Breathe
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Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 2:47 pm

Given the number of concurrent threads surrounding the A380 shutdown. I thought I'd ask this question in a new thread.

While there's no doubt that the end of the manufacture quad engine passenger plane is now a reality. I wondered if there is a potential for it to come back in the future, but not as we currently know it. I was more thinking about hybrid/electric powered engines.

I'm sure a number of folk are aware that Rolls-Royce, Siemens & Airbus are working on the E-Fan X. Somehow I doubt that if/when this engine initially arrives that it will be as powerful (and probably more importantly) reliable as a conventional jet engine. This leads me to wonder if/when these engines appear, if we'll see the return of quad engine passenger planes of a different kind i.e. ones with 2 x traditional jet engines and 2 x electric engines.

What are peoples thoughts on this?
 
StudiodeKadent
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 2:55 pm

I don't know the technology enough to discuss it, but quads (in the sense of four jet engines) just have higher maintenance and running costs. They had a role when twins couldn't do the majority of missions. We're now in a world where twins are doing the world's longest flights (like PER - LHR, SIN - EWR, SIN - SFO, etc).

Give us either a radical technological shift or an entirely unprecedented mission. Then we'll talk about the necessity of quads.

But we're in a world where Project Sunrise can theoretically happen with twinjets.

If the E-Fan X is a radical redefinition of the technological space we'll need to talk about that. But until then?

Yeah. Quads aren't necessary. Unless you need to haul a lot of freight.
 
Ziyulu
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 2:55 pm

I think it would take one disaster of a twin engine plane on a long haul flight, where the regulation will be changed.
 
Breathe
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 2:59 pm

Ziyulu wrote:
I think it would take one disaster of a twin engine plane on a long haul flight, where the regulation will be changed.

Given that we now have 737's criss crossing the Atlantic without any incident for many years, why would one incident change this?
 
Ziyulu
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 3:06 pm

In the 80s, wasn't there a regulation that required trans-Pacific flights to have at least 3 engines or more?
 
Breathe
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 3:10 pm

Ziyulu wrote:
In the 80s, wasn't there a regulation that required trans-Pacific flights to have at least 3 engines or more?

Yup, which is why the potential of the 757 was never fully realised back then.
 
Jetty
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 3:10 pm

Are there any routes left that demand 3 or more engines with current regulations? Crossing the South-Pacific from Australia to South America i.e.?
 
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 3:18 pm

Ziyulu wrote:
In the 80s, wasn't there a regulation that required trans-Pacific flights to have at least 3 engines or more?


No, before ETOPS the rule was twins had to remain within 60 minutes of a suitable alternate. There were some minor exceptions. The rule wasn’t specific to any region. In fact, we’re it not for the Cold War, twins with sufficient range, could have operated out of ANC to Asia. The 757 probably the only one with the range
 
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 3:22 pm

Ziyulu wrote:
In the 80s, wasn't there a regulation that required trans-Pacific flights to have at least 3 engines or more?


ETOPS: Extended Twin Operations, or, colloquially, Engines Turning Or Passengers Swimming.

The original trans-Atlantic and trans-Pacific aircraft all had four engines, as engine technology at the time required it. Even the first Boeing 747's barely had enough power for certification.

But like all technologies, trial and error led to refinements, and engines became more powerful and, most importantly, more reliable.

ETOPS has different levels of certification. Originally, two-engine aircraft were restricted to 60 minutes from the nearest diversion airport. If I remember right, it was TWA that extended this flying time to 120 minutes, and then to 180 minutes. This then put Hawai'i in range of twin-engine aircraft, followed by more and more airlines removing the L-1011 and DC-10's from these routes, and "right-sizing" their oceanic routes to 767's and 757's, while keeping the bigger aircraft for high density routes.

As far as quads go, get on one while you can - Boeing's last was the 747-8, which, thankfully, I have flown (yeah me!!), and with the announcement of the end of production of the A380, quads will be a thing of the past, as the A340 is out of production (correct?).

Will we ever go to single engine airplanes? That I can't answer, but who knows?
 
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 3:33 pm

We have single engine planes. Usually general aviation aircraft.
 
