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Air Data Static Transducer Unit

Technical Information

Catalogue No: C0117
Category: Air Data
Object Type: Sensor/Transducer
Object Name: Air Data Static Transducer Unit
Part No: 3D 763
Serial No: None
Manufacturer: Elliott Bros
Division: Unknown
Year of Manufacture: 1960
Width (mm):
Height (mm):
Depth (mm):
Weight (g):
Location: Main Object Store

Type No. 3D 763


Marconi Collection Ref: 2033

The Differential Pressure Transducer contains an aneroid capsule, or diaphragms, which expands and contracts with the pressure input from the pitot tube. The case around the diaphragm is airtight and is vented to the static port. Some units will have multiple aneroid capsules to multiply the movement. The difference between the pitot pressure and the static pressure is called dynamic pressure. The greater the dynamic pressure, the higher the airspeed. The movement of the diaphragm is mechanically coupled to a non-linear cam assembly with a large number of adjustable grub screws to set the desired profile. The cam output couples to a large spiral wound resistor which translates the movement into an electrical output of indicated airspeed. The gear train is too much for the capsule transducer to drive so it is coupled to a Synchro motor which reinforces the drive to the non-linear cam and resistor.

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