Runway Sideslip Drill?

[FastEddieB]

Uploading to YouTube now. Link coming soon.

I think it does show that I managed to do what I thought I could, though I doubt any minds will be changed.

What a great day for flying in the snowy N GA mountains!

 

[Henning]

You know, no one is trying to embarrass anyone or get one up. Some of us just couldn't let pass some of the basics being disputed that we thought were indisputable. We've tried to use logic and some authoritative sources to bolster our points.

But when you make these statements and put some of them in caps, you are just doing to yourself what we are trying not to do.

Are you in So Fla? I would love to take you up and demonstrate the point. A slip in and of itself will not displace the aircraft from its inertial vector down the centerline of the runway. I can the row in a full slip and not move one inch side to side. If I make the plane move sideways in that slip, I have turned the plane, in order to make the plane go straight down the runway I have to apply a force to the inertia in the opposite direction equal to the turning force I put in to shift the vector before. Where the nose aligns in all this is wholly irrelevant, I can keep it pointed on any point in a wide range through the whole process, but the slipping is not causing the process to happen, it is the horizontal component of lift generated. You will trace the same path over the ground as with coordinated turns except they will be stacked together tighter. If at any time while moving away from the centerline you neutralize the controls, you will point, and continue in that direction.

Newtons laws of motion, read them up.

 

[dmspilot]

Why are some so obsessed with what happens when you neutralize the controls? Nowhere does the "sideslip drill" say anything about neutralizing the controls.

If you have a problem with the sharp angles when the flight path changes, well, it's a simplified diagram. Of course it doesn't change instantly.

 

[FastEddieB]

For your viewing pleasure (best viewed in HD):

https://www.youtube.com/watch?v=D4gnd_gF9F4

Two runs of the exercise sandwiched between a takeoff and a landing. Slight variable left crosswind. What I was trying to say I could do, this shows me doing it.

Note the yaw string. First time I tried slipping I was surprised it moves "opposite" the ball, though if I had thought about it that's logical.

 

[Henning]

Why are some so obsessed with what happens when you neutralize the controls? Nowhere does the "sideslip drill" say anything about neutralizing the controls.

If you have a problem with the sharp angles when the flight path changes, well, it's a simplified diagram. Of course it doesn't change instantly.

Look at the progression of the three positions as they track sideways. In order to stop moving sideways at the edge of the runway, the bank will have to reverse at the mid point to check the inertia of the mass of the airplane by the edge of the runway. That is not holding a slip, that requires a transition through a skid to keep the nose pointed down the runway. All one is doing is making an uncoordinated S Turn hold the nose in a fixed direction. Entering the skid to stop the inertia is a spin hazard.

 

[vintage cessna]

Are you in So Fla? I would love to take you up and demonstrate the point. A slip in and of itself will not displace the aircraft from its inertial vector down the centerline of the runway. I can the row in a full slip and not move one inch side to side. If I make the plane move sideways in that slip, I have turned the plane, in order to make the plane go straight down the runway I have to apply a force to the inertia in the opposite direction equal to the turning force I put in to shift the vector before. Where the nose aligns in all this is wholly irrelevant, I can keep it pointed on any point in a wide range through the whole process, but the slipping is not causing the process to happen, it is the horizontal component of lift generated. You will trace the same path over the ground as with coordinated turns except they will be stacked together tighter. If at any time while moving away from the centerline you neutralize the controls, you will point, and continue in that direction.

Newtons laws of motion, read them up.

Dude, if you put it in a full slip and don't move sideways that is becuase you are in a FORWARD slip. You guys keep saying there is no difference in the type of slips. A SIDE slip you will definitely move you sideways. This is why no instructor should say a slip is just a slip, they have different directions of movement.

Thing is, you don't have to take my word for it, this is in every flying text book there is including the FAA Airplane Flying Handbook.

 

[Henning]

For your viewing pleasure (best viewed in HD):

https://www.youtube.com/watch?v=D4gnd_gF9F4

Two runs of the exercise sandwiched between a takeoff and a landing. Slight variable left crosswind. What I was trying to say I could do, this shows me doing it.

