A dumb question on differential brakes
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A dumb question on differential brakes
Dear all...
I am really sorry to ask such a question but I think only you can help.
I wonder whether the big birds like 737, 777 or A3XX have differential brakes or not? Do the pedals control all brakes simultaneously or only the respective side like general aviation aircraft?
Thank you very much.
Sumer Yamaner
I am really sorry to ask such a question but I think only you can help.
I wonder whether the big birds like 737, 777 or A3XX have differential brakes or not? Do the pedals control all brakes simultaneously or only the respective side like general aviation aircraft?
Thank you very much.
Sumer Yamaner
The brake pedals only apply brakes on their respective side. And yes to some extent you can use differential braking on the big birds, such as when you making a 180° turn on narrow runways. Probably puts a bit of strain on the landing gear though.
Useless anecdote that's probably not reliable - If you're right-handed then you tend to push a little harder on the left brake pedal and vice-versa.
Had a couple of good Flight Engineers tell me (correctly) that I was right-handed after landing by looking at the brake temps.
Had a couple of good Flight Engineers tell me (correctly) that I was right-handed after landing by looking at the brake temps.
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If you're right-handed then you tend to push a little harder on the left brake pedal and vice-versa.
The reason? simple really.
Which foot operates the accelerator and brake in your car?
Which foot operates the clutch?
Which of the two requires a sensitive touch and many different pressures to achieve a smooth drive - and which is operated almost like an on/off switch?
Thus most pilots (or at least those who drive manual cars!) tend to unintentionally brake harder on the left side.
Don't believe me?
Try this.
Get in your car.
Find a nice straight road with no traffic about.
Accelerate to approx 60 kph (in whatever gear is required/ comfortable).
Lift your right foot off the accelerator.
Place your LEFT foot over the brake pedal and brake normally.
Make sure you wear your seatbelt
Oh and don't believe everything the Flight Engineer tells you unless it's details of the cheapest place for breakfast downroute, the loudest bar or the raciest strip club
Try this.
Get in your car.
Find a nice straight road with no traffic about.
Accelerate to approx 60 kph (in whatever gear is required/ comfortable).
Lift your right foot off the accelerator.
Place your LEFT foot over the brake pedal and brake normally.
Make sure you wear your seatbelt
Get in your car.
Find a nice straight road with no traffic about.
Accelerate to approx 60 kph (in whatever gear is required/ comfortable).
Lift your right foot off the accelerator.
Place your LEFT foot over the brake pedal and brake normally.
Make sure you wear your seatbelt
But yes as I wrote above, it's not an entirely reliable anecdote.
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From what I can remember of my B747-200 course of many years ago....
The brake cables between the rudder pedals and the brake control valves are rigged at a different tensions.
One side is rigged at 120- 140 pounds cable tension and the other at 130-150 pounds cable tension. Forget which side is the highest, and using these tensions as a guide only. I am talking about this being the Captains side only, the First Officer would have his side rigged about the same.
This is to overcome the difference in pressure that people put on the brake pedals, being used to different forces when operating car brake and clutch pedals.
The brake cables between the rudder pedals and the brake control valves are rigged at a different tensions.
One side is rigged at 120- 140 pounds cable tension and the other at 130-150 pounds cable tension. Forget which side is the highest, and using these tensions as a guide only. I am talking about this being the Captains side only, the First Officer would have his side rigged about the same.
This is to overcome the difference in pressure that people put on the brake pedals, being used to different forces when operating car brake and clutch pedals.
Last edited by Runaround Valve; 3rd Oct 2009 at 05:38.
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since i leave the breaking to auto-brake and anti-skid i don't see why one side should be warmer than the other in relation to if i am L or R handed or my type of car.....
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18-Wheeler,
I remember an engineer telling a crewof a corporate plane that they were landing only from the left seat because the engineer saw that the right hand side MLG was more worn out that the LH side.
I know, nothing to do with the original thread but I just wanted to share my experience.
I remember an engineer telling a crewof a corporate plane that they were landing only from the left seat because the engineer saw that the right hand side MLG was more worn out that the LH side.
I know, nothing to do with the original thread but I just wanted to share my experience.
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On the 330, with auto-brakes used routinely, I usually found the downwind (leeward?) brakes were almost always warmer than the windward brakes. But then again maybe I usually took the leg with the crosswind from the right (in reference to being right handed).
I attributed this temperature differential to weather-cocking induced yaw being countered by the differential braking and the shielding of the wind to assist cooling on the leeward side, but it was just my own theory.
BD
I attributed this temperature differential to weather-cocking induced yaw being countered by the differential braking and the shielding of the wind to assist cooling on the leeward side, but it was just my own theory.
BD
on the L1011....they removed the brake temperature gauges.Join Date: Dec 2003
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Busserday
Same on the 744, downwind side will tend to have less lift earlier in the landing run so those brakes will absorb more energy, especially when the landing pilot allows the windward wing to lift after touchdown.
...must keep "flying" after touchdown in a strong crosswind.
Same on the 744, downwind side will tend to have less lift earlier in the landing run so those brakes will absorb more energy, especially when the landing pilot allows the windward wing to lift after touchdown.
...must keep "flying" after touchdown in a strong crosswind.
