20 Foot Vertical Spin Tunnel...20 FOOT VERTICAL SPIN TUNNEL ENHANCEMENTS STUDY I. Introduction In October 1996, the Facility Systems Engineering Division (FSEO) initiated an effort

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National Aeronautics and Space AdministrationLangley Research Center

Hampton, Virginia

Final Report

20 Foot Vertical Spin Tunnel

Planning Team

Facility Enhancements and Future Research Needs

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Table of Contents

I. Introduction 1

II. Team Members 1

III. Approach to Brainstorming 2

IV. Schedule of Meetings 2

V. Background 2

VI. The Need for a Vertical Flow Tunnel 3

VII. Langley's Vertical Spin Tunnel Compared to Others 4

VIII. Guiding Principles for the Organization of Ideas 5

IX. Brainstorming Results 6

X. Implementation, Cost and Schedule 11

XI. Findings 12

XII. Recommendations 13

APPENDIX 1 14

APPENDIX 2 15

20 FOOT VERTICAL SPIN TUNNEL ENHANCEMENTS STUDY

I. Introduction

In October 1996, the Facility Systems Engineering Division (FSEO) initiated aneffort to conduct a series of brainstorming sessions to study the future needs ofthe 20 Foot Vertical Spin Tunnel. The purpose of the effort was to establish avision for the future of this facility and look at its short term and long term needs.The brainstorming would be conducted by a joint team from FSED and the FlightDynamics and Controls Division (FOCO).

Thus, a mUlti-disciplinary planning team was assembled to collect and documentideas relating to enhancements or modifications to the facility to (a) increaseproductivity, (b) remedy current deficiencies or roadblocks, (c) provideenhancements to current capabilities, and (d) provide new capabilities toenhance Langley's position of leadership in aircraft flight dynamics research andspin research.

II. Team Members

Eight people from Langley's Internal Operations Group (lOG) and the Researchand Technology Group (RTG) contributed their efforts to the team, as follows:

Facility Systems Engineering Division (FSED)Carlos S. Perez-Ramos, Team LeaderDavid A. Wineman, Facility Systems EngineerLuis E. Gutierrez, Mechanical EngineerRufus C. Sykes, Automated Controls EngineerRobert J. Wallis, Civil and Structural Engineer

Flight Dynamics and Control Division (FDCD)Raymond O. Whipple, Research EngineerC. Michael Fremaux, Research Engineer

Facilities Program Development Office (FPDO)P. M. Jackson, Jr., Minor CoF Program ManagerRichard T. Layman, Real Estate Officer

Given the scope of the brainstorming sessions, the group above included anideal number of people because it provided sufficient and varied levels ofexpertise and experience in the engineering and research disciplines, and inLaRC corporate knowledge, while at the same time allowing the sessions to beinformal and dynamic.

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III. Approach to Brainstorming

The approach used to identify opportunities for improvement, as well as anyfuture research needs included the following steps

• Understanding the current facility operations and research capabilities

• Identifying roadblocks to productivity

• Identifying future research needs

• Identifying current limitations which could impede implementation of futureresearch needs

• Funding and schedule constraints

• Collecting ideas for improvements to the facility

• Grouping of ideas, taking into account any global assumptions and/orguiding principles

• Prioritizing of ideas within the groups

• Developing top level implementation concepts and cost estimates

At the onset, it was attempted to center the discussions framed within theboundaries and rules set by the Construction of Facilities (CoF) program. Thepurpose, in a sense, was to steer the discussion and maintain the group effortfocused within some known frame of reference. This approach was found to beineffective because the team members had a tendency to discard ideas basedon a preconceived notion of the cost of implementing the idea.

IV. Schedule of Meetings

The schedule of meetings is presented in the Gantt chart included in Appendix 1.A total of five 2-hour meetings over a period of six weeks was required to collect,compile, and document the information contained herein. Meeting notes weredistributed to the team members prior to all sessions to serve as an aid in thecontinuation of the (;iiscussions. A two hour limit per meeting was selected tomake this activity non intrusive in the team member's schedules.

v. Background

The 20 Foot Vertical Spin Tunnel is an unique facility at the NASA LangleyResearch Center. Its primary mission is to conduct research to characterize thespin behavior of aircraft by testing free-spinning, dynamically scaled models.