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 3:39 pm

They could make a Airbus 340neo I guess ...
 
douwd20
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 3:40 pm

Ziyulu wrote:
I think it would take one disaster of a twin engine plane on a long haul flight, where the regulation will be changed.


No. That will never happen. ETOPS is here to stay. Quad engines are dead forever. They have proven themselves for decades now. What is this love affair for four engines in a world of over the top CO2 emissions? Is everyone ignoring the record high temperatures across the planet?
 
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 3:41 pm

There will be new quads. Guaranteed. But they'll be electric.
 
VSMUT
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 3:43 pm

Breathe wrote:
Given the number of concurrent threads surrounding the A380 shutdown. I thought I'd ask this question in a new thread.

While there's no doubt that the end of the manufacture quad engine passenger plane is now a reality. I wondered if there is a potential for it to come back in the future, but not as we currently know it. I was more thinking about hybrid/electric powered engines.

I'm sure a number of folk are aware that Rolls-Royce, Siemens & Airbus are working on the E-Fan X. Somehow I doubt that if/when this engine initially arrives that it will be as powerful (and probably more importantly) reliable as a conventional jet engine. This leads me to wonder if/when these engines appear, if we'll see the return of quad engine passenger planes of a different kind i.e. ones with 2 x traditional jet engines and 2 x electric engines.

What are peoples thoughts on this?


I doubt we will see a return to more than 2 engines due to concerns about reliability. If it isn't reliable enough, it won't go on an aircraft, simple as that. Besides, electrical engines are solid as tanks when it comes to reliability - theoretically they only have one movable part after all.

But I do believe there is a very good chance that more than 2-engined aircraft will happen again. It is far from certain that future engine technology will scale the same way turbofans have. Hybrid-electric aircraft would need a generator, although in theory an oversized APU could provide this. What if a groundbreaking new improvement comes along that can't scale up to the size of a GE90? In that case, 4x smaller engines could definitely be the way forwards. Electrical propulsion could find us with aircraft powered by 20 tiny engines. But only time will tell.

Don't forget that the A340-300 proved to be economically competitive with the 777-200ER, despite having 4 engines, and the original plans called for the A340 to be powered by the much better [on paper] P&W Superfan. It isn't a foregone conclusion that 2 is better than 4.
 
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 3:47 pm

I think the only route where quads are used for regulations are Australia to South America due to CAPA Australia and no diversion points on Antarctica. LATAM do operate 789 on the same routes but I guess they get a pass for not being under CAPA regulation.

Personally, I think if the market demands sufficient numbers of VLA frames larger than 777X, it will be after a few decades when the engine technology as well as other advancements would enable producing 500 seat twins. Those routes will mostly be slot restricted hub to hub which means practical range up to 5500nm should suffice so the aircraft won't need super high MTOW for loading massive amount of fuels which requires more thrust aka quads.
 
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 3:56 pm

Why are people talking as if ETOPS isn't safe and proven. If passengers really cared, the A346 would have outsold the 77W.

Because of support equipment (e.g , another nacelle), a large engine only weights 1.5 to 2 tons more than the 4.5 ton engine. Every additional engine adds drag inside the engine flow path and the nacelle. The ratio of wet area (drag) to flow area (thrust) goes down as the engine size increases. Thus compressor and turbine efficiency increase with thrust.

Only a few outspoken people demand quads. Fine, pay a premium to fly A380s or 747s. They still exist.

But considering how much premium traffic has been lost to Gulfstream or Bombardier business Jets, it is obvious how people have booted; time is money. Fly a direct flight. Cities without enough airport capacity will just have to be bypassed.

StudiodeKadent wrote:
I don't know the technology enough to discuss it, but quads (in the sense of four jet engines) just have higher maintenance and running costs. They had a role when twins couldn't do the majority of missions. We're now in a world where twins are doing the world's longest flights (like PER - LHR, SIN - EWR, SIN - SFO, etc).

Give us either a radical technological shift or an entirely unprecedented mission. Then we'll talk about the necessity of quads.

But we're in a world where Project Sunrise can theoretically happen with twinjets.

If the E-Fan X is a radical redefinition of the technological space we'll need to talk about that. But until then?

Yeah. Quads aren't necessary. Unless you need to haul a lot of freight.

