sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

Ultra Long Range

Fri Jun 01, 2012 2:01 pm

Will there ever be an aircraft made that can do the longest routes nonstop profitable? 10 000-9500nm. The 77L has to carry too much fuel to make it economical. Or are we at the peak of what we can do with technology? Fuel price will be even greater in the future, this will be a hard nut to crack.

Maybe air travel will become more expensive again? The BWB offers about 30% more lift than a tube with wings, but it does seem to have too many disadvatages for passenger duty. As a freighter it would be really good.

Will it take a huge technological leap from what we have right now?
 
CM
Posts: 623
Joined: Wed Feb 08, 2012 4:17 am

RE: Ultra Long Range

Fri Jun 01, 2012 2:26 pm

The A340-500 and 777-200LR have taught us a few things:

1. The market for this kind of range is very small.
2. Today's technology does not deliver quite enough range to capture some truly coveted ultra-long routes (e.g. SYD-LHR or SIN-ATL)
3. The small economic penalty of the higher gross weights in these current ULH aircraft has been just enough to keep them from being widely accepted in the market.

However, the newest generation of aircraft have moved the dot a bit, with the 787 and A350 demonstrating you can add considerable range over their predecessors AND deliver a significant improvement is economics. Because of that, I would not rule out a 777-8XL or A350-900R being able to achieve these very long range routes at a trip cost that makes them very attractive to certain airlines.
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Fri Jun 01, 2012 2:32 pm

So after 787/A350, where is aviation heading right now? Will there be a slow period until the next major step takes place?
 
User avatar
seabosdca
Posts: 4963
Joined: Sat Sep 01, 2007 8:33 am

RE: Ultra Long Range

Fri Jun 01, 2012 2:49 pm

At a certain point, ULH is just more expensive to fly, no matter how efficient your aircraft gets. You are using more of your fuel to keep fuel in the air, and less of it to keep payload in the air.

Thus to make a ULH route work you need to be able to attract a quite sizeable revenue premium.

SQ has the near-ideal case for such a premium route in SIN-EWR. Even so, the route has been satisfactory at best, never a standout. SIN-LAX has been extremely difficult for them.

So if you are wanting to operate routes 1000-2000 nm (2+-4+ hours flying time!) longer than SIN-EWR, even with a new revolutionary aircraft of some sort, you will need to attract a lot of customers who are willing to pay dearly for that nonstop.

I don't know that there's any route that could possibly attract enough of those customers except LHR-SYD. GRU-NRT is the only other candidate that is even somewhat credible.

Two routes of that length will necessitate no more than 10 aircraft. To put it mildly, that does not demonstrate a business case for building a super-ULH type.
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Fri Jun 01, 2012 3:00 pm

Maybe if we solve the fuel problem it will be more popular, however 19 hours in a seat feels a bit awkward to me at least. Maybe it will have to be that suborbital idea to make it durable, rocket assisted flight to near zero gravity and then a long glide towards the destination. 5 hours LHR-SYD? I don´t see it happen.
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Fri Jun 01, 2012 5:49 pm

Will there be a BWB developed as a freighter? 30% more lift must make a difference? If a BWB could fly as far as a 77L, would this be with 30% less fuel? Or am I thinking wrong here?
 
n92r03
Posts: 355
Joined: Sun Jan 10, 2010 10:46 pm

RE: Ultra Long Range

Fri Jun 01, 2012 6:10 pm

Quoting seabosdca (Reply 3):
SQ has the near-ideal case for such a premium route in SIN-EWR.

FWIW, my seat mate earlier this week on UA's HKG-EWR flight had transited in HKG from SIN. She told me she had done the SQ flight before but the cost was becoming an issue for her company. She also said that SQ was considering adding Y class to that flight...I have no idea if the rumor is true or not as I was under the impression weight was the big issue and keeping the weight down makes the flight doable.

Doing 15+ hours in Y or even J is enough. Any more than that and it just becomes downright uncomfortable. I don't see a plane being engineered to do 18+ hour flights as the demand is just not there.
 
