Your Nation's Air Force Mark III: Best Korea Edition

[Austria-Bohemia-Hungary]

*Chibi!B-2.

Now back to my original question: Could the weapon's bay be modified into a fuel tank to create a stealth tanker aircraft?

Are you afraid the MegaS-400 will get your tankers from 500 km's away or? <.<

[The Manticoran Empire]

Now back to my original question: Could the weapon's bay be modified into a fuel tank to create a stealth tanker aircraft?

Are you afraid the MegaS-400 will get your tankers from 500 km's away or? <.<

I'm worried about a number of things, mostly SAMs and fighters.

[Gallia-]

Both ATA would've had external pylons. Just attach a Super Hornet style tanker pod with a drogue and buff up the squadron strength by like 3-4 airframes. This is what A-6 squadrons did.

[Connori Pilgrims]

Now back to my original question: Could the weapon's bay be modified into a fuel tank to create a stealth tanker aircraft?

Are you afraid the MegaS-400 will get your tankers from 500 km's away or? <.<

TBF, a similar rationale is behind the US Navy's current unmanned CBARS effort. Although its less uber-S-400s, and more ching-chong and ivan trololol uber-BVRAAM-armed J-20s and Su-57 sniping away yankee F-35C and F/A-18E/Fs' tanker and AEW&C support from under them.

[Iltica]

Its really anachronistic, but what do you guys think of the idea of using a tail-dragging landing gear on a modern (last 25 years) strike-fighter to improve rough-field performance?
Or is that a myth? Its probably a myth isn't it...

[Taihei Tengoku]

I would think a taildragger increases the chances of a tailstrike, and since the going parts are in the back of the plane in most jets...

[Iltica]

Idk, read somewhere the nosewheels have a tendency to get stuck on rough surfaces but in that context they were talking about front engines prop planes which would have more weight over that wheel.
Being more back heavy might reverse it you think?

Not sure what you mean by the tail strike bit, how can you have a tail strike if there's a wheel under it?

[The Akasha Colony]

Its really anachronistic, but what do you guys think of the idea of using a tail-dragging landing gear on a modern (last 25 years) strike-fighter to improve rough-field performance?
Or is that a myth? Its probably a myth isn't it...

The fact that no one has done it or even seriously proposed it should be sufficient indication of its lack of merit.

The biggest issue is jet blast, which is directed straight at the ground and then bounces back around the aircraft. This is a major problem when landing and taking off as it generally renders the aft control surfaces ineffective. It isn't totally insurmountable, but it's certainly undesirable.

Poor visibility is another issue that will crop up in rough field operations where a control tower will likely not be available to coordinate taxi operations at the airfield.

[Post War America]

Its really anachronistic, but what do you guys think of the idea of using a tail-dragging landing gear on a modern (last 25 years) strike-fighter to improve rough-field performance?
Or is that a myth? Its probably a myth isn't it...

The fact that no one has done it or even seriously proposed it should be sufficient indication of its lack of merit.

The biggest issue is jet blast, which is directed straight at the ground and then bounces back around the aircraft. This is a major problem when landing and taking off as it generally renders the aft control surfaces ineffective. It isn't totally insurmountable, but it's certainly undesirable.

Poor visibility is another issue that will crop up in rough field operations where a control tower will likely not be available to coordinate taxi operations at the airfield.

A continuation question: how much may the situation change if using turboprop type aircraft ala Super Tucano?

[Iltica]

For PWA: You could try a

For Akasha: Ass-dragging jets aren't unheard of, some early designs like the Attacker retained the older layout. Though it's engine is much further forward than modern designs have it.
My design is tailless if that helps at all, but maybe it would be better to use a double nose wheel or spread it out on a bogie?

[Post War America]

For PWA: You could try a

(Image)

For Akasha: Ass-dragging jets aren't unheard of, some early designs like the Attacker retained the older layout. Though it's engine is much further forward than modern designs have it.
My design is tailless if that helps at all, but maybe it would be better to use a double nose wheel or spread it out on a bogie?

Thanks for the advice but I was more asking the question to promote further discussion rather than fishing for an actual craft.

[The Akasha Colony]

For PWA: You could try a

(Image)

For Akasha: Ass-dragging jets aren't unheard of, some early designs like the Attacker retained the older layout. Though it's engine is much further forward than modern designs have it.
My design is tailless if that helps at all, but maybe it would be better to use a double nose wheel or spread it out on a bogie?

