report > historic structures report 12-foot low-speed ... · air-distribution was possible....

REPORT >

Historic Structures Report 12-Foot Low-Speed Tunnel (Building 644) NASA Langley Research Center DATE> JULY, 2013 LOCATION > Hampton, Virginia PREPARED FOR >

Straughan Environmental, Inc

PREPARED BY > Dutton + Associates, LLC

Dutton + Associates CULTURAL RESOURCE SURVEY, PLANNING, AND MANAGEMENT

NASA LANGLEY RESEARCH CENTER, VDHR # 114-5313-0405 12-FOOT LOW-SPEED TUNNEL (12-Foot Free-Flight Tunnel; Building 644) 644 Andrews Street NASA Langley Research Center Hampton Virginia

PHOTOGRAPHS WRITTEN HISTORICAL AND DESCRIPTIVE DATA

Historic Structure Report Virginia Department of Historic Resources

Richmond, Virginia

HISTORIC STRUCTURES REPORT

NASA LANGLEY RESEARCH CENTER 12-FOOT LOW-SPEED TUNNEL

(12-Foot Free-Flight Tunnel; Building 644)

VDHR ID# 114-5313-0405 Location: The 12-Foot Low-Speed Tunnel (NASA Building 644) is located in the

NASA Langley Research Center (LaRC) East Area at 644 Andrews Street. NASA LaRC is located within the City of Hampton, Virginia.

The 12-Foot Low-Speed Tunnel is located at latitude: 37.078886,

longitude: -76.343683. This coordinate represents the approximate center of the facility. This coordinate was obtained on June 3, 2013, using Google Earth. The datum used for this point is North American Datum 1983. The tunnel’s location is restricted to the public.

Date of Construction: 1939 Present Owner: United States National Aeronautics and Space Administration (NASA) Present Use: Research and Development Significance: The NASA LaRC 12-Foot Low-Speed Wind Tunnel (Building 644) is a

significant historic resource at the national level for its association with advances in aerodynamics research and testing conducted by the National Advisory Committee for Aeronautics (NACA) and NASA LaRC. The 12-Foot Free-Flight wind tunnel was constructed in 1939 to assist researchers studying the problems of stability and control. The desire was to allow researchers to "fly" dynamic scale models within the controlled conditions of a wind tunnel. This tunnel followed the successfully developed 5-Foot Free-Flight wind tunnel in 1937. The 12-Foot Free-Flight Tunnel enabled Langley staff to pursue research into the poorly understood tailspin phenomenon. Testing in the tunnel was highly successful, leading to advances in aircraft design to limit tailspin incidents, as well as pilot control to recover from these events.

Historian(s): Robert J. Taylor, Jr., Dutton + Associates, LLC, Richmond, Virginia.

Report completed June 2013. Project Information: This Historic Structures Report was prepared by Dutton + Associates,

LLC for NASA Langley Research Center under contract with Straughan

NASA LANGLEY RESEARCH CENTER, 12-FOOT LOW-SPEED TUNNEL

VDHR ID# 114-5313-0405 (Page 2)

Environmental, Inc in compliance with the National Historic Preservation Act (NHPA) of 1966 as amended, and to satisfy the standard documentation requirements of the Programmatic Agreement (PA) among NASA, the Virginia State Historic Preservation Office and the Advisory Council on Historic Preservation for Management of Facilities, Infrastructure and Sites at NASA LaRC (dated January 15, 2010). Stipulation V.G of the PA provides for implementing Standard Documentation Measures when LaRC plans to demolish an historic building or structure. Architectural fieldwork, preparation of descriptions and historical context, and photography were completed by D+A Architectural Historian, Robert J. Taylor, Jr. Historical information and assistance was provided by NASA LaRC and Straughan. This package was prepared under consultation with the Virginia Department of Historical Resources (VDHR).


VDHR ID# 114-5313-0405 (Page 3)