That sums it up. The technological shift is BWBs. Due to the use of only drag rudders, they cannot be a twin: 3 and 4 engine concepts exist. However, BWBs have to be large (300+ seats) to achieve their savings.

I suspect there will be development if a twin BWB (engines closer to centerline) as I suspect duct losses will be less expensive than engine #3 or #4.

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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 3:59 pm

Ziyulu wrote:
In the 80s, wasn't there a regulation that required trans-Pacific flights to have at least 3 engines or more?

That was tied up with the beginning of ETOPS

https://en.wikipedia.org/wiki/ETOPS
 
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 4:50 pm

Breathe wrote:
Ziyulu wrote:
In the 80s, wasn't there a regulation that required trans-Pacific flights to have at least 3 engines or more?

Yup, which is why the potential of the 757 was never fully realised back then.


Are you seriously suggesting that 757 did (or even could) have trans-Pacific range with meaningful payload??
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Breathe
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Re: Potential of future Quad Engine passenger planes

Thu Feb 14, 2019 5:00 pm

PW100 wrote:
Breathe wrote:
Ziyulu wrote:
In the 80s, wasn't there a regulation that required trans-Pacific flights to have at least 3 engines or more?

Yup, which is why the potential of the 757 was never fully realised back then.


Are you seriously suggesting that 757 did (or even could) have trans-Pacific range with meaningful payload??

Yikes! I had a brain freeze moment and somehow misread that as trans-atlantic. :banghead:

My bad. :lol:
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 1:57 am

I honestly do not think it's a fair comparison when people say the 779 would have similar capacity to the 744. The 744 is a bigger plane and the passengers are more spread out. It just like saying a Toyota Yaris has the same capacity of a Toyota Avalon. Both can seat 5 passengers, but the Avalon offers much more comfort.
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 2:16 am

Ziyulu wrote:
I honestly do not think it's a fair comparison when people say the 779 would have similar capacity to the 744. The 744 is a bigger plane and the passengers are more spread out. It just like saying a Toyota Yaris has the same capacity of a Toyota Avalon. Both can seat 5 passengers, but the Avalon offers much more comfort.

The Yaris does so at 195 passenger mpg, the Avalon at 110.
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 2:25 am

PSAatSAN4Ever wrote:
Will we ever go to single engine airplanes? That I can't answer, but who knows?


wouldn't that be very unsafe? a single engine airliner would be done after a bit of damage to that single engine. dual engines are probably the absolute minimum because they provide some security in case one of them fails.
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PSAatSAN4Ever
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 2:33 am

emuwarveteran wrote:
PSAatSAN4Ever wrote:
Will we ever go to single engine airplanes? That I can't answer, but who knows?


wouldn't that be very unsafe? a single engine airliner would be done after a bit of damage to that single engine. dual engines are probably the absolute minimum because they provide some security in case one of them fails.


At the current time, I agree 100%. I'd have WAY too many questions!
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 2:41 am

I doubt it. As mentioned before, my best bet for a new quad (if any) would be some sort of electric aircraft or some other new groundbreaking technology that would be better off with 4 engines.
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 2:48 am

Ziyulu wrote:
I honestly do not think it's a fair comparison when people say the 779 would have similar capacity to the 744. The 744 is a bigger plane and the passengers are more spread out. It just like saying a Toyota Yaris has the same capacity of a Toyota Avalon. Both can seat 5 passengers, but the Avalon offers much more comfort.

779 is longer than 773 and has wider cabin width because of thinner interior cabin walls. 773 is already close in capacity to 744. So it's safe to say that 779 will have quite SIMILAR (not the SAME) cabin area to the 744.
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 2:53 am

Ziyulu wrote:
I think it would take one disaster of a twin engine plane on a long haul flight, where the regulation will be changed.


A Quad is twice as likely to suffer an unrelated dual engine failure, and operates with far less regulations governing safety. History and Statistics have shown quads to be a bad bet, as advancing reliability coupled with regulatory oversight have pushed twins ahead in safety.

Quads are also more likely to suffer a related engine failure that takes out all engines than a ETOPS twin. Thanks to those ETOPS regulations designed exactly to prevent that. No one mechanic wrecking all engines with a single repeated mistake.
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 3:37 am

VSMUT wrote:
Don't forget that the A340-300 proved to be economically competitive with the 777-200ER, despite having 4 engines, and the original plans called for the A340 to be powered by the much better [on paper] P&W Superfan. It isn't a foregone conclusion that 2 is better than 4.


