US Air Force upgrading B-52s

[Stitch]

Stitch,

Since your link on 747 bomber starts with costs... what is the cost of 747 compared to B-52? ;)

Rough estimates of "militarizing" a standard cargo B747-400F/ERF basically doubles the cost of the 747 to around $500 million each; interestingly, your basic B-52H is a bargain at $84 million per.

[Doktor]

Rough estimates of "militarizing" a standard cargo B747-400F/ERF basically doubles the cost of the 747 to around $500 million each; interestingly, your basic B-52H is a bargain at $84 million per.

Those are the numbers I have found, too. Thought there could be a mistake.

So, maybe it is better to "civilize" B-52 instead

[desertswo]

Personally, I like it! :)

[gf0012-aust]

Isn't there a B52 out at Davis-M which has had a single turbofan (ex 747 IIRC) installed in place of one of the inner twin pods?

They ran trials a few years back as part of a general eval.

[Chogy]

It's not just $$. Modern fans would increase the range, ceiling, and possibly TO gross weight as well.

The MD-80 has relatively modern engines. Fuel flow in cruise is 3,000 pounds/hour. A new 737-800 burns 2400 lb/hr per engine, and has greater thrust to boot. This is 1980's tech vs 2000's tech.

There is an enormous gap between the current BUFF and a set of modern engines.

[Jimmy]

Maybe the spares situation has changed, or maybe they're giving more consideration to performance and maintainability these days to make it a worthwhile venture.

The spares situation is the reason they'll never be reengined, nor AWACS/JSTARS. The C-141s (retired) ran TF33s. The KC-135As (retired) ran TF33s. The remaining KC-135 models (all reengined) ran TF33s. There are literally thousands of TF33 cores available.

Also remember the wings on the B-52 are quite low to the ground, especially for the outboard pylons. I don't think you're going to get a high-bypass modern turbofan on there without putting skid plates on the bottom of it!

IIRC a CFM56 fits on the inboard engine pylon, but not the outboard.

[gf0012-aust]

IIRC a CFM56 fits on the inboard engine pylon, but not the outboard.

that may well be the engine used on the test mule out at Davis-M

[gunnut]

Most likely; the main wing spar(s) go right through the BOTTOM of the fuselage, not the top, like on the B-52 (which is why the B-52 has a high wing, and not a mid- or low-set wing), so putting a bomb bay on a B747 would most likely be problematic, at the very least. I suppose you could put a forward and a rear bomb bay in a B747, but all that space in the middle of the fuselage would be wasted, unless you put another fuel tank right over the wing.

Good, fairly recent, article here about the B747 "bomber".

I was think about a new bomber using 747 or even 777's wing and engine, with the wing set high like B-52, and a new fuselage. It'll be more expensive than a conversion, but more purpose built as a bomber.

[JA Boomer]

Personally, I like it! :)

[ATTACH=CONFIG]33697[/ATTACH]

Doesn't look nearly as strange as I thought it would!

[JA Boomer]

Personally, I like it! :)

[ATTACH=CONFIG]33697[/ATTACH]

The 4 engine layout doesn't look nearly as strange as I thought it would!

[desertswo]

The 4 engine layout doesn't look nearly as strange as I thought it would!

Sort of grows on you doesn't it?

[Doktor]

Sort of grows on you doesn't it?

Me like it, too.

[Monash]

Yes, but how long can they keep "upgrading" these old airframes? I note the apparent success of the P-8 as a replacement for the PC-3. Could they modify a commercial design as a stopgap standoff "heavy" bomber pending final development of any new supersonic manned/unmanned replacement for the B-52 mid this century?

[gf0012-aust]

Yes, but how long can they keep "upgrading" these old airframes? I note the apparent success of the P-8 as a replacement for the PC-3. Could they modify a commercial design as a stopgap standoff "heavy" bomber pending final development of any new supersonic manned/unmanned replacement for the B-52 mid this century?

the problem with modifying a commercial design is not about whether they can find a decent flying airframe, but it revolves around the capacity of that frame to be modified for weapons carriage and release

eg most people look at the P8 and see it as a modified commercial platform, when in actual fact very little of it is commercial, there was a hell of a lot of effort into designing the weapons carriage and release section of the hull -in fact most involved with the prog regard it as a ground up effort

thats why a lot of the proposals to use 747's as missileers etc has failed a proper engineering analysis....

[JA Boomer]

Yes, but how long can they keep "upgrading" these old airframes? I note the apparent success of the P-8 as a replacement for the PC-3. Could they modify a commercial design as a stopgap standoff "heavy" bomber pending final development of any new supersonic manned/unmanned replacement for the B-52 mid this century?

A LONG time. The frames are structurally sound into the 2040's, and the B-52H currently is less maintenance intensive then either the B-1B or B-2A. It performs it's mission well, and it's still a mission that's needed (a non-stealthy heavy bomber may become obsolete in the future), so why not upgrade it.