Could the XB-70 Valkyrie be feasible today?

[JOE BRENNAN]

Originally posted by Burncycle360:

Most heavy transports are doing just that; transporting important stuff. That's a full time job.

 

Like many or most questions, subject to the comeback of "but that's not a real war" when discussing recent ops. But in many of those the peak load for transport (if any) and strike planes hasn't been the same. Where for example where air forces involved greatly outweighed ground forces (Afghanistan) or there were no ground forces (Kosovo) or there was a big ground build up first then an air war (Iraq wars). Timing and relative degree of workload on transports wasn't the same in each. Therefore some number of flexible BMACK type a/c could make sense I think. I think the Lockmart concept for a stealthy BMACK anyway doesn't imply not having lots of normal (much cheaper) non-stealthy transports © and tankers (K) also. But it might be viewed as a replacement for stealthy B's and non-stealthy SOF transports (M) and gunships (A).

 

Joe

[Burncycle360]

Like many or most questions, subject to the comeback of "but that's not a real war" when discussing recent ops. But in many of those the peak load for transport (if any) and strike planes hasn't been the same. Where for example where air forces involved greatly outweighed ground forces (Afghanistan) or there were no ground forces (Kosovo) or there was a big ground build up first then an air war (Iraq wars). Timing and relative degree of workload on transports wasn't the same in each. Therefore some number of flexible BMACK type a/c could make sense I think. I think the Lockmart concept for a stealthy BMACK anyway doesn't imply not having lots of normal (much cheaper) non-stealthy transports © and tankers (K) also. But it might be viewed as a replacement for stealthy B's and non-stealthy SOF transports (M) and gunships (A).

 

So what happens when "peak" load for transport and strike is at the same time?

[Smitty]

Originally posted by JOE BRENNAN:

I think the Lockmart concept for a stealthy BMACK anyway doesn't imply not having lots of normal (much cheaper) non-stealthy transports © and tankers (K) also.

 

Since "cheapness" is largely a factor of how many you buy, perhaps having an all BMACK fleet isn't such a bad idea.

 

Now from the sound of it, BMACK'll only be in the C-130 class, so larger lifters & tankers will still be necessary.

[Smitty]

Originally posted by Burncycle360:

So what happens when "peak" load for transport and strike is at the same time?

 

You're screwed either way.

 

In this situation, 100 BMACKs is no better or worse than 50 dedicated transports and 50 dedicated bombers of similar capability.

 

The only drawback would be if BMACK traded significant levels of capability in each of these areas for stealth and reconfigurability. Then, it might be preferable to have dedicated types.

[Ol Paint]

Originally posted by Burncycle360:

  How "big" is tooling exactly? I wish they required tooling for all aircraft stored in controlled conditions for a certain period at least. I've been told some tooling is purposely destroyed    

 

It can't be THAT expensive just to store can it?

 

 

<font size=1>[Edited by Burncycle360 (03 Dec 2004).]

 

It depends, but it can be very large since "tooling" includes the jigs and fixtures necessary to assemble the wings and fuselage, for example. In the case of the B-1, I would expect that the tooling preserved included things like the equipment necessary to create the wing hinge box. Covered storage would be extremely expensive due to the size of the tooling involved. However, they don't just pile the equipment into a dump truck and dump it in the desert. Keys and attachments are probably wired to their associated tooling and the tool is probably either shrink-wrapped or covered in spray-lat, just like aircraft stored at Davis-Monthan. The tooling is preserved until the DoD decides that they no longer need it (this decision CAN be political, as it appears to have been in the case of the F-14 tooling).

 

I tend to think that converting airliners or cargo aircraft to bombers is only worthwhile in an emergency, as in the postulated destruction of the entire heavy bomber fleet. Bombs are high-density items that would inefficiently utilize the volume of the typical airliner. ALCMs would consume more of this volume, but most airliner designs would have to have the bomb bays located outside the wing center section, which could pose longitudinal center-of-gravity issues (although this is not insurmountable, as demonstrated by aircraft like the Nimrod and P-3). In addition, airlift assets are generally well-utilized.

 

Douglas

[JOE BRENNAN]

Originally posted by Burncycle360:

So what happens when "peak" load for transport and strike is at the same time?

 

The question implicitly assumes unlimited resources. If limited resources can be saved with multipurpose assets, albeit with reduction in simultaneous peak capability, they can be used to bolster some other capability. If resources are unlimited of course buy everything in every category to cover all possibilities. You can't impose the boundary condition "what if 100% of both are required at the same time" to reject multipurpose assets with limited resources. You have to estimate how likely that is, to weigh it against the times you save resources by going multipurpose bomber/transports and can use the resources elsewhere. And as I said peak simultaneous demand for both seems quite unlikely based on experience and general principles.

