Reggaebird From Jamaica, joined Nov 1999, 1169 posts, RR: 0 Posted (3 years 6 months 3 weeks 1 day 19 hours ago) and read 14964 times:
I recently observed two Emirates A380s departing Sydney airport and noticed that the initial climb angle seemed less steep than other aircraft. I then flew on an Emirates A380 out of Auckland and got the distinct sensation of a lower climb angle than when I fly on other aircraft. Is the lower angle a reality? Is it a design feature? If so, what benefit does it provide?
Here are videos of the two Sydney departures that I mentioned:
Affirmative From France, joined Jul 2009, 308 posts, RR: 0 Reply 3, posted (3 years 6 months 3 weeks 1 day 17 hours ago) and read 14735 times:
I'm not sure if I agree.. I've seen the A380 taking off from DXB now a couple of times and compared to EK 744 cargo I'd say it's pretty much the same. The A380 seem to have a higher initial pitch (AOA) on rotation but once it settles they seem to have pretty much the same as the 744.. The rate of climb on the other hand is way better than the 744, quite similar to the A332 actually..
I know the 744 tends to look like it has a higher AOA because of the hump but from my experience you can't spot the difference, maybe if you had them taking off side by side.
Khobar From United States of America, joined Mar 2006, 2379 posts, RR: 4 Reply 4, posted (3 years 6 months 3 weeks 1 day 17 hours ago) and read 14674 times:
One of the reasons the A380 has a smaller noise footprint than the 747 is because it can outclimb the 747. Of course it also has larger, slower turning fans which also contributes to its smaller noise footprint.
Khobar From United States of America, joined Mar 2006, 2379 posts, RR: 4 Reply 6, posted (3 years 6 months 3 weeks 1 day 14 hours ago) and read 14257 times:
Quoting Scbriml (Reply 5): It's certainly not a limitation of the plane:
SimProgrammer From France, joined Aug 2004, 180 posts, RR: 0 Reply 7, posted (3 years 6 months 3 weeks 1 day 9 hours ago) and read 13910 times:
The A34x is also a slow climber when full, becasue the wing design is optimised for cruise economy. The airshow 380 is an empty plane & very easy to do at low alt.
7673mech From United States of America, joined Mar 2004, 632 posts, RR: 0 Reply 9, posted (3 years 6 months 3 weeks 1 day 8 hours ago) and read 13560 times:
Quoting Scbriml (Reply 5): It's certainly not a limitation of the plane:
Cpd From Australia, joined Jun 2008, 4879 posts, RR: 44 Reply 11, posted (3 years 6 months 3 weeks 1 day 6 hours ago) and read 12613 times:
Quoting Ogre727 (Reply 10): I flew it from SIN to LHR... it struck me as a very slow climber....
I think they often run reduced power take-offs, at least out of Sydney - the near silence suggests that.
But, you definitely know when they use more power - the noise is much louder and very distinctive (Trent 900 anyway - I can pick it immediately from any other plane just by the sound). That's all quite unscientific, but I see 2 or 3 A380's just about every day, so you get to know them well enough.
9MMPD From Australia, joined Oct 2005, 262 posts, RR: 1 Reply 12, posted (3 years 6 months 3 weeks 1 day 4 hours ago) and read 11455 times:
Both my A380 flights (SIN - LHR - SIN) felt like they had a shallow climb. What also led to this feeling was how quiet the cabin as during departure maybe that has something to do with it?
Vikkyvik From United States of America, joined Jul 2003, 8225 posts, RR: 28 Reply 13, posted (3 years 6 months 3 weeks 1 day 3 hours ago) and read 11210 times:
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Quoting Reggaebird (Reply 2): Quoting Cloudyapple (Reply 1):
Are you referring to the angle of attack of the aircraft or the rate of climb of the aircraft?
I am referring to the angle of attack on departure.
Not to be nitpicky ( ), but you can't tell the angle of attack of an airplane just from watching it fly by. Angle of attack refers to the angle of the wing relative to the freestream flow.
