aerolimani wrote:

BrianDromey wrote:

I think posters are looking at this the wrong way round. It’s not that the A32x can’t be re-winged, the real question is what a new wing is bolted to.
What aero, construction and weight advantages can a new carbon panel/barrel construction fuselage bring Vs bolting a new wing/tailplane/engine to the current structure. How does this impact the weight/fuel burn/payload? Most importantly, what are Boeing doing?

If an A320 based A321XLRnneo or “A322” can be competitive with a “797” it would be a lot cheaper and quicker to develop - apparently some work is already done if rumours are to be believed.

The consensus seems to be that CFRP fuselages are beneficial for widebody fuselages, but of less benefit to smaller aircraft. Bombardier considered it for the CSeries, but ultimately went for Al–Li instead. Part of the argument against CFRP is the greater risk of damage from ground vehicles that a NB experiences versus a WB; more frequent loading/unloading (with pressure for quick turnarounds), and being closer to the ground.

To make matters worse, there is not that much improvement in weight between regular aluminum alloys and Al-Li; around 5% lighter, I think. Over a fuselage as small as an A320 family aircraft, this is not a significant number.

As to weight savings in the structure, the A320 already contains many parts made from AFRP, GFRP, and CFRP.

I feel like we're in a waiting game right now. With current technology/materials/engineering, it doesn't seem like there is much to be done to improve the current A320 where the benefit outweighs the cost. We're waiting for technologies like laminar flow to mature. For now, I don't see a rewing (or a new fuselage) coming for the A320 family.

I used to imagine an A322 with a new wing… and as a response to a future Boeing, this kind of things could possibly happen. But, for now, it's not needed, and the cost does not justify the benefit.

Good points. We've been in a waiting game since 1988.

aerolimani wrote:

I used to imagine an A322 with a new wing… and as a response to a future Boeing, this kind of things could possibly happen. But, for now, it's not needed, and the cost does not justify the benefit.

Well, cost-benefit analysis will play a big part in determining whether a new wing design will go ahead. With a huge backlog of orders, Airbus has little incentive to do so. The key driver will be what Boeing will does. Airbus needs to remain competitive. So this new wing decision can wait till the competitive environment changes.

brindabella wrote:

kitplane01 wrote:

brindabella wrote:

The huge (and increasing) pressure on both AB and BA to increase and increase and increase their NB production rates has 3 consequences:

2) it will get even harder for EITHER AB or BA to break away and go to another generation. The other party will immediately swoop in, take (basically) all of the (MASSIVE) market and feast on the profits. The OEM which breaks ranks will face years of pain b4 it can get it's new product out - to be faced by the other which immediately discounts massively (which will be very very easy and basically painless).

I don't think this is true. Airbus was able to transition from the A320 to the A320neo without any pause in production. Same for A330 -> A330neo. Same for the 777->777X. Same for the 737->737MAX.

So I'm quite sure Airbus could go from a 320-oldwing to 320-newwing without a production pause.

Not the transition difficulties - at least technically.

But rather trying to manage your own customer-base when each customer decides at the same moment that they have fallen out of love with the NB as already ordered and now wants the wonderful new whizz-bang. Desperately.
Additionally, meantime you have ramped-up to 70 or more frames a Month and have ironclad contracts with a constellation of parts-suppliers to take ALL their contracted products at a high rate for years and years to come … or else.
And to keep a steady (but steadily reducing) flow of orders for the existing frame, you find yourself having to go very cheap. (777W, EG).

Let's say for argument's sake it was BA which, some time in the future, is contemplating the big jump.One solution would be to offer the NSA/whatever at relatively high prices to discourage the existing customers from rushing out of the current MAX queue and onto the NSA queue ...

cheers

I still don't understand. Airbus just did the transition from the A320 -> A320neo, and kept production rate up despite the preference by customers for the NEO over the CEO, and the need to change some supplier built parts. Would not the same techniques solve the same problem when switching from the A320oldwing -> A320newwing?

I really think Airbus could manage this.

Boeing thinks they can manage the 777 -> 777X transition too.

Hard to know if re-winging is worth it until you know what performance/weight improvements might be possible. What changes or new technologies one could put into a hypothetical new wing for the A320? And how much improvement might one see?

Carbon fibre structure
Folding wingtips
Drooping ailerons (does an A320 already have this?)
Load alleviation for a lighter structure
Better airfoil shape (aren't they at a practical max for this?)
Double slotted flaps
Blown flaps (this seems a real stretch)
Trailing edge flaps along almost the whole trailing edge .. roll control by spoiler
Remounting the engine for better aero to adjust for the increase in fan diameter


Anyone

1989worstyear wrote:

we’ve been in a waiting game since 1988.

Did engine innovation also stop in 1988? What about navigation systems?

kitplane01 wrote:

Hard to know if re-winging is worth it until you know what performance/weight improvements might be possible. What changes or new technologies one could put into a hypothetical new wing for the A320? And how much improvement might one see?

