,he has successfully coordinated severalEC-funded research programmes inaerodynamics.

Mr. Burgsmüller’s association withETW spans some 25 years. His initialinvolvement was in the early studiesand planning for the facility and, since1989, he was a member of the ETWTechnical Committee which counselsand advises ETW management on behalfof the European aerospace industry. Inhis new position as Managing Directorat ETW, Mr. Burgsmüller is supportedby Jean-Pierre Hancy, Manager Opera-tions, and Dr. Gerhard Hefer, ManagerAerodynamics and Projects.

Issue No. 9, May 2000

The High Load Range Unit of the ModelActive Damping System (ADS) deve-loped by ETW in co-operation withERAS GmbH was tested successfullyin January 2000 when it was used withthe ETW Reference Model.

Figure 1 presents the basic set-up of thesystem. It is installed bet-ween the flanges of the six-component strain gaugebalance and the sting, in thesupport line of the windtunnel model.

14 piezo ceramics capable ofbearing the load are simulta-neously excited to attenuatevibrations in 5 degrees of free-dom (without roll).

The design has taken intoaccount the special require-ments of modularity, limitedspace, high load levels anddifferent eigenfrequenciesdue to different test assemblyconfigurations.

The test programme perfor-med during the validationtest included stepwise increa-ses in dynamic pressure up to89 kPa at temperatures of294 K, 185 K, and 120 K

ETW News is issued byETW GmbH,Ernst-Mach-Strasse,D-51147 Cologne.http://www.etw.de

Editor: U. Walter,Tel.: +49 (0) 2203 609 115Fax: +49 (0) 2203 609 124uw@etw.de

Print: Druckerei Thierbach, Mülheim/Ruhr

Figure 1: Active Balance Interface

Figure 2: Level of Z & X Accelerations

which resulted in a Reynolds numberrange from 3x106 to 26x106.

At each condition, two polars weremeasured, one with the ADS inactiveand one with the system active. Theresult of these comparisons at highReynolds number is presented in figure 2.

etwnews09_2000_b.p65 03.08.00, 12:302-3

3

Aerospatiale Matra A340 ModelFin Sting and Pressure Plotted Wing Tests

Two different configurations of an A340model of Aerospatiale Matra were usedin tests during 1999.

In June, a co-operative fin sting testcampaign was successfully completed.The test assembly is presented in figure 1.

During test preparation, ETW devised aspecial sealing system for the fin stingassembly, which was successfullyadapted for the cryogenic test conditionsand to the demanding requirements onaccurate drag measurements. Valuableexperience was gained with model

coatings and their influence on theaerodynamic data.

The November test campaign with apressure plotted wing assembly also usedthe technique of model coating forfurther infra-red images through the

Issue No. 9, May 2000

2

Half Model Testing Capability (Continued)

The results achieved with the new systemhave been very promising throughoutthe complete test envelope. An exampleof the short term repeatability is presentedin Figure 2 for a Mach number of 0.6, atemperature of 120 K, and a total pressureof 300 kPa. Under these test conditionsthe standard deviation of the dragcoefficient was well within 1 drag count.Similar levels have also been demon-strated for both medium term and longterm repeatability. The half model systemhas also been used successfully at lowspeed and at reduced levels of dynamicpressure where balance stability stronglyinfluences the quality of results.

A significant advantage of this conceptis that temperature changes in the tunnelcan be completed rapidly, providing thatthe model is designed accordingly, withno additional overhead required forbalance conditioning prior to a test run.The only overhead that may be requiredis a few minutes of run time in order tocondition the model surface temperatureand avoid any boundary layer effects.This aspect has been demonstrated duringearly model tests and a typical test

the temperature to close tolerances inde-pendent of ETW's variable temperatureoperating environment.

In practice, this concept has been shownto work effectively and the resultingbalance temperature stability is impres-sive, even at cryogenic conditions, asdemonstrated in Figure 1. These stablecharacteristics are the key to the successof ETW's half model system and it is inthis area that significant developmentshave been made.

The balance has been designed for acombined loading in normal force of55 kN, pitching moment of 4.4 kNm andaxial force of 5.5 kN. Accuracy is specifiedas a complex function of the combinedoperating loads. For normal force, axialforce and pitching moment the accuracyis 0.1 % of the maximum load over 50 to100 % of the range and 0.05 % below50 %.

