Photo By Ana Henderson | The Metrology and Simulation Division at U.S. Army Yuma Test Center, which performs...... read more read more
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Rain in Arizona is not something that comes often.
So, when a test plan calls for rain, U.S. Army Yuma Test Center (YTC) needs to be able to make it happen artificially. The addition of two new rain machines makes this capability as easy as turning on a faucet.
The Metrology and Simulation Division at YTC which performs environmental simulation testing recently built two rain units. One is a stationary indoor system, the Enclosed Rain Array System (ERAS). The other is a mobile outdoor system, the Modular Rain Array System (MRAS).
Instead of clouds, Dillon Mann and Zachary Alvarez used hoses, sprinklers and aluminum to make it rain.
YTC secured a grant from the Capability Program Executive Simulation,TrainingandInstrumentation office to modernize the ERAS indoor system. That’s where Mann, an engineer who performs design and analysis work for small to large components, and Alvarez, a climatic engineer, both with the Metrology and Simulation Division, got involved.
From PowerPoint concept to acquisition the process took roughly a year and a half. Then the building phase began.
Mann and Alvarez used the water testing requirements outlined in military standards to guide their design process.
“Generally, it requires that you be able to output a consistent pressure of 40psi and depending on the test, sustained rainfall rate at different levels. Aside from that the main concern is adequate coverage of the item, because at least for one of the tests you are trying to test the water tightness of the item,” explained Alvarez, adding, “Fun fact, both procedure one and two have a limitation on the droplet size for the ideal rain.”
That meant they had to first find the nozzles to meet the droplet size in the military standard and then design around it.
“Nozzles were the main requirement of how we designed whole system” explained Mann. “It was really the starting point because we were designing the systems to a certain nozzle, because that would provide us with a certain spray pattern in order to meet the requirement.”
Once they found the correct nozzle the next challenge was finding a product that could hold the immense number of nozzles and hoses to meet the specified spray patterns.
Michael Schwitzing and Alvarez provided Mann with a layout of the space, requirements and a two-dimensional sketch. Mann used SolidWorks, a computer aided design software, to create a three-dimensional model.
“I mapped out everything on the software for both the ERAS and MRAS going from the connection from the pumps all the way to the nozzles.”
From there they needed to consider the weight of the apparatus.
“We are supporting so much weight overhead that we needed to have a structure to support the system without attaching to the existing building,” said Mann.
They found aluminum trusses seen at concerts to hold lights and speakers. Once the simulations verified the design was safe, the assembly began.
Mann’s skills as an engineer and designer plus Alvarez’s knowledge and attention to detail all played a role in the success of the ERAS and MRAS rain systems.
YTC can now accurately test items for the Warfighter for water resistance and tightness, either indoors or on location.
From blowing rain, overhead, or torrential rain, “if you want to determine if your test item is waterproof, this test will definitely tell you,” remarked Alvarez.
| Date Taken: | 03.23.2026 |
| Date Posted: | 03.23.2026 10:48 |
| Story ID: | 560721 |
| Location: | YUMA PROVING GROUND, ARIZONA, US |
| Web Views: | 162 |
| Downloads: | 0 |
This work, Making it rain: New artificial rain units at U.S. Army Yuma Proving Ground, by Ana Henderson, identified by DVIDS, must comply with the restrictions shown on https://www.dvidshub.net/about/copyright.
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