SP-4103 Model Research - Volume 2

 

Appendix E

Facilities

 

[507] The NACA used and was used by its facilities. For many years the NACA had the best aeronautical research facilities in the world, and in many ways these facilities determined what the NACA would choose to do and be required to do. Having the world's only full-scale wind tunnel enabled the Committee to perform unique experiments, but it also dictated that the research program make full use of the full-scale tunnel. The same was true of the NACA's other research facilities, so that the agency waged an unending campaign to coordinate the needs of aeronautical research with full exploitation of the equipment on hand, retirement of old equipment, and development of new.

 

HEADQUARTERS

 

Headquarters was always a paper mill. It never conducted original research, nor did it maintain any research facilities other than its technical library. Editing, publishing, and distributing reports was as close as headquarters came to actually doing research; even here, the Langley laboratory performed many of the paperwork functions such as printing, photography, and artwork. The NACA headquarters thus consisted merely of its offices and library, located at the following sites in Washington, D.C.:

 

1915

State, War, and Navy Building, Constitution Avenue, N.W.

1916-1918

Munsey Building, 1329 E Street, N.W.

1918-1920

Bureau of Aircraft Production, Building D, 4th Street and Missouri Avenue, N.W.

1920-1941

Main Navy Building, Constitution Avenue

1941-1947

Leiter Mansion, Dupont Circle, 1500 New Hampshire Avenue, N.W.

1947-1954

1724 F Street, N.W.

1954-1958

Wilkens Building, 1512 H Street, N.W.

1958

Dolley Madison Building, 1520 H Street, N.W., acquired for NASA expansion

 

LABORATORIES

 

The NACA's research was conducted at its laboratories and their subsidiary stations. In order of their establishment and with their various titles, these were:

Langley Aeronautical Laboratory

1920-1958

Langley Memorial Aeronautical Laboratory (1920-1948)

Ames Aeronautical Laboratory

1940-1958

Lewis Flight Propulsion Laboratory

1942-1958

Aircraft Engine Research Laboratory (1942-1947)

Flight Propulsion Research Laboratory (1947-1948)

Pilotless Aircraft Research Station

1945-1958

Auxiliary Flight Research Station (1945-1946)

[507] High Speed Flight Station

1946-1958

NACA Muroc Flight Test Unit (1946-1949)

High Speed Flight Research Station (1949-1954)

Plum Brook Station

1956-1958

 

WIND TUNNELS

 

A fundamental law of fluid dynamics is that a body immersed in a moving fluid experiences the same forces as if the body were moving and the fluid stationary, given that the relative speed of the fluid and the solid object is the same in both cases. This means that the conditions surrounding an airplane in flight can be replicated by holding the plane stationary and moving the air past it at a velocity comparable to flight speeds. Thus, wind tunnels.

Advantages of wind tunnels over flight-testing are economy, safety, and research versatility. A model airplane can be tested in a wind tunnel at a fraction of the cost of building and operating a full-scale prototype, and the airworthiness of new and experimental designs can be tested without risking a pilot's life. Wind-tunnel testing can simulate flight under conditions more controlled and measurable than would be possible in flight test. Even before man first flew, the wind tunnel was the principal tool of the aeronautical engineer.

All wind tunnels have common features that circumscribe their characteristics and capabilities. All have a test section in which an airplane model or component-or even a complete airplane-can be fixed or suspended. The cross section may be round, oval, rectangular, or polygonal. Test sections may vary in size from a few inches up to the 40- by 80-foot dimensions of the Ames full-scale tunnel, still the largest in the world.* The test section may be open, closed, or ventilated.

Wind tunnels may be either return or no return. No return tunnels draw air from the atmosphere, pass it through a tube that includes a test section, and discharge it into the atmosphere. Such tunnels are simple and inexpensive to build, but are inefficient and limited in the types of flow they can generate. Most sophisticated tunnels use a return-type circuit in one of three basic variations. The single-return tunnel passes the same air around a closed loop. Many such tunnels are designed so that the laboratory building encompasses the test section, with the rest of the tunnel winding a circuitous path outside like an overgrown appendage. The double-return tunnel is shaped like a squared figure-eight with the corners rounded and the test section located at the juncture of the two loops. Annular-return tunnels are doughnut-shaped in cross section. Longitudinally, they look like a tube within a capsule; air pushed around the inner shell of the capsule is channeled down the tube in the center, which contains the test section. Annular-return tunnels are generally small and entirely con-tained within their research building.

A major advantage of closed tunnels is that they can be pressurized, a technique that remains one of the NACA's greatest contributions to wind-tunnel technology. Comparability between conditions of wind-tunnel tests on models and conditions experienced by full-scale aircraft in flight depends on a dimensionless mathematical quantity known as Reynolds number (named for the 19th-century British engineer Osborne Reynolds). The Reynolds number is a flow-similarity parameter that describes forces acting on a body in motion with respect to the fluid in which it is immersed. The number is directly proportional to the size of the body and the density and relative.....