I don’t think you can make this statement about the A340-300 at all. The 777-200ER was enormously successful in comparison on sales, and that wouldn’t have happened if airlines could economically operate the A340-300.
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 3:47 am

N328KF wrote:
VSMUT wrote:
Don't forget that the A340-300 proved to be economically competitive with the 777-200ER, despite having 4 engines, and the original plans called for the A340 to be powered by the much better [on paper] P&W Superfan. It isn't a foregone conclusion that 2 is better than 4.


I don’t think you can make this statement about the A340-300 at all. The 777-200ER was enormously successful in comparison on sales, and that wouldn’t have happened if airlines could economically operate the A340-300.

Numbers of 340-300 vs 777-200ER was in 1:2 ratio with 200/400 aircrafts made for each of them. That's not an enormous different
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c933103
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 3:50 am

Surely there will still be some quad-engine planes like Airbus A400M or Kawasaki P1, but the problem is whether airlines will use them in passenger services
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 4:00 am

c933103 wrote:
N328KF wrote:
VSMUT wrote:
Don't forget that the A340-300 proved to be economically competitive with the 777-200ER, despite having 4 engines, and the original plans called for the A340 to be powered by the much better [on paper] P&W Superfan. It isn't a foregone conclusion that 2 is better than 4.


I don’t think you can make this statement about the A340-300 at all. The 777-200ER was enormously successful in comparison on sales, and that wouldn’t have happened if airlines could economically operate the A340-300.

Numbers of 340-300 vs 777-200ER was in 1:2 ratio with 200/400 aircrafts made for each of them. That's not an enormous different


Only 100% more. I am sure you are right that the number is meaningless, as is the fact that the 777-200ER was the benchmark Airbus targeted with the A350-900.
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VSMUT
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 12:05 pm

c933103 wrote:
N328KF wrote:
VSMUT wrote:
Don't forget that the A340-300 proved to be economically competitive with the 777-200ER, despite having 4 engines, and the original plans called for the A340 to be powered by the much better [on paper] P&W Superfan. It isn't a foregone conclusion that 2 is better than 4.


I don’t think you can make this statement about the A340-300 at all. The 777-200ER was enormously successful in comparison on sales, and that wouldn’t have happened if airlines could economically operate the A340-300.

Numbers of 340-300 vs 777-200ER was in 1:2 ratio with 200/400 aircraft made for each of them. That's not an enormous different



You are making the mistake of only comparing total sales. Slightly more airlines chose the A340-300 over the 777-200ER. Boeing just ran with a couple of massive ones.

29 airlines went for the A340-300. 26 went for the 777-200ER.

It should probably also be factored into the equation that Boeing went to great lengths to get the 777-200ER in at several airlines, including buying back A340-300s and converting 747 orders. Airbus was also a relatively unknown quantity at the time, whereas Boeing already had a strong following.
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 12:43 pm

VSMUT wrote:
c933103 wrote:
N328KF wrote:

I don’t think you can make this statement about the A340-300 at all. The 777-200ER was enormously successful in comparison on sales, and that wouldn’t have happened if airlines could economically operate the A340-300.

Numbers of 340-300 vs 777-200ER was in 1:2 ratio with 200/400 aircraft made for each of them. That's not an enormous different



You are making the mistake of only comparing total sales. Slightly more airlines chose the A340-300 over the 777-200ER. Boeing just ran with a couple of massive ones.

29 airlines went for the A340-300. 26 went for the 777-200ER.

It should probably also be factored into the equation that Boeing went to great lengths to get the 777-200ER in at several airlines, including buying back A340-300s and converting 747 orders. Airbus was also a relatively unknown quantity at the time, whereas Boeing already had a strong following.


Another way to say the same thing would be: “Boeing won the large, important campaigns.” As for the vairiety of tails, is that important for a model collection? Because it is otherwise not very relevant now. I really fail to understand how you are, after the market has spoken, doubting the success of the 777-200ER. Fantasy land. Citing the quantity of customers is illustration of this.

