NASA Langley Research Center

Earlier this year, I had the privilege of working on a research project at NASA’s Langley Research Centre. Apart from interacting with world-renowned scientists and engineers, what impressed me most was the mind-blowing heritage of the site.

NASA Langley is the birthplace of large-scale, government-funded aeronautical research in the US. It was home to research on WWII planes, supersonic aircraft, the lunar landers and the Space Shuttle. Who knows how the Space Race would have panned out without the engineers at NASA Langley?

Today, Langley is at the helm of leading aeronautical engineering into the 21st century with technologies such as advanced composites, alternative jet fuels and the journey to Mars.

NASA Langley was established in 1917 as NACA’s (short for National Advisory Committee for Aeronautics and renamed to NASA in 1958) first field centre and is named after the Wright brothers rival Samuel Pierpont Langley, who’s Aerodrome flyer twice failed to cross the Potomac river in 1903.

Amid the new composites facilities I was working on  are strewn old gems such as NACA wind-tunnels from the 1920s and 1930s, and the massive “Lunar Landing Research Facility”, or simply “The Gantry”, used to test the Apollo lunar landings in the 1960’s. During Project Mercury NASA Langley was the home of the Space Task Group, a team of engineers spearheading NASA’s first human spaceflight between 1958 and 1963. The gantry has since been re-purposed for land-based crash landings, such as on the Orion spacecraft.

Another historic site is the Aircraft Landing Dynamics Facility (ALDF), a train carriage that could be accelerated by 20Gs up to 230 mph by a water-jet spewing out the rear, and used to test impact on landing gears and airfield surfaces.  The facility has provided NASA and its partners and invaluable capability to test tires, landing gear and understand the mechanism of runway friction. Prior to WWII many engineers were convinced that the abundance of rivers and sea water would mean that the aircraft would land primarily on water. As a result research on the mechanics of landing on terra firma was lagging behind and post WWII almost a third of all aircraft accidents could be attributed to landing issues [2]. Throughout its 52 years of operation the ALDF has saved thousands of lives by making aircraft safer.

As the centre’s original aim was to explore the field of aeronautics, specifically aerodynamics and propulsion, the world’s largest wind tunnel was constructed at Langley in 1934. At the time the Full-Scale Wind Tunnel was one of the first to fit an entire full-scale aircraft with a whopping 30 by 60 foot cross-section. The tunnel’s 4000 bhp electric motors (4000 bhp !!) accelerated the airflow to 118 mph (181 km/hr) and was used to test basically every WWII aircraft prototype. After the war, both the F-16 and the Space Shuttle were tested in the Full-Scale Wind Tunnel. Even though it was declared a National Historic Landmark in 1985 it was demolished in 2010.

As rocket research gained importance in the 1940’s the capabilities were extended from subsonic to supersonic and even hypersonic research. Even today the importance of aerodynamics research is obvious as one drives past the 14×22 foot subsonic wind tunnel on the way to the main gate.

The 1930s in the USA were a golden age for aeronautics. Before World War I, the US government and military did not place high priority on aeronautics research. In fact the total research spending between 1908 and 1913 totalled a measly $435,000 compared to a whopping $28 million spent by Germany. Thus put the US behind countries like Brazil, Chile, Bulgaria, Spain and Greece [4].

All of this changed when aeronautical research started to kick-off at NACA, specifically at Langley Research Center. In the 1930’s aerodynamicist Eastman Jacobs developed a systematic way of designing airfoil shapes, and to this day standard wing shapes are designated with a NACA identification number.

During the 1930s various airshows and flying competitions in Europe sparked competition to design the fastest aircraft. For example, the Schneider Trophy was an annual competition for seaplanes and was won on three occasions by Supermarine aircraft designed by Reginald J. Mitchell, who later used the insights gained from these competitions to design the iconic WWII fighter Supermarine Spitfire. However, at some point the speed records hit a wall just shy of the speed of sound and it was unclear if it was possible to break the “Sound Barrier” at all.

Researchers were having a tough time figuring out why drag increased and lift decreased as an aircraft approached the speed of sound. It was not until 1934 that a young Langley researcher John Stack captured the culprit on a photograph of a high-speed wind tunnel test of an airfoil.

