The Run Amok Spinner Weapon Calculator performs several functions to aid a builder in the design of an effective spinning weapon. More advanced graphic analysis of spinning weapon performance is available from the Run Amok Excel Spinner Spreadsheet.

The Calculator gives the mass and moment of inertia (MOI) of a rotary weapon made up of tubes, disks, and rectangular bars of known dimensions and material densities - and the MOI of impactors of known mass and distance from the rotational axis.
The Calculator provides the kinetic energy storage and approximate spin-up time for the weapon when powered by a specific PMDC electric motor. The default motor speed and stall torque specifications are for an AmpFlow F30-150 motor at 24 volts.

Brushless Motor Stall Torque Estimate
Voltage: volts Speed: rpm
Kv: rpm/volt Torque: Nm
Ri: milliohm

Conversions between english / metric units are available in the section below the motor data inputs. Type a value into any field and click 'Convert' to obtain the value in the matching field above or below.
What do these numbers mean? How much kinetic energy is enough? How quickly should your weapon spin-up? Is crazy high RPM a good idea? See the Ask Aaron Spinner Weapon FAQ.