National Aeronautics and Space Administration

Glenn Research Center

Test Equipment
PSL test chamber with hatch open
Test Chamber

The PSL No. 1 and 2 Shop and Access Building contained two test chambers, a control room, and balance chamber. The engine being tested was installed inside the test section of one of the chambers. Extensive instrumentation was fitted on the engine prior to the test. Once the chamber was sealed, the altitude conditions were introduced, and the engine was ignited. Operators in the control room could run the engine at the various speeds and adjust the altitude conditions to the desired levels. Obtaining the desired test conditions could be a difficult process; once they were reached the operators would continue running as long as possible.

     Access Building Floor Plans (PDF, 416KB)

Altitude Chambers
Lengthwise View Through Test Section
Chamber No. 2

The two 100-foot-long altitude chambers ran parallel to one another inside the Access Building with a control room in between. The chambers were pressurized and water-cooled with a number of access points. Each chamber was comprised of three sections: the test section, inlet section, and exhaust section. The conical inlet section contained a set of vanes that stretched across the chamber to straighten the airflow. The test section was separated from the rest of the chamber by a front and rear bulkhead. An engine platform inside the test section was used to both hold the engine and measure its thrust loads and drag. An overhead crane was used to lower the engine onto the stand. A large clamshell hatch sealed the test section after the engine had been installed. The engine’s exhaust was ejected into exhaust section. This tubular section expanded as it connected to the primary cooler.

PSL could be configured in either a direct-connect or free-jet mode. The direct-connect was the simplest way of studying the internal performance of the engine. The engine was mounted on the thrust stand inside a test chamber with the air flow connected directly to the engine inlet. To test the air inlet system though, a free-jet method was required. A nozzle was used to create a supersonic jet of air that enveloped the engine inlet in supersonic altitude air. The stream was powerful but narrow so it did not permit the study of air flow over the complete engine. The free-jet setup was more beneficial than the direct-connect since the entire engine system, including the inlet duct, could be studied.

Chamber No. 2
Chamber No. 2
Chamber Diagram
Chamber Diagram
Chamber Interior
Chamber Interior
Control Room
Operators in PSL control room
Control Room

The control room for PSL No. 1 and 2 was located between the two chambers on the second floor of the Shop and Access Building. The control room had separate stations for each chamber. Inside the control room operators ran the engine and worked with other technicians in the Equipment Building to create the proper altitude conditions inside the test chamber. During the 1950s, large manometer boards were set up in the rear of the room. Cameras on fixed stands recorded these pressure measurements. A console was set up in the center of the room to monitor the manometer readings.

The control room was frequently updated and modified. The manometers were replaced with electronic equipment by the early 1960s. A number of television consoles were installed so that the test engineers could view the engine in the chamber during the test. Temporary data recording equipment could be installed for certain tests and later removed, and the control panels were rearranged periodically.

Test engineers in PSL control room
Test Engineers
PSL control room in the 1960s
1960s Controls
PSL control room in 1970
Updated Control Room
PSL technician instruments test
Technician in PSL

To obtain useful data from the tests, instrumentation had to be installed in both the engine and the test chamber. The setup varied depending on the requirements for the specific test. It could take weeks or even months for technicians and electricians to install the multitude of thermocouples, rakes, and other required instruments. Sometimes each compressor stage had to have its own readings. This could often be begun in the shop area before the engine was installed in the chamber. Once the test article was in the chamber, the staff could access it through the main hatch, which was a large clamshell mechanically operated lid, or a smaller access door in the inlet section. The engine itself was atop a thrust stand that measured the thrust and drag. A periscope camera was set up inside one of the chambers in the 1950s. In the 1960s additional cameras were set up so that researchers could view the tests from the control room.

Rakes on display
Technician instruments rocket engine
Instrumenting Engine
instrumentation on J71 compressor
J71 Compressor