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Hydraulic "dust"?  
User currently offlineVSXA380X800 From United Kingdom, joined May 2004, 421 posts, RR: 1
Posted (11 years 9 months ago) and read 2281 times:

Can someone explain this photo to me ?
Look closely at the landing gears......

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Click here for bigger photo!

Photo © Yevgeny Pashnin


4 decks 4 engines 4 long haul
8 replies: All unread, jump to last
User currently offlineNKP S2 From United States of America, joined Dec 1999, 1714 posts, RR: 5
Reply 1, posted (11 years 9 months ago) and read 2270 times:

Carbon dust more likely.

User currently offlineMr.BA From Singapore, joined Sep 2000, 3423 posts, RR: 20
Reply 2, posted (11 years 8 months 4 weeks 1 day 22 hours ago) and read 2146 times:

Upon retraction of the landing gear brakes would be applied automatically to stop the wheels from spinning before it enters the fuselage... Smile So it should be carbon dust as NKP has stated.


Boeing747 万岁!
User currently offlineAuae From United States of America, joined Apr 2004, 296 posts, RR: 3
Reply 3, posted (11 years 8 months 4 weeks 1 day 16 hours ago) and read 1930 times:

?? That is just an illusion in my opinion. You guys sure it just isn't exhaust??

I didn't think the wheels were stopped outside the fuselage either. I thought there was a "stopper" in the wheel well that contacts the tire to stop it.



I will correct myself here. In the 777 sys book it says that the main wheels are indeed stopped prior to entering the wheel well (center hyd sys for all you tech nuts). The front wheels have no brakes, and are stopped when they rub against spin brakes in the nose wheel well.

Looks like the carbon dust is a winner!

[Edited 2004-08-31 14:14:09]

Air transport is just a glorified bus operation. -Michael O'Leary, Ryanair's chief executive
User currently offline320tech From Turks and Caicos Islands, joined May 2004, 491 posts, RR: 5
Reply 4, posted (11 years 8 months 4 weeks 1 day 16 hours ago) and read 1913 times:

Large aircraft usually apply the brakes (automatically in some cases) to stop the wheels before they enter the well. The nose wheels may have an internal contraption to stop them (as on the older A320's - deleted from at least some of the newer ones - not required, I guess).

The primary function of the design engineer is to make things difficult for the manufacturer and impossible for the AME.
User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 66
Reply 5, posted (11 years 8 months 4 weeks 1 day 15 hours ago) and read 1842 times:

At liftoff, the wheels are spinning at high RPM and with the weight suddenly on them, their diameter is somewhat larger than you are accustomed to seeing. As has been stated the mains on most large aircraft are automatically braked before they enter the well. The main gear well on most airliners is home to hydraulic reservoirs and lines, flight control linkage and even fuel lines. Stopping the rotation outside this confined space is a good idea.

Landing gear that retract fore or aft into a well can be stopped with snubbers fitted in the gear well. These stop the rotation by applying friction on the tread surface.

Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineHawk21M From India, joined Jan 2001, 31875 posts, RR: 54
Reply 6, posted (11 years 8 months 4 weeks 1 day 13 hours ago) and read 1815 times:

Auto retract braking is normally used to stop the Main wheels prior to entering the retracted position.The black smoke visable looks like carbon dust.

Think of the brighter side!
User currently offlineAvioniker From United States of America, joined Dec 2001, 1109 posts, RR: 10
Reply 7, posted (11 years 8 months 4 weeks 1 day 13 hours ago) and read 1815 times:

One of the more common systems uses return hydraulic pressure from the retract lines to apply the brakes stopping the main wheels on takeoff. On gear retracting in a straight line the most common is the spin-down brake pads mounted in the top of the wheel well.
The reason is that gear retracting tangentally to the spin direction creates significant side loads due to the gyro effect of the wheel and tire assembly moving or retracting at right angles to the spin direction. Also if the tire is shreadded it will damage the aircraft if it enters the wheel well spinning.

One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
User currently offlineEMBQA From United States of America, joined Oct 2003, 9450 posts, RR: 11
Reply 8, posted (11 years 8 months 4 weeks 1 day 5 hours ago) and read 1770 times:

It's brake dust. There was a thread on this subject just a few weeks ago. Pretty informative.

"It's not the size of the dog in the fight, but the size of the fight in the dog"
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