PART I. HISTORICAL INFORMATION

A. Physical History:

1. Date of Construction: 1937-39

2. Designers: Charles H. Zimmerman

3. Contractors: Tunnel Structure: [unknown] Bridge and Iron Company, Richmond Engineering Company, W.P Thurston Company. Shop Office and Connecting Building: E.T. Greshman and Company, Inc., Britingham Company, C.W. Lockwood 4. Original Plans: The current plan and configuration of the 12-Foot Low-Speed Tunnel roughly matches the original plan for the facility as constructed. Construction on the spherical wind tunnel structure which encloses the test unit was begun in late-1937 and completed in mid-1938. The spherical shape was used to support the tilting test section so that no matter the angle of the study, uniform air-distribution was possible. Following completion of the wind tunnel structure, the associated office building where the control room and work shop were located was initiated and completed in 1939. This building was appended to the Langley Free-Spinning Tunnel building (now Building 646), and provided a connection between the two facilities. 5. Alterations and Additions: The 12-Foot Low-Speed Tunnel has undergone relatively few modifications since its time of construction and currently appears much as it did when first built. The most significant modification to the facility affecting its operation was the fixing of the test section in 1958. Prior to that date, the entire test section was vertically tiltable from a 15° decent to a 40° accent by hydraulic arms. In 1958 however; the test section was fixed in a horizontal position and the hydraulic system was disconnected. Some other changes that have occurred to the test section, likely at the time of its transition, include the removal of bubble window for the “pilot’s” viewing of the model, and the construction of a swinging model mount. Several other modifications have occurred to the wind tunnel over time for general maintenance or updating. This includes the replacement of the fan blades due to damage in 1946. The three original porthole style observation windows from the control room of the office and laboratory building into the tunnel structure were replaced with a larger band of rectangular window sashes at an unknown time. As to be expected, most of the lighting, cameras, computers, and other electrical equipment related to the operation of the wind tunnel also appear to have been replaced and modernized.


VDHR ID# 114-5313-0405 (Page 4)

The office and laboratory building has also been renovated and updated to keep up with ongoing use of the facility. On the exterior of the building, the windows and all sheathing have been replaced. Several interior spaces have been renovated as well, including the second floor offices and shops and the third floor control and observation room.

B. Historical Context: The National Advisory Committee for Aeronautics (NACA) was established on March 3, 1915, with the mission of supervising and directing the scientific study of the problems of flight, with a view to their practical solution. European aviation advances and the potential for U.S. involvement in the First World War had largely been responsible for the creation of the NACA, which was officially approved as a rider on the Naval Appropriations Act of 1916. The NACA was appropriated $53,580 for lab construction on August 29, 1916, but no funds were provided for purchasing or developing a laboratory site. Committee members were well aware of the Army's $300,000 appropriation for a flying field, and apparently saw it as their best opportunity for a laboratory location.1 The NACA initiated specific actions to establish a joint civil-military experimental field with the Army, and efforts to advance civil and military aviation coincided at a site eventually known as Langley Field, lying four miles north of Hampton, Virginia, on the flat lands facing the two branches of Back River, which opens out into the Chesapeake Bay.2 Work began slowly at Langley to plat streets, construct buildings, and grade two aircraft runways; however, the U.S. entry into World War I in 1917 brought about accelerated construction and increases in money as well as personnel. NACA requested a small plot be assigned to them for the construction of their experimental laboratory at Langley, "near the water front and preferably near the western end of the field".3 The space was provided to them unofficially, but the army did not want to make an official sanction until further into the planning and development process of Langley Field. When the war ended in 1918, Army airfield construction immediately came to a halt. Many bases across the country had been leased and were simply abandoned; however, Langley had been created before the war with the intention of providing an experimental flying field and proving ground for aircraft, and was therefore retained after the war to carry out its original intent.4 The NACA once again repeated their request to officially have their plot at Langley sanctioned to them, stating that the laboratory building had

1 Brown, Jerold E., Where Eagles Land: Planning and Development of U.S. Army Airfields, 1910-1941. Washington,

D.C.: Office of Air Force History, 1985: 60. 2 NASA History Program Office. Langley Research Center. 3 Hansen, James R. Engineer in Charge. The NASA History Series Scientific and Technical Information Office

National Aeronautics and Space Administration Washington, D.C., 1987: 11 4 Maurer Maurer, Aviation in the U.S. Army, 1919-1939. Washington, D.C.: Office of Air Force History, 1987: 109.


VDHR ID# 114-5313-0405 (Page 5)

already been completed and that construction of a wind tunnel for research was underway. It was therefore necessary to officially recognize their claim in order to avoid potential disputes with the Army. By this time, the Army Air Service had been reorganized and the NACA issue became entangled in the larger question of how post-war Army aviation would be structured. The Army believed there was no need at all for a separate organization to conduct experiments in aviation and aeronautics and claimed that such a division of control at Langley would become burdensome. The issue was resolved when acting Secretary of War Benedict Crowell approved a memorandum stating that the “portion of Langley Field known as Plot No. 16 be definitely set aside for use by the National-Advisory Committee for Aeronautics for their purposes in constructing laboratories or other utilities necessary in scientific research and experiments in the problems of flight." The issue of dual control was resolved by authorizing NACA to conduct its work independent of the Air Service, with the exception that NACA personnel would come under the control of the Post Commander in matters pertaining to discipline, fire, guard, police and sanitation. Despite the Army’s continued reservations, the NACA's laboratory was officially dedicated in conjunction with completion of its first wind tunnel on June 11, 1920. NACA's laboratory was officially named the Langley Memorial Aeronautical Laboratory (LMAL) in honor of Samuel Pierpont Langley, the "father of aviation." On January 15, 1921, legislation authorizing occupancy of quarters by LMAL personnel passed the Senate and was favorably reported to the House. Later that year, a new and more sympathetic Commanding Officer arrived at Langley Field, which greatly improved military-civilian relations. From this point on, the NACA’s researchers were finally able to conduct their work in earnest.5 When LMAL was officially dedicated in June 1920, the laboratory complex included three buildings. The “Research Laboratory” (Building 587), completed in 1918, which included administrative offices, drafting, machine/woodworking shops, photography and instrument labs, and a lunchroom on the second floor. The wind tunnel building (Building 580), completed in 1920, which housed Tunnel No. 1, and the third building, which was a temporary structure for the engine dynamometer lab equipment. LMAL was in full operation by April 1921 and the NACA hired Dr. Max Munk to direct its growing aeronautical research program. A German theoretical aerodynamicist from the Zeppelin Company, Munk had abilities as a theoretician and generalist which the