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Spin research is defined as the end portion of the flight dynamics researchspectrum, where the air stream is normal to the aircraft's axis and theaerodynamic and gravitational forces are in equilibrium. Spin recoverycharacteristics of aircraft are studied to determine how control surfaces must beused to get an aircraft out of the spin mode as quickly as possible and return it toa stable flight regimen. Video cameras and recording equipment are used torecord the spinning and recovery characteristics during free spin tests.

The Vertical Spin Tunnel is also used in the evaluation of forces and momentsacting on models by means of a rotating model support system, the RotaryBalance System (RBS). This system suspends the model in the air stream andpermits angles of attack from -900 to +900

, as well as sideslip angles from -450 to+450

, while maintaining the position of the center of gravity of the model. Forceand moment data from these tests is collected and recorded through the use of adigital computer data acquisition system.

The Langley Vertical Spin Tunnel was built in 1940. It has a test section 20 feetin diameter and 25 feet long. The tunnel design includes a vertical annularreturn with continuous air flow and a closed th roat. Maximum accelerationcapability is 15 feet per second per second. The sustained air stream velocityrange is 0 to 80 feet per second, obtained by use of its 400 HP main drive motorand a three-blade, fixed pitch, fan blade system.

Langley's Spin Tunnel's critical importance to the U.S. Department of Defense isillustrated by the fact that the Spin Tunnel is the only test facility which isreferenced as a requirement in military testing standards, such as MIL-D-8708,"General Specification for Aircraft Weapon Systems, Demonstratiori', and MILSTD-1797A, UFlying Qualities of Piloted Aircraft'.

VI. The Need for a Vertical Flow Tunnel

The majority of aeronautics research facilities are horizontal flow tunnels, wherethe air flow stream is normal to the force of gravity. This arrangement is usefulfor simUlating most of the conditions experienced by an aircraft during normalflight.

Other flight research needs require that tests be conducted in a facility where theair flow is parallel to the force of graVity. This requirement can only be met by avertical flow tunnel. In this type of facility, an aircraft model can float in midairstream when the aerodynamic drag forces are in balance with the downwardpull of gravity, thus providing a perfect test medium for aircraft spin research,capsule reentry research, helicopter rotor research, and parachute testing, tomention a few examples.

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A question that was posed to the team was "Can the vertical flow facility atWright-Patterson AFB take over the entire spin research program in the UnitedStates?". The capabilities of this facility appear to match or even exceed insome areas the capabilities of Langley's tunnel. The answer is "yes" if youconsider spin research as an isolated unit or requirement. But, if spin research isviewed as an integral part of flight dynamics research , then it follows thatLangley Research Center is uniquely positioned to provide the full spectrum ofaircraft flight research, which includes spin testing, with its unique combination ofresearch facilities and experienced research staff. It is therefore very importantfor Langley to ensure that its spin research facility keeps up with the times. TheWright-Patterson tunnel is a 53 year old facility and thus is prone to experiencesimilar difficulties if enhancements or modifications were to be implemented. Inaddition, high turnover rates among the facility's staff prevents Wright Pattersonfrom fostering the necessary accumulation of corporate knowledge to ensurecontinuity of their research programs.

VII. Langley's Vertical Spin Tunnel Compared to Others

Included in Appendix 2 are data sheets from other vertical flow tunnels which arecomparable to Langley's Spin Tunnel in capability. The data sheet from thefacility at Wright-Patterson AFB and the ONERA facility in France werereproduced from the Aeronautical Facilities Catalogue, Volume 1, "WindTunnels', NASA RP-1132, January 1985. The data sheet from the TsAGIVertical Subsonic Wind Tunnel in Russia was obtained from the book"RussianAeronautical Test Facilities' by the ANSER Center for International AerospaceCooperation, 1994. Not included is a data sheet for the Bihrle Applied Researchfacility in Germany. This facility has been used by the United States Departmentof Defense (000) to conduct rotary balance tests due to unavailability of theLangley facility.

At a glance, several key differences can be seen between Langley's Spin Tunneland the others, as follows:

• The Wright-Patterson tunnel, the ONERA tunnel, and the TsAGI tunneluse an "apen throat" design. Langley's facility uses a closed throatdesign. The open throat reduces the boundary effects that can bedeleterious to rotary balance tests. This design allows easy access tothe test section and lends itself to rapid reconfiguration of the facility.

