30 X 60 Full Scale Tunnel
|Center:||Langley Research Center|
|Historic Eligibility:||National Historic Landmark|
|Important Tests:||Brewster F2A-2 Buffalo, British P.1127 Fighter, Project Mercury|
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Commonly referred to as the Full Scale Tunnel, Building 643 in the NASA East Area has been the site of four historically significant activities since its construction in 1930. These activities have spanned from the era of biplanes to NASA space programs. The following provides information on research activities in some of the most important programs conducted in Building 643.
Full Scale Tunnel was demolished in 2011 after many years of continuous use. (See Tribute) Artifacts from this National Historic Landmark were salvaged for displays, including the Smithsonian's Milestones of Flight exhibit. See Artifacts for a listing of salvaged items.
[top] Full-Scale Wind Tunnel
After the Variable Density Tunnel (VDT) of the National Advisory Committee for Aeronautics (NACA) was put into operation in the 1920s, it was recognized as a breakthrough accomplishment in wind-tunnel testing technology. By using higher than atmospheric pressure in its airstream, the VDT provided aerodynamic conditions more representative of those experienced in flight. However, the relatively small size of its test section required the use of relatively small aircraft models and severely limited testing of full-scale airplane components. Powered models could not be accommodated, and the aerodynamic effects of real aircraft construction such as rivets, fabric, and other component details were difficult or impossible to simulate. Of even more concern, however, was the recognition that significant aerodynamic turbulence was present in the tunnel air flow due to the geometrical shape of the VDT. As the concern over results from the VDT began to grow, several research leaders at Langley began to advocate for a new large wind tunnel capable of conducting tests of full-scale aircraft at that time.
The NACA authorized the construction of the Full-Scale Tunnel (FST) at Langley in February 1929 and design work started immediately. Smith J. DeFrance led the design team, which also included Abraham Silverstein, Clinton H. Dearborn, and Harry J. Goett. Significantly, three of these NACA researchers later became Directors of NACA or NASA field centers: DeFrance (Ames), Silverstein (Lewis), and Goett (Goddard). The timing of the Full-Scale Tunnel project was fortunate: the initial appropriation of $900,000 was made before the onset of the Depression; and by the time work began in the spring of 1930, labor and material costs had fallen, and the project directors could draw from a large pool of unemployed engineers.
Since the FST was to be the first wind tunnel constructed with an elliptic throat and two drive propellers mounted side-by-side, the designers requested that a 1/15-scale model of the FST be constructed for studies of the flow circuit and guidance in the shaping of the tunnel lines and airflow turning. The request was approved, but it was noted that the NACA did not have sufficient shop space for construction of the model tunnel. Instead, management suggested that the model be built outdoors with a protective roof. Construction of the wooden model tunnel proceeded in a vacant area between two NACA power plant buildings behind the NACA administration building in 1929 using a lumber framework and a tarpaulin-covered roof. After a highly successful test program which provided vital design information, the model tunnel was moved to the FST building after the full-scale article was constructed.
The model tunnel was subsequently used at the FST for years as a small-scale test facility, including valuable studies of the propeller-whirl flutter instability that caused fatal accidents of two Electra turboprop transports in the 1950s. The model tunnel was subsequently given to Portugal in the late 1950s by NASA Headquarters for use in its scientific programs as part of good will within the AGARD cooperative program.
In the 1970s Langley conducted a major inspection and rehab of the FST uncovering alarming fatigue cracks and evidence of major vibratory issues within the mounting structures of both drive motors. The non-symmetric airflow in the tunnel (both propellers rotated in the same direction) was identified as a major factor causing the problem, and Langley requested that NASA Headquarters attempt to have the model tunnel returned to Langley for additional studies of altering the flow properties in the FST. However, return of the tunnel was resisted (the problem actually was discussed at levels as high as the Secretary of State Henry Kissinger) and the tunnel remained in Portugal. NASA proceeded to have a second model tunnel constructed under contract in Canada, and that tunnel was located in the hangar annex of the FST and used to evaluate many structural modifications to mitigate the flow-induced structural problems. Several modifications to the FST came from the model investigation including large guide vanes located around the periphery of the inlet of the tunnel exit cone.