 


[
509]

Top, this highlighted view of Langley laboratory's east area taken from directly overhead in 1957 shows the NACA towing tanks (lower right) and the base runway Bottom, a close-up aerial view of the Langley west area taken in 1949; the east area is out of the picture, to the upper right. (LaRC)

Top, this highlighted view of Langley laboratory's east area taken from directly overhead in 1957 shows the NACA towing tanks (lower right) and the base runway. (Not all the highlighted facilities were the NACA 's.) Middle, this aerial view of the Langley laboratory's west area shows the air force base and the east area in the background. Most clearly visible of the east-area facilities are the full-scale wind tunnel shown at the center top and the NACA tanks, extending to the left from the full-scale tunnel into the river. Bottom, a close-up aerial view of the Langley west area taken in 1949; the east area is out of the picture, to the upper right. (LaRC)

 


[
510]

Ames Aeronautical Laboratory as it appeared at the end of World War II, dominated (as it still is) by the full-scale wind tunnel at left center. (ARC)

Ames Aeronautical Laboratory as it appeared at the end of World War II, dominated (as it still is) by the full-scale wind tunnel at left center. (ARC)

 

....speed of the fluid, and inversely proportional to the viscosity of the fluid. Other things being equal, a model "moving" with respect to an airstream would have a smaller Reynolds number than a full-scale plane in flight. The easiest way to equalize the Reynolds numbers-and thus to obtain comparable flow conditions for the plane and the model-is to increase the speed or density of the airstream in which the model is immersed. To increase airspeed within a wind tunnel is a complicated and expensive undertaking that would violate equality of the ratio of airspeed to speed of sound, another condition for strict comparability. In a return-type tunnel, however, it is comparatively easy to increase air density by increasing air pressure. The NACA's first pressurized tunnel-Max Munk's variable-density tunnel of 1923-could pressurize the air to 20 atmospheres, making tunnel results on a 1/2oth-scale model comparable to those of a full-size plane in the atmosphere.

The speed of a wind tunnel is the velocity of the airflow measured at the test section. Tunnels are customarily classified in the following speed ranges:

 

Class

Mach no.**

Mph at sea level

.

Low-speed

0 to 0.5

0 to 380

High-speed

0.5 to 0.9

380 to 684

Transonic

0.7 to 1.4

532 to 1,064

Supersonic

1.4 to 5.0

1,064 to 3,800

Hypersonic

5.0 to 10.0

3,800 to 7,600

Hypervelocity

10.0 and above

7,600 and up

**Mach no. equals stream velocity/velocity of sound.

 


[
511]

Aerial view of Lewis Flight Propulsion Laboratory as it appeared in 1955.

Aerial view of Lewis Flight Propulsion Laboratory as it appeared in 1955. An edge of the Cleveland municipal airport is visible at left center. (LeRC)

 

As aircraft speeds increased, wind-tunnel speeds had to increase. Above 300 to 400 mph, the compressibility of air begins to affect the results of scale-model tests. Thereafter, not only the Reynolds number but also the actual mach number must be matched between the model and the aircraft. A plane moving through the air at low speed sets up something like a bow wave, a layer of compressed air at the leading edges that moves ahead of the plane at the speed of sound, pushing the approaching air out of the way. When the plane moves near or above the speed of sound, the air has no time to get out of the way, and its collision with the plane produces shock waves-patterns of energy dispersion-with unique aerodynamic effects. High-speed wind tunnels are expensive to build and operate (the power required increases as the cube of the speed) and present major problems in turbulence, heating, and flow condensation, but they are indispensable to accurate testing in high-speed regimes of flight. Some of the NACA's greatest achievements were the development and application of high-speed tunnels, especially in the anomalous transonic region.

In most conventional wind tunnels the air is moved by fans powered by electric motors. Some tunnels, however, produce the airstream differently: Blowdown tunnels use a jet of air from a pressurized reservoir. Induction tunnels use a stream of air flowing into a vacuum chamber. Hypervelocity tunnels may combine these methods, passing air from a pressurized vessel across the test section and into an evacuated vessel at pressure ratios of several hundred. Although blowdown and induction-drive systems can produce extremely high-velocity air, they are severely limited by the brief availability of that air and their limited ability to modulate the velocity. At the extreme end of the spectrum is the counterflow tunnel in which a model is shot from a gun into a high-velocity airstream from a blowdown or induction-drive system. Some wind tunnels in the NACA laboratories shared drive systems, and some blowdown tunnels used compressed air stored in nearby pressure tunnels.

These basic characteristics, common to most wind tunnels, by no means encompass all the features, capabilities, and equipment involved in wind-tunnel research. Almost all wind tunnels employ a complex array of balances and other measuring devices designed specifically for the purpose. Most closed-circuit tunnels use tunnel vanes to guide the airflow smoothly around the corners in the circuit. Most tunnels use complex arrays of settling chambers, screens, and throat contractions to smooth and straighten the airstream as it accelerates into the test section. A variety of model-support systems is used, depending on the configuration of the test object. Some [512] tunnels use smoke to help visualize air flow. Some are rigged for Schlieren photography, a special technique that records shock waves produced at high speeds. Some tunnels are refrigerated to produce ice on the models like that encountered under certain flight conditions.

