ytz
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Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 2:06 pm

I am engaged in a debate with someone about the environmental merits of Porter's Q400 operation from YTZ vs. Air Canada's use of the A320 or A321 operating from Montreal for short-haul (to Ottawa and Montreal). What do forumers think is more environmentally friendly (read fuel efficient)? If I were to guess without doing the math, I'd say that the Q bests the A321 simply because it hits cruise much quicker. Am I wrong?
 
Boeing4ever
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 2:15 pm

Wrong question to ask IMHO.

These are two very different machines.

In general, turboprops are more efficient. But AC may need larger a/c to fullfill demand that Porter doesn't have. Thus for Porter, Q400 is the optimum choice. For AC, it's the 32X.

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ytz
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 2:19 pm

Boeing4ever,

I understand the aviation business aspect of it. I just happen to be debating some enviro-idealist who detest the Island airport and the Q400 and thinks that for the sake of the environment every Montreal or Ottawa bound passenger should hop on an AC A321....or in his dream world even a B777.
 
ytz
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 2:26 pm

I've seen some good analysis on A.net by LAXDESI and KESSJE on similar topics. I was hoping they'd pitch in.
 
YYZatcboy
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 2:26 pm

If you are looking at overall trip efficiency I really think it depends more on the distance to the airport than the aircraft type used. Both aircraft are efficient more or less equally I would imagine if fully loaded. While the A32x burns more fuel, it carries more passengers, and the Q burns less and carries less.

In this case overall efficiency would be about the same, with the variations being how the pax get to the airport.

I would be more curious to see a Q vs a CRA/J and the E Jets. flying YTZ/YYZ - YOW/YUL.
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HBJZA
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 2:32 pm

Well these datas are from Bombardier but they must be true

http://www.q400.com/q400/en/green2.jsp
 
ytz
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 2:32 pm



Quoting YYZatcboy (Reply 4):
I would be more curious to see a Q vs a CRA/J and the E Jets. flying YTZ/YYZ - YOW/YUL.

I would think that on this point the Q would win out. Given that the structural efficiency would be about the same, I would think that the turboprop would lower per capita fuel consumption.
 
ytz
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 2:33 pm



Quoting HBJZA (Reply 5):
Well these datas are from Bombardier but they must be true

http://www.q400.com/q400/en/green2.jsp

But that compares to an older 70-85 seat jet.
 
tdscanuck
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 2:36 pm



Quoting YYZatcboy (Reply 4):
Both aircraft are efficient more or less equally I would imagine if fully loaded.

I suspect that's not true. The turboprop has an inherent fuel burn advantage, which is layered on top of a lower cruise speed (which means considerably less cruise thrust required). Although the A321 is bigger, I don't think the scaling on the per-seat efficiency is as steep as the engine/cruise speed efficiency change.

But if somebody's got numbers to put to that, I'd love to see 'em (I half-trust Bombardier but they're not exactly a neutral party).

Tom.
 
Cubsrule
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 2:45 pm



Quoting Tdscanuck (Reply 8):
The turboprop has an inherent fuel burn advantage, which is layered on top of a lower cruise speed (which means considerably less cruise thrust required).

It's not really an issue on the routes we're discussing here, but for the sake of completeness - and in the context of a more global discussion - it's worth noting that the lower cruise speed also means that the DH4 will take significantly longer than a jet to cover a 600 or 800 km route, canceling out some of the fuel burn advantage.
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ytz
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 2:47 pm



Quoting Cubsrule (Reply 9):
it's worth noting that the lower cruise speed also means that the DH4 will take significantly longer than a jet to cover a 600 or 800 km route, canceling out some of the fuel burn advantage.

I thought that's why the rule of thumb was 500nm was really the max effective range for a turboprop with most operating around a max of 300nm.
 
ytz
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 2:51 pm

If I understand correctly, it was the fuel efficiency of the Q400 that compelled airlines like BE and QX to deploy these aircraft instead of a CRJ, E-170 or even combine loads and deploy Boeing/Airbus narrowbodies. So wouldn't that same model apply to Porter here?
 
ytz
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 2:58 pm



Quoting YTZ (Reply 12):
airlines like BE

...sorry meant FlyBE
 
Cubsrule
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sat Jul 25, 2009 3:03 pm



Quoting YTZ (Reply 10):
I thought that's why the rule of thumb was 500nm was really the max effective range for a turboprop with most operating around a max of 300nm.

