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- INFINITI329
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Widening Fuselage (hypothetical) CS500
How hard would it be for Airbus/BBD to widen a future CS500s fuselage by 17 inches to fit a 3rd seat in the rows? Taking it from a 3 X 2 to a 3 X 3 layout. What would be the pros & cons of such an undertaking? Would it good or bad performance wise? I look forward to reading everyone's theories.
Re: Widening Fuselage (hypothetical) CS500
You would be redesigning basically the entire aircraft. It would make more sense to just use the A320 and its fuselage if you wanted a 3x3 aircraft in that size range.
Re: Widening Fuselage (hypothetical) CS500
You don't just do modifications to an airliner. Even fitting something as harmless as an extra door or emergency exit is something that requires certification, testing and loads of paperwork. Widening a fuselage would amount to doing a completely new fuselage, which in turn amounts to a completely new aircraft type.
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- ExMilitaryEng
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Re: Widening Fuselage (hypothetical) CS500
Would require too much "alterations" to the rest of the aircraft to make it profitable.
In keeping the fuselage as is, the CS300 can be extended into a CS500 "light" at minimal costs, and would still complement perfectly Airbus offering. (ie shorter range but unbeatable CASM compared to A320neo and 737-8)
In keeping the fuselage as is, the CS300 can be extended into a CS500 "light" at minimal costs, and would still complement perfectly Airbus offering. (ie shorter range but unbeatable CASM compared to A320neo and 737-8)
Re: Widening Fuselage (hypothetical) CS500
That being said, there was a plan at one point for Boeing to offer the 747-500, -600, -700. It is my recollection that the -700 was a stretched version that was also WIDENED! That seems hard to believe, and would have also implied 3 aisles. I can’t begin to imagine the certification issues.
I would have guessed at that point, an entirely new fuselage would have made more sense.
SLCPilot.
I would have guessed at that point, an entirely new fuselage would have made more sense.
SLCPilot.
Re: Widening Fuselage (hypothetical) CS500
Slcpilot wrote:That being said, there was a plan at one point for Boeing to offer the 747-500, -600, -700. It is my recollection that the -700 was a stretched version that was also WIDENED! That seems hard to believe, and would have also implied 3 aisles. I can’t begin to imagine the certification issues.
I would have guessed at that point, an entirely new fuselage would have made more sense.
SLCPilot.
Re: Widening Fuselage (hypothetical) CS500
VSMUT,
Thanks for finding that! I actually searched for a while to find those images, unsuccessfully!
It’s hard to believe that widening the fuselage was actually considered. The 747 is already a compromise with the flat Section 41 areas.
Back to the C-series... in terms of cost and performance, there is no doubt that lengthening an existing fuselage is the way to go, with there obviously being a point of diminishing returns. While the MD-90, A346, and 753 are close, the C-series from a layman’s point of view, is not.
SLCPilot
Thanks for finding that! I actually searched for a while to find those images, unsuccessfully!
It’s hard to believe that widening the fuselage was actually considered. The 747 is already a compromise with the flat Section 41 areas.
Back to the C-series... in terms of cost and performance, there is no doubt that lengthening an existing fuselage is the way to go, with there obviously being a point of diminishing returns. While the MD-90, A346, and 753 are close, the C-series from a layman’s point of view, is not.
SLCPilot
Re: Widening Fuselage (hypothetical) CS500
Slcpilot wrote:It’s hard to believe that widening the fuselage was actually considered.
I think it was just a simple and dishonest attempt at deterring Airbus from doing the A380. It would have sown doubts about the viability of developing a completely new design when the competitor could "merely" widen an existing product.
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- INFINITI329
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Re: Widening Fuselage (hypothetical) CS500
Thanks for replies. I didn't think widening the fuselage would have affected its certification.
Re: Widening Fuselage (hypothetical) CS500
INFINITI329 wrote:Thanks for replies. I didn't think widening the fuselage would have affected its certification.
Well think of it this way: lengthening an airframe just means adding more sections of existing design (more or less). And even that requires some degree of re-certification (Airbus must additionally certify the A321 from the A320, though it's not the entire program all over again).
WIDENING would require every single part of the fuselage to be all new. All of the structure is made in a larger circle.
Consider: neither Airbus nor Boeing, nor other manufacturers, have ever taken an existing design and widened it.