User avatar
Polot
Posts: 4789
Joined: Thu Jul 28, 2011 3:01 pm

RE: Ultra Long Range

Fri Jun 01, 2012 6:58 pm

Quoting sweair (Reply 2):
So after 787/A350, where is aviation heading right now? Will there be a slow period until the next major step takes place?

After the 787/A350/777/Possible A330S/Neo/Whatever is all cleared up by the end of the decade, Airbus and Boeing will probably turn their focus on permanent replacements for the 737/A320, as both companies are making it sound like the MAX/NEO are just stopgaps for the time being.
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Fri Jun 01, 2012 8:06 pm

So a technological slow decade ahead in aviation?
 
User avatar
DocLightning
Posts: 19761
Joined: Wed Nov 16, 2005 8:51 am

RE: Ultra Long Range

Sat Jun 02, 2012 3:11 am

Quoting sweair (Reply 4):
Maybe if we solve the fuel problem it will be more popular, however 19 hours in a seat feels a bit awkward to me at least. Maybe it will have to be that suborbital idea to make it durable, rocket assisted flight to near zero gravity and then a long glide towards the destination. 5 hours LHR-SYD? I don´t see it happen.

You have a very good point. The flight becomes 19-20 hours. At that point, most passengers would actually like a stop to stretch their legs out a bit. The stop stretches the travel time out to maybe 22-24 hours, but that's only an increase of 10-20% in exchange for lower fuel costs and a more comfortable experience.

As it stands, the 77L could probably do SYD-LHR or SYD-JFK in an all-F/J configuration (lower payload than having a Y cabin). There just aren't enough takers to make it work.
-Doc Lightning-

"The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars."
-Carl Sagan
 
User avatar
Stitch
Posts: 23079
Joined: Wed Jul 06, 2005 4:26 am

RE: Ultra Long Range

Sat Jun 02, 2012 3:30 am

Quoting n92r03 (Reply 6):
She also said that SQ was considering adding Y class to that flight...I have no idea if the rumor is true or not as I was under the impression weight was the big issue and keeping the weight down makes the flight doable.

When SQ first started SIN-LAX/LHR the planes were configured with the SpaceBed Business Class seat and an Economy product that was equivalent to domestic First Class in the United States - 20" seat width and 38" seat pitch. SQ found Economy load factors were low and Business yields high so when they introduced their new Business Class hard product (which is likely significantly heavier than the SpaceBed), they removed Economy and put in only Business Class.
 
rwessel
Posts: 2448
Joined: Tue Jan 16, 2007 3:47 pm

RE: Ultra Long Range

Sat Jun 02, 2012 4:03 am

Quoting DocLightning (Reply 9):
As it stands, the 77L could probably do SYD-LHR or SYD-JFK in an all-F/J configuration (lower payload than having a Y cabin). There just aren't enough takers to make it work.

And if not, an all F/J cabin would certainly leave space and mass for a good sized auxiliary fuel tank in the hold, which would not be a big engineering challenge. I can’t imagine it would take Boeing all that long to whip up such a thing if a customer asked.
 
User avatar
DocLightning
Posts: 19761
Joined: Wed Nov 16, 2005 8:51 am

RE: Ultra Long Range

Sat Jun 02, 2012 6:12 pm

Quoting rwessel (Reply 11):
And if not, an all F/J cabin would certainly leave space and mass for a good sized auxiliary fuel tank in the hold, which would not be a big engineering challenge. I can’t imagine it would take Boeing all that long to whip up such a thing if a customer asked.

Right. The trouble is that there is a global market for maybe ten such aircraft. Not worth the certification costs.
-Doc Lightning-

"The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars."
-Carl Sagan
 
User avatar
Stitch
Posts: 23079
Joined: Wed Jul 06, 2005 4:26 am

RE: Ultra Long Range

Sat Jun 02, 2012 11:25 pm

Quoting DocLightning (Reply 9):
As it stands, the 77L could probably do SYD-LHR or SYD-JFK in an all-F/J configuration (lower payload than having a Y cabin). There just aren't enough takers to make it work.