Carbon fibre structure
Folding wingtips
Drooping ailerons (does an A320 already have this?)
Load alleviation for a lighter structure
Better airfoil shape (aren't they at a practical max for this?)
Double slotted flaps
Blown flaps (this seems a real stretch)
Trailing edge flaps along almost the whole trailing edge .. roll control by spoiler
Remounting the engine for better aero to adjust for the increase in fan diameter


Anyone

Drooped spoilers and variable camber may be improvement opportunities

mjoelnir wrote:

The A300 wing was already a supercritcal wing and very advanced. I think we can not go just by years of production. I would for example not agree that the 737NG wing is more advanced than the A320 wing. Airbus has a slightly smaller wing, with simpler design of the high lift devices, that is as or more effective than the slightly bigger wing on the 737NG.

Don’t forget the 737NG wing flies higher than the A320. It is hard to say what more advanced means just like it is hard to say what the first supercritical wing is since the designs have been evolving and improving aerodynamically

Newbiepilot wrote:

1989worstyear wrote:

we’ve been in a waiting game since 1988.

Did engine innovation also stop in 1988? What about navigation systems?

kitplane01 wrote:

Hard to know if re-winging is worth it until you know what performance/weight improvements might be possible. What changes or new technologies one could put into a hypothetical new wing for the A320? And how much improvement might one see?

Carbon fibre structure
Folding wingtips
Drooping ailerons (does an A320 already have this?)
Load alleviation for a lighter structure
Better airfoil shape (aren't they at a practical max for this?)
Double slotted flaps
Blown flaps (this seems a real stretch)
Trailing edge flaps along almost the whole trailing edge .. roll control by spoiler
Remounting the engine for better aero to adjust for the increase in fan diameter


Anyone

Drooped spoilers and variable camber may be improvement opportunities

mjoelnir wrote:

The A300 wing was already a supercritcal wing and very advanced. I think we can not go just by years of production. I would for example not agree that the 737NG wing is more advanced than the A320 wing. Airbus has a slightly smaller wing, with simpler design of the high lift devices, that is as or more effective than the slightly bigger wing on the 737NG.

Don’t forget the 737NG wing flies higher than the A320. It is hard to say what more advanced means just like it is hard to say what the first supercritical wing is since the designs have been evolving and improving aerodynamically

Well, it did take 27 years for the A320 to find an alternative to the CFM56-5 and V2500, and GPS was around at the start of the 90s

GalebG4 wrote:

With not so successful a380 project, a330 not selling well and a220 as new family member I personally don’t think Airbus probably won’t do anything i post in this topic. Since Ryanair showed us that one type makes a lot of economic sense, it would be nice if all airbus a320 family members have it’s own carbon wing so all of the versions are most efficient in its own sector.
A317neo as counterpart to e190, A318neo, A319neo, A320neo, a321neo and a322neo.
Same type of the aircraft with 7 different wings and one type of motor that can fit all the versions.
This idea probably doesn’t make economic sense but since e175 showed us that different versions of wings makes sense, it seems that airbus went in wrong direction. What do you think airbus could do with a320 family?

Why do you think they took over the C-Series?

I've seen this topic quite a few times and the same conclusions keep coming up. I'll list them below.

1) The A321NEO ideally needs a greater span wing to improve fuel efficiency but the downside is greater airport costs due to it being code D.

2) On short trips airport fees become a larger percentage of total cost. On a 500nm flight the newer larger wing might have a higher total trip cost with the fuel savings entirely eaten up by extra airport gate fees.

3) Most agree Airbus ideally needs two wing sizes. Code C short range wing and a code D long range wing. They could keep the current wing to do the job of the small wing and introduce a new wing for the long range models.

4) Most members have suggested something along the line of the following. Two wings sizes and 3-4 fuselage lengths. The stretched small wing model often gets called the A320.5

5) Currently we have two models with 99% of the sales.
A320 37.5m long at 79T
A321 44.5m long at 97T.

What you'd want is:
37.5m long at 80T 4000nm small wing
41.5m long at 80T 3000nm small wing
44.5m long at 100T 5000nm big wing
48.5m long at 100T 4000nm big wing
The best bit is the big wing has a better lift to drag ratio so it can retain the same engine type of the smaller wing models.

6) Some members suggest the A220-500 stretch could fill the role of the small wing A320 model allowing Airbus to concentrate on the big wing A321/A322 models.

Newbiepilot wrote:

WIederling wrote:

1989worstyear wrote:

In other words - we've peaked 30 years ago...

Innovation rate has peaked. Not advance and maturity.

If you look at supercritical wing design ( whatever name you use )
the theoretical background was done in the 40ties.

The 50/60ties saw its communicated reinvention in the US.
you still see detail advances but they are small, incremental not large step changes.

Things will change with the advent of real laminar flow designs. That could? will be
the next s-curve in advances.

Are you implying that the a320 wing has thesame supercritical elements found on the a350?

This 1988 innovation peak is silly nonsense.

You are not good at reading comprehension.
I wrote "rate of innovation" peak.

Afaics the profile differences over the airbus family are minor. What changed for example is reducing tailplane drag ( from inverted lift ) by way of moving CoG ( trim tank ) to changing camber for moving CoL. Another change line is High Lift arrangements
going to drop nose devices and simpler trailing edge "things".
Also aerodynamically improved surfaces and quite a bit of effort spent on improving fairings.
Lastly complex wingtip devices seem to have brought quite a bit of progress.

