Rapier Weaving
The rapier head does not fail at top speed. It fails in the acceleration ramp, and that ramp gets steeper with the square of loom rpm.
— m/s²
On the acceleration ramp of a trapezoidal profile
A symmetric trapezoid is the simplest usable profile; real rapier drives are cam-generated and shaped deliberately to soften the handover, so peak acceleration on a well-profiled machine sits below this. The inertial weft tension is only the yarn being dragged — package unwinding, accumulator drag and brake tension all add on top.
Rapier Tape Stroke Acceleration Profiler — free, with the formula and a worked example, at Textile School.