USairways16BWI
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Noise On 757 Take-off

Sat Sep 10, 2005 1:56 pm

Everytime I fly on a 757, there is a loud bump just as the plane lifts off the ground...it sounds like its coming from the main gear, or somewhere underneath the plane. Anyone know what it is?
 
AJ
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RE: Noise On 757 Take-off

Sat Sep 10, 2005 2:06 pm

Probably just the oleos fully extending and the bogeys tilting on the main gear.
 
320tech
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RE: Noise On 757 Take-off

Sat Sep 10, 2005 2:07 pm

Not having had the privilege of having flown on a 757, I can only surmise that it's the bogies dropping into the retraction position (ie, leading wheels up).
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MX757
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RE: Noise On 757 Take-off

Sat Sep 10, 2005 2:25 pm

After rotation the main gear shock struts go to full extend. And the forward part the truck-the front axle with the front wheels on it- tilts up. That could be the "bump" you are hearing.
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HAWK21M
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RE: Noise On 757 Take-off

Sun Sep 11, 2005 12:31 am


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Def the Bogies Dropping to the Tilted position & Extension of the Oleos.
regds
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dl757md
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RE: Noise On 757 Take-off

Sun Sep 11, 2005 4:45 am

I concur with the explanations above. The truck tilt actuator has 3000psi hydraulic fluid acting on it and it pretty severly rams the truck to it's tilt position against the stops. When the truck hits those stops that hard it's going to make a pretty loud thump. No problems though as they where designed for this.

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HAWK21M
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RE: Noise On 757 Take-off

Sun Sep 11, 2005 12:38 pm

Quoting Dl757md (Reply 5):
The truck tilt actuator

Any Close up Photos on this Actuator.
regds
MEL
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garpd
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RE: Noise On 757 Take-off

Sun Sep 11, 2005 11:59 pm

Hmm, I've never actually noticed such a noise in my several 757 flights.

I'm generaly more tuned into listening to the fabulous sound of the RB211s on take off power.... ooo baby  Wink
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tinpusher007
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RE: Noise On 757 Take-off

Mon Sep 12, 2005 5:01 am

Quoting GARPD (Reply 7):
I'm generaly more tuned into listening to the fabulous sound of the RB211s on take off power.... ooo baby

I concur....but I also love the sound of those bogeys slamming into place after rotation...sounds powerful.
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khenleydia
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RE: Noise On 757 Take-off

Sun Sep 18, 2005 3:09 am

From what I have noticed, if you listen for it, you will hear that on most major commercial airplanes. Maybe I should say, anything larger then a 737 or A320.

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