The preliminary SDK associated with the SU10 beta flighting includes new parameters for the flight model for spoiler lift and drag while in the air, while the existing spoiler lift and drag variables now pertain to ground operations (unless the in air spoiler lift and drag parameters are not used). I've been testing how these parameters work using the default A320 and have had some curious results.
I only investigated the drag effect, and to make sure the lift effect did not interfere in some way, I set the lift affect for both air and ground spoilers to -0.001. First, I looked at the spoiler drag on the ground. I set the ground spoiler delta cd to 0.001 and the in air spoiler delta cd to 0.1. I was surprised to see a Cd spoiler of 0.06109.
I then set the air spoiler delta cd to 0.001 and the ground spoiler delta cd to 0.1. Again, on the ground, I was surprised to see spoiler cd of 0.00006.
In the air, with the air spoiler delta cd set to 0.001 and the ground spoiler delta cd set to 0.1, the spoiler cd was given as 0.00006.
Swapping the delta cd values in the flight_model.cfg file resulted in a spoiler cd of 0.06109.
With the air spoiler delta cd set to 0.14 and the ground spoiler delta cd set to 0.15, the spoiler cd was given as 0.08552.
From these results, it looks like the air spoiler drag is being used both in the air and on the ground, and that the ground spoiler delta cd is not being used at all. (Note: I did go back and double-check that the gear is on ground simvar returned a "true" value for these cases.) It also appears that the spoiler drag value shown in the drag debug window is always 61% of the delta cd value in the flight_model.cfg file. Why is this?
As I said, I did not check the effects of the ground and air spoiler lift parameters, but I am concerned that they may also exhibit these issues.