Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
767-300ER Handling Implications Of Blended Winglet  
User currently offlineJaggySnake From United Kingdom, joined Oct 2012, 6 posts, RR: 0
Posted (2 years 1 month 2 weeks 6 days ago) and read 5024 times:

Hi guys,


I've only just bought a membership to this place, yet like many of my classmates, I could probably credit my degree to the help of these forums!!

Anyway I'm on an internship (for my final year thesis) at an MRO doing a study of blended winglets, in particular, the installation of the Aviation Partners' product onto the 767-300ER.

I am interested to hear some views from current Flight Crew on any effects the installation of winglets has on the handling characteristics of the plane.
I have already spoken to a UA test pilot who was recently performing the post-mod test flight on one of their a/c and he suggested that there is little noticeable difference to the way the a/c handles following winglet installation. He did however admit that he wasn't the best person for me to ask as he does not exclusively fly the 767s.

I'm thinking that by adding these devices - they're really quite substantial on the 767-300 - there could be an increase to the dihedral effect of the wing adding some extra roll damping. As the effective aspect ratio is increased, the Mean Aerodynamic Chord is perhaps shifted towards the tips slightly? Combining that with the presumed aftwards shift of the longitudinal centre of gravity due to the winglet's weight, are there any performance implications upon take-off/landing which are at all noticeable?

I ask here as I have so far been unable to find any evidence to back-up these ideas.

I'm expecting you guys to come back and say that any differences are negligible, and I'm perhaps being optimistic in that I'm looking for anything that will add depth to my report, but any help on this issue would be greatly appreciated.


Cheers, Fergus

11 replies: All unread, jump to last
 
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 1, posted (2 years 1 month 2 weeks 5 days 8 hours ago) and read 4813 times:

Quoting JaggySnake (Thread starter):
I'm expecting you guys to come back and say that any differences are negligible, and I'm perhaps being optimistic in that I'm looking for anything that will add depth to my report, but any help on this issue would be greatly appreciated.

One way to look at it is that, if the difference *weren't* negligable, the FAA et. al. would require either additional training or a new type rating. So far as I know, that hasn't happened.

Tom.


User currently offlineDocLightning From United States of America, joined Nov 2005, 20246 posts, RR: 59
Reply 2, posted (2 years 1 month 2 weeks 5 days 7 hours ago) and read 4790 times:

Quoting tdscanuck (Reply 1):
One way to look at it is that, if the difference *weren't* negligable, the FAA et. al. would require either additional training or a new type rating. So far as I know, that hasn't happened.

I thought that the winglets knocked a few Kt off the maximum allowable crosswind in a landing/takeoff.


User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 3, posted (2 years 1 month 2 weeks 5 days 2 hours ago) and read 4726 times:

Quoting DocLightning (Reply 2):
I thought that the winglets knocked a few Kt off the maximum allowable crosswind in a landing/takeoff.

If so, that's almost guaranteed to be due to available test data rather than an actual aerodynamic limitation...maximum allowable crosswind is just maximum demonstrated...the OEM's knock themselves out trying to find this highest crosswind you can while you've got an FAA-authorized test pilot onboard but you don't always get what you want. At some point, you give up being on wind watch because you've got a number that's good enough.

Tom.


User currently offlineMax Q From United States of America, joined May 2001, 4751 posts, RR: 18
Reply 4, posted (2 years 1 month 2 weeks 4 days 19 hours ago) and read 4631 times:

Never noticed any difference on the 757 or 767.


Except a little more tendency to float on landing if you are fast.



The best contribution to safety is a competent Pilot.
User currently offlineN243NW From United States of America, joined Jul 2003, 1639 posts, RR: 20
Reply 5, posted (2 years 1 month 2 weeks 4 days 1 hour ago) and read 4499 times:

Quoting DocLightning (Reply 2):
I thought that the winglets knocked a few Kt off the maximum allowable crosswind in a landing/takeoff.

My airline actually queried Aviation Partners Boeing about this (why the 30kt value for the 757 and 29kt value for the 767 remain unchanged), and the response was that APB was able to better the non-winglet Boeing figures with the wingleted aircraft during flight test (remember, they're demonstrated values, not limits!). For this reason, APB considered the effects of winglets negligible on crosswind behavior.



B-52s don't take off. They scare the ground away.
User currently offlineJaggySnake From United Kingdom, joined Oct 2012, 6 posts, RR: 0
Reply 6, posted (2 years 1 month 2 weeks 4 days ago) and read 4455 times:

OK, thanks for the replies.

Quoting Max Q (Reply 4):

Except a little more tendency to float on landing if you are fast.

