A DC commutator motor that is driven by a direct current power source obtained by rectifying an alternating current power source includes a plus-side brush made of material having a high resistivity and a minus-side brush made of material having a low resistivity. 1 \u03bcm to 20 \u03bcm, wherein the composition is in the form of particles with an average diameter from 25 \u03bcm to 1 \u03bcm, wherein the ratio by weight of calcium lactate to calcium citrate, based on the dry weight, is 80:20 to 30:70, and wherein the calcium lactate is a non-polymeric agglomeration agent for the calcium citrate microparticles. The legs allow the height and span of the craft to be varied.