Note the yaw string. First time I tried slipping I was surprised it moves "opposite" the ball, though if I had thought about it that's logical.

It sure looks like your ball swings through a skid at the reversal.

 

[FastEddieB]

That is not holding a slip, that requires a transition through a skid to keep the nose pointed down the runway.

It sure looks like your ball swings through a skid at the reversal.

My panel arrangement is near perfect for this, with the ball - and a very sensitive ball - front and center at the top of the panel.

I just watched my video again and really tried to see the skid you're talking about - I don't. I seem to roll briefly through coordinated flight (ball centered) on my way from one skid to the other.

One way to define a skid is too much rate of turn for a given angle of bank. Since my entire maneuver was accomplished with virtually no heading change, and hence no turn (at least by common definition), I don't see how the rate of turn could be too high for anything, since there is none.

Of course, maybe by redefining both what a turn is and what a skid is your position will start to make sense to me!

 

[vintage cessna]

For your viewing pleasure (best viewed in HD):

https://www.youtube.com/watch?v=D4gnd_gF9F4

Two runs of the exercise sandwiched between a takeoff and a landing. Slight variable left crosswind. What I was trying to say I could do, this shows me doing it.

Note the yaw string. First time I tried slipping I was surprised it moves "opposite" the ball, though if I had thought about it that's logical.

Nice job Eddy.

 

[Henning]

My panel arrangement is near perfect for this, with the ball - and a very sensitive ball - front and center at the top of the panel.

I just watched my video again and really tried to see the skid you're talking about - I don't. I seem to roll briefly through coordinated flight (ball centered) on my way from one skid to the other.

One way to define a skid is too much rate of turn for a given angle of bank. Since my entire maneuver was accomplished with virtually no heading change, and hence no turn (at least by common definition), I don't see how the rate of turn could be too high for anything, since there is none.

Of course, maybe by redefining both what a turn is and what a skid is your position will start to make sense to me!

I must have been looking at the wrong thing down to the left. The fact that you went through a coordinated turn at the edge proves what we were saying. You had to straighten out the vector.

 

[vintage cessna]

I must have been looking at the wrong thing down to the left. The fact that you went through a coordinated turn at the edge proves what we were saying. You had to straighten out the vector.

Was it Penn and Teller flying the airplane or was it Eddie? He side slipped left and the airplane moved sideways to the left, then he side slipped right and the airplane moved sideways to the the right.

He said his heading never changed, so no turn was required, nor did any take place, to change the movement from side to side.

 

[Silvaire]

I must have been looking at the wrong thing down to the left. The fact that you went through a coordinated turn at the edge proves what we were saying. You had to straighten out the vector.

 

[Henning]

I'm done. People just are not understanding Whifferdill's and my objection to 'the drill' which was just proven, but since the ends were not allowed to stabilize on their heading before reversal, it just maintained the confusion of the original video.

 

[pilot1956]

Eddie - nice video.

Consider the following: During the runway slip drill, you have a crosswind from the right (for example), and you are flying in a slip with right wing low and left rudder pressure in order maintain straight flight (i.e., heading and track are not changing over time). Your have enough slip entered to that track and heading are aligned with the runway. In in order to fly from the left side of the runway to the right side of the runway in a slip, the right wing must drop further and more left rudder must be applied. At that point, it is not possible for the heading and track to both be aligned with the runway centerline. In fact, the nose will yaw left and the plane will drift to the right. This is not what is depicted in the diagram above.

 

[FastEddieB]

The fact that you went through a coordinated turn at the edge proves what we were saying.

Who knows, since I honestly have no idea what you were saying.

It just feels to me like I just did something that somebody here said was impossible to do.

But it was pretty clear no demonstration would work to change minds.

Just hope my video made some things a little clearer for some forum members.

If so, my work here is done!