Work on the FST proceeded rapidly, and it was completed and ready for operation in May 1931, when it was the NACA centerpiece of the Sixth Annual Aircraft Engineering Conference. The largest wind tunnel in the world at that time, the FST had a unique design, with the building’s steel framework visible on the exterior of the building. The enormous facility measured 434 feet in length, 222 feet in width, and 97 feet in height, and immediately became a recognizable landmark at Langley. The semi-elliptical test section measured 30 feet high by 60 feet wide with an open jet (that is, no walls immediately adjacent to the test section) and allowed the installation of aircraft with wingspans up to 40 feet. The tunnel was powered by two 35 feet 5 inch diameter propellers, each driven by a 4,000-horsepower electric motor, which could circulate air through the test section at speeds between 25 and 118 mph. The air circuit was of the double-return type, in which the airflow from the propellers was split right and left into two streams, doubling back between the test section and the building’s walls, then reuniting before entering the throat of the test section. Extensive tuning of airfoil-shaped turning vanes in the tunnel circuit resulted in satisfactory flow properties in the test section. In addition to testing full-scale aircraft the FST had considerably lower turbulence than the VDT.
Full-scale aircraft were mounted to a 6-component strut support system which used linkages connected to dial-type force scales to measure air loads on the test subject. Early calibrations were conducted with aircraft that also underwent flight tests permitting correlation with FST results. After successful initial operations, the tunnel became a national asset for testing and its contributions to aeronautics and space research continued for 78 years.
Early testing in the FST focused on the aerodynamic effects of aircraft geometry and construction methods on aerodynamic drag and engine cooling. Results of exploratory testing indicated unexpectedly high performance penalties from seemingly negligible aircraft protrusions and construction methods. Aware of the value of such tests, in 1938 the Navy sent its Brewster F2A-2 Buffalo to Langley for analysis of the aircraft’s aerodynamic performance which had resulted in a disappointing top speed of only 250 mph. After a number of drag-producing items such as the landing gear, exhaust stacks, gun installations, and other details were analyzed, recommendations for modifications to the design were made by the FST staff that were subsequently adopted and resulted in a 31-mph increase in top speed. The tests were such a success that both the Navy and the Army quickly sent a steady stream of military aircraft to Langley for “drag cleanup tests.” In the next 18 months, 18 different aircraft were tested and improved in the FST. The FST operated around the clock, seven days a week, during WWII conducting not only drag cleanup tests, but engine cooling methods, stability and control, and unexpected operational problems. Early versions of virtually every high-performance fighter aircraft were evaluated in the FST, allowing for countless design improvements that gave American pilots a critical edge in combat.
Following WWII, the FST was used in the 1950s to explore emerging new concepts such as wing sweep, delta wings, and boundary-layer control for improved low-speed performance. A remarkable variety of other subjects were also tested in the FST, including dirigibles, submarines, radar antennae, gliding parachutes, inflatable airplanes, and even another wind tunnel complex.
Although the performance of jet aircraft in the postwar period outpaced the relatively low speed capabilities of the FST, the facility remained an important test facility for NACA and its successor, the National Aeronautics and Space Administration (NASA). After the creation of NASA, changes in the tunnel’s backlog of tests and transfer of key NACA personnel to the new NASA Space Task Group (STG) preparing for Project Mercury provided an opportunity for a new type of testing—remotely-controlled free-flying models. These tests had previously been conducted in the Langley 12 Foot Free-Flight Tunnel to determine the flight characteristics of radical aircraft designs, but the availability of the FST and its huge test section was perfect for the flight models by providing much more room to maneuver the model as well as use larger models with more realism.
The influx of free-flight models brought a decade of intense research on unconventional vertical takeoff and landing (VTOL) aircraft. Numerous types of civil and military VTOL designs were tested, including the British P.1127 fighter which ultimately led to the current Marine Corps Harrier jump-jet.
In the 1960s new types of aerospace projects were conducted to evaluate the low-speed characteristics of a parawing/capsule combination, advanced supersonic transports, lifting body configurations for spacecraft, and breakthrough concepts such as variable sweep. The tunnel was also used to test the tubular Lunar Landing Training Vehicle to assist in an investigation of the cause of an accident during the training of astronauts in late 1968.