The few jet aircraft to use the arrangement such as the Attacker only did so because they were basically just jet-powered derivatives of propeller aircraft. In the case of Attacker, it was just a jet Spiteful.

Realistically, it doesn't matter much. A suitably wide track, robust oleo struts, and modestly sized tires will do fine. The Russians have bragged extensively about the rough field capability of MiG-29 and Su-27 but both use very standard landing gear arrangements. MiG-29 has a double nosewheel but Su-27, which is much heavier, does not. Both have conventional twin-post single-wheel main gear.

A continuation question: how much may the situation change if using turboprop type aircraft ala Super Tucano?

If it is a nose-mounted prop, then it will basically be the same as a piston-engined aircraft. There isn't much of an actual incentive to use a taildragger arrangement though. If you can't even manage a very basic airfield capable of supporting tricycle landing gear, you probably can't manage to operate any actual aircraft. Even small UAVs use tricycle gear.

[New Vihenia]

The VIhenian airforce "Shelenia Blanchett" touting her newest arsenal, the low observable tactical cruise missile "Elimea Varda"




Elimea Varda is our latest addition to our growing arsenal of precision guided munitions. This missile is designed to be "universal" Allow launch from air, ship and ground. The extended range (also strategic) variant (not depicted) Features extended wings, more powerful engine and lengthened fuel section is slated to replace the old Melona cruise missile already in service for over 30 years in our strategic aviation.



The missile features low observability achieved through use of special shaping and reduced infra red emmissions through use of turbofan engine. The guidance is based on combination of Tercom, NAVSAT and new precision gyroscope. terminal homing is to be done through Imaging Infra Red sensor using uncooled elements. Radar sensor is also considered for future variant including anti ship.

Our bombers are able to carry about 16-32 of the tactical version of the missile.

[Kassaran]

So, an issue I take to airborne ships of any type for combat that aren't aircraft of only a few tens of thousands of pounds at max:

1- what you'll need to crew the vessel will likely be great, taxing just how much your military can afford to train replacements for those who inevitably get shot down behind enemy lines.
2- once you're locked onto (which you will be), you'll be a sitting duck for the multiple Mach-3 missile salvos from the single element of lone interceptors some hundred kilommeters away, with only ECM and hard Countermeasures to boot.
3- once you're hit, you have little likelihood of recovery given how poor the vitality of most modern aircraft are
4- the costs of replacing a lost airship are going to be absolutely massive and will almost never justify their use.
5- the speeds at which most larger things can move at efficiently, are not cost efficient if you want them to be combat capable, and not efficient if you want loiter time.

All in all, seaborne aircraft carriers are great because they require almost no extra effort to stay in their element- the surface of the water. Airbases also require zero effort to stay on the ground. Airship carriers and any airships for that matter that go over traditional weights for most bombers fielded today face similar issues in conception as they are unable to easily remain in their element.

[Onekawa-Nukanor]

Would an A220/DefinitelyNotBombardierUSGovernment CSeries aircraft be suitable as a good basis for both tanker/transport (like a smaller A330 MRTT, or perhaps pure tanker) as well as an AEW platform? Not both in the same airframe but as the basis for two different types of aircraft.

I'm thinking for my "Armed Zealand" series of model aircraft I'm building (F-4J nearly done just need decals, F-15"H"mostly built) that it would be a good size for a significantly more militarised RNZAF (and NZDF in general) without going whole hog.

[The Akasha Colony]

Would an A220/DefinitelyNotBombardierUSGovernment CSeries aircraft be suitable as a good basis for both tanker/transport (like a smaller A330 MRTT, or perhaps pure tanker) as well as an AEW platform? Not both in the same airframe but as the basis for two different types of aircraft.

I'm thinking for my "Armed Zealand" series of model aircraft I'm building (F-4J nearly done just need decals, F-15"H"mostly built) that it would be a good size for a significantly more militarised RNZAF (and NZDF in general) without going whole hog.

It could function as one.

Whether it would be "good" depends on your requirements for the airframe.

It should probably be noted that there are no "pure" airliner tankers; pretty much every tanker aircraft currently in service still has most of its fuselage empty which means they all have significant space for cargo.

