The following report was filed by Robert Livingston of Slot Car News.
Les at Mainline Hobbies kindly sent us two samples of the new-production Rush 36k motor. The first version was tested by the Slot Car News Motor List staff at 36,600 RPM at 12 volts; with torque at 215 gcm/12v, about as close as you can measure to the specified value of 218 gcm. Overall power in the mid range of RPM (the maximum power band) was computed at 19.7 Watts, which is plenty powerful indeed. By comparison, a Slot.It long-can Boxer 2 puts out 18.3 Watts.
The new Rush 36k has cooling holes in the top and bottom of the case; these vents should allow the performance to stay strong for a longer time during a race. Heat in a motor increases current draw and lets the torque fall off, so heat is the enemy (especially in heavily loaded magnet racing, for which this motor would be well suited).
Both new test motors have balancing marks on the armature stack; one motor had blue epoxy applied to balance it. The other was evidently in balance and needed nothing. Both seemed smooth as they sang at full RPM.
No-load RPM tests of the two new sample motors resulted in 38,145 RPM at 12 volts for one motor, and 38,146 RPM for the other. These are average values for about thirty seconds of running, after a few minutes of warm up. Torque tests (an average of nine readings at stall, around a full rotation of the armature) showed a hefty 257 gram-centimeters for both motors. This is remarkable consistency for production-quality motors. The test motors are exceeding their specs (36,000 RPM, 193 gcm) by a considerable amount.
Maximum power output was computed at a whopping 24.5 Watts on 12 volts, in the mid range of both torque and RPM. Looking through the Slot Car News Motor List, only the 38k and 46k NSR long-can Kings produce more power. The Rush weighs only 22 grams, with long shafts on both ends; the Kings are 10 grams heavier, at 32 grams.
The new version of the 36k Rush motor is a bear. If you need high revs and LOTS of power, in a small, light package, this is your motor.
Thanks to Les at Mainline Hobbies for the chance to test these motors.