"Two and a Half Men" was filmed in front of a live ostrich.
Astuteman From United Kingdom, joined Jan 2005, 9139 posts, RR: 96 Reply 16, posted (3 years 6 months 3 weeks 1 day 2 hours ago) and read 10770 times:
Quoting Reggaebird (Thread starter): I then flew on an Emirates A380 out of Auckland and got the distinct sensation of a lower climb angle than when I fly on other aircraft
Whether the angle-of-attack is any different, I don't know, but that HUGE wing generates a phenomenal amount of lift - enough in fact to give a 600 tonne to 625 tonne A380 variant (if there ever is one), decent field and climb performance.
Hence the "cooking" 560 tonners we have today have an abundance of lift, even at MTOW.
So they will have absolutely no problem whatsoever gaining altitude in a VERY timely manner
Quoting Affirmative (Reply 3): The rate of climb on the other hand is way better than the 744, quite similar to the A332 actually..
413x3 From United States of America, joined Jul 2008, 1983 posts, RR: 0 Reply 17, posted (3 years 6 months 3 weeks 1 day 2 hours ago) and read 10718 times:
I am sure the slower climb has more to do with fuel savings with such a heavy load on board than any missing power it may or may not have.
Astuteman From United Kingdom, joined Jan 2005, 9139 posts, RR: 96 Reply 18, posted (3 years 6 months 3 weeks 1 day 2 hours ago) and read 10672 times:
Quoting 413x3 (Reply 17): I am sure the slower climb has more to do with fuel savings with such a heavy load on board than any missing power it may or may not have.
Slower thatn it's capable of? Or slower than other planes?
It isn't
Quoting Affirmative (Reply 3): The rate of climb on the other hand is way better than the 744, quite similar to the A332 actually..
Funnily enough, when you look at the field performance charts, if I read them right, the only other widebody that matches the A380 for take-off distance capability is the A330 - according to their charts, these planes will take off at MTOW, at 0 ft and ISA +15c in 2 900m (for comparison, the 773ER chart shows 3 100m for the same evolution..)
Francoflier From France, joined Oct 2001, 3196 posts, RR: 10 Reply 19, posted (3 years 6 months 3 weeks 1 day 2 hours ago) and read 10631 times:
Quoting Swallow (Reply 15): I've read on this board that the 380 can go straight to cruise altitude without having to do a "step climb".
There is no single cruise altitude that an airliner will always climb to on every flight.
Optimum cruise altitude depends on the weight of the aircraft and atmospheric conditions and changes as the aircraft gets lighter.
What the A380 can probably do better than other very heavy aircrafts is climb to a higher cruise altitude earlier in the cruise, probably maintaining a faster rate of climb throughout.
This is due to its huge wing (designed for a much heavier aircraft still) and power to weight ratio.
A maxed out 744 will typically climb to an initial optimum cruise altitude of 30,000 ft, while an A380 can probably go higher under the same conditions, although I don't know how much higher. It will still do step climbs further on after it loses some weight.
Climbing higher sooner has a few advantages. The longer you stay higher, the less fuel you burn, and by being able to go higher sooner you can avoid having to fight for flight levels and get your optimum FL more easily.
Looks like I picked the wrong week to quit posting...
Having been involved in the hot weather trials (and also taking photos at that same airshow), I can assure you that even at high gross weights the A380 can climb really well...
Joakims From Sweden, joined Jan 2002, 55 posts, RR: 0 Reply 21, posted (3 years 6 months 3 weeks 21 hours ago) and read 8807 times:
Quoting Swallow (Reply 14): I've read on this board that the 380 can go straight to cruise altitude without having to do a "step climb".
I remember then my wife and I flew SQ A380 from LHR to SIN. We went up to 35.000 feet directly after takeoff The last climb up to 38.000-39.000 came near Nicobar and Andaman Islands in the Bay of Bengal. I think it was due to the usual turbulence in that area.