5 Victory, John, “The Langley Laboratory,” TMs (Rough Draft) [photocopy] citing Memorandum Griffith to

Victory, January 5, 1922 Langley Historical Archive, NASA Langley Research Center, Hampton, Virginia.


VDHR ID# 114-5313-0405 (Page 6)

Committee expected would enable him to draw conclusions from LMAL’s research.6 Munk soon set about designing the LMAL’s second wind tunnel to address the problem of “scale effect.” This phenomenon had posed a serious problem for wind tunnel research; it skewed research results and required correction to accurately simulate conditions encountered by an actual airplane in flight. In response, Munk designed and built the Variable Density Tunnel (VDT), which could vary air density “so that almost any model of reasonable size could be tested under conditions comparable to those encountered by a full-scale aircraft in flight”.7 Another problem that faced researchers as the evolution of flight continued was the dreaded tailspin. The international aeronautical engineering community knew very little about the primary factors that influenced the spin or the relative effectiveness of piloting methods to recover from spins. In the 1920s Langley’s staff conceived a testing technique that used catapult and/or hand-launched aircraft models dropped from the interior ceiling of an Army airship hangar at Langley which was about 105 feet high. After using the method to study spins, the Langley staff concluded that the catapult technique was excessively time consuming and resulted in frequent damage to the fragile models. Langley then constructed a 5-foot diameter vertical wind tunnel in Building 580 (previously the site of the first NACA wind tunnel) to provide for measurements of the aerodynamic loads on aircraft models during simulated spinning motions. The models were not in free-flight during the tests but were mounted to a balance that was driven in simulated spinning motions by an electric motor. Airflow in this early tunnel was vertically downward, and tests were directed at the aerodynamics encountered in the spin. Using the aerodynamic data in equations of motion, the staff attempted to predict spin behavior. Meanwhile, the British researchers at the Royal Aeronautical Establishment (RAE) in England had observed the disappointing NACA efforts with catapult-launched models and subsequently conceived the idea of a vertical wind tunnel to permit free-spinning tests of aircraft models. Such a technique was much more productive than either catapult launches or wind-tunnel aerodynamic measurements. Following initial trials with a small model of the free-spinning tunnel, the RAE constructed a 15-foot full-scale version of the tunnel and proceeded to conduct fundamental research on spinning and spin recovery. Learning of the success of the free-spinning tunnel in England, researchers and management at NACA-Langley proceeded to design and construct a similar 15-foot free-spinning tunnel in 1934 under the direction of Charles H. Zimmerman, the Chief of the

6 Roland, Alex, Model Research: The National Advisory Committee for Aeronautics, 1915-1958. Washington, D.C.:

National Aeronautics and Space Administration, 1985: 92. 7 Ibid


VDHR ID# 114-5313-0405 (Page 7)

