L3 Harris is apparently pushing the USAF to add on the Embraer KC390 as a tactical tanker, even with a boom, in hopes to avoid another "tanker war". I wonder if this could lead to the KC390 eventually replacing the C130.

But ultimately it kinda smells of L3 trying to get a nice big piece of government spending pie. Especially considering the rumors of the Pentagon wanting a stealth tanker for peer/near-peer conflicts.

https://breakingdefense.com/2022/09/tac ... nker-wars/

What would be the point of a smaller tanker ?

My thoughts also. Along with the stealth rumors, there have been rumors of a larger tanker based on the 777, but that may just be an a.net thing.

If there is a small tanker, I'd still expect it to be stealth, maybe based on the B21 frame. The only assets that'd be heading in to contested airspace that would need a tanker are the fast movers and stealth bombers so a top off from a platform that's still long range would be adequate. Anything else in uncontested airspace, the fully amortized KC135 would do.

The tactical tanker is supposed to be able to refuel aircraft operating from forward improvised rough & unimproved airfields. The concept is valid but in practice this tanker would be range limited and very vulnerable. So it would be more of a niche application. The USAF might bite on a few of them, but they aren't going to resolve KC-Y.

TWA772LR wrote:

If there is a small tanker, I'd still expect it to be stealth, maybe based on the B21 frame. The only assets that'd be heading in to contested airspace that would need a tanker are the fast movers and stealth bombers so a top off from a platform that's still long range would be adequate.

I agree.

I think L3 has completely misinterpreted the leaked information from the USAF. Tactical tanker doesn't mean just smaller but also closer to the front line. This means it MUST be unmanned and it MUST have a lower radar cross section than an airliner or cargo aircraft. I'm not talking full F-35 levels of stealth.

As is must fit a refueling boom it has to be much bigger than the MQ-25 drone tanker. The B-21 frame appears perfect in size. The B-2 has around 80% of the fuel capacity of the KC-46 and the B-21 is noticeably smaller than the B-2. So the B-21 might have around half the fuel capacity of the KC-46 which sounds perfect for me. The B-21 apparently can be optionally manned and the central bomb bay would allow for a boom to be mounted. I think the tanker and B-21 could have 90+% commonality and built on the same production line up to a certain point.

During production the B-21 gets stealth "skins" and stealth coatings the tanker version gets plain carbon skins with durable commercial paint. No cockpit is installed in the tanker version but the systems to allow for the autonomous flight are kept. I don't think the boom even needs to fully retract into the bomb bay. The bomb bay gives nice space to mount the boom systems. I think a huge portion of the B-21 production cost will be the sensors and stealth surfaces. As a result I could see the tanker version being half the cost of the stealth bomber version.

There remains no observable facts supporting the assertion the USAF intends to fund development of a stealthy tactical tanker capability, let alone that the B-21 could be modified to fit such a role.

Anything approaching an off the shelf solution with multi role capabilities and simple acquisition should be considered, whether it come from Lockheed/Airbus, Embraer, Boeing or someone else as I don’t think ongoing reliance on exclusively the KC-46 to replace the huge KC-135 fleet makes any sense. The decades of futility to get the Pegasus into service finally should militate the acquisition machinery to go for ‘simple’ vs. ‘new stealthy concept.’

The future of USAF tanking is a steady transition from the KC-135 to the KC-46, followed by whatever KC-Z turns out to be. USAF has expressed interest in a BWB aircraft for KC-Z. But that is very preliminary.

A tanker version of the C-130 (with boom) would obviously have more commonality with what the USAF already flies. Does the KC-390 have much of an advantage? (Yes, it does somewhat better in payload-range, but it's not a huge increase.)

texl1649 wrote:

There remains no observable facts supporting the assertion the USAF intends to fund development of a stealthy tactical tanker capability, let alone that the B-21 could be modified to fit such a role.

Anything approaching an off the shelf solution with multi role capabilities and simple acquisition should be considered, whether it come from Lockheed/Airbus, Embraer, Boeing or someone else as I don’t think ongoing reliance on exclusively the KC-46 to replace the huge KC-135 fleet makes any sense. The decades of futility to get the Pegasus into service finally should militate the acquisition machinery to go for ‘simple’ vs. ‘new stealthy concept.’

I would go further, in that for USAF tankers the need to go past KC-Y where 2/3 of the KC-135 will have been replaced is relatively low. Besides, a number of large factors will need to play out for a decade or more for the planners to have a clear picture:

-B-52 Re-engine - with 20+% more range, far less need to refuel. Also only 76 in total.
-B-1 and B-2 retirements
-B-21 actual experience
-The KC-46 has improved characteristics compared to the KC-135, allowing it to operate closer to the front line - but how much more.
-How the MQ-25 drone performs and the overall drone tanker operations
-Refueling of drones, the best size for this and operational such as "Mother Ship" concepts Would smaller MQ-25 type drones shuttle from the mother ship or ?
-Total fleet size and percent of fleet that are drones.

