Stitch wrote:

Frankly I would think a 747-8 freighter might be the better option since they can just front-load all the equipment bays and such in through the nose door rather than trying to shoe-horn it all in through the passenger doors.

Not necessarily.

If you keep the electronic racks in the lower lobe, it would help.

From that video walk thru of the existing E-4, I don't see anything that wouldn't be able to get through the main door. I mean if they an get a double wide equipment rack though the 737 entry door, they should be able to get them through the 747 door.

More importantly though, the -8I seat tracks are more efficient ways to attach all the stuff you you need to attach to the floor. The freighter floor may be stronger, you either need to remove the cargo handling system which forces you to set up new mounting systems, or design adapter plates to be placed on top of the cargo handling system.

bt

The other thing to notice is the crew entry through the lower lobe cargo door on the existing aircraft. So during the mod process, they can get equipment through the lower lobe, then lift it up to the main deck by making the stairs opening large enough to handle large main deck monuments.

bt

bikerthai wrote:

More importantly though, the -8I seat tracks are more efficient ways to attach all the stuff you you need to attach to the floor. The freighter floor may be stronger, you either need to remove the cargo handling system which forces you to set up new mounting systems, or design adapter plates to be placed on top of the cargo handling system.

It would be interesting if the designed everything to be palletized so that when new versions come out, they could just swap it out. The C-17s have those fancy "General Suites" on pallets they can roll on and off so you could do that for things like the conference rooms and NCA suites.

Paletizarion can be achieved with the passenger seat tracks mount as well. The real trick with roll on roll off would be predicting the wiring/power/cooling requirements for future needs and standardize a common interface for each pallet position.

MC2A was looking in to that before it was canceled. Not sure how the technology has matured since then.

One thing that would help with paletization will be going wireless for the data link, so you just have to worry about power cooling and some standard fiber data bus.

bt

ssteve wrote:

ZaphodHarkonnen wrote:

ssteve wrote:

Yeah... you think this means -8 for sure? So, which 8i's, assuming the 8F's are gainfully employed?

Likely whatever they can get their hands on. 8F or 8i won't make too much difference as the things will be gutted anyways.

What is the significant difference between the E-6B and E-4B that necessitates the USAF requiring the 747? Do the SECDEF and JCS really need a 747 for command & control and secure communication? Are the mission profiles and equipment power needs between the TACAMO and NAOC really that different?

On a meta level, the E-4B prosecutes a nuclear exchange and the E-6B carries out the engagement.

So the Battle Staff on the E-4B decide which OPLAN to employ and then the E-6B issues the launch orders to the bombers, missile silos and SSBNs to execute.

I expect both missions could be integrated into a single frame, if desired.

Wait, WIKI says the E-6B is a Navy plane. So would they be limited to coordinate with the Navy assets only?

There are 16 E-6B and only 4 E-4B.

Will they need to replace all four E-4B one for one?

bt

bikerthai wrote:

Wait, WIKI says the E-6B is a Navy plane. So would they be limited to coordinate with the Navy assets only?

I believe the E-6A could only communicate with the SSBNs.

When the fleet was updated to the E-6B standard, they could also communicate with USAF bombers and the ICBM silos so they can now control the entire Triad, if necessary, and the USAF retired the EC-135C "Looking Glass" fleet as it was no longer necessary.

Stitch wrote:

bikerthai wrote:

Wait, WIKI says the E-6B is a Navy plane. So would they be limited to coordinate with the Navy assets only?

I believe the E-6A could only communicate with the SSBNs.

When the fleet was updated to the E-6B standard, they could also communicate with USAF bombers and the ICBM silos so they can now control the entire Triad, if necessary, and the USAF retired the EC-135C "Looking Glass" fleet as it was no longer necessary.