Stability and Control Section. The construction site for the new tunnel was in its own facility (present-day Building 646) located next to the Langley Full Scale Tunnel. Research operations in the NACA 15-Foot Free-Spinning Tunnel began in 1935. The airflow in the 15-foot tunnel was vertically upward to simulate the downward descent velocity of an aircraft during spins. At the beginning of a typical test, the model was mounted with pro-spin controls on a launching spindle at the end of a long wooden rod held by a tunnel technician. A tunnel operator increased the vertical air speed until the air forces on the model equaled its weight. At this point, the model automatically disengaged from the spindle and continued to rotate in a spin as the airspeed was continuously adjusted to maintain the model’s position at eye level in the test section. The model’s control surfaces were moved from pro-spin settings to pre-determined anti-spin settings by a clockwork mechanism, and the rapidity of recovery from the spin was noted. After the test was completed, the tunnel airspeed was decreased and the model was allowed to settle into a large net at the bottom of the test section. The model was then recovered with a long- handled clamp and prepared for the next test. Realizing the benefit of conducting tests of models in free flight, Charles H. Zimmerman conceived and successfully developed another unique wind-tunnel apparatus to study the dynamic stability and control characteristics of an aircraft model in a free-flying condition. Initially, a 5-foot-diameter “proof-of-concept” wind tunnel was constructed and suspended from a yoke in the 15-foot free-spinning facility (Building 646) that permitted it to be rotated about a horizontal axis and tilted from the horizontal position to a nose-down orientation up to an angle of 25º. A tunnel operator stood at the side of the test section and controlled the tilt angle of the tunnel and the airspeed produced by a fan located at the right rear of the test section. His main function was to adjust the airspeed and tunnel angles so that the model remained stationary in the center of the tunnel during a test. The evaluation pilot was positioned at the rear of the tunnel where he could easily see the lateral motions of the model and provide inputs to the model’s controls via fine wires that were kept slack during the flight. In a typical free-flight test, the model was placed at the center of a takeoff platform and the elevator or model pitch control was manually adjusted to a desired setting. The tunnel angle was adjusted to the expected glide path of the unpowered model and the airspeed was slowly increased until the model rose from the platform and assumed a flying attitude. The tunnel operator and evaluation pilot coordinated their tasks to permit an assessment of the relative stability and responses of the model to control inputs. Initial testing in the 5-Foot Free-Flight Tunnel started in 1937 with very encouraging results, including the development of an automatic light-beam-control device to reduce crashes during the learning process. Following the success of the 5-Foot prototype wind tunnel, Zimmerman began to design and develop the larger permanent tunnel. This tunnel would consist of a 12-foot, octagonal test section. The tunnel was to be housed in a spherical shaped building located next to the 15-Foot Free-Spinning Tunnel facility.


VDHR ID# 114-5313-0405 (Page 8)

Because the facility’s shared similar testing apparatus and the proof of concept model was actually located inside the building for the 15-foot tunnel, the 12-foot tunnel and its control room were appended to the 15-foot tunnel building. Construction for the new tunnel was initiated in 1938 and it became operational in 1939. Following the completion of the 12-Foot Free-Flight Tunnel, the 5-Foot Proof of Concept Model in the facility next door was disassembled and removed. The closed-circuit free-flight tunnel initially operated with a tiltable (hydraulically-driven) test section in a two-operator mode similar to the prototype model. For about 20 years, highly successful studies of radical aircraft configurations were conducted, during which advancements in internal strain-gauge technology permitted not only free-flight evaluations but also measurements of the aerodynamic characteristics of free-flight models during conventional wind-tunnel tests.

In 1958, a slack in the post-war operational schedule of the Langley Full Scale Tunnel permitted exploratory free-flight tests to be conducted in its gigantic 30 by 60-foot test section, providing much more freedom and less risk during flight tests. In addition, the models could be much larger and more sophisticated than the simple balsa models used in the free-light tunnel. For these reasons, the free-flight technique was transferred to the larger wind tunnel. When the technique was transferred, the free-flight tunnel was converted for conventional force-test studies of aerodynamics and its test section was fixed in a horizontal attitude. At this point, the tunnel was renamed the 12-Foot Low-Speed Tunnel. The tunnel continued to be used for testing throughout the rest of the twentieth century and is in continuous use by NASA Langley today for static and dynamic force tests.


VDHR ID# 114-5313-0405 (Page 9)

Chronology 1937 5-Foot Proof of Concept Model Constructed in 15-Foot Free-Spinning

Facility (Building 646) 1938 Construction of full-size, 12-Foot Tunnel Commenced 1939 12-Foot Free-Flight Tunnel Complete and Becomes Operational 1958 Free-Flight Testing Transferred to the Full-Scale Tunnel 1958 Test Section Fixed in Horizontal Position and Tunnel Begins Use Only in

Force-Test Studies (Becomes Known as 12-Foot Low-Speed Tunnel) 1992 Control and Observation Room Renovated and Computer Systems

Upgraded 2010 Facility Set for Deactivation and Demolition


VDHR ID# 114-5313-0405 (Page 10)

