jcded
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747 LCF No Winglets?

Thu Dec 07, 2006 12:32 pm

I was looking at boeingmedia.com and the picture of the "Dreamlifter" shows the plane without winglets, originally it was drawn with winglets, now it doesnt and the picture shows it without.

Any idea why they removed them, I mean with the extra weight, wouldn't they need the improved efficiency from the winglets?


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Cleared2Land4
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RE: 747 LCF No Winglets?

Thu Dec 07, 2006 1:13 pm

hmmm i see them on the aircraft.....
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osiris30
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RE: 747 LCF No Winglets?

Thu Dec 07, 2006 1:16 pm

Uhhh.. what do you think the things on the end of the wing are :P

Look at the white 'triangle' by the tail in the photo  Wink
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
ZBBYLW
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RE: 747 LCF No Winglets?

Thu Dec 07, 2006 1:21 pm

Right under the eponage there is this white "thing" that sticks out. This is the winglet you are looking for  Wink
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ha763
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RE: 747 LCF No Winglets?

Thu Dec 07, 2006 1:29 pm

That's the wrong picture. Here's the latest one showing no winglets:


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Photo © Erick Lopez


BTW, there already was post about this a couple of days ago:
http://www1.airliners.net/discussion...eneral_aviation/read.main/3129737/

[Edited 2006-12-07 05:33:37]
 
Stealthz
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RE: 747 LCF No Winglets?

Thu Dec 07, 2006 1:32 pm

I think our Swiss friend is actually referring to the picture at boeingmedia.com, it shows the announced "DreamLifter" livery without winglets
http://boeingmedia.com/imageDetail.cfm?id=14678&clr=release

jcded, I am pretty certain that picture is an artists impression, I would be surprised if they removed the winglets.

Cheers
If your camera sends text messages, that could explain why your photos are rubbish!
 
alexchao
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RE: 747 LCF No Winglets?

Thu Dec 07, 2006 1:37 pm

I'm pretty sure the winglets have been removed, and the artists rendition is accurate. Does anyone know why?
 
osiris30
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RE: 747 LCF No Winglets?

Thu Dec 07, 2006 1:38 pm

Quoting Ha763 (Reply 4):
That's the wrong picture. Here's the latest one showing no winglets:

Might have been removed for testing purposes?
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
Curmudgeon
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RE: 747 LCF No Winglets?

Thu Dec 07, 2006 1:40 pm

Were these things all -400's before modification?

Also, I wonder how much advantage the winglets would provide at the (I imagine) lower cruise speeds of the LCF?

I do note that the in-house nickname for the LCF was "drag queen"; the incremental benefits of the winglets may have been insignificant in the long run.
Jets are for kids
 
JRadier
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RE: 747 LCF No Winglets?

Thu Dec 07, 2006 9:00 pm

Quoting Osiris30 (Reply 7):
Might have been removed for testing purposes?

could be. The winglets on the 744 are MEL items and increase fuel burn if removed. Might be testing that?
For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and ther
 
SEAdomer787
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RE: 747 LCF No Winglets?

Thu Dec 07, 2006 11:58 pm

Man, this forum never ceases to amaze me. Yesterday when a friend and I were leaving the 787 virtual rollout, where they revealed the LCF new livery, we had two speculations:

1) Someone would post a blurb about the new livery in a matter of minutes. Done.
2) Someone would start a thread about there not being winglets all of a sudden. Done.

Too Funny!!
 
beech19
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RE: 747 LCF No Winglets?

Fri Dec 08, 2006 4:03 am

Quoting Curmudgeon (Reply 8):
Also, I wonder how much advantage the winglets would provide at the (I imagine) lower cruise speeds of the LCF?

Yes... much lower. When they were coming from Taiwan to BFI they averaged around 430knots. WAY lower than a normal 747 going eastbound.
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777MechSys
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RE: 747 LCF No Winglets?

Fri Dec 08, 2006 11:08 am

Greetings from Taipei.

Quoting Curmudgeon (Reply 8):
re these things all -400's before modification?

Yes. So far all 747's obtained for conversion are -400s.

The last I heard there will not be winglets on the LCF. Is that a final answer? Probably not. Time will tell.

-Erick
 
thepilot
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RE: 747 LCF No Winglets?

Fri Dec 08, 2006 12:25 pm

Just recently, they were doing a test at BFI w/out winglets and they were 50,000 lbs over landing weight. I guess it is still in the experimental stage. The LCF (or the pickle's) wake turbulence that it flipped my friend's plane (C172) over Elliot Bay. That plane's wake is a monster!
From YVR
 
beech19
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RE: 747 LCF No Winglets?

Fri Dec 08, 2006 1:55 pm

Quoting Thepilot (Reply 13):
Just recently, they were doing a test at BFI w/out winglets and they were 50,000 lbs over landing weight. I guess it is still in the experimental stage.