Stich, good reply as always. And this is why I asked the question. I get that we need redundancy in the event of an 'incident' but do we need two services manning two different platforms with such overlapping mission profiles? The crew of the E-4 should not be any larger than the E-6, but it the SECDEF and JCS and their staff that determines the larger size? Now let's also bring into the fact USSTRATCOM is responsible for strategic deterrence, global strike, and operating the Defense Department's Global Information Grid, which operates out of Offutt, why is there also the need for TACAMO as a relay node out of Tinker? It just seems like this could all be one platform unless the E-4B cannot handle the amount of signal relays and antenna in addition to its main mission equipment.

As I understand it, the E-4B platform was procured because the VC-137C models serving as Air Force One (SAM 26000 and SAM 27000) lacked the communications suite, the floorspace and the endurance to serve the President effectively in the event of a major nuclear exchange between the US and the Soviets.

The arrival of the VC-25A platform alleviated much of these deficiencies present in the VC-137C so the E-4B became available to the Secretary of Defense for their use when on official travel in addition to its role as a command post for the President and USSTRATCOM.

I expect the VC-25B will be even more capable as a command post ( 9/11 exposed some weaknesses in the VC-25A for this role which were addressed via upgrades ) so I was somewhat skeptical that the USAF would go for a one-to-one replacement.

The TACAMO role is rather specialized in that the airframe has to be able to communicate across most of radio band of the electromagnetic spectrum (SHF down to VLF). My guess is that the DoD prefers a dedicated TACAMO frame to ensure nuclear deterrence even if the role could be rolled into an E-4B replacement.

I expect this is also why the USAF wants a large four-engine frame to replace the E-4B for redundancy and reliability during a major conflict / nuclear exchange (and that reliability and redundancy's contribution to deterrence).

Stitch wrote:

As I understand it, the E-4B platform was procured because the VC-137C models serving as Air Force One (SAM 26000 and SAM 27000) lacked the communications suite, the floorspace and the endurance to serve the President effectively in the event of a major nuclear exchange between the US and the Soviets.

The arrival of the VC-25A platform alleviated much of these deficiencies present in the VC-137C so the E-4B became available to the Secretary of Defense for their use when on official travel in addition to its role as a command post for the President and USSTRATCOM.

I expect the VC-25B will be even more capable as a command post ( 9/11 exposed some weaknesses in the VC-25A for this role which were addressed via upgrades ) so I was somewhat skeptical that the USAF would go for a one-to-one replacement.

The TACAMO role is rather specialized in that the airframe has to be able to communicate across most of radio band of the electromagnetic spectrum (SHF down to VLF). My guess is that the DoD prefers a dedicated TACAMO frame to ensure nuclear deterrence even if the role could be rolled into an E-4B replacement.

I expect this is also why the USAF wants a large four-engine frame to replace the E-4B for redundancy and reliability during a major conflict / nuclear exchange (and that reliability and redundancy's contribution to deterrence).

Thanks, Stitch! Always good to learn something new.

Article linked below, confirms that the USAF does not intend to incorporate a replacement of the C-32 & C-40s with the E-4s (which supports the previous articles of their intentions to buy a four holer).

https://www.airforcetimes.com/news/your ... day-plane/

They should procure Ex pax 747-400’s that are late build low time/cycle frames. There out there how long they remain nobody knows. The E-4 will have to be replaced at some point.

DL757NYC wrote:

They should procure Ex pax 747-400’s that are late build low time/cycle frames. There out there how long they remain nobody knows. The E-4 will have to be replaced at some point.

The cost saving from using a -400 will be negated by the additional engineering cost to "militarize the the model".

Much of the militarization designed for the -8 under the VC-25B and can be re-used.

Note that airframe design is only part of the cost. Much the the electronic rack design for VC-25B can be re-used for any 747-8 based E-4.

The other aspect of design is the 747-8 is a digigtal airplane, so engineering for the mod is easier.

