Dual P-S Air Pressure Transducer Module

Technical Information

Catalogue No: C1048
Category: Air Data
Object Type: Sensor/Transducer
Object Name: Dual P-S Air Pressure Transducer Module
Part No: 81-40-11
Serial No: 036/69
Manufacturer: Elliott Bros
Division: Unknown
Year of Manufacture: 1969
Width (mm):
Height (mm):
Depth (mm):
Weight (g):
Location: Archive Object Store

Type 81-40-11
P-S Transducer
Ref. STP1991654
Ser. 035/69


This Pitot-Static Transducer was used in the Jaguar Air Data system. An aircraft airspeed unit measures the difference of pressure between the Pitot (or total pressure) and the Static pressure.
The Pitot pressure is obtained from the Pitot Tube and is a measure of ram air pressure (the air pressure created by vehicle motion or the air ramming into the tube). The Pitot tube is most often located on the wing or front section of an aircraft, facing forward, where its opening is exposed to the relative wind. When airspeed increases, the ram air pressure is increased, which can be translated by the airspeed indicator.
The static pressure is obtained through a static port which most often is a flush-mounted hole on the fuselage of an aircraft located where it can access the air flow in a relatively undisturbed area. Some aircraft may have a single static port, while others may have more than one. A Pitot-static tube effectively integrates the static ports into the Pitot probe. It incorporates a second coaxial tube (or tubes) with pressure sampling holes on the sides of the probe, outside the direct airflow, to measure the static pressure. When the aircraft climbs, static pressure will decrease.
This unit contains two independent P-S Capsule Units 81-04-05 with Ser. Nos: 065/69 and 066/69. Each aneroid capsule (or usually two capsules to magnify the movement) which is coupled to an arm sliding along a wire wound resistor. A small servo motor was used to further amplify the movement of the capsules to operate the internal gear train This simple arrangement transmits the difference signal between the Pitot and Static pressure to a remote indicator for Indicated Air Speed. The signal is also fed to a locking solenoid used in Height Lock mode to maintain barometric height.
The nameplate is also marked "Ref STP1991654" with "EBLR Apr 90" alongside the nameplate.

Click to enlarge Click to enlarge
Related Items: