The U.S. Air Force is taking a serious look at reengining the Boeing B-52. The question is not whether it makes sense, but why it hasn’t been done. The answers include poor planning, budgetary procedures that defied economic logic and at least one bone-headed accounting error.
Putting new engines on the Buff, or Big Ugly Fat (cough) Fella, became a possibility after 1978, when the commercial business launched two modern powerplants that would fit a four-engine Buff: the Rolls-Royce RB.211-535 and Pratt & Whitney PW2000. Pratt published a study in early 1982 that showed the reengined airplane would fly farther and need less tanker support.
But in 1982 the Air Force expected to replace all of its bombers, well before 2000, with 100 B-1Bs and 132 Advanced Technology Bombers (ATB); and gas was cheap. The idea went nowhere.
Within another decade, the ATB—the B-2 stealth bomber—had been cut back to 21 aircraft, the B-1B had been shorn of its cruise-missile armament under the first Strategic Arms Reduction Treaty, and the B-52 was going to be around for a while longer. This time it was Rolls-Royce, which had just acquired a U.S. military foothold in the form of Allison, that proposed leasing RB.211-535s to the Pentagon, reducing the upfront investment.
Legal problems with the lease deal were one reason for the proposal’s failure. It was a sign of a deeper and as yet unsolved problem: Budget rules often run counter to common sense. Corporations and even people decide every day to spend money today on energy efficiency, calculating the payback period. In the Pentagon, procurement and operations budgets for weapon systems are separated by a near-unbreachable wall. It’s easier for the Air Force to spend money on golf carts for on-base transport, or solar panels for the O-club roof, than to put new fuel-saving engines on its aircraft.
Her en BUFF med fatigue wrinkles på det amerikanske museet på Duxford 2012 - Foto:
Per Gram
Sjekk denne videoen fra landingen på Dux: http://tinyurl.com/ygs2nv4
 
But as a Defense Science Board (DSB) task force on the B-52 reengining proposal reported in 2004, the Air Force also made an elementary mistake. It had assessed the payback period using fuel prices on the ground, and overlooked the fact that fuel coming out of the back end of a KC-135 was a little more expensive. Fifteen times more expensive, to be exact. The DSB recommended that the Air Force proceed with a new engine immediately, a suggestion that vanished without a trace in the service bureaucracy. The same fate overtook a National Academy of Sciences (NAS) report in 2009 that recommended new engines for the B-1B and E-3 Sentry as well.
The economic case for reengining the B-52 should in theory have become weaker in the decade since the DSB report, given that the retirement date has not changed, but the reverse has happened. Newer engines burn less fuel, and that fuel costs more. The maintenance cost of the wheezy old TF33 has soared past Air Force predictions, possibly because it’s not just a matter of nobody making TF33s any more; nobody makes engines that even look like TF33s. Today’s new engines are designed to stay on the wing so long that they will never be removed routinely until the B-52s are retired.
The technical risk is manageable. There have been questions about the engine-out characteristics of a four-engine B-52, but if that issue cannot be solved there is an eight-engine option with General Electric CF34-10.
Do some generals worry that upgrading old airplanes weakens the case for new ones? That would not be logical, even though stories of pilots flying their grandfathers’ bombers make good copy. The longevity of combat aircraft is a good-news story: Since today’s B-52s rolled off the Wichita production line, the Navy has launched and scrapped two classes of destroyer and four cruiser classes, and that comparison makes a $550 million Long Range Strike Bomber look a little more digestible.
Operationally, the case for extending the B-52’s life is at least as strong as ever. The decision to rebuild the Triad (AW&ST Sept. 29, p. 14) includes a new long-range cruise missile. In the Air-Sea Battle concept, the idea that B-52s carrying Lockheed Martin’s Long-Range Anti-Ship Missiles could be almost anywhere, able to hit your ships while staying far out of range of missiles or even carrier-based fighters, will concentrate an adversary’s mind wonderfully. And when a hypersonic strike weapon is available, what better platform than an aircraft that was built to carry a Mach 14 weapon, the AGM-48A Skybolt? 
The B-52 is not the only aircraft that might need a new powerplant. The 2009 NAS report also pointed out that the C-17 is the Air Force’s biggest fuel user, and that its early-1980s engines could benefit from a technology infusion. If the E-3 is not to be replaced before 2030, a CFM56-7 installation would be relatively easy. The challenge is to make sure that common-sense, valuable opportunities don’t fall through the cracks again. 
A version of this article appears in the October 27 issue of Aviation Week & Space Technology.