When I make a prop disc.... I...
* Make a disc, set Gizmo to be aligned with the scene world
* Set size, and then reset scale
* Click Animation Manager on and set KF's from zero to 100 for prop0_blurred animation name tag
* Open Attachment manager and click on Visibility and then find prop0_blurred visibility, click attach to Geometry.
* Close those
* Turn on Animation mode, rotate disc at KF 25 at 90 degrees of rotation (or slightly less), repeat for KF 50, 75, and 100. (Cannot be over 90 degress rotation). So thats 4 animations; 25, 50, 75, and 100 KF points, 90 deg's each.
* Compile a model and test in FS.
If you go over 90 deg's on each rotation, it will not work, as you cannot go over 360 degrees within 100 key frames.
Hope that helps.
NOTE: You must add a texture to this, click on Transparent on the Material editor if working in FSX/P3 for the prop to show up right in FS/P3.