1) The static compression, as specified in the aircraft.cfg, is used to calculate the spring constant used at runtime. It calculates it with an estimated gross weight including full fuel and the payload specified in the cfg. This is done because it is assumed that this will be the normal scenario in which it is loaded. The algorithm is simply:

K=EstGrossWeight / StaticCompression

Obviously weight and CG changes will affect the actual compression at runtime.

2) The Max/Static Compression really has nothing to do with the weight. It is simply a way in which we can tell the animation system what percentage of the total animation range the strut is compressed. It would be an incorrect assumption that this happens at max gross weight. At MGW you wouldn't want your gear fully compressed, as that would leave no more room to further compress. In other words, a very bumpy ride:). So, if the gear has a simulated compression of 0.5 ft at runtime, and the Max/Static Compression ratio is 1.5, the animation system would simply animate the compression 33.33% (0.5/1.5 = 0.33333) from fully extended.

One problem we've often encountered is that the range in the animation is sometimes less than the sim assumes. For example, if the compression in the model is less than 1.5 in this example, the animation will reach its limit before the sim reaches 100%. Similarly, if the sim comopression exceeds 100%, you may also see the wheel go under ground (for example heavy braking). We don't model any sort of rigid impulse force here, but rather let the spring naturally react. One can increase the spring constant by decreasing the static compression (see algorithm above), but then you may have too stiff of a gear. It's a tradeoff between the physical and visual effects you want to achieve.