8-Foot Transonic Pressure Tunnel
|Center:||Langley Research Center|
|Historic Eligibility:||National Register Eligible|
|Important Tests:||Shuttle Thermal Protection, supercritical airfoil, winglets, area-rule testing, laminar flow|
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In the years after World War II, Langley physicist Ray H. Wright observed that the interference from wind tunnel walls could be minimized by placing slots in the test section throat, a concept that came to be known as "slotted throat" or "slotted wall tunnel" design. Experiments with this design revealed that it could allow for transonic speeds (up to and beyond the speed of sound, or Mach 1, approximately 761 mph at sea level). Although Langley's retrofitted 8-Foot High Speed Tunnel and 16-Foot High Speed Tunnel were conducting transonic testing by the end of 1950, they experienced a number of problems, including excessive turbulence, and high humidity and fog caused by drawing outside air into the main airstream for cooling. It soon became apparent that a completely new tunnel was necessary to fully exploit the usefulness of the new slotted throat design.
Langley's 8-Foot Transonic Pressure Tunnel (TPT) was completed in 1953 (on the former site of the Propeller Research Tunnel). The tunnel was capable of operating at pressures between 0.1 and 2.0 atmospheres, and had sophisticated air temperature and humidity controls. The air speed in the test section could be continuously varied up to Mach 1.2, depending on the size of the testing model, while the addition of a new plenum section in 1958 increased the speed potential to Mach 1.3.
A study was made around 1960 to determine whether the 8-Foot TPT compressors could be utilized for powering a high Mach number facility. The result was the construction of a 2-Foot Hypersonic Facility on the second floor of the 8-Foot TPT. An ejector system obtained Mach numbers from 3 to 7, and the compressors supplied air at very low test-section densities. Simulation of the low densities was important for configurations designed for high altitudes where there was rapid boundary layer growth. (See report: Description of a 2-Foot Hypersonic Facility at the Langley Research Center).
Many area-rule configurations, although originally developed in the 8-Foot High Speed Tunnel, were tested in the 8-Foot TPT. This is the principle that — in practical terms — prompted the use of a compressed, or “wasp-waisted,” fuselage design for supersonic jet fighters, allowing them to break what was popularly known as the “sound barrier.”
In the 1960s, the 8-Foot TPT was instrumental in the development of the revolutionary new supercritical airfoil. As a supersonic aircraft reaches the speed of sound, there is a point at which the air flowing over the wings reaches supersonic speeds while the plane itself is moving slower, causing a significant drag effect. Langley engineer Richard Whitcomb achieved a major breakthrough while researching this problem, developing a new airfoil (or wing cross-section) shape that would allow the wing to reach a higher speed before the airflow over it reached the speed of sound. Whitcomb and his research team extensively tested this new design-what he termed the "supercritical airfoil"-in the 8-Foot TPT. By the mid-1970s, supercritical wings were being used in the design of a wide variety of commercial and military aircraft, greatly increasing their speed, range, fuel efficiency, takeoff and landing performance, and maneuverability.
In the 1970s when fuel prices began spiraling upwards, the aircraft industry looked at ways to improve efficiency. The concept of winglets originated in the late 1800s in Britain, but remained on the drawing board until the 70s when Richard Whitcomb refined the concept and began testing his ideas. Winglets are vertical extensions on aircraft wing tips which proved to reduce aerodynamic drag associated with vortices that develop on the ends of aircraft wings. They continue to be used extensively throughout the aviation industry. Whitcomb's original work was conducted in the 8-Foot Transonic Pressure Tunnel.
In addition, this tunnel was used to investigate research concepts like laminar flow control. Many past and present aircraft and space craft were also tested in the 8 ft. TPT including Saturn/Apollo, Scout, Space Shuttle, C-141, C-5, YC-15 (C-17), B-1, F-8, F-14, F-111, F/A-18, the Supersonic Transport, DC-10, Cessna Citation, and the Gates Learjet.
