Uniform circular-motion model
Fan Blade Radial Inertial Force Calculator
Calculate the centripetal-force magnitude required for a blade mass represented at its radial centre of mass. Bearing unbalance, blade stress and allowable speed are deliberately not inferred.
Ideal circular-motion results
NASA’s official circular-motion material gives centripetal-force magnitude F = mω²r = mv²/r. Here ω = 2πn/60, m is mass in kg, r is radial CG distance in m and n is rev/min. The supporting structure supplies an inward force of this magnitude; in a rotating frame the corresponding inertial term is outward.
Radial acceleration is a = ω²r. The displayed acceleration ratio uses the exact conventional standard gravity gn = 9.80665 m/s² listed by NIST; it is not local gravity and is not a stress or safety factor.
Tangential speed is v = ωr. CG speed and true outer-tip speed require different radii, so the latter is displayed only when an actual tip radius is supplied.
Vector boundary: multiplying one radial-force magnitude by blade count gives only a scalar sum of magnitudes. It is not the vector resultant on bearings. Identical evenly spaced rotating forces ideally cancel as vectors; actual unbalance requires every mass-radius product and angular position (plus other rotating components). This calculator therefore never reports a net bearing force.
No universal material-specific “safe tip speed” is given. Allowable speed depends on the complete impeller design, material/condition, geometry, manufacturing, joints, environment, inspection, applicable code and manufacturer analysis.
Bronnen: NASA circular-motion/centripetal-force reference; NIST standard gravity value.