Where did you hear it was 50,000lbs over weight? I'm a bit skeptical of that. If it was 50,000lbs over landing weight that aircraft would have weighed in between 625,000 and 680,000lbs when it hit the runway. I'd be rather surprised if that were true being as close to certification as they are, why risk the airframe? Why fly it 50K over in the first place? It won't be close to over weight while carrying a 787 load.

Its experimental stage will be ending in about 2 weeks when it gets its cert.
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777MechSys
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RE: 747 LCF No Winglets?

Fri Dec 08, 2006 3:06 pm

Quoting Thepilot (Reply 13):
That plane's wake is a monster!

Name 1 heavy lifter that isn't a wake monster. That is why ATC says "Caution wake turbulence."

Actually it wasn't "overweight". It was heavier than the landing weight it will be certified for. Nothing unusual here for a aircraft being test and certified.

[Edited 2006-12-08 07:08:42]
 
thepilot
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RE: 747 LCF No Winglets?

Sat Dec 09, 2006 11:03 am

Quoting 777MechSys (Reply 15):
Name 1 heavy lifter that isn't a wake monster. That is why ATC says "Caution wake turbulence."

No doubt about that, but without winglets and 50k overweight, its wake turbulence is much greater than when it has winglets and it at normal landing weight.

I fly out of BFI (& go up to PAE a bunch) and thus am around lots of heavies (and the B757), and know lots of pilots who fly around the area. Everyone at my FBO seems to agree that the LCF without winglets should be avoided at all costs, even going around at TPA if necessary.
From YVR
 
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RobK
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RE: 747 LCF No Winglets?

Sat Dec 09, 2006 11:18 am

Quoting Thepilot (Reply 16):
Everyone at my FBO seems to agree that the LCF without winglets should be avoided at all costs...

... but it'll be okay to fly near it in a 152 if it does have winglets, right?

 rotfl 

R
 
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kc135topboom
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RE: 747 LCF No Winglets?

Sat Dec 09, 2006 10:38 pm

Perhaps it is a flight test? While winglets do improve fuel comsumption, they also reduce the crosswind componet.
 
777MechSys
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RE: 747 LCF No Winglets?

Sun Dec 10, 2006 2:50 am

LCF will not have winglets.

Quick update. The tail has been opened on the second one.
 
legoguy
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RE: 747 LCF No Winglets?

Sun Dec 10, 2006 3:00 am

Maybe the different sized fuselage of the LCF compared to the original 747 means that the winglets are not suited to the slightly different sized wings (do the wings of the LCF have the same surface area as the original 744?)
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777MechSys
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RE: 747 LCF No Winglets?

Sun Dec 10, 2006 4:15 am

Quoting Legoguy (Reply 20):
do the wings of the LCF have the same surface area as the original 744?)

The wings on the LCF sre the same as the 744. The verticle stab. is larger but the wings did not change.
 
legoguy
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RE: 747 LCF No Winglets?

Sun Dec 10, 2006 5:01 am

Quoting 777MechSys (Reply 21):
The wings on the LCF sre the same as the 744.

Im just looking at the picture of the LCF now and just realizing that the fuselage where the wings meet the fuselage is exactly the same as the 747. The fuselage isn't widened until above the bulge at the bottom (whats the name of that bulge!?!?!)
Can you say 'Beer Can' without sounding like a Jamaican saying 'Bacon'?
 
777MechSys
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RE: 747 LCF No Winglets?

Sun Dec 10, 2006 5:28 am

Quoting Legoguy (Reply 22):
the bulge at the bottom (whats the name of that bulge!?!?!)

Are you talking about the fairings? Painted white (on current LCF) and blends the wing into the body.
 
legoguy
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RE: 747 LCF No Winglets?

Sun Dec 10, 2006 8:37 am

Quoting 777MechSys (Reply 23):
Are you talking about the fairings? Painted white (on current LCF) and blends the wing into the body.

Yup thats them. I was thinking the fuselage was widened around the fairings aswell thus reducing the wing area, but not the case.
Can you say 'Beer Can' without sounding like a Jamaican saying 'Bacon'?
 
sjot
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RE: 747 LCF No Winglets?

Sun Dec 10, 2006 8:47 am

Winglets clipped from converted 747
The Seattle Times

The converted 747 air freighter with a bulging upper fuselage parked at Boeing Field has had its winglets clipped.

Starting in January, Boeing plans to use the big transporter — renamed this week the Dreamlifter — to carry sections of the 787 Dreamliner around the globe. It arrived in Seattle from Taiwan in September sporting standard 747 winglets, the upward swooping wingtips that reduce fuel burn and increase the range of a regular 747 by about 3 percent.

