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Replacing the B-52 with an airliner bombtruck?

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  • Replacing the B-52 with an airliner bombtruck?

    When does the B-52 reach the end of its useful service? If so, what will be it's replacement as bombtruck? I've heard that one possibility is taking an airliner and putting bomb bay doors on the bottom and calling it good. What's the advantages and disadvantages of doing this? Can any airliner made today match the old B-52s airframe for getting lots of bombs onto target? Can an airliner do the same while costing the Air Force less money? Wouldn't servicing be easier since there already exists commercial airline maintenance for these airliners? Wouldn't it help airliner builders research and develop better airliners and bombers for the future? So I took at airliners. The Airbus A380F, Airbus A340-600HGW and the Boeing 777-200LR stand out.

    All three's Maximum operating speed is higher, Maximum Takeoff Weight is significantly higher, fuel capacity similar, though Range and Service ceiling are a little lower. In terms of Maximum Range, the 777-200LR and A340-500 can match the B-52. What about upgrading the B-52? Is it cost effective? Say replacing its P&W JT3D engines the with CFM56 turbofans found on the KC-135? Or even newer engines like the Engine Alliance GP7000 or Rolls-Royce Trent 980? You get 136,000lbf of thrust out of its eight P&W JT3D turbofans. When you can get 326,000lbf of thrust out of four GP7000 turbofans. Two of these would be enough to get the B-52 airborne! But could the wings handle them? Thoughts?
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  • #2
    This is an idea that has been looked at several times that I can recall. There are issues that make it not as attractive as it first appears.

    First, modifying the structure for a bomb bay is not a simple task. In addition to the doors you have to have sufficient back up structure to handle the bomb load weight. This load has to be spread over a significant portion of the fuselage which involves a major redesign effort. For example the cost to modify the 737 for the Navy’s P-8 Poseidon was substantial and that bay is relatively small compared to what would be required to have a bay which could handle a bomb load close to that of the B-52. Next you would need to modify the aircraft structure to handle the crew ejection system and back-up structure.

    Also, you would need to redesign the pressurization since on a bomber you do not pressurize to the same levels as a commercial aircraft. This is because you not want the explosive depressurization of the fuselage if you take a hit from any rounds fired at it. I could go on but suffice it to say that there are also several other areas related to absorbing incoming fire that would need to be made to the structure and the systems for the bomber mission.

    Finally, the cost of bomber aircraft is split up at about 30-40% structure and 60-70% cost of the systems. So the cost of the designing the basic structure is smaller than the avionics and avionics integration costs. In addition, the cost of the structural modifications to a current airliner would likely be close to the cost of a new design.

    While you can obviously use an airliner as the basis for an AWACS or Multi-mission Maritime Aircraft, the bomber mission would require substantially more structural modifications.

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    • #3
      The mighty B52 has been flying for about 50 years and the last I heard it was scheduled to be in service for up to 50 more which must make it the longest serving airframe design in history.

      I can only imagine that since it was designed as a flying bomb bay there are still no real compeitors. As for the operational reasons why the B52 beats a modified Boeing 777 with a cargo configuration tail ramp I have no idea. A 777 can stay up for well over 18 hours without refueling and with its big fat body it could hold all kinds of interesting stuff.

      Taking a bit of a guess I would say that a B52 is pretty basic in terms of construction so is easier to maintain comparred to a modern airframe which is a bit of a thoroughbred and, I would assume might take more maintenance effort to keep it flying.
      What would Occam say?

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      • #4
        By the time you redesign an airliner to be a bomber, it's not the same plane. The mission is completely different. Therefore, it's better to start from scratch and no compromise is required in the implementation.

        If you study your aircraft design it's notable that most bombers are "high wingers" (wings are attached to the top of the fuselage), not "low wingers". With a high wing, the plane and bombs are basically hanging from the wing. This makes for a very stable aircraft which is important for a bomber to be accurate. It also makes the plane more stable when the bombs are dropped. During a bomb drop, the weight of the plane and it's center of gravity (CG) can change abruptly and dramatically. Low wing planes would suffer stability problems in this situation.

        Fighters are generally "low wingers" (or mid wing). Putting the CG above the wing makes the plane more nimble. Turn rate is increased and the plane can change attitudes more easily.