 

Most of the time warplanes *and* transports will not be fully utililized at any given time in a conflict. Note too this is a comparative resource issue. Demonstrating that say just transports (at the proportion bought now) are always busy would not disprove the point. Which suggests some multipurpose types gives more benefit that loss. Usually (since 1930's remember Ju-52 bomber/transports?) the issue would be how technologically to have a plane that can do both at reasonable cost efficiency. Which is still unproven, nice pictures by Lockmart as of now. There'd naturally be training issues too like any multipurpose platform.

 

Joe

 

[Edited by JOE BRENNAN (06 Dec 2004).]

[Jeff]

The 747 was considered as a "bomb truck" in the 70's for hauling rather large numbers of ALCM's mounted internally on rotary launchers.

[Swift Sword]

Hi guys,

 

Given the cost of developing a supersonic bomber, might it not be worth a look at piggybacking an orbital bombardment system onto the NMD program instead?

[Garth]

One thing to note is that the B737 deriv. that the USN has selected as its P-3 replacement will have at least one, possibly two, internal weapons bays (I've seen concepts with a bay forward of the wing and/or a bay aft of the wing).

 

I'm not an engineer by any means, but my recollection is that older style airliners (B727 specfically) carried most of their passenger and cargo loads forward of the wing at something close to a 60-40 ratio (maybe even a bit higher than that). On a 727, a weapons bay forward of the wing a passenger/cargo equivilant load would be somewhere in the neighborhood of 17,000 lbs (189 passengers * .6 * avg weight of 150lbs). While not nearly what a B-1/2/52 can carry, that's not unsubstantial by any means.

 

--Garth

 

Originally posted by Ol Paint:

I tend to think that converting airliners or cargo aircraft to bombers is only worthwhile in an emergency, as in the postulated destruction of the entire heavy bomber fleet.  Bombs are high-density items that would inefficiently utilize the volume of the typical airliner.  ALCMs would consume more of this volume, but most airliner designs would have to have the bomb bays located outside the wing center section, which could pose longitudinal center-of-gravity issues (although this is not insurmountable, as demonstrated by aircraft like the Nimrod and P-3).  In addition, airlift assets are generally well-utilized.

 

Douglas

[BP]

Originally posted by Smitty:

Now from the sound of it, BMACK'll only be in the C-130 class, so larger lifters & tankers will still be necessary.

 

 

They still won't be able to haul a Stryker!

[Chris Werb]

The 747-400 Freighter (for instance) can carry 124 tons (113,000 kilograms) of cargo more than 4,400 nautical miles (8,230 kilometers) nonstop. Presumably there is a safe fuel reserve included in the above figure. I don't know what internal reinforcement or handling systems would be needed but I would be very surprised if the plane couldn't carry 100,000lb of ordnance. The balance issue might be addressed by pumps transferring fuel from tanks situated near the extremities of the aircraft.

[Ol Paint]

Originally posted by Garth:

One thing to note is that the B737 deriv. that the USN has selected as its P-3 replacement will have at least one, possibly two, internal weapons bays (I've seen concepts with a bay forward of the wing and/or a bay aft of the wing).

 

I'm not an engineer by any means, but my recollection is that older style airliners (B727 specfically) carried most of their passenger and cargo loads forward of the wing at something close to a 60-40 ratio (maybe even a bit higher than that).  On a 727, a weapons bay forward of the wing a passenger/cargo equivilant load would be somewhere in the neighborhood of 17,000 lbs (189 passengers * .6 * avg weight of 150lbs).  While not nearly what a B-1/2/52 can carry, that's not unsubstantial by any means.

 

--Garth

 

 

Which I acknowledged in my original post. However, the second issue is that you don't drop a dozen passengers at a time from an airliner while the aircraft is in flight, so the loads remain fixed and can be easily balanced before the aircraft ever leaves the ground. Start dropping 2,000lb LGBs or JDAMs, and the weight/balance issue becomes somewhat more important. This can be offset by dropping alternately from forward & aft bays to keep the CG within limits. As an interim solution, the airliner conversion is workable, but there are better ways to create a bomb-truck than fitting a bay to a commercial airliner. The patrol aircraft generally have a requirement for large volumes for the carriage of mission avionics, crew, and sensors and will thus efficiently utilize the volume offered by a commercial airliner. While bombers (or, more specifically, a "bomb truck") do need volume for mission systems, I don't think the requirements are as great as those for maritime patrol.