In case you need more evidence, look at how quickly A340s were shifted from first-tier to second-tier customers. Two decades later, maybe half of 777-200ERs are still with their original customers, albeit possibly in altered roles. In many cases (AA, UA) some routes were upsized to the 777-300ER, which is the real family success story, and there is no doubting that placed a stake in the heart of the A340. The -300ER owes its success to the -200ER.
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Ziyulu
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 1:41 pm

For the gates with 3 air bridges, is it possible to use all 3 air bridges to board a single deck plane like a 773 or 350?
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 1:54 pm

Ziyulu wrote:
For the gates with 3 air bridges, is it possible to use all 3 air bridges to board a single deck plane like a 773 or 350?


No, as those planes have only 2 front doors (and the 3rd bridge is too high anyway).
 
xjetflyer2001
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 2:10 pm

I'd say the next quad would be for a supersonic transport of some sort, I doubt we will see anymore quads in the traditional sense of two engines hanging off either wing.
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 2:36 pm

XT6Wagon wrote:
Ziyulu wrote:
I think it would take one disaster of a twin engine plane on a long haul flight, where the regulation will be changed.


A Quad is twice as likely to suffer an unrelated dual engine failure, and operates with far less regulations governing safety. History and Statistics have shown quads to be a bad bet, as advancing reliability coupled with regulatory oversight have pushed twins ahead in safety.

Quads are also more likely to suffer a related engine failure that takes out all engines than a ETOPS twin. Thanks to those ETOPS regulations designed exactly to prevent that. No one mechanic wrecking all engines with a single repeated mistake.


Do you have a case where all four engines were taken out by an engine failure? Jets, not pistons. The EDTO regs make extended operations similar regardless of engine count. The record of modern four-engine types is pretty similar to twins on engine failures.

GF
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 3:43 pm

GalaxyFlyer wrote:
XT6Wagon wrote:
Ziyulu wrote:
I think it would take one disaster of a twin engine plane on a long haul flight, where the regulation will be changed.


A Quad is twice as likely to suffer an unrelated dual engine failure, and operates with far less regulations governing safety. History and Statistics have shown quads to be a bad bet, as advancing reliability coupled with regulatory oversight have pushed twins ahead in safety.

Quads are also more likely to suffer a related engine failure that takes out all engines than a ETOPS twin. Thanks to those ETOPS regulations designed exactly to prevent that. No one mechanic wrecking all engines with a single repeated mistake.


Do you have a case where all four engines were taken out by an engine failure? Jets, not pistons. The EDTO regs make extended operations similar regardless of engine count. The record of modern four-engine types is pretty similar to twins on engine failures.

GF


Typically quad engine failures are due to fuel contamination, or stuff like this: https://en.wikipedia.org/wiki/British_Airways_Flight_9
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Ziyulu
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 3:51 pm

But if there was fuel contamination, it would be equally bad for a twin engine. At least with 4 engines, you have 4 options to restart versus 2.
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 3:59 pm

emuwarveteran wrote:
PSAatSAN4Ever wrote:
Will we ever go to single engine airplanes? That I can't answer, but who knows?


wouldn't that be very unsafe? a single engine airliner would be done after a bit of damage to that single engine. dual engines are probably the absolute minimum because they provide some security in case one of them fails.


I agree. There have been enough in-flight shutdowns of one engine that would have been disasters with only a single engine aircraft.

The only flights that had a dual engine (or more) loss had other factors involved. A few examples: US Airways 1549 (birds), Air Canada 143 'Glimli Glider' & Air Transat 236 (fuel starvation) and British Airways Flight 9 (volcanic dust ingestion).
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 4:01 pm

Ziyulu wrote:
But if there was fuel contamination, it would be equally bad for a twin engine. At least with 4 engines, you have 4 options to restart versus 2.


Four engines offers no safety with contaminated fuel.
 
Ziyulu
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 4:28 pm

If fuel was contaminated, there is a chance that the engine would still run. Would you rather have 2 chances of it running or 4?
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 4:46 pm

Finn350 wrote:
Ziyulu wrote:
For the gates with 3 air bridges, is it possible to use all 3 air bridges to board a single deck plane like a 773 or 350?


No, as those planes have only 2 front doors (and the 3rd bridge is too high anyway).