        In summary, low wings are bad for bombers so converting commercial aircraft to be bombers is a "fail" from the very conceptual stage. Likewise, any purpose built aircraft will always be superior to any kludge because it can be optimized for it's function.
        Battles are dangerous affairs... Wang Hsi

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        • #5
          Yep....you can't really convert an airliner to a bomber. Now something like the C-17, another high wing monoplane with a lot of the necessary avionics and a good load capacity is something different. Wouldn't surprise me if the B-52 was replaced with a manned or unmanned bomb-truck based on that successful platform.
          Tacitos, Satrap of Kyrene

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          • #6
            until now everybody here agreed in the impossible conversion of an airliner in to a bomber aircraft. but none thought on the second propose: changing B-52's engines. i think with new engines, it could stay in service for 50 more years or so. the only doubt i have is if install the GP 7000 or R&R trent 980, the engines would have enough space between engine bottom and ground. B-52 wings flex a lot in flight and take off/landing. i think this is the most economically alternative for USAF, since acquire new bomber aircraft would take years testing, and money that USAF haven't. hot rodding the old BUFF is the way to go!

            _________________________________________________
            Hard work spotlights the character of people: some turn up their sleeves, some turn up their noses, and some don't turn up at all.
            Sam Ewing

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            • #7
              The B-52 airframe has little that a simple airliner airframe couldn't replace

              I flew B-52 G models in the mid to late 80s, when it still had a low altitude penetration roll (for which it was not well suited). On the pro side of the argument; I see no structural of performance reason that the right airliner couldn't fly the the B-52 mission. When maxed out on fuel a B-52h will probably fly about 8000nm with reasonable reserves, but the bombload at that fuel load is very small (perhaps 10,000 lbs). A 777 or netter yet a 747 or even 787 would have similar range with many times more bomb load. 747-8 could carry 100,000+ lbs over the max range of a B-52, burning not much more fuel. The 787 would carry a bit less than the 747 but it would still be several times more than the b-52 and the 787 would burn substantially less fuel. Any airliner would have a airframe life many times longer than the b-52 (originally designed for 5000 hours, then extended to 10,000 then 15,000) but at great cost and with some pretty beat up looking fuselage skin. An airliner needs dramatically less maintenance and has airframe life measured in 100s of thousands of hours.

              In addition, a B-52 is extremely fatiguing to fly due to the unbelievably high noise level, poor presurization, and nowhere to eat rest or even take a decent dump. Having a quieter, more comfortable aircraft would make the very long missions much less stressful (and there for more likely to be successful). The cost to fly and maintain would be much lower as well. Structurally the B-52 was standard 2 g airliner spec. except the b-52 was designed for a much lower fatigue life. The B-52 was never designed for low altitude work and this mission profile isn't even practiced anymore, partly because it was very dangerous, partly because it was hard on the remaining airframes, but also because the low altitude mission was no longer considered to be survivable.

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              • #8
                There really isn't any reason a modified airliner or cargo plane couldn't be used in the role of the B-52. The US Navy has and is using modified airliners as maritime patrol aircraft.
                I see no reason why an airliner couldn't likewise be converted to a bomber.

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                • #9
                  I like this idea, a 747 with 72 cruise missiles.

                  http://www.g2mil.com/bm747.htm

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                  • #10
                    and whatever happened to the low cost alternative called the B1?
                    Human beings are the only creatures who are able to behave irrationally in the name of reason.

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                    • #11
                      Originally posted by captbilly View Post
                      I flew B-52 G models in the mid to late 80s, when it still had a low altitude penetration roll (for which it was not well suited). On the pro side of the argument; I see no structural of performance reason that the right airliner couldn't fly the the B-52 mission. When maxed out on fuel a B-52h will probably fly about 8000nm with reasonable reserves, but the bombload at that fuel load is very small (perhaps 10,000 lbs). A 777 or netter yet a 747 or even 787 would have similar range with many times more bomb load. 747-8 could carry 100,000+ lbs over the max range of a B-52, burning not much more fuel. The 787 would carry a bit less than the 747 but it would still be several times more than the b-52 and the 787 would burn substantially less fuel. Any airliner would have a airframe life many times longer than the b-52 (originally designed for 5000 hours, then extended to 10,000 then 15,000) but at great cost and with some pretty beat up looking fuselage skin. An airliner needs dramatically less maintenance and has airframe life measured in 100s of thousands of hours.