 


Aerial view of the Pilotless Aircraft Research Station, looking north along the Atlantic Ocean, in 1955. (LaRC)

Aerial view of the Pilotless Aircraft Research Station, looking north along the Atlantic Ocean, in 1955. (LaRC)

 

In fact, wind tunnels have been designed to replicate nearly every condition encountered by airplanes in flight. There are vertical wind tunnels to study aircraft spinning characteristics, gust tunnels to determine the effect of fluctuations in the airstream, and curved-flow tunnels with variable geometry in the test section to determine flight characteristics in turns or maneuvers. There are even free-flight tunnels in which the model floats free and the test section cants to simulate different angles of attack.

The characteristics of a tunnel are not necessarily fixed permanently during construction. Many NACA tunnels saw long and varied service, upgraded to incorporate advances in wind-tunnel technology that adapted them to modern regimes of flight. The most frequent modification was repowering to produce higher velocities in the test section. Improved instrumentation and mountings were less dramatic but equally important.

The complexity of NACA tunnels-the vague distinction between a tunnel's basic equipment and the changing battery of auxiliary equipment that supported it, the shared housings and drive systems that many tunnels employed, and the repeated modifications that some tunnels underwent-makes it difficult to present a uniform picture of tunnel characteristics. Still more difficult to achieve is an accurate estimate of costs. The following lists contain the available data on the test section, circuit, speed,....

 


[
513]

So versatile and practical is the wind tunnel that it is called upon for all kinds of research tasks. Above, a mockup of the Vought-Sikorsky V-173, set up in Langley s full-scale wind tunnel in 1941. Below, a submarine model mounted in the same tunnel in the 1950s; since air and water have comparable flow characteristics, a boat's performance under water could be predicted in such tests. (LaRC)

So versatile and practical is the wind tunnel that it is called upon for all kinds of research tasks. Above, a mockup of the Vought-Sikorsky V-173, set up in Langley s full-scale wind tunnel in 1941. Below, a submarine model mounted in the same tunnel in the 1950s; since air and water have comparable flow characteristics, a boat's performance under water could be predicted in such tests. (LaRC)

 

 

[514] ....and drive systems of all major NACA tunnels. Cost information is not sufficiently reliable to merit inclusion, but one example will suggest the range of expenses involved. The first NACA wind tunnel (the 5-foot atmospheric tunnel built at Langley in 1920) cost about $45,000. The 10-by 10-foot supersonic tunnel built at Lewis in the early 1950s cost $35,000,000.

 

RESEARCH FACILITIES OTHER THAN WIND TUNNELS

 

The wind tunnel that dominated NACA research could not provide all the answers the Committee needed to solve the problems of flight. Over the years the NACA constructed other research laboratories, buildings, and equipment to answer questions not aerodynamic in nature. These facilities are especially hard to trace because they frequently had no building of their own but occupied space in office buildings that housed a number of research functions. No attempt has been made to inventory these facilities in the same detail as the NACA wind tunnels, but a list of major nontunnel facilities at Langley may indicate the great variety of NACA equipment. Langley had more of these facilities than any other laboratory or station.

 

Facility

Operational Date

.

NACA [Towing] Tank No. 1

1931

Aircraft Engine Research Laboratory

1934

Structures Laboratory

1940

Seaplane Impact Basin

1942

NACA Tank No. 2

1942

Helicopter Apparatus

1944

Aircraft Loads Building

1945

Aircraft Loads Calibration Laboratory

1945

Physical Research Laboratory

1945

Instrument Research Laboratory

1946

Pilotless Aircraft Research Laboratory

1946

Landing Loads Track

1955

High-Speed Hydrodynamics Facility

1956

 

Note the rapid tempo of expansion of facilities during World War II, a measure of the NACA's concentration on wind-tunnel research in the 1920s and 1930s. And compare the small number of these with the extensive family of tunnels described in the following section.

 

Langley Aeronautical Laboratory

5-Foot Atmospheric Wind Tunnel (NACA Wind Tunnel No. 1) Test Section: 5-foot diameter (1.52 m), closed-throat
Circuit/pressure: Nonreturn/atmospheric
Maximum speed: 40 m/sec (89 mph)
Drive system: 200-hp (149-kw) electric motor/fan Operational date: 11 June 1920 Disposition: Dismantled in 1930 Notes: Modeled after an early tunnel at the National Physical Laboratory in Britain; primitive for its time.
References: F. H. Norton, "National Advisory Committee's 5-Foot Wind Tunnel," Journal of the Society of Automotive Engineers (21 May 1921): 1-7; TR-l95, p. 208 (diagram)

 

[515] Variable-Density Tunnel

Test section: 5-foot diameter (1.52 m), closed-throat
Circuit/pressure: Annular return/20 atmospheres
Maximum speed: 23 m/sec (51 mph)
Drive system: 250-hp (187-kw) electric motor/fan
Operational date: March 1923
Disposition: Only pressure shell remains
Notes: Designed by Max Munk; proposed in 1921; converted to open-throat in April 1928 after damage to the original in fire of August 1927; returned to closed-throat design in major remodeling in Dec. 1930 because the open-throat arrangement did not work properly. References: TRs-185,-227,-416

