Real A300, 310, 757, 767 replacement aircraft idea
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Thing is open rotors are heavy too, as is the structure keeping them in place.
Still : a fuel consumption reduction of >20% make OEMS look again (Snecma, RR).
No doubt they are aiming for a 20-30 klbs familiy for the next generation NB.
I think most studies from Boeing and Europe move the engines up the aft fuselage for that reason.
Going to 3 engines, 2 wingmounted and 1 in tail like Tristar and DC10, would keep the CoG under control - only 1/3 of engines in tail - and it would keep the underwing engine size within reasonable limits.
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But this brings back the CoG problems of aft engines, which the weight of extreme bypass engine only makes worse.
The moment the rudder / vertical stabalizer has to create for longitudal stability / control would be high requiring a large control surface. On the other hand a B2 can do it too. There are smart multi control solutions.
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I´m not sure if I see the center of gravity issue in relation to high BPR engines. The position of the wing is adjusted to make it right.
For a plane which rotates on takeoff, the CoG and wing have to be in a narrow range, slightly ahead of the main gear. If the CoG is too far back, the plane tips on tail. If the CoG is too far forward, the plane will not rotate despite elevator downforce.
If the engines are mounted on the wing, they are near the CoG. The fuel is in the wing as well. The tail and nose are balanced between each other. The big variable is the payload, but since there is a significant amount of fuselage volume both ahead and behind the wing, those tend to balance as well.
Now if you place the engines in the tail, you have to counterbalance them by bringing the wing and main gear backwards. You have long front fuselage trying to counterbalance short rear fuselage and engines.
Except that now, most of your payload volume is ahead of the wing. Which means that yout plane is liable to fall on the tail when the payload is small or absent. Il-62, VC-10, B-727... there are incidents falling on the tail on ground, needing tail supports to avoid this, asking passengers to disembark tail first...
Keesje,
We have done a study on the A321-200 vs. the B757-200W. The payload range capabilities of the 75W far exceeds the A321. It is basically useless beyond 5-5.5 hrs whereas the 757 will take a 20 ton payload and full tanks of fuel, giving it a range of about 8 hours.
We have done a study on the A321-200 vs. the B757-200W. The payload range capabilities of the 75W far exceeds the A321. It is basically useless beyond 5-5.5 hrs whereas the 757 will take a 20 ton payload and full tanks of fuel, giving it a range of about 8 hours.
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True, the A321 is useless (& not designed / used) for longer ranges like transatlantic. It is however 13 tons lighterthen the 757 & much more fuel efficient for anything shorter then 5 hours.
It is also more comfortable (wider cabin), 100% competible with widely used A320 and A319, can carry cargo containers & pallets but most importantly : it is for sale.
Coincidently I found this oldish picture today, it shows the situation. Marking the places for the Greenliner, LRJ and Ecoliner like new aircraft designs.
The A300/A310/767-200/757-200/757-300 leave a big replacement market in the B737-900ER/A321 - B787-8/A330-200 gab.
It is also more comfortable (wider cabin), 100% competible with widely used A320 and A319, can carry cargo containers & pallets but most importantly : it is for sale.
Coincidently I found this oldish picture today, it shows the situation. Marking the places for the Greenliner, LRJ and Ecoliner like new aircraft designs.
The A300/A310/767-200/757-200/757-300 leave a big replacement market in the B737-900ER/A321 - B787-8/A330-200 gab.
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True, the A321 is useless (& not designed / used) for longer ranges like transatlantic. It is however 13 tons lighterthen the 757 & much more fuel efficient for anything shorter then 5 hours.
It is also more comfortable (wider cabin), 100% competible with widely used A320 and A319, can carry cargo containers & pallets but most importantly : it is for sale.
It is also more comfortable (wider cabin), 100% competible with widely used A320 and A319, can carry cargo containers & pallets but most importantly : it is for sale.
What about Airbus 322/323? With new, bigger wing and engines, but keeping otherwise a heavy commonality with 321? The plane would get heavier and less efficient on short range, but it would gain range.
Consider the big narrowbodies:
Boeing 737-900: maximum 189 seats, MTOW 79 tons
Airbus 321: maximum 220 seats, MTOW 93 tons, OEW 48 tons.
Boeing 757-200: maximum 239 seats, MTOW 115 tons, OEW 58 tons.
Tu-204-200/Tu-214: maximum 212 seats, MTOW 110 tons, OEW 59 tons. An advantage over B757 is that Tu-204 is for sale!
DC-8-63: maximum 259 seats, MTOW 158 tons, OEW 70 tons.
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Airbus A320 Enhanced Performance Study April 2006
What about Airbus 322/323? With new, bigger wing and engines, but keeping otherwise a heavy commonality with 321? The plane would get heavier and less efficient on short range, but it would gain range.
The A321 is significantly longer then the A320. Something inbetween would offer growth for A320 customers. An A320.5 ..
As you suggested it had improved wings, engines, cabin etc. Funny thing is a few months later Airbus announced the A320 Enhanced. So it probably was a logical evolution.
Henry Lam created a nice artist impression. It also had rooftop windows offering a nice natural light in the cabin, enabling every passenger to see the blue sky..
http://www.airliners.net/discussions...d.main/2724857
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It also had rooftop windows offering a nice natural light in the cabin, enabling every passenger to see the blue sky..
Start with bringing back DC-8 windows. 36X46 cm. Biggest ever on pressurized jetliner - all the bigger windows have been on wholly unpressurized planes or slightly pressurized low-flying propeller planes like Vickers Viscount. Even 787, if it ever flies, has windows that are mere 28 cm wide.
With IFE being a big part of long-haul these days the roof top windows would seem surpurfolous.
On Emirates they shut all the window blinds in the cabin so the punters can sleep or see their 1000 channels clearly on the LCD screen.
Like your ideas though - very well thought out.
halas
On Emirates they shut all the window blinds in the cabin so the punters can sleep or see their 1000 channels clearly on the LCD screen.
Like your ideas though - very well thought out.
halas
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Keesje I am certain your post here has set off some ideas at the Boeing and Airbus marketing departments. You may not be bang on with all your thinking but it is a good effort and you should welcome the constructive debate here.
On this note I honestly wonder if a carbonfibre fuselage can withstand the repetitive stress of short haul cycles and so many landings ?
Long haul airliners get high hours but low cycles. The Dreamliner wouldn't fill that gap so you've definitely identified a future gap in the market... cheers.
But... an aircraft designed for long range, is so efficient in short hops?
Long haul airliners get high hours but low cycles. The Dreamliner wouldn't fill that gap so you've definitely identified a future gap in the market... cheers.