WIederling wrote:

Newbiepilot wrote:

WIederling wrote:

Innovation rate has peaked. Not advance and maturity.

If you look at supercritical wing design ( whatever name you use )
the theoretical background was done in the 40ties.

The 50/60ties saw its communicated reinvention in the US.
you still see detail advances but they are small, incremental not large step changes.

Things will change with the advent of real laminar flow designs. That could? will be
the next s-curve in advances.

Are you implying that the a320 wing has thesame supercritical elements found on the a350?

This 1988 innovation peak is silly nonsense.

You are not good at reading comprehension.
I wrote "rate of innovation" peak.

Afaics the profile differences over the airbus family are minor. What changed for example is reducing tailplane drag ( from inverted lift ) by way of moving CoG ( trim tank ) to changing camber for moving CoL. Another change line is High Lift arrangements
going to drop nose devices and simpler trailing edge "things".
Also aerodynamically improved surfaces and quite a bit of effort spent on improving fairings.
Lastly complex wingtip devices seem to have brought quite a bit of progress.

I find reading your posts to be quite difficult due to the poor grammar and unusual syntax. I assume that is due to language barrier and translating from German, but no issues with that. This is an international forum and Europeans are well represented.

Airbus is quite good at engineering reuse.

Newbiepilot wrote:

WIederling wrote:

Newbiepilot wrote:

Are you implying that the a320 wing has thesame supercritical elements found on the a350?

This 1988 innovation peak is silly nonsense.

You are not good at reading comprehension.
I wrote "rate of innovation" peak.

Afaics the profile differences over the airbus family are minor. What changed for example is reducing tailplane drag ( from inverted lift ) by way of moving CoG ( trim tank ) to changing camber for moving CoL. Another change line is High Lift arrangements
going to drop nose devices and simpler trailing edge "things".
Also aerodynamically improved surfaces and quite a bit of effort spent on improving fairings.
Lastly complex wingtip devices seem to have brought quite a bit of progress.

I find reading your posts to be quite difficult due to the poor grammar and unusual syntax. I assume that is due to language barrier and translating from German, but no issues with that. This is an international forum and Europeans are well represented.

Airbus is quite good at engineering reuse.

That is one of their primary aim of design, having all families that similar, that you can move items, designed for the newest family or model, over to other families or models. The recent upgrades, especially regarding the flight controls/computers in the A320 and A330 families, are based on moving features designed for the A380 and A350 down the line.
We also see new stuff tested on the A320 test frame, that are likely to appear in different families in the next years.

I don't think a new wing on an A320 will give him a big advantage
Most of A320s routes are about 3 hours of flight in Europe, maybe more in the US
But two new engines are good enough for now
Maybe the A321LR can take advantage of a new wing on longer routes?
BLADE A340 is making a lot of flight hours anyway

Didn't airbus test fly an A320 with a 'more electric' wing in 2015 and with the use of electro-hydraulic actuators enable the reduction of a whole hydraulic system? maybe this could pave the way for a new wing and maybe even just to reduce the current wing weight or even allow more space for fuel tank integration?

Fred

flipdewaf wrote:

Didn't airbus test fly an A320 with a 'more electric' wing in 2015 and with the use of electro-hydraulic actuators enable the reduction of a whole hydraulic system? maybe this could pave the way for a new wing and maybe even just to reduce the current wing weight or even allow more space for fuel tank integration?

They've test flown a range of more electric thingies.
Would it make sense to morph the A320 into a 2H2E architecture?

FatCat wrote:

BLADE A340 is making a lot of flight hours anyway

do we know anything about how laminar flow ( like the BLADE demonstrator )
will effect wing loading?

WIederling wrote:

FatCat wrote:

BLADE A340 is making a lot of flight hours anyway

do we know anything about how laminar flow ( like the BLADE demonstrator )
will effect wing loading?

some will answer you that "a real quick google search will answer this question", a.net in a nutshell
but I try to give you a better answer,
that reading articles about the BLADE concept no difference in wing loads are mentioned, but in speed and materials, with various wing's weight and laminar flow advantages, ending in lower emissions and fuel savings and so on.
go check http://www.cleansky.eu/ the web site is made quite well

FatCat wrote:

WIederling wrote:

FatCat wrote:

BLADE A340 is making a lot of flight hours anyway

do we know anything about how laminar flow ( like the BLADE demonstrator )
will effect wing loading?

some will answer you that "a real quick google search will answer this question", a.net in a nutshell
but I try to give you a better answer,
that reading articles about the BLADE concept no difference in wing loads are mentioned, but in speed and materials, with various wing's weight and laminar flow advantages, ending in lower emissions and fuel savings and so on.
go check http://www.cleansky.eu/ the web site is made quite well

Thank you.

the question is will I need more or less wing area for the same lifting capabilities.

lower emissions from a less draggy laminar flow wing is an intrinsic advantage.

FatCat wrote:

I don't think a new wing on an A320 will give him a big advantage
Most of A320s routes are about 3 hours of flight in Europe, maybe more in the US
But two new engines are good enough for now
Maybe the A321LR can take advantage of a new wing on longer routes?
BLADE A340 is making a lot of flight hours anyway

Very important point. The average A320 flight is just over 2 hours. While these higher weight versions with more range and fuel tanks get all the attention, most airlines want cheap and efficient over 500-1500 miles where most of their flights are.

