bio15
Posts: 1048
Joined: Fri Mar 23, 2001 8:10 am

What's This Carcass Over The ERJ-145 Main Wheel?

Wed Mar 30, 2005 10:44 am

I noticed that the ERJ 145 has a sort of carcass over one of the two main tires on each assembly. Judging from the pictures, it seems to rotate over the wheel depending on whether the aircraft is airborne or not. I was thinking that it is some sort of FOD protector for the tires, is this assumption correct? If so, why does it rotate?

Here are the pictures

Carcass down:

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Photo © Daniel & Robert Fall
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Photo © Paul Robbins



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Photo © Frische Michael
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Photo © Jid Webb



Carcass up:

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Photo © Daniel Evans
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Photo © Stuart Haigh



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Photo © Justin Wood




Alfredo


edit: typos..

[Edited 2005-03-30 02:46:48]
 
troubleshooter
Posts: 420
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RE: What's This Carcass Over The ERJ-145 Main Wheel?

Wed Mar 30, 2005 11:24 am

Just have a look here: http://www.airliners.net/discussions/tech_ops/read.main/113566/
You are talking about the auxiliary gear door. As it is fixed to the landing gear leg, it is not moving. When the aircraft is airborne, the strut extends and the relative position of the wheels to that door has changed. That´s why you think it rotates. Look at the link above. There you´ll find it.
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TWAMD-80
Posts: 962
Joined: Tue Oct 16, 2001 8:25 am

RE: What's This Carcass Over The ERJ-145 Main Wheel?

Wed Mar 30, 2005 11:28 am

Interesting, I don't think I have seen that before. To me it looks like part of the landing gear cover. Also, the ERJ-145 series uses a trailing-link landing gear, which would help explain the change of position seen when the gear is compressed and uncompressed. When I first saw the topic of this post, I though the ERJ ran over some roadkill  laughing .

TW
Two A-4's, left ten o'clock level continue left turn!
 
troubleshooter
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RE: What's This Carcass Over The ERJ-145 Main Wheel?

Wed Mar 30, 2005 11:42 am

Quoting TWAMD-80 (Reply 2):
To me it looks like part of the landing gear cover

Actually, it is part of the landing gear cover...  Wink
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bio15
Posts: 1048
Joined: Fri Mar 23, 2001 8:10 am

RE: What's This Carcass Over The ERJ-145 Main Wheel?

Wed Mar 30, 2005 12:35 pm

Hi Troubleshooter, thanks for your response. Now I know this is an auxiliary gear door, not an FOD protection element as I thought  Smile. I saw your response on the other thread, it's clear how this auxiliary door goes flush with the fuselage to complete the missing area of the main gear door, which is the flat rectangular door. It's necessary to fit the part that has the curvature of the belly border.

However, I still see that the angle position of the auxiliary gear door changes when the aircraft is on the ground. Here are some pictures that illustrate this clearly:


Ground position: The upper part of the door (the small rectangular part perpendicular to the ground) is 'facing down'. In other words, the left border is not straight, but instead it is angled to the left from the vertical position.

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Photo © Robert Flinzner
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Photo © Daniel Wojdylo



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Photo © H. Meier
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Photo © Patrick Mutzenberg



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Photo © Christophe Weber



Airborne position: The upper rectangular part of the auxiliary gear door has the left border vertical.

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Photo © John Davies - CYOW Airport Watch
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Photo © John Davies - CYOW Airport Watch



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Photo © Daniel Wojdylo
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Photo © Gary Stewart



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Photo © Shenzhe



Based on the images, I would say that the auxiliary gear door is moving together with the tires, and that it rotates forward when the strut compresses. I am just basing myself on the pictures, not playing smartass!  Smile I hope I was clear on my typing

Alfredo
 
bio15
Posts: 1048
Joined: Fri Mar 23, 2001 8:10 am

RE: What's This Carcass Over The ERJ-145 Main Wheel?

