起落架平常是收起,稍微突出來有很好的流線型,在受到壓力(機腹著地),應自動用力彈出。pressure switch
In a hydraulic system, the pressure switch continuously monitors the process pressure and is activated when a specified pressure is reached. The pressure switch is responsible for activating or deactivating the hydraulic pump when the pressure threshold is met.
https://www.flowtech.co.uk/news/2022/september/how-does-a-pressure-switch-work/?