PART II. STRUCTURAL/DESIGN INFORMATION

A. General Description: Site The 12-Foot Low-Speed Tunnel (Building 644) is located on the south side of Andrews Street just east of the intersection with Hunting Avenue, at 644 Andrews Street. It is part of compound of buildings and facilities that include it, as well as Building 646 (the former 15-Foot Free-Spinning Tunnel and currently the East Area Compressor Building) and Building 645 (the 20-Foot Spin Tunnel) along with its associated office building (Building 645A). The 12-foot tunnel is located between Buildings 645 and 646, abutting and connected to the east side of Building 646, the earlier 15-Foot Free Spinning Tunnel Facility. This compound is set back from Andrews Street with a row of parking along the north side of the buildings. This is roughly the eastern terminus of Andrews Street, and the road is essentially a parking lot at this point, rather than a formal delineated street, which ends at Hunting Avenue, just to the west. To the east of the compound of facilities is a gravel extension of Andrews Street that doglegs around the side of Building 645. Beyond Andrews Street to the east is a narrow grassy area and the Back River. To the west side of the compound is Hunting Avenue, which divides it from Building 647, the East Shop Building and former wind tunnel facility, on the adjacent block. To the rear of the compound is a large open gravel covered area that until 2010 was the site of the Full-Scale Tunnel (now demolished). The laboratory and office portion of the 12-Foot Low-Speed Tunnel is the portion of the facility that actually adjoins Building 646 and is appended to its west side. The spherical tunnel housing portion of the facility is set to the east of the office building and is connected to the office building through a cylindrical bulkhead at the ground-level and through a projecting rectangular extension of the building at the third-floor level. The spherical structure is set within a chain-link fence enclosure that encapsulates it as well as assorted other support machinery, vacuum tubes, and pipework to the rear. Office and Laboratory Building Exterior The office and laboratory portion of the 12-Foot Low-Speed Tunnel is a rectangular, three-story, metal building which measures roughly 24’ wide by 34’ deep, occupying roughly 833 square-feet of ground area; however, it is appended to the much larger Building 646 giving the overall structure an L-shaped footprint. The 12-Foot office and laboratory building has a steel frame structural system clad with raised-seam steel panels. The building is set on a raised poured-concrete foundation and is topped by a shallow-pitched gable roof clad with raised-seam steel panels. The front façade of the building is


VDHR ID# 114-5313-0405 (Page 11)

on the north side that extends four bays out from Building 646 to which it is attached, the primary entrance to the building is actually in the easternmost bay of Building 646. This entrance consists of a single metal door with a fixed pane light. It is sheltered by a narrow shed roof supported by simple iron posts integrated into a metal railing that lines a concrete stoop at the foot of the door. This stoop is approached by a flight of five poured concrete steps. The front façade of the 12-Foot Low-Speed Tunnel office building is similar in composition to Building 646, which it is attached to, clad with raised-seam metal panels and integrated windows, however, the scale and fenestration pattern differs due to the interior layout. Each of the three stories on the front of the 12-Foot Low-Speed Tunnel office building are delineated by nearly full-width bands of continuous windows. Each band is composed of four awning-type windows with larger fixed panes over a smaller operable awning pane. The middle two windows on each floor have window-unit air conditioners installed in their lower sash. The rear façade of the building is identical to the front. The east side of the laboratory and office building has several connections to the associated spherical wind tunnel structure. A roughly 10’ diameter tubular bulkhead projects out from the first floor of the building and extends into the lower hemisphere of the wind tunnel housing. Additionally, the entire third floor of the building extends outward and connects to the upper hemisphere of the wind tunnel housing. The building is devoid of any embellishment or ornamentation and nearly all of the exterior cladding is nonoriginal. Construction records show that originally the building was clad with a tighter corduroy pattern corrugated Careystone (asbestos) panels. The windows were originally industrial style casement windows. Besides these aesthetic modifications however; the overall shape and configuration of the building remains intact and unchanged. Office and Laboratory Building Interior The interior of the 12-Foot Low-Speed Tunnel office and laboratory building is divided into office space, workshop area, and an observation/control room. The main entrance to the building is actually located on the adjacent Building 646 and leads into a central lobby area. A doorway on the left leads into a central hallway on the first floor of the 12-Foot Tunnel building. To the left of this hallway along the front of the building are two storage rooms. On the right side of the hallway along the rear of the building is an office and breakroom. At the end of the central hallway is a metal bulkhead and airlock that provides access into the interior of the spherical wind tunnel housing structure. This floor has older finishes and what seem to be some original features. The flooring throughout is covered with 12-inch vinyl tiles and the walls are painted pressboard. The ceiling consists


VDHR ID# 114-5313-0405 (Page 12)

of the exposed truss system that doubles as the support for the floor above. The door frames are simple metal architraves and the doors themselves are paneled wood with glass lights. The window frames in the rooms are wood with bull-nosed sills. All lighting and electrical work throughout the floor have exposed conduit. The second floor is accessed from a stairwell in Building 646 that goes up from the central lobby. A doorway from a landing in this stairwell leads into the 12-Foot Tunnel building, where another half-flight of stairs leads up to the second floor. This floor consists of three rooms that function as workshop and storage space. These spaces have been remodeled with new finishes. The floors are carpeted and the walls are covered with drywall. The third floor of the 12-foot tunnel building is also accessed from the stairwell in the Building 646. At the top of this stairwell is a doorway to the left that leads into the single room occupying the third floor of the laboratory and office building. This room functions as the observation and control room for testing in the wind tunnel. It was completely remodeled and updated in 1992. The floors are carpeted and the walls are covered with drywall. The ceiling is clad with an acoustic drop-tile system interspersed with fluorescent lights. The window surrounds are the original wood frames. A large central area in the room is raised up roughly one-foot and enclosed with simple metal railings. This area contains all of the work-stations, computers, and control panels for operating the wind tunnel. The test section of the wind tunnel is visible from this area, through a horizontal band of rectangular windows piercing the wall between it and the spherical wind tunnel housing. These windows replaced the original set of three smaller porthole style windows at an unknown date. A single doorway beside the raised floor leads onto a catwalk system inside the wind tunnel structure. Wind Tunnel Structure The spherical wind tunnel housing structure is located to the east of the office and laboratory building connected at the ground level by a tubular bulkhead and at the third floor through a full-width projecting bay. This large spherical structure measures approximately 60-feet in diameter and is set upon four steel bents on poured concrete footings just above ground level. The entire mass of the structure covers a ground area of 2,827 square feet. The structure has a frameless design, instead utilizing the sheathing as a unibody form. The sheathing consists of 3/8” steel panels welded together and the inside surface is covered with 2-inch thick rock wool insulation. The interior of the tunnel is accessed from the first floor bulkhead and the third floor of the office and laboratory building. Mounted centrally inside the sphere on a welded steel frame connected to the base is the large test section unit. Surrounding the test section is a