There are a lot of moving targets here, it might be a decade before the Air Force realizes the specific specs for this new tanker. Until then it is more of wish list placeholders.

RJMAZ wrote:

As is must fit a refueling boom it has to be much bigger than the MQ-25 drone tanker. The B-21 frame appears perfect in size. The B-2 has around 80% of the fuel capacity of the KC-46 and the B-21 is noticeably smaller than the B-2. So the B-21 might have around half the fuel capacity of the KC-46 which sounds perfect for me. The B-21 apparently can be optionally manned and the central bomb bay would allow for a boom to be mounted. I think the tanker and B-21 could have 90+% commonality and built on the same production line up to a certain point.

Producing the B-21 will cost $20B for the next five years. The USAF is keeping the production count secret, but I doubt its more than 30.

So, that's $670M per plane (give or take). Not counting R&D.

Yes, that's WAY WAY WAY to much for a smaller tanker.

Find some way to reduce the price by 2X and it's still WAY to much.
https://www.airforcemag.com/producing-n ... ough-2027/

kitplane01 wrote:

Producing the B-21 will cost $20B for the next five years. The USAF is keeping the production count secret, but I doubt its more than 30.

I don't know if I would call it "secret". As it stands right now, the USAF has been very vocal about wanting a minimum of 100 and 120 would be better. I did see a number of 134 put forward as being the best number accounting for the airframes used for training, flight testing and depot maintenance. I think it's more a matter of how much $$ will be put forward by Congress. I doubt they learned their lesson from the B-2 and the F-21. Time will tell.

kitplane01 wrote:

Producing the B-21 will cost $20B for the next five years. The USAF is keeping the production count secret, but I doubt its more than 30.

AIR FORCE MAKES IT OFFICIAL – MINIMUM OF 100 B-21 RAIDER BOMBERS NEEDED
https://sofrep.com/fightersweep/air-for ... rs-needed/

Also $20B is only the budget for the next 5 years of the program. The USAF has always stated minimum of 100 B-21 bombers

US$203 billion to develop, purchase and operate for 30 years.

https://www.bloomberg.com/news/articles ... get-so-far

Regarding the cost of a B-21 based tanker.

The KC-46 costs $239.8 million each.
https://www.gao.gov/assets/700/699661.pdf

The MQ-25 program cost is $11.1 billion for 76 tankers or $155 million per drone.
https://www.fool.com/investing/2021/07/ ... es-flight/

The USAF would happily pay $400 million each for an unmanned and relatively stealthy tanker based on the B-21. While it may have around half the fuel capacity of the KC-46 it will have 4-5 times the capacity of the MQ-25 tanker.

The key difference is the KC-46 will get shot down with 2 pilots KIA if it goes near the front line. A big price premium can be justified for unmanned and a bit of stealth.

I doubt a boom could be installed onto an aircraft smaller than the B-21. Even the larger B-2 bomber is only 21m long. I'm sure Boeing could scale up the MQ-25 tanker and fit a boom to it and the purchase cost per aircraft might be cheaper. However having the tanker based off the B-21 would reduce the production and sustainment costs of the bomber version due to a larger economy of scale.

RJMAZ wrote:

The KC-46 costs $239.8 million each.
https://www.gao.gov/assets/700/699661.pdf

Based on the last few lots of KC-46 acquisition, the flyaway cost is hovering around $145M.

The key difference is the KC-46 will get shot down with 2 pilots KIA if it goes near the front line. A big price premium can be justified for unmanned and a bit of stealth.

It's doubtful that any tanker that is loitering or flying refueling tracks near the front lines, would be survivable. This is why the USAF has moved away from the notion of stealth for the KC-Z.

It still may be a desirable attribute, but it's never going to be like a penetrating attack mission, in and out. It has a boom that is difficult to conceal on radar. And it can't attack the systems designed to detect it. It's just not a very feasible concept, that invisible tankers will be hanging around in contested airspace.

RJMAZ wrote:

The key difference is the KC-46 will get shot down with 2 pilots KIA if it goes near the front line.

Not wanting to lose two pilots is the reason the USAF is going for the one pilot/one boomer concept for Peggy. Since the boomer is apparently free real estate, there’ll still be someone to raise the gear and be the pilot’s cheerleader and coffee grabber, but you’ll only lose one pilot. Problem solved!

RJMAZ wrote:

I doubt a boom could be installed onto an aircraft smaller than the B-21.

