RE: What is compass dampening fluid?
Most companies use alcohol. The fluid can vary according to each company's design and goals. Here's what SIRS' Compass says about their fluid. [*]What is the Silicone damping for ?
The compass card needs to be damped to prevent it from over-swinging and becoming too sensitive to aircraft movements. . We use the silicone fluid to control card movement as this has a much better damping property than the normal Kerosene or alcohol alternatives. Additionally, silicone fluid has a viscosity value that remains virtually constant throughout the operating temperature range of the compass.
By using a smaller card inside the compass, than used in other compass units, we are able to reduce the forces subjected on the body of the card. The apparent compass card size, that is an industry standard, is actually magnified by the spherical front face of the compass bowl.[/list]