VDHR ID# 114-5313-0405 (Page 13)

system of catwalks that provides access to all sides of the test unit from the bulkhead at ground level, as well as the doorway from the third floor observation and control room. The test section unit is a self-contained system that incorporates the test cell, the wind screen, motor and fan blade, and all associated mechanical equipment. The test unit is accessed from a short stairwell off the catwalk leading into the left (north) side of the unit. Inside the unit, the first room accessed is the small former “pilot’s” chamber, where the person controlling the flight of the model stood. Originally, a bubble window projected into the test cell allowing the controller to see the model in flight; however, this window has been removed and covered with a sold surface. From the pilot’s chamber, three steps leads up into the navigation control room for the unit. This area is where the navigation controller stood and controlled the speed of the air flow as well as the tilt of the unit. This room has assorted controls, computers, and cameras, as well as a row of observation windows and a door into the test cell. The octagonal-profiled test cell is lined with plywood siding interspersed with panels of fluorescent lights on the upper and lower angled walls. Mounted centrally on the floor is a pivoting metal arm to which models can be connected for testing. Attached to this model mount is a camera and various sensors. The front (east) end of the test cell is lined with a mesh screen that evens airflow into the cell. At the rear (west) end of the cell is the large fan and motor that powers the wind tunnel. It is mounted on a metal frame that connects to the side walls and ceiling of the unit. The eight-sided test cell transitions into a roughly comparable size tubular opening in which the six-bladed wood completely fills.

1. Character: The 12-Foot Low-Speed Tunnel has a unique character that is reflective of its specialized function. The office and laboratory building is nondescript and does not stand out, although it is atypical to other facilities at NASA that incorporate a brick façade with minimal classical influences. Instead, it is a steel frame building clad with corrugated metal that blends into the 15-Foot Spin Tunnel Building (Building 646) to which it is attached. The unique and character-defining aspect of the 12-Foot Low Speed Tunnel is the tunnel housing structure. This 60-foot diameter spherical structure is the not the largest wind tunnel structure at NASA LaRC; however, it is the only example with a spherical-shaped body. This permitted the test section inside the structure to be tilted while retaining an even air flow to the model in free-flight. The test section has now been fixed in a horizontal position as free-flight tests are no longer conducted here; however, its design is representative of the by-gone-days of research being performed in specialized wind tunnels and is an important aspect of the early development of research facilities at NASA LaRC. 2. Condition of Fabric: Overall, the 12-Foot Low-Speed Tunnel facility remains in a good condition, and continues to be used in testing applications. The office


VDHR ID# 114-5313-0405 (Page 14)

and laboratory building have been renovated with new windows and exterior sheathing in the recent past. Interior spaces such as the shop and storage areas, as well as the control and observation room have also been upgraded and renovated. The wind tunnel housing and test section have also been maintained in remain in good and operable condition. The exterior has been painted and exhibits only minor rust and surface impairments. Moisture, mostly from condensation, appears to be a threat to the inside of the wind tunnel housing as can be seen from puddling at the bottom and from surface rust on the catwalk system. The test section, control equipment, fan and motor, and all other associated equipment appear to be maintained and in good working order.

B. Construction: The construction methods used at the 12-Foot Low-Speed Tunnel are reflective of the specialized research that was carried out at the facility. The office and laboratory building is relatively simple construction with a simply steel frame system and clad with metal sheathing. It is topped by a low-pitch gable roof and has rows of industrial style windows. The interior rooms of the building are furnished according to the uses of those spaces. The majority of the first floor serves as storage and breakroom space and therefore is simply finished. These spaces are no longer used and subsequently have not been updated or renovated. The second and third floor continued to be used and therefore have been continually updated with modern finishes. The third floor contains the control and observation room and therefore houses a variety of high-tech computers and control panels for operating the wind tunnel. The wind tunnel structure itself has a much more complex design to accommodate its specialized function. The housing is 60-foot sphere constructed of welded steel panels strong enough to contain the high wind speeds and air pressure during tests. The spherical shape is intentional and critical to the original testing that was carried out in the tunnel. The tunnel apparatus including the fan and test section are mounted centrally on a steel frame and pivotable to mimic the accent or decent of an aircraft in flight. The spherical shape of the wind tunnel housing ensures that there is equal air flow throughout the structure and can enter the test section consistently at any angle of flight selected for study.