• Langley's tunnel has the largest test section of the four facilitiesstudied, yet its maximum air speed is the lowest at about 80 feet persecond. This speed limitation affects the maximum weight of free spinmodels that can be tested at Langley. With the renewed use of the

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20 FOOT VERnCAL SPIN TUNNEL ENHANCEMENTS STUDY

Spin Tunnel for reentry capsule research, the air speed limitation couldseriously impair our capability to conduct this type of research.

• The Wright-Patterson and French facilities appear to have beendesigned for ease of access to the critical maintenance areas, i.e., thefan drive system and fan blades. Maintenance at the Langley facility istime consuming and expensive because a means of access to thecritical maintenance areas was not built into its design. This limitationwill be more evident when the variable pitch fan system is installed dueto the increased number of moving parts which could require service,thus potentially increasing facility downtime.

Some of the ideas for enhancements to the Langley Spin Tunnel documented inthe next section are a reflection of the ideas gathered from learning about theother spin research facilities.

VIII. Guiding Principles for the Organization of Ideas

A number of assumptions were made by the team members to guide theprioritization and organization of the ideas obtained during the brainstormingsessions. The approach was to gather ideas that could be implemented asmodifications to the existing Vertical Spin Tunnel as opposed to those ideaswhich could only be efficiently implemented in a new vertical flow tunnel. Thediscriminator used for this division of ideas was whether extensive modificationsto the tunnel support structure would be required or not.

Assumption #1

Modifications to the facility that would impose major additional structuralloads on the existing tunnel steel frame and concrete foundation aredeemed cost prohibitive for implementation in the existing tunnel. Thisassumption is based on the fact that (a) the tunnel structure was built in1940 and its load bearing capability is unknown (b) attempting to test oranalyze the tunnel structure's present condition would require diverseefforts and could produce uncertain results, (c) any major modification tothe structure would require the complete removal and replacement of theexisting asbestos siding, which could make prohibitive the cost of anysuch modification.

Assumption #2

Any modification to the facility which requires an extended shutdown ofresearch operations (> 6 months) is deemed undesirable in the existingtunnel. The Vertical Spin Tunnel has a backlog of research which must be

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completed without major interruptions in order to maintain the satisfactionof Langley's external customers.

Assumption #3

Any idea not suitable for implementation in the current facility willautomatically be assumed to be inherently included in the design of a newvertical flow tunnel.

IX. Brainstorming Results

The results of the brainstorming sessions is presented below through a listing ofthe identified "Roadblocks to Productivity" and "Future Research Needs",followed by a number of ideas that address these and other important issues,grouped in two major categories, namely, "Ideas for Improvements to the ExistingFacility" and "Ideas that Indicate the Need for a New Facility". All ideas arepresented in order of priority.

Roadblocks to Productivity

1. Fan blade inservice inspections and fan blade motor maintenance operationsrequire extended facility shutdowns. Scaffolding must be erected andsubsequent~y disassembled to obtain access to the fan system.

2. Air flow unsteadiness frequently produces early and unpredictable testtermination.

3. Damage to test models occurs on impact with test section walls.

4. Unreliable electrical power causes fan speed variations, which can produceearly test termination, and also disturbs the facility's computer systems.

5. The Rotary Balance System is not fully retractable, thus not allowing settingup a test while the facility is running free spin tests.

6. The drawbridge has to be assembled and disassembled every time it is usedto gain access to the center of the test section.

Future Research Needs

1. Forced oscillation capability for the Rotary Balance System.

2. Increased air speed to allow testing of larger or heavier models.

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3. High resolution video system with freeze frame capability for testdocumentation.

4. Fully retractable, multi-degree-of-freedom model sting with forced oscillationcapability.

Ideas for Improvements to the Existing Facility

1. Perform engineering studies to (a) survey the air flow profile and suggestmodifications to improve flow quality, (b) assess the load bearing capabilityof the existing structure, and (c) assess the health of the existing power grid.

• A 15% scale model of the tunnel test section, diffuser, and entrancecone exists which could assist in flow quality studies.

• In order to assess the true viability of any modification to the facility,it is imperative to understand the limitations imposed by the existingstructure. The tunnel structure is a welded and riveted structuredating back to the year 1940.

• Some of the existing facility wiring is old and does not comply withcurrent electrical codes.

