By Julie Cooper

Each month in “Slice of History” we feature a historical photo from the JPL Archives. See more historical photos and explore the JPL Archives at https://beacon.jpl.nasa.gov/.

Low Speed Wind Tunnel — Photograph Number 383-6109Bc

In December 1974, this photo was taken of the Low Speed Wind Tunnel. NASA’s Jet Propulsion Laboratory had 21-, 20-, and 12-inch wind tunnels that were very well documented, but an April 1967 report about JPL wind tunnels does not mention this facility and very little is known about it. It appears in 1961 drawings of building 80, which was next door to the main wind tunnel building but it may have been relocated years later. The March 1968 JPL telephone book indicates that there was a Low Density Wind Tunnel in building 183, room 601, belonging to the Fluid Physics Section. The section number prefix for this image indicates that it was photographed for the Research and Advanced Concepts Section, but the photo was taken at the request of Paul Massier of the Structures and Dynamics Section. Massier was seen in the June “Slice of History” blog taken in the anechoic chamber.

This post was written for “Historical Photo of the Month,” a blog by Julie Cooper of JPL’s Library and Archives Group.

By Julie Cooper

Each month in “Slice of History” we’ll be featuring a historical photo from the JPL Archives. See more historical photos and explore the JPL Archives at https://beacon.jpl.nasa.gov/.

Anechoic Chamber — Photograph Number 383-5765Ac

This aerodynamic noise facility, also called an anechoic chamber, was used to study the noise generating mechanisms in supersonic and subsonic jets in the early 1970s. It was housed at NASA’s Jet Propulsion Laboratory in building 57 (which no longer exists) located next door to the wind tunnel that was in building 79 at the time. The large round opening in the wall is an exhaust silencer inlet. Standing next to it is Paul Massier, co-author of a technical report about this chamber. On the right is a support structure for microphones. Fiberglass wedge blocks cover the ceiling and walls, which were mostly reinforced concrete. Spaces were left open to allow for observation windows and instruments to record test data. There were also openings in the walls that allowed air to flow into the chamber to replace the air forced out during tests.

This post was written for “Historical Photo of the Month,” a blog by Julie Cooper of JPL’s Library and Archives Group.