Langley Full Scale Tunnel
The Langley Full-Scale Tunnel (LFST), formerly the NASA 30x60 tunnel, is now operated by the College of Engineering and Technology, Old Dominion University, in collaboration with the Old Dominion University Research Foundation and a variety of support contractors. Bihrle is a principal support contractor to Old Dominion University (ODU), conducting aerodynamic research testing and analysis.

Description
The LFST facility is housed in a 434-ft long by 222-ft wide by 97-ft high building located on Langley Air Force Base in Hampton, VA. It covers approximately 2 1/2-acres and contains the wind tunnel, hangar area, office space and machine shop.

Tunnel Specifications
The tunnel test section is 30-ft. high, 60-ft. wide, with a quasi-elliptical cross-section, 56-ft. long. It is a closed-circuit, three-quarter open-jet, double-return, continuous flow design which operates at atmospheric pressure. The airflow from the dual fans mounted within the collector cone is split right and left into two equal streams, each doubling back between the test section and the building walls to the entrance cone, reuniting prior to the contraction section upstream of the test section.

The contraction is 75-ft. in length and in this distance the cross section changes from a rectangle of 72-ft. by 110-ft. to a 30-ft. by 60-ft. quasi-elliptical section. The area reduction in the contraction is slightly below 5:1. The shape of the section was chosen to give a constant acceleration to the air stream and to retain a 9-ft. length of nozzle for directing the flow.

The tunnel is powered by two 4,000-hp electric motors, each driving a four-blade 35.5-ft laminated wood propeller. The motors are mounted with rotor shafts centered within the exit cone passages. Rotational speed is varied by a solid-state control system. The motors and supporting structure are enclosed in fairings to minimize resistance to airflow. Motors are normally started at approximately 80-rpm and can be adjusted in increments of 1, 10, or 100, to a current maximum 210-rpm, around 80 mph in the test section. (The original design fan speed was 300 rpm giving a test section speed of approximately 120 mph. The tunnel was operated at this speed for 40 years and raising the tunnel speed to its original design value is a subject of future development). The control panel for monitoring the rpm is located in the control room, and includes a trim control to synchronize the two motors. For specialized purposes, the motor winding configuration can be switched to a "low speed" range, permitting steady rpms from around 20 to above 100.

The size and open-jet design make the tunnel ideally suited for a number of unique test capabilities, such as testing of large-scale aircraft or models and multi-vehicle formations.

The Ground Board and Turntable
The 1/4 inch smooth steel ground board is 42-feet 6-inches in width, 52-feet 9- inches in length and is elevated 21 feet 4 inches above the ground. Ample space is available under the ground board for running power cables and air supply lines. Four 120V receptacles are located on each side of the ground plane. A hydraulically driven turntable, 35 feet in diameter, can be rotated 360 degrees to create sideslip on the test article.

Full-Scale Model Support/Balance/Scale House
The full-scale model support, balance, and scale house are located directly below the ground board. It contains the six-component balance from which the readings are fed into the control room. The scales are capable of handling loads up to 20,000-lbs.

Control Room
Located adjacent to the scale house, the control room contains the controls for the drive motors, survey carriage, data systems, compressed air, and full-scale model support. Multiple video feeds allow the viewing of the ground board, test vehicle and fans.

Aircraft Test Capability
Large aircraft or aircraft models are mounted on the tunnel centerline by struts from the full-scale six-component balance beneath the test section floor. Struts can be extended 14-feet above the ground board with aerodynamic fairings installed to nearly eliminate tare-drag loads when using the external balance for measurements. Models weighing up to 15,000 lb can be accommodated.

Smaller models with internal force balances are attached to a hydraulically actuated model support that uses stings mounted on a centerline 'T-bar' spanning the full-scale support system main struts. The hydraulic ram makes it possible to achieve an angle of attack range up to around 70 degrees with the T-bar.

The entire model support is mounted in the center of a turntable mechanism on the ground board that allows sideslip settings up to (90).

A wide variety of test articles can be accommodated with these balance systems.

The LFST facility is ideal for testing vehicles in formation due to the large open test section and existing model support hardware. The test section is equipped with a main model support located on the test section centerline, capable of angle-of-attack and angle-of-sideslip changes. The tunnel also features an overhead carriage, used for flow surveys, capable of translating in three directions within the test section, horizontally, vertically, and along the free stream. Both the main support and overhead carriage are utilized for these tests. Many types of data can be acquired for both model positions, including static/dynamic forces and moments, surface pressures, and wake surveys.

 

 

 

 

 

 

 

 

 

Performance Data
Test Section Size
Nominal 30 ft. high x 60 ft. wide x 56 ft. long, semi-elliptical cross-section
(9.14 x 18.28 x 17.0 m)
Speed
13 mph to 80 mph (19 ft/sec to 117.3 ft/sec) (6.1 to 35.8 m/s)
Max. Unit Reynolds Number
7.3 x 105 per ft
(2.2 x105 per m)
Operating Temperature
30° F to 120° F
(0° C to 49° C)
Operating Pressure
Atmospheric