2. Design and build a new set of fan blades to improve their long termstructural integrity.

• The new variable pitch fan blades were designed as clam-shellstructures. Even though these blades passed the required testingduring fabrication, concerns remain about their long term·structuralintegrity.

• As a minimum, a spare set of identical blades is needed to minimizefacility downtime in case of premature blade failure.

3. Add forced oscillation capability to the Rotary Balance System.

• This new capability could be added to the existing RBS at minimalcost.

• Additional analysis work is required to ensure the RBS is notoverloaded.

4. Modernize the facility's video systems.

• A new, high speed, off-the shelf, high resolution S-VHS video systemis needed to replace the existing low resolution video documentationsystem for spin tests. This system would offer high quality freeze

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frame and frame by frame viewing options.

• The existing high speed video tracking system for data acquisitionneeds to be upgraded to contemporary technology.

5. Provide a new model impact-protection system.

• Damage to the model occurs when it impacts the walls of the testsection due to the excessive stiffness of the padding.

6. Provide clean power for the entire facility.

• Clean power is currently provided through a number of smallisolation transformers scattered through three buildings.

7. Add the capability to have a standard, removable model sting.

• This new capability could enhance the scope of research activities atthe tunnel.

• The sting would be bolted to the existing tunnel structure to allow itscomplete removal from the air stream.

• A fUlly automatic and retractable system may not be feasible in thecurrent facility due to structural load limitations.

8. Rewire the entire facility and replace the flood light system.

• Some of the existing wiring is not in compliance with today'selectrical codes. Voltage drops are common causing the fan motorto drop speed and the data acquisition system computers tomalfunction.

• The existing floodlight system was designed for use with high speedfilm, not video. In addition, bulbs require frequent replacement,perhaps associated with the aging electrical grid.

9. Make the draw bridge integral with the facility.

• The draw bridge is a manually removable platform to gain access tothe centerline of the tunnel. Integrating it with the facility structureand making it fully retractable would enhance the productivity ofrotary balance tests, parachute testing and other specialized testing.

10. Provide a facility process monitoring system.

• This system would passively gather data from the various tunnelsubsystems to assess facility health.

• The system could be useful for preventive maintenance and facilitytroubleshooting.

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10. Replace the utility piping servicing the tunnel.

• The steam piping in the tunnel leaks frequently requiring servicecalls. It is also suspected that the piping is insulated with asbestos.

• The current project to install new steam boilers in Building 646 doesnot include replacing the steam distribution piping in its scope.

12. Replace the existing asbestos siding.

• The purpose of this modification is to comply with environmentalrequirements.

• The existing transite siding is not friable, unless it is torn orpunctured. Most modifications listed herein would requirepenetration or partial removal of the siding, therefore requiringspecial handling and increasing the cost of the work.

13. Provide modifications for ADA compliance.

• The tunnel already has a personnel elevator but lacks personnel liftsand restroom facilities for people with disabilities.

Ideas that Indicate the Need for a New Facility

1. Replace fan motor with a more powerful unit to increase air speed.

• A study conducted in the 1980's deemed this modification notfeasible with the existing structure. Nevertheless, low air speed isthe tunnel's greatest limitation for free spin testing.

2. Provide means for rapid facility reconfiguration and calibration.

• Rotary balance tests require a flat velocity profile, but spin testsrequire a "bowl shaped" velocity profile. A system to allow the facilityto rapidiy change from one configuration to another and recalibratewould enhance overall productivity.

3. Build a penthouse for access to fan motor and fan blades.

• Due to the unknown load bearing capabilities of the existingstructure and foundation, this option was deemed impractical toimplement now. This feature becomes more of a necessity with theuse of the variable pitch fan system because it will require morefrequent maintenance and inspection than the fixed pitch system. In

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the current facility, this maintenance task will be costly and timeconsuming.

4. Provide an integrated tunnel control system and process monitor system.

• The use of a modem digital control system and artificial intelligencesystems could simplify operations.

• This idea was deemed impractical in the existing tunnel due to thelack of real estate in the existing control room.

5. Provide a system to completely retract the Rotary Balance System from theair stream.

• The existing RBS is retractable but it stays inside the test section.The concept is to make this subsystem fully retractable, thusallowing the setup of an RBS mounted model while free spinresearch is ongoing.

• Modifications to the tunnel support structure could be required toimplement this idea.

