aero/coefficient properties returning 0 about jsbsim HOT 1 CLOSED

You haven't given enough context. At what point are you executing:

Clp = fdm['aero/coefficient/Clp']

While the aircraft is flying or while it's standing still on the ground?

Now I presume you've seen this function in c172p.xml right?

Now the first thing you need to realise is that the name of the function can be anything that the FDM author feels like using, but typically people include coefficient names in the function but there is no requirement, you could name this aaa for example.

Now it turns out that functions using this sort of naming convention can be misleading, the description field gives it away, this isn't a function which returns a coefficient, it's a function that calculates and returns a moment, in this particular case by multiplying a number of fields and values together.

Now I'm guessing you're trying to retrieve the coefficient in particular, i.e. -0.4840 in this example?

If so, remember that coefficients in general aren't static figures. For example take a look at this example:

The coefficient in the above case is dependent on Mach.

What exactly are you trying to do?

from jsbsim.