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EK413
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Rear Bogies Steering!

Tue Jun 06, 2006 2:31 pm

Hey A.Netter's! Big grin

I came across this pretty cool snap shot of United Airlines B747-422 N175UA taxiing out for departure....If you have a really close look at the rear bogie's they seem to be turning in another direction as opposed to what the aircraft is heading! I'm aware of the US bound flights departing to maximum weight but wasn't aware that it was to this extent!


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Enjoy!!! Big grin



EK413
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Stealthz
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RE: Rear Bogies Steering!

Tue Jun 06, 2006 2:48 pm

EK413,

The weight has nothing to do with it, that aircraft is turning on to Sydney's RWY25 and is operating flight UA839 SYD-MEL which is almost as short and light as a 747 flight gets. The turn from Twy Golf on to the runway is quite tight though.

See...
Steering Of MLG Bogies (by JumboJim747 Jun 6 2006 in Tech Ops)

cheers
If your camera sends text messages, that could explain why your photos are rubbish!
 
UA772IAD
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RE: Rear Bogies Steering!

Tue Jun 06, 2006 2:51 pm

The answer is quite simple really, and has nothing to do with weight. The MLG bogies turn in the opposite direction to swing the back end of the plane out, just a little more, so the pilot doesn't have to make as wide of a turn, especially in during tight maneuvers. It's kind of like the counter steering you see the trailer driver of a large rig fire truck.
 
Boeing Nut
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RE: Rear Bogies Steering!

Tue Jun 06, 2006 10:51 pm

Quoting UA772IAD (Reply 2):
The answer is quite simple really, and has nothing to do with weight. The MLG bogies turn in the opposite direction to swing the back end of the plane out, just a little more, so the pilot doesn't have to make as wide of a turn, especially in during tight maneuvers. It's kind of like the counter steering you see the trailer driver of a large rig fire truck.

Almost right. The whole design reasoning for the steerable main bogies is to save tearing up the tires and pavement during a phenomenon known as "tire scrub". Saves stress on the gear itself as well.

Regards
I'm not a real aeronautical engineer, I just play one on Airliners.net.
 
777DadandJr
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RE: Rear Bogies Steering!

Tue Jun 06, 2006 11:26 pm

Quoting UA772IAD (Reply 2):
The answer is quite simple really, and has nothing to do with weight.

 checkmark 

Quoting Boeing Nut (Reply 3):
Almost right. The whole design reasoning for the steerable main bogies is to save tearing up the tires and pavement during a phenomenon known as "tire scrub". Saves stress on the gear itself as well.

 checkmark 

To add,
It is my understanding that the MLG steering doesn't come into play unless the nose gear is turn more than 20 degrees. I beleive that is what is in one of the books I have at home.

Russ
My glass is neither 1/2 empty nor 1/2 full, rather, the glass itself is twice as big as it should be.
 
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EK413
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RE: Rear Bogies Steering!

Tue Jun 06, 2006 11:45 pm

Cheers guys! Big grin
I did question where this flight was bound & now that it has been brought to my attention this definately is a runway 25 departure...
Cheers once again! Big grin

EK413
Good evening, ladies and gentlemen. We are tonight’s entertainment!
 
OB1504
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RE: Rear Bogies Steering!

Wed Jun 07, 2006 12:04 am

The 777 also has this form of steering. The photos don't show it well, but they're the closest I could find in about 1000 shots.


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JBirdAV8r
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RE: Rear Bogies Steering!

Wed Jun 07, 2006 1:13 am

Quoting OB1504 (Reply 6):
The 777 also has this form of steering. The photos don't show it well, but they're the closest I could find in about 1000 shots.

The aft two wheels of each main landing gear assembly are steerable on the 777.
I got my head checked--by a jumbo jet
 
BandA
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RE: Rear Bogies Steering!

Wed Jun 07, 2006 3:10 am

Quoting 777DadandJr (Reply 4):
Quoting UA772IAD (Reply 2):
The answer is quite simple really, and has nothing to do with weight.



Quoting Boeing Nut (Reply 3):
Almost right. The whole design reasoning for the steerable main bogies is to save tearing up the tires and pavement during a phenomenon known as "tire scrub". Saves stress on the gear itself as well.



To add,
It is my understanding that the MLG steering doesn't come into play unless the nose gear is turn more than 20 degrees. I beleive that is what is in one of the books I have at home.

Russ

wow, this is something I never knew... the main land gears actually can steer, is this pretty much standard on large aircraft or an option?
"They [Terrorists] never stop thinking about new ways to harm our country and our people, and neither do we." - GWB
 
777DadandJr
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RE: Rear Bogies Steering!

Wed Jun 07, 2006 3:24 am

Quoting BandA (Reply 8):
wow, this is something I never knew... the main land gears actually can steer, is this pretty much standard on large aircraft or an option?

According to the book that I have at home, and my apologies for not referencing it (I am at the office) shows that the 747 and 777 has this feature from the start.

Russ
My glass is neither 1/2 empty nor 1/2 full, rather, the glass itself is twice as big as it should be.
 
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JBo
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RE: Rear Bogies Steering!

Wed Jun 07, 2006 3:25 am

The C-5 does this as well:


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Tristarsteve
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RE: Rear Bogies Steering!

Wed Jun 07, 2006 3:36 am

Quoting OB1504 (Reply 6):
The 777 also has this form of steering. The photos don't show it well,

I don't think you will see it in a photo. I do push backs on B777 and we go round a 90deg turn onto the taxiway. I was watching from the tug and could not see the rear wheels steering. I know they do because when you sit in the flight deck for a tow you can see them turning on the maint pages.
 
777DadandJr
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RE: Rear Bogies Steering!

Wed Jun 07, 2006 3:54 am

I believe that the AN-225 has steering on it's MLG.(though I have yet to find a picture of it)

Russ
My glass is neither 1/2 empty nor 1/2 full, rather, the glass itself is twice as big as it should be.
 
AsstChiefMark
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RE: Rear Bogies Steering!

Wed Jun 07, 2006 4:36 am

A B-52 can crab its way down a taxiway. It's the goofiest thing I've ever seen. An airplane taxiing diagonally.

Mark
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UA772IAD
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RE: Rear Bogies Steering!

Wed Jun 07, 2006 2:54 pm

Quoting EK413 (Reply 5):
Cheers guys!
I did question where this flight was bound & now that it has been brought to my attention this definately is a runway 25 departure...
Cheers once again

You learn something new here everyday. Check out this article for more on taxiing those behemoths:

http://www.usatoday.com/travel/colum...e/2005-07-18-ask-the-captain_x.htm