Sponsor Message:
Aviation Technical / Operations Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
Why Don't Some Spoiler Panels Line Up?  
User currently offlineTrichos From United States of America, joined Sep 2003, 22 posts, RR: 0
Posted (6 years 10 months 1 day 9 hours ago) and read 3009 times:

Just a question of curiosity.
I've noticed that on landing the spoiler panels on some aircraft don't seem to go up the same amount (737's?). In other aircraft they all seem to go up the same amount and line up. Is this a common to some aircraft models? Is it just sign or wear or loss of calibration? Is it a design feature, as there may be less room for the mechanism in some wing areas?

Example. http://www.airliners.net/open.file?i...19&prev_id=1167724&next_id=1166095
In some videos from the window view it seems to be a more random line up.

Thanks

13 replies: All unread, jump to last
 
User currently offlineTristarsteve From Sweden, joined Nov 2005, 3930 posts, RR: 34
Reply 1, posted (6 years 10 months 1 day 7 hours ago) and read 2981 times:

It is a design feature, and its pretty common on most airliners.

User currently offline474218 From United States of America, joined Oct 2005, 6340 posts, RR: 9
Reply 2, posted (6 years 10 months 1 day 1 hour ago) and read 2875 times:

There are limits to the amount the spoiler panels should deploy (both minimum and maximum). As long as they are within the limits no re-rigging is required, so some may not appear to be deployed as far as others it is normal.

User currently offlineRoseFlyer From United States of America, joined Feb 2004, 9378 posts, RR: 52
Reply 3, posted (6 years 10 months 18 hours ago) and read 2825 times:

One thing to note is that there are two types of spoilers. There are inflight spoilers and ground spoilers.

The spoilers are interesting because they take the most hydraulic fluid of anything on the plane normally to run since they experience high forces when in flight.

As far as the placement goes, they are located closely in regards to where the flaps deploy. I'm not an aero guy, so I can't say why they deploy to different angles, but I guess that it has something to do with a large flat plate would have some weird vorticies coming off of it that probably should be avoided.



If you have never designed an airplane part before, let the real designers do the work!
User currently offline411A From United States of America, joined Nov 2001, 1826 posts, RR: 8
Reply 4, posted (6 years 10 months 11 hours ago) and read 2738 times:

Quoting RoseFlyer (Reply 3):
The spoilers are interesting because they take the most hydraulic fluid of anything on the plane normally to run since they experience high forces when in flight.

Nonsense.

Spoilers use very little hydraulic fluid displacement for their operation...landing gear and flaps/slats use far more.

Quoting RoseFlyer (Reply 3):
I'm not an aero guy....

I would imagine so, and it shows.


User currently offlineRoseFlyer From United States of America, joined Feb 2004, 9378 posts, RR: 52
Reply 5, posted (6 years 10 months 9 hours ago) and read 2712 times:

Quoting 411A (Reply 4):
Quoting RoseFlyer (Reply 3):
The spoilers are interesting because they take the most hydraulic fluid of anything on the plane normally to run since they experience high forces when in flight.

Nonsense.

Spoilers use very little hydraulic fluid displacement for their operation...landing gear and flaps/slats use far more.

You are right that it makes no sense now. I might be typically off kilter here, but from what I understand, they are a high demand system and from my experience they use the most fluid of any system on the ground. They take more fluid to operate than the thrust reversers, elevators, rudders or ailerons. Unlike the landing gear per se, the spoilers require a constant fluid pressure to be maintained in the up position. Landing gear takes a lot of force and fluid to retract, but that's not a continuous operation. Each spoiler actuator (2 per spoiler) is smaller than the landing gear actuator, but collectively with full spoilers up, the actuators are a high demand system.

