16-Foot Transonic Tunnel
NASA Langley Research Center
| Mach number | 0.2 to 1.25 |
| Relative altitude, feet | 1000 to 28,000 |
| Reynolds number, per foot | 1 x 106 to 4 x 106 |
| Dynamic Pressure, psf | 65 to 920 |
| Stagnation Pressure | Atmospheric |
| Stagnation Temperature, degrees F | 40 to 180 |
High-Pressure Air and
Cooling Capability
High-pressure air lines, cooling water lines, and hydraulic lines are available in the tunnel strut head for connection to model components. Two individually controlled high-pressure air systems are available, each capable of providing up to 15 lb/sec mass flow at 1800 psi. Air is slightly heated to maintain a constant temperature at the model. A pair of multiple critical venturis is used to measure the mass flow rate of the air.
Propulsion model installed in 16-Ft TT.
Photographic (both 70 mm and digital) and video coverage of the test section are available from the sidewalls and ceiling. Video images of the model can be recorded with key tunnel parameters superimposed on the screen.
The 16-Ft TT can handle various internal 6-component strain-gage balances. Flowthrough balances are available for propulsion tests. The data acquisition system can acquire data for up to five balances on one model. Typical corrections to the balance are balance interactions, temperature effects, attitude tares, axes orientation, and pressure and momentum (flow) tares.
The electronically scanned pressure (ESP) system provides high accuracy measurement of steady-state model and facility pressures at rates up to 20,000 ports per sec. The system utilizes modules each containing 32, 48, or 64 individual transducers ranging from -2.5 to 100 psi. Up to 16 modules and 1024 pressure sensors may be used. On-line calibrations are performed as required to insure overall system errors not greater than ?0.25 percent of full scale. Up to 100 independent static pressure transducers and up to 40 dynamic pressure transducers can be connected to the model and facility.
Model attitude is computed with sensitive pitch accelerometers. Accelerometer packages, which can be mounted inside the model, are available to measure pitch only (one accelerometer) or pitch and roll (three accelerometers).
The standard data acquisition system consists of an analog-to-digital converter that is capable of acquiring 128 channels of analog data (up to 1000 Hz) and 40 channels of digital data and a UNIX computer. A 40-channel dynamic data acquisition system is also available. Final data are reduced on a separate UNIX workstation. For data analysis, the facility provides UNIX and Macintosh computers. Customer supplied computers can be networked to the data reduction system if desired. Secure data links are available for classified projects.
Two model buildup bays are provided at the facility for buildup of models. Also, a calibration area provides instrumentation and propulsion air systems for further calibrations that may be required to quantify deflection constants and propulsive tares.
Safety and Design Criteria
Langley?s LHB 1710.15 Wind Tunnel Model System Criteria is the guideline for model design and fabrication. Model installation and any exceptions to this document must have the approval of the 16-Ft TT Safety Head on a case-by-case basis to assure personnel and tunnel hardware are not exposed to risk.
