Configuration Aerodynamics: Past - Present - Future

First NASA/Industry HSR Configuration Aerodynamics Workshop I lift r I

CONFIGURATION AERODYNAMICS

Past- Present- Future

Richard Wood, NASA LaRC Shreekant Agrawal, MDA Dan Bencze, NASA ARC Bob Kulfan, BCA Doug Wilson, BCA NASA, LaRC February 27, 1996 The Configuration Aerodynamics (CA) element of the High Speed Research (HSR) program is managed by a joint NASA and Industry team, referred to as the Technology Integration Development (ITD) team. This team is responsible for the development of a broad range of technologies for improved aerodynamic performance and stability and control characteristics at subsonic to supersonic flight conditions. These objectives are pursued through the aggressive use of advanced experimental test techniques and state of the art computational methods. As the HSR program matures and transitions into the next phase the objectives of the Configuration Aerodynamics ITD are being refined to address the drag reduction needs and stability and control requirements of High Speed Civil Transport (HSCT) aircraft. In addition, the experimental and computational tools are being refined and improved to meet these challenges.

The presentation will review the work performed within the Configuration Aerodynamics element in 1994 and 1995 and then discuss the plans for the 1996-1998 time period. The final portion of the presentation will review several observations of the HSR program and the design activity within Configuration Aerodynamics.

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MISSION

• Advance the HSCT aerodynamic performance, stability and

control, and propulsion airframe integration technologies in

the flight regime outside the terminal control area.

• Maintain close continuous technology integration with other

High Speed research airframe and propulsion technology

elements.

The mission of the Configuration Aerodynamics (CA) Integrated Technology Development (ITD) Team has two parts; first, it is to develop and improve aerodynamic performance, stability and control and propulsion airframe integration technologies for flight conditions outside the terminal control area and second, is to maintain close continuous coordination and technology integration activities with other HSR teams. Specific teams that the CA ITD coordinates with are the Propulsion Airframe Integration Working Group, Stability and control Working Group and the Technology Integration, High Lift, Flight controls, Inlet and Nozzle ITD Teams.

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ORGANIZATIONAL AND TECHNICAL DIVERSITY

THE CONFIGURATION AERODYNAMIC TEAM: • NASA - LaRC and ARC • Industry - Boeing and McDonnell Douglas Aerospac¢ - L-M, N-G, Dynacs, Eagle, Vigyan, CSC, AS&M, RIACS, DEI, Microcraft, Sterling...

• Academia - Princeton, Old Dominion, George Washington TECHNICAL RESPONSIBILITIES: • Aerodynamic Design • Aerodynamic Performance • Stability and Control • Propulsion/Airframe Integration • Computation Fluid Dynamic Tool Development • Experimental Fluid Dynamic Tool Development • .................. ,,,, • ............. ,°,,,,,,, • ,,,, ..................

In support of the teams mission, the CA ITD has developed a diverse organizational technical team which is responsible for developing a broad range of technologies. The diversity of the team is critical to ensure that all possible technologies are considered within the program.

As indicated above the diverse technical responsibilities requires that efficient teaming occur and that multi-use tools be employed to maximize the resources available to the team. An area of particular concern is aerodynamic design and performance improvements. This area has been and will continue to be centered around the development of drag reduction technologies and methods for design.

_ First NASA/Industry HSR Configuration Aerodynamics Workshop PCD I MILESTONES IT_SKS'_I FY 1994 1 1995 1996 1997 1998 1999 2000 2001 Mi_t_ ._lndustty Prelim.Concept • Prelim. Config.. • Firm Config._, I I Crui=e Wing W/N/D AlL Cpt. Multi:Pt Elu. Des. Data Base 4.3,1 | Meth. Valid Inleg Data Base Wing_ac Dee Me_. Av_ for Integ Config IAero_am,_= RefH Meff_. A_eu. =_re_im P,,pt Aeroprop' Prel. Cpt Integ Aeroel-'- PerffCtr_ Select _eJect Elfects AmNm= /1¢_= Trim Perf Dea Me_ I I I I 4.3.1.1 Cmiae W'_ng Point [:Nm. Vi=. Dyn. Ela=_ DeG.