I doubt it can even be installed on a B-21. Booms are very long; even a “small” KC-135 boom is 30-odd feet long retracted, so If you mount it where the bomb bay goes there’s unacceptable overlap between the pair (the F-22’s receptacle is 25 feet behind the nose) and the boom can’t sit flush against the fuselage. If you mount it on the back you’ll have a jet with a very long stinger whose rotation angle limitations would make the 739ER look like a STOL jet in comparison.

The only way a B-21 could be a tanker is with a hose reel compartment/fuel tank in the bomb bay. And who would they refuel? USN/USMC. Fat chance the USAF will essentially “give” their iron to the Navy. If the USAF could use probes that could actually work, barring the logistical/bureaucratic hurdles.

Avatar2go wrote:

It's doubtful that any tanker that is loitering or flying refueling tracks near the front lines, would be survivable. This is why the USAF has moved away from the notion of stealth for the KC-Z.

It still may be a desirable attribute, but it's never going to be like a penetrating attack mission, in and out. It has a boom that is difficult to conceal on radar. And it can't attack the systems designed to detect it. It's just not a very feasible concept, that invisible tankers will be hanging around in contested airspace.

I never said a B-21 based tanker would be invisible. I clearly mentioned no stealth coatings. It will still have a tactically significant radar cross section reduction compared to the KC-46

The refueling tanker circuit position are based on the chance of detection and the risk they are willing to take with the crew.

If a KC-46 can be detected 300nm away while refueling a B-21 based tanker might be detected 150nm away while refueling. This allows the fighters to penetrate 150nm deeper into enemy territory.

The USAF might accept a 0.1% chance of a crewed KC-46 being shot down. They might be willing to accept a 1% chance of an unmanned B-21 based tanker being shot down. The B-21 based tanker can now come an additional 50nm closer to the enemy. The fighters are now penetrating 200nm deeper into enemy territory.

Another example. Take an F-35 that has just dogfighted over enemy territory and has very low fuel. They may accept a 10% risk to the unmanned tanker if it meant saving the F-35 and the pilot.

The force multiplier effect by having a top up tanker this much closer is huge. The fighters are no longer spending time doing the 300nm transit to the KC-46. They will be back in the fight in half the time. 10 B-21 based tankers could then make 200 F-35 fighters feel like a force of 400 fighters. Dozens of KC-46 can sit back at a safe distance carrying the bulk of the fuel.

So there is an incentive to make the tanker as stealthy as possible but there is also the point of diminishing returns. There is no point giving the tanker a 0.001m2 radar cross section if the boom adds say 0.1m2 and when in use it adds 1m2.

While they might not mention stealth you can clearly see the MQ-25 is moderately stealthy. The chine down the sides to reduce the side RCS. The hidden air intake up top. The V tails. Even the exhaust is square like the F-117 for reduced IR signature.

Avatar2go wrote:

The tactical tanker is supposed to be able to refuel aircraft operating from forward improvised rough & unimproved airfields. The concept is valid

I am not convinced the concept is valid.

Aircraft are high value targets. You would not want to forward deploy them unless you really have to. Just ask Russia how their airbases get shelled by artillery and rockets. So with that in mind a forward deployed tanker makes little sense.

But let’s say that things go really bad and you do need forward deployment. Would it not be fair to say that under such conditions your aircraft would likely run out of ammo before they run out of gas?

LyleLanley wrote:

I doubt it can even be installed on a B-21. Booms are very long; even a “small” KC-135 boom is 30-odd feet long retracted,

I agree with all of this and a solution can be found. The boom would have to be fully custom and would probably make up most of the development cost.

The bomb bay should be around 20 feet long to carry 6m long cruise missiles. The most aft point of the bomb bay should be quite close to the rear of the aircraft like the B-2 which is convenient for a boom. Half of the boom could retract into bomb bay to help with rotation angle.

petertenthije wrote:

I am not convinced the concept is valid.

Aircraft are high value targets. You would not want to forward deploy them unless you really have to. Just ask Russia how their airbases get shelled by artillery and rockets. So with that in mind a forward deployed tanker makes little sense.

But let’s say that things go really bad and you do need forward deployment. Would it not be fair to say that under such conditions your aircraft would likely run out of ammo before they run out of gas?

I meant the concept was valid in the sense that the KC-390 might be able to operate from those airfields. The KC-46 has unimproved capability, in that they can fly in a portable operations support system. But it doesn't have rough field capability, it needs a paved airstrip. KC-390 could work on rough fields.

As far as forward deployment, it just depends. I think the idea is that forces would need to disperse to remote airstrips due to missile attack on the main bases, similar to what Ukraine did. But certainly there is a limit where you just hold out your forces for destruction, if too far forward.

JayinKitsap wrote:

texl1649 wrote:

There remains no observable facts supporting the assertion the USAF intends to fund development of a stealthy tactical tanker capability, let alone that the B-21 could be modified to fit such a role.

