Howto:Get the standard atmosphere

Sometimes you want to get the standard atmosphere for example when testing a flight dynamics model (FDM).

Why using the standard atmosphere?

Usually aircraft performance is given for the International Standard Atmosphere (ISA). Often these numbers or graphs are complemented with additional ones for a colder or warmer atmosphere (for example ISA+20°C).

When comparing performance of FlightGear aircraft against published performance of real world counterparts it is of course helpful to do that against the same conditions (real world performance numbers are reduced, mathematically corrected, to the performance in a standard atmosphere).

How to get it

1. Start up FlightGear
2. Open up the property browser (e.g. via --prop:browser=environment)
3. Set /environment/config/enabled to false
4. Set /environment/atmosphere/temperature-deg-sea-level to 15
5. Set /environment/atmosphere/pressure-inhg-sea-level to 29.92126
6. Set /environment/atmosphere/wind-speed-kt to 0

--prop:/environment/config/enabled=0
--prop:/environment/atmosphere/temperature-deg-sea-level=15
--prop:/environment/atmosphere/pressure-inhg-sea-level=29.92126
--prop:/environment/atmosphere/wind-speed-kt=0

Related content

• Turning off turbulence Topic on the official forum.