Use of rudder in jet aircraft
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Use of rudder in jet aircraft
Obviously one uses the rudder during take-off and landing, especially in cross-wind conditions, but whilst hand-flying a big jet do you use rudder to co-ordinate turns or does the yaw damper take care of it all?
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ru - basic answer - no, in my experience, and the yaw damper is essentially there to counter turbulence yaw. Modern aircraft have control surfaces which counter the 'adverse yaw' of which I assume you are thinking?
Only half a speed-brake
On a 737 -4/500 I have humble experience with, the yaw damper remains engaged from pre-flight prep until engine shut-down. Amongst heap of its functions, the book says it provides turn co-ordination. So I've been taught not to touch the rudder at all except to kick off drift before touch-down (and supposingly, some would-be-american-style trainers teach not to do it at all) or, keep the aircraft aligned with runway during ground rolls. And this works perfectly for normal ops. When in need of rudder trim shortly after take off, I endaveour to put a little touch on the pedals rather than letting go one hand off the controls a blindly search for the knob (our installations have three or so positions on the central pedestal, it ges funny sometimes). Simple as that.
Fly safe,
FD.
Fly safe,
FD.
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Rudder
In the B737 I used the rudder to straighten the AC with the
centerline and during single engine. In the B777 you use it just
for directional control to the centerline. When the TAC is on then
you do not need to compensate for assymetric thrust by yourself
the rudder got "pushed" for you by the magic TAC.
NG
centerline and during single engine. In the B777 you use it just
for directional control to the centerline. When the TAC is on then
you do not need to compensate for assymetric thrust by yourself
the rudder got "pushed" for you by the magic TAC.
NG
Only half a speed-brake
Oh, I wish my young mind retained more information then it does. Just to strengten our conclusions, the 737 FC Training Manual has a training section on steep turns (being American, they speak of banks above 30°) of 45°. No mention for rudder at all.
Fly safe,
FD.
Fly safe,
FD.
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Newer designs do not require much (if any) rudder in normal flight.
Older types (B707) did indeed require some rudder in turns to assure co-ordination.
Now listen up, this is rather important.
Large rudder inputs at higher speeds leads to rather BIG problems, as some 'know it all' American operators have found out in the recent past.
And yes, just to be completely clear, am refering to AMERICAN AIRLINES.
Sadly, many there NOW, don't have a clue.
Lessons learned from the past seem to be totally forgotton at the AA doorstep. Why should we be surprised?
The lawyers will find out the dirty linen...and it ain't gonna be pretty, IMO.
Older types (B707) did indeed require some rudder in turns to assure co-ordination.
Now listen up, this is rather important.
Large rudder inputs at higher speeds leads to rather BIG problems, as some 'know it all' American operators have found out in the recent past.
And yes, just to be completely clear, am refering to AMERICAN AIRLINES.
Sadly, many there NOW, don't have a clue.
Lessons learned from the past seem to be totally forgotton at the AA doorstep. Why should we be surprised?
The lawyers will find out the dirty linen...and it ain't gonna be pretty, IMO.
There are some good answers here. It is most important to understand how the yaw dampers work on your own aircraft, different types work differently.
I once had a large dutch roll develop at FL280 in a comet. One yaw damper had failed and the other one had stuck solid, the second was therefore putting in opposite inputs. Had to switch of both yaw dampers and use rudder to recover. But it took a while to work out as the standard dutch roll recovery made things worse. Later found out from some old timers that this was a common fault in Comets and older 707s, seems the corporate knowledge had been lost.
I suggest you read JP Davies Handling the Big Jets which will give you a good basic understanding on which to build your knowledge. Then apply it to your own type.
I agree that in most cases you should never need to put in large inputs in modern big jets.
MM
I once had a large dutch roll develop at FL280 in a comet. One yaw damper had failed and the other one had stuck solid, the second was therefore putting in opposite inputs. Had to switch of both yaw dampers and use rudder to recover. But it took a while to work out as the standard dutch roll recovery made things worse. Later found out from some old timers that this was a common fault in Comets and older 707s, seems the corporate knowledge had been lost.
I suggest you read JP Davies Handling the Big Jets which will give you a good basic understanding on which to build your knowledge. Then apply it to your own type.
I agree that in most cases you should never need to put in large inputs in modern big jets.
MM
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The yaw damper is installed to improve stability (read: damp occilations) and flight control laws in case of certain malfunctions.
Basically; any yaw that is NOT caused by pilot or auto-pilot input to the rudder will be acted upon by the yaw damping system.
On the B 777, at low speeds there is a cross-tie between the ailerons and rudder on the B 707 this didn't exist.
Basically; any yaw that is NOT caused by pilot or auto-pilot input to the rudder will be acted upon by the yaw damping system.
On the B 777, at low speeds there is a cross-tie between the ailerons and rudder on the B 707 this didn't exist.
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Of course there was no specific cross tie between ailerons and rudder in the B707, Cap56, as it was a bell crank/control cable/push rod manually controlled aircraft, with no hydraulic boost on any primary control, except the rudder.
No such thing as 'control laws' either on this early Boeing type.
Suppose you could consider the Q feel for the rudder to be a 'control law' but that would certainly be a stretch.
No such thing as 'control laws' either on this early Boeing type.
Suppose you could consider the Q feel for the rudder to be a 'control law' but that would certainly be a stretch.
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