Must not have been an H model
The H models (the only ones still flying) have much more powerful engines that previous versions. The engines on G model BUFFS produced 13,750 pounds of thrust each (but only with water injection) and the earlier versions produced even less, while the H model turbofan engines produce 17,000 pounds of thrust. I've heard that the crews can't apply full power on takeoff because it would overstress the wings.
B-52A specs.
B-52D specs.
B-52G specs.
B-52H specs.
Man, that puts those puny little 7,200 pound thrust engines on the B-47E or even worse, the 5,200 pound thrust engines on the B-47A in perspective. Talk about underpowered!