6. Add the capability to have a fully retractable, multiaxis model sting withforced oscillation capability.

• This new capability would serve to complement the capabilitiesenvisioned for the 14 x 22 Foot Tunnel.

• Although the 14 x 22 Foot Tunnel has a wider range of air streamvelocities in which forced oscillation tests can be conducted, the costof operating that facility is much greater than the Spin Tunnel. Also,due to the 14 x 22 Foot Tunnel's busy schedule, its availability toconduct these tests is questionable. Thus it would be more efficientto conduct some of the low speed forced oscillation tests at the SpinTunnel.

7. Redesign the entire tunnel circuit.

• Existing design consists of a vertical annular return.• New concepts to be considered include the use of a single return-leg

design, open-throat test section, fully retractable andinterchangeable test sections, and rapid facility calibration systems.

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20 FOOT VERnCAL SPIN TUNNEL ENHANCEMENTS STUDY

x. Implementation, Cost and Schedule

Modifications to the existing tunnel

Due to the Spin Tunnel's busy schedule, it is preferable to proceed with animplementation plan that reduces the amount of facility downtime. Some ofthe ideas listed could be implemented by FOCO with minor intervention fromFSEO.

a) Engineering studies

b) New fan blade set, design and build

c) Forced oscillation capability for RSS

d) Video system upgrade

e) Model impact protection system

f) Multiaxis sting

g) Rewire entire facility

h) Facility process monitor

i) Utility piping repair

j) Draw bridge

k) Asbestos replacement

I) ADA compliance

Total

New Vertical Flow Tunnel

$ 250 K, 6 mo.

$ 200 K, 12 mo.

$100 K, 4 mo.

$ 50 K, 3 mo.

$100 K, 9 mo.

$ 500 K, 12 mo.

$ 275 K, 12 mo.

$ 50 K, 9 mo.

$ 150 K, 12 mo.

$ 50 K, 9 mo.

$ 700 K, 12 mo.

§ 120 K, 9 mo.

$2,295 K

$10-$20M

A new and enhanced Vertical Flow Tunnel could be built in the vicinity of the14 x 22 Foot Tunnel. This new tunnel could be designed to be able toconduct some of the research that used to be done at the Full Scale Tunnel.

It should be noted that the implementation of items (a) through (I) above donot produce a facility with the same capabilities or the same level ofproductivity as a new vertical tunnel would have. Thus, it is not possible tocompare the bottom line figures to decide which approach is more desirable.The final decision must weigh factors such as the importance of taking aproactive stance in preparing the Vertical Spin Tunnel to meet the researchneeds of the future, and the importance of expanding the Spin Tunnel's

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capabilities for the purpose of offloading some of the low speed researchbeing planned for the 14 x 22 Foot Tunnel, which operates at much highercost per run.

The design of a new facility of this magnitude could take 9 to 12 months, withconstruction lasting 18 to 24 months, and facility activation and calibrationanother 12 months. Construction of a new vertical flow tunnel on the WestArea of Langley Research Center would allow the existing facility to operateduring the entire process, thus eliminating facility shutdown requirementscompletely, and would also eliminate the real estate limitations of the currentsite at the Langley Air Force Base.

XI. Findings

1. The 20 Foot Vertical Spin Tunnel is a vital facility for NASA's AeronauticsEnterprise. It plays an important role in making Langley Research Center aworld leader in aircraft flight dynamics research and spin research. Failure tosupport the needs of this facility could result in a loss of that position ofleadership and could force the DoD to shift their research funding to the facility atWright-Patterson AFB or to facilities overseas. Only NASA-Langley can offer theU. S. Department of Defense an integrated testing infrastructure with the supportof an experienced flight dynamics research staff to meet their fighter aircrafttesting needs while ensuring that national security interests are properlysafeguarded.

2. The Langley Vertical Spin Tunnel is a 56 year old facility. Limitations exist inthe current facility configuration that have already had an impact on research. Inaddition, some needed modifications or enhancements could be cost prohibitiveto implement due to the age of the facility.

3. Future research requirements have been identified that cannot be fully met byLangley's Spin Tunnel, for example, capsule reentry research and spin researchfor large transport aircraft (such as the HSCT).