VDHR ID# 114-5313-0405 (Page 15)

C. Mechanicals/Operation: The 12-Foot Free Flight Tunnel was a simple, open-return tunnel of octagonal cross section. The test section measured 12-feet wide at the throat and was 15-feet long. The overall length of the assembly including the throat, test section, screens, and fan housing was 32-feet long. The tunnel is arranged so that its longitudinal axis, and thus the air stream, may be inclined at different angles to the horizontal. A hydraulic jack provides control over the tunnel angle. Suitable guide vanes and screens are installed in the entrance cone of the tunnel to insure uniform air-flow distribution. The housing is spherical; therefore the relation of the tunnel to the wall does not vary with tunnel angle. The tunnel is equipped with a-voltage control for the propeller-drive motor that provides an extremely flexible air-speed regulation. The drive consists of a 600-horsepower electric motor turning a 15-1/2 foot diameter propeller. A tunnel operator stationed at the side of the tunnel test chamber adjusts the air speed in the tunnel to the speed of the model and accommodates the tunnel angle to the flight-path angle of the model. The operator thus controls the longitudinal and the vertical location of the model in the tunnel. This operator also controls the power input to the model for powered flight. The direction of flight of the model or the lateral position of the model in the tunnel is controlled by a "pilot" who operates the normal airplane control surfaces by means of electromagnetic mechanisms in the model. The power is supplied to these mechanisms, as well as to the model propeller-drive motor, through a light flexible cable that trails behind the model. The pilot is the principal observer because he has control of the model and can detect deficiencies in stability or control. The pilot's observations give a direct qualitative indication of the stability and control; records from three 35-millimeter moving-picture cameras mounted to photograph the motion of the model in three mutually perpendicular planes supply quantitative data on the stability characteristics of the model and its response to control displacements. Neon lamps in the common field of the three cameras indicate the control displacement. The tunnel may be operated at air speeds from 0 to 90-feet per second and can accommodate glide angles of 40° or climb angles of l5°. The tunnel can be supplied with air compressed up to two or more atmospheres in which the operators will work. A decompression chamber is provided so that the operators can return gradually to normal atmospheric pressure. For a typical test, the model rests on the floor with the wheels locked to prevent rolling and with the elevators set at the proper angle for the desired flight. Power is supplied to the model propeller and the air speed in the tunnel is slowly raised. The tail of the model rises and, when the estimated flight speed and flight power


VDHR ID# 114-5313-0405 (Page 16)

are reached, the pilot moves the elevator up momentarily to overcome the ground effect, and the model rises to the center of the tunnel. If the estimated air speed and power are correct for the particular elevator setting, little further adjustment is required for steady flight. The pilot then flies the model in the test section and notes the stability and the response to control movements. In order to minimize damage from crashed models, the floors and lower walls of the test section were lined with 2-inch thick sponge rubber. The models used in the 12-Foot Free-Flight Tunnel are generally roughly 1/12 scale; and had wing spans in the range from 3 to 4 feet and wing loadings from 2 to 4 lb/ft. Originally, they were constructed with solid balsa wings and hollow balsa fuselages, but later models had wings of built-up construction with spruce spars and had fuselages of much stronger construction. In some cases, the fuselage was built with plywood bulkheads supporting either a laminated balsa or fiberglass-plastic shell. In other cases, simplified fuselages for general research models consisted of an aluminum-alloy boom.8

8 Campbell, John. “Free and Semi-Free Model Flight-Testing Techniques Used in Low-Speed Studies of Dynamic

Stability and Control”. AGARDograph Journal Of The North Atlantic Treaty Organization Advisory Group For Aeronautical Research And Development. October 1963


VDHR ID# 114-5313-0405 (Page 17)

PART III. SOURCES OF INFORMATION A. Primary Sources

Campbell, John. “Free and Semi-Free Model Flight-Testing Techniques Used in Low-Speed

Studies of Dynamic Stability and Control”. AGARDograph Journal Of The North Atlantic Treaty Organization Advisory Group For Aeronautical Research And Development. October 1963.

NACA Tunnel Details and Costs Record. Free-Spinning Wind Tunnel, Free-Flight Tunnel, and

Connecting Buildings. June 30, 1942. NASA LaRC Archives. Available online at: http://crgis.ndc.nasa.gov/crgis/images/d/d9/1942-06-30_Low_Speed_Tunnel_Cost_and_Details.pdf

NASA. Cultural Resources, History, Archaeology, and GIS Website. Langley Research Center.