                      In addition, a B-52 is extremely fatiguing to fly due to the unbelievably high noise level, poor presurization, and nowhere to eat rest or even take a decent dump. Having a quieter, more comfortable aircraft would make the very long missions much less stressful (and there for more likely to be successful). The cost to fly and maintain would be much lower as well. Structurally the B-52 was standard 2 g airliner spec. except the b-52 was designed for a much lower fatigue life. The B-52 was never designed for low altitude work and this mission profile isn't even practiced anymore, partly because it was very dangerous, partly because it was hard on the remaining airframes, but also because the low altitude mission was no longer considered to be survivable.
                      Cool insites on the B-52, and thanks for the post. I have only seen one low level pass made by a B-52 2 years ago, and the noise level was very high, and then the aircraft went to full throttle and dissappeared into the clouds in what seemed like only a few seconds. Amazing power from those engines!

                      good points all the way around...
                      ...Its one of our V-8's...Pursuit Special on methane, super hot!

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                      • #12
                        What about a combined C17 transport/bomb truck, or something along those lines.

                        For example, the C17 has a reasonable self defense capability from SAM's.

                        It flies to combat areas, although not necessarily above them....yet.

                        With laser guided bombs, I think it would be quite feasible to just slide them out the ramp from altitude with a parachute for stability, as from altitude precise weapons release shouldn't be critical.

                        The "cargo hold" section would need to be depressurised for altitude release.

                        No need to have a dedicated bomb bay, a la B52/B1, but it will need it's own laser target designator which won't be any problem.

                        What's 10x 2000lb GBU's to an aircraft that has a payload of over 150,000lb?

                        Of course, it would not be used for low and fast sorties, or unescorted where there would be a risk of fighter intercept.

                        The C17 production run is nearly over, and it will be in service for some time.

                        The B52 will also be in service for some time.

                        At the right time, kill two birds with one stone by producing a dual role transport/bomb truck, not necessarily based on the C17, but on something similar.

                        I think it would even be capable of fulfilling both roles on the one sortie, provided the bomb payload was sensibly loaded to avoid CofG issues on release.

                        Save heap$$$$ without sacrificing either capability in any significant way.

                        The last point is going to become vital, and imperative, in the decades ahead.
                        Last edited by At ease; 25 Mar 13, 10:21.
                        "It's like shooting rats in a barrel."
                        "You'll be in a barrel if you don't watch out for the fighters!"

                        "Talking about airplanes is a very pleasant mental disease."
                        — Sergei(son of Igor) Sikorsky, 'AOPA Pilot' magazine February 2003.

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                        • #13
                          The B-52 is still viable, and will be in service until at least 2045...leave it alone.

                          To even get something started now, from scratch would be 1 trillion or more in cash, that the USA doesnt have!
                          ...Its one of our V-8's...Pursuit Special on methane, super hot!

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                          • #14
                            Buff memories

                            When I was a kid growing up summers on the short seacoast we regularly had flyovers due to our proximity to a SAC base 10 miles north in Portsmouth. Any hour of the day (or night) we'd have to raise our voices to be heard over the noise of the B-47s and B-52s circling to land or take off. The bombers would be flying so low that we thought that we could actually see the pilots waving at us. I seem to remember that one or both aircraft would deploy a parachute on approach maybe to slow it or stabilize it in slow flight. They were HUGE ! To know that they're still flying those aircraft is amazing.
                            ARRRR! International Talk Like A Pirate Day - September 19th
                            IN MARE IN COELO

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                            • #15
                              Originally posted by Hetzer 15 View Post
                              The B-52 is still viable, and will be in service until at least 2045...leave it alone.

                              To even get something started now, from scratch would be 1 trillion or more in cash, that the USA doesnt have!

                              Amen Amen...........

                              Leave it alone. We don't have the money and besides the Buff still scares the S*** out of the bad guys.

                              Long Live the B-52
                              God Save The Republic.

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