Airbus wants to upsell Airlines to the larger A321 and higher weight versions since these are more expensive and more profitable for Airbus to sell. All this talk of A321XLRs is what Airbus marketing wants to promote even though the majority of orders are for the standard A320neo.

DL717 wrote:

GalebG4 wrote:

With not so successful a380 project, a330 not selling well and a220 as new family member I personally don’t think Airbus probably won’t do anything i post in this topic. Since Ryanair showed us that one type makes a lot of economic sense, it would be nice if all airbus a320 family members have it’s own carbon wing so all of the versions are most efficient in its own sector.
A317neo as counterpart to e190, A318neo, A319neo, A320neo, a321neo and a322neo.
Same type of the aircraft with 7 different wings and one type of motor that can fit all the versions.
This idea probably doesn’t make economic sense but since e175 showed us that different versions of wings makes sense, it seems that airbus went in wrong direction. What do you think airbus could do with a320 family?

Why do you think they took over the C-Series?

Just because of 135-160 seat sector of aircraft, but they can’t shrink a220 as counterpart to e175 or e190. If they want to enter that market then they need smaller wing, so it doesn’t make sense. They can and they probably will make a220-500 190 seats version, but a220 is not part of this topic.

musman9853 wrote:

GalebG4 wrote:

Biggest question with airbus family is what makes economic sense?
A320xlr would be nice to see but probably would not make sense, stretched version of a320neo, a320,5 neo xlr with 200 seats would probably make more sense for ulcc players, since Boeing is making NMA. Nobody really knows what is NMA going to be, but shortened version can be 737 max 8 replacement so airbus must be cautious not to make same mistake as it did with a330 and 787. YOU MUST BE IDIOT NOT TO THINK THAT BOEING IS GOING TO MAKE SAME TYPE OF THE AIRCRAFT FOR 60 YEARS, NMA MUST BE REPLACEMENT in 2027-2030.

the nma specs have been all but confirmed. the nma-6 will have 225 seats and fly 5k nm, and the nma-7 will seat 265 and fly 4.5k nm.

It’s all about surprise, if you are unpredictable then other counterpart Airbus will probably lose precious time while you in this case Boeing will try as hard as possible make airbus made same mistake as they did with a340 family. It is harder to Airbus to make good decision then with Boeing which will make as best as product as it can be.

GalebG4 wrote:

musman9853 wrote:

GalebG4 wrote:

Biggest question with airbus family is what makes economic sense?
A320xlr would be nice to see but probably would not make sense, stretched version of a320neo, a320,5 neo xlr with 200 seats would probably make more sense for ulcc players, since Boeing is making NMA. Nobody really knows what is NMA going to be, but shortened version can be 737 max 8 replacement so airbus must be cautious not to make same mistake as it did with a330 and 787. YOU MUST BE IDIOT NOT TO THINK THAT BOEING IS GOING TO MAKE SAME TYPE OF THE AIRCRAFT FOR 60 YEARS, NMA MUST BE REPLACEMENT in 2027-2030.

the nma specs have been all but confirmed. the nma-6 will have 225 seats and fly 5k nm, and the nma-7 will seat 265 and fly 4.5k nm.

It’s all about surprise, if you are unpredictable then other counterpart Airbus will probably lose precious time while you in this case Boeing will try as hard as possible make airbus made same mistake as they did with a340 family. It is harder to Airbus to make good decision then with Boeing which will make as best as product as it can be.

that was true a year ago before the specs were finalized. all indications are that those specs have been finalized

musman9853 wrote:

GalebG4 wrote:

musman9853 wrote:

the nma specs have been all but confirmed. the nma-6 will have 225 seats and fly 5k nm, and the nma-7 will seat 265 and fly 4.5k nm.

It’s all about surprise, if you are unpredictable then other counterpart Airbus will probably lose precious time while you in this case Boeing will try as hard as possible make airbus made same mistake as they did with a340 family. It is harder to Airbus to make good decision then with Boeing which will make as best as product as it can be.

that was true a year ago before the specs were finalized. all indications are that those specs have been finalized

Boeing has pulled rabbit two times 777 and 787.

So I ran a model of a re-winged A321.
Aircraft Changes:
Wing area increased to 156m^2
Wing sweep to 30
Span to 42m
MTOW 105000kg
MZFW - 80000kg
Empty weight weight increase ~2.5t
Available wing tankage ~ 31M^3 (26t)

Mission:
Still air distance 5000nm
Speed 0.8M
DOW - 54000kg
Payload - 20600kg (206pax)
Landing weight - 76920kg
Takeoff weight - 102347kg
Fuel Used = 24675kg
Time taken = 11:07.

Fred

Newbiepilot wrote:

FatCat wrote:

I don't think a new wing on an A320 will give him a big advantage
Most of A320s routes are about 3 hours of flight in Europe, maybe more in the US
But two new engines are good enough for now
Maybe the A321LR can take advantage of a new wing on longer routes?
BLADE A340 is making a lot of flight hours anyway

Very important point. The average A320 flight is just over 2 hours. While these higher weight versions with more range and fuel tanks get all the attention, most airlines want cheap and efficient over 500-1500 miles where most of their flights are.

