Rabenschlag From Germany, joined Oct 2000, 757 posts, RR: 0 Posted (8 years 11 months 2 weeks 5 days 6 hours ago) and read 375 times:
There has been great discussion regarding the the performance of A343 and A342. Finally I am convinced that these AC are underpowered indeed. Apparently, some airlines are getting rid of ther A343's because of insufficient TO-performance and cruising speed.
What amazes me: Why cant AI solve the problem by installing more powerful engines in future A343 or 342 as they do in the 345 346? Why didnt AI recognise the problem much faster? Does anybody know if they tried or intended to solve it?
Steman From Germany, joined Aug 2000, 1171 posts, RR: 11 Reply 3, posted (8 years 11 months 2 weeks 5 days 6 hours ago) and read 342 times:
Hi,
if AI would offer a different engine for its A340 "Classic" they could choose among many engines: PW 2000series, RR RB.211-535series, uprated CFM56 or downrated Trent500 or PW4056.
Of all this option the most viable in my opinion is the uprated CFM56 because of low costs and because the A340 doesn't really need a more powerful engine.
Anyway, is there a significant difference in cruising speed between the A330 and the A343? If the main cause of the lower cruise spedd of the A340 is its powerplants then the A330 should be as fast as Boeing jetliners.
Skystar From Australia, joined Jan 2000, 1363 posts, RR: 3 Reply 4, posted (8 years 11 months 2 weeks 5 days 5 hours ago) and read 330 times:
As far as I know (from a very trusted source), the actual optimum cruise speed for the 330/340 is M0.805 (although in practise M0.82 is used).
Cruise is largely a function of wing design. A340 & the A330 share the same wing. Wing sweepback of 30°, the A32x has a sweepback of 25°. B747 has a sweepback of 37° and the A340NG will have a sweepback of 31° (IIRC for the NG).
Stefano, you raise a good point. For all the stalwarts of the "Airbus A340 is too slow and has no power", I think the proof is in the pudding. If the 340 were more powerful, we have a perfect example of what that would be. The A330.
I think the 340's engines are at their upper power range, IIRC, SQ was having engine problems with their -300Es initiatially. A 5% thrust bump is available on the -300E for a limited time. CFM would have to develop more powerful CFM56s naturally. Actually, an upgraded A340 classic is planned, with improved CFMs & avionics (LCD displays, etc.)
My friend, a CX 340/330 Captain has no real problem with the 340. Admittedly its no 757, but he says, "It fulfills its intended role very economically".
TEDSKI From , joined Dec 1969, posts, RR: Reply 5, posted (8 years 11 months 2 weeks 5 days 5 hours ago) and read 321 times:
I agree that Airbus should replace those underpowered CFM56-5 engines on the A340-200/300 with either the P&W 2000 series or RR RB211 series used on the Boeing 757 that have over 40,000lbs thrust.
Gerardo From Switzerland, joined May 2000, 3479 posts, RR: 47 Reply 6, posted (8 years 11 months 2 weeks 5 days 4 hours ago) and read 317 times:
Why should the A343 have more thrust? To allow spotters like us to take pictures of A340 with a bigger angle of attack?
As for a possible engine choice: I mentioned only the RR Trent 500 derivative, because that would offer a family of A340-300/-500/-600. The -200 is out of the market. It hasn't been ordered since a few years now.
Of course, RR doesn't have an exclusive agreement, as for example GE on the B777X. THis could mean, that perhaps GE or PW, or even GP (the joint venture of GE and PW) could make a step forward and offer this solution.
Regards
Gerardo
dominguez(dash)online(dot)ch ... Pushing the limits of my equipment
TEDSKI From , joined Dec 1969, posts, RR: Reply 7, posted (8 years 11 months 2 weeks 5 days 2 hours ago) and read 305 times:
On the A340-200/300, the RR Trent 500 would be too heavy for the wings to support 4 of them. Like I said earlier, the P&W 2000 series that is used on the Russian IL-96M or the RR RB211 version used on the 757 would be better.
Sndp From Belgium, joined Feb 2000, 553 posts, RR: 3 Reply 8, posted (8 years 11 months 2 weeks 5 days 2 hours ago) and read 305 times:
At Farnbourough Airshow Airbus announced the enhanced A340 with imporved CFM engines, which will lower maintenance cost and boost on wing time and I thought which will also improve power. BUT please stop thinking that we all know it better than the engineers at Airbus. The A340 is, like mentioned by a few other poeple, like it is (you can call it underpowered if you want) because the current configuration makes it a very fuel efficient airplane. It is perfect for its operations. Look at Lufthansa, how happy they are with their A340s ordering more and more of them, and LH makes great profits. So, stop saying that this aircraft is underpowered, please. A big angle of attack at take-off was not what it was built for. As it was stated before, the A340 flies to cruise altitude just a few minutes slower than the B747, so what? Should you give in fuel efficiency for this matter?
sndp
Rabenschlag From Germany, joined Oct 2000, 757 posts, RR: 0 Reply 9, posted (8 years 11 months 2 weeks 5 days ago) and read 283 times:
Is it true that a 777 200/300 is about 20% more efficient in terms of seat-mile costs? I remember to haver read these figueres in an issue of FLUG REVUE. This, by the way, at .86 mach.
If this was true - why do we all think that the A340 is economically optimised instead of optimised for maximum performance? Wouldnt that mean that it isnt optimised at all (besides looks perhaps)?
Joni From , joined Dec 1969, posts, RR: Reply 10, posted (8 years 11 months 2 weeks 4 days 22 hours ago) and read 269 times:
Counting seat-mile costs is known to be rather difficult for Boeing and Airbus, particularly if the results wind up in brochures I saw a 777 brochure that had manufactured high seat-mile costs for 346 by decreasing the number of seats on the plane.
Rumour does have it that 777 costs less to maintain and 343 burns less fuel.
Incidentally, Airbus does plan to offer an "A343 Enhanced" (there is a press release available to this effect) that has modified engines, wing and various cockpit and interior perks from the 345/346 program.
TEDSKI From , joined Dec 1969, posts, RR: Reply 11, posted (8 years 11 months 2 weeks 4 days 22 hours ago) and read 260 times:
If Airbus must stick with the CFM56 on this new Enhanced A340-300, why not install water injection like they did on the early model USAF KC-135A air refueling tankers with P&W J57 turbojets for the extra takeoff power needed when carrying a full load of passengers, fuel and cargo?
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From Germany, joined Oct 2000, 757 posts, 
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I saw a 777 brochure that had manufactured high seat-mile costs for 346 by decreasing the number of seats on the plane.
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