FGproperties/Systems/static

It has been suggested that this article or section be merged into FGproperties/Systems/Pitot. Discuss this merge. This has been proposed since April 2019.

The static system measures the static pressure. So all influences of airspeed are eliminated. In real life this is however not always easy. Effects from angle of attack, side-slip, flap defection, gear extension, engine power setting and airspeed are present and for the aircraft designer it is not always easy to find a good position for the static port.

Usually the number of static systems are equal to the number of pitot systems.

In Flightgear there are 3 types of static systems modeled.

• Type 0 (default): the perfect sensor. No measurement failures.
• Type 1: Dual static ports on the fuselage sides. Side-slip angle influence only.
• Type 2: Static port on the pitot tube. Both angle of attack and side-slip influence.

If you want to use type 1 or 2:

  <static>
    <name>static</name>
    <number>0</number>
    <tau>0.1</tau>
    <type>1</type>
    <error-factor>0.5</error-factor>
  </static>

The output property /systems/static[n]/pressure-inhg is filtered. Therefore, if you want to see the effect of the measurement failure, "tau" should be 0.1 or smaller. The "error-factor" should be between 0.2 and 0.7. Setting it to 0 equals a "perfect sensor". A setting of 1 means the whole (projected on static port face) impact pressure is applied. This is not realistic as usually there are more than one static pick-up points and so the pressure increase gets "flattened".

The "tau" parameter controls the responsiveness of the filter that is applied after the calculation of the new values (responsiveness = dt/tau).