Lindberg
Final Approach
It's more like the downwind turn, where people actually think the airplane cares what the wind is doing.
Did you watch the videos posted in the other thread, which clearly show aircraft moving laterally.
The King video seems to perfectly demonstrate the side-slip drill, and the nose never changes direction. So whether or not you want to call what you're seeing a "turn," but you're wrong about the controls.
It's like Henning and whifferdill are speaking another language. Seriously, I'm lost. Being able to slip left and right is dependent upon how strong the wind is? You realize the airplane doesn't know there is any wind right?
I've kept saying wind is irrelevant here.
The only way to mimic the Runway Sideslip Drill as it is drawn is if you have a crosswind.
Because you don't change the flight path, the wind does.
BINGO! You have to have the crosswind. The drill is not predicate on a crosswind.
the cross wind is changing your flight path. Your slip is altering your relationship to the wind, not the relationship to your flight path.
There is no such thing as a side slip if there is no crosswind, because a side slip is defined as a slip used to correct for a crosswind.
Maybe I don't really understand the argument being made. Are you people really trying to say it's not possible to fly sideways in a slip? Isn't that what a slip is?
Consider the attached image (sorry for my amateur artwork).
... but to change the path in a no wind situation, you still need to turn.
It is not possible to displace your flight path sideways using a slip except as such to regulate your speed in relationship to a crosswind. That's more involved than 'flying sideways' as it not only references the alignment of the plane, but the path as well. You can change the alignment of the plane no problem, but to change the path in a no wind situation, you still need to turn.
BTW, here is the FAA Handbook illustrating the difference between forward and sideslip. See the difference? Sure hope nobody forgets which is which when it comes time to make your next x-wind landing.
Don't forget the yaw string.
dtuuri
It sure looks possible to me.
You may be right, but the more I think about this, the more I question it.
When you bank the plane, you create a horizontal component of lift that in the absence of one other phenomena (weathervaning), would simply translate the plane to the side as it moved forward, causing it to move along an angled line relative to the body of air in which the plane is moving forward.
If you allowed the tail to weathervane in a normal fashion, and with the RW coming in from an angle due to the angled movement, the plane would continually try to turn into the RW and would indeed follow a curved path relative to the body of air. The weathervaning happens quickly, I believe, but it's not instantaneous.
It's cause (horizontal component due to bank from aileron) and effect (weathervaning of tail, followed by curving flight path). If desired, I think, you can prevent the effect altogether (using rudder).
Therefore, if you used opposite rudder to prevent the weathervaning, you could make the plane continue to fly straight relative to the body of air (e.g. to lose altitude when too high on final and while flying on the runway centerline on a calm day) or, by judicious application of just a bit too little or a bit too much of the opposite rudder, cause (or allow) the horizontal lift component to translate the plane along an angled path relative to the body of air (and runway since it's a calm day).
Maybe when you apply just a bit too little or too much rudder, the tail necessarily weathervanes to that same small degree, like a regular turn, and this all becomes a matter of philosophy on when the plane is turning, versus translating,... But I'm not sure I can noodle that yet.
Of course, you could also keep the same rudder, and apply a bit more or a bit less aileron - same difference.
Just some thoughts...
(Edited to make a little more sense, maybe)
The wind is irrelevant. The aerodynamics are the same whether there is a wind or not.
Maybe I don't really understand the argument being made. Are you people really trying to say it's not possible to fly sideways in a slip? Isn't that what a slip is?
Consider the attached image (sorry for my amateur artwork).
You are forgetting one factor, when yo put in the opposite rudder, you create an opposite horizontal component of lift with the fuselage that cancels the horizontal component of lift of the wing. As soon as you unbalance the rudder and aileron from a straight line, the path followed will start to curve.
Wiff, you've rotated the picture for the forward slip, that's not how it's depicted in the book. Think of up as being the direction of the runway because that's the only difference. The control inputs are exactly the same and in a forward slip you clearly understand that the airplane is flying laterally in reference to it's longitudinal axis so why would it be any different if you used those same exact control inputs but kept the nose pointed down the runway? Honestly, how could it be different?
As I said in the other thread the purpose of this exercise is to develop control coordination. You want to slowly rock the wings back and forth while keeping the nose dead steady on a constant heading. Believe me the aircraft will enter a slip and the flight path will change in the direction of the slip. It has too.
Here's another:
EDIT: Any "turn", meaning curved flight path entering the slip, is because you can't immediately go from level wings to banked in zero seconds, so the amount of deflection is changing while the plane is rolling resulting in a slight (very slight) curve or "turn" to some folks.
dtuuri
It's not the "turn" of the plane that is the issue, the flight path will ground track as a curve whenever there is sideways motion to the relative wind. You are still making a turn, you are just making an uncoordinated turn.
The Pitts video doesn't show sideways movement because of the crosswind.
Nope. This "drill" is something CFIs everywhere do.
I think some of us need to reread Stick and Rudder.
...Some here are getting hung up on this heading maintaing exercise, which I think is clouding things. Here's an easy exercise anyone can do next time they fly -
Fly along a straight line in a slip that's balanced such there there is no turning or movement of the flight path - how my video starts. Then either ADD aileron or REDUCE the rudder to make the airplane DO something new. Now MAINTAIN those EXACT inputs. The airplane will fly an indefinite curved flight path until you STOP it and rebalance the slip.
...Fly along a straight line in a slip that's balanced such there there is no turning or movement of the flight path - how my video starts. Then either ADD aileron or REDUCE the rudder to make the airplane DO something new. Now MAINTAIN those EXACT inputs. The airplane will fly an indefinite curved flight path until you STOP it and rebalance the slip.