 

Propeller-Research Tunnel

Test section: 20-foot diameter (6.1 m), open-throat
Circuit/pressure: Double return/atmospheric
Maximum speed: 49.1 m/sec (110 mph)
Drive system: Two 1,000-hp diesel engines (746 kw each)/fan
Operational date: July 1927
Disposition: Dismantled in 1950 to make way for 8-foot Transonic Pressure Tunnel.
Notes: Proposed by Fred Weick; designed by Max Munk and Elton W. Miller; design
and construction begun in 1925.
References: TR-300

 

5-Foot Vertical Wind Tunnel

Test section: 5-foot-diameter (1.52 m), open-throat
Circuit/pressure: Single-return/atmospheric
Maximum speed: 35.8 m/sec (80 mph)
Drive system: 50-hp (37.3-kw) electric motor/fan
Operational date: 1930
Disposition: Deactivated
Notes: Designed to investigate spinning characteristics; converted to 4-by 6-foot
closed-throat configuration in 1938.
References: AR 1930; TR-387

 

Atmospheric Wind Tunnel (AWT) (7- by 10-Foot Wind Tunnel)

Test section: 7- by 10-foot (2m by 3m), closed-throat
Circuit/pressure: Single-return/atmospheric
Maximum speed: 35.8 rm/sec (80 mph)
Drive system: 200-hp (149-kw) electric motor/fan
Operational data: Summer 1930
Disposition: Deactivated
References: TR-412

 

Full-Scale Tunnel

Test section: 30- by 60-foot (9.1 x 18.3m), open-throat
Circuit/pressure: Double-return/atmospheric
Maximum speed: 57.2 m/sec (118 mph)

 


[
516]

The view down the air-return passage in the Langley full-scale wind tunnel dwarfs two workers standing by the guide vanes. (LaRC)

The view down the air-return passage in the Langley full-scale wind tunnel dwarfs two workers standing by the guide vanes. (LaRC)

 

Drive system: Two 4,000-hp (2,984 kw each) electric motors/fan
Operational date: Spring 1931
Disposition: Operational
Notes: Underwent major rehabilitation in 1977 with no change in performance.
References: TR-459

 

11-inch High-Speed Tunnel

Test section: 11-inch (0.3m) diameter, closed-throat
Circuit/pressure: Nonreturn/atmospheric
Maximum speed: Ml
Drive system: Compressed air from variable-density tunnel; induction drive
Operational date: 3 March 1932
Disposition: See notes
Notes: Successor to the 12-inch open-throat tunnel designed in 1927 and operated 1928-1932.
References: TR-463

 

24-Inch High-Speed Tunnel

Test section: 24-inch (0Gm) diameter, closed-throat3
Circuit/pressure: Nonreturn, atmospheric
Maximum speed: M1
Drive system: Injector drive; blowdown from variable-density tunnel
Operational date: 3 October 1934
Disposition: See notes Notes:
Produced the first Schlieren
photographs at LMAL; enclosure installed 29 Aug. 1949.
References: TR-646

 

[517] 15-Foot Spin Tunnel (15-Foot Free-Spinning Tunnel)

Test section: 15-foot diameter/open-throat; 12-sided polygon/closed-throat 2
Circuit/pressure: Nonreturn/atmospheric
Maximum speed: 18 rn/sec (40 mph), variable to rate of fall of aircraft model
Drive system: 150 hp2
Operational date: March 1935
Notes: Modeled on British tunnel of 1932.
References: TR-557; Aero Digest (June 1935): 20-22

 

8-Foot High-Speed Wind Tunnel

Test section: 8-foot-diameter (2.44 m), closed-throat
Circuit/pressure: Single-return/atmospheric
Maximum speed: M 0.75
Drive system: 8,000-hp (5968-kw) electric motor/fan
Operational date: March 1936
Disposition: Deactivated 1956
Notes: The only NACA tunnel with external concrete walls, constructed with WPA funds; repowered in Feb. 1945 to 16,000 hp, M 1 capability; slotted throat installed in 1950; increased to 25,000 hp in 1953 to yield M 1.2; the tunnel used to verify the area rule.
References: AR-1936

 

 


A researcher <<flies>> a model (center) in the Langley laboratory's 5-foot free-flight tunnel.(LaRC)

A researcher "flies" a model (center) in the Langley laboratory's 5-foot free-flight tunnel.(LaRC)

 

[518] 5-Foot Free-Flight Tunnel

Test section: 5-foot (1.5m) diameter
Circuit/pressure: Nonreturn/atmospheric
Maximum speed: 25 ft/sec. (7.6 m/sec)
Drive system: 5 hp (3.7 kw)
Operational date: 1937
Disposition: Replaced by 12-foot free-flight tunnel in 1939

 

Two-Dimensional Low-Turbulence Tunnel (Ice Research Tunnel)

Test section: 3- by 7.5-foot (0.9 m x 2.3 m), closed-throat
Circuit/pressure: Single-return/atmospheric
Maximum speed: 69 rm/sec (155 mph)
Drive system: 200-hp (149-kw) electric motor/fan
Operational date: April 1938
Disposition: Dismantled
References: TN-l283

 

19-Foot Pressure Tunnel

Test section: 19-foot (5.8 m) diameter, closed-throat
Circuit/pressure: Single return/0 to 40 psia (2.72 atm.)
Maximum speed: 330 mph (100 m/sec), atm. pressure
Drive system: 8,000-hp (5,968-kw) electric motor/fan
Operational date: December 1939
Notes: Designed by John F. Parsons under Smith J. DeFrance for high Reynolds-number research on problems of low-speed high-lift stability and control; converted to transonic dynamics tunnel in 1954.