The -400 may not have complete digital definition. And I'm pretty sure what they have would be in the old version of CATA (V-4 vs V5).

bt

AFAIK, the first 744 to be built according digital drawings is L/N 1145 (master drawing R6601), a 747-409, C/N 29030, B-18206 for China Airlines, delivered at Feb 25th 1998.
Also all tolerances during Final Assembly were reduced and the first 744 aircaft built according the new assembly program (FAIT) was L/N 1236, a 747-446, JA8919 for JAL, delivered at Dec 16th 1999.
But as noted above, all 744 digital drawings were made with older versions of CATIA.

Less complicated and far less expensive would be an E-4B successor, based at the fully digital designed 747-8 series, with a lot of military mods already certified at the VC-25B aircraft.
Also the GEnx-2B engines at the VC-25B's are already "hardened" and a modified accessory gearbox is installed to drive one extra IDG, also required at the E-4B successor.

bikerthai wrote:

DL757NYC wrote:

They should procure Ex pax 747-400’s that are late build low time/cycle frames. There out there how long they remain nobody knows. The E-4 will have to be replaced at some point.

The cost saving from using a -400 will be negated by the additional engineering cost to "militarize the the model".

Much of the militarization designed for the -8 under the VC-25B and can be re-used.

Note that airframe design is only part of the cost. Much the the electronic rack design for VC-25B can be re-used for any 747-8 based E-4.

The other aspect of design is the 747-8 is a digigtal airplane, so engineering for the mod is easier.

The -400 may not have complete digital definition. And I'm pretty sure what they have would be in the old version of CATA (V-4 vs V5).

bt

For some reason, the whole "let's take an airplane from previous era, and thoroughly modernize it, thus saving money" reminds of a beautiful thread, on this very forum, about Nimrod re-winging fiasco.
About a massive effort to fully create a digital master drawing set for a single airframe, only to realize that other airframes are not really identical to it...
About a cost overrun so massive, as to eventually abandoning the entire program...

Yes. probably these days. compatibility would win both on cost on and on performance.
Just buying feedstock airframes cheaply would not make the program cheaper.
Compatible airframes, as fully known quantities, would be way better.

and 747-8 is inherently compatible.

Another nice article somewhat implicates the USAF in dragging their feet on this program.

https://www.politico.com/news/2022/05/2 ... e-00034686

It also have to do with modern day manufacturing process and schedule.

In the old day, you take each frames before mod, and measure our all the new interface points to make sure the new stuff fits, specially wiring, pneumatics and hydraulics. Then you basically custom build each runs as the mod progress. It takes longer to do this.

Now, if you have a digital model, you prefab all the bundles and tubes and install it on the airframes along with the required brackets, knowing the lengths are good. Of course there would always be snafus. But those would be fewer and does not discourage pre-fabbing the kits.

bt

Phosphorus wrote:

bikerthai wrote:

DL757NYC wrote:

They should procure Ex pax 747-400’s that are late build low time/cycle frames. There out there how long they remain nobody knows. The E-4 will have to be replaced at some point.

The cost saving from using a -400 will be negated by the additional engineering cost to "militarize the the model".

Much of the militarization designed for the -8 under the VC-25B and can be re-used.

Note that airframe design is only part of the cost. Much the the electronic rack design for VC-25B can be re-used for any 747-8 based E-4.

The other aspect of design is the 747-8 is a digigtal airplane, so engineering for the mod is easier.

The -400 may not have complete digital definition. And I'm pretty sure what they have would be in the old version of CATA (V-4 vs V5).

bt

For some reason, the whole "let's take an airplane from previous era, and thoroughly modernize it, thus saving money" reminds of a beautiful thread, on this very forum, about Nimrod re-winging fiasco.
About a massive effort to fully create a digital master drawing set for a single airframe, only to realize that other airframes are not really identical to it...
About a cost overrun so massive, as to eventually abandoning the entire program...