As the aircraft airspeed approaches the speed of sound, small pockets of supersonic flow develop on the suction surface of the airfoil as the airflow accelerates over the curved profile. For thermodynamic reasons these pockets of supersonic flow terminate in normal shock waves and the ensuing increase in pressure exacerbates the adverse pressure gradient on the suction surface. Ultimately, this leads to premature boundary layer separation and thereby decreases lift and increases drag (see figure below). John Stack was the first person to capture this phenomenon on film and paved the way for supersonic flight in the years to come.

Other major accomplishments of NASA Langley Research Center include:

• The idea of designing specific research aircraft dedicated to supersonic flight, which led to the world’s first transonic wind tunnel
• Simulation and testing of landing in lunar gravity using the Lunar Landing Facility
• The Viking program for Mars exploration
• 5 Collier trophies, the U.S. aviation’s more prestigious award, including the 1946 trophy to Lewis A. Rodert, Lawrence D. Bell and a certain Chuck Yeager for the development of a wing deicing system. Fred Welck won the trophy in 1929 for the NACA cowling, an engine cover for drag reduction and improved engine cooling
• The grooving of aircraft runways to improve the grip of aircraft tires by reducing aquaplaning, now an international standard for all runways around the world.

On March 3rd the NASA reached a major milestone by celebrating its centennial. Since 1917 Langley Research Center has played an important role in the successes of American and international air and space travel. In recent years the media has focused mostly on new commercial space companies such as Orbital Sciences and Space-X.

But as Elon Musk rightly points out, Space X’s exploits would not be possible without NASA’s achievements throughout the last 100 years and its continuing support of the private sector. In fact, NASA made one of it’s first steps into public-private partnerships as early as the 1940’s with the development of the Bell X-1, the first manned aircraft to break the sound barrier.

In that respect join me in congratulating NASA to its centennial and to more exciting aerospace developments for the next 100 years!

 

References

[1] “Nasa langley test gantry” by Unknown – NASA. Licensed under Public Domain via Wikimedia Commons – https://commons.wikimedia.org/wiki/File:Nasa_langley_test_gantry.jpg#/media/File:Nasa_langley_test_gantry.jpg

[2] “Shooting for a better understanding of aircraft targets, ALDF hit its target” by Sam MacDonald (2015). http://www.nasa.gov/langley/shooting-for-a-better-understanding-of-aircraft-landings-aldf-hit-its-target . Published 8 May 2015. Accessed 22 May 2015.

[3] “Full Scale Wind Tunnel (NASA Langley)” by Photocopy of photograph (original in the Langley Research Center Archives, Hampton, VA [LaRC]) (L73-5028). Licensed under Public Domain via Wikimedia Commons – https://commons.wikimedia.org/wiki/File:Full_Scale_Wind_Tunnel_(NASA_Langley).jpg#/media/File:Full_Scale_Wind_Tunnel_(NASA_Langley).jpg

[4] “Nine notable facts about NACA” by Joe Atkinson (2015) http://www.nasa.gov/larc/nine-notable-facts-about-the-naca. Published 30 March 2015. Accessed 22 May 2015.

[5] “14×22 Subsonic Tunnel NASA Langley” by Erik Axdahl Axda0002. Licensed under CC BY-SA 2.5 via Wikimedia Commons – https://commons.wikimedia.org/wiki/File:14x22_Subsonic_Tunnel_NASA_Langley.jpg#/media/File:14x22_Subsonic_Tunnel_NASA_Langley.jpg

[6] “Transonic flow patterns” by U.S. Federal Aviation Administration – Airplane Flying Handbook. U.S. Government Printing Office, Washington D.C.: U.S. Federal Aviation Administration, p. 15-7. FAA-8083-3A.. Licensed under Public Domain via Wikimedia Commons – https://commons.wikimedia.org/wiki/File:Transonic_flow_patterns.svg#/media/File:Transonic_flow_patterns.svg

[7] “Pista Congonhas03” by Valter Campanato/ABr – Agência Brasil. Licensed under CC BY 3.0 br via Wikimedia Commons – https://commons.wikimedia.org/wiki/File:Pista_Congonhas03.jpg#/media/File:Pista_Congonhas03.jpg