Meth Valid Meth. Valid Stab. Code Meth. Avail CFD iAdapt_tion i t kki_. Assess. ElutJc Multi-Pt, AC Wt_/Nac •" , ...... T 4.3.1.2 RefHPw//Ctfls Aftbody PLDeI. M_ Mu_-PLDu. PreLCpt. DataBuefm Data BaBe Clooure Data BaBe Data Bue AIIIlU lntag. Conflg.

....... I i Conflguratk>n Eviduation W_Ou. Trineor_'Rap Ref H Dyn Aero_a_dJ¢ E't_dc AC Data Bue Data Ba_ Stab Data Bmm Supemonic Sere Meth. DmtaBue ! ,, 4..t.1 .,1 Arc Co_copt Assessment _tern-,te i__ Concept Studies Data _ fo_ Ctd_Ptanform 43.1.4 StaticI_let N/D Deign [ StaSc Inlet Inlet Bleed/Bypass _ropuLslon Ur_tart Inleg. | Ur_tart Method Inlemctlons _Jdrame ntegmtion RefHlnlet J Wing Noz,de Dynamic Inlet J Imograted Flowf_d .[ ,, Jet Int_actiom .... Urn= J Tmnsonk_Pwf.

i4.3.1.5 RefHPorf. PretimCpL AJt.Cpt. Aecoetall_c Pmlim. Cpt. Aeroe_asticDe=.

Aerodynamic AMe_ Sdect Aue_ Wing Shi_oe_ _ ] Me_. v=_.

Integration Sty- wk _,c_ ,.,.s_c' A;o_o,, .,,.,'_ T,,,:_,,,_ Dmign Perf. _ _ Assess Auees-II Rklkemaeel The 1994-2001 CA program is outlined above in the milestone chart.

The 1994-1995 period was managed according to the Planning and control Document(PCD) I. As shown above, the PCD I plan contained five sub-tasks and 14 milestones which were active for the PCD I period.

A major portion of the program in this time period was the assessment of the Reference H configuration which served as the program baseline for technology developments. In addition to the Reference H focus a limited amount of research was directed at Alternate concepts within sub-tasks 3 and 5. The alternate work focused on alternate control effectors for improved stability and control and planform studies for drag reduction.

First NASA/Industry HSR Configuration Aerodynamics Workshop I I I II

94 - 95 EXPERIMENTAL RESEARCH

• # of Facilities 5

• # of Models 10

• # of Tests 30

• # of Configurations 600

• # of Data Points 300,000

8 ARC

.#of

Enginyears 4 MDA

4 BCA

15 LaRC

2 LKHD

A significant portion of the effort in support of PCD I was an extensive experimental test program as outlined above. The CA ITD made use of 5 wind tunnel facilities; 2 at NASA Ames and 3 at NASA Langley. The test activities produced over a quarter million data points, 70% of those obtained were in support of stability and control and 30% in support of drag reduction. As with all aspects of the CA program, the success of the experimental activity relied on a diverse group of researchers from NASA Langley, NASA Ames, McDonnell Douglas, Boeing, and Lockheed which comprised 33 engineering work years.

First NASA/Industry HSR Configuration Aerodynamics Workshop

PCD I COMPUTATIONAL TOOLS

VISCOUS: INVISCID: • AERO2S • CFL3D • WINGDES • GCNSfv • OVERFLOW • TRANAIR • PAB3D • STUFF • AIRPLANE • TLNS3D • CFL3D • FLO57, 67, 87 • TLNS3D • USM3D CONTRIBUTING ORGANIZATIONS: • NASA - LaRC and ARC • Industry - Boeing and McDonnell Douglas Aerospace - L-M, N-G, Vigyan, AS&M, RIACS • Academia - Princeton Configuration Aerodynamics activity also utilized a wide range of computational tools for both aerodynamic analysis as well as design.

