Vortex Research Facility

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Facility 720B
Typical wake vortex test

Center: Langley Research Center
Location: Hampton, Virginia
Year Built: 1942
Historic Eligibility: National Register Eligible
Important Tests: Mercury and Gemini capsules, Wake Vortex Research

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[top] History

[top] Impact Dynamics Research Facility

In the late 1950s, NASA began using Tow Tank 2 for space capsule testing. The facility was renamed the Impact Dynamics Research Facility, and capsules from both the Mercury and Gemini programs were subjected to impacts on various surfaces including sand, land, and water. These tests eventually ended, and the tank was converted into the Vortex Research Facility.

[top] Vortex Research Facility

During routine landing operations at airports, the wings of aircraft shed vortices which resemble powerful horizontal tornadoes in their wake. The strength, duration, and intensity of the vortices are direct functions of the weight of the generating aircraft. For heavy transport aircraft, the vortices extend miles behind the aircraft and represent a significant threat to lighter aircraft flying through the vortex wake. In the late 1960s, large wide-body transport aircraft became operational and wake-vortex encounters and accidents began to occur. The Federal Aviation Administration became alarmed because aircraft separation distances in the landing pattern would have to be significantly increased to minimize the vortex threat. Increases in separation distance significantly delay the arrival and departure of incoming and outgoing flights, thereby causing airport saturation and flight delays. Therefore, in the early 1970s NASA initiated a broad study of the trailing vortex phenomenon to understand the flow physics of the problem, determine the magnitude of the threat to trailing aircraft, and evaluate the effectiveness of aircraft modifications that might alter the properties of the trailing vortices and minimize the problem. The NASA efforts included wind-tunnel tests in several facilities, aircraft flight tests, and experimentation in unique facilities.

The concept of using aircraft models propelled through an instrumented test section for wake vortex studies was proposed by Langley researchers, and an appropriate test facility was sought. In the 1960s NASA had closed its Tow Tank No. 2 (Building 720B) which had been used for performance evaluations of seaplane models towed in a water channel. The water had been drained from the facility and the basin had been filled with sand. Modifications to the tank facility resulted in the Langley Vortex Research Facility (VRF), which operated for over 10 years as a major element in the NASA program. The VRF building was 1,850 feet long and an instrumented automobile-type research vehicle (see email below regarding vehicle) was used to accelerate a model of a vortex-generating aircraft to a speed of approximately 100 ft/sec through a test section. The test section was covered to prevent the vehicle wake from interfering with the wake of the aircraft model. A slot in the ceiling of the test section permitted passage of a model support strut in the slot and was lined with brush-like material to block the flow of the propelling vehicle wake downwash. Conventional wheel brakes were used to decelerate the towing vehicle, and an emergency aircraft-type arresting gear and a blast mat were used for backup purposes.

The generating model was extensively instrumented to provide aerodynamic loads, and smoke-flow visualization and a laser velocimeter were used to provide details of the flow in the trailing wake of the model. The towing vehicle was modified with a trailer assembly for some testing which included a second model trailing behind the generator model. Aerodynamic forces and moments experienced by the trailing model were measured by instrumentation, and the effects of various modifications to the wing design of the generator aircraft were assessed.

Initial testing in the VRF focused on the dynamics of trailing vortex phenomena, during which significant advances were made in the understanding of the physics and decay of trailing vortices. Trailing models of small jet transports and general aviation aircraft were used to correlate the severity of loads experienced by trailing aircraft with predictions from theory and analytical studies. Extensive modifications to the wings of generator aircraft were evaluated including wing-tip devices such as winglets and splines; differential trailing-edge flap deflections; wing-tip mounted engines; and differential power settings for conventional pod-mounted jet engines. Results of the VRF tests were included in the larger NASA program on the wake vortex hazard, and were correlated with results from flight tests for specific aircraft. Following the termination of the wake vortex hazard program in the late 1980s, the VRF was used for studies to improve the dispersal patterns of particles released from agricultural aircraft. The objective of the research was to improve spreading efficiency and minimize undesirable features such as drift of chemicals. In these studies, scaled particles were released from a model and the dispersal results were measured on the ground plane in the facility. The last research activities in the VRF involved detailed studies of the aerodynamic lift experienced by short takeoff and landing (STOL) fighter aircraft during dynamic approaches to landing. Specifically, the aerodynamic lift measured on a model propelled over a simulated descent ground plane in the VRF was compared to results obtained over a moving belt in the Langley 14-by 22-foot tunnel.