Airbus wants to upsell Airlines to the larger A321 and higher weight versions since these are more expensive and more profitable for Airbus to sell. All this talk of A321XLRs is what Airbus marketing wants to promote even though the majority of orders are for the standard A320neo.

Amusing.
"The average A320 flight is just over 2 hours."
Tells you nothing about distribution nor about demand.


It has been repeated here ad nauseam.
Airlines procurement people are professionals.
They don't go and buy a Jugo just because it is Lexus branded.

GalebG4 wrote:

musman9853 wrote:

GalebG4 wrote:

It’s all about surprise, if you are unpredictable then other counterpart Airbus will probably lose precious time while you in this case Boeing will try as hard as possible make airbus made same mistake as they did with a340 family. It is harder to Airbus to make good decision then with Boeing which will make as best as product as it can be.

that was true a year ago before the specs were finalized. all indications are that those specs have been finalized

Boeing has pulled rabbit two times 777 and 787.

i'm not sure i follow.

flipdewaf wrote:

So I ran a model of a re-winged A321.
Aircraft Changes:
Wing area increased to 156m^2
Wing sweep to 30
Span to 42m
MTOW 105000kg
MZFW - 80000kg
Empty weight weight increase ~2.5t
Available wing tankage ~ 31M^3 (26t)

Mission:
Still air distance 5000nm
Speed 0.8M
DOW - 54000kg
Payload - 20600kg (206pax)
Landing weight - 76920kg
Takeoff weight - 102347kg
Fuel Used = 24675kg
Time taken = 11:07.

Fred

is that including a folding wingtip? still, nice work!

musman9853 wrote:

flipdewaf wrote:

So I ran a model of a re-winged A321.
Aircraft Changes:
Wing area increased to 156m^2
Wing sweep to 30
Span to 42m
MTOW 105000kg
MZFW - 80000kg
Empty weight weight increase ~2.5t
Available wing tankage ~ 31M^3 (26t)

Mission:
Still air distance 5000nm
Speed 0.8M
DOW - 54000kg
Payload - 20600kg (206pax)
Landing weight - 76920kg
Takeoff weight - 102347kg
Fuel Used = 24675kg
Time taken = 11:07.

Fred

is that including a folding wingtip? still, nice work!

No Additional weight included for a folding wing tip mechanism but for the aero geometry it is basically a bigger and higher AR wing. I would be making a wild guess if I was to say how much the folding mechanism would weigh but we could make some assumptions based on the 777X numbers I suppose if anyone has them to hand.

Edit: according to my models (similar principle to how ferpe (of leeham fame) built a comparison method but with a bit more mission profiling going on such as adding diversion distances and step climbing and climb to initial cruise being factored in) the rewinged A320 that I gave numbers for has a crossover point with the standard NEO on flights over ~1100nm.

Fred

flipdewaf wrote:

So I ran a model of a re-winged A321.
Aircraft Changes:
Wing area increased to 156m^2
Wing sweep to 30
Span to 42m
MTOW 105000kg
MZFW - 80000kg
Empty weight weight increase ~2.5t
Available wing tankage ~ 31M^3 (26t)

Mission:
Still air distance 5000nm
Speed 0.8M
DOW - 54000kg
Payload - 20600kg (206pax)
Landing weight - 76920kg
Takeoff weight - 102347kg
Fuel Used = 24675kg
Time taken = 11:07.

Fred

What kind of penalties would there be for further increasing the optimal cruise speed to say .82 and vmo to say .85?

impilot wrote:

flipdewaf wrote:

So I ran a model of a re-winged A321.
Aircraft Changes:
Wing area increased to 156m^2
Wing sweep to 30
Span to 42m
MTOW 105000kg
MZFW - 80000kg
Empty weight weight increase ~2.5t
Available wing tankage ~ 31M^3 (26t)

Mission:
Still air distance 5000nm
Speed 0.8M
DOW - 54000kg
Payload - 20600kg (206pax)
Landing weight - 76920kg
Takeoff weight - 102347kg
Fuel Used = 24675kg
Time taken = 11:07.

Fred

What kind of penalties would there be for further increasing the optimal cruise speed to say .82 and vmo to say .85?

I countered the change from 0.78M to 0.8M by altering wing sweep to 30°. I would imagine that if you were trying to get to 0.85 then you would need a bit more of a sweep and a thinner wing from ~0.12 to 0.1. this would impact the weight but changes to the drag at that level will be lost in the noise and uncertainty of the models. I'll have a go though.

Fred

Deleted...and meant mmo not vmo. Thanks.

Newbiepilot wrote:

Don’t forget the 737NG wing flies higher than the A320. It is hard to say what more advanced means just like it is hard to say what the first supercritical wing is since the designs have been evolving and improving aerodynamically

Taking your observation "737NG wing flies higher than the A320" on face value
would create an even stronger indicator that
the A320 wing is superior to the NG "shows signs of supercritial design" wing.( cite NASA)

i.e. having to fly in a denser more draggy environment and still showing an advantage over longer distances.

