Why are Airbus Heavier than Boeing
Joined: Jan 2006
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From: EU
The picture is a fake... look at all the smoke in photoshop, it's the same color. Also look closely at the lines of color below the wheel that touches the ground. They are very much in-line while all other colors of the runway has pixels in them... this is the work of the blur tool in photoshop...
Bear Behind
Joined: Dec 2001
Posts: 352
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From: Canadia, the French bit
Oh good grief, if you think that's a genuine photo you really shouldn't be perusing a professional aviation website.
Now then, may I try to answer a few of these questions? I'm not saying one is right or wrong, what I'm saying is that soem of the differences in weight come from the design philosophy.
The A320 has a larger engine fan diameter than the 737 (any denomination) even though, nominally, they have the same CFM56 engines (the core of the -5 on the A320 is the same as the core on the -7 of the 737NG. The cores are the same, the fans aren't). Why is the fan diameter greater? Well, the -5 engine on the A320 has a higher bypass ratio than the -7 on the 737. That has 2 benefits - 1) the A320 engine has a lower specific fuel consumption and 2) the A320 engine runs cooler and so stays on the wing longer (greater EGT margin) which gives lower engine maintenance costs. So the A320 engines burn less fuel than the 737 engines and should cost less to maintain. The penalty is that the A320 needs a taller landing gear for ground clearance of the engines, so the gear is heavier than a 737 (weight penalty). The A320 has a greater fuselage diameter than the 737, so it will necessarily have more metal in it. It also has main landing gear doors to try to improve the aerodynamics (but they weigh something, of course) whereas the 737 wheels and wheel hubs sit partially in the airflow, so you get parisitic drag.
What you need to realise is that weight is not the be all and end all. The A320 is heavier than the 737. But the A320 engines burn less fuel and the aerodynamics are slightly better (yes the 737NG had a new wing, but Boeing were limited by the interface with the fuselage, as it didn't change, so they were forced to compromise by the constraints imposed on the spar positioning).
Swings and roundabouts that, at the end of the day, mean that they are both very close in fuel burn - and that's what counts these days.
I hope that's quite clear. And the company I work for has the A320 (and A319).
p-k-b
Now then, may I try to answer a few of these questions? I'm not saying one is right or wrong, what I'm saying is that soem of the differences in weight come from the design philosophy.
The A320 has a larger engine fan diameter than the 737 (any denomination) even though, nominally, they have the same CFM56 engines (the core of the -5 on the A320 is the same as the core on the -7 of the 737NG. The cores are the same, the fans aren't). Why is the fan diameter greater? Well, the -5 engine on the A320 has a higher bypass ratio than the -7 on the 737. That has 2 benefits - 1) the A320 engine has a lower specific fuel consumption and 2) the A320 engine runs cooler and so stays on the wing longer (greater EGT margin) which gives lower engine maintenance costs. So the A320 engines burn less fuel than the 737 engines and should cost less to maintain. The penalty is that the A320 needs a taller landing gear for ground clearance of the engines, so the gear is heavier than a 737 (weight penalty). The A320 has a greater fuselage diameter than the 737, so it will necessarily have more metal in it. It also has main landing gear doors to try to improve the aerodynamics (but they weigh something, of course) whereas the 737 wheels and wheel hubs sit partially in the airflow, so you get parisitic drag.
What you need to realise is that weight is not the be all and end all. The A320 is heavier than the 737. But the A320 engines burn less fuel and the aerodynamics are slightly better (yes the 737NG had a new wing, but Boeing were limited by the interface with the fuselage, as it didn't change, so they were forced to compromise by the constraints imposed on the spar positioning).
Swings and roundabouts that, at the end of the day, mean that they are both very close in fuel burn - and that's what counts these days.
I hope that's quite clear. And the company I work for has the A320 (and A319).
p-k-b
Joined: Dec 2000
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From: on the golf course (Covid permitting)
pkb
Useful background technical information, but it doesn't account for a 12 tonne (25%) weight difference, IMHO.
Could this unresolved weight difference maybe go some way to explaining the (apparent) large weight problems Airbus have with the A380? ... and yes, I know that all new aircraft are overweight by a margin suring development.
Useful background technical information, but it doesn't account for a 12 tonne (25%) weight difference, IMHO.
Could this unresolved weight difference maybe go some way to explaining the (apparent) large weight problems Airbus have with the A380? ... and yes, I know that all new aircraft are overweight by a margin suring development.
Joined: Nov 2000
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Remember all the other little extras like triple ADIRU, Brake Cooling fans, even heated foot pedals, etc. The options list for an Airbus is huge.
Apart from selecting HUD, different manufacturers for brakes, KGS or LBS for weights, max take off weights and thrust settings for the engines there isn't much to select in the way of additional kit with a 737NG unless you want a BBJ...
Apart from selecting HUD, different manufacturers for brakes, KGS or LBS for weights, max take off weights and thrust settings for the engines there isn't much to select in the way of additional kit with a 737NG unless you want a BBJ...
Bear Behind
Joined: Dec 2001
Posts: 352
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From: Canadia, the French bit
TopBunk
12 Tonne?
What?
Look at Flip Flop Flyer's post. Difference between an A320 and a 737-800 is of the order of 1 tonne. Where on earth does 12 tonnes come from? No way in hell!
I just dug out Boeing's estimates from when they wanted re-equip our fleet, and Airbus' estimates.
A320 OEW 43759kg
737-800 OEW 42829kg (without winglets, by the way - the gap closes when winglets are added).
Again, about 1 tonne difference, nowhere near the 12 tonnes you mentioned! Where on earth did you get that figure from?
p-k-b
12 Tonne?
What?
Look at Flip Flop Flyer's post. Difference between an A320 and a 737-800 is of the order of 1 tonne. Where on earth does 12 tonnes come from? No way in hell!
I just dug out Boeing's estimates from when they wanted re-equip our fleet, and Airbus' estimates.
A320 OEW 43759kg
737-800 OEW 42829kg (without winglets, by the way - the gap closes when winglets are added).
Again, about 1 tonne difference, nowhere near the 12 tonnes you mentioned! Where on earth did you get that figure from?
p-k-b
Bear Behind
Joined: Dec 2001
Posts: 352
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From: Canadia, the French bit
But in terms of performance, those 2 machines don't really compare, do they? They have roughly the same seating capacity (737-400 a little smaller). But the A320 offers substantially more range because it has a much bigger (more efficient) wing with much bigger fuel tanks contained therein. The 3000nm range criteria set for the A320 means that the bigger wing is necessary to accommodate the required fuel and I'm sure that's where you'll find the bulk of that weight difference that you quote - in the much bigger wing.
That along with, of course, the fuselage which is both longer (slightly) and wider (slightly). That adds up to quite a lot more metal in the fuselage as well.
p-k-b
That along with, of course, the fuselage which is both longer (slightly) and wider (slightly). That adds up to quite a lot more metal in the fuselage as well.
p-k-b