The A330 MRTT actually doesn't carry any extra fuel over the standard commercial A330, it just has the ability to deliver that fuel to other planes. Airbus developed extra tanks for use in the lower cargo deck but so far as I know no customer has taken that option as they have all been satisfied by its standard fuel capacity. The "multi-role tanker transport" is mostly just marketing on Airbus' part. KC-767, KC-135, KC-10, etc. can all carry cargo as they all have unobstructed main decks. Most of their lower decks are open too.

The one major exception I can think of is later variants of the Il-78, but this is mostly because it's an airlifter platform built around a rear door which was removed in later variants to improve mountings for fuel transfer equipment. This is mostly because the standard Il-76 could only transfer tiny amounts of fuel unless special tanks were fitted in the cargo hold,so deeper conversions were needed to transfer a useful amount of fuel. Airliner-derived tankers use side hatches for cargo which do not impede aerial refueling operations and are generally designed for large fuel loads anyway.

[Onekawa-Nukanor]

Would an A220/DefinitelyNotBombardierUSGovernment CSeries aircraft be suitable as a good basis for both tanker/transport (like a smaller A330 MRTT, or perhaps pure tanker) as well as an AEW platform? Not both in the same airframe but as the basis for two different types of aircraft.

I'm thinking for my "Armed Zealand" series of model aircraft I'm building (F-4J nearly done just need decals, F-15"H"mostly built) that it would be a good size for a significantly more militarised RNZAF (and NZDF in general) without going whole hog.

It could function as one.

Whether it would be "good" depends on your requirements for the airframe.

It should probably be noted that there are no "pure" airliner tankers; pretty much every tanker aircraft currently in service still has most of its fuselage empty which means they all have significant space for cargo.

The A330 MRTT actually doesn't carry any extra fuel over the standard commercial A330, it just has the ability to deliver that fuel to other planes. Airbus developed extra tanks for use in the lower cargo deck but so far as I know no customer has taken that option as they have all been satisfied by its standard fuel capacity. The "multi-role tanker transport" is mostly just marketing on Airbus' part. KC-767, KC-135, KC-10, etc. can all carry cargo as they all have unobstructed main decks. Most of their lower decks are open too.

The one major exception I can think of is later variants of the Il-78, but this is mostly because it's an airlifter platform built around a rear door which was removed in later variants to improve mountings for fuel transfer equipment. This is mostly because the standard Il-76 could only transfer tiny amounts of fuel unless special tanks were fitted in the cargo hold,so deeper conversions were needed to transfer a useful amount of fuel. Airliner-derived tankers use side hatches for cargo which do not impede aerial refueling operations and are generally designed for large fuel loads anyway.

The primary focus of the RNZAF in this Armed Zealand scenario is protecting both both itself and Australia. In this scenario, Australian states New South Wales and Victoria are their own independent hostile nation friendly with the USSR and then later on China. With the focus of regional defence rather than something more further abroad, the RNZAF is focused on keeping conflict as far from NZ shores as possible and engaging the enemy proactively rather than reactively where possible to achieve this. With the hostile Australia a large, economically well off nation it deploys a full blown modern military force generally along modern Russian/Chinese lines, but with a greater aerial and naval focus than perhaps these states because of their physical position and concerns over US assets surging into the area and therefore denying them any chance of a quick victory against their main rivals.

The A220 AEW would thus be used mainly to monitor the Tasman and hostile forces from this quarter in addition to, where needed focus on the larger NZ EEZ. Thus an aircraft with good (but not tremendous) range is preferred, especially for the EEZ tasking as well as being able to remain airborne for as long as possible, but small enough to operate from more regional runways and the like when required and low cost enough to ensure as many airframes as possible can be maintained as well as ability to self-deploy to Australia if and where required with minimum fuss. Same general qualities are desired for the A220 MRTT version. This would tie into a wider RNZAF goal of holding off enemy forces long enough for allies to pour into the area whilst keeping them as far from NZ as possible.

[The Akasha Colony]

The primary focus of the RNZAF in this Armed Zealand scenario is protecting both both itself and Australia. In this scenario, Australian states New South Wales and Victoria are their own independent hostile nation friendly with the USSR and then later on China. With the focus of regional defence rather than something more further abroad, the RNZAF is focused on keeping conflict as far from NZ shores as possible and engaging the enemy proactively rather than reactively where possible to achieve this. With the hostile Australia a large, economically well off nation it deploys a full blown modern military force generally along modern Russian/Chinese lines, but with a greater aerial and naval focus than perhaps these states because of their physical position and concerns over US assets surging into the area and therefore denying them any chance of a quick victory against their main rivals.

