XF-12 Rainbow

The XF-12 Rainbow was a four-engine, all-metal prototype monoplane designed by the Republic Aviation Company in the late 1940s. Like most large airplanes of the era, it used radial engines—in this case, the Pratt & Whitney R-4360 "Wasp Major"—to drive propellers.

The United States Army wanted a long-range photo-reconnaissance aircraft, and the Rainbow was Republic's attempt to provide it. With a cruise speed of over 450 statute miles per hour (725 kilometers per hour), it was certainly fast, but the Air Force (spun off from the Army Air Force in 1947) decided that the Boeing RB-50 would fill the need instead. As a result, Republic cancelled its plans to build not only the XF-12 but the RC-2 civilian airliner version as well, leaving only the two prototypes. One crashed leaving Eglin Air Force Base, Florida, and the other ended up as a target on the Aberdeen Proving Ground, Maryland.

Specifications (XF-12)

General Characteristics

• Crew:
• Length: 99 ft 9 in (30.39 m)
• Wingspan: 129 ft 2 in (39.37 m)
• Height: 28 ft 9 in (8.75 m)
• Wing area: 1,640 ft² (152.36 m²)
• Empty: 66,980 lb (30,382 kg)
• Loaded: lb ( kg)
• Maximum takeoff: 113,250 lb (51,370 kg)
• Powerplant: 4x Pratt & Whitney R-4360-31 radials, 3,000 hp (2,238 kW) each

Performance

• Maximum speed: 460 mph (740 km/h)
• Range: 4,100 miles (6,597 km)
• Service ceiling: 40,000 ft (12.192 m)
• Rate of climb: ft/min ( m/min)
• Wing loading: lb/ft² ( kg/m²)
• Power/Mass: hp/lb ( kW/kg)

Related content

Related development: Republic RC-2

Comparable aircraft:

Designation sequence: F-9 - F-10 - XF-11 - XF-12 - F-13 - F-14 - F-15