Slipping and Skidding - Dumb Question.

[Sunfish]

I have had continual trouble understanding slipping and skidding and the dangers inherent since I started flying. I will remove this thread if requested. My problem was exacerbated by sailing for fifty years - which made me extremely tolerant of out of balance situations, experience with a Piper Tripacer with linked rudder and ailerons and some fairly perfunctory flight instruction apart from my natural state of stupidity.

I get the idea of coordinated turns, especially base to final, and always ensure that this happens. However I could never quite work out why and how this was an issue. I just accepted ‘’step on the ball”.

I think I have finally understood this in a backhanded way - it’s about keeping the center of lift, laterally, directly above/ below the centre of gravity and not to the outside of the turn (skidding) or to the inside (slipping). My logic, FWIW, is that skidding produces an effect where the “upper” outside wing is producing more lift than the lower wing because the airflow is not parallel with the longitudinal access (too much rudder). This has the effect of increasing bank because the lateral displacement increases the load on the lower wing. The unconscious response is to try and raise the lower wing with aileron - increased drag, increased AoA and kablooey! You need to keep the centre of lift over the Cg and the tool for that is rudder. Does this explanation make sense to anyone?


In dinghy sailing downwind parlance this is analogous to “keeping the boat under the spinnaker” as opposed to trying to force the sail to stay over the boat. The first method works, the latter ends in disaster akin to a stall and spin, though not with the same consequences.

[Lead Balloon]

Hopefully the experts who chimed in on the Essendon King Air tragedy will add their wisdom shortly.

[machtuk]

The word Skidding sounds dangerous and is especially in a car, same analogy with planes.
You Over shoot the Rwy C/L so you stand on the rudder that points the nose towards the Rwy thinking that will get me back inline quick but the now outer wing is travelling faster producing more lift and the inner wing is slowing down producing less lift, add In loading up the wing (puli g back on the stick) cause it feels like you are getting low and there is the receipt for a stall and a funeral not long after,

[Lambswool]

The Ag boys know all about this. Sometimes forgotten by some, but here is a good practical demonstration...

https://www.youtube.com/watch?v=2pGuoc11lxY

[djpil]

Here you are, Sunfish.
First from APS https://youtu.be/PMhoPJYCvXA
and take a look at the stuff on Jim’s website Dylan Aviation | School of Aerobatics and Airmanship » Blog Archive » Airmanship and the Base to Final Turn (http://www.dylanaviation.com/airmanship-and-the-base-to-final-turn/)

[alphacentauri]

Sunfish, a good emergency manoeuvres training course covers these things and lets you experience them both. The key is to learn what the aircraft will do if stalled in each one because its not the same. The videos are good at showing that.

If your instructor knows what they are talking about you should learn that its not the slip or skid that is the problem, its the load on the wing whilst in those manoeuvres that is the problem. Noting that both scenarios result in a loss of lift and a natural reaction is to load up the wing to maintain lift.

Do a good EMT course. Its worth it and makes you much more confident. If you can, do it in an aerobatic capable aircraft. I did mine in a Pitts, but i hear the Citabria is also quite good for it.

[cattletruck]

it’s about keeping the center of lift, laterally, directly above/ below the centre of gravity

I remember picking up an unofficial autobiography by Charles Kingsford Smith from the library of the aptly named Southern Cross University in Lismore, where a particular paragraph stuck in my young mind. Charles was once a passenger in a plane in some foreign country and noticing the engines were running flat out he availed himself to the cockpit where he saw the two pilots trying to get the plane over a mountain ridge. It was obvious to him that these pilots had no further options and if left to them were going to drive the plane into the mountains so he intervened and got them to lower the nose, build up airspeed and fly the wing over the mountains. In the book he further explained what he meant by fly the wing. This phrase (and the paragraph that followed) obviously struck a chord with me.

Once you "get" it (and it's not that hard, think of the exceptional Bob Hoover) then benign tasks like nicely balanced turns under all sorts of circumstances (steep, climbing, decending, tightening, turbulence, etc) are better understood and handled. In fact Alpha's advice on stalling in a skid or slip (with the right aircraft and safety precautions) is something I have never thought of doing to put the fly the wing to the test, and now has me intrigued.

To think, way before I picked up that book and was much greener, we thought doing cross-controls on finals at YMMB was normal. Thank heavens they banned that practice and got us to sharpen our skills from the downwind stage.

[aroa]

Theres some old saying ?...For every speed and rate of turn there is a correct angle of bank.
Not enough bank for the speed..outwards skid
Too much bank for the speed...inwards slip
With those big old slip n skid 2 needle instruments very easy to see whats going on.
Lower needle gives the rate of turn and the upper will move left or right as unbalanced...both labeled 'side slip'

[Roj approved]

Sorry Sunfish, but I am struggling to understand something.

You have over 8000 posts on this forum, exalting all things aviation, management ideology, business advice for all and sundry, constant attacks on QF, VA, CASA, ATSB, and the degradation of the profession to name a few.

I have had continual trouble understanding slipping and skidding and the dangers inherent since I started flying.

Now, at post number 8135, you ask a question, which by all means is a fair question, and one that needs to be answered correctly for your continued safe progress in aviation, but may put into question any credibility you may have as a "Professional" in the Aviation industry.

You stupids still don't understand.

In the past 8000+ posts you have attacked other users mercilessly over their understanding of the finer points of all things Aviation, but maybe, you should have spent this time getting to grips with one of the fundamentals of actual Aviation, balanced flight.