 

12-Foot Free-Flight Tunnel

Test section: 12-foot (3.7 m) 12-sided 2/8-sided polygon1
Circuit/pressure: Annular return/atmospheric1; 2 atm. (max.)
Maximum speed: 50 mph (15.2 m/sec)
Drive system: 600-hp (447-kw) electric motor/fan
Operational date: 1939
Notes: Undertaken in 1937 on the basis of success of the 5-foot free-flight tunnel; inclination and airspeed of tunnel matched to normal glide pattern of model.

 

Low-Turbulence Pressure Tunnel

Test section: 3- by 7.5-foot (0.9 x 2.3 m), closed-throat
Circuit/pressure: Single-return/150 psia
Maximum speed: M 0.22 to 0.45
Drive system: 2,000-hp (1,492-kw) electric motor/fan
Operational date: May 1941
Notes: Designed by Eastman Jacobs and Ira Abbott; operated briefly with freon gas as the test medium. Still operational.
References: TN-1283

 


[
519]

Above, a phantom drawing of the Langley 19-foot pressure tunnel shows the test section at the front center, the turning vanes at the four comers, and the dime fan at the left rear. The air moves clockwise. Below, a technician mounts a model of Republic Aviation FO4F in the test section. (LaRC)

Above, a phantom drawing of the Langley 19-foot pressure tunnel shows the test section at the front center, the turning vanes at the four comers, and the dime fan at the left rear. The air moves clockwise. Below, a technician mounts a model of Republic Aviation FO4F in the test section. (LaRC)

 


[
520]

From the outside, Langley's 16-foot high-speed tunnel is an imposing but comprehensible building. Inside, however, is an awesome and beguiling world of shadows, deceptive scale, and optical illusions. Though the wind tunnel helps the researcher see flight more clearly, it also has the capacity to cause tunnel vision-to make the tool an end in itself (LaRC)

From the outside, Langley's 16-foot high-speed tunnel is an imposing but comprehensible building. Inside, however, is an awesome and beguiling world of shadows, deceptive scale, and optical illusions. Though the wind tunnel helps the researcher see flight more clearly, it also has the capacity to cause tunnel vision-to make the tool an end in itself (LaRC)

 

20-Foot Spin Tunnel (20-Foot Atmospheric Free-Spinning Tunnel)

Test section: 20-foot (6.1 m), 12-sided, closed-throat
Circuit/pressure: Annular-return/atmospheric
Maximum speed: 0 to 30 sec/sec (0 to 66 mph)
Drive system: 400-hp (298-kw) electric motor/fan (1,300 hp overload)
Operational date: March 1941
References: NACA L-86258

 

16-Foot High-Speed Tunnel

Test section: 16-foot diameter, closed-throat
Circuit/pressure: Single-return/atmospheric
Maximum speed: M 0.7
Drive system: 16,000 hp (11,936 kw) electric motor/single fan
Operational date: November 1941
Disposition: Operational as 16-foot transonic tunnel
Notes: Repowered in 1950 with 60,000-hp drive and 14-foot slotted test section (M 1.1); in 1969 added 35,000-hp plenum suction blower (M 1.3).

 

Stability Tunnel

Test section: Dual: 75-in (1.9 m) diameter; 6- by 6-foot (1.8 m) curved flow
Circuit/pressure: Single-return/atmospheric
Maximum speed: 56 m/sec (125 mph)
Drive system: 600-hp (447-kw) electric motor/fan
Operational date: June 1942
Disposition: Deactivated
Notes: Specially designed for testing in rotational and curved flow; transferred to
Virginia Polytechnic Institute in 1958.
References: TN-2483

 

[521] 9-Inch Supersonic Tunnel

Test section: 9-in by 9-in (0.23 m x 0.23 m)
Circuit/pressure: Single-return,1 nonreturn/atmospheric
Maximum speed: M 2.5
Drive system: 1,000 hp1
Operational date: July 1942, June 19431
Disposition: Dismantled
Notes: Adjustable nozzle abandoned in favor of fixed nozzle.

 

Gust Tunnel

Test section: 8- by 14-foot (2.4 m x 4.3 m), open-throat1
Circuit/pressure: Nonreturn/atmospheric
Maximum speed: M 0.04 to 0.131
Drive system: 75 hp1
Operational date: August 1945
Notes: Designed for research on aircraft loads produced by atmospheric turbulence.