They could probably find enough takers (schedule the flight for the most desirable departure or arrival time).

I expect the real issue is that those seats really help to "pay the rent" for the flight and the Economy Class cabin is likely more there for ancillary revenue. So if you put all your premium cabin passengers on one flight, the all-Economy flights (even on low-CASM aircraft like the A380) probably don't financially pencil out.
 
prebennorholm
Posts: 6419
Joined: Tue Mar 21, 2000 6:25 am

RE: Ultra Long Range

Sun Jun 03, 2012 2:10 am

Quoting rwessel (Reply 11):
...an all F/J cabin would certainly leave space and mass for a good sized auxiliary fuel tank in the hold, which would not be a big engineering challenge. I can’t imagine it would take Boeing all that long to whip up such a thing if a customer asked.

Sure right. But the gain isn't all that much. Cutting pax load in half on a 77L (150 instead of 300) would allow a roughly 8% increase of fuel load (assuming saved cabin furniture weight identical to weight of additional fuel tanks).

A fully loaded 77L carries some 60,000 lbs payload and 365,000 lbs fuel.

Even reducing pax load to one single passenger would extend the potential range capability surprisingly little.

These numbers clearly show how crazily inefficient ULH flight is. On a fully loaded 77L fueled for max range the payload is limited to less than 8% of MTOW, while that figure on a 738 is roughly three times higher.

There is a good reason why the 77W sells so much better than the 77L.
Always keep your number of landings equal to your number of take-offs
 
User avatar
seabosdca
Posts: 4963
Joined: Sat Sep 01, 2007 8:33 am

RE: Ultra Long Range

Sun Jun 03, 2012 5:59 am

Quoting sweair (Reply 2):
So after 787/A350, where is aviation heading right now?

If any one of us somehow knew the answer to this, he or she could get very, very rich.  
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Sun Jun 03, 2012 11:34 am

How high would a near orbital flight be, most fuel spent to reach the peak and then gently glide for the destination?
 
User avatar
Starlionblue
Posts: 17092
Joined: Fri Feb 27, 2004 9:54 pm

RE: Ultra Long Range

Sun Jun 03, 2012 12:15 pm

Quoting sweair (Reply 16):
How high would a near orbital flight be, most fuel spent to reach the peak and then gently glide for the destination?

By definition it would have to reach 100km altitude (de jure threshold of space) to be sub-orbital. And yes, almost all fuel would be used on ascent (and boost stops pretty early in the flight), with the rest used for approach and landing.

If we use an ICBM as an example if intercontinental suborbital flight, boost would be 3-5 minutes, cruise (in free fall) would be about half an hour, and reentry 2 minutes. However since in our case we want to land and not impact, reentry would take longer.

BTW I don't think "gently glide" would be the expression used to describe reentry.  
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Sun Jun 03, 2012 5:26 pm

Is there another way of doing such a long route faster, say 10 hours.. If the aircraft didn't need to go quite the distance towards orbit. The g-forces with rockets would make comfort bad  

How high can air breathing engines go? Could we make LHR-SYD without going spaceship2?
 
rwessel
Posts: 2448
Joined: Tue Jan 16, 2007 3:47 pm

RE: Ultra Long Range

Sun Jun 03, 2012 6:16 pm

Quoting sweair (Reply 16):
How high would a near orbital flight be, most fuel spent to reach the peak and then gently glide for the destination?

Obviously it depends on the distance of the flight, but a 5000mi flight has been kicked around here a few times. A ballistic flight of that length would reach an apogee of about 1500mi.
 
User avatar
Starlionblue
Posts: 17092
Joined: Fri Feb 27, 2004 9:54 pm

RE: Ultra Long Range

Sun Jun 03, 2012 11:24 pm

Quoting sweair (Reply 18):
Is there another way of doing such a long route faster, say 10 hours.. If the aircraft didn't need to go quite the distance towards orbit.