The A220 AEW would thus be used mainly to monitor the Tasman and hostile forces from this quarter in addition to, where needed focus on the larger NZ EEZ. Thus an aircraft with good (but not tremendous) range is preferred, especially for the EEZ tasking as well as being able to remain airborne for as long as possible, but small enough to operate from more regional runways and the like when required and low cost enough to ensure as many airframes as possible can be maintained as well as ability to self-deploy to Australia if and where required with minimum fuss. Same general qualities are desired for the A220 MRTT version. This would tie into a wider RNZAF goal of holding off enemy forces long enough for allies to pour into the area whilst keeping them as far from NZ as possible.

These are very nebulous "requirements."

I was mostly referring to more concrete specifications because they will actually define whether an airframe is suitable for a given role.

For instance, the proposed AEW&C aircraft would need to be able to fly, say, a 1,000 kilometer radius with enough onboard fuel for a 6-hour on-station time. This would mean a minimum of 4 aircraft for 24-hour coverage, or more likely 5-6 aircraft to account for maintenance. This means 5-6 aircraft per expected station, which multiplied by the expected number of stations gives the expected number of aircraft to be purchased (and thus the price).

From there you can look at whether or not an aircraft is suitable for that role. A220 would not be suitable for this example role as it lacks the range to meet the radius/on-station time requirements. It may or may not be suitable price-wise depending on your expected budget.

For a tanker, is the ~17,000 kg of fuel the A220 carries sufficient? This is less than 1/5th of the fuel load of a KC-135 and barely 1/10th the load of a KC-10, but much more than would be expected of a carrier tanker like S-3 or the requirements for MQ-25. I do not know what your fuel transfer requirements are so I cannot speculate much further as to whether this would be sufficient.

[Onekawa-Nukanor]

The primary focus of the RNZAF in this Armed Zealand scenario is protecting both both itself and Australia. In this scenario, Australian states New South Wales and Victoria are their own independent hostile nation friendly with the USSR and then later on China. With the focus of regional defence rather than something more further abroad, the RNZAF is focused on keeping conflict as far from NZ shores as possible and engaging the enemy proactively rather than reactively where possible to achieve this. With the hostile Australia a large, economically well off nation it deploys a full blown modern military force generally along modern Russian/Chinese lines, but with a greater aerial and naval focus than perhaps these states because of their physical position and concerns over US assets surging into the area and therefore denying them any chance of a quick victory against their main rivals.

The A220 AEW would thus be used mainly to monitor the Tasman and hostile forces from this quarter in addition to, where needed focus on the larger NZ EEZ. Thus an aircraft with good (but not tremendous) range is preferred, especially for the EEZ tasking as well as being able to remain airborne for as long as possible, but small enough to operate from more regional runways and the like when required and low cost enough to ensure as many airframes as possible can be maintained as well as ability to self-deploy to Australia if and where required with minimum fuss. Same general qualities are desired for the A220 MRTT version. This would tie into a wider RNZAF goal of holding off enemy forces long enough for allies to pour into the area whilst keeping them as far from NZ as possible.

These are very nebulous "requirements."

I was mostly referring to more concrete specifications because they will actually define whether an airframe is suitable for a given role.

For instance, the proposed AEW&C aircraft would need to be able to fly, say, a 1,000 kilometer radius with enough onboard fuel for a 6-hour on-station time. This would mean a minimum of 4 aircraft for 24-hour coverage, or more likely 5-6 aircraft to account for maintenance. This means 5-6 aircraft per expected station, which multiplied by the expected number of stations gives the expected number of aircraft to be purchased (and thus the price).

From there you can look at whether or not an aircraft is suitable for that role. A220 would not be suitable for this example role as it lacks the range to meet the radius/on-station time requirements. It may or may not be suitable price-wise depending on your expected budget.

For a tanker, is the ~17,000 kg of fuel the A220 carries sufficient? This is less than 1/5th of the fuel load of a KC-135 and barely 1/10th the load of a KC-10, but much more than would be expected of a carrier tanker like S-3 or the requirements for MQ-25. I do not know what your fuel transfer requirements are so I cannot speculate much further as to whether this would be sufficient.

Oh sorry, I didn't realise you were referring to a more hard numbers requirement and thought a more broad outline was desired and to be honest this is all I had. I haven't really developed my Armed Zealand situation RNZAF that hard on the specific and was expecting a more general answer.

