Equal-length opposite-handed helices (${\Omega }_1=-{\Omega }_2=\omega /2,U=-B\omega /(2A)$)

Equal local resistance magnitudes and opposite coupling signs give ${\Omega }_1=\omega /2$, ${\Omega }_2=-\omega /2$ and $U=-B\omega /(2A)$. Translation-induced torques cancel, while propulsive forces add because handedness and rotation both reverse.