You either go supersonic and conventional or suborbital. Once you're going suborbital, my guess is that it would cost more fuel to use a lower and slower trajectory.

Quoting sweair (Reply 18):
How high can air breathing engines go? Could we make LHR-SYD without going spaceship2?

You don't need to power the whole way up. In fact suborbital flight boost phase is only the first few minutes and in atmosphere (mostly). You're coasting most of the way, even going up. My guess is you could use air breathing engines, in theory.

However turbofans would not work. You'd have to use scramjets to get the required velocity. And you can't use those at low speeds. So now we're talking a hybrid propulsion system. The SR-71 engines were more or less ramjets at high speed, but they were speed limited by the dragging core. If you could lock out the core in ramjet mode, and use supersonic combustion to make it a scramjet, then you would be in business to at least look at prototyping.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
User avatar
DarkSnowyNight
Posts: 1790
Joined: Sun Jan 01, 2012 7:59 pm

RE: Ultra Long Range

Sun Jun 03, 2012 11:54 pm

Quoting rwessel (Reply 11):

And if not, an all F/J cabin would certainly leave space and mass for a good sized auxiliary fuel tank in the hold, which would not be a big engineering challenge. I can’t imagine it would take Boeing all that long to whip up such a thing if a customer asked.

Boeing does already offer auxillary tanks as an option. The native fuel capacity of 47,980gallons (oddly enough, only about 2600 more than what the ER maxes out at) can be augmented up to 54,000. But...

Quoting DocLightning (Reply 12):

Right. The trouble is that there is a global market for maybe ten such aircraft. Not worth the certification costs.

Quite right. There have been, thus far, no takers for that option. So all 777LRs are limited to 47,980 gallons, or just about 321,500lbs.
Be A Perfectionst, You're Nothing If You're Just Another; Something Material, This Isn't Personal...
 
rwessel
Posts: 2448
Joined: Tue Jan 16, 2007 3:47 pm

RE: Ultra Long Range

Mon Jun 04, 2012 4:11 am

Quoting Darksnowynight (Reply 21):
Boeing does already offer auxillary tanks as an option. The native fuel capacity of 47,980gallons (oddly enough, only about 2600 more than what the ER maxes out at) can be augmented up to 54,000. But...

Which would net you what? About an additional 1000nm? For the loss of two-thirds (ouch!) of your paying payload.

Quoting Darksnowynight (Reply 21):
Quite right. There have been, thus far, no takers for that option. So all 777LRs are limited to 47,980 gallons, or just about 321,500lbs.

That certainly says something about the economics...
 
cmf
Posts: 3120
Joined: Sun Jun 12, 2011 11:22 pm

RE: Ultra Long Range

Mon Jun 04, 2012 2:06 pm

Quoting sweair (Reply 8):
So a technological slow decade ahead in aviation?

Not at all. Just focused on other things than additional distance. Ironically this is likely to be more technologically advanced.
Don’t repeat earlier generations mistakes. Learn history for a better future.
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Mon Jun 04, 2012 6:45 pm

Quoting cmf (Reply 23):
Not at all. Just focused on other things than additional distance. Ironically this is likely to be more technologically advanced.

Well after 787/350 there will be max, neo and 777ng...Not very exciting at least for me. Nice power point presentations doesn't do it for me. Boring  
 
User avatar
DarkSnowyNight
Posts: 1790
Joined: Sun Jan 01, 2012 7:59 pm

RE: Ultra Long Range

Mon Jun 04, 2012 7:18 pm

Quoting rwessel (Reply 22):

Which would net you what? About an additional 1000nm? For the loss of two-thirds (ouch!) of your paying payload.

Maybe even that much, yes. Depending on WX conditions, payload, etc. We also have to remember that the more fuel they pack on, the more they have to carry (likely at lower alt as well) for the first part of the flight. Sooner or later those diminishing returns to necessitate a new wing or even a re-evaluation of the mission. Not really hard to see why airlines didn't spring for the extra plumbing...
Be A Perfectionst, You're Nothing If You're Just Another; Something Material, This Isn't Personal...
 