I would have thought, if anything, the ground effect would be reduced due to a lesser amount of induced velocity from reduced trailing vortices?


User currently offlineMax Q From United States of America, joined May 2001, 4751 posts, RR: 18
Reply 7, posted (2 years 1 month 2 weeks 3 days 21 hours ago) and read 4410 times:

Quoting JaggySnake (Reply 6):


Quoting Max Q (Reply 4):

Except a little more tendency to float on landing if you are fast.

I would have thought, if anything, the ground effect would be reduced due to a lesser amount of induced velocity from reduced trailing vortices?

It's the overall drag being lower that makes the difference, you raise an interesting point though.



The best contribution to safety is a competent Pilot.
User currently offlineTWA772LR From United States of America, joined Nov 2011, 2347 posts, RR: 1
Reply 8, posted (2 years 1 month 1 week 6 days 8 hours ago) and read 3953 times:

What effect would winglets have on a crosswind landing/takeoff? Would they disrupt the aircraft in anyway? Didn't that used to be one of the theories of the CO DEN crash?


Go coogs! \n//
User currently offlineDocLightning From United States of America, joined Nov 2005, 20246 posts, RR: 59
Reply 9, posted (2 years 1 month 1 week 5 days 2 hours ago) and read 3668 times:

Quoting N243NW (Reply 5):
My airline actually queried Aviation Partners Boeing about this (why the 30kt value for the 757 and 29kt value for the 767 remain unchanged), and the response was that APB was able to better the non-winglet Boeing figures with the wingleted aircraft during flight test (remember, they're demonstrated values, not limits!). For this reason, APB considered the effects of winglets negligible on crosswind behavior.

Couldn't Boeing use these results to alter the maximum allowable crosswind for the 767 type?


User currently offlineN243NW From United States of America, joined Jul 2003, 1639 posts, RR: 20
Reply 10, posted (2 years 1 month 1 week 4 days 22 hours ago) and read 3605 times:

Quoting DocLightning (Reply 9):
Couldn't Boeing use these results to alter the maximum allowable crosswind for the 767 type?

There would likely be no real benefit, considering that these conditions are so rarely encountered. Also, Boeing probably wouldn't increase the aircraft's book values without doing the necessary testing themselves, for liability reasons.



B-52s don't take off. They scare the ground away.
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 11, posted (2 years 1 month 1 week 4 days 13 hours ago) and read 3532 times:

Quoting DocLightning (Reply 9):
Couldn't Boeing use these results to alter the maximum allowable crosswind for the 767 type?

There is no maximum allowable crosswind, only max demonstrated. To count as "demonstrated" the OEM has to have done it with an FAA or AR pilot onboard and instrumentation to provide the data backup, and analysis to show that the with-winglet value is applicable to the without-winglet airplane. It's entirely possible that whatever APB did did not meet that threshold.

Tom.


Top Of Page
Forum Index

Reply To This Topic 767-300ER Handling Implications Of Blended Winglet
Username:
No username? Sign up now!
Password: 


Forgot Password? Be reminded.
Remember me on this computer (uses cookies)
  • Tech/Ops related posts only!
  • Not Tech/Ops related? Use the other forums
  • No adverts of any kind. This includes web pages.
  • No hostile language or criticizing of others.
  • Do not post copyright protected material.
  • Use relevant and describing topics.
  • Check if your post already been discussed.
  • Check your spelling!
  • DETAILED RULES
Add Images Add SmiliesPosting Help

Please check your spelling (press "Check Spelling" above)


Similar topics:More similar topics...
Empty Weight Range Of 767-300ER? posted Fri Mar 23 2007 18:56:05 by Jamesbuk
767-300ER Winglet posted Mon Feb 12 2007 03:53:07 by DeltaL1011man
BA 767-300ER RR posted Wed Dec 14 2011 07:57:26 by JQflightie
767-300ER Wing Vortex Generators? posted Tue Jan 4 2011 01:23:59 by DocLightning
Delta 767-300ER Fuselage - Small Square Part posted Fri Oct 15 2010 01:15:17 by Bruce
The Latest On The Blended Winglet 763ER? posted Fri Jan 9 2009 15:46:53 by UAL747
Implications Of Total Avionics Loss T7--- posted Thu Jan 17 2008 10:43:30 by ImperialEagle
767-300 To 767-300ER posted Wed Sep 26 2007 22:36:58 by FlyASAGuy2005
767-300ER With Winglets posted Fri Apr 20 2007 21:10:19 by SunriseValley
Blended Winglet Question posted Fri Mar 23 2007 14:31:15 by Kmh1956

Sponsor Message:
Printer friendly format