ERJ145LR
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What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 7:24 am


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--what is that black thing attached to the front gear of this 717, do they all have it?
 
SPREE34
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 7:26 am

Spray deflector. Keeps water from spraying out and up into the engines. So I was told.
I don't understand everything I don't know about this.
 
mtnmanmakalu
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 7:29 am

SPREE34-
You are right-
It also keeps snow and slush and ice, along with water from going into the engines....

mtnman
I do, I don't, whatever.......
 
ERJ145LR
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 7:30 am

thats all the way on the front nose gear how would it keep snow, water etc, from getting in the engines..all the way on the back of the plae???
 
mtnmanmakalu
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 7:35 am

thats all the way on the front nose gear how would it keep snow, water etc, from getting in the engines..all the way on the back of the plae???

I suggest you take an Aerospace class (which I have) or something along those lines and maybe you can see how it would.
You evidently don't live in a "snow belt" or you would know what slush spray is like...
I do, I don't, whatever.......
 
flybyguy
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 7:36 am

It protects the belly from being damaged by small runway debris like pebbles etc. The DC-9/717 type aircraft are built to sit very low to the ground so such a device is necessary to mitigate any potential damage.
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ERJ145LR
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 7:49 am

ok, thanks for a NICE answer Flybyguy. mmmhhmmm mtnmanmakalu
 
Av8trxx
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 8:10 am

Yes, it was a nice post wasn't it? According to the Boeing site, the optional deflectors on the 717, MD80 & MD90 are combination spray and FOD deflectors. Water spray off the nosewheel does get back up to the tail mounted engines even though one might not think it would. Instead of an arrogant reply like #4, a picture is worth a thousand words and will help one understand better. The pix on this link are some great illustrations, the 727 at bottom in peticular-
http://www.airdisaster.com/forums/showthread.php?t=60937&page=2&pp=10
 
JeffLAS
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 10:42 am


Remember Nordair? All of their 737's had the deflector thing on the front gear as well. They very much earned their usefulness on some of the gravel runways in northern Canada. Pacific Western Airlines had them on their 737's for airports such as Fort McMurray in the early 70's. (Alberta, Canada, in case you are wondering where it is, home to 1.4 trillion barrels of oil.) (YES, Trillion) : Big thumbs up
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flyabunch
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 10:57 am

I also recall seeing Alaska 737-200's at SEA with a rod sticking out in front of the bottom of the engine nacelle. I was told that it was positioned to prevent rocks from being sucked into the engine on gravel airstrips. When you look at the moisture vortexes on the link in reply 7 it sure makes sense.

Mike
 
L-188
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 11:08 am

Spray guard.

Micky-D thought it would be a cheaper solution to keep water spray out of the engines then what Boeing did on the 727, which was used Chined tires on the NLG.
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LVZXV
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 11:18 am

thats all the way on the front nose gear how would it keep snow, water etc, from getting in the engines..all the way on the back of the plae???


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The main gear are also fitted with deflectors to guard against FOD. Ironically, the aircraft in the second picture sustained considerable damage last February when one of its left main-wheels separated on take-off, damaging a flap and the #1 engine (not sure if this occurred in the actual incident or during the emergency landing at EZE when the remaining tyre on that assembly blew-out).


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Regards,

ZXV

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meister808
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 12:11 pm

From those Aerolineas Argentinas pictures, are there deflectors on the main landing gear as well?

-Meister
Twin Cessna 812 Victor, Minneapolis Center, we observe your operation in the immediate vicinity of extreme precipitation
 
stirling
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 1:15 pm

I thought the rod coming out from under the engine nacelles was actually a nozzle that shot high pressure bleed air down and out, in front of the engine, spraying any loose objex out of the way, as a protection from FOD (Foreign Object Damage).

I always wondered how that could over-power the intake forces?
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747NUT
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RE: What Is The Thing Attached To The Front Gear?