 

Flutter Tunnel

Test section: 4.5-foot diameter, closed-throat2
Circuit/pressure: Closed-return/0 to 1.8 atmospheres2
Maximum speed: M 12
Drive system: 1,000 hp2, 1,400 hp1
Operational date: September 1945

 

300-Mph 7- by 10-Foot Tunnel

Test section: 7- by 10-foots (2.1 m x 3.1 m), closed-throat
Circuit/pressure: Single-return/atmospheric
Maximum speed: 134 rm/sec (300 mph)
Drive system: 1,600-hp (1,193-kw) electric motor/fan
Operational date: February 1945
Disposition: Dismantled 1970
Notes: Two test sections: 7- by 10-foot-300 mph; 17- by 15.8-foot- 8 mph.

 

High-Speed 7- by 10-Foot Tunnel

Test section: 7-by 10-foot (2.1 m x 3.1 m), closed-throat
Circuit/pressure: Single-return/pressure
Maximum speed: M 0.9
Drive system: 14,000-hp (10,444-kw) electric motor/fan
Operational date: November 1945
Notes: Slotted test section installed, capability to M 1; connected to 35,000-hp compressor of 16-foot transonic tunnel for transonic operations, M 1.2.

 

11-Inch Hypersonic Tunnel

Test section: 11- by 11-in (0.3 m x 0.3m)
Circuit/pressure: Nonreturn/540 psi max (36 atm)
Maximum speed: M 7
[522] Drive system: Blowdown
Operational date: 1947
Notes: Proposed by John Becker as forerunner of supersonic tunnel; pilot model for 5-0 mach tunnel; electric resistance heater raised temperature in settling chamber to 900° F.

 

4-by 4-Foot Supersonic Tunnel

Test section: 4.5- by 4.5-foot (1.4 m x 1.4 m), template adjusted, flexible wall nozzles
Circuit/pressure: Single-return/sub atmospheric
Maximum speed: M 1.25 to 2.2
Drive system: 6,000-hp (4,476-kw) electric motor/fan
Operational date: 20 May 1948
Disposition: Dismantled 1977
Notes: Repowered in August 1950 to 45,000-hp, 2.5 atmospheres pressure, M 2.6.

 

 


With the stationary housing blades removed, technician inspects the rotor blades of the compressor in Langley's 4-foot supersonic wind tunnel. (LaRC)

With the stationary housing blades removed, technician inspects the rotor blades of the compressor in Langley's 4-foot supersonic wind tunnel. (LaRC)

 

 

26-Inch4 Transonic Blow down Tunnel

Test section: 26-in octagon
Circuit/pressure: Nonreturn/7 atm (max)
Maximum speed: M 0.6 to 1.45
Drive system: Blow down
Operational date: 1950
[523] Disposition: No longer operational
Notes: Blow down from low-turbulence pressure tunnel, 150 psi.

 

Gas-Dynamics Laboratory (Hypersonic Aero thermal-Dynamics Facility)

Test section, circuit/pressure, maximum speed, drive system: Central 3,000 psi (204 atm) tank farm provides heated air to several small blow down tunnels. Mmax with air is 8.
Operational date: 1951
Disposition: Operational. High-pressure nitrogen and helium supply also available

 

8-Foot Transonic Pressure Tunnel

Test section: 7.1- by 7.1-foot (2.2 m x 2.2 m), slotted-throat
Circuit/pressure: Single-return/0.1 to 2.0 atmospheres
Maximum speed: M 0.2 to 1.2
Drive system: 25,000-hp (18,650-kw) electric motor/fan
Operational date: 1953
Notes: Plenum suction added in 1958-increased speed to M 1.3.

 

Unitary 4- by 4-Foot Supersonic Tunnel

Test section: 4- by 4-foot (1.2 m x 1.2 m)/asymmetric nozzle
Circuit/pressure: Single-return/150 psia
Maximum speed: M 1.5 to 4.6
Drive system: 83,300-hp (62,140-kw) electric motor/4 compressor units
Operational date: 1955
Notes: Two separate test sections: low, M 1.5 to 2.9; high, M 2.3 to 4.6.

 

9-by 6-Foot Thermal Structures Tunnel

Test section: 8.75- by 6-foot (2.7 m x 1.8 m), solid wall
Circuit/pressure: Nonreturn/50 to 200 psia (3.4 to 13.6 atm), 300 to 660°F (149 to 349°C) Maximum speed: M 3
Drive system: Blow down from 600-psia tank farm
Operational date: September 1957
Disposition: Deactivated 30 September 1971
Notes: Running time was 75 sec at 50 psia, 18 sec at 200 psia; hot core capability added in 1963 by propane burning; closed by rupture of 600-psia tank farm in 1971.

 

20-Inch Hypersonic Tunnel

Test section: 20-in diameter
Circuit/pressure: Nonreturn
Maximum speed: M 6
Drive system: Blowdown
Operational date: 1958
Disposition: Operational
Notes: A workhorse tunnel for inlets and complete models.

