David_itl From United Kingdom, joined Jun 2001, 7360 posts, RR: 14
Reply 3, posted (11 years 11 months 9 hours ago) and read 7987 times:
Can I allege that there might not have been a big load of passengers? One of the services in the middle of June had a whopping 58 passengers on board. I do hope that the service has become more popular.
MD88Captain From United States of America, joined Nov 2001, 1330 posts, RR: 20
Reply 4, posted (11 years 11 months 9 hours ago) and read 8003 times:
GKirk. Your picture proves nothing. Not a thing. Even a 727 will leap off the ground when it is lightedly loaded. The 340 is a slow climber and eats up tons of runway during takeoff. This is just a characteristic of the airplane. It doesn't mean it is a bad airplane. It obviously fits the needs of many airlines. I think it is similar to the venerable 727. Underpowered, but with many other redeeming qualities.
Sllevin From United States of America, joined Jan 2002, 3376 posts, RR: 6
Reply 11, posted (11 years 11 months 8 hours ago) and read 7912 times:
All four-engined aircraft are going to have inferior climb performance compared to twinjets, for the simple reason that they EXIST to have a worse power-weight ratio.
All aircraft are certified and operated on the assumption that they will lose an engine. In a twinjet, this means you lose 50% of your thrust, and all remaining thrust is asymetrical. So when you *don't* lose an engine you have lots of power available.
In a four engine aircraft, losing an engine means only losing 25% thrust and half the thrust on one side. That's significantly more engine-out performance; therefore, a four engined aircraft can take off significantly heavier even if the net thrust with all four engines working is the same.
TEDSKI From , joined Dec 1969, posts, RR:
Reply 12, posted (11 years 11 months 5 hours ago) and read 7797 times:
This past Sunday I was on a World Airways MD-11 that was fully loaded, and this thing with three 62,000lb thrust PW4000 series engines had a fast takeoff roll and lifted off the runway very quickly with the same angle as the A340-300 in the picture, and reached cruising altitude within a few minutes. The A340-300 needs engines with thrust of around 40,000lbs to help it climb better.
EssentialPowr From United States of America, joined Sep 2000, 1820 posts, RR: 2
Reply 14, posted (11 years 11 months 4 hours ago) and read 7785 times:
Instead of arguing, why not provide some simple thrust to weight ratios?
From the web page, I selected the heaviest version of each type along w/ the max thrust option for that subtype...
MGTOW 804700 lbs; 4 Trent 553s at 53k thrust ea = .2635
MGTOW 608300 lbs; 4 CFM 56 at 34k thrust ea = .2236
MGTOW 606300 lbs; 4 CFM 56 at 34k thrust ea = .2243
MGTOW 875000 lbs; 4 P&W 4063s at 63.3k thrust ea = .2894
MGTOW 48500 lbs; 2 A3007 at 7.4k thrust ea = .3052
MGTOW 255000 lbs; 2 P&W 2040s at 40.1k thrust ea = .3145
Climb performance is a function of excess thrust. The A340-300 has the lowest thrust to weight ratio in the A340 family. The A340 family in particular has low thrust loadings in comparison to other contemporary jet transports. The A340-300 is a poor climber, and the numbers reflect this. And has been stated, if one watches enough takeoffs, the A340's poorer climb performance is visually apparent.
Skystar From Australia, joined Jan 2000, 1363 posts, RR: 3
Reply 17, posted (11 years 10 months 4 weeks 1 day 20 hours ago) and read 7684 times:
Tedski wrote that a full MD-11 reached cruising altitude within a few minutes. A few minute is about 3 to 4 minutes. Given a typical lowerish cruising altitude of FL310, that means you'd be climbing at almost 8000fpm - sorry credibility goes on this one.
Not bloody possible in my books, empty plane or full one.
You're generally right, but there are a few exceptions - eg. compare the 346 with a few 332s and some 777s.
Also remember that the climb performance of a quadjet is superior to that of a twin in an engine out situation - it has to be:
LMP737 From , joined Dec 1969, posts, RR:
Reply 18, posted (11 years 10 months 4 weeks 1 day 20 hours ago) and read 7656 times:
There was an article about Singapore Airlines fleet plans a couple of years ago in AV Week. In the article it was mentioned that a 777 leaving the same as a A340 on the Singapore-London route will arrive 30 minutes earlier.
RayChuang From United States of America, joined Jun 2000, 7985 posts, RR: 5
Reply 21, posted (11 years 10 months 4 weeks 1 day 17 hours ago) and read 7651 times:
I've seen AF and SQ A340-300's take off from Runway 28R at SFO.
Talk about a runway hogger and slow climber! The A343's from what I saw use as much runway as a 747-400 on the takeoff roll and the climb rate is definitely leisurely compared against even a full-loaded 744 after takeoff. Small wonder why SQ pilots expressed concern about the A343 being unable to dodge the poor weather over the Bay of Bengal on flights to Europe from SIN.
KaiTakFan From United States of America, joined Oct 1999, 1588 posts, RR: 6
Reply 22, posted (11 years 10 months 4 weeks 1 day 15 hours ago) and read 7643 times:
EssentialPowr,Thank you for actually making an intelligent post and using the mathematical facts instead of opinions. Nothing more needs to be said. The facts have been layed out. Opinions are useless in this discussion. Its a shame there wasn't a pic of the 747-400 I was on going from ORD-HKG. Pretty damn heavy load, hot day in Chicago. The take off roll pushed a minute long and we were slow to get alt. If people see this take place then can it be said the 747-400 is now under powered? I think not! Atmopsherical conditions and weights can work wonders in cases like this. A steep climb out pic compared to facts... I wonder who is correct here?!?
TEDSKI From , joined Dec 1969, posts, RR:
Reply 23, posted (11 years 10 months 4 weeks 3 hours ago) and read 7461 times:
I didn't keep track of the time the MD-11 took to reach it's cruising altitude, so I shouldn't have said in a few minutes, but it was quick with the power the three PW4000 series engines had of 62,000lbs. This aircraft was not a slow climber.