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-   -   727 Nose Wheel Brakes (https://www.pprune.org/tech-log/406335-727-nose-wheel-brakes.html)

galaxy flyer 23rd Feb 2010 02:43

Spooky 2

EAL had NWB on the earlier planes, but I don't think -200A had NWB. I got there in 84 and all the NWBs had been removed from the 125-strong fleet.

GF

Dan Winterland 23rd Feb 2010 06:25

I think the Convair jet airliners also had NWB. The first jet with it must have been the Me262. Mainwheel brakes activated by pedals and the nose by a squeezy grip (like a bike) on the control column.

Spooky 2 23rd Feb 2010 11:35

Galaxy Flyer, reread my post as I think that is what I said, or least meant. :}

The former -225ADV aircraft had the brakes. These wound up at Delta Airlines.

galaxy flyer 23rd Feb 2010 13:45

Spooky 2

Sorry 'bout that--I didn't think the -225ADV ever had them installed, only the -100 and -200. Learned something.

GF

virginpaul 23rd Feb 2010 13:56

727 NLG Brakes
 
I worked for Iberia in the very late '80's and they had the 727-200 with some equipment for the Nose Gear Brake system installed (boosters and some pipework in place in the NWW) but not used (no brakes fitted). The nose wheels still had the drive lugs for the brake rotors at that time.
Paul

EAL shuttle 19th Aug 2023 15:05

B727 NWL
 

Originally Posted by hetfield (Post 5523723)
Yeah NLG were an option. In our fleet we used to have more than ten aircraft equipped with NLG but I never heared of a replacement because they simply were not used. It's long ago but AFAIK the pedals had to be deployed to their maximum to activate them. (was there also a speed limit for them, don't remember?) There is very good reason for that. Everybody who has ever ridden a motorbike knows the forces up front during braking. So on the 727 nose gear strut the torque had to be limited not to overstress the strut. An option to get some better numbers on the performance charts like the option of rockets for engine failure on high elevation airports like La Paz.

This is a very good observation. I was blessed with the pleasure of flying the B727 for 7k hrs. NWB were expensive to maintain. Therefore, some companies de activated them on airplanes so equipped. I recall flying to Wilkes Berry Scranton in the winter, NWB were mandatory for dispatch.
Jose

CV880 20th Aug 2023 23:09

Re post #4, yes the Convair 880/990 had nose wheel brakes. To the best of my recollection they only operated when the brake pedals were fully depressed (desperation mode) and were either full on (relying on the antiskid to prevent lock up) or off. Nosewheel steering inputs beyond a certain point would also release the nw brakes if applied. The nosewheels were on a common axle with a single antiskid transducer and antiskid valve. I think they might have looked after the spin down braking on retraction but it was a very long time ago. I believe there was an incident, before my time on 880's, where one had full nosewheel braking applied on touchdown due to a malfunction and came to a rapid stop with square nose wheels and damage to the bottom end of the nose leg. I cannot recall ever replacing nosewheel brakes due to wear.

Obama57 23rd Aug 2023 23:54

I think EAL had 3 -17’s used for South America - La Paz that had oversized MLG wheels, nose brakes, and “black power” ( higher EPR with an engine failure on takeoff.) I started in ‘79 and the nose brakes were all deactivated by then.

CVividasku 24th Aug 2023 00:34

I don't recall if anyone said it, but nosewheel brakes should be helpful at every flight to reduce wheel vibration when gear is retracted, as is done on the main gear wheels.
I wish we had that type of brakes on the A320. They would only require a very small brake system, and would not impact navigability in case of failure/absence.

tdracer 24th Aug 2023 02:27


Originally Posted by CVividasku (Post 11490287)
I don't recall if anyone said it, but nosewheel brakes should be helpful at every flight to reduce wheel vibration when gear is retracted, as is done on the main gear wheels.
I wish we had that type of brakes on the A320. They would only require a very small brake system, and would not impact navigability in case of failure/absence.

The problem with making a nosewheel braking system basic is then it has to be part of the MEL. While you can dispatch with the system inop via the MEL - there must be a time limit associated with the MEL dispatch - so you'll eventually have to spend the money to fix it. So the operators would need to pay the cost of adding the feature, then spend more money keeping it working to avoid having aircraft grounded.
Operators don't like that - especially when a cheap, simple snubber in the nose gear wheel well gets the job done (if perhaps not very gracefully).


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