Do. Shall I quote what Mr. Langeweische has to say about slips? Not only does he not discuss the 'sideslip' drill, he did not even invent names for different types of slips as we later did. There was no forward or sideslip nonsense. Only the pure basics, beautifully written, simple and unequivocal.
There is no such thing as a side slip if there is no crosswind, because a side slip is defined as a slip used to correct for a crosswind.
[T]he flight path will ground track as a curve whenever there is sideways motion to the relative wind.
Well once again we are not on the same page because the constant heading slip is exactly what that is. Look at the King video, just from 00:22 to 00:30 - he has put the aircraft in a slip to the left while keeping the nose on a constant heading. He could have held that and flown to the next county without ever changing the heading or turning.
Wait a minute here. The slip is a balanced configuration, if you want to ADD aileron then you're going to have to ADD rudder to maintain that balance. That's how you keep tracking the runway in a forward slip without turning. That's exactly what is happening in the side slip, the only difference is that the nose has not changed heading. In either case the lift is offset, that's why the airplane is flying sideways. If the lift were balanced it would go in the direction the nose is pointed.
I posted several links in the previous discussion about this, one of them explained how to do it in a DC3. All you need to do is Google "constant heading slip" and you'll find plenty to read.
Furthermore the whole point of the exercise is to develop cross control coordination. If you think you're going to just go up and yank the stick full left and full right and keep the nose pinned on a constant heading then you're darn good because it takes practice. That's why it's called an exercise or drill. Trying to demonstrate it unrehearsed with a 30 second video in a Pitts at 90 knots 30 feet over a skinny runway isn't the best way to get good results. No offense Wiff I'm sure you're a great pilot but this takes a bit of patience and graceful finesse. Your Pitts is short coupled with very little dihedral and although it will do it it's probably not the best platform to make a demonstration video with.
I think the King video should have put this to rest but apparently nothing ever will.
Wait a minute here. The slip is a balanced configuration, if you want to ADD aileron then you're going to have to ADD rudder to maintain that balance. That's how you keep tracking the runway in a forward slip without turning. That's exactly what is happening in the side slip, the only difference is that the nose has not changed heading. In either case the lift is offset, that's why the airplane is flying sideways. If the lift were balanced it would go in the direction the nose is pointed.
So it sounds like you crab down final and make turns to to maintain runway alignment. My tailwheel instructor would have beat me on the back of the head if I crabbed a taildragger on final. All the tailwheel instructors I know teach keeping the nose pointed down the runway on final and adjusting position by slipping, whether there is a crosswind or not.The problem is when you introduce this stupid 'runway drill' diagram AS DRAWN. It depicts a flight path change. I've never needed to make a flight path change transitioning from coordinated flight to slip on approach to a x-wind landing. That initial flight path change as shown in that drill diagram requires an unbalanced, turning slip for a few moments. If we disagree on this simple point, then so it will remain that way. That silly drill has no bearing on realistic handling of the controls on approach to a x-wind. I've landed in plenty of x-winds, and never done it.
It's not the "turn" of the plane that is the issue, the flight path will ground track as a curve whenever there is sideways motion to the relative wind. You are still making a turn, you are just making an uncoordinated turn.
Despite the fact that your Pitts likely doesn't fly like most non-aerobatic monoplanes...
...I strongly suspect that you could perform this drill if you understood it, and that you're imposing some constraint that doesn't exist in anyone else's mind. Many of us have said that we've done this, and you've essentially called us all liars or stupid. You've been shown videos of it, and still claim it's impossible. So what's left?
This seems to be rendering the argument in such a way as to make it impossible to counter.
A diagram was given, showing a plane flying down a runway on a constant heading, but moving left and right in the process. The path over the ground would be roughly a continuous "s".
That is what was deemed impossible, and that I'm purporting is not only possible but straightforward - as the King video showed.
If the position is "It's impossible to fly an "s" pattern over the ground without turning" and then define "turning" to be a change in the path over the ground, that's making it a fool's errand - you've just defined "turn" in such a way as to render your position inarguable.
Or I'm totally missing what's being proposed here.
I just fear I'll go out in a little while, fly the maneuver shown in the diagram, and someone will say "But you turned when your ground track changed!" in spite of the fact that I maintained runway heading throughout.
Nope. This "drill" is something CFIs everywhere do. Unless you're trolling, stop confusing the newbies with this nonsense. For them, seeing should be believing. The King video is spot on. The Pitts video doesn't show sideways movement because of the crosswind.
dtuuri
My tailwheel instructor would have beat me on the back of the head if I crabbed a taildragger on final.
However, if the King video is not enough, what ever you post certainly won't be, guaranteed.
I honestly don't understand where the confusion is. A slip is a slip. Whether it's a forward slip or a side slip is only determined by the orientation with respect to the runway. If you put the runway on a turntable, entered a forward slip on final, and rotated it parallel to the heading of the aircraft, it is now a side slip.
Or is there some other issue I'm missing?
I honestly don't understand where the confusion is. A slip is a slip. Whether it's a forward slip or a side slip is only determined by the orientation with respect to the runway. If you put the runway on a turntable, entered a forward slip on final, and rotated it parallel to the heading of the aircraft, it is now a side slip.
Or is there some other issue I'm missing?
Yes. The issue is if in a forward slip ( bank, but no change in heading of the aircraft) whether the aircraft can move side ways through the air, that is, at a striaght diagonal line with no curve in the flight path , as in a turn.
...It is physically impossible to move an airplane "laterally" through the air at a constant heading. It is only possible to turn the airplane, which causes your heading to change.
No to both. This thread was about that slip drill diagram as drawn. Can't be more concise and clear about this than post # 74.