#b 29

FIFI is a surviving Boeing B-29 Superfortress, and one of two that are currently flying, the other being Doc.

'THE BOMBERS'

B-29 “DOC”

Does this airplane look familiar? It might, it's a B-29, the United States' most advanced heavy bomber of World War II. Except, not really. The red star is a little bit suspicious; it's a Soviet plane. But maybe it was given to the Soviet Union under Lend-Lease? Nope, the US refused to let anyone else have the B-29 due to all the brand-new tech it contained, such as a pressurized fuselage (allowing a higher flight ceiling) and an early computerized turret system. They wouldn't even allow it to be used in the European theater for fear of Germany studying one.

Well, this is a Tu-4, entirely of Soviet manufacture. In 1944, four American B-29s made emergency landings/crashes in the Soviet Union. One was returned (along with its crew) to the US after the end of the war, since the Soviet Union was officially neutral in the Pacific War, but the other three were kept. Funny arrangement, but it meant they had an official reason to intern the planes.

Those three B-29s were extensively worked over to learn everything about their design. One was taken apart entirely, another used for flight testing, and the third kept as a reference. The Soviet Union itself didn't have a usable heavy bomber design, so the Tu-4 had the chance to be a massive advancement. Even where the Soviet Union had better parts already being manufactured, high command tried to insist exact copies from the B-29 be made.

The reverse engineering wasn't easy. Everything on the B-29 was in imperial measurements, down to the thicknesses of the sheet metal on the skin. Changing it out for metric thickness materials meant absolutely every part of the math on stress and strength had to be redone. It almost feels like as much work as just making a new design. Still, the new Tu-4 ended up being only 1% heavier than the original.

They also made an extremely-cursed-looking passenger variant, the Tu-70:

The entire process took about three years from initial acquisition of the B-29s to its first public appearance in 1947. And what an appearance it was! At a parade/airshow in Moscow, three Tu-4s flew over the crowd. Western journalists figured they were the original three B-29s, just repainted and put back into service. But then a fourth one appeared. Hmmm.