Wed Mar 30, 2005 12:49 pm

Hi Tim, after reading your reply I went for the dictionary and found out the other meaning of carcass, which I was unaware of:

car-cass n 1: a dead body; esp the dressed body of a meat animal 2: the living body 3: the foundation structure of something (as a tire)  expressionless 

In spanish we use this word to refer specifically to the third definition, not to any of the first too. My mistake!

Sorry if this led to confussions!  Smile

Alfredo
 
TWAMD-80
Posts: 962
Joined: Tue Oct 16, 2001 8:25 am

RE: What's This Carcass Over The ERJ-145 Main Wheel?

Wed Mar 30, 2005 2:02 pm

Alfredo, not a problem at all, I got a laugh out of it! I learned something new - 3: the foundation structure of something (as a tire).

TW
Two A-4's, left ten o'clock level continue left turn!
 
troubleshooter
Posts: 420
Joined: Mon Feb 07, 2005 5:22 am

RE: What's This Carcass Over The ERJ-145 Main Wheel?

Thu Mar 31, 2005 2:36 am

Quoting Bio15 (Reply 4):
However, I still see that the angle position of the auxiliary gear door changes when the aircraft is on the ground

Hi Alfredo,

none of the doors changes it´s position as both are fixed to the main landing gear leg. The main door is hinged to rotate during gear retraction.

The wheels change their relative position to the auxiliary door as a result of a different position of the main gear trailing arm due to an extended strut. The auxiliary gear door is completely fixed to the gear leg and doesn´t move with strut extension.
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bio15
Posts: 1048
Joined: Fri Mar 23, 2001 8:10 am

RE: What's This Carcass Over The ERJ-145 Main Wheel?

Thu Mar 31, 2005 8:41 am

Quoting Troubleshooter (Reply 7):
none of the doors changes it´s position as both are fixed to the main landing gear leg. The main door is hinged to rotate during gear retraction.

Hi Troubleshooter. I see that the auxiliary gear door is fixed to the lower gear leg, but not the upper, thus it may seem to rotate. The gear leg does change it's angular position when it's on the ground because it flexes to work as suspension for the aircraft, and moves along with the auxiliary gear door, that's why I say it "rotates". I elaborated a diagram to show what I am saying.



I'm feeling bad because I may sound as trying to contradict you, but it is not at all that way. I saw nearly 200 photos in the database, and they all show this behavior I put on the diagram. I'm thinking we're both probably saying the same thing, but I'm not understanding your way of putting it into words, or I've gone competely stupid & blind this time! Please excuse me in any case for being a pain in the ass.


Regards
Alfredo
 
meister808
Posts: 924
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RE: What's This Carcass Over The ERJ-145 Main Wheel?

Fri Apr 01, 2005 3:38 pm

I'm with Alfredo on this one, unless, like he, I have gone completely blind and stupid. That door rotates with the rotation of the trailing-linkage suspension.

Interesting that they even put this part on, though, because it has been demonstrated on many, many airplanes(the B737 comes to mind instantly) that there really isn't a need to have a cover over this part of the gear while the airplane is in flight. It seems like Embraer is overly complicating the issue for a minimal gain.

-Meister
Twin Cessna 812 Victor, Minneapolis Center, we observe your operation in the immediate vicinity of extreme precipitation
 
troubleshooter
Posts: 420
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RE: What's This Carcass Over The ERJ-145 Main Wheel?

Fri Apr 01, 2005 7:14 pm

Quoting Bio15 (Reply 8):
I see that the auxiliary gear door is fixed to the lower gear leg, but not the upper

I had a brief look at the AMM this morning. The auxiliary gear door is attached to the trailing arm axle. So it moves during strut extension with the trailing arm. I was a bit wrong on that as I was thinking it is fixed to the gear leg.

Quoting Bio15 (Reply 8):
I'm feeling bad because I may sound as trying to contradict you, but it is not at all that way.

You don´t have to feel bad, because you are right. I didn´t want to attack you, so I have to apologize if you thought that.

I hope the question is answered now. Thanks for this good discussion!
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