The ASL Viking was a single-engined two seater biplane aircraft designed and built by Horatio Barber's Aeronautical Syndicate Ltd. at Hendon.

The Aeronautical Syndicate Ltd. was an enterprise established by Horatio Barber in order to promote aviation in Britain.

The power installation was less commonplace, with a front-mounted 50 hp (37 kW) Gnome Omega rotary engine driving a pair of 8 ft 6 in (2.59 m) two-bladed wooden tractor configuration propellers mounted midway between the two wings on shafts on the inner interplane struts.

Lateral control was effected by a pair of mixed aluminium and steel ailerons attached to the rear interplane struts midway between the wings and spanning the outer two bays on each side.

The rectangular fuselage, which was mounted slightly above the centre section of lower wing, was a wire-braced mixed silver spruce and ash wood construction, tapering to a horizontal knife-edge at the tail.