ARMY AL&T
HOT ANDCOLD
For years, the Army has used ambient temperature extrapolation as a shortcut in test and evaluation, but electronically controlled powertrains have changed things and the Army test community is identifying new risks from an old Army practice— and potential cost savings.
by Steven Zielinski and Paul Maguire M
ilitary vehicles have some of the most demanding automotive specifications, requiring operation in extreme environments ranging from arctic (50 below) to desert (120) condi- tions. (All temperatures are Fahrenheit.) During development, U.S. military vehicles must be tested successfully in those conditions. Tat’s problematic because no test center in the
U.S. gets that hot long enough to test accurately at 120. Te Cold Regions Test Center in Alaska meets Army regulation for ambient temperature (Army Regulation 70-38, “Research, Development, Test and Evaluation of Materiel for Worldwide Use”). However, testing for desert conditions often occurs below the 120-degree threshold.
As a result of test program schedule constraints, test vehicle availability, proving ground selection and other factors, military vehicle mobility performance is often tested in the window of only 90 to 110 degrees. Is this good enough when the requirement is 120 degrees? What are the risks to our Soldiers operating these vehicles in desert warfare? By not testing at this upper extreme, vehicles may not be able to reach top speed, climb steep hills or tow disabled vehicles without overheating or suffering catastrophic damage.
THE REALITY OF T&E In the development cycle of a tactical or combat vehicle, the cost of test and evaluation can represent a significant portion of the program’s research, development, test and evaluation (RDT&E) budget. Indeed, vehicle test costs can run into the hundreds of millions of dollars. In a Spring 2018 article in Army AL&T, Robert Mortlock, Ph.D., of the Naval Postgraduate School wrote that the cost of test and evaluation in the Ground Combat Vehicle was a whopping $417 million.
Where are legitimate places to reduce testing cost? Te matter of temperature extrapolation might provide a clue.
To address the extreme temperature issue, the Army has been using a linear extrapolation of powertrain test data based on the ambient temperature.
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