WIederling wrote:

Newbiepilot wrote:

Don’t forget the 737NG wing flies higher than the A320. It is hard to say what more advanced means just like it is hard to say what the first supercritical wing is since the designs have been evolving and improving aerodynamically

Taking your observation "737NG wing flies higher than the A320" on face value
would create an even stronger indicator that
the A320 wing is superior to the NG "shows signs of supercritial design" wing.( cite NASA)

i.e. having to fly in a denser more draggy environment and still showing an advantage over longer distances.

The 737NG has a higher service ceiling. When designing the wing for the NG being able to fly at 41000ft was a requirement. Just one more way that the A320 and 737 are optimized for a different set of requirements

Newbiepilot wrote:

WIederling wrote:

Newbiepilot wrote:

Don’t forget the 737NG wing flies higher than the A320. It is hard to say what more advanced means just like it is hard to say what the first supercritical wing is since the designs have been evolving and improving aerodynamically

Taking your observation "737NG wing flies higher than the A320" on face value
would create an even stronger indicator that
the A320 wing is superior to the NG "shows signs of supercritial design" wing.( cite NASA)

i.e. having to fly in a denser more draggy environment and still showing an advantage over longer distances.

The 737NG has a higher service ceiling. When designing the wing for the NG being able to fly at 41000ft was a requirement. Just one more way that the A320 and 737 are optimized for a different set of requirements

Service ceiling must include a certification factor, rather than a physical limitation. The ACJ versions of the A320 family have 41.000 feet service ceiling at the same MTOW.

So I assume that you assume wrong.

mjoelnir wrote:

Newbiepilot wrote:

WIederling wrote:

Taking your observation "737NG wing flies higher than the A320" on face value
would create an even stronger indicator that
the A320 wing is superior to the NG "shows signs of supercritial design" wing.( cite NASA)

i.e. having to fly in a denser more draggy environment and still showing an advantage over longer distances.

The 737NG has a higher service ceiling. When designing the wing for the NG being able to fly at 41000ft was a requirement. Just one more way that the A320 and 737 are optimized for a different set of requirements

Service ceiling must include a certification factor, rather than a physical limitation. The ACJ versions of the A320 family have 41.000 feet service ceiling at the same MTOW.

So I assume that you assume wrong.

Having a structural maintenance program to allow the plane to fly at 41,000 in a low cycle ACJ operation isnt the same as being designed to efficiently fly at that altitude in passenger operation. My point is the airplanes are optimized around different requirements

flipdewaf wrote:

impilot wrote:

flipdewaf wrote:

So I ran a model of a re-winged A321.
Aircraft Changes:
Wing area increased to 156m^2
Wing sweep to 30
Span to 42m
MTOW 105000kg
MZFW - 80000kg
Empty weight weight increase ~2.5t
Available wing tankage ~ 31M^3 (26t)

Mission:
Still air distance 5000nm
Speed 0.8M
DOW - 54000kg
Payload - 20600kg (206pax)
Landing weight - 76920kg
Takeoff weight - 102347kg
Fuel Used = 24675kg
Time taken = 11:07.

Fred

What kind of penalties would there be for further increasing the optimal cruise speed to say .82 and vmo to say .85?

I countered the change from 0.78M to 0.8M by altering wing sweep to 30°. I would imagine that if you were trying to get to 0.85 then you would need a bit more of a sweep and a thinner wing from ~0.12 to 0.1. this would impact the weight but changes to the drag at that level will be lost in the noise and uncertainty of the models. I'll have a go though.

Fred

Aircraft Changes:
Wing area increased to 156m^2
Wing sweep to 30
Span to 42m
Wig T/C from 0.12 to 0.1
MTOW 105000kg
MZFW - 80000kg
Empty weight weight increase ~4t
Available wing tankage ~ 26M^3 (22t)

Mission:
Still air distance 5000nm
Speed 0.85M
DOW - 55500kg
Payload - 20600kg (206pax)
Landing weight - 80187kg
Takeoff weight - 104643kg
Fuel Used = 24455kg
Time taken = 10:30.

Notes:
-Aircraft empty weight goes up
-Aircraft landing weight goes up
-Aircraft takeoff weight goes up
Fuel used goes down (very slightly)
-Flight time reduces
-Fuel Volume Drops (critically) although we know there is space for an ACT.

Although it looks promising because less fuel is used the previous example would actually have more range available and would perform with lower fuel burns than this variant at the shorter ranges dues to the lower (~3%) empty weight. Swings and roundabouts.

Fred

mjoelnir wrote:

Newbiepilot wrote:

WIederling wrote:

Taking your observation "737NG wing flies higher than the A320" on face value
would create an even stronger indicator that
the A320 wing is superior to the NG "shows signs of supercritial design" wing.( cite NASA)

i.e. having to fly in a denser more draggy environment and still showing an advantage over longer distances.

The 737NG has a higher service ceiling. When designing the wing for the NG being able to fly at 41000ft was a requirement. Just one more way that the A320 and 737 are optimized for a different set of requirements

Service ceiling must include a certification factor, rather than a physical limitation. The ACJ versions of the A320 family have 41.000 feet service ceiling at the same MTOW.