 

[vintage cessna]

I must have been looking at the wrong thing down to the left. The fact that you went through a coordinated turn at the edge proves what we were saying. You had to straighten out the vector.

Do you see how, when at the edge he comes out of the slip, flys wings level for a moment, then slips the other way? Do you see how the nose of the acft remained parallel to the centerline? There is no turn anytime.

 

[FastEddieB]

The fact that you went through a coordinated turn at the edge proves what we were saying.

(bolded mine)

I fly a maneuver where I start it with my longitudinal axis aligned with the runway - approximately 200º.

I then do a bunch of stuff, all while still headed 200º. Finish up still on 200º.

My allegation would be a constant heading implies no turn - at least not a turn in the way I would assume most of us understand it - a change of heading.

And you can't skid without a turn, so no turn, no skid - literally by definition.

 

[Lindberg]

Just hope my video made some things a little clearer for some forum members.

If so, my work here is done!

Well, I might have been starting to question my sanity just a little bit, and you restored me, so job well done. even if you don't convince anyone else of anything. That is a great runway for the demonstration.

Nice landing, too.

 

[dmspilot]

Well, scientifically speaking any change in direction is a turn. But I thought Henning was trying to say that you can't perform the sideslip drill without changing heading. Honestly at this point I don't even know what his argument is exactly because it is so obtuse.

 

[Henning]

Do you see how, when at the edge he comes out of the slip, flys wings level for a moment, then slips the other way? Do you see how the nose of the acft remained parallel to the centerline? There is no turn anytime.

Of course there is a turn, that the wings switch proves there is a turn because they provide a horizontal component of lift and that is the definition of a turn. Where the nose is pointed is irrelevant to whether the plane is turning or not. You can make the nose point where ever you want at any given time, but to travel in a straight line again, there has to be a reversal.

Now check this out, because it is the issue... The line as drawn in "The Drill" is a straight line. That is the impossibility, that line will trace an S pattern.

 

[whifferdill]

Eddie, that's a good demo. Kudos to you for actually going up and doing some flying. Glad you survived the snowpocalypse and your runway is cleared.

Yes, you did the runway drill, as I expected you would be able to. I never said it couldn't be done, and I've said I could perform the same thing in the Pitts.

My points are still the same as Hennings - that this requires a slipping turn to cause the initial flight path shift, and that you must do another slipping turn to redirect that flight path. The bank and turn angles are so shallow here that it's hard to really see what we're talking about. Don't think I'm trying to claim you did not perform what you set out to do. You did.

We simply take issue with the dynamics of movement associated with that drill picture - especially the flight path being redirected as the slip is neutralized. Maybe the originator of that diagram did not truly mean to imply this, but it sure seems like it. Due to control effectiveness. The Pitts is a good airplane to show this. I could go up and start a large deflection slip so that the nose is aligned with the runway, but the airplane is flying a path at a significant angle to it. I can then neutralize the slip and the airplane will continue to fly along that same angled path. To keep the nose on that same heading while redirecting the flight path back on runway would require a slipping turn to redirect that angled flight path. This would be easy to show.

That's it. It's a simple argument over how the picture and description are presented. Some feel it's splitting hairs, others feel it comes down to either presenting the physics correctly or incorrectly. But on the internet even physics is a matter of opinion. That last comment was not directed toward you.

 

[vintage cessna]

Who knows, since I honestly have no idea what you were saying.

It just feels to me like I just did something that somebody here said was impossible to do.

But it was pretty clear no demonstration would work to change minds.

Just hope my video made some things a little clearer for some forum members.

If so, my work here is done!

https://m.youtube.com/watch?v=NzlG28B-R8Y

 

[vintage cessna]

.


My points are still the same as Hennings - that this requires a slipping turn to cause the initial flight path shift, and that you must do another slipping turn to redirect that flight path.

This is what Langewieche says on crosswind landings- "One method is to dip the left wing slightly down by aileron, at the same time KEEPING IT FROM MAKING A LEFT TURN by putting on some right rudder. This results in a SIDESLIP toward the left."

