Convert Horsepower to Torque at a specific RPM. Useful for automotive tuning and selecting motors for industrial applications requiring high starting force.
It's a conversion constant derived from units (33,000 ft-lb/min / 2π). It makes the math work for HP and lb-ft.
Because they spin at very high RPMs. Horsepower is a function of torque times speed.
T = 5252 * HP / RPM