Depicted above are the inviscid and viscous computational tools employed and the organizations which have contributed to the development of those tools. The inviscid methods range from the linear tools(AERO2S, WINGDES), to full potential (TRANAIR), to the Euler methods (AIRPLANE, CFL3D, etc..). The inviscid methods have served as the workhorses of the program to date due to the reduced grid generation time and computational resource costs. These methods have proven to be extremely robust and accurate for attached flow conditions, especially at supersonic speeds. The viscous methods employed within CA have also been fairly diverse in technology covering a wide range of solution methodology as weU as gridding methodology. It is critical that an adequate assessment of the viscous tools be conducted because the importance of viscous analysis and design is expected to increase significantly during the next program period.

As mentioned previously, aerodynamic design is a major activity within the program. Of the methods listed above the primary aerodynamic analysis tools used in the design process are TRANAIR, FLO57-87, CFL3D(euler and Navier stokes) and OVERFLOW.

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DESIGN PROCESS COMPONENTS

GEOMETRY MODELING ANALYSIS TOOL • POTENTIAL • ID WITH SMOOTHING • EULER • 2D ANALYTIC WITH • NAVIER STOKES SMOOTHING • 3D ANALYTIC OPTIMIZATION TOOL • NUMERICAL • KNOWLEDGE BASED The aerodynamic design activities within the Configuration Aerodynamic activity have required the development of design process tools in the three areas indicated above. The areas in which design process tools are being developed are aerodynamic analysis, geometry modeling, and optimization. As previously indicated nonlinear design activities within CA have employed aerodynamic analysis tools which range from full potential to Euler to Navier-Stokes. These tools have been coupled with a variety of geometry modeling packages as indicated and have been driven by numerical optimization tools as well as knowledge driven processes. The success of the design process also requires that the above componenets be linked within a design concept or philosophy. The selected design philosophy will bias the selection of the aerodynamic analysis tool and the geometic model. This underlying design philosophy will be the driving force in a knowledge based design process.

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_,_,_._ ,,m

PCD I AERODYNAMIC SHAPE DESIGN STUDIES

_WING /BODY/ WING / BODY with "" CONFIGURATION NACELLE / DIVERTER effects

_)

("" _ NACELLE / DIVERTER / - VISCOUS ANALYSIS TOOL INVISCID i i i|ml NUMERICAL BASED -< -- - KNOWLEDGE BASED OPTIMIZATION TOOL PIECEWISE - 3-D ANALYTIC GEOMETRY ANALYTIC MODELING

\ ./ x... )

In support of the PCD I design activities the CA ITD executed three distinctly different design proceses in performing four nonlinear aerodynamic cruise point shape design studies. The design processes are outlined above, as noted by the circled elements. Each design process contains four elements; the configuration under investigation, the aerodynamics analysis tool, the optimization tool, and the geometric model. As shown in the sketch the design processes used were two numerical based optimization process which utilized inviscid methods with a piecewise geometric model. The primary difference between the inviscid design processes was that one approach used the pressure field from the nacelle/diverters and the second modeled the nacelle/ diverters in the design. The third process used was a viscous based design which employed a 3-D analytical geometric model and utilized a knowledge based optimization process to drive the design. As expected each of the four nonlinear aerodynamic cruise point shape design studies produced significantly different shapes yet obtained similar drag reductions from a baseline, linear-theory design.

First NASA/Industry HSR Configuration Aerodynamics Workshop PCD I TECHNICAL ACCOMPLISHMENTS • Validation tests of nonlinear supersonic cruise wing/body/nacelle/ diverter designs have shown up to 7cts of drag reduction.

• Experimental data show that Reynolds number and model aeroelastic effects are significant at subsonic cruise.

• Advanced experimental test techniques allow for drag measurementswith 1/2 count repeatability.

• Advanced computational methods consistently compare with experimental test results within 5%. Have demonstrated cruise drag predictions within 1.5 drag counts of experimental data.