 

The way I look at the situation, the military should procure those systems that offer the most capability for the missions they will require of the aircraft during wartime. There is some benefit to maintaining multiple systems of varying capability (i.e. the US approach of limited numbers of stealthy aircraft--the B-2--backed up by significant numbers of B-1s and B-52s), but I don't believe procurement of ad hoc conversions of airliners is the way to save money. In a high-intensity conflict, these aircraft will be highly vulnerable and, while they may prove economical for low-intensity conflicts, they will be taking scarce procurement dollars from the more advanced/survivable programs. And for what? We (the US) seem to have the necessary tonnage delivery capacity with the existing systems. The benefits of a high-speed bomber offer a capability that does not currently exist within the inventory: the ability to reduce the aircrew flight hours/fatigue while providing secure basing for the bomber force with the responsiveness achievable by current systems if they were based in-theater. A Mach 3 system can deliver the same payload in the same time from a secure airfield 4x as far from the theater as the subsonic solutions. Airliner conversions offer no real improvement over the B-52 with the possible exceptions of fuel efficiency and improved MTBF (okay, so that is somewhat of an exaggeration). Replacement of the B-52 prematurely (before 2040) incurs the cost of procuring replacements and an entirely new support infrastructure, even before the maintenance costs kick in.

 

Other countries may wish to look at airliner/freighter conversions if they don't have an existing heavy bomber force, in order to save on the engineering costs. By the time you get done redesigning the structure, inventing a new system to dispense the weapons, etc., however, I have a tough time believing that the wings/empennage of an airliner couldn't be married to a new fuselage relatively easily to create a bomber that is weight, space, and cost efficient. Because the US maintains an existing heavy bomber fleet, though, I would want to see a new capability, or a replacement for a retiring system, before I start chucking my tax-dollars away. Hence, I think the B-1R and Mach 3+ bomber projects qualify for further development because of the performance improvements they represent. A CFM56 re-engining of the B-52 qualifies, but replacement of an airframe that has 35 years of life left because someone thinks the concept is neat does not.

 

Douglas

[Chris Werb]

Douglas, how many kinds of USAF ordnance are cleared for release at Mach 3 (or even at in excess of Mach 1.0)? Alternatively, are you advocating that the plane slows down to c. Mach 0.9 as it nears the target?

[Scott Cunningham]

I think the A5 Vigilante used a rear ejecting weapons bay to achieve mach-2 delivery.

[Smitty]

Originally posted by BP:

They still won't be able to haul a Stryker!  

 

Possibly, though even the C-130 CAN haul some Stryker variants over restricted distances, with some preparation.

 

To tell you the truth, I haven't seen any actual figures on the proposed BMACK load. The only thing I saw was carriage of "40 JDAMs in the B configuration". Now I assumed that meant 40 1000lb JDAMs, but that may've been a flawed assumption. It could've meant 40 500lbers or 40 2000lbers.

 

Since 20 tons seems to be the magic number these days (Stryker, FCS, etc.), it would seem to be a reasonable load for a future transport.

[Burncycle360]

Possibly, though even the C-130 CAN haul some Stryker variants over restricted distances, with some preparation.

 

Slung

[JOE BRENNAN]

Somewhat relevant to many of these points, an AWST article this week summarized Lockheed Martin's 4 responses to an AF request for proposals (informal one maybe) about long range strike supplement/replacement for B-2 as:

 

AC-130J "arsenal ship" incl. cruise missiles

FB-22, 120k# gross weight

conventional ICBM giving way to Mach7-10 near space system (not sure why this is given as a single option)

BMACK: stealthy bomber, SOF transport, gunship, transport, tanker

 

My sense is a B-70 redo doesn't appear because it's the incredible cost of clean sheet of paper operational in 10-15yrs (anyone who says let's get our ass in gear and do it in much less and not that much money is not being realistic IMHO) without anything really special to show for it, just some reduction in time to target; similar reason to the hump supersonice airliners have never gotten over.

 

For the US, big airliner based "arsenal ships" have the problem mentioned of not being superior enough to the B-52. I guess the idea of going as low down as C-130 is to avoid this competition. I still really doubt that one. And not really hot on FB-22 either.

 

My inclination would be aim higher, one of the second two options, of course based on realistic firmly grounded expectation of pulling them off, though there would always be risk of a debacle and complete waste of money.

