The fine art of....Taxying?
Thread Starter
Join Date: Jun 2006
Location: Essex
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
The fine art of....Taxying?
I have recently taken up flight training at Stapleford in Essex, and what can I say? Fantastic experience and looking forward to progressing!
Anyway, at this early stage in my training, I'm having some difficulty with taxying the aircraft (Cessna 152) and I do exacly as my instructor tells me to do by turning ailerons into winds, keeping the propeller clear of the rough grassy ground, and generally try not to use excessive power when moving near people.
But through all this, I do understand that there is a slight delay on pushing the rudders and the final movement of the nose of the plane, but I still can't keep the aircraft straight! Is there any technique(s) that helps keep this aircraft on the yellow line? Or is it simply that is comes with practice (as my instructor insisted whilst gripping very tightly to the dashboard...)?
Many thanks in advance to your help.
Anyway, at this early stage in my training, I'm having some difficulty with taxying the aircraft (Cessna 152) and I do exacly as my instructor tells me to do by turning ailerons into winds, keeping the propeller clear of the rough grassy ground, and generally try not to use excessive power when moving near people.
But through all this, I do understand that there is a slight delay on pushing the rudders and the final movement of the nose of the plane, but I still can't keep the aircraft straight! Is there any technique(s) that helps keep this aircraft on the yellow line? Or is it simply that is comes with practice (as my instructor insisted whilst gripping very tightly to the dashboard...)?
Many thanks in advance to your help.
Join Date: Dec 2003
Location: Massachusetts Bay Colony
Age: 57
Posts: 476
Likes: 0
Received 0 Likes
on
0 Posts
PPL-T,
Welcome to the club! It's a great road you've started down and a whole world of new experiences await!
Straight taxying is a bit like that elusive golf shot that actually goes where you wanted it to go. It happens, but not all that often!
Actually, taxying, like anything, comes with practice and you WILL get the hang of it. Every airplane is different, just like every car is different, and they all take a little bit of getting used to. It'll happen. Just remember that, more than keeping it on the yellow line (when there is one), the important thing to remember is not to hit anything. Everything after that is really just gravy.
Pitts2112
Welcome to the club! It's a great road you've started down and a whole world of new experiences await!
Straight taxying is a bit like that elusive golf shot that actually goes where you wanted it to go. It happens, but not all that often!
Actually, taxying, like anything, comes with practice and you WILL get the hang of it. Every airplane is different, just like every car is different, and they all take a little bit of getting used to. It'll happen. Just remember that, more than keeping it on the yellow line (when there is one), the important thing to remember is not to hit anything. Everything after that is really just gravy.
Pitts2112
Join Date: Jun 2003
Location: EuroGA.org
Posts: 13,787
Likes: 0
Received 0 Likes
on
0 Posts
It will come. A C152 which was (possibly) made before you were born isn't going to have the steering precision of a car. The whole thing up front is going to be well sloppy; probably worse than your lawnmower. And wind is going to shift it about quite a bit too.
Join Date: Feb 2005
Location: England
Posts: 551
Likes: 0
Received 0 Likes
on
0 Posts
Thread Starter
Join Date: Jun 2006
Location: Essex
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
Thank you all very much for your replies to my query, and I will see if I can put these theories into practice! Fingers crossed I won't hit anything!
(Soay, thanks I'll try that method).
Once again, thanks for your help.
P.S Thanks Pitts2112 for the Warm welcome!
(Soay, thanks I'll try that method).
Once again, thanks for your help.
P.S Thanks Pitts2112 for the Warm welcome!
Join Date: Jun 2003
Location: EuroGA.org
Posts: 13,787
Likes: 0
Received 0 Likes
on
0 Posts
Taxiing is the most dangerous part of flying, IMHO 
Potholes, wingtip damage, more potholes.
1 pothole = 15,000 quid damage or so if the prop as much as touches anything other than air.
Potholes, wingtip damage, more potholes.
1 pothole = 15,000 quid damage or so if the prop as much as touches anything other than air.
Join Date: Oct 2005
Location: England
Posts: 518
Likes: 0
Received 0 Likes
on
0 Posts
as mentioned, its the same with any vehicle, if you look too close to where you are, you will steer towards it, look where you want to be, relax, and its like magic, it just goes there !