Anything approaching an off the shelf solution with multi role capabilities and simple acquisition should be considered, whether it come from Lockheed/Airbus, Embraer, Boeing or someone else as I don’t think ongoing reliance on exclusively the KC-46 to replace the huge KC-135 fleet makes any sense. The decades of futility to get the Pegasus into service finally should militate the acquisition machinery to go for ‘simple’ vs. ‘new stealthy concept.’

I would go further, in that for USAF tankers the need to go past KC-Y where 2/3 of the KC-135 will have been replaced is relatively low. Besides, a number of large factors will need to play out for a decade or more for the planners to have a clear picture:

-B-52 Re-engine - with 20+% more range, far less need to refuel. Also only 76 in total.
-B-1 and B-2 retirements
-B-21 actual experience
-The KC-46 has improved characteristics compared to the KC-135, allowing it to operate closer to the front line - but how much more.
-How the MQ-25 drone performs and the overall drone tanker operations
-Refueling of drones, the best size for this and operational such as "Mother Ship" concepts Would smaller MQ-25 type drones shuttle from the mother ship or ?
-Total fleet size and percent of fleet that are drones.

There are a lot of moving targets here, it might be a decade before the Air Force realizes the specific specs for this new tanker. Until then it is more of wish list placeholders.

Moving to (smaller) drones/stealthy drones/bombers like the B-21 will only increase refueling needs, net, and I don’t think even for the B-52 missions the total orbiting tankers/backup tankers will decrease by much based on the fuel savings. Net-net, between more UCAVS/UAV’s, less B-1’s, many B-21’s, pacific facing operations, and more fuel for stealthy types not carrying drop tanks period (NGAD etc.), I don’t see a near-mid term significant drop in refueling missions/needs for the USAF vs. the past 20-30 years.

What the USAF can’t do is just wait to define some sort of requirements even for 5 to 10 years. Even the simplest procurement in this space of a new type will take 10-20 years.

RJMAZ wrote:

The bomb bay should be around 20 feet long to carry 6m long cruise missiles. The most aft point of the bomb bay should be quite close to the rear of the aircraft like the B-2 which is convenient for a boom. Half of the boom could retract into bomb bay to help with rotation angle.

That’s clever, but heavy duty fuel lines aren’t conducive to retracting and bending at the same time. The boom pivot area is already magic.

The mechanics involved in making your concept work would make the C-5’s kneeling systems look quaint, by comparison.

LyleLanley wrote:

That’s clever, but heavy duty fuel lines aren’t conducive to retracting and bending at the same time. The boom pivot area is already magic.

The mechanics involved in making your concept work would make the C-5’s kneeling systems look quaint, by comparison.

Again I agree. An advantage is the weapons bay is a large void and is quite long in the required direction. It also has very strong mounting locations. I would expect a cleansheet retracting boom to use the fuel itself as the hydraulic solution so no bending hoses would be required.

As this unmanned tanker will primarily be refueling fighters I am sure the USAF will accept lower fuel flow rates if bending hoses is required. The probe and drogue hoses have incredible flexibility to retract over 20 metres into a small pod. I am sure the USAF would be happy with say double the flow rate of probe and drogue as it will only be an extra 30 seconds at the boom. I am sure they would easily find a hose that can provide 5m of retraction and bend in a large weapons bay.

I assume the now empty cockpit area of the B-21 will be located just forward and slightly above the weapon bay position like in the B-2. There could be 10 metres of length inside the B-21 to play with.

It'd be cheaper to give next gen aircraft longer legs than to develop a tanker that can somehow pull of LO re-fueling.

DigitalSea wrote:

It'd be cheaper to give next gen aircraft longer legs than to develop a tanker that can somehow pull of LO re-fueling.

I strongly disagree. To increase combat radius by 50% while maintaining agility and speed requires a massive 200+% increase in cost.

NGAD is probably the perfect example here as it has the long legs. It is reported to have a 1,000nm combat radius which is 50% higher than the F-35. It also has two F-35 sized engines. It is safe to say it will weigh double that of the F-35. To get a fueled and armed aircraft weighing 50,000kg to go supersonic and maintain good agility is why it is said to cost 5+ times as much as a single F-35A.

the service was talking about “multiple” hundreds of millions. “This is a number that’s going to get your attention,” Kendall said. “It’s going to be an expensive airplane.”

https://www.defensenews.com/air/2022/04 ... ns-apiece/

So it is not cheaper to give an aircraft longer legs. It is actually cheaper to just buy one $300 million B-21 tanker to top up a dozen $100 million F-35 aircraft. For that same $1.5 billion you might only get 3-4 NGAD fighters. I would take 12 F-35 over 3-4 NGAD fighters for the vast majority of missions.