Whilst AMS doesn't have 3 Air Bridges, there only being 2 forward doors needn't nescessarily mean that that would limit it to 2 bridges on a single deck Aircraft.

 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 5:00 pm

Ziyulu wrote:
If fuel was contaminated, there is a chance that the engine would still run. Would you rather have 2 chances of it running or 4?


Well, I've flown transatlantic on two-engine planes, so I judge the risk to be fairly low.

I still maintain that outside of a freak event, a double failure of engines is very improbable, or that the cause of such a failure would likely affect all engines.

I'm much more worried about any number of things that could happen outside of that, like being in a car accident on the way to the airport.

Life's a big risk. Don't take silly risks, but the biggest risk is being so scared as to do nothing.

The 747, A340 and A380 are cool too. I'd fly them, but I wouldn't make my decision contingent on the number of engines.
 
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Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 5:16 pm

JetBuddy wrote:
There will be new quads. Guaranteed. But they'll be electric.

In order for electric planes to be viable there has to be an electric source with the same or better power density to jet fuel. This is conceivable with fuel cells, but not at present with batteries. And with batteries you do not have the advantage of having fuel burn lighten the plane as the flight progresses. So at this point we need technology to safely store and transport hydrogen and tanks for it compatible with aircraft. That is not an easy problem to solve.
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RamblinMan
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Joined: Sat Oct 09, 2010 3:57 pm

Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 5:22 pm

JetBuddy wrote:
There will be new quads. Guaranteed. But they'll be electric.

Bingo.

With new propulsion technology, the configuration and even shape may change radically. But as long as we are using anything resembling current turbofans, every plane from here on out will be a twin-engine tube with wings. There are very few places left in the world out of ETOPS range, and the few air routes which cross these areas don't warrant the cost of developing mission-specific aircraft. Sucks for enthusiasts, but that's the way it is.
 
Ziyulu
Posts: 520
Joined: Thu Oct 13, 2016 10:35 am

Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 5:25 pm

I agree my decision would not be whether the plane has two or four engines, but if all else equal. Price, convenience, and time, and I was given a choice, I would choose a plane with four engines.
 
emuwarveteran
Posts: 134
Joined: Mon Jun 18, 2018 4:49 pm

Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 6:07 pm

electric planes will be very interesting. it'll be like watching the beginning of aviation all over again.
CL CRJ9, W6 A320
 
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Veigar
Posts: 397
Joined: Sat Jun 27, 2015 4:09 pm

Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 6:15 pm

You say quads have no future but we still have B-52s with 8 engines flying around since the 50s.

They'll all have a purpose.
 
wave46
Posts: 148
Joined: Mon Jan 29, 2018 12:02 am

Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 6:22 pm

Veigar wrote:
You say quads have no future but we still have B-52s with 8 engines flying around since the 50s.

They'll all have a purpose.


True, but that's not because of any inherent advantages of 8 engines.

It's more a case of 'they're paid for' and they don't accumulate enough flying hours to really justify a re-engine program.

In commercial circles (i.e. driven by profit, not defence) outside of a few niches, 4-engine airliners are simply not cost-effective.
 
ikramerica
Posts: 14828
Joined: Mon May 23, 2005 9:33 am

Re: Potential of future Quad Engine passenger planes

Fri Feb 15, 2019 6:33 pm

Ziyulu wrote:
I honestly do not think it's a fair comparison when people say the 779 would have similar capacity to the 744. The 744 is a bigger plane and the passengers are more spread out. It just like saying a Toyota Yaris has the same capacity of a Toyota Avalon. Both can seat 5 passengers, but the Avalon offers much more comfort.

The 779 is as big as the 744. It’s 12cm narrower inside (0.4” per pax) but with the same floor area (within 5%) and more cargo space. Accounting for the wasted floor space on the upper deck of the 747 (slanted walls), the wasted space required for a stair, and the “wasted” 12cm wider interior, floor areas are comparable if not slightly tipped to the 779.

It means though the 747 could have 17.5” seats at 10Y, with the same aisles, the 779 has 17.2” seats, which was often the standard size for 744 seats anyway. Some carriers even used 17” for no good reason other than commonality with the 77W.
Of all the things to worry about... the Wookie has no pants.

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