Issue No. 9, May 2000

Figure 1

Figure 2 (Results from ETW Commissioning Model)

News in BriefPSI Upgrade

ETW have recently completed amajor upgrade of all their PSImultiport pressure measurementand flow reference systems andare now running the most currentfirmware versions.

New Balance

The procurement of a new straingauge balance, for after-bodytesting of transport aircraft, isprogressing well with the anti-cipated delivery by the middle ofthis year.

Dynamic Data System

ETW recently took delivery of adynamic data acquisition sys-tem. This system allows highspeed data acquisition (up to50,000 samples/sec for 32 chan-nels) and real time, on-line dis-plays in engineering units andFFT. It also comes complete witha very comprehensive data toolkit to enable off-line data analysis.

This article forms an extract from amore comprehensive document whichis available from ETW on request,(please contact UsoWalter, uw@etw.de)

On 1 January 2000, Members of the ETW Supervisory Board were:France

ICA Xavier Bouis, Director, Large Technical Facilities,ONERA, Châtillon

ICA André Brémard, General Directorate of Armament,DGA/DSP, Paris

ICA Hervé Moraillon, General Directorate of CivilAviation, DGAC/DPAC, Paris

Great Britain

Dr. David E. Mowbray, Assistant Director, Civil & Inter-national Programmes, DERA, Farnborough

Dr. Raymond C. Kingcombe, Deputy Director, Techn.Partnership, Aerosp. & Defence Technology, DTI, London

Germany

Prof. Dr.-Ing. Heinz Körner, Director, Institute forDesign Aerodynamics, DLR, Braunschweig

Dr. Hans-Martin Spilker, Superior Counsellor, FederalMinistry for Education and Research, Bonn

Prof. Dipl.-Ing. Volker von Tein, Member of theExecutive Board, DLR, Köln

The Netherlands

Dr. Ir. Bernardus M. Spee, Director General, NLR,Amsterdam

Ir. Henk N. Wolleswinkel, Deputy Director General,Dutch Civil Aviation Authority, Den Haag

In total more than 300 infra-red imageswere taken with two standard IR-camerasof the wing upper and lower surfaces, thehorizontal tailplanes and the fin. Thetest conditions were varied from ambienttemperatures down to about 220 K, which

is the limit for the standard IR-cameras,and up to 450 kPa in total pressure.

The specially developed CRYSTAL IR-camera was then successfully used forthe low temperature range down to120 K resulting in chord Reynolds num-bers up to 37 Mio.

The tests were completed to the Client’ssatisfaction and the excellent resultswere presented to Airbus Industry inFebruary 2000.

Figure 1

Figure 2

complete operating envelope of ETW.

A special coating technique for pressuretapped wings was effectively appliedand figure 2 presents a zoomed-in viewof one row of pressure taps (Ø=0,1 mm)on the upper wing surface.

Figure 3 Typical Operating Schedule

schedule based on this experience isprovided in Figure 3.

etwnews09_2000_b.p65 03.08.00, 12:304-5

3

Aerospatiale Matra A340 ModelFin Sting and Pressure Plotted Wing Tests

Two different configurations of an A340model of Aerospatiale Matra were usedin tests during 1999.

In June, a co-operative fin sting testcampaign was successfully completed.The test assembly is presented in figure 1.

During test preparation, ETW devised aspecial sealing system for the fin stingassembly, which was successfullyadapted for the cryogenic test conditionsand to the demanding requirements onaccurate drag measurements. Valuableexperience was gained with model

coatings and their influence on theaerodynamic data.

The November test campaign with apressure plotted wing assembly also usedthe technique of model coating forfurther infra-red images through the

Issue No. 9, May 2000

2

Half Model Testing Capability (Continued)

The results achieved with the new systemhave been very promising throughoutthe complete test envelope. An exampleof the short term repeatability is presentedin Figure 2 for a Mach number of 0.6, atemperature of 120 K, and a total pressureof 300 kPa. Under these test conditionsthe standard deviation of the dragcoefficient was well within 1 drag count.Similar levels have also been demon-strated for both medium term and longterm repeatability. The half model systemhas also been used successfully at lowspeed and at reduced levels of dynamicpressure where balance stability stronglyinfluences the quality of results.

