Ferret
Topic Author
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Spray Deflector On B717, MD80s And MD90s?

Sat Aug 26, 2006 5:21 am

I have often seen the strange appendage to the nose gear of the Boeing 717s, MD-80s and MD-90s. It has been identified as a spray deflector.

I am curious why this is needed and why this is the only airframe that seems to need it. I would guess it is to prevent water spray ingestion into the engines, but it seems like that wouldn't be a problem for tail-mounted engines.

Any insight is appreciated.  Smile


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twal1011727
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RE: Spray Deflector On B717, MD80s And MD90s?

Sat Aug 26, 2006 5:39 am

This has been discussed before.....

It is to help keep FOD from getting slung up over the wings into the engines. Yes...it does happen.

The B727 had chined nose gear tires to do the same job.
Do a B727 A/C search and look at some pictures and you'll see them.

KD
 
BH
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RE: Spray Deflector On B717, MD80s And MD90s?

Sat Aug 26, 2006 11:48 am

You hit the nail on the head of it's use. Recent test have concluded that thier is really no difference on the spray of water with or without the spray deflector.You may start seeing the trend of some of the airlines taking them off.It is also saves a bit of wieght (i guess not that much,but every bit helps).It also saves time on the replacement of the nose gear tires.

From what i am told by the MX guys in the field they take a hell of a beating and always have to be cared for.The Back spray deflectors will stay on.
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CaptRightseat
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RE: Spray Deflector On B717, MD80s And MD90s?

Sat Aug 26, 2006 12:05 pm

What is the approximate weight of the part?
 
 
dogfighter2111
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RE: Spray Deflector On B717, MD80s And MD90s?

Sat Aug 26, 2006 10:09 pm

Didn't Concorde have these fitted after the fatal AF Concorde crash, and if so I take it that it was for the same use?

Thanks
Mike
 
2H4
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RE: Spray Deflector On B717, MD80s And MD90s?

Sat Aug 26, 2006 10:55 pm




Quoting Dogfighter2111 (Reply 5):
Didn't Concorde have these fitted after the fatal AF Concorde crash, and if so I take it that it was for the same use?

I believe the purpose of the Concorde's devices was to contain tire debris in the event of a puncture.




2H4


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HAWK21M
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RE: Spray Deflector On B717, MD80s And MD90s?

Sat Aug 26, 2006 10:57 pm

Quoting Dogfighter2111 (Reply 5):
Didn't Concorde have these fitted after the fatal AF Concorde

http://www.findarticles.com/p/articl...m0CWU/is_2000_August_4/ai_63866114
The Link states it was a possible cause in the 90s.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
dogfighter2111
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RE: Spray Deflector On B717, MD80s And MD90s?

Sat Aug 26, 2006 11:28 pm

Thanks for the info guys,

I was unaware that Concorde was fitted with these prior to the incident. I take it that work was carried out on these after the AF crash. The reason I say that is, that previously I was watching BBC News when Concorde was re-introduced and the new modifications list had the Deflectors on that list.

Thanks
Mike
 
David L
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RE: Spray Deflector On B717, MD80s And MD90s?

Sun Aug 27, 2006 12:10 am

Quoting 2H4 (Reply 6):
Quoting Dogfighter2111 (Reply 5):
Didn't Concorde have these fitted after the fatal AF Concorde crash, and if so I take it that it was for the same use?

I believe the purpose of the Concorde's devices was to contain tire debris in the event of a puncture.

I think they were spray deflectors and made of glass fibre but later reinforced with something like steel bands to reduce the effects of shattering in the event of a burst tyre.
 
vc10
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RE: Spray Deflector On B717, MD80s And MD90s?

Sun Aug 27, 2006 4:44 am

Concorde had water deflectors fitted to the main landing gear and to the nose gear, and they were there to control water from the wheels. They were fitted all the time the aircraft were in service, ie 1976 onwards.

After an incident I believe in the 1980s a recommendation was made that the Main Wheel water deflectors should be strenghtened with metal reinforcing. This was only a recommendation and BA took it up.

Interestingly another rear engine aircraft, the VC-10, had rubber chines moulded into the wall of it's nose wheel tyres, again to try and suppress the water wave from these tyre, and so prevent water injestion by the engines.

littlevc10

[Edited 2006-08-26 21:46:59]
 
David L
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RE: Spray Deflector On B717, MD80s And MD90s?

Sun Aug 27, 2006 5:21 am

Quoting VC10 (Reply 10):
They were fitted all the time the aircraft were in service, ie 1976 onwards.

I neglected to specify that. That was the whole point of my post. D'oh!
 
Filton
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RE: Spray Deflector On B717, MD80s And MD90s?

Mon May 12, 2008 9:36 pm

Nose wheel spray deflectors have been discussed quite a lot, but not so much main gear deflectors, such as these on the MD90:


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If they are to prevent spray/debris getting into the engine, why don't all rear engined aircraft have them?

I'm also interested in how they attach. Does anyone have any more detailed pictures - or perhaps a drawing from a maintenance manual?

Thanks...
 
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Starlionblue
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RE: Spray Deflector On B717, MD80s And MD90s?

Mon May 12, 2008 11:06 pm



Quoting Filton (Reply 12):
If they are to prevent spray/debris getting into the engine, why don't all rear engined aircraft have them?

My guess is because all aircraft are slightly different and the debris trajectory varies.

Also as mentioned, the 727 has chines, which do the same things but in a different way.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Filton
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RE: Spray Deflector On B717, MD80s And MD90s?

Tue May 13, 2008 4:46 pm



Quoting Starlionblue (Reply 13):
My guess is because all aircraft are slightly different and the debris trajectory varies.

That makes sense, but it is one thing to have difference layouts of deflectors, as in the DC 9 & MD80, but quite another not to have any at all, like Fokker 70 etc.

Anyone know what these deflectors are made of? They look like pretty chunky lumps of metal to me - must be very heavy. Someone must have a close up pic!
 
Dalmd88
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RE: Spray Deflector On B717, MD80s And MD90s?

Wed May 14, 2008 7:36 am



Quoting Filton (Reply 14):
Anyone know what these deflectors are made of? They look like pretty chunky lumps of metal to me - must be very heavy. Someone must have a close up pic

They are made of AL. They are a lot lighter than they look because of that. Most guys I work with hate changing a MD80 nose tire because of the added hassle of the deflector. It isn't that much more work, only two bolts in the back and the one on the axle. Most guys I think are just looking for something to bitch about. Hell, you don't even need to jack the gear. Simply turning the nose gear on a MadDog gets the tire off the ground.

There is also a little spray deflector on the main gear. It's just this batwing looking strip aft of the tires.
 
777wt
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RE: Spray Deflector On B717, MD80s And MD90s?

Sat May 17, 2008 10:21 pm

BH,

your images shows up with a red X.

Can you host it again?
 
josekmlb
Posts: 195
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RE: Spray Deflector On B717, MD80s And MD90s?

Wed Jun 25, 2008 4:51 am



Quoting TWAL1011727 (Reply 1):
It is to help keep FOD from getting slung up over the wings into the engines. Yes...it does happen.

I was thinking the same thing.

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