The effect of the stinger assembly’s lateral stiffness on the overall system is very dependent on the stiffness of the structure being tested. If the structure itself is very stiff, then this is often not a serious concern. However, when the structure is very flimsy or has a significant amount of rotational effect at the attachment point of the stinger, then these lateral loads can become very important and a source of large measurement error. In addition, these rotational effects generally become more important at higher frequencies, so it is always difficult to determine that actual impact on the overall results. One easy way to determine the stinger lateral and rotational effects is to make several test runs with the length of the stinger varying by ±10% and observe the change in the measured drive point frequency response. Reference 5 provides a good overview and comparison on stinger types and effects on measured FRFs.