The INSCO 4328 series servoed torquemeter represents
state-of-the-art accuracy combined with dependable performance. The
4328 series most commonly provides critical engine or transmission
torque information to the pilot but the 4328 also offers the
versatility to monitor any aircraft pressure where accuracy is
INSCO 4328 indicator operates from a high-impedance strain-gauge
transducer. In most torque applications, the transducer used is
AeroPanel-INSCO part number 1007-1023, a 70 psi differential unit.
When used to measure direct pressures, a 1007 series gauge pressure
transducer should be used. The indicator develops a closely
regulated 10 volt output for transducer excitation. The only
external requirements are 28 volt DC power, and the transducer
The 4328 torquemeter has been designed with maximum reliability in
mind. There are no punched gears or bushings in an INSCO gearhead.
We use precision machined close-tolerance aluminum and stainless
gearing and every gear shaft runs in ABEC7P miniature bearings. All
electronic components are selected with a wide 'cushion' to prevent
premature failure, and much of the circuitry is hybridized into a
custom thick-film circuit.
This indicator is available with an optional overtorque warning lamp
to indicate when a preset value of torque has been exceeded. Once
on, the lamp can only be turned off by a key operated switch. This
option also includes a self-test function.
The indicator is fully qualified to TSO-C47, type II, for pressure
application. All inputs and outputs are FRI filtered to conform to
MIL-I-6181. As with all INSCO servoed indicators, the pointer
returns to zero in the event of a power failure, so that incorrect
information is not displayed to the pilot.