4. New, desirable Gapabilities have been identified which indicate the need for anew and enhanced Vertical Flow Tunnel at LaRC to complement and augmentour overall flight dynamics research. These include higher air stream speed,forced oscillation testing capability, multi-degree-of-freedom model supports, andfully retractable and interchangeable test sections to enhance productiVity. In theabsence of all budget and scheduling constraints, it is possible to conceiveadding some of these capabilities to the existing spin tunnel. The reality is thatthe aging condition of the facility's support structure, its geographical location ina very congested area of Langley Air Force Base, and the research backlogpresent serious impediments to what can be effectively accomplished.

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XII. Recommendations

1. It is recommended that FOCO and FSEO establish a plan for implementationof the most desirable ideas for modifications to the existing facility aspresented in this document.

2. It is recommended that a feasibility and requirements identification effort beinitiated immedia.tely to determine whether there is sufficient support at theCenter and Agency level for the construction of a new and enhanced VerticalFlow Tunnel at Langley Research Center.

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Planning for Enhancements to 20 Foot Vertical Spin Tunnel

10 Task Name Duration

1 Master Schedufe 66d

2 Session 1 - Kickoff Od

3 5ession 2 - FadUly Toor Od

4 Minutes DiStributed for Review 2d

5 session 3 • Slonnbraining Od

6 session 4 • Brainstorming and Prioritization oct

7 Develop First Draft of Proposal 3d

8 Distribute First Draft for Comments 3d

9 session 5 • Feedbakck 00 First Draft Cd

10 Develop FIIlaI DoaJment 40d

By: Cartos S. Perez-Ramos

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SUBSONIC WIND TUNNELSCOMPARABLE

NASA-Langley FACILITIES

Research TEST SECTION SIZE: SPEED RANGE: 0.08 Group G

Center 20-ft dia x 25 heigh t (Mach No.) (90 ft/see)

DATE BUilT/UPGRADED: TEMP. RANGE:

1940/1984 Ambient

REPLACEMENT COST: REYNOLDS NO:20-Ft

,$1.4M (Per ft X 10-8) 0-0.62 ~

Vertical OPERATIONAL STATUS: DYNAMIC PRES:Spin Tunnel (lb/ft2 ) 0-10

2.5 shifts per day (backlog) STAGNATION PRES:(psia) Atmospheric

Acceleration capability: 15-ft per sec2 Test medium: Air

Deceleration capability: 25-ft per sec2

Vertical annular return, continuous flow, closed throat

TESTING CAPABILITIES: The spin tunnel is used to investigate spin characteristics of airplanes by testing free-spinning dynamically scaledmodels. Spin recovery characteristics are studied by remotely actuating the aerodynamic controls of models to predetermine posi tions. Foree

and moment testing is performed using a gooseneck rotary arm model support, which permits angles of attack and slideslip from OC to 360- .

r.1otion picture records are used to record the spinning and recovery characteristics in the spin tunnel tests. Force and moment data from the

rotary balance tests are recorded in coefficient form and stored on flexible disk. This facility is powered by a 1300-hp main drive.

DATA ACQUISITION: HP 9845 computer on the rotary balance.

CURRENT PROGRAMS: Free-spinning tests on military trainer and fighter aircraft. Rotary balance tests on general aviation as well as on a

figh ter aircraft.

PLANNED IMPROVEMENTS: Fiscal Year 1984 - Rehabilitation of 20-ft Vertical Spin Tunnel.

LOCAL INFORMATION CONTACT: James S. Bowman, Jr., Flight Dynamics Branch, (804) 856-2521.

112

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ONERAFACILITIES

II.!F.'LI LLE. TEST SECTION SIZE: SPEED RANGE: 0.12France 4-m diameter (Mach No.) (40 m/sec max) Group G

DATE BUILT/UPGRADED: TEMP. RANGE:Atmospheric1966

-REPLACEMENT COST: . REYNOLDS NO:

SV4(Per m X 1(t6) Up to 2.7

Spin Tunnel OPERATIONAL STATUS: DYNAMIC PRES:(kN/m2 ) Up to 1.0

Active STAGNATION PRES:(bars) 1

Continuous flow, annular return circuit, open-jet test sectionElectric motor: 460 kW

TESTING CAPABILITIES: The spin tunnel is used to investigate spin characteristics of airplane by testing free spinning of dynamically scal~d

models (Froude criteria). The test section can be equipped with a new rotary balance rig for studying the dynamic derivatives on the same models.as \vell as the steady characteristics, up to very large angles-or-attack/sideslip combinations.

