The U.S. Air Force is thinking about replacing the late-1950s- era engines on its Boeing B-52 bombers with modern ones. It should have done that a decade ago, but back then, the Air Force believed that the cost of the new engines would barely be offset by the savings in fuel. This reasoning was based on the assessment that the cost of fuel wasn’t that high, but the service forgot that B-52s are voracious users of air-to-air refuel- ing. By the time the gas comes out of a KC-135 tanker’s boom, the delivery cost has increased by a factor of 15.

This planning deficit is nothing unusual. It would be a tribute to Boeing engineers’ advance planning that the BUFF (Big Ugly Fat, er, Fella) is due to keep flying until at least 2040, when the airplanes will be octogenarians...except that the longevity has been achieved despite the best that military planners could do.

The B-52 was nearly cancelled before a sliver of metal was cut. By the fall of 1948, Boeing had designed a swept-wing, tur- boprop-powered XB-52, but in October a Boeing team at Wright Field in Dayton, Ohio, was handed the bad news. Convair had just proposed hanging jet booster engines on the in-production B-36, erasing much of the XB-52’s speed advantage. But, the Air Force planners said, if Boeing could come up with an all-jet, long-range bomber....

That was on a Friday. Boeing’s team, led by aerodynamicist George Schairer and chief engineer Ed Wells, retreated to the Van Cleve Hotel in Dayton. On Monday, they briefed the customer on what was unmistakably the BUFF. (The only embellishment heard in this oft-repeated tale is that they designed it from scratch, when in fact they scaled up some features of the XB-55, a smaller bomber that was never built.) Before the stores closed, Schairer bought balsa wood, tools, paint, and glue, crafting a silver-painted display model that survives today in Boeing’s Chicago headquarters.

The Air Force planned the B-52’s demise again in the mid- 1950s, after Boeing had built about 450 of the bombers. The service was pursuing two replacements: a supersonic bomber burning boron-doped “zip fuel,” and a nuclear-powered air- craft. Neither went well, and in 1957 the Air Force signed on to Boeing’s stop-gap proposal for an improved B-52. Apart from a shorter vertical tail, the B-52G looked a lot like its predeces- sors, but its structure was lighter and its takeoff weight much greater, while integrated wing tanks replaced rubber bladders, boosting payload and range. It was designed to carry a pair of North American GAM-77 Hound Dog cruise missiles, which required heavy-duty pylons under the wings.

But even the B-52G was not the end of the line. Everyone other than the Air Force was becoming convinced that missilessiles, not airplanes, would be the future of nuclear deterrence. The bomber generals hedged their bets by developing Skybolt, a 1,150-mile- range, air-launched ballistic missile. The 20-ton total weight of four Skybolts called for more power, so the B-52H was given the engines from the latest 707 airliner. Unsurprisingly, the project did not go as planned. The last B-52H was delivered in October 1962, and two months later, the Skybolt was scrapped.

B-52s dropped iron bombs in the Vietnam War, and the G and H models were then modified to carry new-generation cruise missiles.The Air Force planned to replace them first with the swing-wing Rockwell B-1A, scrapped in 1977, then a combination of B-1Bs and B-2 stealth bombers.

The B-52G was retired in 1994, but only 21 B-2s were built. The B-52H flew on. No combat aircraft in the world has ever carried a greater load of weapons over a greater range, and the B-52 has wing pylons for long or bulky weapons that won’t fit in the weapon bay. Those two features provide the adaptability that explains the BUFF’s longevity.

In addition to looking at new engines, the Air Force is studying long-range hypersonic missiles. It’s a safe bet that if such a weapon makes it into service, the B-52 will be the first aircraft to carry it. Not bad for an old...fella.