The Vortex Research Facility was decommissioned and mothballed in March 1988 and was subsequently demolished.

Email from retired researcher Joe Chambers to Mary Gainer on 30 June 2015 regarding the car equipment:

I was head of the branch that did the Vortex Facility work. I spoke to my friend, LaRC retiree George Greene, who was the last project manager at the facility, this morning and he confirmed my remembrance that the car equipment used in the VRF was an Olds Toronado. The Pontiac convertible in question was never used at LaRC. We don't know what the Pontiac was used for at Wallops.

At the end of our program, the Olds engine was sent to a hop-up shop for mods to increase speed in the VRF for higher Reynold's numbers. We're fairly certain that the equipment was disposed of at the conclusion of tests. FYI, George is a consultant in Hampton specializing in wake vortex accidents, and the last technician to work on three Olds was Rusty Mchatton, who lives in York County.

[top] Photos

1941 Digging Foundation for Tank #21941 Digging Foundation for Tank #21941 Construction of Tank #21941 Construction of Tank #21942 Interior Construction1948 Floor Plan and Elevation1970 Exterior view1981-07-17 Wake Vortex Flow Visualization Tests of a Boeing 747 Model737 Model Approaches Wake of 747 ModelWing Model with Tip Engine Simulator747 Model747 Model on CarriageAgricultural Aircraft ResearchDC-4 Model with SplinesB747-400 Model on StrutSketch of Vortex FacilityTow CarriageVRF ModelWake of 747 ModelWake of Agricultural Aircraft ModelWing Model on Original Tow CarriageWing Model with Splines

[top] Film Clips

[top] Impacting Structures Facility

1959: Water Landing Characteristics of a 1/6-Scale Model Re-entry Capsule with an 80-Inch Heat Shield
1960: Landing Energy Dissipation for Manned Re-entry Vehicles
1961: Landing of Manned Re-entry Vehicles
1961: Effect of a Load-Alleviating Structure on the Landing Behavior of a Re-entry Capsule Model
1962: Preliminary Landing Tests of a 1/6 Scale Dynamic Model of a Lunar Excursion Vehicle
Investigation of the Landing Characteristics of a Re-entry Vehicle Having a Canted Multiple Airbag Load Alleviation System
1963: Characteristics of a Lunar Landing Configuration Having Various Multiple-Leg Landing Gear Arrangements
1963: Landing Characteristics of a Re-entry Vehicle with a Passive Landing System for Impact Alleviation
1964: Dynamic Model Investigation of the Landing Characteristics of a Manned Spacecraft
1965: Model Investigation of Techniques for Full Scale Landing Impact Tests at Simulated Lunar Gravity
1965: Landing Characteristics of the Apollo Spacecraft with Deployed Heat Shield Impact Attenuation Systems
1966: Dynamic Model Investigation of the Rough Water Landing Characteristics of a Spacecraft
1967: Dynamic Model Investigation of Water Pressures and Accelerations Encountered During Landing of the Apollo Spacecraft
1967: Flight Test of Ringsail Parachute Deployed at Mach 1.39

[top] Vortex Research Facility

View of Tow Carriage of Vortex Research Facility
NASA Wake Vortex Research Including Penetration of Wake by Probe Aircraft
Model Wake Studies in Smoke in Vortex Research Facility
Wake Vortex Studies of a Simple Model
NASA Wake Vortex Studies
Dispersal of a Cloud of Droplets

[top] Documents

1942 Floor Plan

1942 Real Property Record

1964 Description of Impacting Structures Facility

1966 Facility Resume

A Transonic Investigation of Base Pressures Associates with Shallow Three-Dimensional Rearward-Facing Steps

1975-01 Vortex Research Facility

1975-04 Floorplan

1978-07-12 Floorplan

Status of Aerial Applications Research in the Langley Vortex Research Facility and the Langley Full Scale Wind Tunnel. Frank L. Jordan, Jr., and H. Clyde McLemore. 1978. TM-78760.

1981-06-15 Floorplan

1984-10-15 Planneed Use of 720B

1985-03-18 Change in Building Designation

1988-03 Memo-Mothballing of Vortex Facility, and Transfer of Facility Coordinater Duties

Vortex Research Facility

1999-08-02 Floorplan

Investigate Current and Planned Uses for B720 Complex

Vortex Attenuation

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