Arrighi - Pursuit of power : NASAs Propulsion Systems Laboratory no. 1 and 2

NASA History Program Office

Public Outreach Division

National Aeronautics and Space Administration

There were several ways to test engines, but test stands provided the most efficient and useful method. A single stand could be used to study many types of engines in an environment that was safer and more efficient than that on research aircraft. Efficiency improved because installing instrumentation and measuring thrust is more difficult in flight research.3

Pilots found early on that engines behave differently in altitude conditions than at sea level, and engineers quickly determined that the test stands needed to simulate altitude conditions in order to properly test engines. In general, this meant reducing the temperature and pressure of the air and creating velocity. Removing moisture from the air and expelling the engines exhaust were also important.

Unlike wind tunnels, these altitude chambers were generally used to study only the engines, not the engine cowlings or mounts. Another difference was that the amount of power and air required was far less than for tunnels because the air was ducted only through the enginenot through the surrounding test section.

PSLs two chambers, referred to as PSL No. 1 and 2, could simulate the internal airflow conditions experienced by the nations most powerful engines over a full range of power and altitude levels. This allowed researchers to analyze the engines thrust, fuel consumption, airflow limits, combustion blowout levels, acceleration, starting characteristics, and an array of other parameters. The range of PSLs studies was later expanded to include noise reduction, flutter, inlet distortions, and engine controls.

There were three distinct eras during PSL No. 1 and 2s operating years, each with its own group of researchers: NACA Lewiss Engine Research Division managed the ramjet and turbojet period of the 1950s, the Chemical Rocket Division conducted most of PSLs research in the 1960s, and the Airbreathing Engines Division assumed control for the turbofan and supersonic inlet studies of the late 1960s and 1970s. The researchers and test engineers in these divisions developed and ran the tests. The mechanics and technicians in the Test Installations Division maintained the PSL and integrated the test equipment into the facility throughout the years.

Image credit: NASA C195950861

Image 2: The PSL No. 1 and 2 facility viewed from the west on 9 June 1959. The Shop and Access Building containing the two test chambers is to the left, and the larger Equipment Building containing the exhausters and compressors is behind and to the right.

NACA management initiated its plans for the PSL in November 1947, and construction started two years later. When the facility began operating in October 1952, PSL No. 1 was used for turbojet studies while PSL No. 2 concentrated on ramjets.

By the late 1950s, Pratt & Whitney, Wright Aeronautical, and the U.S. Air Force began building their own propulsion labs and altitude facilities. The PSL remained a vital resource by continually upgrading its two chambers, control room, and air-handling system. The installation of a pebble bed heater in the late 1950s permitted hypersonic studies, and the installation of a flamespreader in the mid-1960s allowed more powerful engines to be tested without damaging the cooling equipment.

By the 1960s rocket systems of increasing complexity were being studied in both chambers, including an extensive investigation of the Pratt & Whitney RL-10 in PSL No. 1. In the late 1960s, the PSL again turned to airbreathing engines for aircraft. Unlike the studies in the 1950s, this new effort included propulsion systems for civilian aircraft.

In 1967, construction was undertaken on a new PSL building with two additional, more powerful altitude chambers, referred to as PSL No. 3 and 4. All four PSL chambers were used for turbojet and turbofan studies from 1972 to 1979. Budget concerns led to the ultimate shuttering of PSL No. 1 and 2 in 1979.

After years of idleness that included the installation of temporary office space around the test chambers, the NASA Glenn Research Center decided to remove the original facility in 2004. Five years later, the PSL No. 1 and 2 facility was demolished. The PSL No. 3 and 4 facility and the Equipment Building, since renamed the Central Air and Equipment Building, continue to operate today. The PSL remains the National Aeronautics and Space Administrations (NASAs) sole facility for testing full-scale aircraft engines in simulated flight conditions.

The Cleveland laboratory began operation in 1942 as the NACA Aircraft Engine Research Laboratory (AERL). In 1947 it was renamed the NACA Flight Propulsion Laboratory to reflect the expansion of the research. In September 1948, following the death of the NACAs Director of Aeronautics, George Lewis, the name was changed to the NACA Lewis Flight Propulsion Laboratory. On 1 October 1958, the lab was incorporated into the new NASA space agency, and it was renamed the NASA Lewis Research Center. Following John Glenns flight on the space shuttle, the center name was changed again on 1 March 1999 to the NASA Glenn Research Center.