User avatar
DocLightning
Posts: 19761
Joined: Wed Nov 16, 2005 8:51 am

RE: Ultra Long Range

Mon Jun 04, 2012 8:17 pm

Quoting Darksnowynight (Reply 21):
Quite right. There have been, thus far, no takers for that option.

Is it even an option? Mind you, if Tim Clarke went to Boeing and asked for it and promised to buy 50 copies, I'm sure they'd build it. The issue is that the demand has to provide Boeing with some ROI.

Quoting sweair (Reply 24):
Well after 787/350 there will be max, neo and 777ng...Not very exciting at least for me. Nice power point presentations doesn't do it for me. Boring

Flying, for the forseeable future, will continue to be a subsonic, unpleasant, boring affair. Just like it is today. Fancier engines don't change the flying experience much. Pretty LED lighting also adds little to the experience. What matters is the seat comfort and the on-board service. That is not up to the OEM.
-Doc Lightning-

"The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars."
-Carl Sagan
 
User avatar
DarkSnowyNight
Posts: 1790
Joined: Sun Jan 01, 2012 7:59 pm

RE: Ultra Long Range

Tue Jun 05, 2012 2:35 am

Quoting DocLightning (Reply 26):

Is it even an option?

Indeed it is.

http://www.smartcockpit.com/data/pdf.../boeing/B777/systems/B777-Fuel.pdf

If you scroll down to page 5, there is a listing of fuel tank diagrams for the 777 (A through LR w/aux tanks installed), and a capacity chart for all models/options.

***Incidentally, I was incorrect about the capacity with the aux tanks on the LR. It does not bring capacity to 54,000 gallons, but only to 49,765g/333,400 lbs (up from 47,890g/320,800 lbs). I don't why I thought it was the other number.

Quoting DocLightning (Reply 26):
Mind you, if Tim Clarke went to Boeing and asked for it and promised to buy 50 copies, I'm sure they'd build it. The issue is that the demand has to provide Boeing with some ROI.

Sure. And same again for the folding wings option too. If there's a profitable market for it, it really doesn't matter if it makes a lot of sense. Boeing will build it.

Seeing no options taken for the aux tells me that a lot of LR flying is probably as much performance related (e.g. lifting heavier payloads over shorter distances), than straight up range necessity. The extra engine power and strengthened MLG/NLG sets probably help out a bunch for that. In fact, I'd bet the 77L can probably do something like SXM - CDG at MTOW, if needed.

What's strange about this is that it sells a long ranged 777 for the exact opposite reasons 747s sold so well through the '80s.
Be A Perfectionst, You're Nothing If You're Just Another; Something Material, This Isn't Personal...
 
User avatar
DocLightning
Posts: 19761
Joined: Wed Nov 16, 2005 8:51 am

RE: Ultra Long Range

Tue Jun 05, 2012 7:16 pm

I wonder if the extra tanks have been installed on any VIP 777's, or if any VIP 77L's have been built at all. But then again, VIP aircraft carry lower payloads than pax. aircraft, anyway.
-Doc Lightning-

"The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars."
-Carl Sagan
 
Viscount724
Posts: 18974
Joined: Thu Oct 12, 2006 7:32 pm

RE: Ultra Long Range

Tue Jun 05, 2012 10:46 pm

Quoting DocLightning (Reply 28):
I wonder if the extra tanks have been installed on any VIP 777's, or if any VIP 77L's have been built at all. But then again, VIP aircraft carry lower payloads than pax. aircraft, anyway.

There are at least 3 VIP 777s, 2 77Es and 1 77W. Not sure if that's all.


View Large View Medium
Click here for bigger photo!

Photo © Lars Hentschel
View Large View Medium
Click here for bigger photo!

Photo © John Ballantyne


View Large View Medium
Click here for bigger photo!

Photo © Propfreak

 
sunrisevalley
Posts: 4985
Joined: Tue Jul 06, 2004 3:26 am

RE: Ultra Long Range

Wed Jun 06, 2012 1:52 am

Quoting Darksnowynight (Reply 27):
In fact, I'd bet the 77L can probably do something like SXM - CDG at MTOW, if needed.