Yes. probably these days. compatibility would win both on cost on and on performance.
Just buying feedstock airframes cheaply would not make the program cheaper.
Compatible airframes, as fully known quantities, would be way better.

and 747-8 is inherently compatible.

When BAe became BAE Systems, they got rid of a lot of those pesky staff, with long experience, likely on better pay and pensions, who would have warned of this. Some of them likely built the original frames.
Plus the Treasury, in 1996 BAe offered both the rebuild or all new, the Treasury were loath enough to fund a new ASW aircraft, hadn't the MoD realised the Cold War was over? So they split the difference, 're-build' must be cheaper than all new, right?

I was in BA Concorde tech at the time, they had differences between each frame, beyond G-BOAF the last ever built, being a tonne lighter than G-BOAC, though when the Air Intake Control Units needed either replacing or rebuilding/replicate the originals, (quickly settling on the latter as for all the advantages of 25 year newer computer technology, neither operator could spare an aircraft for the long process of testing to get regulatory approval for an all new control system).
The originals had been built by HSGW, the guided weapon division of Hawker, so now BAE had to ask people back from retirement to fix problems they couldn't, same happened with the replacement rudders too, they messed up on the sealant so the new ones lasted for a fraction of the time the originals had.

Gone massively off topic there, sorry!
I don't think though what I outlined above will remotely happen with the E-4B replacement, for one our 'airline operation within an airline' was hardly compatible with the sheer resources of the DoD and Boeing. The latter have blotted their copybook a lot in recent times, such a high profile and high scrutiny program like this might even restore some better practice all around?

I am still pissed BAE screwed up the MRA.4A though, should have brought 'em all new.

GDB wrote:

The latter have blotted their copybook a lot in recent times, such a high profile and high scrutiny program like this might even restore some better practice all around?

Best practice do get incorporated in to document processes. Taking time to read the processes an understand it fully is another matter. That is if the best practice is still applicable with the new processes.

Alas, for US manufacturing companies, many of the experienced personel took the COVID epidemic as a cue to retire and enjoy life. Boeing would be no exception. I predict they will have labor related production ramp up issues in the next few years.

The E-4 being small enough project might not be as big a problem.

bt

Reading the last replies about this subject, it would be the best choice for the USAF to use digital designed 747-8I aircraft, built according exactly the same specs to obtain the same starting point for each to be converted airframe.
The prime candidates for a E-4B successor would be the last built Korean 747-8I's or the last built DLH 747-8I's
Using Air China's 747-8I's would be political difficult.

Ideal would be :
Korean :
L/N 1539
L/N 1537
L/N 1531
L/N 1529

Remark : L/N 1538 has already been modified for use by the Government of South Korea

or Lufthansa :
L/N 1514
L/N 1513
L/N 1512
L/N 1511

Remark : Lufthansa 747-8I's have a higher flight hour/cycle count than the Korean 747-8I aircraft !

747classic wrote:

Reading the last replies about this subject, it would be the best choice for the USAF to use digital designed 747-8I aircraft, built according exactly the same specs to obtain the same starting point for each to be converted airframe.
The prime candidates for a E-4B successor would be the last built Korean 747-8I's or the last built DLH 747-8I's
Using Air China's 747-8I's would be political difficult.

Ideal would be :
Korean :
L/N 1539
L/N 1537
L/N 1531
L/N 1529

Remark : L/N 1538 has already been modified for use by the Government of South Korea

or Lufthansa :
L/N 1514
L/N 1513
L/N 1512
L/N 1511

Remark : Lufthansa 747-8I's have a higher flight hour/cycle count than the Korean 747-8I aircraft !

and Koreans retiring them at the end of the decade but could be persuaded to do it earlier with some cash sooooo....

bikerthai wrote:

GDB wrote:

The latter have blotted their copybook a lot in recent times, such a high profile and high scrutiny program like this might even restore some better practice all around?

Best practice do get incorporated in to document processes. Taking time to read the processes an understand it fully is another matter. That is if the best practice is still applicable with the new processes.