There of course will be some missions that require Mach 2 speeds at 60,000ft but it is MUCH cheaper to use the F-35 combined with an unmanned tanker.

RJMAZ wrote:

I never said a B-21 based tanker would be invisible. I clearly mentioned no stealth coatings. It will still have a tactically significant radar cross section reduction compared to the KC-46

The refueling tanker circuit position are based on the chance of detection and the risk they are willing to take with the crew.

If a KC-46 can be detected 300nm away while refueling a B-21 based tanker might be detected 150nm away while refueling. This allows the fighters to penetrate 150nm deeper into enemy territory.

l think the point you're missing is that contested airspace includes any distance where the adversary can realistically target and shoot. Large tankers won't be operating in that airspace, and stealth would not save them if they did, even if it were possible.

While they might not mention stealth you can clearly see the MQ-25 is moderately stealthy. The chine down the sides to reduce the side RCS. The hidden air intake up top. The V tails. Even the exhaust is square like the F-117 for reduced IR signature.

I think there is a role for stealth with small tankers like the MQ-25 that could operate in contested airspace, as an attributable asset. As you said, the stealth in that case just has to reduce the risk, not eliminate it, because you are willing to accept the loss. That will never be true of large tankers. They will always be protected assets.

texl1649 wrote:

JayinKitsap wrote:

texl1649 wrote:

There remains no observable facts supporting the assertion the USAF intends to fund development of a stealthy tactical tanker capability, let alone that the B-21 could be modified to fit such a role.

Anything approaching an off the shelf solution with multi role capabilities and simple acquisition should be considered, whether it come from Lockheed/Airbus, Embraer, Boeing or someone else as I don’t think ongoing reliance on exclusively the KC-46 to replace the huge KC-135 fleet makes any sense. The decades of futility to get the Pegasus into service finally should militate the acquisition machinery to go for ‘simple’ vs. ‘new stealthy concept.’

I would go further, in that for USAF tankers the need to go past KC-Y where 2/3 of the KC-135 will have been replaced is relatively low. Besides, a number of large factors will need to play out for a decade or more for the planners to have a clear picture:

-B-52 Re-engine - with 20+% more range, far less need to refuel. Also only 76 in total.
-B-1 and B-2 retirements
-B-21 actual experience
-The KC-46 has improved characteristics compared to the KC-135, allowing it to operate closer to the front line - but how much more.
-How the MQ-25 drone performs and the overall drone tanker operations
-Refueling of drones, the best size for this and operational such as "Mother Ship" concepts Would smaller MQ-25 type drones shuttle from the mother ship or ?
-Total fleet size and percent of fleet that are drones.

There are a lot of moving targets here, it might be a decade before the Air Force realizes the specific specs for this new tanker. Until then it is more of wish list placeholders.

Moving to (smaller) drones/stealthy drones/bombers like the B-21 will only increase refueling needs, net, and I don’t think even for the B-52 missions the total orbiting tankers/backup tankers will decrease by much based on the fuel savings. Net-net, between more UCAVS/UAV’s, less B-1’s, many B-21’s, pacific facing operations, and more fuel for stealthy types not carrying drop tanks period (NGAD etc.), I don’t see a near-mid term significant drop in refueling missions/needs for the USAF vs. the past 20-30 years.

What the USAF can’t do is just wait to define some sort of requirements even for 5 to 10 years. Even the simplest procurement in this space of a new type will take 10-20 years.

My point was that we are entering a period possibly as significant as the dawn of the Jet age. Twenty-five years from now will drones comprise 20% of the fleet, or 60%. The B-21 has far different requirements than the B-1 for refueling - as to distance, transferred fuel, and the like. The 3rd batch of tankers will need to be appropriate for that mission. Smaller aircraft probably will refuel using H & D not the boom, will need more frequent refueling.

The tech around the next generation fleet needs to be sorted out, for example the MQ-25 is designed for a relatively simple task but it is essential to get the design and procedures around operating on the flight deck correct. It's going to be Gen 3.0 before all the issues are mostly solved, Once that is covered, autonomous fighters / wing men, transports, reconnaissance will follow onto the carrier deck.

KC-X played catch-up with a long delayed program including the Drunyun Lease fiasco, KC-Y appears generally on time, but KC-Z will be for the future tanker to cover those areas outside of the KC-46 capabilities.

VMCA787 wrote:

kitplane01 wrote:

Producing the B-21 will cost $20B for the next five years. The USAF is keeping the production count secret, but I doubt its more than 30.

I don't know if I would call it "secret". As it stands right now, the USAF has been very vocal about wanting a minimum of 100 and 120 would be better. I did see a number of 134 put forward as being the best number accounting for the airframes used for training, flight testing and depot maintenance. I think it's more a matter of how much $$ will be put forward by Congress. I doubt they learned their lesson from the B-2 and the F-21. Time will tell.