Through the 1980s and 1990s, Langley engineers continued to use the 8-Foot TPT for testing, including evaluations of the space shuttle design, and experiments requiring subsonic and transonic capabilities. The following provides an outline of contributions to the Space Shuttle Program:
• From 1969 to 1972, during the earliest phases of the Space Shuttle Program (the Contractual Studies phase and the Concept Definition phase), numerous tests were conducted of various potential Shuttle-type designs.
• In 1973, wind tunnel tests of the NASA/ Rockwell Orbiter model were conducted to obtain longitudinal stability and control data.
• In 1973, experimental longitudinal and lateral-directional stability characteristics of a Langley-designed Space Shuttle Orbiter were tested.
• In 1974, aerodynamic force and moment tests were conducted on a Space Shuttle vehicle configuration.
• In 1974, an experimental test program was conducted to measure the dynamic stability derivatives of a modified Shuttle Orbiter design.
• In 1974, aerodynamic tests were conducted on a Space Shuttle Orbiter model.
• In 1975, subsonic and transonic forced oscillation tests were conducted on a model of a modified Space Shuttle Orbiter design.
• In 1977, a study of transonic beta hysteresis of a Space Shuttle Orbiter model was tested.
• In 1978, a drag reduction investigation on a Space Shuttle launch configuration was conducted.
• In 1981, a model of the Space Shuttle integrated vehicle was tested.
• In 1982, combined wind tunnel and vibration shaker tests were conducted on two Shuttle structural panels to determine the effects of combined loads on the thermal protection system (TPS).
• In 1982, the simulation of time varying ascent loads on arrays of Shuttle tiles was tested.
• In 1982, a model of the Rockwell Space Shuttle vehicle was tested.
• In 1986, tests were conducted to determine the effects of surface roughness on two Space Shuttle Orbiter models.
As with other early tunnels, computers were important to the research conducted at the 8-Foot TPT. In 1969, Helen Willey, supervisory mathematician, prepared A Manual for the Reduction of Data from the 8-Foot Transonic Pressure Tunnel. This served as the reference book for the women who were responsible for mathematical calculations.
Facing a surplus of tunnels in the post-Cold War era, NASA finally closed the facility in 1996. The facility was demolished in 2011. Click here to see the new homes for items that were salvaged. The small slotted-throat transonic test section that was used by John Stack at Langley as the pilot model for the 8-Foot TPT is on display at the Smithsonian's Udvar-Hazy Center. But John Anderson with the Smithsonian Institute, stressed that the major historical significance of the 8-Foot Transonic Pressure Tunnel was that it was Dick Whitcomb's Wind Tunnel.
Renovations and Modifications
Damage and Repairs
1957 Failure of Fan Blades Documents
1958 Failure of Turning Vane Cuff Document
[top] Models and Tests
1992 EET Model
[top] Group Photos and Social Events
1972 Researchers and Computers
[top] Photos Prior to Demolition
In 2008, we started taking extensive photos of this building in preparation for demolition. These photos capture the building and the condition it had fallen to.
[top] Demolition (2011)
NACA Emblem over TPT Door (transferred to Smithsonian)
The videos below are stored on the CRGIS YouTube Channel
2009: Part 1 - Introductions; Justification for 8' TPT (Audio Only)
2009: Part 2 - Working for Dr. Whitcomb; the Supercritical Wing Program (Audio Only)
2009: Part 3 - Other Supercritical Wing Applications; Winglet Program; Skepticism of TPT Technologies
2009: Part 4 - Transonic Studies of Engine, Nacelle, and Wing Intergration; Laminar Flow Control Tests
2009: Part 5 - Other Tunnels and Programs in Building 640; Closing Thoughts
2009: Part 6 - Post-Interview Odd Stories; Viewing of Old Area Rule Film
[top] General Reports
An Experimental Investigation of Boundary Layer Interference on Force and Moment Characteristics of Lifting Models in the Langley 16- and 8-Foot Transonic Tunnels. Charles F. Whitcomb and Robert S. Osborne. 1953. RM-L52L29.
Aviation Pioneer Richard T. Whitcomb. 2009. NASA People.
Description of a 2-Foot Hypersonic Facility. George M. Stokes. 1961. TN D-939.