The PCD I period was successful in satisfying the objectives of the program and laying the groundwork for the PCD II period. Specific accomplishments were: - Validation of the cruise point design processes. Test results verified a 7 count drag reduction.

- Identification of Reynolds number and aeroelastic effects at subsonic speeds.

- Development of advanced test techniques which allow drag to be measured within 1/2 count.

- Development of advanced computational methods with experimental accuracy.

_ First NASA/Industry HSR Configuration Aerodynamics Workshop

TECHNOLOGY CONCEPT SELECTION Nozzle Controls Aero Risk Engine Cycle Inlet Concept Config, PCD I MILESTONES Selection Selection Definition Selection Reduction Selection MS- 1 Design Method Adaptation MS-2 Analysis Method Adaptation MS-3 Wing/Body Design Data Base r MS-4 Ref H Performance and Control Data Base MS-5 Transonic Flap Data Base MS-6 Afterbody Closure Assessment ilW.----_,_ MS-7 Alternate Concept Assessment MS-8 Static Inlet UnsL_l Assessment MS-9 Inlet How Field Assessment -MS- l 0 Nacelle/Diverter Design and Intemmtion ¢w,,--- - MS-I 1 Wing/Body Design MS-12 RefH Aerodynamic Performance and S&C Assessment MS- 13 Alternate Control Concepts Assessment MS-14 Preliminary Concepts Assessmenl Criteria In addition to the technical accomplishments listed in the previous figure the CA activity also contributed to the definition of the Technology Concept Airplane(TCA). Shown above are the 14 active milestones during the PCD I period and their relationship to 6 critical decision gates in defining the TCA. The chart shows that CA activities and the technology developed played a significant role in the TCA development process, CA technology was especially evident in defining the configuration layout and the control effectors.

First NASA/Industry HSR Configuration Aerodynamics Workshop

PCD II M ESTONES

1996 1997 1998 1999 = = i ,,A+om; _Rek_ rech'nOlOgy ' Technology Concmpt k Conn_ur_ A_oo_na, mic Auwumenr pr +,_,z,,+ ' I - _ C_#gun_,_onD_'_ ,_ con_uraEon E_t_ ced El_Ric Inv.

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__2A

PtDe, h,..__._ _is .._....._ ; Inv Aeroelu 4.3.1.1 Nonlinear Rigid R_ _d Fu# Ana;-/sts R_gid Prop VtICOUlAeroe IS and Aeroelasti¢ Analysis A De_ .

C,_lltg F & M _ InducedEffects ,Jd L Ar,,alyab Method I • ; ; , I NonNnmuCmlso 4.3.1.2 Aerodynamic I Wtng Th_u,I I Multi-R+Des.

Pt Design Rigi¢Vlmx)u= Design Optlmlzldlon J_ ,_ LDes. M. "lt_od , opt. _.?=h..,/ l Rind _ lultl-Pt. Multi+R, I I 4.3.1.3 Nocelie/Dlverter i I I _eu Inltl AUIII Inkd Nozzkl Int, Design and Aldrame I_le_cafion mow _,,t,._. l.. J L._+=,+" , l Int_rltion

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I I 4.3.1.4 Technology Stabilityand A_e Concept Auwament 4.3.1.99 Task Y_r Review Planning and Coordination The next phase of the HSR program will cover the time period of 1996- 1998. This period will be governed by the Planning and Control Document (PCD) II and will be referred to as the PCD II period. The HSR program will redirect its focus over the next three years from the Reference H configuration to the Technology Concept Airplane. In support of this focus, the program has been rebaselined and the Configuration Aerodynamics ITD has restructured its program as indicated above. The PCD II program has been restructured into 4 technical sub-tasks and one planning sub-task. The CA program major deliverables are captured by the 8 level 3 milestones listed above. As noted in the milestones chart 6 of the 8 level 3 milestones are related to design tool development and drag reduction studies. The remaining 2 milestones support the assessment of the TCA and development of an aeroelastic analysis tool.

