Originally posted by ahnggk
It's not just the engines.

The shape of the aircraft is equally important as well..

The most advanced, cleanest, most fuel efficient engine fitted to a flying brick will certainly burn a lot more fuel than a very clean, very low drag design fitted even if fitted with WW2-era jet engines.

The fact that the B-52 while their old engines smoke a lot, they are more aerodynamically efficient than most modern jet airliners today using cleaner engines that's why the B-52 can cover the same distance, and probably burn the same amount of fuel.

edit on 25-1-2012 by ahnggk because: (no reason given)

Actually, the vast majority of efficiency savings come from the engines - the Boeing 787 has about a 20% increase in efficiency over the Boeing 767, with more than 15% of that efficiency gain coming from the engines alone - aerodynamics improvements these days count for single digit increases in efficiency.

The reason the B-52 has never been reengined is because the USAF is still sat on an absolutely huge stockpile of already purchased engines and spare parts - if you reengined, you would have to dispose of that stockpile and buy new spare parts, which vastly increases the costs of any reengining program.

Thats the sole reason the USAF rejected a proposal in the 1990s.