A fluid jet loom suitable to perform a method of calculating timing of weft picking and a method of setting weft inserting condition

A method of calculating the timing of weft picking is applicable to a fluid jet loom provided with a weft inserting nozzle (18) which is supplied with a pressure fluid enabling weft inserting to be normally performed and jets the pressure fluid together with a weft (12) at the weft inserting time, and a weft engaging member (22) for controlling the weft length, the weft engaging member (22) being arranged on the side of a weft length measuring storage unit (16) and releasing the weft in response to the start of jetting the fluid from the weft inserting nozzle (18). The calculation method includes calculation of the timing for the weft to enter the warp shed based on the set values of the known weft inserting condition. The set values of the weft inserting conditions includes the jet start timing of the weft inserting nozzle (18), the weft release timing of the weft engaging member (22), and either the rotational number of the main shaft (36) of the fluid jet loom or the pressure value of the pressure fluid supplied to the weft inserting nozzle (18).