The Boeing B-29 was the most technologically advanced airplane program during WWII. At 105,000 pounds, it was the world's heaviest production airplane. The B-28 used state-of-the-art 2,200 horsepower Wright R3350 twin-row radial engines, each fitted with two turbosuperchargers. It was the first bomber with crew-cabin pressurization and remotely controlled power turrets. By production end, 3,970 B-29s had been built.