Moolies
Topic Author
Posts: 476
Joined: Fri Nov 07, 2003 2:59 am

Why No Wingtips On The 777?

Fri Dec 26, 2003 2:13 am

Hi, I was wondering why there are no wing tips on the 777?

What is the reason?
 
rthrbeflying86
Posts: 241
Joined: Sun Oct 12, 2003 12:31 am

RE: Why No Winglets On The 777?

Fri Dec 26, 2003 2:14 am

I'm pretty sure you mean winglets....not having wing tips might prove to be quite a problem.

Merry Christmas!
I'd rather be flying.
 
Big777jet
Posts: 2682
Joined: Mon May 01, 2000 10:52 am

RE: Why No Wingtips On The 777?

Fri Dec 26, 2003 2:28 am

Actually, the only Boeing 777-300ER has raked winglets same as Boeing 767-400.

Merry XMas!

Big777jet



[Edited 2003-12-25 18:41:57]
 
rjpieces
Posts: 6849
Joined: Mon Nov 24, 2003 8:58 am

RE: Why No Wingtips On The 777?

Fri Dec 26, 2003 2:39 am

The 777s wing was designed powerful and excellent enough not to need winglets.
"Millions long for immortality who do not know what to do with themselves on a rainy Sunday afternoon"
 
KLM777
Posts: 361
Joined: Thu Dec 25, 2003 1:00 am

RE: Why No Wingtips On The 777?

Fri Dec 26, 2003 2:43 am

The wing of the 777 is very long and at the end very thin. This means there is less induced drag than on a standard wing, because there is less air moving from below the wing to the top of the wing.

Maybe winglets could even increase the efficiency, but winglets means weight and especially at the end of the wing this is not a very positive thing (the weight itself has to be carrier up which costs fuel but it also creates more momentum and thus bigger joints and structure at the root of the wing). So if you weigh up the pros and cons winglets do not always increase efficiency.

I hope I explained this well.

Kind regards,

Jeroen
Every landing is a controlled crash
 
zak
Posts: 1926
Joined: Mon Sep 22, 2003 12:17 pm

RE: Why No Wingtips On The 777?

Fri Dec 26, 2003 2:47 am

i dont know how a wing is designed powerful, but besides that, the 777 wing was designed in a way that the wingtip vortex is minimal, therefore the weight of any special structure on the wingtip (rake or winglet or whatever) would outweight the gain from it.
that calculation seems to have changed in favour of the raked tip with the 300ER and 200LR, therefore they have raked tips.
it is all a matter of efficiency, similar with the 737NG. to some operators the savings make sense, to others the efficiency gain does not outweight the penalty from the weight, therefore they are not economical.
the wingtip game is just like any other game in aviation, you only add weight if you get enough improvement out of it to make up for it.
in some cases this is just not the case.
10=2
 
gigneil
Posts: 14133
Joined: Fri Nov 08, 2002 10:25 am

RE: Why No Wingtips On The 777?

Fri Dec 26, 2003 3:34 am

This topic has been beaten to death in tech/ops, and I'm pretty sure Moolies was a participant in one of those threads.  Laugh out loud

The wing was extremely efficient without any winglet or fence.

The 777-200LR and 777-300ER both have raked wingtips.

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