So I assume that you assume wrong.

What does "Service ceiling must include a certification factor," mean? What certification factor are you talking about?

flipdewaf wrote:

flipdewaf wrote:

impilot wrote:

What kind of penalties would there be for further increasing the optimal cruise speed to say .82 and vmo to say .85?

I countered the change from 0.78M to 0.8M by altering wing sweep to 30°. I would imagine that if you were trying to get to 0.85 then you would need a bit more of a sweep and a thinner wing from ~0.12 to 0.1. this would impact the weight but changes to the drag at that level will be lost in the noise and uncertainty of the models. I'll have a go though.

Fred

Aircraft Changes:
Wing area increased to 156m^2
Wing sweep to 30
Span to 42m
Wig T/C from 0.12 to 0.1
MTOW 105000kg
MZFW - 80000kg
Empty weight weight increase ~4t
Available wing tankage ~ 26M^3 (22t)

Mission:
Still air distance 5000nm
Speed 0.85M
DOW - 55500kg
Payload - 20600kg (206pax)
Landing weight - 80187kg
Takeoff weight - 104643kg
Fuel Used = 24455kg
Time taken = 10:30.

Notes:
-Aircraft empty weight goes up
-Aircraft landing weight goes up
-Aircraft takeoff weight goes up
Fuel used goes down (very slightly)
-Flight time reduces
-Fuel Volume Drops (critically) although we know there is space for an ACT.

Although it looks promising because less fuel is used the previous example would actually have more range available and would perform with lower fuel burns than this variant at the shorter ranges dues to the lower (~3%) empty weight. Swings and roundabouts.

Fred

If the MTOW goes from 97 tonnes to 105 tonnes, are you also increasing engine thrust?
Any data on runway required?

Love this kind of thing

kitplane01 wrote:

mjoelnir wrote:

Newbiepilot wrote:

The 737NG has a higher service ceiling. When designing the wing for the NG being able to fly at 41000ft was a requirement. Just one more way that the A320 and 737 are optimized for a different set of requirements

Service ceiling must include a certification factor, rather than a physical limitation. The ACJ versions of the A320 family have 41.000 feet service ceiling at the same MTOW.

So I assume that you assume wrong.

What does "Service ceiling must include a certification factor," mean? What certification factor are you talking about?

Because the service ceiling does change with the different use. So it is not a physical limitation, but a certified limitation.

mjoelnir wrote:

kitplane01 wrote:

mjoelnir wrote:

Service ceiling must include a certification factor, rather than a physical limitation. The ACJ versions of the A320 family have 41.000 feet service ceiling at the same MTOW.

So I assume that you assume wrong.

What does "Service ceiling must include a certification factor," mean? What certification factor are you talking about?

Because the service ceiling does change with the different use. So it is not a physical limitation, but a certified limitation.

True. An A320 can probably climb to 45000ft under the right conditions. However optimized for efficiency is different from capability. The 737NG wing was designed to cruise at 410 in normal operation. The A320 wasnt. This is an example of different requiremengs and constraints which can explain why the 737 performs differently.

You still have not substantiated your theory about the A320 being more aerodynamically efficient. All that has been substantiated is that the A320 and 737 perform differently under different conditions which can be traced back to design requirements

kitplane01 wrote:

flipdewaf wrote:

flipdewaf wrote:

I countered the change from 0.78M to 0.8M by altering wing sweep to 30°. I would imagine that if you were trying to get to 0.85 then you would need a bit more of a sweep and a thinner wing from ~0.12 to 0.1. this would impact the weight but changes to the drag at that level will be lost in the noise and uncertainty of the models. I'll have a go though.

Fred

Aircraft Changes:
Wing area increased to 156m^2
Wing sweep to 30
Span to 42m
Wig T/C from 0.12 to 0.1
MTOW 105000kg
MZFW - 80000kg
Empty weight weight increase ~4t
Available wing tankage ~ 26M^3 (22t)

Mission:
Still air distance 5000nm
Speed 0.85M
DOW - 55500kg
Payload - 20600kg (206pax)
Landing weight - 80187kg
Takeoff weight - 104643kg
Fuel Used = 24455kg
Time taken = 10:30.

Notes:
-Aircraft empty weight goes up
-Aircraft landing weight goes up
-Aircraft takeoff weight goes up
Fuel used goes down (very slightly)
-Flight time reduces
-Fuel Volume Drops (critically) although we know there is space for an ACT.

Although it looks promising because less fuel is used the previous example would actually have more range available and would perform with lower fuel burns than this variant at the shorter ranges dues to the lower (~3%) empty weight. Swings and roundabouts.

Fred

If the MTOW goes from 97 tonnes to 105 tonnes, are you also increasing engine thrust?
Any data on runway required?

Love this kind of thing

Yes to 160kN. https://en.m.wikipedia.org/wiki/Pratt_% ... ey_PW1000G
A320neo family 110kN to 160kN

kitplane01 wrote:

What does "Service ceiling must include a certification factor," mean? What certification factor are you talking about?

