Hi all, is there any rule of thumb on exhaust size and lenght for a given fan? Is there any correlation between the exhaust outlet size and thrust? In the WeMoTec instruction sheet for the Mini Fan 480, the instructions say the exhaust tube should be 50-60mm long with the diameter being reduced from 69 mm down to about 60 mm. This tube is going in a Super Sniper and this short tube leaves a lot of fuselage between the tube end and the fuselage end. The end of the fuselage has an opening about 47 mm. I can increase the fuselage exit size by cutting back on the fuselage end. this would get me another 3 to 5 mm. Will this help? This may seem anal, but I try to optimize all the planes I build or assemble. Thanks, Rich