The INSCO 6505A triple tachometer is a three channel servoed
tachometer designed primarily for use on dual engine helicopters.
The speed of both engines and the rotor are displayed by three
concentric pointers. All channels are independent of one another, so
that a failure in one channel will not affect the others. The engine
channels are normally calibrated in percent rpm and rotor channel
reads direct rpm, however, any arrangement is possible.
6505A, all channels will operate from either a two or four pole
tachometer generator, or a monopole transmitter. Overall accuracy is
+ / - 0.5%. Only 28 volt external power and the tach generator
signal is required for operation.
The indicator is qualified to TSO-C49A, and meets the FRI
requirements of MIL-l-6181.
The INSCO™ 6505A Tachometer 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 steel 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.
The 6505A indicator is available with overspeed or underspeed
warning circuitry, and with key-operated reset, if required.
All pointers will return to zero in the event of power failure, so
that incorrect information is not displayed to the pilot.
The tachometer is available in either a standard round case,
'O'-ring or hermetic sealed, or an environmentally sealed ARINC ATI