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Massive Forces for Heavy Industry

Measuring large forces, such as the thrust of a rocket engine or the deflection of an aircraft wing, requires well-calibrated force sensors. NIST’s unique Million Pound Deadweight Machine provides these necessary calibrations for aerospace and other industries that need to measure huge forces.

A man in a hardhat standing on top of the million-pound weight stack with a person standing at the bottom.
Credit: J. Lee/NIST
Rigging crew reassembling the million-pound weight stack in March 2016.

NIST’s Million Pound Deadweight Machine is used to apply huge, but very precise forces to calibrate sensors. In the International System of Units (SI) the machine is known as the 4.45 meganewton deadweight machine, the newton being the internationally accepted unit of force. It is by far the largest machine of its kind in the world—using a series of weights, each as heavy as two school buses, it can apply a force as large as a fully loaded jumbo jet. Industries that rely on this unique calibration capability include the U.S. military, U.S. aerospace manufacturers such as Boeing, and several top-end commercial force calibration labs. Through the calibration labs, which have their own customer base, the NIST calibration service indirectly impacts many other important commercial sectors such as rail and public transportation and the oil and gas industries.

When designing new planes and rockets, engineers need to know whether their materials and designs will be able to withstand the massive forces that occur on takeoff and during flight. Similarly, oil drilling rigs, trains and technologies protecting warfighters have to be designed—and tested—at the forces experienced during operation.

NIST’s scientists use the Million Pound Deadweight Machine to calibrate customers’ sensors for use in research at their own facilities, or for commercial labs to calibrate other sensors for still more customers. For customers who need the highest precision large-force work, NIST must perform the calibration in-house. Commercial labs routinely use NIST’s calibrated sensors to make perhaps hundreds of subsequent calibrations for their own customers at several thousand dollars per calibration.