Alas, for US manufacturing companies, many of the experienced personel took the COVID epidemic as a cue to retire and enjoy life. Boeing would be no exception. I predict they will have labor related production ramp up issues in the next few years.

The E-4 being small enough project might not be as big a problem.

bt

I don’t see using ex Air China planes as impossibly unpalatable. The Chinese government use Boeing planes as state aircraft. So clearly they feel comfortable enough even if they’re US assembled.

How ironic would that be? New VC-25's being developed from repurposed 747-8i's meant for a defunct Russian airline and possible E-4 replacement using previously owned by a Chinese airline.

tmu101 wrote:

How ironic would that be? New VC-25's being developed from repurposed 747-8i's meant for a defunct Russian airline and possible E-4 replacement using previously owned by a Chinese airline.

That is dang funny. LOL.

texl1649 wrote:

tmu101 wrote:

How ironic would that be? New VC-25's being developed from repurposed 747-8i's meant for a defunct Russian airline and possible E-4 replacement using previously owned by a Chinese airline.

That is dang funny. LOL.

Be even funnier if they embed some electronic devices in the a/c before they are obtained...may never be found....

par13del wrote:

even funnier if they embed some electronic devices in the a/c before they are obtained...may never be found....

Funny but not practical. Any device worth its salt will need a power supply and a transmitting antenna. Those can be found more readily.

The final frame will have to go through a thorough EMI shielding evaluation test once the mod is complete to make sure signals don't leak in or out.

If they can sneak something in to the existing commerical electronics and wiring, it may be harder to detect. But if you were to harden the frame you would want to strip out the commercial flight control wiring as well and replace them with shield bundles as well.

Sometimes, for a mod like this where you are puting in an order of magnitude more wiring than existing bundles, it is just easier to strip out everything and put in new wiring, even for existing systems.

bt

bikerthai wrote:

par13del wrote:

even funnier if they embed some electronic devices in the a/c before they are obtained...may never be found....

Funny but not practical. Any device worth its salt will need a power supply and a transmitting antenna. Those can be found more readily.

The final frame will have to go through a thorough EMI shielding evaluation test once the mod is complete to make sure signals don't leak in or out.

If they can sneak something in to the existing commerical electronics and wiring, it may be harder to detect. But if you were to harden the frame you would want to strip out the commercial flight control wiring as well and replace them with shield bundles as well.

Sometimes, for a mod like this where you are puting in an order of magnitude more wiring than existing bundles, it is just easier to strip out everything and put in new wiring, even for existing systems.

bt

If that's level of disassembly expected, than not only Air China's 747's would probably qualify.
I gather A380's (available dime a dozen) would qualify too.
Whether USAF would accept an additional platform (Europe-built, at that), is a different question altogether.

ZaphodHarkonnen wrote:

I don’t see using ex Air China planes as impossibly unpalatable. The Chinese government use Boeing planes as state aircraft. So clearly they feel comfortable enough even if they’re US assembled.

Comfortable? I'm sure the Chinese will inspect the aircraft from top to bottom following incident discussed in this article:

https://www.chicagotribune.com/news/ct- ... story.html

zanl188 wrote:

ZaphodHarkonnen wrote:

I don’t see using ex Air China planes as impossibly unpalatable. The Chinese government use Boeing planes as state aircraft. So clearly they feel comfortable enough even if they’re US assembled.

Comfortable? I'm sure the Chinese will inspect the aircraft from top to bottom following incident discussed in this article:

https://www.chicagotribune.com/news/ct- ... story.html

Couple of things:
1. the aircraft was custom ordered as a VIP aircraft from the start;
2. the aircraft received a custom VIP interior in the US

Since then, the Chinese have mostly used Air China aircraft pulled from the active Air China fleet, and reconfigured with a VIP interior for the mission. The aircraft were never ordered as VIP aircraft from the beginning.

