Measurement Mystery #12

A TRUE STORY of a test jet engine---the first 25,000-pound dry-thrust gas turbine in the United States: The second time it was started up, its first-stage turbine blades burned up.

The measurement system said that everything had been fine! According to the turbine inlet gas temperature recordings from the engine's first start, the transient temperature had reached no more than 1600 F. This was well below the maximum permitted temperature of 2500 F. (And the thermocouple measurement system was easily within its calibration limits.)

Yet after the metallurgists conducted their examination, they stated that the blades had been exposed to temperatures far above the permitted limit.

What went wrong?

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To learn what happened to those gas-turbine blades, simply send a blank e-mail message to meas-sys@mailback.com for a prompt e-mail reply.

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