Sure. True. But what I wrote was they are keeping the production count for the next 5 years secret, as can be found in the provided link.

RJMAZ wrote:

The KC-46 costs $239.8 million each.
https://www.gao.gov/assets/700/699661.pdf

The MQ-25 program cost is $11.1 billion for 76 tankers or $155 million per drone.
https://www.fool.com/investing/2021/07/ ... es-flight/

The USAF would happily pay $400 million each for an unmanned and relatively stealthy tanker based on the B-21. While it may have around half the fuel capacity of the KC-46 it will have 4-5 times the capacity of the MQ-25 tanker

The MQ-25 program has two goals: (1) tanking and (2) reseach into drones-from-carriers. If the only goal was #1 it would be cheaper to just buy more F-18s.

No nation in the history of the world has paid $400M for any tanker bought in any real number. Not one. Not ever.

I'll start believeing the B-21 based tanker fantasy when you provide a link saying the USAF is actually interested in a B-21 based tanker. Not some "in the distant future stealth tankers would be nice" but a real USAF official using the B-21 name and saying tanker.

kitplane01 wrote:

The MQ-25 program has two goals: (1) tanking and (2) reseach into drones-from-carriers. If the only goal was #1 it would be cheaper to just buy more F-18s.

Even if the MQ-25 only pass gas, it is still cheaper than buying more F-18 cause you have one less engine and one less pilot to maintain.

OK, maybe not a whole pilot, as you still need a drone operator. Let's say 1/3 rd of a pilot who don't need 20/20 vision.

bt

bikerthai wrote:

kitplane01 wrote:

The MQ-25 program has two goals: (1) tanking and (2) reseach into drones-from-carriers. If the only goal was #1 it would be cheaper to just buy more F-18s.

Even if the MQ-25 only pass gas, it is still cheaper than buying more F-18 cause you have one less engine and one less pilot to maintain.

OK, maybe not a whole pilot, as you still need a drone operator. Let's say 1/3 rd of a pilot who don't need 20/20 vision.

bt

I wondered that too.

F-18:
already has a support infrastructure
already has a training infrastructure
already has a parts supply on the boat
F-18 parts are common and made in quantity

MQ-25
Only need to fuel and maintain one engine
Does not have an insturment panel or ejection seat to maintain
MQ-25 parts are bespoke, and made in very small quantity

If an F-18 costs $70M less to produce, and you're gonna fly it 200 hours for 25 years, the it would need to cost $11,000 per hour more to break even. And because interest rates are expected to be positive over the next 25 years, it would in fact be more than $11,000/hour.
How much more depends on interest rates.

My uneducated guess is that the MQ-25 will overall cost more than F-18s, and be less useful than F-18s. So I hope they learn a lot from the experience, because I think that they are paying a lot for the knowldge.

kitplane01 wrote:

The MQ-25 program has two goals: (1) tanking and (2) reseach into drones-from-carriers. If the only goal was #1 it would be cheaper to just buy more F-18s.

A single MQ-25 can offload more fuel at range than two F-18 buddy tankers.

So now you have lower purchase price. 1 engine instead of 4. One drone operator instead of two proper pilots. It is significantly cheaper to go with the drone tanker.

If you go without tanking altogether then the Hornets have a lower combat radius and now the $10 billion carrier battle group is at higher risk.

The buddy tanking system is really only an emergency solution it is not useful for long range interdiction missions. The Hornet buddy tanker consumes a significant amount of its own fuel. For instance the MQ-25 can offload 7,250 kg of fuel at 500nm. While the Hornet buddy tanker might start off with around 12,000kg it will need two thirds of that fuel to travel 500nm away from the carrier and back.

As the radius increases the MQ-25 offload advantage will grow. At 900nm away from the carrier the buddy tanker will need all of its fuel for itself effectively making a ferry flight. The Hornet ferry range is 1,800nm. While the MQ-25 will still have more than 3,000kg of fuel to offload. Two MQ-25 tankers and a pair of F-35C could easily hit a target 1,000nm away from the carrier without a problem. The carrier probably couldn't handle the weight of a supersonic, agile, stealth fighter with 1,000+nm combat radius on internal fuel.

kitplane01 wrote:

No nation in the history of the world has paid $400M for any tanker bought in any real number. Not one. Not ever.

Inflation. You could buy an aircraft carrier in the 1950's for the price of what the USAF paid for a single F-22.

kitplane01 wrote:

If an F-18 costs $70M less to produce,

This is just a temporary delta. You are comparing a mature production line with an initial test and development batch. There's lots more to a man fighter than just the frame. The oxygen system itself is a maintenance item not needed on the UAV.

