More KC-46A woes....

[KenV]

Originally Posted by BEagle

Travel in the A330MRTT (or even the A310MRTT) in transport role and you travel in normal wide-body airline comfort - the Voyager has a seat pitch extended to cope with troops in bulky clothing in particular.

Travel in the KC-46 in its transport role and it's the same windowless, palletised seating rendition-class comfort as the KC-135...

True enough. And the customer makes that decision. Not the manufacturer.

[tubby linton]

A passenger A330 can uplift 113t of fuel in the normal fuel structure without modification and leaving all of the holds and upper deck space empty.

[esscee]

A330-200 can have roughly that fuel figure on board, but not the longer fuselage A330-300 as the -300 does not have a Centre tank!

[tubby linton]

Originally Posted by esscee

A330-200 can have roughly that fuel figure on board, but not the longer fuselage A330-300 as the -300 does not have a Centre tank!

Airbus wil put in whatever you specify if you pay them enough.

[KenV]

Originally Posted by tubby linton

A passenger A330 can uplift 113t of fuel in the normal fuel structure without modification and leaving all of the holds and upper deck space empty.

Impressive capability. By comparison, KC-46 can only "uplift" 106 tons of fuel. The thing is, USAF does not care a wit how much gas a tanker can "uplift". It cares how much gas a tanker can offload over a range of distances and/or a range of on-station times. KC-46 meets or exceeds all of USAF's fuel offload requirements. Taking off with 7 extra tons of fuel is nice and all, but a larger, heavier tanker requires more powerful engines that consume more fuel. If the larger heavier tanker consumes 7 tons more fuel to perform its mission, that extra 7 tons is pointless. That's the very reason GEnX engines weren't put on the KC-46. They're more efficient but heavier and in the end, resulted in less fuel offload, which is what really matters.

In addition, if USAF is to be believed, KC-46 can "join the fight" and deliver that fuel in a much less benign airspace than legacy tankers. And can deliver that fuel to the entire range of US stealth aircraft. And after delivering fuel to fighters in the theater, KC-46 can perform an aeromedical evacuation of wounded personnel out of theater. KC-46 can also be used to carry "outsize" cargo, including vehicles, into and out of theater and move it around within the theater. It also has some in-theater electronic support capabilities I can't get into. Bottom line, for USAF it's the full military capability package that matters, not "fuel uplift".

One more time, USAF did not want a tanker that could only pass gas and only do it in a benign airliner environment. It wanted a tanker that could pass gas in a much more hostile environment than airliners operate in and wanted a tanker that could be used for military taskings other than just passing gas. Some customers other than USAF may want such capabilities, in which case they'll want to buy KC-46. Other customers may not want those capabilities, in which case they'll buy A330MRTT.

[KenV]

Originally Posted by tubby linton

Airbus wil put in whatever you specify if you pay them enough.

Two comments:

1. According to multiple sources, A330-200 and A330-300 have the same fuel capacity. So where does the -300 put the fuel that the -200 puts in the centerwing tank if -300 has no centerwing tank?

2. Consider that A330-200 and A330-300 also have the same Max Take Off Weight (MTOW). A longer fuselage means more empty weight, so less payload if MTOW is held constant. Adding a center tank on a -300 fuselage would then make no sense because the extra empty weight means you can't fill that center tank. By comparison, each time Boeing stretched the 767, it also increased the MTOW, thus increasing payload weight capacity to match the increase in payload volume.

[melmothtw]

By comparison, KC-46 can only "uplift" 106 tons of fuel.

That's changed then, every time I've been briefed by Boeing it has been 96 tonnes. Must have found an extra 10 tonnes from somewhere,,,

[KenV]

Originally Posted by melmothtw

That's changed then, every time I've been briefed by Boeing it has been 96 tonnes. Must have found an extra 10 tonnes from somewhere,,,

Tons vs Tonnes.

[BEagle]

The Pigosaurus has a max capacity of 212299lb (SG not stated though). Which is 96.3 Metric tonne, 94.78 imperial ton or 106.15 US ton.

More sales blah from ol'Bubba Boeing?

[melmothtw]

So the MRTT's 111 metric tonnes converts to 122 US tonnes then. If we're comparing apples and apples...

[Just This Once...]