However the example of a 1,000km on station requirement for and AEW has given me some food for thought and allow me to work on the concept some more, so thanks for the info.

EDIT: So after doing a bit of digging and comparison to its nearest large competitor the 737 AEW, its seems a A220 has at base similar range characteristics to a 737-700 the RAAF E-7 is based on (and is actually higher than the base range of a 737 by near 500km). Whilst the 737 AEW variant has significantly more range over the airliner (some 1,500km) and a generally lower cruise speed (834km/h to 760km/h) to add to endurance it seems like the A220 could be similarly modified to accept modifications to meet the RAAF quoted 10h mission endurance of their E-7 Wedgetails

If the A220 could be modified to cruise efficently at the same speed of 760km/h, that gives it roughly 8 hours of endurance with an unmodified range (assuming the speed change doesn't effect fuel efficiency). Of course I also have to consider traveling too and from the patrol path. At 1,000km radius the airliner doesn't make it by roughly 37ish minute assuming a 760km/h speed since it takes 1 hour 18 minutes to get out to 1,000km, but I feel like the airframe could be modified to accept plenty range to make it viable assuming it is as amenable to modification as the 737-700 is.

Now I making a lot of assumptions and I could just handwavium it if I really wanted to force it through, but I think my numbers are solid here and that for the AEW role the A220 could be reasonably assumed to be modified to perform the role required.

Still tinkering with the MRTT issue. When the A220 enters service it'll primarily be refueling F-35A as the main combat aircraft and its 17,000kg storage is only enough to refuel a single F-35A that is on empty and some of another before needed to turn around. I'm just not sure if its enough at the moment to keep a good long range (1,000km+) patrol out of a flight of 4 F-35s effectively. It might default to the A330 MRTT instead.

[The Akasha Colony]

Still tinkering with the MRTT issue. When the A220 enters service it'll primarily be refueling F-35A as the main combat aircraft and its 17,000kg storage is only enough to refuel a single F-35A that is on empty and some of another before needed to turn around. I'm just not sure if its enough at the moment to keep a good long range (1,000km+) patrol out of a flight of 4 F-35s effectively. It might default to the A330 MRTT instead.

A tanker doesn't need to completely replenish a receiving plane's completely empty fuel tank. The USN's goals for the MQ-25 program are for an aircraft that can deliver a total of 6,800 kg of fuel to a group of 4-6 aircraft at a range of 930 km. This obviously isn't enough to totally replenish any of the aircraft receiving fuel but it's enough to let them fly a few hundred kilometers further. Though obviously the USN is battling severe size and weight restrictions in order to get a tanker that fits aboard a carrier.

F-35A already has a combat radius beyond 1,000 km anyway. A top-up of 2,000 kg of fuel each would push this to 1,500 km without much trouble, which is a total of just 8,000 kg.

Big airline tankers are common today because the market has traditionally been driven by users like the USAF which operate large fleets of big support aircraft like strategic bombers, airlifters, and AEW&C aircraft. Contractors like Airbus and Boeing target their products at big contracts like KC-X which need to carry many tens of thousands of kilograms of transferable fuel to supply gas guzzlers like C-5 or E-3, which in turn demands a relatively large, long-legged platform like 767 or A330. Everyone else just buys off the shelf because no one else can put in enough orders to justify a special design tailored specifically to their needs so they just buy whatever is close enough.

Alternatively you could consider something like KC-130 or the fuel pods used by A400M, both of which carry more fuel than A220. Though both are also somewhat slower and KC-130 has a lower service ceiling than A220.

[Onekawa-Nukanor]

Still tinkering with the MRTT issue. When the A220 enters service it'll primarily be refueling F-35A as the main combat aircraft and its 17,000kg storage is only enough to refuel a single F-35A that is on empty and some of another before needed to turn around. I'm just not sure if its enough at the moment to keep a good long range (1,000km+) patrol out of a flight of 4 F-35s effectively. It might default to the A330 MRTT instead.

A tanker doesn't need to completely replenish a receiving plane's completely empty fuel tank. The USN's goals for the MQ-25 program are for an aircraft that can deliver a total of 6,800 kg of fuel to a group of 4-6 aircraft at a range of 930 km. This obviously isn't enough to totally replenish any of the aircraft receiving fuel but it's enough to let them fly a few hundred kilometers further. Though obviously the USN is battling severe size and weight restrictions in order to get a tanker that fits aboard a carrier.