The Development of Experimental Transonic Research Techniques. Axel T. Mattson. (Photos) and 1971 Correspondence by Working Group
Engineering Study on Wind-Tunnel Fan-Blade Materials. Edwin C. Kilgore. 1956.
Facility Description. Charles D. Harris and Cuyler W. Brooks, Jr. 1991.
Facility Resume. 1990.
From Engineering Science to Big Science. Pamela E. Mack, edit. 1998. SP-4219.
High Reynolds Number Wind Tunnels. draft note by Professire Hertzberg. 1969.
The High Speed Frontier. John V. Becker. 1980. SP-445.
Langley Research Solved Problem of Supersonic Transport's Design. The Times-Herald. 16 February 1967.
Main Drive Lubrication System . 1957.
Manual for Reduction of Data from the 8-Foot Transonic Pressure Tunnel. Helen H. Willey, Supervisory Mathematician. October 1969.
NASA Aviation Pioneer Dick Whitcomb Honored. Kathy Barnsdorff. 2007. NASA News.
Reynolds Number Requirements for Valid Testing at Transonic Speeds. William B. Ogoe and Donald D. Baals. 1971. draft.
Richard Whitcomb dies at 88; engineer's discoveries changed design of jets. T. Rees Shapiro. Chicago Tribune. 19 October 2009.
Simulation of Time-varying Ascent Loads on Arrays of Shuttle Times in a Large Transonic Tunnel. Percy J. Bobbitt, C.L.W. Edwards, and Richard W. Barnwell. 1982. TM-84529.
Transonic Free-Flight Model Testing at Large Scale. Clarence L. Gillis. 1971. presented at the AGARD Specialists' Meeting, Gottingen, Germany.
The 'Wasp-Waist' Plane The New York Times. 2 October 1955.
High Angle-of-Attack Work in Transonic Aerodynamics Branch. Briefing given at Wright-Petterson AFB, Ohio. 1989.
Wind Tunnel Research Techniques. Cuyler W. Brooks, Jr. 1989.
Airfoil Development. Dennis O. Allison. 1989.
Instrumentation. Cuyler W. Brooks, Jr. 1989.
Basic Results Slotted and Perforated LFC Models. Charles D. Harris. 1989.
HLFC Experiment. James C. Ferris. 1989.
Suction Control System. Cuyler W. Brooks, Jr. 1989.
Transonic CFD for Propulsion and Airframe Integration. James M. Luckring, Farhad Ghaffari, and Brent L. Bates. 1989.
LFC Airfoil Development. Dennis O. Allison. 1989.
Basic Results Slotted LFC Model. Cuyler W. Brooks, Jr. 1989.
Degree Delta Wing - Experiment and Code Validation Program Status. James M. Luckring. 1989.
Computations of Shocked Flows on Nonadapted Meshes Using Floating Shock Fitting. Peter M. Hartwich. 1989.
Simulation of Propulsion Effects. Neal T. Frink. 1989.
Transonic Aerodynamics Branch Overview. Lawrence E. Putnam. 1989.
Cooperative High-Alpha Programs Between Transonic Aerodynamics Branch and WRDC FIMM. William P. Henderson. 1989.
Airfoil & Alggrid - Two Specialized Utilities. Peter M. Hartwich. 1989.
Upwind Scheme for Solving the Euler Equations on Unstructured Tetrahedral Meshes. Neal T. Frink. 1990.
Advanced Subsonic Transport Technology High Reynolds No. Airfoil Wing Design. Lawrence E. Putnam. 1990.
HiSAIR Aero Team Status Report. Dick Campbell. 1990.
Aerodynamic Surface Design Methodology. Richard L. Campbell.
Applications of a Transonic Wing Design Method. Leigh A. Smith and Richard L. Campbell.
Transonic Applications of a Wing Design Method. Leigh Ann Smith.
Transonic CFD Applications. Edgar G. Waggoner.
Transonic Performance. Dick Campbell and Pam Phillips. not dated.
[top] Further Reading
Large-field high-brightness focusing schlieren system. Leonard M. Weinstein. AIAA Journal, Vol 31, No 7, July 1993. pp 1250-1255.
Basic of Focusing Schlieren Systems. Andrew Davidhazy. 1998.