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PCD II WBS

4.3.1.! Nonlinear Rigid and Aeroelastic Analysis Method 4.3. I. 1.1 Rigid Full Configuration Force and Moments 4.3.1.1.2 Inviscid Aeroelastic Analysis 4.3.1.1.3 Viscous Aeroelastic Analysis 4.3. I. 1.4 Rigid Propulsion Induced Effects 4.3.1.2 Aerodynamic Design Optimization Capability 4.3.1.2.1 Nonlinear Cruise Point Design 4.3.1.2.2 Rigid Multi-Point Design Method Formulation 4.3.1.2.3 Rigid Viscous Multi-Point Design 4.3.1.2.4 Elastic Inviscid Multi-Point Design 4.3.1.3 Nacelle/Diverter Design and Airframe Integration 4.3.1.3.1 Nacelle/Diverter Integration 4.3.1.4 Technology Concept Assessment 4.3.1.4.1 Aerodynamic Performance 4.3.1.4.2 Stability and Control 4.3.1.4.3 Propulsion Induced Effects 4.3.1.99 Task Planning and Coordination Depicted above is the work breakdown structure(WBS) for the CA PCD II period.

_ First NASA/Industry HSR Configuration Aerodynamics Workshop PCD II GOALS Approach: • To acquire a comprehensive experimental and computational aerodynamic performance, stability and control data base for the HSR Technology Concept, adapt and validate point design methods and multidisciplinary design optimization methods, design and assess alternate concepts, adapt and validate methods for multi-point aeroelastic design of airframes.

Deliverables: • Aerodynamic data base for HSR Technology Concept.

• Validated aerodynamic analysis methods for HSCT concepts.

• Validated cruise-point and multi-point aeroelastic design methods.

• Validated aerodynamic analyses and design method for propulsion airframe integration.

The CA activity has identified drag reduction as the highest leverage technology contribution towards the development of an economically viable HSCT. Based upon this fact the program is heavily biased in this direction, as indicated above. The approach to be used in the PCD II period is similar to that in PCD I, the CA activity will rely heavily on experimental activity for design validation and for TCA assessment. The design activities will include the development of technologies for point design and multi-point design including the effects of aeroelastics.

The key deliverables during the PCD II period will be the assessment of the TCA, validation of design methods, including PAl design tools, and the development of advanced aerodynamic analysis methods which account for aeroelastic effects.

?_ First NASA/Industry HSR Configuration Aerodynamics Workshop

DESIGN ISSUES Critical Technologies Computational Methodolot, v Configuration _u_Zc.dmlau_ _. Support Interference • Efficient and Adaptive .. Wing Shape and Volume Gridding • Rn Effects • Fuselage Shape and Volume • Structural Modeling • Transition Fixing • Empennage Shape and Siz/ng • Power and Pnuematic Simulation • Aeroelastic Assessment • Control Effector Design • Foc¢ Accounting • Global/Analytic Design • Nacelle/Diverter Shape and Variables Integration • Measurement Accuracy • Advanced Turbulence • B. L. Management Techniques Models • Powered Testing Impact • 15 to 18 Cts Drag Reduction from Linear Theory Design • 87,000 to 120,000 lbs Reduction in TOGW • Reduced Uncertainty in Transonic and Supersonic Drag Reduction • Reduced Design Cycle Time • Impact: Planform Selection, Payload, Vehicle Size, Engine Cycle, Inlet and Nozzle Selection In the area of nonlinear aerodynamic shape design, there are a variety of critical configurations, experimental test techniques, and computational technologies which must be addressed if a viable design capability and thus a viable HSCT is to be developed. A listing of the most critical technologies are shown above. If the CA ITD is successful, it is expected that a 15-18 count drag reduction is achievable, from a linear theory design, which corresponds to a weight reduction up to 120,000 pounds. Another payoff to the development of these design technologies is a significant reduction in risk to Industry for product "go ahead" as well as a reduction in the design cycle time.