In 1969, the FST began a research program on high-angle-of-attack behavior of fighter aircraft using free-flight models. The program began an integral part of the development process for all new military high-performance aircraft for over 25 years. An upgrade to the FST in 1977 (and later in 1984) improved the operation of the electric fan motors, and allowed the facility to continue testing aircraft designs whose technology and performance could not possibly have been envisioned in the biplane era in which it was built.
The historical significance of the FST and its many contributions to aerospace technology were recognized when it was designated a National Historic Landmark in 1985. The oldest operating wind tunnel at Langley when NASA finally decommissioned it in October 1995, the facility gained a new lease on life when it was transferred to Old Dominion University (ODU) under the terms of an innovative privatization program. ODU began operations at the FST in October 1996, providing engineering research facilities for graduate students and private customers in the field of aircraft and automotive transportation.
[top] First Langley Gust Tunnel
Although NASA Langley’s Building 643 is normally associated with the Full-Scale Tunnel operations, it has also been the site of other significant research projects. For example, in the 1930s and 1940sthe facility was the site for an innovative NACA testing technique to acquire data for the structural design of aircraft. A daunting engineering design challenge in aviation is the development and validation of methods to predict air loads experienced during flight in gusts and turbulence. This capability is extremely important, not only from a safety-of-flight perspective, but also to prevent an over design of aircraft structures which would result in unnecessarily large weight penalties. Early research in the 1920s and 1930s at the NACA Langley laboratory had included theoretical studies of loads generated in specific gust fields, but flight data to substantiate the predictions were extremely difficult to obtain at that time.
In order to experimentally investigate gust loads under controlled conditions, the NACA designed and constructed a pilot gust tunnel in 1937 within an area of the Langley Full-Scale Tunnel (Building 643) building outside the tunnel flow circuit. Its location was under and to the right of the exit cone structure of the FST. (See document entitled "1942-Use of Full Scale Wind Tunnel" at this site for the location of the Gust Tunnel in 1942).
The pilot gust-tunnel testing technique consisted of launching dynamically scaled, free-flight airplane models through gusts of known shapes and intensities. During the flight, measurements were made of the accelerations and reactions of the models due to the gusts. The test facility consisted of a gust generator, a catapult for launching the models, and two screens used to decelerate and catch the airplane model at the end of the flight. The gust generator was a large squirrel-cage blower which supplied air to an expanding rectangular channel discharging a current of air upward. The vertical jet of air was 6-ft wide and 8-ft long and its air speed profile was shaped by a combination of screen meshes designed to produce the desired gust shape. After the catapulted airplane model completed its flight through the vertical-gust field, it impacted a barrier of vertical rubber strands which decelerated the model. After deceleration, the model nose (shaped like a barbed hook) engaged a burlap screen which stopped the model and held it until the model was removed by the tunnel operator. The propelling catapult was powered by a dropping weight, and the maximum model flight speed was adjustable by changing the amount of weight. The facility was capable of testing scaled airplane models having wings of about 3-ft span at speeds up to about 50 mph.
This first gust-tunnel facility operated in Building 643 for almost a decade. The tunnel produced very valuable information on gust loads as affected by primary aircraft design variables, and results from the facility were used to justify reducing the structural design criteria that had led to over design of wing structures for certain types of aircraft configurations.
In 1945 the pilot gust tunnel was replaced by a new Langley Gust Tunnel which was similar in operational concept, but capable of testing larger 6-ft-span models at speeds up to 100 mph. The facility was housed in a new building (Building 1218) in the Langley West Area. The blower from the pilot tunnel was retained and briefly used at Building 643 for studies of flow through helicopter blades in hovering flight.
See an early video of these tests.
[top] Propulsion Noise Laboratory
Another important historical research operation in Building 643 was a sound laboratory used in studies of the generation and suppression of propeller noise. The sound lab was located in the front of the building on the right near the staff offices. (See document entitled "1942-Use of Full Scale Wind Tunnel" at this site for the location of the Sound Lab in 1942). The lab combined experimental and theoretical analysis of propulsion noise and was involved in research on how to suppress noise generated by propeller-driven aircraft. Noise generators were used to simulate various levels and tones of noise during typical studies and virtually all testing was done outside the FST test section or wind-tunnel operation.
