XV-15 litho - NASA's History Office

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Prior to the start of flight operations at Ames, the Government Project Office initiated
the development of the data acquisition system for the TRRA. The requirement
to monitor numerous structural load parameters in real-time at a ground
station dictated the need to improve the acquisition, processing, and display of
the digital data. This enhanced capability was developed, with the input of
TRRA project funding, by the Ames Avionics Systems Branch. Since some of
the test operations would be performed at the remote Crows Landing Naval
Landing Field, a duplicate data acquisition and processing capability was developed
at that site. To allow the ground safety monitoring crew to be located at
either location during testing, a telemetry data “repeater” was installed on 3900foot
Mount Diablo, one of the higher topographical features in the San Francisco
Bay area. For tests that called for the XV-15 to fly near Crows Landing or over
the adjacent San Joaquin Valley, while the monitoring crew remained at Ames,
the aircraft’s telemetered data would be initially received by the Crows Landing
data station. This signal was then sent to the repeater where it was transmitted to
the telemetry receiver at Ames. With the addition of video coverage, the remote
management of flight tests at Crows Landing became as routine and efficient as
if the aircraft was flying at Ames.
The NASA Ames ground data acquisition group developed and maintained the
control rooms at Moffett Field and at Crows Landing, from where the Test
Director communicated with the flight crew and the ground test-support personnel.
Each control room had a monitor that displayed aircraft status and critical
parameter values (such as loads or moments) and had four strip-chart recorders
that provided time histories of a total of thirty-two key items (selected for each
test) in engineering units in real time. These strip-chart recorders were monitored
by engineers or technicians familiar with the behavior of the items being monitored,
and who would alert the Test Director if allowable-limit values were
approached or exceeded. In addition, the ground data acquisition group would
process all data from the flight tapes for post-flight review, and would calculate
the accumulated “fatigue damage” to structural components due to oscillatory
loads in excess of the “infinite-life” limit.
In addition to working with the group developing the ground data acquisition
and processing capabilities, Mike Bondi of the TRRA Project Office was also
responsible for the development of an interactive database program which could
be used by engineers to analyze the flight test results. This program would be
capable of storing a large volume of data, retrieving data sets within constraints
defined by the engineer, providing a variety of data processing options, and generating
data tables or plots in a number of user-defined formats. This work was
contracted to Analytical Mechanics Associates of Sunnyvale California in 1980
and the resulting program was called the Tilt Rotor Engineering Database
System (TRENDS). In addition to the TRRA, TRENDS was also successfully
used for other Ames flight research activities such as the JUH-60A Black Hawk
Airloads project and the Quiet Short-Haul Research Aircraft (QSRA) Jump-
Strut project.