N1120A From United States of America, joined Dec 2003, 29373 posts, RR: 73
Reply 10, posted (11 years 2 months 3 weeks 1 day 4 hours ago) and read 9174 times:
Quoting DeltaMD11 (Reply 9): Might I ask how so? The winglets do not offer any power/thrust advantage to the aircraft. Granted drag is decreased but that is only realized at higher speeds during cruise.
Winglets also improve lift, that is one of the main reasons they have been popular on the 737
Mangeons les French fries, mais surtout pratiquons avec fierte le French kiss
Lehpron From United States of America, joined Jul 2001, 7028 posts, RR: 20
Reply 13, posted (11 years 2 months 3 weeks 1 day 4 hours ago) and read 9142 times:
Quoting DeltaMD11 (Reply 9): Granted drag is decreased but that is only realized at higher speeds during cruise.
Don't listen to pilots dude, they only know how to fly it and not how it flys.
Induced drag is highest with flaps engaged, ususally take off and landing. Reducing that effect result in a higher L/D ratio and higher take off angle. You've seen pictures of th X-29 forward-swept wing concept from the 1980's? Its wings kill off any wingtip flow, in fact the drag is 29% less due to the wing arraingment -- thus massive L/D ratio.
The picture clearly shows a 30-degree climb angle, which translates to a half-gravity acceleration!
[Edited 2005-03-10 22:11:02]
The meaning of life is curiosity; we were put on this planet to explore opportunities.
DeltaMD11 From United States of America, joined Dec 2002, 1709 posts, RR: 30
Reply 17, posted (11 years 2 months 3 weeks 1 day 4 hours ago) and read 9057 times:
Yes but the aircraft pictured above is not climbing like that because the winglets have been added, its a simple low weight high performance takeoff which can be done just like that in any 757 winglets or not. I'm not saying that the winglets do not provide ANY performance advantages to the aircraft, but some of the comments on this thread would lead one to believe that this aircraft is pitched up like that due to the addition of the winglets which is not true.
Edit: Oh I forgot, on what Lehpron was saying: "Induced drag is highest with flaps engaged, ususally take off and landing. Reducing that effect result in a higher L/D ratio and higher take off angle."
I realize this as well but again the true decrease in drag is only during cruise at altitude and speed. The amount of drag that the winglets reduce over the regular wingtip of a 757 in comparison with the amount of drag created by flap extension during takeoff still would not account for that much of an increase in climb angle. If anything, you're looking more at lift benefits during takeoff than power which makes such a high AOA possible. Arguably if you have a very large high-lift wing compared to a small lower-lift wing you're going to need to pitch up higher on the lower lift wing to achieve the same rate of climb as you would with a larger higher-lift wing.
[Edited 2005-03-10 22:35:37]
Too often we ... enjoy the comfort of opinion without the discomfort of thought. - John Fitzgerald Kennedy
Lightsaber From United States of America, joined Jan 2005, 15664 posts, RR: 100
Reply 19, posted (11 years 2 months 3 weeks 1 day 3 hours ago) and read 8839 times:
AIRLINERS.NET CREW FORUM MODERATOR
Quoting Danny (Reply 15): Who cares? They are not going to do it with passengers anyway.
Wanna bet? Ever fly out of SNA? Seriously, with SNA being slot (noise) limited, I wonder if with the winglets if CO could replace the non-stop 737 on SNA-EWR with the 757? I'd fly that rollercoaster! (And yes, I know the 752's are planned for trans-Atlantic... I can hope!)
Note: All I know is that with the reduced induced drag on the 737 the takeoff length was reduced a few hundred feet due to a fractionally reduced takeoff speed (minor) and mostly due to improved engine out climb performance. To restate, most of the reduction in required takeoff runway length for the 737 is due to climb improvements when thrust from one of the engines is lost (recall takeoff lengths must include a little safety margin for reasonable "events."). I would assume with a wingletted 752 the same physics would apply and there would be a reduction in required runway length; probably less as proportionately the winglet size is reduced (same winglets on a larger/heavier airframe).
Has there been any data released on the required takeoff lengths? In particular, is their a change in the "ICAO +27" wet that airlines seem to buy aircraft at. (That always seemed to be the make or break condition to be analyzed...)
"They did not know it was impossible, so they did it!" - Mark Twain
Clickhappy From United States of America, joined Sep 2001, 9823 posts, RR: 64
Reply 24, posted (11 years 2 months 3 weeks 1 day 2 hours ago) and read 8489 times:
Here is some more info on this takeoff, from a member of the flightcrew:
"Yesterdays takeoff was not maximum performance - we were using max derate. Takeoff weight was 168,000 lbs, and we climbed at a V2 of 132 Knots to 1500 feet, with a deck angle of 33 degrees. It was a GREAT ride."
: Kind of reminds me of the Blue Angles 'Fat Albert' taking off with JATO rockets lit up!
: I think he means something along the lines of crazy stupid.. not stupid retarded..
: Oh yeah, I've flown out of SNA on an AA 757 and let me tell you, that is the only time I felt a plane put me on my back. I don't know what the angle w
: Amazing shot Contrast that with the 321 which struggles to become airbourne! You haven't seen many 321's then Sam
: I agree, A346. The 321s can hold their own, as long as they're not doing US transcons..
: Just to add one thing originally there was a problem that we were told with the 757's and winglets.... They flew just too well! Upon landing they woul
: Do the winglets help with high altitude or hot weather takeoffs? I was last on a 757 last August EWR-SEA, with maybe a 50% load, and it took off stron
: Awesome pic--thanks for posting. Here's to one of the finest aircraft ever built!
: You stole my thunder. I have been rocketing out of MDW on 757-200s and -300s for 2 years working for TZ. Full or empty out of MDW it feels like rocket
: Actually, I would agree with the statement that the A321 struggles a bit.
: Ok to make some of you guys jealous, I flew jumpseat on a TWA 757 that was being ferried from MCO to STL. The plane was empty except for me, two pilot
: I like winglets for their fuel savings. I like the look of winglets on the 737. But, they just don't look right on the 757.
: I can see where you're coming from especially since the 757 so revered as is, but I gotta say the winglets make it look even faster and more athletic
: dont ya just love the 757 hope to be on a BA one at the end of the month to LHR. There take offs at MAN are WOW
: I was almost disappointed in take-off performance of a CO B753. Why almost? Well, this plane is actually pretty long. I expected that it would take a
: The picture is minimized to fit within the frame, expand it to full view and there is zero pixilation.
: It looks like the CO "winglet rocket" is doing some test flights between TUS and ELP today (3/12/05). See: http://www.airlinepostcard.com/co_n67134_te