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Height Lock Transducer

Technical Information

Catalogue No: C0107
Category: Air Data
Object Type: Sensor/Transducer
Object Name: Height Lock Transducer
Part No: HL/10A/270/31
Serial No: 53174
Manufacturer: RW Munro
Division: Unknown
Year of Manufacture: Unknown
Width (mm):
Height (mm):
Depth (mm):
Weight (g):
Location: Main Object Store

Height Lock
R.W.Munro Ltd London.
[internal marks]
Inst. 53174
[other marks]
Inwards Goods number: IG733479


The object is an aircraft-type panel instrument in black Bakelite with a transparent front. Inside the aneroid capsule, potentiometer and linkage are visible. There are three electrical connections at the side (marked A,B,C) and three barometric connections at rear (marked P, S and blank). These inputs are from the Pitot Tube and the Static Port and they drive an aneroid capsule. The difference between these two pressure inputs gives the dynamic pressure which is a measure of Indicated Airspeed (IAS). The capsule drives a mechanical system that moves a wiper along a wire wound resistor such that an electrical output is given via the three external tags marked ‘A’, ‘B’ and ‘C’. The electrical output may have been used to drive an Altimeter or Airspeed indicator but its title (Height Lock Transducer) would suggest that it was part of the Autopilot system that can be used to maintain a preset altitude.
The instrument was made by R.W.Munro but formed part of a system marketed by Elliott Bros and was in the original Marconi collection: Marconi Collection Ref: 2023.

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