Join Date: Apr 2003
Location: Bordeaux, France
Posts: 581
Likes: 0
Received 0 Likes
on
0 Posts
Taxiing is the most dangerous part of flying, IMHO. Potholes, wingtip damage, more potholes.
Thread Starter
Join Date: Jun 2006
Location: Essex
Posts: 11
Likes: 0
Received 0 Likes
on
0 Posts
10540
At last TAXIING....not TAXYING!
UV
At last TAXIING....not TAXYING!
UV
Apologies for any confusion!
I'm glad to find I'm not the only "Loony Toon" who finds taxiing tricky!
Heres another question. Is it a good idea to push the rudder pedals one way quickly and pushing quickly the other to keep the nose straight or could that cause problems with the nose wheel or damage it? I've noticed that the rudder pedals take a while to centre again after being pushed one way. Would returning the wheel to the centre again by pressure on the opposite rudder pedal help keep the plane straight by forcefully moving the pedals back to neutral?
Thanks for your help in advance.
Join Date: Apr 2005
Location: Australia
Posts: 1,414
Likes: 0
Received 0 Likes
on
0 Posts
as my instructor tells me to do by turning ailerons into winds
Same with crosswind take offs where some instructors teach lots of into wind aileron in five knots of crosswind. Its a myth.
The rudder pedals should centralise themselves after an input while you are taxiing. If they stay where they are instead of centralising I suggest the instructor should write this in the aircraft maintenance log as a definate defect.
I suspect that your main problem *may* be that you are chasing the aeroplane.
Slow your pedal inputs down, use small slow corrections, and ease - not force, the aeroplane to the centreline.
Actually, this is the best way to get an aeroplane to any condition you want - taxiway centreline, heading, height, etc. etc....
If you wish, I can explain the theory behind this, but try it first and see if it helps.
G
Slow your pedal inputs down, use small slow corrections, and ease - not force, the aeroplane to the centreline.
Actually, this is the best way to get an aeroplane to any condition you want - taxiway centreline, heading, height, etc. etc....
If you wish, I can explain the theory behind this, but try it first and see if it helps.
G
Join Date: Jan 2001
Location: In my own little world
Posts: 776
Likes: 0
Received 0 Likes
on
0 Posts
I always found that by letting go of the yoke, it helped me taxi. Initially I was trying to steer like a car 
then a split second later I would realise what I had done when we were not turning, and get on the pedals. Eventually I just gave up holding the yoke when taxiing (unless in strong wind or on grass) and was fine after that.
I also use the odd bit of differential braking here and there to help me when taxiing too - normally in tight spaces and when doing 180 turns etc.
You will get the hang of it eventually.
BTW, what are the instructors like at Stapleford. I just signed up with them to hour build, but got to do my check flight. I was ill last week so couldn't do it. Hoping to do it on Thursday if I'm 100% again.
then a split second later I would realise what I had done when we were not turning, and get on the pedals. Eventually I just gave up holding the yoke when taxiing (unless in strong wind or on grass) and was fine after that.I also use the odd bit of differential braking here and there to help me when taxiing too - normally in tight spaces and when doing 180 turns etc.
You will get the hang of it eventually.
BTW, what are the instructors like at Stapleford. I just signed up with them to hour build, but got to do my check flight. I was ill last week so couldn't do it. Hoping to do it on Thursday if I'm 100% again.
Join Date: May 2005
Location: Abroad
Posts: 1,172
Likes: 0
Received 0 Likes
on
0 Posts
Fair enough.
Any control system has a natural frequency - a sort of sine wave behaviour at which it responds to sudden inputs. You can see this in a car or bike - make a sudden (small !!!!!) input to the steering wheel, and you'll see it make a few small swerves back and forth before re-establishing a straight track, or in flight do the same on the stick or rudder in any of the three axes, and you'll see something similar. Whilst it's not likely to help your instructors blood pressure, assuming that your aeroplane has self centring steering (virtually all do) the same will work with the ground steering.