The most famous project conducted by the sound lab group was the highly successful modification of a propeller-driven military liaison-type aircraft (Stinson L-5) in the late 1940s. During that time the rapid post-war expansion of interest in personal-owner aircraft stimulated the NACA to develop methods to reduce the noise of airplanes. In the opinion of regulatory agencies, the threat of excessive noise from propeller aircraft was one of the most significant threats to the growth of civil aviation.Theories had been developed for the prediction of propeller noise in the late 1930s, but the NACA focused on an effort to reduce noise from all sources—propeller, engine, and exhaust system. A coordinated effort among several Langley organizations to demonstrate the ability of technology to reduce the noise of a typical personal-owner aircraft was conceived and included the sound lab contingent from the FST.
A five-bladed propeller was chosen for the experiment so as to reduce the required tip speed of the propeller blades, thereby reducing propeller-generated noise. Existing muffler design methods for aircraft were inadequate, forcing the FST staff to conduct experiments to arrive at a suitable muffler for the experiment. With propeller, engine, and muffler modifications, the noise pressure levels of the airplane were reduced an astounding 90 percent.
The modified airplane was flown and demonstrated as a “quiet airplane” at the Sixteenth Annual Inspection at Langley in May 1947. Many in attendance did hear the airplane as it flew over the assembled crowd at an altitude of a few hundred feet during a break at the inspection. Following the demonstration, additional flights generated detailed engineering data on noise levels for the basic and modified airplane.
Reports, documents, photographs, and video of the "Quiet Airplane Project" are included with the "Aircraft Noise Reduction Facility."
[top] Procedures Trainer for Project Mercury
Yet another research activity in Building 643 produced critical contributions to the U.S. aerospace program in the late 1950s and early 1960s for the embryonic NASA space program. As the U.S. raced to meet the Russian challenge of Sputnik, leading Langley managers and researchers realized how ignorant they were of space and rocket technologies. The massive education process included developing basic understandings of celestial flight, meeting the challenges of designing a rocket/capsule configuration that would be reliable and safe, and developing technical and political means to communicate, track, and recover astronauts after space missions.
When Langley’s Christopher C. Kraft was assigned the incredibly difficult job of organizing and directing the flight operations for the nation’s first manned space flights in Project Mercury in the late 1950s, he quickly recognized the special challenges facing his team within the NASA Space Task Group (STG) in the areas of procedures and communication. Kraft conceived the idea for flight procedures trainers that could be tied into a central command center and provide realistic training for routine and emergency operations for astronauts, controllers, and the tracking station personnel. Under NASA contracts to McDonnell, two Mercury procedures trainers were built by the Link Trainer Company, which was famous for building airplane trainers for pilots in WWII. One of the procedures trainers was installed at the Cape and the second was located in Building 643 at Langley.
A photograph of the Langley procedures trainer showing astronaut John Glenn in the capsule simulator and NASA engineer Charles Olasky at the computer console appears in the collection of photographs at this site.
A special enclosed room was built beneath the exit cone flooring of the Full-Scale Tunnel (under the tunnel air circuit) to house Mercury Procedures Trainer No. 1 which consisted of a complete mock up of the Mercury capsule with operating instruments and controls interconnected to an analog computer. The trainer provided practice in sequence monitoring and familiarization with the cockpit systems. External reference through the capsule’s periscope was simulated by means of a cathode-ray tube display; and provision was included for pressurizing the astronaut’s suit and for simulating heat and noise. Also included in the same room, for the equally essential training of the personnel who would man the 17 Mercury tracking stations across the world, were three ground-control consoles (for doctor, spacecraft communicator and systems monitor) which formed the minimum equipment at any one of the tracking stations.
