Specifications - MIT AeroAstro

Since its dedication in 1938, the Wright Brothers Wind Tunnel has become a campus landmark used for education, research, industry, and outreach. In 2017, MIT AeroAstro announced it would replace the tunnel with a brand-new facility. Today, MIT is home to the most advanced academic wind tunnel in the country, capable of reaching wind speeds up to 230 miles per hour (mph), with the largest test section in U.S. academia.

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At a Glance

Characteristics
Airspeed range	15 mph – 230 mph
Dynamic pressure range	0.5 psf – 135 psf
Flow conditioning	8:1 contraction ratio 4 anti-turbulence screens Honeycomb + screen in fourth-corner vanes Flow-circuit heat exchanger
Drive	2500 hp motor, VFD control to 600 rpm max 16 ft diameter fan, 17 blades, BLI design Leaned + swept stator, 7 cambered vanes
Test section	Dimensions: 12 x 7.75 x 18 ft Corner fillets, tapering 14…10 in At nearly ambient pressure All-glass side walls, 5 windows in ceiling
Model mounting (on external balance)	Metric post and pitch pushrod inside non-metric aero fairing, allowing +/- 30 deg pitch and +/-30 deg yaw OR Metric flange just under floor, allowing +/- 30 deg yaw
Model mounting (on floor turntable)	Non-metric floor turntable, allowing +/- 45 deg yaw
Equipment	Built-in y, z traverse, reaching entire test section Portable 2-axis traverse, 3 x 4 ft reach Pitot-static probes 3-hole and 5-hole probes Pitot rakes Electronic pressure scanning sensors, up to 1 psid 1-axis and 2-axis inclinometers
MATLAB-based test control software	Can control and drive nearly all tunnel functions via GUI and/or custom high-level MATLAB scripts Can interrogate tunnel airflow instruments, main balance, and any custom user instrument output Automates wind-off tares Allows real-time data viewing Logs all data with time stamps Allows data export in a wide variety of formats

External Balance Load Limits (Moment reference point is at center of test section)
Lift	+1500 lb / -500 lb
Drag	+/- 225 lb
Sideforce	+/- 750 lb
Pitching moment	+/-500 ft-lb
Yawing moment	+/-500 ft-lb
Rolling moment (strut mount)	+/-500 ft-lb
Rolling moment (flange mount)	+/- 1500 ft-lb

What is unique about the Wright Brothers Wind Tunnel?

Screened expanding turning vanes

Designed by Prof. Drela, the vanes have enabled the tunnel’s test section volume and area, and its contraction ratio to be almost doubled – without increasing the footprint of the facility, giving much higher air flow quality.

Boundary layer ingesting fan

With 17 uniquely-shaped blades and a 16-foot diameter, the BLI fan is quiet, efficient, and explicitly designed to work with the inflow nonuniformity created by the boundary layer.

State-of-the-art test section

The test section’s sides and top are made of glass so optical sensing techniques such as laser-doppler and particle image velocimetry, ultra violet illumination for advanced fluorescent flow visualization and infrared illumination for motion tracking and aeroelastic deformations can be used.

Faster data collection

A new data acquisition and control system based on MATLAB and Simulink will enable engineers to set up tests faster and easier.

Descriptive Data

Wind Tunnel

Configuration	Closed Circuit
Contraction	8:1
Flow Conditioning	Honeycomb, screen in Corner 4, 4x screens in settling chamber
Corner 1	Airfoil vanes, conventional
Corner 2	Airfoil vanes, expanding (1:1.17)
Corner 3	Formed vanes, conventional
Corner 4	Formed vanes, screened, expanding (1:1.875)
Cooling System	40% propylene glycol, 217 tons
Cooling Coils	3

Test Section

Type	Closed wall, neutral pressure
Inside Width	12 feet 0 inches
Inside Height	7 feet 9 inches
Length	18 feet
Cross Sectional Area	90 sqft
Doors	2
Wall Taper	0 degrees
Boundary Layer Compensation	Tapered corner fillets

Fan System

Wright Brother wind tunnel on campus at MIT on March 30, 2022. Photo by Adam Glanzman

Type	Fixed pitch, rigid in plane
Number of Fans	1
Number of Rotor Blades	17
Rotor Diameter	16 feet
Tip Speed @ 100% RPM	502 FPS
Number of Stator Vanes	7
Drive Configuration	Direct drive

Motor

Number of Motors	1
Make	ABB
Type	AMI 560L8P BAFH
Power	2,500 HP
Volts	4,000
Amps	345
Phase	3
Hertz	40.3
RPM @ 100%	600

Variable Frequency Drive

Number of Drives	1
Make	Rockwell Automation
Type	PowerFlex 7000
Power	2,500 HP
Line Volts	4,160

Limitations

This section includes operation limitations, instrument markings, and basic placards required for safe operation of the wind tunnel and associated systems.

Airspeed Limits

Never Exceed Airspeed (VNE)	230 MPH
Maximum Continuous Airspeed	210 MPH
Maximum Airspeed with Doors Open or Removed	40 MPH

Motor Limits

Maximum Motor Speed	600 RPM
Maximum Motor Current	345 FLA
Maximum Power (Continuous)	2,500 HP
Maximum Winding Temperature	160 Deg C
Maximum Bearing Temperature	105 Deg C

Fan Limits

Maximum Fan Speed	600 RPM
Maximum Vibration	0.3 in/s

Test Section Limits

Maximum Air Temperature	125° F
Minimum Air Temperature	15° F
Maximum Air Pressure	21 psf (4 in-wg)
Minimum Air Pressure	-21 psf (-4 in-wg)

Continuous operation approved with test section doors fully open or removed up to 40 MPH. Operations above 40 MPH require test section doors to be installed and closed.

Note: Operations with test section doors opened or test section doors removed increase turbulence levels, put additional stresses on the wind tunnel equipment, and can lead to premature component wear.

Equipment Limits

Operation prohibited with inoperative safety instruments, equipment protection instruments, or emergency stop buttons and LEDs.

Caution: Operation with inoperative safety instruments and equipment protection instruments can lead to catastrophic failure of critical components, injury, or death.

Operation prohibited with maintenance hatches open or removed.

Tampering with or altering the PLC system is prohibited.

Tampering with or altering the VFD system is prohibited.

Crew Requirements

Minimum crew: 1 operator

The wind tunnel operator must be endorsed as qualified or under the supervision of an operator endorsed as qualified and have received training on normal procedures and emergency procedures of the wind tunnel.

The wind tunnel operator must be stationed or positioned within arm’s reach of a wind tunnel emergency stop button while the wind tunnel is in operation.

Operational Limits

Operations with an empty test section are approved.

Operations with a model in the test section are approved as long as the model is secured and the operator is able to maintain visual contact with the model while the wind tunnel is in operation.

Operations with one or more occupants in the test section are limited to 35 MPH.