National Aeronautics and Space Administration

www.nasa.gov

20-Foot Vertical Spin

Tunnel

NASA’s Aeronautics Test Program

Orion Launch Abort System model being tested in the VST.

Maneuvering aircraft may encounter a dangerous condition known as spin, caused by a 

sudden loss of lift over wings or control surfaces. NASA’s 20-Foot Vertical Spin Tunnel 

(VST) is the only operational tunnel of its kind in the Western Hemisphere that conducts 

free-spin research using dynamically scaled, free-flying models. The VST is a closedthroat, annular-return facility that operates at nominal atmospheric conditions, with 

velocities that can be rapidly adjustable up to 85 ft per sec.

VST studies identify and quantify spin and spin-recovery characteristics of a given vehicle 

configuration. Related tumbling research identifies susceptibility to out-of-control pitch 

autorotation and strategies for safe recovery. Forced-oscillation capability has recently 

been added to the tunnel’s rotary balance in order to measure 

body-axis rate-damping characteristics.

The VST has supported the development of nearly all U.S. 

military fighter and attack airplanes, trainers and bombers, as 

well as some foreign designs. It is the only resource available to 

commercial aircraft manufacturers for proprietary spin-and-tumble 

assessments of their products in a wind tunnel environment. 
M–1870–4

May 09

NASA’s Aeronautics Test Program www.aeronautics.nasa.gov/atp

Contact Information

www.aeronautics.nasa.gov/atp

Thomas G. Ivanco

NASA Langley Research Center

Phone: 757.864.5092

E-mail: wte+fm_20ft@larc.nasa.gov

Characteristics

Test section dimensions 25 ft high by 20 ft wide

Area 300 ft2

Speed Mach 0.08

Reynolds number 0.55×106 per ft

Pressure Atmospheric

Temperature Ambient

Test gas Air

Contraction area ratio 5:1

Drive power 400 hp continuous and 1300 hp in short bursts

Data Acquisition and Processing

Inputs Analog balance voltages, digital model altitude, and 

electronically scanned pressure (ESP) system

Controller Proprietary and Open Architecture Data Acquisition 

Systems (OADAS)

Capacity/channels Analog/128, Digital/32, and ESP/2048

Dynamic data acquisition Yes

Classified capability Yes

Facility Benefits

• A variety of miscellaneous instruments, including hand-held

anemometers, force gauges, electronic levels, and digital volt

meters are available to users

• Direct observation of tests is available through panoramic control

room windows

• Recording views of models and the test section during tunnel

operation is possible using in situ S–VHS or digital video cameras,

time-code generators, and recording media

Facility Applications

• Spin mode analysis, identification

of recovery control strategies, and

emergency spin-recovery parachute sizing

are accomplished in the VST. Nearly all

U.S. high-performance fighter, attack, and

trainer aircraft, as well as some bombers,

foreign designs, small parachutes, and

several general aviation aircraft have been

tested at the VST.

• The VST has provided key subsonic,

dynamic stability data for many noncrewed and human-rated atmospheric

entry vehicles. Examples include Pioneer

Venus, Stardust, and Mars Sample Return

prototypes and the Mercury, Gemini, and

Apollo space capsules.

• Most recently, the VST is contributing

to development of NASA’s Orion crew

exploration vehicle with subsonic dynamic

stability assessments of the Orion Launch

Abort Vehicle and crew module, drogue

parachute performance, and rotary

balance studies of the Blended Wing Body

and ARES Mars Airplane configurations.