 

[524] Ames Aeronautical Laboratory

 

7- by 10-Foot Tunnel Nos. 1 and 2
 
Test section: 7- by 10-foot (2.1 m x 3.1 m), closed-throat
Circuit/pressure: Single-return/atmospheric
Maximum speed: 112 rm/sec (250 mph)
Drive system: 1,800-hp (1,343-kw) electric motor/fan
Operational date: No. 1: March 1940; No. 2: July 1940

 

16-Foot High-Speed Tunnel

Test section: 16-foot (4.9 m) diameter, closed-throat
Circuit/pressure: Single-return/atmospheric
Maximum speed: M 1
Drive system: 27,000-hp (20,142-kw) electric motor/fan
Operational date: December 1941
Notes: Repowered in 1955 to 110,000 hp (82,060 kw) with 14- by 14-foot (4.3 m x 4.3 m) transonic test section, M 1.2.

 

40- by 80-Foot Wind Tunnel

Test section: 40- by 80-foot (12.2 m x 24.4 m), closed-throat
Circuit/pressure: Single-return/atmospheric
Maximum speed: 103 m/sec (230 mph)
Drive system: Six 6,000-hp (4,476-kw) electric motors/fan
Operational date: June 1944
Notes: Power increased in 1979 to 135,000 hp (100,710 kw), M 45; 80- by 120-foot leg (24.4 m x 36.6 m) added.

 

1- by 3.5-Foot High-Speed Tunnel

Test section: 1- by 3.5-foot1 (0.3 m x 1.1 m)
Circuit/pressure: Closed-circuit 1/atmospheric2
Maximum speed: M 1.21
Drive system: 2,000 hp1 (1,492 kw)
Operational date: January 1944

 

1- by 3-Foot Supersonic Tunnel

Test section: 1- by 3-foot (0.3 m x 0.9 m)
Circuit/pressure: Closed-circuit1/4 atm
Maximum speed: M 1.4 to 2.21
Drive system: 11,500 hp1 (8,579 hp)
Operational date: 1946

 

12-Foot Pressure Tunnel

Test section: 12-foot (3.7 m) diameter, closed-throat
Circuit/pressure: Single-return/0.2 to 5 atmospheres
Maximum speed: M 0.98
Drive system: 12,000-hp (8,952-kw) electric motor/fan
Operational date: July 1946
Notes: Exceptionally low turbulence level.

 

 


[
525]

The size of the Ames 40- by 80-foot full-scale wind tunnel is evident in these two internal photographs. Above, an automobile parked inside the tunnel (above) is about the size of each of the six motors that power the airflow. A man stands beside one of the propeller blades of the lower left mount. Below, turning vanes in the tunnel tower over two workers on the tunnel floor. (ARC)

The size of the Ames 40- by 80-foot full-scale wind tunnel is evident in these two internal photographs. Above, an automobile parked inside the tunnel (above) is about the size of each of the six motors that power the airflow. A man stands beside one of the propeller blades of the lower left mount. Below, turning vanes in the tunnel tower over two workers on the tunnel floor. (ARC)

 

[526] 6-by 6-Foot Supersonic Tunnel

Test section: 6- by 6-foot (1.8 m x 1.8 m), sliding block asymmetric nozzle
Circuit/pressure: Single-return/0.3 to 1 atmosphere
Maximum speed: M 1.3 to 1.8 (continuously variable)
Drive system: 60,000-hp (44,760-kw) electric motors/2 compressors
Operational date: 16 June 1948
Notes: Modified in 1956 to provide subsonic/transonic capability, M 0.3 to 2.2.

 

Supersonic Free-Flight Tunnel

Test section: 1- by 2-foot closed-throat
Circuit/pressure: Nonreturn/6 atmospheres
Maximum speed: M 2; gun velocity, 1,000 to 6,000 ft. sec (305 to 1,829 m/sec), Mrel 2 to 10
Drive system: Compressor system from 12-foot pressure tunnel
Operational date: 1949
Notes: Projectile fired upstream; produces shadowgraphs.
Reference: TR-1222

 

2- by 2-Foot Transonic Tunnel

Test section: 2- by 2-foot (0.6 m x 0.6 m) /ventilated wall
Circuit/pressure: Single-return/0.2 to 3 atm
Maximum speed: M 0.2 to 1.4
Drive system: 4,000-hp (2,984-kw) electric motor
Operational date: 1951
Reference: NASA SP-4302

 

Unitary 11- by 11-Foot Transonic Tunnel

Test section: 11- by 11-foot (3.6 m x 3.6 m), slotted wall
Circuit/pressure: Single-return/0.5 to 2.25 atmospheres
Maximum speed: M 0.7 to 1.4
Drive system: 180,000-hp (134,280-kw) electric motor/3-stage fan
Operational date: 1955
Notes: Drive motors shared with supersonic legs.

 

Unitary 9-by 7-Foot Supersonic Tunnel

Test section: 9- by 7-foot (2.7 m x 2.1 m), asymmetric nozzle
Circuit/pressure: Single-return/0.3 to 2 atmospheres
Maximum speed: M 1.55 to 2.5
Drive system: 180,000-hp (134, 280-kw) electric motor/11-stage compressor
Operational date: 1955
Notes: Common drive leg with 8- by 7-foot supersonic tunnel; drive motors shared with transonic leg.