I'd guess things like you can't fly higher than you can reach a save altitude in case of cabin pressure loss?
(Again) I'd assume this to be different for ACJ types and commercial transport environment.

kitplane01 wrote:

flipdewaf wrote:

flipdewaf wrote:

I countered the change from 0.78M to 0.8M by altering wing sweep to 30°. I would imagine that if you were trying to get to 0.85 then you would need a bit more of a sweep and a thinner wing from ~0.12 to 0.1. this would impact the weight but changes to the drag at that level will be lost in the noise and uncertainty of the models. I'll have a go though.

Fred

Aircraft Changes:
Wing area increased to 156m^2
Wing sweep to 30
Span to 42m
Wig T/C from 0.12 to 0.1
MTOW 105000kg
MZFW - 80000kg
Empty weight weight increase ~4t
Available wing tankage ~ 26M^3 (22t)

Mission:
Still air distance 5000nm
Speed 0.85M
DOW - 55500kg
Payload - 20600kg (206pax)
Landing weight - 80187kg
Takeoff weight - 104643kg
Fuel Used = 24455kg
Time taken = 10:30.

Notes:
-Aircraft empty weight goes up
-Aircraft landing weight goes up
-Aircraft takeoff weight goes up
Fuel used goes down (very slightly)
-Flight time reduces
-Fuel Volume Drops (critically) although we know there is space for an ACT.

Although it looks promising because less fuel is used the previous example would actually have more range available and would perform with lower fuel burns than this variant at the shorter ranges dues to the lower (~3%) empty weight. Swings and roundabouts.

Fred

If the MTOW goes from 97 tonnes to 105 tonnes, are you also increasing engine thrust?
Any data on runway required?

Love this kind of thing

Thrust levels likely not an issue due to the lower wing loading and increased span.

Runway/takeoff requirements is the next bit of my model to be built but I need a large chunk of time with no interruptions to complete. Luckily a I have a work trip coming up with an AMS-DTW leg to get to grips with it.

Fred


Sent from my iPhone using Tapatalk

Newbiepilot wrote:

The 737NG wing was designed to cruise at 410 in normal operation.

The 737NG is certified for a max ceiling of 41kfeet.
That is quite different to "optimized for 41kfeet cruise".

( A320 family for the same flightlevel.)

afaik one significant restrictor here is ability to descend to save altitude from cruise in limited time
and not aerodynamic optimization.

Newbiepilot wrote:

mjoelnir wrote:

kitplane01 wrote:

What does "Service ceiling must include a certification factor," mean? What certification factor are you talking about?

Because the service ceiling does change with the different use. So it is not a physical limitation, but a certified limitation.

True. An A320 can probably climb to 45000ft under the right conditions. However optimized for efficiency is different from capability. The 737NG wing was designed to cruise at 410 in normal operation. The A320 wasnt. This is an example of different requiremengs and constraints which can explain why the 737 performs differently.

You still have not substantiated your theory about the A320 being more aerodynamically efficient. All that has been substantiated is that the A320 and 737 perform differently under different conditions which can be traced back to design requirements

For the ACJ cruising at 41.000 feet is normal operation. It is the same frame. As you keep insisting, I ask you now to back up your claims with some background information like an article or something. You are always fast to ask for proof, but very reluctant to provide proof for your claims.

mjoelnir wrote:

kitplane01 wrote:

mjoelnir wrote:

Service ceiling must include a certification factor, rather than a physical limitation. The ACJ versions of the A320 family have 41.000 feet service ceiling at the same MTOW.

So I assume that you assume wrong.

What does "Service ceiling must include a certification factor," mean? What certification factor are you talking about?

Because the service ceiling does change with the different use. So it is not a physical limitation, but a certified limitation.

In pilot school I was told that service ceiling is the maximum altitude where you can climb at 100ft/min.

If your aircraft is not RVSM certified, you cannot legally fly over 24,000 ft in the US, but that does not change your service ceiling.

I know some aircraft manufacturers purposefully claim a lower service ceiling because they don't want to do as much testing, and the additional altitude gives no performance advantage. I believe the Learjet 61 is like this.

I know R-44 helicopters must always be within 9000 feet of the ground so they can reach the ground within 5 minutes in case of fire. But that's not a service ceiling, just an additional limitation.

Buy why would an A320/B737 have a certified ceiling lower than the actual ceiling?

kitplane01 wrote:

mjoelnir wrote:

kitplane01 wrote:

What does "Service ceiling must include a certification factor," mean? What certification factor are you talking about?

Because the service ceiling does change with the different use. So it is not a physical limitation, but a certified limitation.

In pilot school I was told that service ceiling is the maximum altitude where you can climb at 100ft/min.

If your aircraft is not RVSM certified, you cannot legally fly over 24,000 ft in the US, but that does not change your service ceiling.

I know some aircraft manufacturers purposefully claim a lower service ceiling because they don't want to do as much testing, and the additional altitude gives no performance advantage. I believe the Learjet 61 is like this.

I know R-44 helicopters must always be within 9000 feet of the ground so they can reach the ground within 5 minutes in case of fire. But that's not a service ceiling, just an additional limitation.

Buy why would an A320/B737 have a certified ceiling lower than the actual ceiling?

To do with de-pressurisation, with a formula based on oxygen making capacity, passenger numbers and time to descend?