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lightsaber wrote:How to beat the economics of the B789 ot A359... Impossible. Small engines are less efficient than large as there is more surface area to flow path. Due to blade tip leakage, the pressure ratio is lower. Plus, it is just more weight.
A dream, but no leasing company will touch a quad right now.
Lightsaber
Slug71 wrote:I'd rather like to see a A345 with Trent 1000 TENs.
LDRA wrote:Depending on how well GTF gear box scales up(reliability etc.), it might be more efficient to use 4 smaller GTF powerplant versus two large conventional twin spool ones
LDRA wrote:Depending on how well GTF gear box scales up(reliability etc.), it might be more efficient to use 4 smaller GTF powerplant versus two large conventional twin spool ones
c933103 wrote:Well, I don't think such a plane could match the economic of latest fresh design twins either, but I think it would be interesting to know how far such design would be behind
c933103 wrote:Well, I don't think such a plane could match the economic of latest fresh design twins either, but I think it would be interesting to know how far such design would be behind
Spacepope wrote:lightsaber wrote:How to beat the economics of the B789 ot A359... Impossible. Small engines are less efficient than large as there is more surface area to flow path. Due to blade tip leakage, the pressure ratio is lower. Plus, it is just more weight.
A dream, but no leasing company will touch a quad right now.
Lightsaber
And Airbus has switched wing tooling for the A330 line to eliminate the common A340 outboard engine pylons, so the return on investment would be problematic to say the least.
reidar76 wrote:Spacepope wrote:lightsaber wrote:How to beat the economics of the B789 ot A359... Impossible. Small engines are less efficient than large as there is more surface area to flow path. Due to blade tip leakage, the pressure ratio is lower. Plus, it is just more weight.
A dream, but no leasing company will touch a quad right now.
Lightsaber
And Airbus has switched wing tooling for the A330 line to eliminate the common A340 outboard engine pylons, so the return on investment would be problematic to say the least.
I thought that the A330 MRTT's wing had a common structure with A340-200/-300? The mounting locations and provision for fuel piping for the A340's outboard engines is used for the wing refuelling pods.
All the aircraft will be capable of being fitted with two Cobham FRL 900E Mark 32B refuelling pods, one under each wing. Some aircraft will receive a third centreline underbelly refuelling system. The A330-200 wing shares the same design structure, including the strengthened mounting points, as that of the four-engine A340 aircraft. The wing positions for mounting the air-to-air refuelling pods therefore require minimal modification.
Pacific wrote:How much less fuel would a 34,000lb GTF burn compared with the current CFM56s?
Also, how much less fuel does the A359 consume compared to the current A343?
A pipedream, but I'd love to see if the numbers even remotely stack up.
Starlionblue wrote:Pacific wrote:How much less fuel would a 34,000lb GTF burn compared with the current CFM56s?
Also, how much less fuel does the A359 consume compared to the current A343?
A pipedream, but I'd love to see if the numbers even remotely stack up.
I don't have figures off-hand for the 343 but the 359 burns about the same per hour as a 40 ton lighter 333. The difference 359 to 343 at the same weight should be in the same ballpark as 359 to 333 at the same weight. I'll make a WAG at one ton an hour or more.
Important additional factor: The 359 does M0.85 comfortably while the 343 cruises around M0.82. In other words you're burning less per hour and on top of that you're flying for a shorter time..
Bottom line: The numbers don't even remotely stack up.
And of course it's not only about fuel consumption but about maintenance cost. A quad has more engines, more pumps, more piping, etc to keep running.
BoeingVista wrote:Starlionblue wrote:Pacific wrote:How much less fuel would a 34,000lb GTF burn compared with the current CFM56s?
Also, how much less fuel does the A359 consume compared to the current A343?
A pipedream, but I'd love to see if the numbers even remotely stack up.
I don't have figures off-hand for the 343 but the 359 burns about the same per hour as a 40 ton lighter 333. The difference 359 to 343 at the same weight should be in the same ballpark as 359 to 333 at the same weight. I'll make a WAG at one ton an hour or more.
Important additional factor: The 359 does M0.85 comfortably while the 343 cruises around M0.82. In other words you're burning less per hour and on top of that you're flying for a shorter time..
Bottom line: The numbers don't even remotely stack up.
And of course it's not only about fuel consumption but about maintenance cost. A quad has more engines, more pumps, more piping, etc to keep running.
Its not going to be competeing against the A359 but the 77E. P&W was aiming for a 15% advantage from V2500 which was within +-1% of the CFM56 so the engines should make a significant improvement in economics.
Starlionblue wrote:
77E is the 777-200ER, right? Sure, if you're talking re-engine of the 343, but the 777-200ER is 20 years old. It is not very competitive at this point, and airlines might be better served with a new 787-9 or 350-900 or perhaps even a 330neo.
BoeingVista wrote:Starlionblue wrote:
77E is the 777-200ER, right? Sure, if you're talking re-engine of the 343, but the 777-200ER is 20 years old. It is not very competitive at this point, and airlines might be better served with a new 787-9 or 350-900 or perhaps even a 330neo.
Ok so, let me be clear I cannot see any rational to build new A343's, none. However re-engining a frame that still has a lot of life in it may be viable as the capital cost could be $160m - $200m less than buying a new 787-9 and that is a whole shit load of a difference in capital.
Spacepope wrote:And Airbus has switched wing tooling for the A330 line to eliminate the common A340 outboard engine pylons, so the return on investment would be problematic to say the least.
BoeingVista wrote:How much would a used A340-300 cost, probably less than $20m 4x $4m for GTF engines so you would have a re-engined "refreshed" A340-300 for approx $36m, a new B789 is going to cost north of $200m.
zeke wrote:BoeingVista wrote:How much would a used A340-300 cost, probably less than $20m 4x $4m for GTF engines so you would have a re-engined "refreshed" A340-300 for approx $36m, a new B789 is going to cost north of $200m.
Prob looking at 10-15 million per GTF.
BoeingVista wrote:I came across an article that said GTF production costs were currently $12m per unit but needed to get down to $4m, cant lay my hands on it at the moment.
c933103 wrote:Another thing is that, if you're re-engining old 340 instead of acquiring new 787/350s, how much time can those reengined plane remain flying?
SCAT15F wrote:c933103 wrote:Another thing is that, if you're re-engining old 340 instead of acquiring new 787/350s, how much time can those reengined plane remain flying?
The answer to that question would be to look at the DC-8 Super 70 series... So a reasonably long time I would think.
Wacker1000 wrote:What if they made an A340-700 with six engines?