https://youtu.be/7H_xh7pd8OA Many small windup toys use a "runaway escapement" mechanism to regulate the spring energy rate of dissipation. The escapement mechanism consists of two parts; the escapement wheel and the pallet. The escapement wheel is driven by the spring motor and without the pallet will allow rapid depletion of the spring energy. With the pallet, the escapement wheel must rock the pallet back and forth which slows the depletion rate of the spring energy thus providing a longer running time. "A 3D Printed Windup Car Using a "Runaway Escapement" Speed Regulator" uses the same mechanism to increase the runtime of the car allowing it to complete a circle or two before the 3D printed spring is depleted. As usual, I probably forgot a file or two or who knows what else, so if you have any questions, please do not hesitate to ask as I do make plenty of mistakes. Designed using Autodesk Fusion 360, sliced using Ultimaker Cura 4.12.1 Engineering profile, and 3D printed in PLA on Ultimaker S5s.