Originally Posted by KenV

Adding a center tank on a -300 fuselage would then make no sense because the extra empty weight means you can't fill that center tank. By comparison, each time Boeing stretched the 767, it also increased the MTOW, thus increasing payload weight capacity to match the increase in payload volume.

I've no idea who does your math(s) but trying to play top-trumps with fuel/range/payload when you are holding the KC-46 card seems rather odd. Oh and the max weights for the A330 have increased significantly over the years.

In round figures, if you fill the A330-300 till every tank is full you still have well over 10 Tonnes of freight to offer in an otherwise empty and voluminous lower cargo bay, with the pax fit still installed above.

Somebody else can work out how much fuel a KC-46 can realistically carry with 10 Tonnes of freight. I do recall though that, at one point, the extra capacity offered by the MRTT was rather appealing to the USAF. The complaint from the other side was that it was unfair to consider the increased capacity and that only meeting the minimum specification should count and nothing more.

2. The Air Force’s use as a key discriminator that Northrop Grumman proposed to exceed a key performance parameter objective relating to aerial refueling to a greater degree than Boeing violated the solicitation’s evaluation provision that “no consideration will be provided for exceeding [key performance parameter] objectives.”

[LowObservable]

Ken - Your guys won. And you can say what you want about the various capabilities of the KC-46, but presumably both NG-EADS and EADS offered a compliant solution (with or without an upper deck cargo floor - as far as I can tell, the A330 as offered had a cargo door for casevac, but met the pallet requirement in the underfloor) including provision for the cloaking device, defensive laser, atomic trebuchet or whatevs.

Had it not been a compliant solution, it would have been rejected as such before the bids were in, and the AF would have found itself in a one-bid situation again, which didn't turn out too well the first time around. So as a US taxpayer, EADS did you a hell of a good turn by returning to the fight after the spec was "clarified" the first time around.

[melmothtw]

Also worth noting that the Koreans, which have no industrial drum to beat, selected the A330 MRTT over the KC-46A. When it made its selection in 2015, DAPA noted it had largely chosen the MRTT because of its superior performance - specifically endurance, fuel capacity, personnel and cargo capacity were all cited.
And I imagine if any nation is going to be flying their tankers 'close to the fight' it will be South Korea.
Go figure.

[KenV]

Originally Posted by LowObservable

Ken - Your guys won. And you can say what you want about the various capabilities of the KC-46, but presumably both NG-EADS and EADS offered a compliant solution (with or without an upper deck cargo floor - as far as I can tell, the A330 as offered had a cargo door for casevac, but met the pallet requirement in the underfloor) including provision for the cloaking device, defensive laser, atomic trebuchet or whatevs.

Ummmm, no. There was a vast difference in the first RFP and the final RFP. The first RFP was effectively an outgrowth of the tanker lease idea and consequently solicited nearly off-the-shelf tankers. NG-EADS offered a significantly larger tanker, basically a two-engine KC-10, and won. Sadly USAF had not shaken off all their procurement hanky panky that had marred previous procurements. (for example, among other things, the solicitation clearly stated that "no consideration will be provided for exceeding key performance parameter objectives." So by the established rules, offering a tanker larger than the requirements (a form of gold plating) may not influence the procurement decision.) This, among other things, resulted in Boeing challenging the decision and the government regulators (not politicians and not USAF personnel) overturned the decision and required a do over. Note that they did not decide that Boeing had won. The regulators only adjudicated that the procurement process had been violated and required a do over. There were then some false starts and other anomalies, but in the final RFP the tanking requirements stayed essentially the same (there were 372 specific tanking performance requirements in the first RFP and 379 in the final RFP. Those additional requirements all related to boom envelope, which is why Boeing switched from the KC-135 boom to the KC-10 boom.) But USAF added many new non-tanking related requirements, among them medical evacuation requirements, outsize cargo requirements, aggressive survivability enhancements and many connectivity/electronic support requirements, many classified. It was during the process of USAF adding requirements that NG pulled out. And despite all these additional requirements the delivery schedule remained very aggressive, similar to an off the shelf procurement rather than a developmental procurement. And as in the first RFP, the evaluation criteria for the final RFP could give no consideration for exceeding any requirements. Both offerings were technically acceptable in that they met all key performance parameters, but Boeing's was cheaper. Airbus's superior performance did not count and Boeing won on price.

