Energy of Fan Blade: Calculating Speed and Strength

[Colin De Bruy]

Thanks to all who posted. The fan was built by Universal Hovercraft it's purpose built for a small hovercraft designed for kids to ride on. The fan is driven by a 5hp petrol motor which has a top rpm of 3000 rpm. I doubt the engine will get to this rpm with the fan attached but at 3000rpm the tip of the fan is doing 339km per hour or 210 mph and the inner root of the blade is doing 169km or 105mph. So does anyone know how much energy a 200gram pine blade has if it were to break off at this speed? Many thanks Colin

 

[Cyrus]

http://en.wikipedia.org/wiki/Rotational_energy