UB.109T was a British cruise missile project calling for a system able to deliver a 5,000 lb (2.27 tonne) conventional warhead over 465 miles (700 km) travelling at 600 mph at 50,000 ft (15,000 m). Guidance would be by Decca or LORAN. The specification for production was for plastic construction.
By cancellation, the Vickers 825 had reached prototype stage. The 825 was 13 m (42 ft 8 in) long with a 10 m (32 ft 10 in) wingspan. The airframe was welded and formed mild steel sections. The fuselage was rolled steel and the wing sheet steel over box spars. The wing served as the fuel tank. The three Soar engines were used, two on the tips of the tailplane, and one on the tip of the fin. The leading edges of the tailplane and fin were sharply swept, but the wing was straight and held to the fuselage by bombslips. The warhead (a single 5,000 lb (2,300 kg) bomb, or five 1,000 lb (450 kg) bombs scattered laterally) was held on the front of the fuselage by explosive bolts. In use, the wing was jettisoned at the target, and the warhead detached once the fuselage had stabilised in a dive and the altitude came below the radar horizon (20,000 ft (6,100 m) at 400 nmi (740 km; 460 mi) from its launch position). After initial guidance by flux gate compass and vertical reference, guidance was by the 'TRAMP' system of pulses transmitted from two ground radar stations, producing target position as the intersection of two range measurements. Guidance accuracy at a 400 nmi (740 km; 460 mi)-range target was specified as 100 yd (91 m) CEP.
One-third scale models without engines were built and air launched from a Washington bomber (the Boeing B-29 Superfortress in RAF service) on the Woomera missile range to test the aerodynamics and autopilot operation.
Cruising at Mach 0.83 at 50,000 ft (15,000 m), intercepting Red Rapier required surface-to-air missiles. This is in contrast to the wartime V1, which flew at low altitude and could be intercepted by existing fighter aircraft, or shot down by antiaircraft guns.
Full details of the Red Rapier project are given in The 'Secret' World of Vickers Guided Weapons by John E. Forbat and published in 2006 by Tempus (now The History Press).