ThePointblank wrote:

Couple of things:
1. the aircraft was custom ordered as a VIP aircraft from the start;
2. the aircraft received a custom VIP interior in the US

Is it true that the bugs were planted by Chinese faction and not any foreign government? Or was that an urban myth?

As for the mod, I think they would need to strip out all the insulation blankets anyway as the mod work would damage them if left in place.

After the blankets are out, they would do a thorough inspection for any structural anomaly.

It would not be effective planting the bugs before the mod.

bt

bikerthai wrote:

ThePointblank wrote:

Couple of things:
1. the aircraft was custom ordered as a VIP aircraft from the start;
2. the aircraft received a custom VIP interior in the US

Is it true that the bugs were planted by Chinese faction and not any foreign government? Or was that an urban myth?

As for the mod, I think they would need to strip out all the insulation blankets anyway as the mod work would damage them if left in place.

After the blankets are out, they would do a thorough inspection for any structural anomaly.

It would not be effective planting the bugs before the mod.

bt

I would suspect that any major mod of an aircraft would include a crack inspection for any cracks over 5 mm long. Hard to build a bug including power supply for 10 years and an antenna as a fake rivet to avoid being found in said inspection.

Phosphorus wrote:

bikerthai wrote:

par13del wrote:

even funnier if they embed some electronic devices in the a/c before they are obtained...may never be found....

Funny but not practical. Any device worth its salt will need a power supply and a transmitting antenna. Those can be found more readily.

The final frame will have to go through a thorough EMI shielding evaluation test once the mod is complete to make sure signals don't leak in or out.

If they can sneak something in to the existing commerical electronics and wiring, it may be harder to detect. But if you were to harden the frame you would want to strip out the commercial flight control wiring as well and replace them with shield bundles as well.

Sometimes, for a mod like this where you are puting in an order of magnitude more wiring than existing bundles, it is just easier to strip out everything and put in new wiring, even for existing systems.

bt

If that's level of disassembly expected, than not only Air China's 747's would probably qualify.
I gather A380's (available dime a dozen) would qualify too.
Whether USAF would accept an additional platform (Europe-built, at that), is a different question altogether.

But would the USAF want a platform that is very limited in the number of airports at which it could land? Lots of airports that can handle a 747 can't handle an A380.

flyingclrs727 wrote:

Phosphorus wrote:

bikerthai wrote:

Funny but not practical. Any device worth its salt will need a power supply and a transmitting antenna. Those can be found more readily.

The final frame will have to go through a thorough EMI shielding evaluation test once the mod is complete to make sure signals don't leak in or out.

If they can sneak something in to the existing commerical electronics and wiring, it may be harder to detect. But if you were to harden the frame you would want to strip out the commercial flight control wiring as well and replace them with shield bundles as well.

Sometimes, for a mod like this where you are puting in an order of magnitude more wiring than existing bundles, it is just easier to strip out everything and put in new wiring, even for existing systems.

bt

If that's level of disassembly expected, than not only Air China's 747's would probably qualify.
I gather A380's (available dime a dozen) would qualify too.
Whether USAF would accept an additional platform (Europe-built, at that), is a different question altogether.

But would the USAF want a platform that is very limited in the number of airports at which it could land? Lots of airports that can handle a 747 can't handle an A380.

Yes, there apparently is a million reasons why not A380. when A380 was getting ready to takeoff, years ago, I remember people at US airport authorities (major international gateways, mind you) speaking, on record, "we need to get serious on waivers"

Still, it's a 4-engine plane, available on second-hand market in quantity, that has size to accommodate the toys.

flyingclrs727 wrote:

But would the USAF want a platform that is very limited in the number of airports at which it could land? Lots of airports that can handle a 747 can't handle an A380.

In terms of general civilian movements, the 747-8 is considered the same category as the A380.