Spokeswoman Mary Hanson said Boeing removed the winglets after flight tests showed that in the tradeoff between aerodynamic performance, handling in flight and structural design capability, they were unnecessary.

The Dreamlifter wings will instead terminate with a standard 747-400 straight cutoff.

The airplane is undergoing flight tests so it can be certified to next month begin ferrying the first 787 sections.
 
JRadier
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RE: 747 LCF No Winglets?

Sun Dec 10, 2006 9:11 pm

Quoting Sjot (Reply 25):
standard 747-400 straight cutoff.

right..... A standard 744 wing has winglets...
For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and ther
 
rootsair
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RE: 747 LCF No Winglets?

Sun Dec 10, 2006 9:35 pm

Dream lifter is sooo ugly. Long live the Beluga !
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beech19
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RE: 747 LCF No Winglets?

Mon Dec 11, 2006 3:14 am

Quoting JRadier (Reply 26):
right..... A standard 744 wing has winglets...

Oh good point... but a 744D doesn't.  Wink

Quoting RootsAir (Reply 27):
Dream lifter is sooo ugly. Long live the Beluga !

Yeah... the beluga is one sexy plane. (you can note my sarcasm...)
KPAE via KBVY
 
JRadier
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RE: 747 LCF No Winglets?

Mon Dec 11, 2006 3:57 am

Quoting Sjot (Reply 25):
The Dreamlifter wings will instead terminate with a standard 747-400 straight cutoff.



Quoting Beech19 (Reply 28):
Oh good point... but a 744D doesn't. Wink

that's not what they said did they  Wink
For once you have tasted flight you will walk the earth with your eyes turned skywards, for there you have been and ther
 
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kc135topboom
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RE: 747 LCF No Winglets?

Mon Dec 11, 2006 5:34 am

Quoting RootsAir (Reply 27):
Dream lifter is sooo ugly. Long live the Beluga !

You must need glasses, my friend.  vomit 
 
Devilfish
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RE: 747 LCF No Winglets?

Tue Dec 12, 2006 4:22 am

Quoting Sjot (Reply 25):
Spokeswoman Mary Hanson said Boeing removed the winglets after flight tests showed that in the tradeoff between aerodynamic performance, handling in flight and structural design capability, they were unnecessary.

Here we may have the plain translation of the above "corporatese" .....

http://www.flightglobal.com/Articles...CF+tests+slip+behind+schedule.html

Quote:
Vibration issues have required 747 LCF test flights with winglets removed

"Although details remain scarce, Boeing says the test team is tackling vibration issues that have led to the removal of the winglets from the first Dreamlifter test aircraft (RT876). Flutter tests, provisionally expected to have been completed by now, were still under way as of 7 December."
"Everyone is entitled to my opinion." - Garfield
 
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N328KF
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RE: 747 LCF No Winglets?

Tue Dec 12, 2006 4:26 am

Quoting RootsAir (Reply 27):
Dream lifter is sooo ugly. Long live the Beluga !

None of the outsize aircraft (A300-600ST, 747-400 LCF, and the Guppys) are particularly attractive, IMHO. The C-5 and An-124/An-225 are far more elegant looking.
When they call the roll in the Senate, the Senators do not know whether to answer 'Present' or 'Not guilty.' -Theodore Roosevelt
 
aeroguy
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RE: 747 LCF No Winglets?

Tue Dec 12, 2006 5:03 am

Quoting DEVILFISH (Reply 31):
Vibration issues have required 747 LCF test flights with winglets removed

"Although details remain scarce, Boeing says the test team is tackling vibration issues that have led to the removal of the winglets from the first Dreamlifter test aircraft (RT876). Flutter tests, provisionally expected to have been completed by now, were still under way as of 7 December."

Good find there DEVILFISH. Right on the money too. You guys can stop worrying about the LCF aerodynamic performance, the winglet decision is being driven by flutter.
 
aeroman444
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RE: 747 LCF No Winglets?

Tue Dec 12, 2006 5:21 am

Oh, there is a reason why they are not there.  Big grin
 
LeanOfPeak
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RE: 747 LCF No Winglets?

Wed Dec 13, 2006 11:35 am

Winglets result in a decrease in induced drag (Drag due to a finite wing producing lift) and an increase in parasite (Form) drag. The idea is that usually the former outweighs the latter.

A consequence of decreasing induced drag (Which decreases with airspeed) and increasing parasite drag (Which increases with airspeed) as that the optimum cruise and L/D airspeeds are reduced. The general guideline that is commonly used is that at max L/D, the parasite and induced components of drag are usually approximately equal.

Given 1) A lower cruise altitude and 2) A less-svelte form, both of which increase parasite drag, it seems apparent that minimizing parasite drag and accepting some amount of penalty in induced drag in order to retain some kind of cruise speed might be desirable.