The MQ-25 is made using the digital manufacturing design an process that to my knowledge, have not been ported over to the F-18 line. Praobably not until/if they win the India competition.

Ultimately the MQ-25 will become a sensor platform as well, something that an F-18 is not efficient at performing.

Consider a sensor platform who's loiter time is not limited by the fatigue of the pilot, just the oil burn rate of the engine.

bt

RJMAZ wrote:

kitplane01 wrote:

The MQ-25 program has two goals: (1) tanking and (2) reseach into drones-from-carriers. If the only goal was #1 it would be cheaper to just buy more F-18s.

A single MQ-25 can offload more fuel at range than two F-18 buddy tankers.

So now you have lower purchase price. 1 engine instead of 4. One drone operator instead of two proper pilots. It is significantly cheaper to go with the drone tanker.

If you go without tanking altogether then the Hornets have a lower combat radius and now the $10 billion carrier battle group is at higher risk.

The buddy tanking system is really only an emergency solution it is not useful for long range interdiction missions. The Hornet buddy tanker consumes a significant amount of its own fuel. For instance the MQ-25 can offload 7,250 kg of fuel at 500nm. While the Hornet buddy tanker might start off with around 12,000kg it will need two thirds of that fuel to travel 500nm away from the carrier and back.

As the radius increases the MQ-25 offload advantage will grow. At 900nm away from the carrier the buddy tanker will need all of its fuel for itself effectively making a ferry flight. The Hornet ferry range is 1,800nm. While the MQ-25 will still have more than 3,000kg of fuel to offload. Two MQ-25 tankers and a pair of F-35C could easily hit a target 1,000nm away from the carrier without a problem. The carrier probably couldn't handle the weight of a supersonic, agile, stealth fighter with 1,000+nm combat radius on internal fuel.

kitplane01 wrote:

No nation in the history of the world has paid $400M for any tanker bought in any real number. Not one. Not ever.

Inflation. You could buy an aircraft carrier in the 1950's for the price of what the USAF paid for a single F-22.

Can you please show me a payload range chart of an MQ-25, or for that matter an F-18. Or any source that says how much an F-18 can offload at 500nm? I'm willing to be educated, and you might be right, but I'd like to see a source.

kitplane01 wrote:

RJMAZ wrote:

A single MQ-25 can offload more fuel at range than two F-18 buddy tankers.

Can you please show me a payload range chart of an MQ-25, or for that matter an F-18. Or any source that says how much an F-18 can offload at 500nm? I'm willing to be educated, and you might be right, but I'd like to see a source.

I can confirm this, it's been widely reported in articles about the MQ-25. It can offload about 16,000 pounds of fuel at 500 nm, compared to an F-18 buddy store of about 8,000 lbs.

An F-18 buddy store can top off one other F-18, that's why it's called a buddy store. The MQ-25 can do two. At lesser ranges, it can do four. The USN spec was two at maximum range, four in orbit above the carrier for returning aircraft.

The MQ-25 gives the USN a lot more flexibility in terms of positioning fuel, since it can loiter, as well as costs of operations. For long range operations, they would send 2 or 3 MQ-25 ahead of a 4-aircraft sortie, then 2 or 3 behind. For carrier orbit, 1 MQ-25 is always up for the same sortie, plus one always on the deck in standby.

kitplane01 wrote:

Can you please show me a payload range chart of an MQ-25, or for that matter an F-18. Or any source that says how much an F-18 can offload at 500nm? I'm willing to be educated, and you might be right, but I'd like to see a source.

Here you have the data points to create the payload range curve.

Super Hornet holds a giveaway fuel load of 12,000lb (5,443kg) on a two-hour cycle, 15,000lb (6,803kg) on a normal cycle and 25,000lb (11,339kg) on a short cycle.

https://www.armadainternational.com/202 ... m-for-now/

You probably need help how to create it. The 25,000lb offload figure will be at a combat radius at close to zero nautical miles. The 12,000lb offload is after 2 hours of flight time. The Super Hornet cruises at only 300 knots on a good day. At 300 knots an aircraft travels 300 nautical miles in one hour. So i
the 2 hour cycle it gives a combat radius of 300 nautical miles.

You can now see how steep the payload range curve is for the Super Hornet buddy tanker. Starting with 25,000lb of offload which would be comparable to the MQ-25 and dropping to only 12,000lb offload by 300nm.

The MQ-25 is 16,000lb at 500nm. You can calculate how much the Super Hornet offloads at 500nm. Now calculate the offload at 600nm and 700nm. The MQ-25 now offloads many multiples of the Super Hornet. So your cost comparison is pointless. You need two Hornet buddy tankers to do the job of the MQ-25 and aircraft carrier is limited on space.