The E-4Bs, being military platforms, certainly have their own special ground handling considerations well beyond what a civilian 747-200 would and that no doubt means the airframe would not operate into any 747-200-capable field. The same would apply to an "E-4C", be it a 747-8, A380 or something else.

Realistically, the "E-4C" is going to be a 747-8 because the USAF can directly leverage their experience with the VC-25B program.

Stitch wrote:

flyingclrs727 wrote:

But would the USAF want a platform that is very limited in the number of airports at which it could land? Lots of airports that can handle a 747 can't handle an A380.

In terms of general civilian movements, the 747-8 is considered the same category as the A380.

The E-4Bs, being military platforms, certainly have their own special ground handling considerations well beyond what a civilian 747-200 would and that no doubt means the airframe would not operate into any 747-200-capable field. The same would apply to an "E-4C", be it a 747-8, A380 or something else.

Realistically, the "E-4C" is going to be a 747-8 because the USAF can directly leverage their experience with the VC-25B program.

But in a wartime situation, they may want to land at the first suitable airport not necessarily one that would be suitable of operations.

flyingclrs727 wrote:

But in a wartime situation, they may want to land at the first suitable airport not necessarily one that would be suitable of operations.

Then they should really be using the 767-2C (the base for the KC-46A) since a 767 can operate out of far more fields than a 747-8, much less an A380.

I would expect the "E-4C" will have the mid-air refueling that has been omitted from the VC-25B so it should have the multi-day airborne endurance of the E-4B. So should a strategic nuclear exchange occur, that would give it the flexibility to fly to a suitable surviving airfield once the first waves of warheads have impacted.

flyingclrs727 wrote:

Stitch wrote:

flyingclrs727 wrote:

But would the USAF want a platform that is very limited in the number of airports at which it could land? Lots of airports that can handle a 747 can't handle an A380.

In terms of general civilian movements, the 747-8 is considered the same category as the A380.

The E-4Bs, being military platforms, certainly have their own special ground handling considerations well beyond what a civilian 747-200 would and that no doubt means the airframe would not operate into any 747-200-capable field. The same would apply to an "E-4C", be it a 747-8, A380 or something else.

Realistically, the "E-4C" is going to be a 747-8 because the USAF can directly leverage their experience with the VC-25B program.

But in a wartime situation, they may want to land at the first suitable airport not necessarily one that would be suitable of operations.

The whole size thing is about fitting nicely into gates and taxiing around busy airports.

Just how many times has an E-4 used a gate and jetbridge?

There will be plenty of runways around the world and especially the US that an B747-8 or even and A380 could land at even if the airfield isn't designed to routinely handle their operation. And if they have to get to the ground in that sort of a hurry in a wartime scenario then they've already got bigger problems.

If the A380 was the only option capable of this out there then it just might be considered. But there are 747-8s out there that can be bought and modified. And as mentioned several times, the work on the VC-25B will mean the hardest bits are basically already done.

Now that the B767-2C is basically out of the running I'd be stunned if it ended up being anything but a 747-8. The real question now is would it be the F or i model.

ZaphodHarkonnen wrote:

The real question now is would it be the F or i model.

If you want to maximize floor space, then it would ve the I model. From a mod perspective, the I is also easier to design for interiors and mission accomodations as it is more efficient attaching stuff to the seat tracks than the cargo handling system.

bt

If they had ever built the proposed A380-700 shrink, that would have made a good E-4 replacement. Given all that wing, and with the right engines (Trent XWB-84's), I'll bet it could have cruised at FL470 all day and have a range of 10,000+ nmi.

744SPX wrote:

If they had ever built the proposed A380-700 shrink, that would have made a good E-4 replacement. Given all that wing, and with the right engines (Trent XWB-84's), I'll bet it could have cruised at FL470 all day and have a range of 10,000+ nmi.

Well couldn't some low cycle A380's be remanufactured as such a shrink if it were worthwhile?