First NASA/Industry HSR Configuration Aerodyhamics Workshop 120000 IMPACT of AERODYNAMIC PERFORMANCE ON TECHNOLOGY CONCEPT MTOW 1OOO0O cruise 8OOOO Refined Nonlinear Cruise Point O Design 60O0O cruise Enhanced N_n_ .....

40OOO Cruise Point i Design _JD=4.3% Initial Nonlinear; 2OOOO Cruise Point Design 0 [ RF:FFRF:NCF I 1 g93 1994 1995 1996 1997 1998 Shown above is a graphical display of the expected L/D improvements and resulting weight reductions associated with the point and multi- point design activities. The chart shows that a 100% improvement in the drag reduction is expected in 1996 over that achieved in 1995. And by 1998 the CA activity is expected to triple the drag reduction over the 1995 level. This level of success is critically dependent upon highly effective teamwork and a sharing of all drag reduction technologies developed within the program. The design activity is also highly dependent upon the development of advanced test techniques in the areas of aeroelastics, Reynolds number effects and transition assessment.

_:_ First NASA/Industry HSR Configuration Aerodynamics Workshop PCD II EXPERIMENTAL ACTIVITY Model Number WBS Model Facility Description l . _ 1_7% WtB/Nw ] ............. 1 4.31ii2 Transo_ and superson¢ _w _ld rake ...... uPw'r: 16, I ...... l 1,7% W/B/N* i i i 1 UPWT ' • " 7,,aw/s/N w ..... _;_ :w_/_ I 1.7% W/B/N/Emp Tech Cpt Full ConfiQ Design UpWT. 16' w pressures 5 4.3.1.2 1.7% W/B/N/Flaps UPWT. 16' w pressures Tech Cpt Mufti-Point Design, MP 1 4.3.1.2 1.7% W/B/N w UPWT. 16' pressures Tech Cpt Multi-Point Design. MP 3 7 4.3.1.2 1.7% W/B/N/Flaps UPWT_ 16' w pressures B 4.3.1.2 Tech Cpt Multi-Point Design, MP 4 1.7% W/B/N w UPWT Dressures Tech Cpt Aeroelastic, Supersonic 9 4.3.1.2 1.7% W/B/N w pressures Tech Cpt Aeroelastlc, Transonic(shape #1 ) 1 _' 10 4.3.12 1.7% W/B/N w Tech Cpt Aeroelastic, Transonic(shape #1 ) 1 _' 11 4.3.1.2 .,Ip-essums _ NiD combi_l_ (3 sets) , i:i. ..... : : _ I [ ...... ..... ........

:[i3:43:13 i No_ boattatl drag I .....

;. ,1,4 ; 4.3_i,3 ZD Nozzles ..... "_" UPWT Nacelle and 15 4.3.1.3 N/D combinations (3 sets) upw'r diverters In support of the design activity there are a large number of wind tunnel models and test activities scheduled. These models will be used to obtain the necessary data to validate the design activities and the drag reductions obtained. Listed above are the PCD II models for support of configuration and nacelle/diverter design activities. The shaded areas correspond to models that are to be fabricated and tested in 1996. The remaining models are to be designed, fabricated, and tested in 1997 and 1998.

First NASA/Industry HSR Configuration Aerodynamics Workshop ANALYSIS ISSUES Critical Technologies Test Techniques E xperhnental Aerodvnamies • Viscous Modeling ., Supersonic Cruise Drag j Support Interference • Aeroelastlc Effects • Rn Effects • Transonic Cruise Drag • Aeroelastlc Measurements • Accuracy, Robus/ne_, Efficient • Trim Drag • Powered Effects • Transition Modeling • Stability and Control • Powered Models • Efficient Gridding • Rn Effects • Power Effects Impact • Reduce Program Risk Due to Uncertainty in Aircraft Performace and S&C may: - Size the Aircraft • Define Cycle and Pianform - Limit Payload and Range • Develop Confidence in Aircraft Performance Prediction Capability • Understand Methods and C_t for Accurate Data • Allow Extrapolation to Flight Conditions The second major area of work within CA for PCD II is the aerodynamic analysis/assessment of TCA. This area of work covers performance, stability and control, and propulsion effects. As with the design area, there are a number of critical technologies in experimental aerodynamics, experimental test techniques and computational analysis methods. The assessment of the TCA will rely heavily upon both advanced experimental studies as well as advanced computational activities. Several areas that will recieve close scutiny from an experimentral view will be aeroelastics, bounday-layer tripping and transition, and support interference. On the computational side the program will focus on aeroelastics, turbulence modeling, and efficient gridding. The payoff to these technologies is a reduction in program risk and the improved capability of extrapolating the results to flight.

