The Airspeed indicator on the Lockheed L-1011 was made by SPERRY RAND Flight Systems Divison. Sperry Rand, by the way no longer exists, they got soled off after the UNISYS takeover to Honeywell and parts of the gyroscope group got sold to Martin Marietta which is now part of the Lockheed Group.
See the next picture for interesting decal on the instrument describing airspeed indicator limitations.
The instrument case is held in place by two screws on the connector side of the instrument.
The airspeed/mach indicator is very neatly designed and organized. There are basically three sections to the instrument. The front section is dominated by a very complex gear mechanism for the airspeed indicator needle, the VMO needle and the Mach Speed digit drum. There are also 3 flags for each of the systems. Further, there is a mechanism for a speed bug that is purely mechanical.
TOP View
RIGHT HAND SIDE VIEW
Most Sperry instruments, you will see that later with the VSI, use DC motors in conjunction with differential resolvers. In the following picture you can see the DC motor for the Airspeed Indicator and one of the six Differential Resolvers in the instrument.
BOTTOM VIEW
LEFT HAND SIDE VIEW
The VMO needle is moved by a DC torque motor. The motor basically applies torque to the spring loaded VMO pointer. The only bad thing is that the torque motor requires up to 47.5V of power to be operated with ... a little more than I had hoped to use for this project piece.
The following picture is a closeup of one of the six differential resolvers in the instrument. All differential resolvers have the same characteristic:
- SYNCHRO - DIFFERENTIAL RESOLVER - 400Hz
- ROTOR - 3 PHASE 11.8 VOLTS
- STATOR - 2 PHASE 26 VOLTS
The image below shows one of the flags energized.
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