Not quite, it is good for ~308t TOW on a standard day off SXM's 7700' runway 
 
User avatar
seabosdca
Posts: 4963
Joined: Sat Sep 01, 2007 8:33 am

RE: Ultra Long Range

Wed Jun 06, 2012 5:01 am

Quoting Darksnowynight (Reply 27):
In fact, I'd bet the 77L can probably do something like SXM - CDG at MTOW, if needed.

Field performance aside, I'm not sure a pax 77L taking off at MTOW would even be under MLW after a flight of that length. (No problem for a freighter.)
 
mafi29
Posts: 47
Joined: Sat Nov 20, 2010 10:46 am

RE: Ultra Long Range

Wed Jun 06, 2012 10:53 am

Quoting Darksnowynight (Reply 27):
It does not bring capacity to 54,000 gallons, but only to 49,765g/333,400 lbs (up from 47,890g/320,800 lbs). I don't why I thought it was the other number.

Because it was the right number  
Acording to the Boeing website three optional fuel tanks add up to a total of 53,515 U.S. gallons (202,570 L).
http://www.boeing.com/commercial/777family/pf/pf_lrproduct.html
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Wed Jun 06, 2012 2:35 pm

The 77L is really a big gas tank  
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Fri Jun 08, 2012 1:56 pm

I know airships are slow but would a lighter than air airship be able to do ultra long range flights, that would probably be one long and slow journey? Would it be possible to load that much fuel in an airship to make a 9500nm trip?

And how many passengers would be able to fly on it to pay for it all?
 
User avatar
Starlionblue
Posts: 17092
Joined: Fri Feb 27, 2004 9:54 pm

RE: Ultra Long Range

Fri Jun 08, 2012 11:23 pm

Quoting sweair (Reply 34):
I know airships are slow but would a lighter than air airship be able to do ultra long range flights, that would probably be one long and slow journey? Would it be possible to load that much fuel in an airship to make a 9500nm trip?

No problem really. The energy requirements are way lower. The German airships easily flew transatlantic 80 years ago.

Quoting sweair (Reply 34):
And how many passengers would be able to fly on it to pay for it all?

That's the problem. You need a big airship for not so many passengers. Since the journey would take days you can't pack them in like sardines.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
User avatar
DocLightning
Posts: 19761
Joined: Wed Nov 16, 2005 8:51 am

RE: Ultra Long Range

Sat Jun 09, 2012 6:58 am

Quoting sweair (Reply 34):
know airships are slow but would a lighter than air airship be able to do ultra long range flights, that would probably be one long and slow journey? Would it be possible to load that much fuel in an airship to make a 9500nm trip?

Yes, but why? They move at about 100-125 km/h and they're horribly sensitive to weather. They can't pass over the Himalayas safely, either. They have to be positively ginormous relative to their miniscule payload (ever seen the plans of Hindenburg?), and the fares would be much larger because you would have to give each passenger a stateroom, just as in the days of the Zeppelins. This link gives you an idea of the miniscule volume that Hindenburg dedicated to passengers with respect to the overall structure. http://www.airships.net/hindenburg

Today, there are a few rigid airships in passenger operation. The SF Bay Area has a few. A two-hour ride runs US$1000/person. By contrast, a one-way trip aboard Hindenburg cost about US$5,000 in today's money.

Airships will never again be used for transport any more than steamships will.
-Doc Lightning-

"The sky calls to us. If we do not destroy ourselves, we will one day venture to the stars."
-Carl Sagan
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Sat Jun 09, 2012 9:24 am

A BWB with helium bladders then? Some how we have to solve the 9500nm route, I know its no problem, but for the fun of it? I like creative thinking for non existent problems.
 
User avatar
seabosdca
Posts: 4963
Joined: Sat Sep 01, 2007 8:33 am

RE: Ultra Long Range

Sat Jun 09, 2012 6:52 pm

Quoting sweair (Reply 37):
A BWB with helium bladders then? Some how we have to solve the 9500nm route, I know its no problem, but for the fun of it? I like creative thinking for non existent problems.

