A320ajm From United Kingdom, joined May 2006, 504 posts, RR: 0 Posted (1 year 4 weeks 1 day 22 hours ago) and read 2738 times:
Hey,
On the flight sim joystick I have, the rudder is controlled by twisting the joystick on its own axis in a kind of third dimension i.e. not left right, or forward back.) Just a question regarding if any aircraft have this system in place and if not, why is it a bad idea? Is it simply more coordination to control a plane in 3 dimensions with 1 stick? I can imagine it being easy to implement on a fly by wire aircraft. I'm don't have much knowledge in the engineering/technical side of aviation so apologies if this is stupid question.
Thanks,
A320ajm
If the British Empire and its Commonwealth last for a thousand years, men will still say, 'This was their finest hour.'
Because you have rudder pedals for that, and those are easier to manipulate than a z-axis on a joystick. It could certainly be done, but there isn't a whole lot of need for that sort of thing.
-Mir
7 billion, one nation, imagination...it's a beautiful day
A320ajm From United Kingdom, joined May 2006, 504 posts, RR: 0 Reply 3, posted (1 year 4 weeks 1 day 20 hours ago) and read 2665 times:
Thanks for your replies
My thoughts were based around how everything is getting smaller, more compact, making one item have multiple tasks. Wondered if pedals one day would be a thing of the past!
Regards,
A320ajm
If the British Empire and its Commonwealth last for a thousand years, men will still say, 'This was their finest hour.'
tdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80 Reply 4, posted (1 year 4 weeks 1 day 19 hours ago) and read 2613 times:
Quoting A320ajm (Thread starter): Just a question regarding if any aircraft have this system in place and if not, why is it a bad idea?
I don't know of any current aircraft with that feature; the single biggest argument against it, now, is pilot training. Although the yoke-vs-sidestick thing will never die, every pilot knows that pedals are for rudder and brakes. Trying to break that habit would require a huge retraining bill with no really obvious payoff.
It's like asking why a car's gas pedal is on the left and not the right...no particular reason it has to be that way a priori, but try changing it now...
Quoting A320ajm (Thread starter): Is it simply more coordination to control a plane in 3 dimensions with 1 stick?
Yes, although if you spent as much time on the rudder as you do on the other 2 axis it might make sense but, of the three, the rudder is used the least by far.
Quoting A320ajm (Thread starter): I can imagine it being easy to implement on a fly by wire aircraft.
Very. But the way they deal with it is to just build the rudder into the lateral/directional control law so the flight crew doesn't need to manually put in rudder at all except in some very specific circumstances.
Quoting A320ajm (Reply 3): Wondered if pedals one day would be a thing of the past!
Still need to work the brakes in there somewhere. If you've got "free" pedals you might as well use them.
CM From , joined Dec 1969, posts, RR: Reply 5, posted (1 year 4 weeks 1 day 14 hours ago) and read 2526 times:
Quoting A320ajm (Reply 3): Wondered if pedals one day would be a thing of the past!
Not likely.
The rudder is unique among flight controls in a couple ways:
1. It has very large control authority (particularly in short body length twins).
2. The fin is an asymmetric planar surface (it does not pass completely through the fuselage and have a symmetric fin underneath), meaning the rudder load is not reacted into the fuselage by a structural box in a symmetrical manner (compare to the horizontal stabilizer).
Because of these two things, the rudder has the ability to easily exceed the design load of the structure during a control reversal.
I haven't used a z-axis joystick, but I imagine it would be very easy to slap the rudder left and right with my wrist. In an aircraft with rudder pedals, it takes very deliberate action and effort by a pilot to rapidly reverse the rudder. In a PC sim, that's OK. In a real airplane, it will snap off the tail. You can read about an event where this happened by reading about American Airlines Flight 587.
horstroad From Germany, joined Apr 2010, 189 posts, RR: 0 Reply 7, posted (1 year 4 weeks 1 day 13 hours ago) and read 2506 times:
Quoting tdscanuck (Reply 4): It's like asking why a car's gas pedal is on the left and not the right
isn´t the gas pedal on the right?