_ First NASA/Industry HSR Configuration Aerodynamics Workshop

PCD II EXPERIMENTAL ACTIVITY Model i Number WBS Model Fllclllt_" Description i :: :t6 4,3;1:,t Gdt test 0r0qr=m .......... UPWT. NTF Exl_ _e UPWT. NTF UPWT. 16'. NTF 1.7__IBt_qZEmo 19 4.3.1.4 Tech Cpt aftbody closure _ii i +:+al .... ,+__1:4 :: : 22 4.3.1.4 Tech Cpt powered semi-span 11' WIBIN/Emp 2;] 4.3.1.4 Tech Cpt ref semi-span ] ]' W/B/N/Erno In support of the analysis activity there are a large number of tests scheduled for the set of wind tunnel models listed above. These models will be used to obtain the necessary data to assess the TCA and provide the ground based corrections for scaling the wind tunnel data to flight conditions. The shaded areas correspond to models that are to be fabricated and tested in 1996. The remaining models are to be designed, fabricated and tested in 1997 and 1998.

_" First NASA/Industry HSR Configuration Aerodynamics Workshop

OBSERVATIONS

The previous figures and text discussed the details of the PCD I activity(past) and the PCD II activity (present). The following set of figures will highlight some personal observations from the past and will reflect on the needs of the HSR program now and in the future.

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\ \

\ \ The HSR program, and especially the Configuration Aerodynamics element, has gone through significant change over the past 24 months.

In 1994, the CA activity consisted of each organization operating independent of one another within the influence of the HSR program structure. As the program evolved, the CA activity had periods of alignment and rnisalignment from both a technical and programmatic perspective. The graphic above depicts the 1994 perspective.

.j .,S_ First NASA/Industry HSR Configuration Aerodynamics Workshop In 1995, the program adopted the PCD format, implemented team work and consensus, and began the use of schedules. These changes brought the focus of CA into alignment with the HSR program and all activities within CA centered around the HSR program. The situation had improved dramatically however it was still less than that required for program success.

_ First NASA_ndustry HSR Configuration Aerodynamics Workshop !

The graphic shown above depicts a desirable situation for success within the program. The CA team has a single vision and operational space.

This environment must maintain the characteristics of each individual organizations and must operate within the HSR program objectives and policies.

Once the programmatic aspects are achieved the CA ITD can then create a common vision for design activities. The design activity within CA is the prime focus and as such the HSR program is relying heavily on the success of CA.

However, it must be recognized that the feasible design space being investigated by CA can not be characterized by a single design approach within the HSR program but is more likely represented by a family of design approaches which are not physically connected(past). The CA ITD must assess the true character of the design space in order to find success in the drag reduction efforts.

-./ First NASA/Industry HSR Configuration Aerodynamics Workshop

f,/, SUPERPOSmON OFEFFECTS i * WAVE DRAG, VORTEX DRAG, " SKIN FRICTION DRAG, DRAG _ DUE-TO-LIFT .........

_ .AREADISTRn_U'nONS I AERODYNAMIC \.. J OBSERVATIONS .Z_ I_RING SHEAR AND ):_ " : NORMAL FORCES ......