The trouble is that we have already come up with a solution for that route which is awfully hard to beat, given physics: break it into two ~5000 nm pieces.  
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Sat Jun 09, 2012 7:19 pm

Quoting seabosdca (Reply 38):
The trouble is that we have already come up with a solution for that route which is awfully hard to beat, given physics: break it into two ~5000 nm pieces.

If I have to fly a long tiresome route I rather get it over with as quickly as I can. Not that I don't like Singapore or Bangkok, I just hate deboarding in the middle of being very sleepy and having to wait for the fueling and cleaning. Its adding two hours to a long journey.

And why should we give up, we should strive to solve problems. If mankind didn't want to evolve we would still live in caves fighting lions..
 
User avatar
Starlionblue
Posts: 17092
Joined: Fri Feb 27, 2004 9:54 pm

RE: Ultra Long Range

Sun Jun 10, 2012 2:34 am

Quoting seabosdca (Reply 38):
The trouble is that we have already come up with a solution for that route which is awfully hard to beat, given physics: break it into two ~5000 nm pieces.

Approaching, landing, taxiing, taxiing again, taking off and climbing is a process which uses a lot of fuel. Extending a flight also uses a lot of fuel. It all depends on which is cheaper for the route and aircraft. As technology progresses, the economically flyable non-stop route length increases.

In the 70s, you couldn't do LHR-SIN non stop economically. In the late 80s you could, and it is now cheaper to fly non-stop than with a stop.

The question is whether development of tubes with wings will ever reach the point where LHR-SYN without a stop is cheaper than with a stop.

Quoting sweair (Reply 39):
f I have to fly a long tiresome route I rather get it over with as quickly as I can. Not that I don't like Singapore or Bangkok, I just hate deboarding in the middle of being very sleepy and having to wait for the fueling and cleaning. Its adding two hours to a long journey.

Word...
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
tdscanuck
Posts: 8572
Joined: Wed Jan 11, 2006 7:25 am

RE: Ultra Long Range

Sun Jun 10, 2012 2:49 am

Quoting Starlionblue (Reply 40):
The question is whether development of tubes with wings will ever reach the point where LHR-SYN without a stop is cheaper than with a stop.

The economics have almost nothing to do with the development of the tube with wings and everything to do with cost of fuel and cost of time. Lots of routes become economically viable at current ticket prices if fuel prices drop.

Tom.
 
thegeek
Posts: 1330
Joined: Mon Nov 26, 2007 7:20 am

RE: Ultra Long Range

Sun Jun 10, 2012 4:48 am

Quoting Starlionblue (Reply 40):
In the 70s, you couldn't do LHR-SIN non stop economically. In the late 80s you could, and it is now cheaper to fly non-stop than with a stop.

With the aircraft of that day. Even today, I reckon if you have an A333 it will be more economic on LHR-SIN making a stop than doing it non stop.

Depends on the design range.
 
User avatar
Starlionblue
Posts: 17092
Joined: Fri Feb 27, 2004 9:54 pm

RE: Ultra Long Range

Sun Jun 10, 2012 10:16 am

Quoting tdscanuck (Reply 41):
The economics have almost nothing to do with the development of the tube with wings and everything to do with cost of fuel and cost of time. Lots of routes become economically viable at current ticket prices if fuel prices drop.

Well put. Always learning from you, Tom.

However with advances in technology and lower fuel usage (supercritical wings, big fans, etc...) the design ranges which are economically reasonable increase regardless of fuel price, no?

Quoting thegeek (Reply 42):
Quoting Starlionblue (Reply 40):
In the 70s, you couldn't do LHR-SIN non stop economically. In the late 80s you could, and it is now cheaper to fly non-stop than with a stop.

With the aircraft of that day. Even today, I reckon if you have an A333 it will be more economic on LHR-SIN making a stop than doing it non stop.

Depends on the design range.

