New Agency Standard for Wind Tunnel Model Systems Criteria
NASA released NASA-STD-8719.28, Wind Tunnel Model Systems Criteria, effective Oct. 10, 2022. The new agency standard — which replaces local center standards at Ames Research Center, Glenn Research Center and Langley Research Center — ensures models can move seamlessly between the centers for testing in various wind tunnels.
Over a number of years, NASA worked to reduce redundancies of facilities at various NASA centers, including wind tunnels. As a result, it is now more common for a model to have to be tested at more than one of these centers that conduct aero-research to fully test models under various conditions.
“The desire was to make it easier to move a model from Langley to Ames or Ames to Glenn or whichever order,” said Douglas Weber, model safety engineer at Langley. “We wanted to standardize requirements so we could simplify the other facility’s safety review.”
The Aerosciences Evaluation and Test Capabilities group drove the demand for this change, as it has primary responsibility for the management of the major facilities. The uniform requirements, regardless of center location, simplify the use of these facilities.
“While it is one of many requirements for testing in a facility, it is one that we can streamline,” said Weber. “The main benefit of this change is that if we have a model that is designed for Ames, and they [the researcher] want to test it at Langley under the same conditions and loads, they shouldn’t have to do any redesign or new analyses, so it’ll save time, money and resources.”
While the agency-level policy simplifies the processes, for the most part it is consistent with what centers already had.
“We did some adjustment for factors of safety,” explained Weber. “For example, Glenn had to drop its safety factors from five to four on ultimate material strength, that is from being five times as strong as needed to four, which is what the other two [centers] already required. Overall, the centers had very similar requirements.”
One of the biggest differences among the previous center standards was lessons learned.
“One benefit we got from this new standard is that Glenn has a lot more rotating machinery experience, so we incorporated that into the new standard, where Ames and Langley didn’t have as much in their documents,” said Weber. “So, in combining them, we actually expanded the material covered in the document. It’s makes use of lessons learned at different centers and gives us a more precise, better interpreted document.”
The new standard is called out in the Statements of Work for model suppliers and it takes precedent over any center standards that are still in place as the centers work to remove local references from their other documentation.
Questions about NASA-STD-8719.28 should be sent to the applicable center’s model safety engineer; those unsure who that is can contact Weber.