By simulating the entire mission, the fledgling team could interact during training sessions, which were held dozens of times a day in the build up for manned missions. Virtually all the original seven astronauts used the Langley procedures trainer. With the use of the trainers, the STG team built up the procedural elements during Mercury-Redstone and Mercury-Atlas missions that would become the backbone of future NASA manned space activities. The Mercury astronauts who flew the suborbital missions claimed that the most useful pre-flight training for normal and abnormal conditions was obtained in the trainer.
Mercury Procedures Trainer No. 1, re-designated the Mercury Simulator, was moved from Building 643 at Langley to a Manned Spacecraft Center building at Ellington AFB, Houston, Texas on July 23, 1962. The room that had been occupied by the trainer then became a model preparation room for tests in the Full-Scale Tunnel.
[top] Facility Closure and Demolition
The Full Scale Tunnel performed its last test on September 4, 2009. NASA made the difficult decision to close and demolish the facility several years prior, citing deterioration of the structural integrity of the tunnel, lack of funding for repair and maintenance, and no current or future mission need for its testing capabilities. The building was demolished in 2010. See Salvage List.
[top] Damage and Repairs
[top] Models in Model Tunnel
These models were tested in the model of the Full-Scale Tunnel.
The SST model was tested to determine wall effects before a large scale model of the same configuration was tested in the actual Full-Scale Tunnel. The reference for the SST test is: Low-Speed Wind-Tunnel Tests of 1/9-Scale Model of a Variable-Sweep Supersonic Cruise Aircraft.
[top] Personnel and Awards
[top] Group Photos/Social Events
Annual Engineering Conferences
[top] Other 643 Facilities
[top] InterviewsJoe Chambers
June 9, 2010 Sam Katzoff
Dr. Katzoff came to NACA after finishing his degree at Johns Hopkins in chemical engineering. It was March 1936 and the country was in the Great Depression. When asked what is like coming to NACA, he responded, "Jobs were hard to get. I was assigned to aerodynamics and had no training, but I was a smart kid." He went on to explain that groups of new employees, mostly engineers just out of college, started together and most were assigned to the lab at Full Scale. Following retirement in 1974 as chief scientist, Dr. Sam tutored children and wrote teaching manuals. Sam Katzoff, who spent more than three decades years at NASA Langley, and whose book "Clarity in Technical Writing" is still regarded as gospel by those at the center who write reports, died September 25th, 2010 at a retirement community in Pikesville, Md. He was 101.
"I came to work for NACA in 1949 and they put me in the Full Scale Research Division. I worked in the 30x60 foot tunnel for 12 years...By time I got done working there, I knew everything about that tunnel. We tested submarine models, blimp models and several full-size airplanes. We tested a vertical take-off and landing, live with the engines running. That’s the way things were...At lunchtime, we could go to the return passage and we would play softball. The test chamber was very large. We’d hook the crane from the side to the back to the other hook to rubber bumpers and ride in that thing and work on models up there 60 feet above the ground. We called it ‘Annie.’..The models sat on a big platform, a big steel frame with seven big Toledo scales. We’d set the model at a certain angle and the tunnel as a certain speed. Then the scales printed a tape. Those tapes were folded up and given to the computers. It would take them hours to punch all of the data. The head mechanic then was Joe Walker. He and I got together and decided we could build a turntable up there…We went to the junkyard, found a great big ring gear, let the engineers do the design and we built it. That turntable is still there today. They call it 'Scallion’s folly.' I feel real good about having a hand in that."
From A Look Back with Langley's NACA Alumni: NACA's 95th Anniversary by Denise Lineberry.
February 9, 2010 Claude Patterson
Low-Speed Wind-Tunnel Tests of 1/9-Scale Model of a Variable-Sweep Supersonic Cruise Aircraft. 1977. H. Clyde McLenmore, Lysle P. Parlett, and William G. Sewall.
[top] Press Releases and Articles
1934 Air Leaders Meet Today In Research, Washington Post, May 23, 1934
1943 The Untold Story of Langley and a Famous Japanese Zero, Joe Chambers, 2010. (See also 1943 report on testing.)
FST and Tank No.1 Complete Quarter Century of Service, 1956 Air Scoop
Suggested Alternate Uses for FST from 1995 Air & Space Magazine
A Plane Crash in 1944 is Saving Lives Today, 2009 Daily Press Article
[top] Historic Documentation