A significant advantage of this conceptis that temperature changes in the tunnelcan be completed rapidly, providing thatthe model is designed accordingly, withno additional overhead required forbalance conditioning prior to a test run.The only overhead that may be requiredis a few minutes of run time in order tocondition the model surface temperatureand avoid any boundary layer effects.This aspect has been demonstrated duringearly model tests and a typical test

the temperature to close tolerances inde-pendent of ETW's variable temperatureoperating environment.

In practice, this concept has been shownto work effectively and the resultingbalance temperature stability is impres-sive, even at cryogenic conditions, asdemonstrated in Figure 1. These stablecharacteristics are the key to the successof ETW's half model system and it is inthis area that significant developmentshave been made.

The balance has been designed for acombined loading in normal force of55 kN, pitching moment of 4.4 kNm andaxial force of 5.5 kN. Accuracy is specifiedas a complex function of the combinedoperating loads. For normal force, axialforce and pitching moment the accuracyis 0.1 % of the maximum load over 50 to100 % of the range and 0.05 % below50 %.

Issue No. 9, May 2000

Figure 1

Figure 2 (Results from ETW Commissioning Model)

News in BriefPSI Upgrade

ETW have recently completed amajor upgrade of all their PSImultiport pressure measurementand flow reference systems andare now running the most currentfirmware versions.

New Balance

The procurement of a new straingauge balance, for after-bodytesting of transport aircraft, isprogressing well with the anti-cipated delivery by the middle ofthis year.

Dynamic Data System

ETW recently took delivery of adynamic data acquisition sys-tem. This system allows highspeed data acquisition (up to50,000 samples/sec for 32 chan-nels) and real time, on-line dis-plays in engineering units andFFT. It also comes complete witha very comprehensive data toolkit to enable off-line data analysis.

This article forms an extract from amore comprehensive document whichis available from ETW on request,(please contact UsoWalter, uw@etw.de)

On 1 January 2000, Members of the ETW Supervisory Board were:France

ICA Xavier Bouis, Director, Large Technical Facilities,ONERA, Châtillon

ICA André Brémard, General Directorate of Armament,DGA/DSP, Paris

ICA Hervé Moraillon, General Directorate of CivilAviation, DGAC/DPAC, Paris

Great Britain

Dr. David E. Mowbray, Assistant Director, Civil & Inter-national Programmes, DERA, Farnborough

Dr. Raymond C. Kingcombe, Deputy Director, Techn.Partnership, Aerosp. & Defence Technology, DTI, London

Germany

Prof. Dr.-Ing. Heinz Körner, Director, Institute forDesign Aerodynamics, DLR, Braunschweig

Dr. Hans-Martin Spilker, Superior Counsellor, FederalMinistry for Education and Research, Bonn

Prof. Dipl.-Ing. Volker von Tein, Member of theExecutive Board, DLR, Köln

The Netherlands

Dr. Ir. Bernardus M. Spee, Director General, NLR,Amsterdam

Ir. Henk N. Wolleswinkel, Deputy Director General,Dutch Civil Aviation Authority, Den Haag

In total more than 300 infra-red imageswere taken with two standard IR-camerasof the wing upper and lower surfaces, thehorizontal tailplanes and the fin. Thetest conditions were varied from ambienttemperatures down to about 220 K, which

is the limit for the standard IR-cameras,and up to 450 kPa in total pressure.

The specially developed CRYSTAL IR-camera was then successfully used forthe low temperature range down to120 K resulting in chord Reynolds num-bers up to 37 Mio.

The tests were completed to the Client’ssatisfaction and the excellent resultswere presented to Airbus Industry inFebruary 2000.

Figure 1

Figure 2

complete operating envelope of ETW.

A special coating technique for pressuretapped wings was effectively appliedand figure 2 presents a zoomed-in viewof one row of pressure taps (Ø=0,1 mm)on the upper wing surface.