I think so. OTOH, though, the other issue at work is that if an airline has, say, 20 400km route and 5 600 km routes, it's probably more efficient for it to operate all Q400s than a bunch of Q400s and 3 or 4 jets.
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Boeing4ever
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sun Jul 26, 2009 1:36 am



Quoting YTZ (Reply 2):
I understand the aviation business aspect of it. I just happen to be debating some enviro-idealist who detest the Island airport and the Q400 and thinks that for the sake of the environment every Montreal or Ottawa bound passenger should hop on an AC A321....or in his dream world even a B777.

I would say the Q400 is cleaner. A lot of the concepts coming out for new narrowbody aircraft feature propfans or even a return to turbofans on account of fuel burn efficiency.

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prebennorholm
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sun Jul 26, 2009 2:26 am



Quoting Tdscanuck (Reply 8):
The turboprop has an inherent fuel burn advantage, which is layered on top of a lower cruise speed (which means considerably less cruise thrust required).

It's not that simple. At economic cruise all airliners have a drag around 6% of the actual weight. It doesn't matter if it is a turboprop plane or a jet plane, of if going low or high.

Turboprop engines produce more thrust for a given fuel flow.

Turboprop planes don't go very high because it is not possible to make a propeller which is efficient at both sea level and high cruising altitude.

Jet planes take advantage of the ability to cruise at high altitude where they can cruise at a higer speed with the same drag.

Turboprop planes cannot cruise at so high speed. That would make the propeller tips go supersonic, which would degrade fuel effficiency significantly, and make the cabin noise unbearable. (Anyway, modern propeller technology has come a long way and made turboprop planes cruise at impressingly high speed, the Q400 being a good example).

Jet planes spend a lot of fuel to reach their optimal cruising altitude. Turboprop planes reach their optimal cruising altitude much faster, since it is much lower. And the engine produces more thrust for the same fuel flow.

Therefore turboprop planes are more fuel efficient on short routes.

On longer routes, where by far the most time is spent at optimal cruising altitude, the jet and turboprop planes come out rather equal. But the jet plane has the advantage to go faster and more comfortably. Less noise and vibrations, and mostly in less turbulent air.

There is a totally different aspect: If we imagine that tomorrow all planes are turboprop planes, going hardly higher than FL250, then air traffic would at many places go completely to pieces because of lack of air space. The mixture of turboprop planes and jet planes, going efficiently at different altitudes, is what makes present day air traffic possible in high traffic regions.
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7673mech
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sun Jul 26, 2009 4:02 am

What tastes better an apple or an orange???

Seriously, while turboprops maybe a little greener ... the A320 holds more people, so is one A320 flight greener then multiply turbo prop flights???
 
Thule
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sun Jul 26, 2009 6:34 am

Something that a lot of people leave out in emissions debates, especially in multi-passenger vehicles, is whether we should always use emissions per capita as a comparison, rather than total emissions per vehicle.

If everyone in the world had their own hybrid car, then we car owners would all have great per capita gas mileage, but it would be far worse for emissions than if only 1/6 of the population had cars, and they were SUVs.

In the same way, if just one person boycotts flying, at the end of the day, the Dash-8/A320/Jumbo Jet is still going to fly and belch its tons of CO2. If Friday gives you a load factor of 100%, and Tuesday gives you a load factor of 15%, the plane is going still going to burn about the same large amount of fuel. Decisions about the movements of multi-passenger vehicles like planes require the financial votes of large groups of consumers.

What I'm saying is, maybe the question that should be debated isn't which of the two is more fuel efficient, but why there are two aircraft flying the same route to the same city at the same time, when one could do. I know that they're different airports and airlines, and that there's healthy competition going on. I'm just trying to make an observation here.
 
captaink
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Sun Jul 26, 2009 6:48 am



Quoting Prebennorholm (Reply 17):

Turboprop planes cannot cruise at so high speed. That would make the propeller tips go supersonic, which would degrade fuel effficiency significantly, and make the cabin noise unbearable. (Anyway, modern propeller technology has come a long way and made turboprop planes cruise at impressingly high speed, the Q400 being a good example).

Jet planes spend a lot of fuel to reach their optimal cruising altitude. Turboprop planes reach their optimal cruising altitude much faster, since it is much lower. And the engine produces more thrust for the same fuel flow.

Therefore turboprop planes are more fuel efficient on short routes.

On longer routes, where by far the most time is spent at optimal cruising altitude, the jet and turboprop planes come out rather equal. But the jet plane has the advantage to go faster and more comfortably. Less noise and vibrations, and mostly in less turbulent air.