Quoting CM (Reply 5): but I imagine it would be very easy to slap the rudder left and right with my wrist [...] it will snap off the tail
this could be easily inhibited as you are not directly addressing the surfaces...
i think one problem is that you could move the rudder accidentally by moving the side-stick sideways or other way round.
and it´s quite a complex thing to control all three dimensions with only one hand. just think about decrabbing a plane in a crosswind approach with some gusts. i think it´s not bad to "outsource" some work to the feet
MD11Engineer From Germany, joined Oct 2003, 13368 posts, RR: 64 Reply 8, posted (1 year 4 weeks 1 day 12 hours ago) and read 2477 times:
Quoting tdscanuck (Reply 4): Quoting A320ajm (Thread starter):
Just a question regarding if any aircraft have this system in place and if not, why is it a bad idea?
I don't know of any current aircraft with that feature; the single biggest argument against it, now, is pilot training. Although the yoke-vs-sidestick thing will never die, every pilot knows that pedals are for rudder and brakes. Trying to break that habit would require a huge retraining bill with no really obvious payoff.
It's like asking why a car's gas pedal is on the left and not the right...no particular reason it has to be that way a priori, but try changing it now...
Early aircraft had the weirdest flight control configurations (e.g. two control sticks on the Wright Flyers, one for pitch and roll and the other one for yaw). Standartisation came somewhere around 1910 (before WW1).
Similarly every car manufacturer had different ideas on where to place the controls, but again, before 1910, there was some standartisation to the configuration you´ll find today (at about the same time a driving licences were introduced).
Hey - I resent that - and I spend about 50% of my time in places where I have to drive on the wrong side of the road (I'll let you decide for yourself which is correct, but I'm going to suggest it's called the 'right' side of the road for a reason, even though it might infer that I am sinistrel since my left hand is dominant.
There are also systems to deal with pesky rudder pedals in aircraft (unless you have an Ercoupe of course).
FWIW, I the first time I tried a Z-Axis control instead of pedals on a flight sim, it seemed incredibly intuitive to me...no more difficult than switching from my own truck at the airport parking lot into a rental car a few hours later.
If it did get put into a fly by wire system 'for real' I imagine it would be no different than the yoke vs joystick vs sidestick threads - which seem to indicate that people figure it out quickly (all my personal flying has been yoke with very minor joystick time).
I could also see an advantage in gusty x-wind landings...no worrying about whether the brake is on holding the slip to touchdown.
akiss20 From United States of America, joined Sep 2007, 534 posts, RR: 0 Reply 13, posted (1 year 4 weeks 1 day 2 hours ago) and read 2192 times:
One thing to note is that it might be a bit more difficult to provide independent rudder and aileron inputs with this system. I could see a pilot accidentally adding a bit of aileron to his rudder command depending on how damped the stick and twist is. There are times where you want to decouple the two actions (for example, on an ILS I often just use a little bit of rudder to head off any deviations that begin to form. Aileron is too big a command input for the small correction I need). I'm not ME rated, so this may be way off course, but I could also see in the case of an engine failure when you are correcting with a lot of rudder it being more difficult to keep the right amount of rudder in while doing things with the stick.
Just a thought.
Change will not come if we wait for some other person or some other time. We are the ones we've been waiting for. We are
Chimborazo From United Kingdom, joined Sep 2011, 64 posts, RR: 0 Reply 14, posted (1 year 4 weeks 1 day ago) and read 2169 times:
Quoting BE77 (Reply 12): I'll let you decide for yourself which is correct, but I'm going to suggest it's called the 'right' side of the road for a reason, even though it might infer that I am sinistrel since my left hand is dominant.
My understanding of the driving on left/right argument is thus:
Long before motor transport when it was either horse or foot, people would stay to the left as they passed each other as the vast majority are right-handed. They're then on the "correct" side of you if you have to draw your sword to defend yourself (or attack I suppose). The habit continued in the motor age.
