airfoilsguy
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Are There Brakes On The Nose Gear?

Tue Jan 24, 2006 10:16 am

I don't seem to recall seeing break rotors on the nose gear of most aircraft. If they don't have breaks on the nose gear, why not? Wouldn't that help reduce stopping distance. I know cars use the front wheels for a majority of their stopping power.
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Jetlagged
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Are There Brakes On The Nose Gear?

Tue Jan 24, 2006 10:24 am

The nose gear only takes about 10% of the aircraft's weight, so can't provide much braking force. There have been a few airliners with nosewheel brakes (some 727s had them). Generally they aren't seen as being worth the weight penalty.

I'd guess the front wheels of a car might be taking 60% or more of the weight of the car under heavy braking, which is why they provide most of the braking force.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
airfoilsguy
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Are There Brakes On The Nose Gear?

Tue Jan 24, 2006 10:35 am

Quoting Jetlagged (Reply 1):
I'd guess the front wheels of a car might be taking 60% or more of the weight of the car under heavy braking, which is why they provide most of the braking force.

My though was that once breaking action started the center of gravity shifts toward the front of the plane, thus putting a greater percentage of the aircrafts weight forward.
It's not a near miss it's a near hit!!
 
2H4
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Are There Brakes On The Nose Gear?

Tue Jan 24, 2006 10:56 am



Convairs had them, too:




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OPNLguy
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Are There Brakes On The Nose Gear?

Tue Jan 24, 2006 11:05 am

Quoting Airfoilsguy (Thread starter):
Are There Breaks On The Nose Gear?

Only if the pushback tug hits the nose gear really hard...

Brakes on the other hand...  Wink
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
 
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HAWK21M
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Are There Brakes On The Nose Gear?

Tue Jan 24, 2006 6:44 pm

Since the Main Gear brakes take most of the Aircraft Weight.It makes sense to have them Installed there.On the B727 there were NLG brakes.
Cannot locate a pic though.
If the purpose can be served by The Main Gear brakes alone,the Weight savings along with the Mechanical complications can be avoided.
Also the NLG Brakes were effective only after approx 60% of the Main Brake application as I was told.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
LH4U
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Are There Brakes On The Nose Gear?

Wed Jan 25, 2006 1:41 am

Quoting Airfoilsguy (Reply 2):
My though was that once breaking action started the center of gravity shifts toward the front of the plane, thus putting a greater percentage of the aircrafts weight forward.

Center of gravity doesn´t move when braking.... it´s only dependent on weight ditribution. The main wheels are almost always behind CoG, so when main gear braking starts, there will be a momentum on the nose gear. That´s probably what you mean. But still, with this momentum nose gear braking would have relatively little effect...

Greets
 
2H4
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Are There Brakes On The Nose Gear?

Wed Jan 25, 2006 1:44 am



I just found this quote from http://www.b737.org.uk, referring to the 737-200ADV:

Autobrake, improved anti-skid, automatic speedbrake for RTO, automatic performance reserve and even nose-brakes became available.

This is the first I've heard of nosewheel brakes being offered on the 737. Were any actually installed?




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Jetlagged
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Are There Brakes On The Nose Gear?

Wed Jan 25, 2006 1:44 am

Quoting Airfoilsguy (Reply 2):
My though was that once breaking action started the center of gravity shifts toward the front of the plane, thus putting a greater percentage of the aircrafts weight forward.

Still its a very small percentage on a small contact area. The vast majority of the aircraft's weight stays on the main wheels, even under braking. Also, the nosewheel tyres have enough work to do with nosewheel steering.

Car tyres start with roughly 50/50 fore/aft weight split (maybe 55/45 allowing for the engine). Braking g loads further increase this imbalance. In an aircraft, to transfer significant weight forward onto the nosewheel would required dramatic deceleration rates, which might not go down too well with the self loading cargo.
The glass isn't half empty, or half full, it's twice as big as it needs to be.
 
CosmicCruiser
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Are There Brakes On The Nose Gear?

Wed Jan 25, 2006 2:37 am

Fedex had all the nose gear brakes removed on our 727s years ago.
 
Elvisisalive
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Are There Brakes On The Nose Gear?

Wed Jan 25, 2006 5:40 am

Am pretty sure all the wheels on the 747-400 nose or main are the 3-1479-2
so if the -400 does not have nose brakes is there just a cavity in the wheel were the brake would be ?
 
FredT
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Are There Brakes On The Nose Gear?

Wed Jan 25, 2006 5:56 am

Quoting Jetlagged (Reply 1):
Generally they aren't seen as being worth the weight penalty.

Not to mention maintenance!

Quoting Airfoilsguy (Reply 2):
My though was that once breaking action started the center of gravity shifts toward the front of the plane, thus putting a greater percentage of the aircrafts weight forward.

The center of gravity stays put, but the weight distribution among the wheels is changed by the torque generated by the braking force.

The Saab Gripen has nose wheel braking. Makes for a lot of stopping power, combined with lift dumping, canards doubling as giant airbrakes and anti-lock brakes that can be applied prior to touchdown. Hardly an airliner though...  Smile

So, who will be first to estimate the force on the nose wheels of an airliner during braking?

Cheers,
Fred
I thought I was doing good trying to avoid those airport hotels... and look at me now.
 
Matt72033
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Are There Brakes On The Nose Gear?

Wed Jan 25, 2006 6:01 am

Quoting Elvisisalive (Reply 10):
Am pretty sure all the wheels on the 747-400 nose or main are the 3-1479-2
so if the -400 does not have nose brakes is there just a cavity in the wheel were the brake would be ?

no brakes on the nosewheel of a 744
 
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HAWK21M
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RE: Are There Brakes On The Nose Gear?

Wed Jan 25, 2006 2:54 pm

Quoting 2H4 (Reply 7):
This is the first I've heard of nosewheel brakes being offered on the 737. Were any actually installed

I heard on this forum someplace that it was an option.Although have never personally noticed a B737 equipped with NLG brakes.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
saintsman
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RE: Are There Brakes On The Nose Gear?

Wed Jan 25, 2006 4:49 pm

There are brakes fitted to some aircraft to stop the wheels spinning after they have been retracted. They are applied directly to the tyres.
 
Matt72033
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RE: Are There Brakes On The Nose Gear?

Wed Jan 25, 2006 7:44 pm

Quoting Matt72033 (Reply 12):
Quoting Elvisisalive (Reply 10):
Am pretty sure all the wheels on the 747-400 nose or main are the 3-1479-2
so if the -400 does not have nose brakes is there just a cavity in the wheel were the brake would be ?

no brakes on the nosewheel of a 744

but your right, i checked, and the part numbers are interchangeable!
 
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HAWK21M
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RE: Are There Brakes On The Nose Gear?

Thu Jan 26, 2006 12:20 am

Quoting Saintsman (Reply 14):
There are brakes fitted to some aircraft to stop the wheels spinning after they have been retracted. They are applied directly to the tyres

http://www.b737.org.uk/wheelwellnose_ng_labelled.jpg
They are referred to as Snubber pads.The above pic does not depict the total pads though,the Aft section is visable.Will post a better one when available later.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
Gunships
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RE: Are There Brakes On The Nose Gear?

Thu Jan 26, 2006 11:07 am

Quoting Saintsman (Reply 14):
There are brakes fitted to some aircraft to stop the wheels spinning after they have been retracted. They are applied directly to the tyres.

We used to call them "spin brakes" on the C-141. Just static brake pads installed near the top of the NLG wheel well that the NLG tires would contact as they retracted.

Eliminated the "gyro" effect of the tires spinning, which would add an unecessary force to an already heavily-stressed structure.

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