Based on the conventional coaxial coil secondary helical electromagnetic launcher (HEML), a new type of HEML with saddle secondary was proposed in this paper. The open geometry saddle secondary is mounted on the primary which fixed on the ground. The new spatial topology of system can provide long distance thrust acceleration. This feature is feasible to be applied to the device for ultra-high speed ground traffic. Its propulsion force characteristics were given by theory deduction and finite element calculation. A 2 m barrel x 120 mm inside diameter saddle-projectile HEML was designed, constructed and tested.

helical EM launcher， linear motor， series exited， saddle secondary