F-35A already has a combat radius beyond 1,000 km anyway. A top-up of 2,000 kg of fuel each would push this to 1,500 km without much trouble, which is a total of just 8,000 kg.

Big airline tankers are common today because the market has traditionally been driven by users like the USAF which operate large fleets of big support aircraft like strategic bombers, airlifters, and AEW&C aircraft. Contractors like Airbus and Boeing target their products at big contracts like KC-X which need to carry many tens of thousands of kilograms of transferable fuel to supply gas guzzlers like C-5 or E-3, which in turn demands a relatively large, long-legged platform like 767 or A330. Everyone else just buys off the shelf because no one else can put in enough orders to justify a special design tailored specifically to their needs so they just buy whatever is close enough.

Alternatively you could consider something like KC-130 or the fuel pods used by A400M, both of which carry more fuel than A220. Though both are also somewhat slower and KC-130 has a lower service ceiling than A220.

Hmm, I do plan on the A400M being the RNZAF Airlifter so the fuel pods make sense which does make sense especially on a smaller budget, but I'm not sure if I'd want A400M airframes pulling double duty when I'd expect them to have enough to do with transport jobs. Definitely worth considering, and at the very least I can get the pods installed and have them act as tankers when and if needed, but still leave the majority of the tanking duties to the A220.

Also I might use the A220 as the basis for a Maritime Patrol craft as well. I never realised how many roles airliners in this size range can actually fill.

[The Akasha Colony]

Hmm, I do plan on the A400M being the RNZAF Airlifter so the fuel pods make sense which does make sense especially on a smaller budget, but I'm not sure if I'd want A400M airframes pulling double duty when I'd expect them to have enough to do with transport jobs. Definitely worth considering, and at the very least I can get the pods installed and have them act as tankers when and if needed, but still leave the majority of the tanking duties to the A220.

Also I might use the A220 as the basis for a Maritime Patrol craft as well. I never realised how many roles airliners in this size range can actually fill.

It isn't really unique to this size range though. It's simply a matter of modern electronics generally being able to fit into fairly small airframes compared to past iterations which demanded platforms like 707 or 767. The British attempt to shoehorn an AEW&C system into the Nimrod airframe was a dismal failure in the 1970s since it had barely half the MTOW of the E-3's 707 base, but nowadays compact AEW sets can fit into business jets much smaller than A220.

Once you pass this minimum size, almost any platform will do depending on your requirements.

The real question though is whether you expect to buy enough units of these aircraft to justify their development. Why buy an A220 MPA when you could potentially just buy P-1 or P-8? Or the notional A319 MPA?

[Triplebaconation]

You know NS isn't real, right?

[Kassaran]

You know NS isn't real, right?

Now our cover is blown and we have to find a whole new think-tank to go and haunt.

[Onekawa-Nukanor]

Hmm, I do plan on the A400M being the RNZAF Airlifter so the fuel pods make sense which does make sense especially on a smaller budget, but I'm not sure if I'd want A400M airframes pulling double duty when I'd expect them to have enough to do with transport jobs. Definitely worth considering, and at the very least I can get the pods installed and have them act as tankers when and if needed, but still leave the majority of the tanking duties to the A220.

Also I might use the A220 as the basis for a Maritime Patrol craft as well. I never realised how many roles airliners in this size range can actually fill.

It isn't really unique to this size range though. It's simply a matter of modern electronics generally being able to fit into fairly small airframes compared to past iterations which demanded platforms like 707 or 767. The British attempt to shoehorn an AEW&C system into the Nimrod airframe was a dismal failure in the 1970s since it had barely half the MTOW of the E-3's 707 base, but nowadays compact AEW sets can fit into business jets much smaller than A220.

Once you pass this minimum size, almost any platform will do depending on your requirements.

The real question though is whether you expect to buy enough units of these aircraft to justify their development. Why buy an A220 MPA when you could potentially just buy P-1 or P-8? Or the notional A319 MPA?

Fair point. Six aircraft would be the max (probably 5) and that does seem too low. Allied Australia could in theory team up and also support development of such a aircraft rather than buying an MPA off the shelf, but I doubt it would be much higher than the 12 P-8s that real life Australia so it could be a lot of hassle for 18 or less aircraft in total.