[Trumpet trousers]

Jee-sus H Christ!!!..... when will this pointless p*ssing contest end?

pass gas

..... seems to be a lot of that going on here....
Give it a break, ffs...

[Mil-26Man]

As an side, there's an interesting aspect to the respective capabilities of both platforms in this Flight Global report from 2010, with Boeing criticizing the 'envelope protection system' of the A330 compared to the 'complete, full access to the aircraft envelope' of its KC-46A. I'm guessing the crew and passengers of ZZ333 were very happy for the protection system in February 2014...

https://www.flightglobal.com/news/ar...ensive-345235/

[KenV]

Originally Posted by Just This Once...

I've no idea who does your math(s) but trying to play top-trumps with fuel/range/payload when you are holding the KC-46 card seems rather odd.

Ummm, no you misunderstood me. I questioned the claim made by someone that the A330-300 had no centerwing tank because multiple sources indicate that -200 and -300 have the same fuel capacity. I then tried (and clearly failed) to show how "fuel uplift" is a meaningless measure of merit. What matters is how much fuel can be offloaded at various distances and/or various on station times. Both the A330MRTT and KC-46 met or exceeded USAF's hundreds of fuel offload requirements (372 to be precise.) The A330 exceeded more of those requirements than KC-46 and by a wider margin than KC-46. But KC-46 came in much cheaper, and once all the requirements had been met, it was cost that won the day, not performance.

For example, the A330 is clearly "far superior" to the 737 in range and payload, with the Airbus able to carry many more passengers much further than the Boeing airplane. But economy carriers are very focussed on price and thus buy 737 or it's Airbus equivalent A320. They neither want nor need the additional performance. But the major carriers want and need more performance, and buy the big airplane.

Perhaps comparing freighters rather than airliners is a more proper comparison. 767 freighter is clearly smaller and has "less performance" than A330 freighter. Yet over 300 767 freighters have been ordered vs 42 for the A330. Clearly, some (many?) customers need/want a freighter smaller than the A330.

In the case of USAF's tanker, a large airplane was pitted against a smaller airplane, with both able to meet the performance requirements. The smaller airplane won on price.

[KenV]

Originally Posted by Mil-26Man

As an side, there's an interesting aspect to the respective capabilities of both platforms in this Flight Global report from 2010, with Boeing criticizing the 'envelope protection system' of the A330 compared to the 'complete, full access to the aircraft envelope' of its KC-46A. I'm guessing the crew and passengers of ZZ333 were very happy for the protection system in February 2014...
https://www.flightglobal.com/news/ar...ensive-345235/

You might think that the A330 zero feedback side stick controllers and zero feedback autothrottles are a good idea, but there's plenty of people who would strongly disagree. I'm not going to weigh in on that contentious argument, but I will say that if the pilots and passengers of Air France 447 had survived, they would likely be among those disagreeing with you. And regarding ZZ333 specifically, had they been flying a KC-46, there never would have been an emergency in the first place. 'nuff said.

[KenV]

Originally Posted by melmothtw

Also worth noting that the Koreans, which have no industrial drum to beat, selected the A330 MRTT over the KC-46A. When it made its selection in 2015, DAPA noted it had largely chosen the MRTT because of its superior performance - specifically endurance, fuel capacity, personnel and cargo capacity were all cited.
And I imagine if any nation is going to be flying their tankers 'close to the fight' it will be South Korea.
Go figure.

I have no idea what the Koreans' tanker requirements were. None. And I doubt anyone here does. In any event, it would appear that A330 met their requirements better. On the other hand their neighbor, Japan, with many mutual enemies went with KC-46. Different requirements result in different solutions. Go figure.

[KenV]

Originally Posted by Just This Once...

In round figures, if you fill the A330-300 till every tank is full you still have well over 10 Tonnes of freight to offer in an otherwise empty and voluminous lower cargo bay, with the pax fit still installed above.

Interesting. Earlier in this thread Beagle claimed the opposite for Voyager. Kinda goes to show you need to carefully define terms.

Another interesting point is why would an airline operating an A330-300 airliner fill the tanks completely full of gas and then haul 10 tons of cargo while leaving the passenger compartment empty? Honestly, what airline has such an operating requirement? In other words, having a capability and having a useful capability are clearly two different things. And USAF's tanking requirements were based on actual useful needs. Both the KC-46 and A330MRTT meet or exceed those requirements. 'nuff said.