[Edited 2007-06-23 18:35:47]


If you have never designed an airplane part before, let the real designers do the work!
User currently offlineTristarSteve From Sweden, joined Nov 2005, 3930 posts, RR: 34
Reply 6, posted (6 years 10 months 8 hours ago) and read 2690 times:

Quoting RoseFlyer (Reply 5):
You are right that it makes no sense now. I might be typically off kilter here, but from what I understand, they are a high demand system and from my experience they use the most fluid of any system on the ground. They take more fluid to operate than the thrust reversers, elevators, rudders or ailerons. Unlike the landing gear per se, the spoilers require a constant fluid pressure to be maintained in the up position. Landing gear takes a lot of force and fluid to retract, but that's not a continuous operation. Each spoiler actuator (2 per spoiler) is smaller than the landing gear actuator, but collectively with full spoilers up, the actuators are a high demand system.

Lets take the B737 as your picture shows it.
The B737-200 has 8 spoilers, the B747-400 has 10.
They work in exactly the same way. They are numbered (on-400) 0 to 9 left wing tip to right wing tip.
Spoilers 0 1 4 5 8 9 are ground spoilers Spoilers 2 3 6 7 are ground and flight spoilers.
The ground spoilers extend to 60 deg, the flight spoilers to 40 deg.
The ground spoilers are up or down. There is no intermediate posn, and the actuators, one per spoiler except 4 and 5 which have 2 each, lock in the fully extended, and fully retracted posn.
The flight spoilers are fully variable and are used as speedbrakes and roll assist as well as ground spoilers. If there is an input from the control wheel, the flight spoilers may retract during landing as the ailerons move.
The B737NG has a nearly identical system. I.e. it is fully mechanically controlled and still has that wonderfull piece of engineering in the wheel well, the spoiler mixer.
There is no special hydraulic supply for the ground spoilers, unlike the B777 which runs up the ADP to supply more hyd flow on landing.
The spoiler lever in the flight deck can always be selected, but on landing it is usually driven to the deploy position by an electric motor automatically, basically on wheel spin up. If the right main gear oleo is depressed enough a teleflex cable operates the ground spoiler selector and they will go up as well.
On new aircraft from B757 onwards spoilers are all electronically controlled, and the displacement is not so even.
For some reason Boeing stayed with mechanical control on the NG, must have been cheaper than changing to computor control.


User currently offlineRedFlyer From United States of America, joined Feb 2005, 4252 posts, RR: 29
Reply 7, posted (6 years 10 months 8 hours ago) and read 2686 times:

Quoting TristarSteve (Reply 6):
They work in exactly the same way. They are numbered (on-400) 0 to 9 left wing tip to right wing tip.

Just curious, but why would a spoiler (or any other device) be numbered "0"? I've only seen "0" applied as a device number on computer equipment (e.g., hard disk 0, 1, etc.). They don't number the engines 0, 1, 2, 3, so why number another piece of mechanical device as such?



I'm not a racist...I hate Biden, too.
User currently offlineHAWK21M From India, joined Jan 2001, 31573 posts, RR: 57
Reply 8, posted (6 years 10 months 8 hours ago) and read 2685 times:

The Inbd normally Rise less in Air & more on Grd.A pair one on each side are only Grd Speed brakes on the B752.On the B732 The Inbd Spoilers are only Grd Speed brakes & deflect the most.

regds
MEL



Think of the brighter side!
User currently offlineTristarSteve From Sweden, joined Nov 2005, 3930 posts, RR: 34
Reply 9, posted (6 years 10 months 8 hours ago) and read 2682 times:

Quoting RedFlyer (Reply 7):
Just curious, but why would a spoiler (or any other device) be numbered "0"? I've only seen "0" applied as a device number on computer equipment (e.g., hard disk 0, 1, etc.). They don't number the engines 0, 1, 2, 3, so why number another piece of mechanical device as such?

because the -200 had 8 spoilers, 1 to 8, and the -400 added one at each end.