Don't think USAF will go non-Boeing. Just my guess, Guessing four 748-i's from the PAX operators. Or maybe three plus the Saudi government 748 BBJ ntu bought back recently by Boeing.

Where I am lost on the size issue, they are/were looking at replacing 707 E3's with Learjets, totally bypass the 767 which is being built for them....now the E-4 must be replaced not just in like size but in an engine configuration that is no longer being manufactured in and for the civilian market.

par13del wrote:

Where I am lost on the size issue, they are/were looking at replacing 707 E3's with Learjets, totally bypass the 767 which is being built for them....now the E-4 must be replaced not just in like size but in an engine configuration that is no longer being manufactured in and for the civilian market.

I can honestly understand why the USAF wants a "like for like" replacement for the E-4B in terms of general size and engine configuration. The stated purpose of this platform is to stay airborne for days in an environment where major infrastructure centers have been subjected to direct nuclear attack.

You need a plane with lots of engines so it can stay aloft if one or even two of them fail and where you have enough space to carry plenty of provisions and staffers to prosecute a multi-day strategic nuclear engagement against (likely) multiple antagonists.

par13del wrote:

Where I am lost on the size issue, they are/were looking at replacing 707 E3's with Learjets, totally bypass the 767 which is being built for them....now the E-4 must be replaced not just in like size but in an engine configuration that is no longer being manufactured in and for the civilian market.

Wild guess? Different capability parameters.

E-4 has a paramount survivability mandate. Fate of any one (of four) is decisive to life or death of humankind, sorry for big words.

E-3 is an expensive, but replaceable asset. Making it cheaper while as capable is a normal numbers game. If you can miniaturize your requirements enough, to squeeze them into a business jet -- great for you.

Probably flying Pentagon cannot be made small and capable at once, and survivable enough, unless you wander into 747 territory.

Phosphorus wrote:

E-3 is an expensive, but replaceable asset. Making it cheaper while as capable is a normal numbers game.

For rhe E-3 replacement, rhe numbers game is in the number of phased array elements you can put in to the air. Putting fewer elements on smaller jets improve survivability but then you need more of the smaller jets.

bt

Why not C17’s already in USAF inventory?

Stitch wrote:

par13del wrote:

Where I am lost on the size issue, they are/were looking at replacing 707 E3's with Learjets, totally bypass the 767 which is being built for them....now the E-4 must be replaced not just in like size but in an engine configuration that is no longer being manufactured in and for the civilian market.

I can honestly understand why the USAF wants a "like for like" replacement for the E-4B in terms of general size and engine configuration. The stated purpose of this platform is to stay airborne for days in an environment where major infrastructure centers have been subjected to direct nuclear attack.

You need a plane with lots of engines so it can stay aloft if one or even two of them fail and where you have enough space to carry plenty of provisions and staffers to prosecute a multi-day strategic nuclear engagement against (likely) multiple antagonists.

In which case they may as well start the project to have a clean sheet 4 engine a/c, nuclear weapons are not going away so the role of the E-4B will continue for many years to come - pending all out war - so how long will this stop gap product hold up before the maintenance gets unbearable? My assumption is that the E-4B get as much as or more flying time than the VC birds.

par13del wrote:

In which case they may as well start the project to have a clean sheet 4 engine a/c, nuclear weapons are not going away so the role of the E-4B will continue for many years to come - pending all out war - so how long will this stop gap product hold up before the maintenance gets unbearable? My assumption is that the E-4B get as much as or more flying time than the VC birds.

I have read that when travelling with the US, SecDef now flies on C-32s to help cut down on hours. Only when they travel out of North America do they take an E-4B.

Creating a true-clean sheet frame would take decades and costs tens of billions with how military programs are procured. That is why they will end up using passenger 747-8 airframes because they already know how to harden one of them and equip them with full communications suites thanks to the VC-25B program so they can put it into service far faster and far cheaper than a clean-sheet.