You also gain a lot of weight by widening, for only one more seat per row. That compares unfavorably to lengthening, where for every three feet added, you gain five passengers.
Re: Widening Fuselage (hypothetical) CS500
Even the wingbox would need to be changed to fit a bigger fuselage. Also the base of the tail would require changes as it meets the new fuselage.
It would pretty much be a new aircraft. Probably less than 50% commonality with the CS300.
The wings and cockpit would be the main parts that could be reused.
That is why it is easier to just stretch the length.
It would pretty much be a new aircraft. Probably less than 50% commonality with the CS300.
The wings and cockpit would be the main parts that could be reused.
That is why it is easier to just stretch the length.
Re: Widening Fuselage (hypothetical) CS500
In the early 2000's Gulfstream widened the mid-size biz jet G-100 by a foot and developed the G-150. Wasn't a terribly popular type after all that but just to point out it has been done.
Re: Widening Fuselage (hypothetical) CS500
Sure it would be possible. Still, extremely expensive and time consuming. So, if you consider it as a "effort vs income", or shorter - sort of efficiency of your spending, usually there are many more efficient ways to spend money for companies like Airbus or Boeing, or Bombardier. One example presented above (and it's probably only one, or one of few examples) proves it.
Cheers,
Adam
Cheers,
Adam
Re: Widening Fuselage (hypothetical) CS500
The external fuselage diameter of the Cseries is not that different from the 737.
737: 148 inches (3.76 m)
Cseries: 146 inches (3.71 m)
It is the internal cabin width that differs: (numbers from wiki)
737: 139 inches (3.54 m)
Cseries: 129 inches (3.28 m)
Note that the external dimensions only differs two inches, while the internal dimensions differs 10 inches. Reports say the Cseries has a very silent cabin. Maybe there is a possibility to reduce wall thickness (isolation etc.) and gain a couple of inches, like Boeing is doing on the 777 -> 77X?
737: 148 inches (3.76 m)
Cseries: 146 inches (3.71 m)
It is the internal cabin width that differs: (numbers from wiki)
737: 139 inches (3.54 m)
Cseries: 129 inches (3.28 m)
Note that the external dimensions only differs two inches, while the internal dimensions differs 10 inches. Reports say the Cseries has a very silent cabin. Maybe there is a possibility to reduce wall thickness (isolation etc.) and gain a couple of inches, like Boeing is doing on the 777 -> 77X?
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- ExMilitaryEng
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Re: Widening Fuselage (hypothetical) CS500
reidar76 wrote:Note that the external dimensions only differs two inches, while the internal dimensions differs 10 inches. Reports say the Cseries has a very silent cabin. Maybe there is a possibility to reduce wall thickness (isolation etc.) and gain a couple of inches, like Boeing is doing on the 777 -> 77X?
Please, don't tell anyone! Airlines will demand gaining those few interior inches just to be able to squeeze 6 seat rows! It would then get as awful as the B737 (well, slightly worst actually).
However, the CS300 would then become an all time CASM champion, perfect for Ryanair... or maybe some Asian ultra low costs.
Re: Widening Fuselage (hypothetical) CS500
We will definitely see the C series with 6 abreast in the future. The C series maximum cabin width of 129" is at shoulder level. The 737's maximum width is at elbow level. The A320's maximum width is at knee level. This makes a huge difference in space.
As you can see with the image below the A320 cabin is only 2.8" wider at shoulder level even though it is much wider. The 737 is 134" wide at shoulder level. The A321 is 136.8" wide at shoulder level. So 129" inch is not much narrower and because it is shorter in length a few inchs could simply be taken from the aisle width.
Let calculate seat size with a 129" wide cabin.
A narrow 15" aisle leaves 114" for seating.
Eight 1.5" armrests is 12" leaves 102".
That means the seats are 17" wide.
That is acceptable by most airlines and if used only on short 1-2 hour flights it would be acceptable by all airlines. I'm pretty sure it was intentionally design for this by Bombardier. Just like Boeing originally marketed "comfort" 8AB in the 787.
The 5 abreast in the C series is more comfortable than any premium economy widebody seat. As a result of this the CASM is worse than the 737 and A320 families.
