Air Force mapped targets for destruction with a failed airliner
By Miriam Adler ·
Potential targets and their subsequent destruction were mapped from 40,000 feet by a flying laboratory the public believed was simply an aesthetically appealing aircraft.
It was a 325-foot-long strip of film. It contained 390 individual photographs, capturing a 490-mile-wide field of vision. This was the output of a single flight on September 1, 1948, when a plane took off from Muroc, California, climbed to 40,000 feet, and flew east across the entire United States to land in Long Island.
According to a program description from the FAS Intelligence Resource Program, this aircraft was the XR-12, though it began its life as the XF-12. To the public, it was the "Rainbow," a plane with "aesthetically appealing lines" and a streamlined fuselage that made it look more like a piece of sculpture than a weapon. But the beauty of the Rainbow was a mask for a specific, cold utility.
"Flying on all fours"
The public record identifies the Rainbow as a four-engine, all-metal prototype designed for maximum aerodynamic efficiency. In the trade, this was called "flying on all fours": four radial engines, a 400 mph cruise speed, a 4,000-mile range, and a ceiling of 40,000 feet.
But before it was a tool of the state, the Rainbow was meant for the civilian. It was originally envisioned as a transatlantic passenger plane for Pan American World Airways. It failed in the commercial market for a banal reason: it only held forty-four passengers. It was too small for the airlines, but it was exactly the right size for the Army Air Forces' appetite for sight.
As World War II progressed, the military realized that the ability to make "pivotal strategic decisions" depended entirely on the speed and accuracy of intelligence gathering. The Rainbow was repurposed. It ceased to be a vessel for travelers and became a "flying photographic laboratory." The transition was complete when the USAAF became the United States Air Force in 1947 and the XF-12 was redesignated as the XR-12.
Document imagery from irp.fas.org From the files: irp.fas.org
18 High-Intensity Flash Bulbs
The Air Force didn't just want a camera in the sky; they wanted an industrial process at 45,000 feet. The XR-12 was outfitted with "complete dark room facilities," allowing crews to develop and print films while still in flight. The fuselage was a dedicated space for the gaze, featuring three separate photographic compartments.
For the hours when the sun failed, the aircraft carried a large hold in its belly that accommodated 18 high-intensity photo-flash bulbs. This allowed for night photography, ensuring that no territory remained hidden by the dark.
When modified with "all weather" equipment and a power plant capable of short bursts of extreme power, the XR-12 became, in the eyes of the State Department and the Air Force, a "potent intelligence weapon." Its mission was not just observation, but a calculated cycle of violence: providing "pre-strike photo interpretation of potential targets and the post-strike analysis of their subsequent destruction."
Operation Bird's-eye
This capacity for total visibility was most evident in the aircraft's intended use in the north. Operating from bases in Alaska and Canada, the XR-12 could map broad stretches of the Arctic regions. The FAS record notes that in these regions, the plane performed reconnaissance with "near-invulnerability."\
There is a particular kind of power in that word—invulnerability. It describes a state where the observer can see everything while remaining unseen and untouched, a one-way mirror held over the top of the world.
To demonstrate this power, the Air Force conceived "Operation Bird's-eye." On that September day in 1948, the second XR-12 flew from Muroc to Mitchel Field in Garden City, Long Island, in six hours and 55 minutes. The resulting filmstrip was treated as a trophy. It was featured in the November 29, 1948, issue of Life magazine and exhibited at the Air Force Association Convention in New York City. The public was invited to admire the grace of the aircraft and the scale of the images, likely unaware that the plane was designed to analyze the ruins of targets.
Mitchel Field
By the time the Rainbow landed at Mitchel Field and its record-shattering flight was being celebrated in magazines, the Air Force had already canceled the program. The Rainbow was a victim of its own timing and the availability of B-29 and B-50 aircraft, which could suffice for long-range reconnaissance until the RB-47 entered service.
The FAS record suggests a counterfactual history: had the Rainbow been available in 1944, it might have been ordered in quantity, potentially altering the postwar aircraft market and establishing Republic Aviation as a major builder of airliners. Instead, the Rainbow "disappeared into oblivion."
It left behind a fragmented paper trail. The US National Archives still holds photographs of the activities, facilities, and personnel associated with the program. Related diplomatic cables exist in the State Department's FRUS files, including a September 1974 telegram sent to diplomatic posts. The actual aircraft may have vanished, but the records of its "near-invulnerability" remain.