_ AND NATURAL FLOW / AERODYNAMIC OBSERVATIONS Perhaps the most important question which must be answered is: What are nonlinear aerodynamics? And what does it mean to conduct nonlinear aerodynamic shape design. Shown above are two possible views and answers to this question. Shown on top is the traditional approach in which the explanations are provided in the standard framework and shown below is an atypical set of explanations to the same question. Each of these explanations carry with it bias errors associated with the meaning of the words and the history of the individual. However, if CA is to be successful in reducing the drag through nonlinear design then a common goal must be developed, this requires a common language. The situations of solving a linear problem with a nonlinear method or the solving a nonlinear problem with a linear method must be avoided if progress is to be made.

7_._ First NASA/Industry HSR Configuration Aerodynamics Workshop OBSERVATIONS • The "REAL" nonlinear drag reduction boundaries must be identified and quantified.

- >100% aerodynamic thrust is achievable!

- Are Linear Theory based boundaries relative?

• Multi-Point design activity is critical to understanding the drag reduction potential of this vehicle class.

- What design requirements are Mach number similar?

- What performance requirements are Mach number sensitive?

• Aerodynamic technologies for S&C improvements must be pursued.

- Control effector design opportunities exist!

- Stability management concepts must be explored!

• Innovation and high risk work must have a home in CA.

- Boundary layer management for performance and S&C improvements!

- Base drag management for performance improvements!

- Fuselage upwash management for performance and S&C improvements!

- Vehicle volume maximization for performance improvements!

The CA element has created for itself a number of significant technical challenges that require innovative solutions and teaming to be successful. However, before progress can be made there is a need to develop a consistent set of criteria and an understanding of the opportunities available to the CA team. Listed above are several issues which should be resolved and opportunities which must be pursued.

First NASA/Industry HSR Configuration Aerodynamics Workshop _-_A Sp_d _mardi Technical Performance & Technology Readiness Level Technology Technology Final Technology Assessment c_p, Muld-p, Con,s>ration Con,s>ration Design NecsilsiDiverter Oate (1196_,_ _-_t Technology Readiness

I ' jA,, A

Level Fief H Pod Cruise Non-linear Tech Concept Tech Cruise Pt. Acre A.sese. Acre Per/ t Wing Design Verified Method I Valid. 1g.5 _H 14.5 TCA lS Key _ 14.0 n._ H I O Subsonic v 13.7 TCA • Supersonic ICurrent I Status ° Projections Most likely I • Full scale values I • Updated per Tech Audit for * * Includes Technology UD Ref H planform (0/95) 10 • TCAperTl(11/95") I ga_nstodato 9.1 TCA (.og2) 9)8.63 TCA (0.92) 8.7 Ref H 8.5 RofH optimized design I Note." Aero • • 8.1 RofH lincar dcatgn 8.2 8.1 met this goal (I_)S) (_S) I I w;o..4 s i i i i I t I I I t I I 92 93 94 95 96 97 98 99 O0 01 Fiscal Year First NASAJIndustry HSR Configuration Aerodynamics Workshop TECHNOLOGY CONCEPT CRUISE_ IJDmax_PROJECTI ONS 10.0 MACH = 2.4 UpperBOund????

9.5 Z_TOW : -a_,oo_b 1998 Polentlal ,_../D = 11.4% I NomUnear PO.hll 9.0 i DeCgn [_L/D =4.3% I .Wing Camber/Twit Z_VITOW = -33,0001b I I °Wing TM 1995 StatUs "• Wing Bluntness LJD e.s • sows_oe • BodyArea Non-LinearPoint ii • BodyCamber Design • Aft Bodyrral_ _LREFERENCE_ ° TrimDrag • Wing Camber/Tw_ • LndGear Int.

I Un_rDe_gn ° WingThickness • Nacelle Int.

8.0 ' Wlr_ Bluntness • inlet Flow I 1970 Technology ,, BodyCamber Constraints oNacelle Effects

I, Wing _mbe;'[l"wis!

• Complete Design ' LI_ Design I* Body._a Constraints Constraints [* Nacelle tnteg • VIscouSOeeign • Inviscid/Vtsoou$ • Ir_roved Design 7.5 Design • WT Va_,datlon - WT Validation Process III 7.0