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Rear Bogies Steering!  
User currently offlineEK413 From Australia, joined Nov 2003, 4919 posts, RR: 4
Posted (8 years 3 months 2 weeks 2 days 5 hours ago) and read 2423 times:

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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Photo © JumboJim747



Enjoy!!! Big grin



EK413


Good evening, ladies and gentlemen. We are tonight’s entertainment!
14 replies: All unread, jump to last
 
User currently offlineStealthZ From Australia, joined Feb 2005, 5696 posts, RR: 44
Reply 1, posted (8 years 3 months 2 weeks 2 days 5 hours ago) and read 2396 times:
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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!
User currently offlineUA772IAD From Australia, joined Jul 2004, 1730 posts, RR: 3
Reply 2, posted (8 years 3 months 2 weeks 2 days 5 hours ago) and read 2385 times:

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.

User currently offlineBoeing Nut From , joined Dec 1969, posts, RR:
Reply 3, posted (8 years 3 months 2 weeks 1 day 21 hours ago) and read 2248 times:

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


User currently offline777DadandJr From United States of America, joined Feb 2005, 1516 posts, RR: 12
Reply 4, posted (8 years 3 months 2 weeks 1 day 20 hours ago) and read 2203 times:

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.
User currently offlineEK413 From Australia, joined Nov 2003, 4919 posts, RR: 4
Reply 5, posted (8 years 3 months 2 weeks 1 day 20 hours ago) and read 2172 times:

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!
User currently offlineOB1504 From United States of America, joined Jul 2004, 3354 posts, RR: 6
Reply 6, posted (8 years 3 months 2 weeks 1 day 19 hours ago) and read 2143 times:

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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Photo © Fabian Gysel
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Photo © John Harris



User currently offlineJBirdAV8r From United States of America, joined Jun 2001, 4490 posts, RR: 21
Reply 7, posted (8 years 3 months 2 weeks 1 day 18 hours ago) and read 2060 times:

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
User currently offlineBandA From United States of America, joined Aug 2004, 338 posts, RR: 0
Reply 8, posted (8 years 3 months 2 weeks 1 day 16 hours ago) and read 1972 times:

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
User currently offline777DadandJr From United States of America, joined Feb 2005, 1516 posts, RR: 12
Reply 9, posted (8 years 3 months 2 weeks 1 day 16 hours ago) and read 1942 times:

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.
User currently offlineJBo From Sweden, joined Jan 2005, 2343 posts, RR: 0
Reply 10, posted (8 years 3 months 2 weeks 1 day 16 hours ago) and read 1942 times:

The C-5 does this as well:


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Photo © Tom Houquet
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Photo © Bjorn van der Velpen




I'd take the awe of understanding over the awe of ignorance any day.
User currently offlineTristarsteve From Sweden, joined Nov 2005, 4008 posts, RR: 33
Reply 11, posted (8 years 3 months 2 weeks 1 day 16 hours ago) and read 1911 times:

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.


User currently offline777DadandJr From United States of America, joined Feb 2005, 1516 posts, RR: 12
Reply 12, posted (8 years 3 months 2 weeks 1 day 16 hours ago) and read 1889 times:

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.
User currently offlineAsstChiefMark From , joined Dec 1969, posts, RR:
Reply 13, posted (8 years 3 months 2 weeks 1 day 15 hours ago) and read 1826 times:

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

Mark


User currently offlineUA772IAD From Australia, joined Jul 2004, 1730 posts, RR: 3
Reply 14, posted (8 years 3 months 2 weeks 1 day 5 hours ago) and read 1676 times:

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


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