The frequency of that sine wave response, in the vast majority of cases, is very fast - around 1Hz would be normal for a light aeroplane's nosewheel steering, or pitch control, maybe 0.5 Hz in yaw and roll.
Because the control circuit uses that frequency, you have problems with any input that is at the same frequency or a lot faster. So (DO NOT DO THIS - test pilots do this sort of thing, because they've trained for it, it is possible to pull the aeroplane apart if you do it wrong) if you waggle the stick for-and-aft very fast in flight, the aeroplane does virtually nothing. If you slow down to the frequency of the control system (say 1 Hz, it'll be about that) then the aeroplane operates in anti-phase to the stick input. So, as you push the stick forward the aircraft pitches nose-up, and as you pull the stick back the aircraft pitches nose-down - it's also possible to amplify the response very quickly and possibly pull the wings off (I'd certainly not do it in a T67 for example, which has a very poorly damped short period pitch mode). This is arguably confusing and unhelpful behaviour, and not to be encouraged. If you move the stick much slower than this (which is what we all normally do) then the input is sufficiently slower than the aircraft response that you see nothing odd, and the aeroplane simply does what it's told.
Now, coming back to the issue of the nosewheel steering. That steering circuit will also, as I said, have a frequency around the 1Hz mark. If you make rapid inputs, then you are getting around this frequency, and as a result the aeroplane does not steer in the direction that you expected, because you are putting inputs in at the wrong point in the cycle. The result will be an aeroplane that swerves all over the place and appears to be uncontrollable. The technical term for this is a "PIO" or "Pilot Induced Oscillation", and it can be prevented by gradual control inputs, or if it is really all getting to much, just clamping the offending control in the middle until the aeroplane sorts itself out, then trying again.
I hope that was reasonably clear - it's much easier with diagrams!
G
Any control system has a natural frequency - a sort of sine wave behaviour at which it responds to sudden inputs. You can see this in a car or bike - make a sudden (small !!!!!) input to the steering wheel, and you'll see it make a few small swerves back and forth before re-establishing a straight track, or in flight do the same on the stick or rudder in any of the three axes, and you'll see something similar. Whilst it's not likely to help your instructors blood pressure, assuming that your aeroplane has self centring steering (virtually all do) the same will work with the ground steering.
The frequency of that sine wave response, in the vast majority of cases, is very fast - around 1Hz would be normal for a light aeroplane's nosewheel steering, or pitch control, maybe 0.5 Hz in yaw and roll.
Because the control circuit uses that frequency, you have problems with any input that is at the same frequency or a lot faster. So (DO NOT DO THIS - test pilots do this sort of thing, because they've trained for it, it is possible to pull the aeroplane apart if you do it wrong) if you waggle the stick for-and-aft very fast in flight, the aeroplane does virtually nothing. If you slow down to the frequency of the control system (say 1 Hz, it'll be about that) then the aeroplane operates in anti-phase to the stick input. So, as you push the stick forward the aircraft pitches nose-up, and as you pull the stick back the aircraft pitches nose-down - it's also possible to amplify the response very quickly and possibly pull the wings off (I'd certainly not do it in a T67 for example, which has a very poorly damped short period pitch mode). This is arguably confusing and unhelpful behaviour, and not to be encouraged. If you move the stick much slower than this (which is what we all normally do) then the input is sufficiently slower than the aircraft response that you see nothing odd, and the aeroplane simply does what it's told.
Now, coming back to the issue of the nosewheel steering. That steering circuit will also, as I said, have a frequency around the 1Hz mark. If you make rapid inputs, then you are getting around this frequency, and as a result the aeroplane does not steer in the direction that you expected, because you are putting inputs in at the wrong point in the cycle. The result will be an aeroplane that swerves all over the place and appears to be uncontrollable. The technical term for this is a "PIO" or "Pilot Induced Oscillation", and it can be prevented by gradual control inputs, or if it is really all getting to much, just clamping the offending control in the middle until the aeroplane sorts itself out, then trying again.
I hope that was reasonably clear - it's much easier with diagrams!
G
Join Date: May 2005
Location: Abroad
Posts: 1,172
Likes: 0
Received 0 Likes
on
0 Posts