Americans began driving on the right simply because of happenstance: the early horse-drawn stage coaches simply had the running board on the right. Which naturally led to the stage stopping on the right side of the road and the rest is history...
That's how I heard it anyway. In which case the right isn't right, the left is right
Anyway, it makes it so much more interesting driving when I go abroad. Especially when I open the driver's door to find someone has stolen the steering wheel: nonchalantly adjust something on the passanger seat and mosey on round to the other side trying to look cool...
horstroad From Germany, joined Apr 2010, 189 posts, RR: 0 Reply 15, posted (1 year 4 weeks 17 hours ago) and read 2015 times:
Quoting Chimborazo (Reply 14): Americans began driving on the right simply because of happenstance
lol it´s not always the americans^^ as far as i know the french (robespierre/napoleon) adopted the right side traveling... the british on their island just didn´t notice and brought it to their colonies
Starlionblue From Hong Kong, joined Feb 2004, 15904 posts, RR: 66 Reply 16, posted (1 year 4 weeks 13 hours ago) and read 1974 times:
Quoting BE77 (Reply 12): FWIW, I the first time I tried a Z-Axis control instead of pedals on a flight sim, it seemed incredibly intuitive to me...no more difficult than switching from my own truck at the airport parking lot into a rental car a few hours later.
If it did get put into a fly by wire system 'for real' I imagine it would be no different than the yoke vs joystick vs sidestick threads - which seem to indicate that people figure it out quickly (all my personal flying has been yoke with very minor joystick time).
I could also see an advantage in gusty x-wind landings...no worrying about whether the brake is on holding the slip to touchdown.
The rudder in an airliner is mainly used in situations like crosswind landings, engine outs. As akiss20 notes, you really don't want to make things more complicated by risking adding aileron to rudder or vice versa.
More importantly, pedals ain't broke. Z-axis joysticks don't have any inherent advantage (except maybe weight) so there's little point using them unless the pilot doesn't have legs.
Regarding driving on the left or right, I don't think it really matters as long as everyone in the country agrees to drive on the same side.
Quoting Chimborazo (Reply 14): Anyway, it makes it so much more interesting driving when I go abroad. Especially when I open the driver's door to find someone has stolen the steering wheel: nonchalantly adjust something on the passanger seat and mosey on round to the other side trying to look cool...
Almost 5 years in HK and I STILL do that from time to time!
"There are no stupid questions, but there are a lot of inquisitive idiots." - from Citadel by John Ringo
So not only do you North Americans drive on the wrong side of the road, your gas and brake pedals are on the wrong side too.
Nah just the Canadians
If you can trust Wikipedia, 4 Canadian provinces (Nova Scotia, New Brunswick, Prince Edward Island, British Columbia) drove on the left until the early 1920s when they switched to the right like the rest of Canada and of course the U.S. Newfoundland, which didn't become part of Canada until 1949, switched from left to right in 1947.
787atPAE From United States of America, joined Oct 2006, 143 posts, RR: 4 Reply 18, posted (1 year 3 weeks 4 days 20 hours ago) and read 1413 times:
One big negative I've heard about yaw/directional control via sticks (passive OR active) would be the inadvertent cross-coupling between the lateral and directional axes by the pilot. I doubt there's a way to strictly keep a roll or way command without commanding the other axis. For example, a roll command would also invite a yaw command with sticks.
Sponsor Message: 
From United Kingdom, joined May 2006, 504 posts, 
From United States of America, joined Jan 2004, 19813 posts, 
From Germany, joined Oct 2003, 13368 posts, 
From Canada, joined Jan 2006, 12709 posts, 
From Australia, joined Mar 2006, 2589 posts, 
From Hong Kong, joined Feb 2004, 15904 posts, 
From Switzerland, joined Oct 2006, 21679 posts, 
Sponsor Message: 
Printer friendly format
