I'll chime in as a structural engineer: Huggy is right. It's not that big a deal.

Data point--BUFF is older, spent years flying a much harsher regime, still doing the job just fine. Whatever shortcomings it may have, nothing to do with the aircraft structure. And in fact, we keep hanging stuff on there that wasn't even dreamed of when the plane was built/plumbed. And it just keeps trucking along.

I got no inside game on the GH, but knowing the focus on weight, and the extremes it operates at, I'd be a little more worried about it's structural longevity than the U2.

There was an ariticle a year or two back when the AF tried to punt the GH, showed operating costs--Huggy do you still have it? I couldn't find it.

I don't have it handy. However, there are umpteen other versions too. "Cost" really varies, it seems. Each version has different "inclusions".

To qualify that statement, can you tell me what is rebuilt on the Buffs, approximately how many hours they have, approximately how many "rebuilds" they have on the sections, etc? Again, I kind of fail to believe these B52s have had nothing more than a few hot section replacements...

U-2 -vs- Global hawk
 

James, I know of no major structural repairs on BUFF. Depending how you define 'major,' frequently the AF answer is to park them when there are things like wing box issues. Just too expensive to fix. There has been cash spent upgrading capacity and systems, not sure if that is what you meant.

I work with some folks who will probably know the answers and will ask them later in week when I see them.

Out of curiosity, why the concern?

I've never heard of major structural programs for the BUFF either. Back in the day, before massive computer processing power was available they designed things with slide rules. So they avoided complex, difficult-to-calculate structural geometry and added a little extra beef just in case. Basically built sturdier.

When you try to eek out every bit of performance per ounce of structure you cut margins thinner, and modern computational methods give you a warm fuzzy doing that but there's often some missing factor that prevents the math from catching every possible weakness...and the real world will expose that eventually.

If you needed a truck to last for 50 years, would you rather have a 1955 chevy or a modern ford will alloy frame, etc?

Because I suspect massive amounts of money go into things like the B52s to keep them flying. Being a viable platform isn't the same as being "cost free once produced", which almost nothing is, but I'd imagine that most of the B52s and even U2s have had major overhauls and upgrades, making the cost huge over the years. Again, may still be viable and cost-efficient compared to designing and building a new plane, or just building a new example of the same plane, but I've got to think that UAV technology will keep pushing on and it won't be long until something easily surpasses the U2, if the GH doesn't quite fill it's shoes right now. It's probably the right time to invest in that, rather than expect to push something for 50 more years that will put people in harm's way and require vast amounts of money.

I live next to the sea, so that 1955 truck would be red dust now.

A fatigue-life part in the BUFF is some sort of "Wing clip," which was frequently touted as a success story for AMARC (the boneyard at D-M).

I believe the "Clip" is a major structural component that ties together the wing boxes in the fuselage.

On tours of the boneyard, the AMARC guide would tell how early model BUFFS would have the part salvaged, and installed on the current fleet, as it was otherwise unavailable, and without it, the aircraft were unflyable.

I'm not sure if the current fleet of B-52Hs are included, but earlier models I know were beefed-up with reinforcing straps along the bottom-side of the fuselage (almost the full length of the fuselage), due to higher stresses from flying low-level penetrations (the airplane was designed to be a high-altitude bomber).

A similar beef-up was done to T-38s about 25 years ago, closer to the top of the fuselage, for fatigue resistance.

Other than that, I know of no major structural work on the B-52H. KC-135s had lower wing-skins replaced in the 1980s; I think they are about to do it again. Don't think that has ever happened with the BUFF.

In the grand scheme of things, I think your "massive amounts of money" is a lot less than procuring a clean-slate system.

Same reason GA pilot still operate 40+ years old cessnas...why not just buy a new one? It's only $350K at the entry-level...

One thing you may be missing is the role the BUFF and U2 play...they no longer penetrate the the contested airspace of a near-peer opponent. The BUFF today is basically a high-altitude bomb truck, it can fly like an airliner and dump self-guided bombs with little or no maneuvering required. Why spend billions on a maneuverable, fast, and/or stealthy platform when all you need is a dump truck?

U2 is similar, not suitable for contested airspace (as Gary Powers learned so long ago) but lots cheaper than an aircraft which could penetrate...satellites largely fill the later role, as the SR-71 found out.

UAS are not ready yet, ESPECIALLY for the USAF. The navy brings it's own airport but the AF depends on basing rights in numerous other countries, not one of which has approved routine UAS ops in regular airspace. It's as simple as that, if it's hard to get approval to fly the things when and where you want them then manned is better.

The SecDEF just announced they will shut down U2 operations in favor of the Global Hawk. Big mistake in my opinion. That will leave the US with three high altitude (above 60,000') reconnaissance capable platforms (WB57F)and they belong to NASA.

U-2 -vs- Global hawk
 

U-2 cool

RQ-4 uncool

That's how you base a decision.