Designated XF-12, when F stood for 'photo' in the pre-1947 system, and
later XR-12, the Rainbow was a high-speed high-altitude reconnaissance
aircraft, intended to scout targets over Japan for the B-29s. This may have
happened if the programme had started earlier, because when the war ended
with the atomic bombings, the first aircraft was only partly complete.
Republic still hoped to make the Rainbow into a 46-seat airliner, which they
called the RC-2. Their selling point was speed, for which customers would pay
a premium. Unfortunately, the expected postwar boom was not immediate
and the airlines bought the slower but roomier DC-4 and Boeing 377 instead.
An XR-12 was not delivered to the Air Force until late 1948, but crashed on
its second test flight. The other Rainbow was sent to a gunnery range.
FACTS AND FIGURES
� Each engine nacelle was as long as
a P-47 Thunderbolt.
� The tail fin design was later used in
reduced size on the F-84 Thunderjet.
� To fit inside the confines of the
laminar flow wing, the Rainbow had
large, thin, single wheels. One wheel
fell off after a hard landing but the
XF-12 was only lightly damaged.
� The Rainbow had its own
darkroom in order to develop
reconnaissance images on the way
back from a long photo mission.
Republic XF-12 Rainbow on YOUTUBE
Specification
MODEL
XF-12
CREW
5-7
ENGINE
4 x Pratt & Whitney R-4360 "Wasp Major", 2250kW
WEIGHTS
Take-off weight
45950 kg
101303 lb
DIMENSIONS
Wingspan
39.36 m
129 ft 2 in
Length
28.59 m
94 ft 10 in
Height
8.63 m
28 ft 4 in
Wing area
152.30 m2
1639.34 sq ft
PERFORMANCE
Max. speed
684 km/h
425 mph
Cruise speed
640 km/h
398 mph
Ceiling
13000 m
42650 ft
Range
7000 km
4350 miles
Comments
Charles Janczak, e-mail, 29.09.2012 16:40
The Rainbow is without a doubt one of the most beautiful aircraft ever built,Kartveli at his best.
It has been claimed that the Rainbow was the fastest piston-engined, 4-engine aircraft ever built. If it wasn't, it must have come pretty close.
The only other aircraft built to meet the same AAF requirement for which the Rainbow was built was Howard Hughes' twin-engine XF-11, which was the aircraft in which Hughes was nearly killed when he it crashed during it's maiden flight. In the end, the AAF didn't buy either of those aircraft because, by then, the war was over and they simply weren't needed.
Pan American World Airways seems to have expressed interest in this proposal. This would have been one of the most elegant airliners aside from the Lockheed Constellation to grace the skies: rides.webshots.com /photo /2501471570048918155xwsbOi