Pylon drag
The drag created by the 4 drop tanks and the central buddy refueler is extremely high. Remember the Super Hornet pylons are canted slightly outwards due to the design flaw causing weapon separation issues. This causes lots of drag.

Engines
The two Super Hornet F414 engines at 100% dry thrust is pushing out 115kn of thrust versus the single 44kn engine in the MQ-25. Also look at the fuel consumption of the engines. The F414 has a low bypass ratio of 0.25:1 yet the AE 3007 is a high bypass ratio of 5:1

Wings
The wings of the MQ-25 give a much better lift to drag ratio. Higher span and less wing sweep. This means less thrust is needed to cruise at the same flying weight.

Would a remote boom operator, located hundreds and potentially thousands of miles away, have the situational awareness to avoid something like this?

https://www.youtube.com/watch?v=vbQ9LXZwJ78

Hopefully, but this guy was right there and he didn’t avoid it either: the NATO E-3 pilot did the work. Equally hopeful a remote boom wouldn’t stutter like this guy when blurting out ‘the B-word’.

Truth be told, this incident is a better example of why remote pilots can’t do time-sensitive tasks (satellite link has a 1-2 second lag) such as takeoff, landing, and in this case AR, then an example of why remote boom is a bad idea - which I don’t think anyone has proposed. That one second of lag counts when the KC-135’s autopilot attempts to kill you and her crew.

With the government of Brazil being "weird" about the war in Ukraine, would the US reward a Brazilian company with a military contract?

RJMAZ wrote:

https://www.defensenews.com/air/2022/04 ... ns-apiece/

So it is not cheaper to give an aircraft longer legs. It is actually cheaper to just buy one $300 million B-21 tanker to top up a dozen $100 million F-35 aircraft. For that same $1.5 billion you might only get 3-4 NGAD fighters. I would take 12 F-35 over 3-4 NGAD fighters for the vast majority of missions.

Why on Earth would the USAF need a B-21 tanker?

Unless we're assuming a tanker will always be in range of whatever's on patrol and that there's no threat to the tanker, yes, it would be cheaper to give the NGAD longer legs for its on station time.

DigitalSea wrote:

Why on Earth would the USAF need a B-21 tanker?

Because the KC-46 will get shot down and you've lost 3 crew.

Hi guys,
I'm wondering whether any other countries would be interested in developing a 'tactical tanker' like this ... I reckon the RAAF would be IF they eventually end up with the small number of B-21s that's been whispered about.
Israel? Japan? South Korea? I can't see any European nation buying them, nor any Gulf state.
Bluntly, if a 'tactical tanker' is based on the B-21, I can't imagine the Americans allowing its purchase by any other country, except perhaps if Australia did buy the B-21 as well - which I think is unlikely IMHO.
Take care,
Bunumuring.

DigitalSea wrote:

, it would be cheaper to give the NGAD longer legs for its on station time.

It may be cheaper to have NGAD have a probe like all the NAVY planes. Much easier to develope and deploy quantities of semi-stealthy, semi-disposable, drones than make a B-21 stealth tanker.

bt

Apparently, the USAF has decided on the use of a BWB for the next Cargo/Tanker aircraft.

https://www.airandspaceforces.com/air-f ... t-by-2027/

Egad, that's an aggressive time line. Wonder if they will go small batch dual source like with NGAD.

bt

VMCA787 wrote:

Apparently, the USAF has decided on the use of a BWB for the next Cargo/Tanker aircraft.

https://www.airandspaceforces.com/air-f ... t-by-2027/

Important to note this is a research effort that is charged with reducing the USAF climate footprint. One way to do that is with BWB designs. This project is developing an experimental prototype, to gain experience and test results for the type.

It is very far removed from the notion of a USAF operational tanker or cargo aircraft. It's possible that if the prototype is successful, development could continue toward a production aircraft. But we are at least a decade out from anything like that.

Not really sure why this gets hyped so much in the press. The USAF looks at many prototype designs, the majority don't become operational aircraft. It will be awhile before we know about this one.

Avatar2go wrote:

Not really sure why this gets hyped so much in the press.

Reporters are people. I’m sure they’re as tired of writing an article starting with “In the latest setback to the KC-46 program…” as we are of reading it.

LyleLanley wrote:

Avatar2go wrote:

Not really sure why this gets hyped so much in the press.

Reporters are people. I’m sure they’re as tired of writing an article starting with “In the latest setback to the KC-46 program…” as we are of reading it.

The two may be related. If the press believes their own narrative, then the KC-46 is a failure and the USAF desperately needs a replacement platform. It doesn't seem to matter what the USAF actually says, or what the aircraft actually does. So they may see BWB as the needed solution to their alleged problem. But as I said, we won't know that for awhile yet.

They have to start somewhere.

If we believe future airlines will also go to BWB then this is a good a start as any for full scale R&D work.

bt