User currently offlineRedFlyer From United States of America, joined Feb 2005, 4252 posts, RR: 29
Reply 10, posted (6 years 10 months 6 hours ago) and read 2660 times:

Quoting TristarSteve (Reply 9):
because the -200 had 8 spoilers, 1 to 8, and the -400 added one at each end.

Ah, I knew you'd come up with a good explanation. Thanks!  Smile



I'm not a racist...I hate Biden, too.
User currently offlineJetMech From Australia, joined Mar 2006, 2635 posts, RR: 53
Reply 11, posted (6 years 9 months 4 weeks 1 day 22 hours ago) and read 2594 times:

Quoting RoseFlyer (Reply 3):
The spoilers are interesting because they take the most hydraulic fluid of anything on the plane normally to run since they experience high forces when in flight.

Don't forget that the spoiler system of the B744 is powered by three of the four hydraulic systems. If you situate yourself behind a 744, the spoilers, IIRC are powered by systems 3,2,2,3,4,4,4,4,3,2,2,3 when scanning across from the left hand wing to the right hand wing. Collectively, the amount of hydraulic fluid demand may be appreciable, but the load on any one hydraulic system is very reasonable.

Quoting TristarSteve (Reply 6):
B747-400 has 10.

Does the 744 have 12 spoiler panels in total  Confused .


View Large View Medium
Click here for bigger photo!

Photo © Kenneth C. Iwelumo



Regards, JetMech



JetMech split the back of his pants. He can feel the wind in his hair.
User currently offlineTristarSteve From Sweden, joined Nov 2005, 3930 posts, RR: 34
Reply 12, posted (6 years 9 months 4 weeks 1 day 9 hours ago) and read 2513 times:

Quoting JetMech (Reply 11):
Quoting TristarSteve (Reply 6):
B747-400 has 10.

Does the 744 have 12 spoiler panels in total .

Sorry mistype, I was talking about B737-400.


User currently offlineTroubleshooter From Germany, joined Feb 2005, 423 posts, RR: 5
Reply 13, posted (6 years 9 months 3 weeks 6 days 5 hours ago) and read 2345 times:

On the B737NG the flight spoiler (2,3,4,5,8,9,10,11) have different extensions to put equal loads on the wings during extension. Spoiler 2,3,10,11 deploy to max. 33° and spoiler 4,5,8,9 deploy to max. 38°. Flight spoiler reach their maximum extension when the control wheel is turned 70° or when the speed brake lever is in "UP" position.

Ground spoiler (1,6,7,12) are an independent system and deploy to max. 52° (6,7) and 60° (1,12).



This job sucks!!! I love this job!!!
Top Of Page
Forum Index

Reply To This Topic Why Don't Some Spoiler Panels Line Up?
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...
Why Are Some Carriers' Planes So Clean? posted Sun Jan 29 2006 06:59:35 by 777Daedalus
Why Don't Piston Engines Shift A La Automobile? posted Mon Jan 9 2006 23:29:23 by UAL747
Why Don't We See "Secondary Inlet Doors" Anymore? posted Sun May 9 2004 14:52:12 by YS11
Why Do Older RB 211 Start Up So Loud posted Sun Aug 24 2003 05:01:02 by 747400sp
Why Don't Jet Engines Weld Themselves To Death? posted Thu Nov 28 2002 11:36:27 by Lehpron
Why Do MD-8x Elevators Deflect Up? posted Mon Jul 22 2002 10:29:26 by Shaun3000
Why Are Some BR715 Engine Fans Black? posted Thu Jul 18 2002 04:59:45 by BR715-A1-30
Why Do Some A330´s Have A Shorter Tailcone posted Fri Aug 17 2001 09:46:19 by Ganymed
Why Don't FMC Compute V Speeds posted Sun Sep 17 2000 10:38:37 by B737
Why Some Airlines Don't Fly To Certain Airports posted Sat Nov 29 2003 09:33:05 by Paulinbna

Sponsor Message:
Printer friendly format