Yes of course. But what I meant was that in the 70s building an airliner with a LHR-SIN design range was uneconomical, while in the 80s it was a reasonable proposition due to advances in technology.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Sun Jun 10, 2012 12:15 pm

A BWB would have some 20% more lift in the same size of frame as a tube+wings? The question is how do that extra lift get used in the best way? I wont care about the windows and exits, just the physics now, would a BWB do a 9500nm route cheaper than a tube+wings?
 
tdscanuck
Posts: 8572
Joined: Wed Jan 11, 2006 7:25 am

RE: Ultra Long Range

Sun Jun 10, 2012 1:34 pm

Quoting Starlionblue (Reply 43):
However with advances in technology and lower fuel usage (supercritical wings, big fans, etc...) the design ranges which are economically reasonable increase regardless of fuel price, no?

Yes, absolutely. I apologize if it seemed like I was implying otherwise. As long as technology focuses on reduced fuel burn (which is has for about 30 years now) then the economical range will keep going up for constant fuel price.

My point was just that the improvements in technology are typically in the low single digit percentage (you can get low double digits with major step changes but that only happens about once every 30-40 years right now) while the changes in fuel price are in the high double or low triple digits over similar timeframes. The fluctuation in fuel price completely overwhelms the technology aspect for long term forecasting.

Quoting sweair (Reply 44):
A BWB would have some 20% more lift in the same size of frame as a tube+wings?

Not really...lift is always going to be equal to weight (minus a very small delta during transients). The BWB will generate exactly as much lift as the same sized tube+wings. The BWB advantage is in drag.

Quoting sweair (Reply 44):
The question is how do that extra lift get used in the best way? I wont care about the windows and exits, just the physics now, would a BWB do a 9500nm route cheaper than a tube+wings?

A BWB has less drag for its weight (it has a better lift/drag ratio). So, to move the same weight, the BWB engines don't have to work as hard and don't need to burn as much fuel. Thus the same amount of fuel (same fuel cost) takes the BWB farther.

Tom.
 
User avatar
Starlionblue
Posts: 17092
Joined: Fri Feb 27, 2004 9:54 pm

RE: Ultra Long Range

Sun Jun 10, 2012 1:55 pm

Quoting tdscanuck (Reply 45):
Quoting sweair (Reply 44):
A BWB would have some 20% more lift in the same size of frame as a tube+wings?

Not really...lift is always going to be equal to weight (minus a very small delta during transients). The BWB will generate exactly as much lift as the same sized tube+wings. The BWB advantage is in drag.

I love how you correctly nitpick. Lift will always by definition be equal to weight of course. However the entire point of having an airfoil that is more sophisticated than a flat piece of metal is that it generates lift with a minimum of drag. (And you can put fuel in it.) The flat piece of metal will generate lift (as will a paper aircraft with flat wings); it just doesn't do it very well.

But you knew that and I knew that. 
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Sun Jun 10, 2012 2:12 pm

Well the wing area that creates lift would be much larger in a BWB, the B2 can carry an impressive cargo for its size IMO.
 
User avatar
Starlionblue
Posts: 17092
Joined: Fri Feb 27, 2004 9:54 pm

RE: Ultra Long Range

Sun Jun 10, 2012 2:18 pm

Quoting sweair (Reply 47):

Well the wing area that creates lift would be much larger in a BWB, the B2 can carry an impressive cargo for its size IMO.

Yes but watch out for skin friction draaaaaaaaaaaaaaaaaaaaaag......
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
sweair
Topic Author
Posts: 1816
Joined: Sun Nov 20, 2011 9:59 am

RE: Ultra Long Range

Sun Jun 10, 2012 2:51 pm

Quoting Starlionblue (Reply 48):
Yes but watch out for skin friction draaaaaaaaaaaaaaaaaaaaaag......

So there is no low hanging fruit to pick from the BWB? I had the impression BWB was the future of aviation  
Oh well my interest in aviation technology might just die then.

Who is online

Users browsing this forum: No registered users and 16 guests