Rcair1 From United States of America, joined Oct 2009, 927 posts, RR: 25 Reply 22, posted (3 years 6 months 3 weeks 17 hours ago) and read 7539 times:
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Quoting Francoflier (Reply 19): This is due to its huge wing (designed for a much heavier aircraft still) and power to weight ratio.
I've seen references to the "huge" wing and high power/weight ratio and similar statements several times. Does this mean the wing loading on an A380 is less than typical airliners? I thought that (in basic aeronautical engineering classes I took 20+ years ago) that a lightly loaded wing meant good climb performance, long glide performance, but typically less efficient cruise due to more drag. Or am I remembering wrong (or simplifying too much)? If that is true, then the only reason the A380 would have an unusually light wing load is so that they can build heavier variants. Is that the plan at Airbus? If heavier variants were built - they'd have to be cargo, I have a hard time seeing even larger passenger loads.
It seems quite inefficient to build higher performance into the product than needed, (as an engineer, we try to walk the line), but Airbus is hardly into building inefficient products - and the A380 is reportedly quite efficient - so there must be a reason. The 747 was overbuilt in several regards, but it was the first 'jumbo' (Boeing was somewhat conservative in the design) and built when engineering design/tolerance management was less efficient. I'd expect newer types (regardless of manf) to be closer to optimal.
I guess I'm confused. There must be a reason for oversized wings/power. What is it?
Vikkyvik From United States of America, joined Jul 2003, 8225 posts, RR: 28 Reply 23, posted (3 years 6 months 3 weeks 14 hours ago) and read 7404 times:
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Quoting Rcair1 (Reply 22): I thought that (in basic aeronautical engineering classes I took 20+ years ago) that a lightly loaded wing meant good climb performance, long glide performance, but typically less efficient cruise due to more drag. Or am I remembering wrong (or simplifying too much)?
A lightly-loaded wing should result in less drag than a heavily-loaded wing, all other things being equal. Your induced drag would be reduced.
In general, climb performance is determined by excess thrust.
"Two and a Half Men" was filmed in front of a live ostrich.
Rcair1 From United States of America, joined Oct 2009, 927 posts, RR: 25 Reply 24, posted (3 years 6 months 3 weeks 12 hours ago) and read 7365 times:
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Quoting Vikkyvik (Reply 23): A lightly-loaded wing should result in less drag than a heavily-loaded wing, all other things being equal. Your induced drag would be reduced.
Thanks. I was thinking that the larger wing will cause more parasitic (form) drag - but now that I think about it - what a larger wing will do is cause the induced drag curve to shift down and/or left vs airspeed, and the parasitic curve will move up and/or left - so what changes is the airspeed at which minimum drag is achieved will change, but that does not inherently make the wing/plane less efficient, perhaps a little slower at minimum drag.... I'm sure this is way over simplified.
Quoting Vikkyvik (Reply 23): In general, climb performance is determined by excess thrust.
Duh I knew that.... Stupid question.
rcair1
25 Astuteman: The A380's wing is designed to entertain MTOW's in the 625t - 630t region, to support both ULR A380-800 variants and stretch versions. As for drag, t
26 Starlionblue: As others have said, no you're not. There is no way to tell the angle of attack, which is the angle between the wing and the airflow, from looking at
29 A380900: Also, the big wing has a strategic component: they wanted to completely corner the VLA market. With the big wing, they're telling Boeing: "There's no
30 Francoflier: Interestingly, that would bring its wing loading figure almost exactly to that of the 747-400. That could also be because the A380 maintains a shallo
31 BlatantEcho: Flew LAX-SYD last week on the A380. We took off and climbed up to 32000, then stepped up to 360 and ended up at 390 a few hours out of SYD. Seemed lik
32 Faro: And it looks it. The wing is huge in proportion to the fuselage, which doesn't help the A380's aesthetics much either, but that's a shortcoming airli
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I knew that.... Stupid question.
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