|Object Name:||Air Data System, Pitot-Static Capsule Sensor Mechanism|
|Year of Manufacture:||1960|
|Location:||Main Object Store|
Marconi Collection Ref: 2037
The Differential Pressure Transducer contains two aneroid capsules, 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 two rows of fifteen adjustable grub screws to set the desired profile. Within the casing is a wire wound resistor which is driven by the cam mechanism such that an electrical output of indicated airspeed is provided corrected by the cam profile for the non-linearity of the diaphragm movement.
This is an item from the original Marconi Collection and is without the sealed cover over the diaphragm assembly and also lacks the non-linear cam.