There is a totally different aspect: If we imagine that tomorrow all planes are turboprop planes, going hardly higher than FL250, then air traffic would at many places go completely to pieces because of lack of air space. The mixture of turboprop planes and jet planes, going efficiently at different altitudes, is what makes present day air traffic possible in high traffic regions.

Excellent explanation.

Answering the posters question, on short hops modern turboprops are greener, as they are smaller and burn less fuel. On longer flights, a modern jet is greener because it can cruise at a higher altitude at higher speeds, on such a flight a turboprop chopping air at a lower altitude for a much longer time period would render it far from green.
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Boeing4ever
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Mon Jul 27, 2009 1:01 am

Basically, for the hop you and your friend are arguing about, the turboprop is cleaner. And another enviro-idealist bites the dust.

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ytz
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Tue Jul 28, 2009 11:34 pm



Quoting Boeing4ever (Reply 22):
Basically, for the hop you and your friend are arguing about, the turboprop is cleaner. And another enviro-idealist bites the dust.

That's basically what I thought. I'd imagine that it'd be a bit of a stretch to argue that a Q400 is more efficient than an A319 for Toronto-Halifax. But I was pretty confident that a turboprop would be cleaner on the 300 nm YTZ-YOW, YTZ-YUL sectors. When you consider that AC is going to smaller aircraft like the E-Jets for even some of their trips on these sectors, so that the efficiency of size is diminished, its hard to argue that a Porter Q400 is all that bad for the environment.
 
CRJ900
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Wed Jul 29, 2009 12:14 pm

Norwegian regional carrier Widerøe now flies the Q400 on Bergen-Tromsø-Sandefjord (Torp), both flights are around 1250 km with flight time of around 2hrs30min.

Widerøe claims it is more economical and environmentally friendly to fly such routes than connect through OSL on 737s. Are they correct or are the routes so long that the Q400 becomes fuel inefficient?
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MSNDC9
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Wed Jul 29, 2009 3:20 pm

Real simple. On a 100 mile flight, the prop is better - even if you run two of them. As you approach about 280 miles the tide shifts to the A320. By 350 (closer to 380 for the Q400) miles its over for the prop no matter how you slice it. Passenger demand aside anyway.

That said, if you're running a A320 from Chicago to Kearney Nebraska you need your head examined. And if you're runnig a Q400 from New York to Chicago your probably giving up a ton of potential revenue.
 
rheinwaldner
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Thu Jul 30, 2009 2:41 pm



Quoting 7673mech (Reply 18):



Quoting Thule (Reply 19):

The question is simply about CASM. Other factors are out of scope (per original post).

Quoting Captaink (Reply 21):
Answering the posters question, on short hops modern turboprops are greener, as they are smaller and burn less fuel. On longer flights, a modern jet is greener because it can cruise at a higher altitude at higher speeds, on such a flight a turboprop chopping air at a lower altitude for a much longer time period would render it far from green.

I don't know why only range is stated as criteria. Size has enourmous impact on CASM too. The larger the plane the more efficient. Tdscanuck was the only one who said something about the balance between the two.

IMO turboprops are more efficient but larger planes are more efficient too. Inbetween those factors the question is which delivers lower CASM.

IMO no 70-seater beats a 190-seater in CASM. Bombardier lists roughly a 10% advantage in CASM between the Q400 and a 120-seater jet (let's say a A319 or even a A318). I assume the A321 is more than 10% better in CASM than A319 or A318 -> ergo the A321 has lower CASM than Q400.
 
timz
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Thu Jul 30, 2009 6:59 pm



Quoting Rheinwaldner (Reply 27):
The question is simply about CASM.

"The" question is about fuel use per seat-- the original poster said nothing about other costs.

You'd think that would be a simple enough question to answer-- on a 300 nm trip, picking reasonable values for the other necessary assumptions, how much fuel per seat does each aircraft burn? But such answers are rare, here and elsewhere.
 
ytz
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RE: Q400 Vs. A320/A321 - What's More Fuel Efficient?

Thu Jul 30, 2009 11:12 pm



Quoting Timz (Reply 28):
- the original poster said nothing about other costs.

Correct. I was wondering about fuel consumption not CASM. Of course, CASM improves dramatically as you grow the airplane. But does fuel consumption improve that dramatically as well? I am skeptical that's the case for anything less than 500nm.

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