 

Joe

[Burncycle360]

conventional ICBM giving way to Mach7-10 near space system (not sure why this is given as a single option)

Maybe by that they mean an ICBM launched hypersonic cruise missile? The ICBM gets it up to speed required to start the scramjet, and the cruise missile travels at mach 7-10 to the target (maybe bouncing off the atmosphere on the edge of space).

 

If they're going to use ICBMs though, I'm not sure why they don't just use the ICBM with a conventional GPS/INS guided warhead though...

 

Since 20 tons seems to be the magic number these days (Stryker, FCS, etc.), it would seem to be a reasonable load for a future transport.

 

From what I understand, the 20 tons is a "magical number" not because it's ideal, but because the vehicle was designed and built with existing transports in mind, which limited them to around that weight or less. A future transport should carry more and have more space; this gives vehicle designers a little more leeway

 

[Edited by Burncycle360 (06 Dec 2004).]

[JOE BRENNAN]

Originally posted by Burncycle360:

   

Maybe by that they mean an ICBM launched hypersonic cruise missile? The ICBM gets it up to speed required to start the scramjet, and the cruise missile travels at mach 7-10 to the target (maybe bouncing off the atmosphere on the edge of space).

 

If they're going to use ICBMs though, I'm not sure why they don't just use the ICBM with a conventional GPS/INS guided warhead though...

 

 

It meant the latter first, GPS guided ICBM, which has been mentioned alot, potentially as Minuteman upgrade but this would be something new; then the near space system. But it was vague as to how that related to an ICBM, perhaps common booster as you said at some stage of its evolution, but it also mentioned runways (taking off not only landing it was implied) for such a craft.

 

I love AWST overall but find many of their articles confusingly written actually, wonder if anyone else who reads it agrees. I guess it's less critical when discussing pie in sky proposals that will change a million times before they ever become reality if they ever do.

 

Joe

 

[Edited by JOE BRENNAN (06 Dec 2004).]

[Ivanhoe]

Originally posted by Burncycle360:

Slung  

 

Give me a break. The obvious way for a Herc to carry Strykers is on the roof, like the Shuttle Transporter. Round fuselage means the tires neatly straddle and stabilize. With a few tiedown points judiciously located, they'd be kept safe and sound, away from any windshield-cracking FOD during takeoffs and landings.

[Ol Paint]

Originally posted by Chris Werb:

Douglas, how many kinds of USAF ordnance are cleared for release at Mach 3 (or even at in excess of Mach 1.0)?  Alternatively, are you advocating that the plane slows down to c. Mach 0.9 as it nears the target?  

 

Actually, Chris, that is exactly what I am suggesting for the scenario as I see it. High speed is a transit capability that the aircraft uses to get to the theater as quickly as possible. The aircraft would then decelerate to subsonic speed to loiter over the target areas. Which points to another advantage I didn't consider before. The high-speed bomber could quickly reposition within the theater, if necessary.

 

I have no idea what ordnance is cleared for delivery at >1.0M. Perhaps calvinb1nav could enlighten us, if he is lurking? I would assume that the FB-111 and B-1 had supersonic release capabilities, at some point. As Scott noted, the A-5 certainly did (although the stores tended to "draft" behind the aircraft), and the B-58 did, as well.

 

Douglas

[Chris Werb]

If you're only transiting at high speed, that makes a lot more sense. I'd guess that the only air to ground ordnance cleared for supersonic release would be SRAM, some B-61s and all(?) B-83s plus (possibly) HARM, Maverick and clean LDGPs.

[Chris Werb]

This page implies SSB will be capable of supersonic release from inside an F/A-22:

http://www.arnold.af.mil/aedc/highmach/sto...ories/F111.html

 

Another mentions JDAM release up to M 1.3:

[Jeff]

Originally posted by Ol Paint:

I have no idea what ordnance is cleared for delivery at >1.0M.  Perhaps calvinb1nav could enlighten us, if he is lurking?  I would assume that the FB-111 and B-1 had supersonic release capabilities, at some point.  

 

I think the B1B does most of it's work subsonic though it is capable of flying supersonic at sealevel. Lately it's just done the high altitude loiter I believe.

[Ol Paint]

Originally posted by Jeff:

I think the B1B does most of it's work subsonic though it is capable of flying supersonic at sealevel. Lately it's just done the high altitude loiter I believe.

 

True, but I was thinking that the aircraft was probably qualified earlier in its career to drop while supersonic. I was also guessing that the B-1A program may have investigated this aspect of delivery, although modern muntions may not have been constructed with this method in mind (I am thinking specifically of the mechanicals for the guided munitions--esp. LGBs).

 

Douglas