Thu Jan 13, 2005 8:26 pm

I always wondered how that could over-power the intake forces?

It does not over-power the forces as such, it just prevents the formation of a vortex, or mini tornado, for lack of a better word. Which will pick up FOD from the ground.

Hope that helps
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HAWK21M
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RE: What Is The Thing Attached To The Front Gear?

Fri Jan 14, 2005 2:11 am

Would the correct term be 'Gravel Deflector'
On the B737 it was called that,& the Tube projecting below the Engine was the Vortex Dissapator.I guess the Name explains it all.
regds
MEL
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SATL382G
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RE: What Is The Thing Attached To The Front Gear?

Fri Jan 14, 2005 2:30 am

I've got a video of Boeings high speed taxi water ingestion test for the 727.
Video was shot from the some height at the end of the runway and facing the nose. Difference between chined & non-chined tires was dramatic. The chine really does the job....
"There’s nothing quite as exhilarating as being shot at and missed" --Winston Churchill
 
LVZXV
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RE: What Is The Thing Attached To The Front Gear?

Fri Jan 14, 2005 3:11 am

Meister:

From those Aerolineas Argentinas pictures, are there deflectors on the main landing gear as well?

Indeed there are.  Smile

Regards,

ZXV

How do you say "12 months" in Estonian?
 
SlamClick
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RE: What Is The Thing Attached To The Front Gear?

Fri Jan 14, 2005 5:05 am

Couple of notes:

Earlier (shorter) DC-9 aircraft did use chined tires on the nosewheel.

The spray deflector on the MD-80 nose gear required a new towbar because it was about an inch wider. I believe the newer towbars could also handle the earlier nines.

* * *


Erj145er how it gets all the way back to the engines is really pretty clear if you think in terms of time rather than distance. The nosewheel throws up a roostertail of water or slush, throwing out to the sides, maybe 15 or 20 feet in the air - and it moves on. It takes the water a second or so to fly up that high and fall back to the runway, but during that second or so, the engines have arrived on the scene. By 88 knots, the MD-80 is traveling its own length each second and it is accelerating.


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L-188
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RE: What Is The Thing Attached To The Front Gear?

Fri Jan 14, 2005 5:36 am

I've got a video of Boeings high speed taxi water ingestion test for the 727.
Video was shot from the some height at the end of the runway and facing the nose. Difference between chined & non-chined tires was dramatic. The chine really does the job....


I have a copy of that video too, too bad I can't put it on the web.

Makes a great impression on how much more soaked the engines get without the chines.
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meister808
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RE: What Is The Thing Attached To The Front Gear?

Fri Jan 14, 2005 8:45 am

What is a chine?

-Meister
Twin Cessna 812 Victor, Minneapolis Center, we observe your operation in the immediate vicinity of extreme precipitation
 
242
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RE: What Is The Thing Attached To The Front Gear?

Fri Jan 14, 2005 9:07 am

Douglas has water ingestion video footage for the MD80 series. It may seem unlikely, but at speed without some kind of deflector/chine on the nose gear, water goes directly from the nose wheels, over the wing, and in to the engines.
 
2H4
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RE: What Is The Thing Attached To The Front Gear?

Fri Jan 14, 2005 9:17 am




This shot is pretty small, but it's all I could find.


2H4
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SlamClick
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RE: What Is The Thing Attached To The Front Gear?

Fri Jan 14, 2005 9:52 am

Meister808 a chine is similar to a strake or a fence. DC-9 nosewheel tires had one, a high thin rubber ridge that ran all the way around the outboard side of the tire.

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Neither of these pictures show it very well, but it can be seen here.
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2H4
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RE: What Is The Thing Attached To The Front Gear?

Fri Jan 14, 2005 1:42 pm

Here's another shot:




The tire on the left would be used for aircraft with two nosewheels, like a 727, where each tire has a single chine on the outside. The tire on the right would be used for aircraft with a single nosewheel, such as a early Citation or Learjet.


2H4
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