Due to the CS300 going 6 abreast I could see that the CS500 never gets made. The whole point of the CS500 stretch was to increase seats and improve CASM creating a short range monster. The wing is clearly sized to support a heavier version. However making the CS300 6 abreast would also hit that weight limit.
That narrow 15" aisle would also slow down boarding. So you would have to keep the aircraft fairly short.
As you can see with the image below the A320 cabin is only 2.8" wider at shoulder level even though it is much wider. The 737 is 134" wide at shoulder level. The A321 is 136.8" wide at shoulder level. So 129" inch is not much narrower and because it is shorter in length a few inchs could simply be taken from the aisle width.
Let calculate seat size with a 129" wide cabin.
A narrow 15" aisle leaves 114" for seating.
Eight 1.5" armrests is 12" leaves 102".
That means the seats are 17" wide.
That is acceptable by most airlines and if used only on short 1-2 hour flights it would be acceptable by all airlines. I'm pretty sure it was intentionally design for this by Bombardier. Just like Boeing originally marketed "comfort" 8AB in the 787.
The 5 abreast in the C series is more comfortable than any premium economy widebody seat. As a result of this the CASM is worse than the 737 and A320 families.
Due to the CS300 going 6 abreast I could see that the CS500 never gets made. The whole point of the CS500 stretch was to increase seats and improve CASM creating a short range monster. The wing is clearly sized to support a heavier version. However making the CS300 6 abreast would also hit that weight limit.
That narrow 15" aisle would also slow down boarding. So you would have to keep the aircraft fairly short.
Re: Widening Fuselage (hypothetical) CS500
Bombardier have even set the payload limits for 6AB.
The 133 and 160 max seating of the CS100 and CS300 would increase to 150 and 180. Give or take a couple seats.
With 100kg per passenger that means the payload would be 15,000kg and 18,000kg for the two aircraft. Wikipedia lists the payloads as 15,127kg and 18,711kg
That is a very high payload and is higher than most 737 models.
The 133 and 160 max seating of the CS100 and CS300 would increase to 150 and 180. Give or take a couple seats.
With 100kg per passenger that means the payload would be 15,000kg and 18,000kg for the two aircraft. Wikipedia lists the payloads as 15,127kg and 18,711kg
That is a very high payload and is higher than most 737 models.
Re: Widening Fuselage (hypothetical) CS500
reidar76 wrote:The external fuselage diameter of the Cseries is not that different from the 737.
737: 148 inches (3.76 m)
Cseries: 146 inches (3.71 m)
It is the internal cabin width that differs: (numbers from wiki)
737: 139 inches (3.54 m)
Cseries: 129 inches (3.28 m)
Note that the external dimensions only differs two inches, while the internal dimensions differs 10 inches. Reports say the Cseries has a very silent cabin. Maybe there is a possibility to reduce wall thickness (isolation etc.) and gain a couple of inches, like Boeing is doing on the 777 -> 77X?
While your numbers are not wrong per se, you've taken the width of the 737 fuselage and compared it to the height of the cseries. The width is 3.50m. So fuselage walls have indeed identical width.
Re: Widening Fuselage (hypothetical) CS500
mat66 wrote:While your numbers are not wrong per se, you've taken the width of the 737 fuselage and compared it to the height of the cseries. The width is 3.50m. So fuselage walls have indeed identical width.
Oops
≠ "fuselage diameter"
But even with no widening of the cabin, a cabin width of 129 inches (3.28 m) should be sufficient for a 6 abreast on a short haul flight. The Cseries at 6 abreast would have the same seat and aisle width as on an A350 at 10 abreast (like those that fly for Air Caraibes and French Blue).
Re: Widening Fuselage (hypothetical) CS500
reidar76 wrote:mat66 wrote:While your numbers are not wrong per se, you've taken the width of the 737 fuselage and compared it to the height of the cseries. The width is 3.50m. So fuselage walls have indeed identical width.
Oops
≠ "fuselage diameter"
But even with no widening of the cabin, a cabin width of 129 inches (3.28 m) should be sufficient for a 6 abreast on a short haul flight. The Cseries at 6 abreast would have the same seat and aisle width as on an A350 at 10 abreast (like those that fly for Air Caraibes and French Blue).
I would not put it past the airlines to do it, but it would be very tight. The narrowest 6 abreast single aisle is the BAe 146. According to wikipedia cabin width is 3.42m. I've been on it once and it is tight.
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