Figure 3 Typical Operating Schedule

schedule based on this experience isprovided in Figure 3.

etwnews09_2000_b.p65 03.08.00, 12:304-5

News

1

Issue No. 9, May 2000

European Transonic Windtunnel GmbH

Ernst -Mach -Strasse D -51147 Köln

DaimlerChrysler Aerospace Airbus Half Model in the ETW Test Section

ETW has recently completed a series ofhalf model commissioning and cali-bration tests and is now able to offer thissystem to customers for production anddevelopment testing over the completeoperational envelope. This marks a

Half Model Testing Capabilitysignificant milestone in the expansionof the testing capabilities at ETW,providing the ability to test at low speedand high speed conditions over a widerange of Reynolds numbers up to flightconditions.

In June 1999 ETW started the first halfmodel commissioning and calibrationactivities in the tunnel. First experienceswere gained with this new technique inthe following months by using two dif-ferent models in the commissioning,calibration and validation phases of thehalf model concept.

DaimlerChrysler Aerospace Airbusprovided the model shown here for thepurposes of validating the ETW halfmodel system against their existing lowspeed database. This model is equippedwith adjustable slats and flaps to enablerepresentation of various high liftconfigurations together with a cleanconfiguration suitable for testing atconditions throughout the entireenvelope. During this initial validationseries the model was tested at incidencesup to and beyond maximum lift at lowspeed for a substantial Reynolds numberrange. The model was also tested at highspeed over a range of incidences up tobuffet onset at flight Reynolds numbers.

The ability to test over such an extensiverange of conditions is unique withinEurope. The data quality obtained todate has been demonstrated to be similarto full model data and this, in itself, is asignificant achievement at such an earlystage in the development of the halfmodel system. The lessons learnt fromthese early tests have helped to furtherdevelop the system, to establish appro-priate techniques that can be used toacquire high quality test results, and toachieve levels of productivity compati-ble with commercial operation.

A thermally conditioned balance wasselected for the ETW half model systemprimarily for reasons of minimisingdevelopment risks, but also with a viewto achieving high levels of productivity.The essential aspect of this concept is theability to condition the balance to auniform temperature and then to control

4

PersonnelSuccessful Validation Test with theModel Active Damping System Wolfgang Burgsmüller

Wolfgang Burgsmüller was appointedManaging Director of ETW GmbH atthe end of January 2000 following theretirement of Jean F. Moutte.

Mr. Burgsmüller was previously withDaimlerChrysler Aerospace Airbus inBremen, where he worked in the FlightPhysics department.

In recent years, amongst other duties,he has successfully coordinated severalEC-funded research programmes inaerodynamics.

Mr. Burgsmüller’s association withETW spans some 25 years. His initialinvolvement was in the early studiesand planning for the facility and, since1989, he was a member of the ETWTechnical Committee which counselsand advises ETW management on behalfof the European aerospace industry. Inhis new position as Managing Directorat ETW, Mr. Burgsmüller is supportedby Jean-Pierre Hancy, Manager Opera-tions, and Dr. Gerhard Hefer, ManagerAerodynamics and Projects.

Issue No. 9, May 2000

The High Load Range Unit of the ModelActive Damping System (ADS) deve-loped by ETW in co-operation withERAS GmbH was tested successfullyin January 2000 when it was used withthe ETW Reference Model.

Figure 1 presents the basic set-up of thesystem. It is installed bet-ween the flanges of the six-component strain gaugebalance and the sting, in thesupport line of the windtunnel model.

14 piezo ceramics capable ofbearing the load are simulta-neously excited to attenuatevibrations in 5 degrees of free-dom (without roll).

The design has taken intoaccount the special require-ments of modularity, limitedspace, high load levels anddifferent eigenfrequenciesdue to different test assemblyconfigurations.

The test programme perfor-med during the validationtest included stepwise increa-ses in dynamic pressure up to89 kPa at temperatures of294 K, 185 K, and 120 K

ETW News is issued byETW GmbH,Ernst-Mach-Strasse,D-51147 Cologne.http://www.etw.de

Editor: U. Walter,Tel.: +49 (0) 2203 609 115Fax: +49 (0) 2203 609 124uw@etw.de

Print: Druckerei Thierbach, Mülheim/Ruhr

Figure 1: Active Balance Interface

Figure 2: Level of Z & X Accelerations

which resulted in a Reynolds numberrange from 3x106 to 26x106.

At each condition, two polars weremeasured, one with the ADS inactiveand one with the system active. Theresult of these comparisons at highReynolds number is presented in figure 2.

etwnews09_2000_b.p65 03.08.00, 12:302-3