If you have spent 50 years sailing, then you should have ¾ of the practical side of flying in your toolbox of skill. Balanced turns, Angle of Attack, Centre of Gravity, Centre of Pressure, Height for Speed, plus some experience in the area of decision making and forward thinking.

Please, spend sometime using your considerable "experience" in your profession to set yourself up with a very solid foundation of Flying knowledge, so you can build your skills and better yourself as a pilot, and give up on the personal attacks on anyone that disagrees with you, it's getting tiresome.

Remember, Aviation is not inherently dangerous, but to a greater degree than the sea, it is terribly unforgiving of any carelessness, incapacity or neglect.

[desert goat]

Sunfish

I would suggest joining a gliding club. After a few flights with a yaw string taped right in front of your face, all will become clear.

[Bodie1]

¾

How did you do that Grasshoppaaaaaahhhh?

[Roj approved]

How did you do that Grasshoppaaaaaahhhh?

It’s some keyboard setting that I can’t find now😩

[Bodie1]

Bloody hell, get my expectations up.............

[john_tullamarine]

How did you do that Grasshoppaaaaaahhhh?

For those who use the MS platforms, there is a very useful little program, character map - Windows\System32\charmap.exe in Win 10 and similar locations in previous versions. Great little utility to get easy access to all the ASCII and non-ASCII characters, including such as ¼, ½, ¾.

While charmap is easy peasy to use, you can also do it the old style way with direct entry via ALT codes. So, for instance, ¾ can be entered directly by holding the ALT key down while typing 0190 on the numeric keypad. There are various spots you can get the codes required but the easiest is in charmap. If you know the codes for the (generally few) non-keyboard characters you might use, then you just enter them as for normal typing via ALT codes.

No doubt the Macs and so forth have similar capabilities.

First thing I do with any new computer is find charmap and put a link to it on the desktop. One of my very frequently used gadgets in the toolbox ....

[machtuk]

How did you do that Grasshoppaaaaaahhhh?

For those who use the MS platforms, there is a very useful little program, character map - Windows\System32\charmap.exe in Win 10 and similar locations in previous versions. Great little utility to get easy access to all the ASCII and non-ASCII characters, including such as ¼, ½, ¾.

While charmap is easy peasy to use, you can also do it the old style way with direct entry via ALT codes. So, for instance, ¾ can be entered directly by holding the ALT key down while typing 0190 on the numeric keypad. There are various spots you can get the codes required but the easiest is in charmap. If you know the codes for the (generally few) non-keyboard characters you might use, then you just enter them as for normal typing via ALT codes.

No doubt the Macs and so forth have similar capabilities.

First thing I do with any new computer is find charmap and put a link to it on the desktop. One of my very frequently used gadgets in the toolbox ....


gee JT I got a headache now after reading that! What ever happened to bark and charcoal?

[Bodie1]

gee JT I got a headache now after reading that! What ever happened to bark and charcoal?

Same here, my eyes start to glaze even though it's something I'm interested in.

Thanks JT.

[Roj approved]

Bloody hell, get my expectations up.............

On iPad, SETTINGS-> GENERAL-> KEYBOARDS -> TEXT REPLACEMENT then it is in the list down the bottom

[Sunfish]

Roj approved, since when have I ever held myself out to be an expert on aviation???? I am a simple bug smasher smasher trying to better understand the art of flying and I have never said otherwise. Each flight for me is a learning experience.

On other matters I have some experience.

However if you think four bars on your epaulet makes you an expert in everything outside the cockpit, well........

On second thoughts, who the &^%$ are you to question anyone?

[john_tullamarine]

What ever happened to bark and charcoal?

I'm with you in that Luddite philosophy ... unfortunately, we have to tolerate those folks who have this unhealthy penchant for new stuff ...

[PDR1]

What ever happened to bark and charcoal?

It was OK, but as soon as the digital version came along and replaced it with bytes we all found the bark was worse than the byte.

[I'll fetch my coat]

PDR

[aroa]

Sunny The Book Stick and Rudder by Langwiesche ? or like spelling,,gives detailed explanations for the basics in the days of old when the rudder bar got plenty of use tp produce a balance turn.
Been in Tiger ? the old Turn and Bank will show it all very distinctly. Might have to wait until its warmer !!

[john_tullamarine]

we all found the bark was worse than the byte.

Oh, full marks deserved, indeed !

Well done, good sir.

[Sunfish]

I will reread stick and rudder. My other alternative is to fly with a border collie co pilot

[desert goat]

You don't need to get caught up in all the centre of gravity vs centre of lift stuff. Just use your feet to keep the aircraft aligned with the relative airflow. Like so. (Skip to 5:50 for the key point if you don't want to sit through the whole thing.)
https://m.youtube.com/watch?v=Q1975ehziOg

[SPUDO]

Sunny,

Here is a simple demonstration to help with your understanding of slipping and skidding. The important thing about this demonstration is that it makes no mention of technical concepts such as lift, balanced forces, etc. It doesn't even involve aeroplanes.

When you drive to work tomorrow morning, take your cup of coffee, but before departing, drink it down to a level where the cup is half full. Then, whilst driving, hold the cup with one hand. As you go around corners, you will have to give the cup a bank angle so as to keep the coffee level relative to the orientation of the cup. You will find that the higher the speed in the turn, or the sharper the turn, the more steep the bank angle must be.

Going round a corner, the cup should be banked, and if banked at the correct angle, the liquid level will be level with the cup edges, so's to speak.

You can think of the bank angle of the cup as akin to the bank angle of the plane. And when the liquid is level relative to the cup, the "ball" is centered. The "skid" situation is thus very easy to see and grasp. The "slip" situation, too, but I'll leave that to you!

Good luck!