DATA ACQU ISITION: Recording of onboard instrumentation (accelerometers ...) and control surfaces position; correlation wi th fligh t measure·ments.

CURRENT PROGRAMS:

PLANNED IMPROVEMENTS:

LOCAL INFORfvlATION CONTACT: Marc Pianka, Director, ONERA/IMF LUle, 5 Bd Paul Painleve, 59000 LILLE, France, (20) 53.61.32.


FACILITIESWright TEST SECTION SIZE: SPEED RANGE: 0-0.13Aeronautical

12 x 15 £t (Mach No.) (0 - 150 ft/sec) Group GLabora taries I

Wright- DATE BUILT/UPGRADED: TEMP. RANGE:

Patterson AFB 1943 Ambient

REPLACEMENT COST: $ REYNOLDS NO:0-0.912.25M (Per It X 10-6)

Vertical ' .

OPERATIONAL STATUS: DYNAMIC PRES:Wind Tunnel (lb/ft2 ) 0-26

1 shift per day.STAGNATION PRES:(psia) Atmospheric

Vertical, closed, circuit, annular return, open jet tunnel

TESTING CAPABILITIES: This closed-circuit, vertical wind tunnel allows free-float testing of aircraft, store, and parachute models. Varioussupport systems are available: truss model support, cable mounts, and strut for load cells and stings.

DATA ACQU ISITION: Minicomputer with 30 channels for input data. High-speed motion picture and still-photographic coverage available.Videotape recording equipment available.

CURRENT PROGRAMS: This unique facility is currently used to determine aerodynamic forces and moments of aircraft models, drag and stabilitycharacteristics of parachutes, and the spin and recovery characteristics of flight vehicles. It is also used for free-fall training classes.

PLANNED IMPROVEMENTS: Installation of additional antiswirl vanes, a symmetrical cone at the center, and turbulence reduction screens V/ill

reduce the overall turbulence intensities and provide a more uniform flow at the test section (May 1984 - approximate cost $1000).

LOCAL INFORMATION CONTACT: 1st Lt. Wendell M. Baker, AFWAL/FIMM, (513) 255-5042.

114

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Vertical Subsonic Wind Tunnnel T-IOS (T-IOS)

Primary Technical Parameters:Flow Velocity:Flow Direction:Reynolds Number:Total Pressure:Dynamic Pressure:Stagnation Temperature:

Run Duration:

5 - 35 m/secUpwards3.3 x 106 m-1

Atmospheric0.74 kPa295 K (summer)300 K (winter)Continuous

Type:Test Section Dimensions:

Circular Nozzle Diameter:Test Section Length (Height):

State of Operations:Date of Modifications:

Continuous Flow

4.5 m7.56 m

Active1957, 1978, 1988

General Description: T-105 is a continuous-operation, vertical, closed-layout facility with anopen test section designed to investigate the spinning properties of dynamically similar airplanemodels in free flight conditions.

Capabilities: The wind tunnel is equipped with devices for testing airplane models at a widerange of angles of attack and side slip angles (up to 360°), helicopters of various configurations,rotors, steering rotors, airships, parachute systems, and industrial objects. Airflow is driven bya fan that consumes 450 kW of power. The models are remotely controlled by an informationmeasurement [computer] control system, which also acquires and processes the data. T-I05 isdesigned to measure:

· X, Y, Z, Mx' My, and Mz for airplane, helicopter, and rotor modelspressure distributions across airplane, helicopter, and rotor blade models

· deflection angles and strains of rotor blade models

and to determine:

· control surface positions· downwash angles and induced velocities.

Unique Characteristics: The structural features of the test section enable investigations ofairplane spin and aerodynamic characteristics of rotating aircraft models and helicopter rotors...

Practical Use: This facility was used to perform spin tests of many military and civil airplanemodels, to determine aerodynamic characteristics of fighters at high angles of attack, and toinvestigate rotor-helicopter body configuration interactions.

2-23 ANSER

Documents

20 Foot Vertical Spin Tunnel...20 FOOT VERTICAL SPIN TUNNEL ENHANCEMENTS STUDY I. Introduction In October 1996, the Facility Systems Engineering Division (FSEO) initiated an effort