Just a curious question, but whilst I was waiting for the bus to take me from the staff car park to the terminal at LGW this morning, I watched two wide-body aircraft land within a couple of minutes of each other, but I noticed that when the first one ‘flared’ just before its wheels touched the runway, they were angled upwards, but when the second aircraft came in, its wheels were angled downwards, can anyone (a commerical pilot preferably!) offer an explaination as to why this is and why it is done?
By: wysiwyg - 16th April 2007 at 14:35
It is purely done to facilitate stowage in the wells and the retraction sequence. If you look at the A340-600 you’ll see that the main gears tilt a different way to the centre gear. This is to allow the mainwheels to clear the center bogey during the retraction.
By: rdc1000 - 13th April 2007 at 16:30
OK,
A couple of links for you. The first is a US Patent regarding landing gears on Large Aircraft with rear Centre of Gravity
http://www.patentstorm.us/patents/5086995-description.html
Nothing much to see, though it refers to the B767 as an example.
The second is a thing on airliners.net (from a google search). Near the end, two poster’s Mendor, and DH106 seem to explain it between them..
http://www.airliners.net/discussions/tech_ops/read.main/11948/
By: rdc1000 - 13th April 2007 at 16:07
It is simply the way the retracted bogey fits into the fuselage, the 767’s angles downwards for this reason and was designed as such to enable the bogey to fit within the fuselage. It is not a pilot selected option or for aerodynamics or another reason.
I thought on the 767 that it was actually a centre of gravity issue based on where the undercarriage is, and that if the bogey hung in the same way as all other aircraft the COG would be pushed too far back? I could be wrong, but for years that has been my understanding given things I had read, I can’t remember the source(s) of this piece of knowledge, I’ll do a search…as I say I could be (and probably am) wrong.
By: Agent K - 13th April 2007 at 15:57
It is simply the way the retracted bogey fits into the fuselage, the 767’s angles downwards for this reason and was designed as such to enable the bogey to fit within the fuselage. It is not a pilot selected option or for aerodynamics or another reason.
By: David2386 - 13th April 2007 at 15:50
Were they the same type?
The underdcarriage on different types sits differently, like below. 767 is angled but 747 is /
http://www.airliners.net/open.file/1198083/L/
http://www.airliners.net/open.file/1197579/L/
I can’t remember the reason but I think it was something to do with how its stowed, and cannot be altered by the crew. I’m sure someone more knowledgeable though will correct me though.
By: SHAMROCK321 - 13th April 2007 at 15:50
I dont think there is much of an expanation to be given. I think its just the way the end up, then again I could be wrong.
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April 13, 2007 at 3:42 pm