 

[527] Unitary 8- by 7-Foot Supersonic Tunnel

Test section: 8- by 7-foot (2.4 m x 2.1 m), symmetrical flexible wall
Circuit/pressure: Single-return/0.3 to 2 atmospheres
Maximum speed: M 2.5 to 3.5
Drive system: 180,000-hp (134,280-kw) electric motor/ 11-stage compressor
Operational date: 1955
Notes: Drive leg shared with 9- by 7-foot supersonic tunnel; drive motors shared with transonic leg.

 

10- by 14-Inch Hypersonic Tunnel

Test section: 10- by 14-in (0.3 m x 0.4 m), closed-throat, variable-geometry supersonic nozzle
Circuit/pressure: Nonreturn/6 atmospheres
Maximum speed: M 2.7 to 6.3
Drive system: Existing compressors from 12-foot pressure tunnel
Operational date: 1950
Notes: Low-energy start via double-hinged fixed-contour nozzle blocks; boundary layer control at second throat.
Reference: TN 3095

 

14-Foot Transonic Tunnel

Test section: 13.5- by 13.7-foot (4.1 m x 4.2 rm), perforated wall
Circuit/pressure: Single-return/ atmospheric
Maximum speed: M 0.6 to 1.2
Drive system: 110,000-hp (82,060-kw) electric motor/3-stage fan
Operational data: 1956
Notes: Adjustable flexible-wall nozzle ahead of test section.

 

1-Foot Hypervelocity Tunnel

Test section: 1-foot diameter
Circuit/pressure: (Not applicable)
Maximum speed: M 10
Drive system: 60,000-hp (44,700-kw) electric motor
Operational date: 1957
Disposition: Demolished in 1972
Notes: Run duration, 180 milliseconds; converted in 1967 to 42-in, shock tunnel.
References: TN D-1428

 

Lewis Flight Propulsion Laboratory

 

Altitude Wind Tunnel

Test section: 20-foot (6.1 m) diameter, closed- or open-throat
Circuit/pressure: Single-return/0.1 to 1 atmosphere
Maximum speed: 224 sec/sec (500 mph) at altitude conditions
Drive system: 18,000-hp (13,428-kw) electric motor/fan
Operational date: 1944
Disposition: Deactivated 1958
Notes: Designed for altitude propulsion-system testing; used after 1958 as a rocket test cell.

 


[
528]

Schematic diagram of the altitude wind tunnel and associated facilities at the Lewis laboratory. (LeRC)

Schematic diagram of the altitude wind tunnel and associated facilities at the Lewis laboratory. (LeRC)

 

Icing Research Tunnel

Test section: 6- by 9- foot (1.8 m x 2.7 m), closed-throat
Circuit/pressure: Single-return/atmospheric
Maximum speed: 134 rm/sec (300 mph)
Drive system: 4,160-hp (3,103-kw) electric motor/fan
Operational date: 1944
Notes: 2,100-ton refrigeration system cools tunnel air to -40°F (4°C): water sprays provided.

 

8- by 6-Foot Supersonic Tunnel

Test section: 8- by 6-foot (2.4 m x 1.8 m), flexible-wall nozzle, perforated4
Circuit/pressure: Nonreturn/maximum pressure 1.75 atmospheres at M 2
Maximum speed: M 1.4 to 2.0
Drive system: 87,000-hp (64,900-kw) electric motors/7-stage axial flow compressor
Operational date: 1949
Notes: Converted to open/closed return; added transonic section and vertical takeoff and landing section. M 0.36 to 2.0 (primary test section).

 

Unitary 10- by 10-Foot Supersonic Tunnel

Test section: 10- by 10-foot (3.1 m x 3.1 m), symmetric nozzle
Circuit/pressure: Return or nonreturn
Maximum speed: M 2.0 to 3.5
Drive system: 250,000-hp (186,500-kw) electric motors/fan
Operational date: 1955
Notes: Designed for propulsion-system testing; can be run open to the atmosphere.
References: TM X-71625

 


*At the time of this writing, the tunnel was being modified to provide an 80- by 120-foot test section.


-
Notes -

Unless otherwise indicated, all data on the NACA wind tunnels was derived from Donald D. Baals and William R. Corliss, Wind Tunnels of the National Aeronautics and Space Administration (SP-440; Washington: NASA, 1981).

1. Research and Development Board, Committee on Aeronautics. "U.S. and Foreign Wind Tunnels in Operation, under Construction, or Authorized," AR 26/11.5, 4 Feb. 1948.

2. The Working Committee of the Aeronautical Board, "Survey of Wind Tunnels," preliminary copy, 1 Jan. 1947.

3. Alan Pope, Wind Tunnel Testing (New York: John Wiley and Sons, Inc., 1947), pp. 16-29.

4. Bernard A. Goethart, Transonic Wind Tunnel Testing, ed. by Wilbur C. Nelson (New York: Pergamon Press, 1961), pp. 383-89.


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