120mm 4" Ducted Bed Fan/Exhaust Fan

thingiverse

Parts to build a ducted bed fan for hot nights using a recycled 120mm computer fan and 4" flexible vinyl vent ducting. Alternatively, one or two of the reducer/coupler pieces can be used to connect a 120mm fan to 4" ducting or to mount a 4" duct to a 110mm circular cutout in a panel for building a fume extractor or inline exhaust blower. The fan's mounting holes are spaced at the corners of a square with 105mm sides. The intake piece includes a short intake trumpet to improve airflow and a grate to keep things out of the fan blades. The endcap piece also includes fins to straighten the air flow and give stiffness to the barbs the duct goes over. **Print all pieces upright with low infill and no supports!** **Update 7/21:** Tested fitting two of the reducer parts on either side of the fan and using the assembly as an in-line booster with lengths of tubing on either end: this configuration reduces intake noise further and improves air flow, but is bulkier as a result **Update 5/21:** Intake and reducer updated to v3, removed vertical fins as they were the main source of noise in the design and lengthened the intake bell mouth to prevent the fan from tipping over; v3 files were measured to be over 10db quieter on average at a distance of 12in **Update 4/21:** Intake, reducer, and endcap parts all updated to v2, all parts now include proper curved bell mouths that will better smooth air flow and reduce noise