Available online at: http://crgis.ndc.nasa.gov/historic/644 NASA. “Langley Research Center.” NASA History Program Office. Available online at:

http://history.nasa.gov/centerhistories/langley.htm Victory, John, “The Langley Laboratory,” TMs (Rough Draft) [photocopy] citing Memorandum

Griffith to Victory, January 5, 1922 Langley Historical Archive, NASA Langley Research Center, Hampton, Virginia.

Shortal, Joseph A and Clayton J. Osterhout. Preliminary Stability and Control Tests in the NACA

Free-Flight Wind Tunnel and Correlation with Full-Scale Flight Tests. NACA Technical Note No. 810. NASA: Washington, D.C., June 1941.

B. Secondary Sources

Baals, Donald D. and William R. Corliss, Wind Tunnels of NASA. NASA: Washington, D.C.,

1981. Brown, Jerold E., Where Eagles Land: Planning and Development of U.S. Army Airfields, 1910-

1941. Washington, D.C.: Office of Air Force History, 1985, 60. Gray, George W., Frontiers of Flight: The Story of NACA Research. New York: Alfred A.

Knopf, 1948 Hansen, James R. Engineer in Charge: A History of the Langley Aeronautical Laboratory, 1917-

1958. The NASA History Series Scientific and Technical Information Office National Aeronautics and Space Administration Washington, D.C., 1987


VDHR ID# 114-5313-0405 (Page 18)

Maurer Maurer, Aviation in the U.S. Army, 1919-1939. Washington, D.C.: Office of Air Force

History, 1987, 109. Roland, Alex, Model Research: The National Advisory Committee for Aeronautics, 1915-1958.

Washington, D.C.: National Aeronautics and Space Administration, 1985.


VDHR ID# 114-5313-0405 (Page 19)

LOCATION MAP

Date Drawn: June 18, 2013 Drawn By: Robert J. Taylor, Jr.

NASA LANGLEY RESEARCH CENTER 12-FOOT LOW-SPEED TUNNEL (Building 644) 644 Andrews Street NASA Langley Research Center, Hampton, Virginia



VDHR ID# 114-5313-0405 (Page 20)

FLOOR PLAN SKETCH

Reduced Copy of NASA LaRC Real Property Floor Plans

NASA LANGLEY RESEARCH CENTER 12-FOOT LOW-SPEED TUNNEL (Building 644) 644 Andrews Street NASA Langley Research Center, Hampton, Virginia

SCALE 10 0 10 20 30

HISTORIC STRUCTURES REPORT

INDEX TO PHOTOGRAPHS NASA LANGLEY RESEARCH CENTER, VDHR ID# 114-5313-0405 12-FOOT LOW-SPEED TUNNEL (12-Foot Free-Flight Tunnel; Building 644) 644 Andrews Street NASA Langley Research Center Hampton Virginia Robert J. Taylor, Jr., Photographer April 2013 PHOTO 1 VIEW OF OVERALL FACILITY, FACING SOUTH PHOTO 2 VIEW OF REAR OF OFFICE AND LABORATORY BUILDING,

FACING NORTHWEST PHOTO 3 VIEW OF OBSERVATION AND CONTROL ROOM, FACING EAST PHOTO 4 VIEW OF BULKHEAD ENTRANCE TO TUNNEL, FACING EAST PHOTO 5 VIEW OF TUNNEL TEST SECTION AND FAN, FACING

SOUTHEAST PHOTO 6 DETAIL OF MODEL ARM INSIDE TEST SECTION, FACING WEST PHOTO 7 Photocopy of Photograph (Original in Langley Research Center Archives,

Hampton, VA [LaRC] (NACA 15768) Photographer Unknown, Date July 26, 1938.VIEW OF PROTOTYPE FREE-FLIGHT TUNNEL.

PHOTO 8 Photocopy of Photograph (Original in Langley Research Center Archives,

Hampton, VA [LaRC] (NACA 15838) Photographer Unknown, Date August 5, 1938. VIEW OF TUNNEL UNDER CONSTRUCTION, FACING SOUTHEAST

PHOTO 9 Photocopy of Photograph (Original in Langley Research Center Archives,

Hampton, VA [LaRC] (NACA 16627) Photographer Unknown, Date January 6, 1939. TUNNEL CONSTRUCTION COMPLETED, FACING SOUTHEAST

PHOTO 10 Photocopy of Drawing (Original in Langley Research Center Archives,

Hampton, VA [LaRC] Drawn By Unknown, Date Unknown. CUTAWAY DIAGRAM OF THE 12-FOOT LOW SPEED TUNNEL

http://crgis.ndc.nasa.gov/historic/12-Foot_Low_Speed_Tunnel


See Index to Photographs for Caption VDHR # 114-5313-0405 (Photo 1)

report > historic structures report 12-foot low-speed ... · air-distribution was possible....

Documents