Caps are mine of course. He says you keep it from making a turn. You have pointed to Langewieche as THE expert on this stuff. Do you now say he doesn't "get it". Only you and Henning? And besides, why would you have to start this with a slipping turn, why not just a normal coordinated turn?

 

[Henning]

This is what Langewieche says on crosswind landings- "One method is to dip the left wing slightly down by aileron, at the same time KEEPING IT FROM MAKING A LEFT TURN by putting on some right rudder. This results in a SIDESLIP toward the left."

Caps are mine of course. He says you keep it from making a turn. You have pointed to Langewieche as THE expert on this stuff. Do you now say he doesn't "get it". Only you and Henning? And besides, why would you have to start this with a slipping turn, why not just a normal coordinated turn?

Let go of the slip after you start moving sideways, and what direction do you end up pointing? Another direction right? That is the definition of a turn.

 

[dtuuri]

For your viewing pleasure (best viewed in HD):

https://www.youtube.com/watch?v=D4gnd_gF9F4

Good job, victory is ours! No amount of pseudo-physics can trump it. Between the yaw string and inclinometer the proof is irrefutable.

For advanced students, also consider a twin-engine plane that loses an engine in straight flight. A fast-acting pilot can maintain heading and zero bank as thrust is lost, so any passenger aboard would only detect sound changes and hardly any kinesthetic sensations at all. The ball would continue to be centered, but the yaw string would show a slip toward the dead engine and the heading held constant. By banking toward the good engine the slip goes away, the ball moves out of center and the heading remains constant.

dtuuri

 

[Vance Breese]

For your viewing pleasure (best viewed in HD):

https://www.youtube.com/watch?v=D4gnd_gF9F4

Two runs of the exercise sandwiched between a takeoff and a landing. Slight variable left crosswind. What I was trying to say I could do, this shows me doing it.

Note the yaw string. First time I tried slipping I was surprised it moves "opposite" the ball, though if I had thought about it that's logical.

Nicely done!

I fly with a yaw string (no ball) and my substitute for "step on the ball" is to imagine the yaw string is a snake with the head at the bottom. Step on the head or the string is pointing at the pedal to apply pressure to.

 

[whifferdill]

Let go of the slip after you start moving sideways, and what direction do you end up pointing? Another direction right? That is the definition of a turn.

He's foaming at the mouth at this point, no point in trying further reasoning.

 

[whifferdill]

Good job, victory is ours!

LOL. Glad you won. Remind us what you won?

 

[Henning]

LOL. Glad you won. Remind us what you won?

Why don't you go back up and mak a clear video of what we are talking about. Start at one side, toss it into a slip and get it traveling across the runway, then release the slip and let it keep on flying in coordinated wings level flight.

 

[vintage cessna]

Let go of the slip after you start moving sideways, and what direction do you end up pointing? Another direction right? That is the definition of a turn.

I suppose by let go you mean releasing pressure from the rudder and not bring the ailerons back to nuetral? Then I would certainly START a turn at that point. But if you come out of the side slip by returning rudder and aileron to nuetral there should be no change in the direction the nose was facing. Where is the nose pointing (in a side slip) before you let go? Straight on , right? So no change in direction during side slip = no turn.

 

[BillTIZ]

Nice video, I just tripped over this post. 186 in two days about a sideslip.

But me thinks you are overthinking this?
Do it all the time in the glider on tow. Wings remain level, nose (fuselage centerline) is always parralle to the tow plane and direction of flight. Rudder only to slide from left side to right side, corners for boxing the wake. It's a a rudder slide, with opposite aileron to keep the rudder input from initiating a bank. Keep the wings level.

 

[Henning]

I suppose by let go you mean releasing pressure from the rudder and not bring the ailerons back to nuetral? Then I would certainly START a turn at that point. But if you come out of the side slip by returning rudder and aileron to nuetral there should be no change in the direction the nose was facing. Where is the nose pointing (in a side slip) before you let go? Straight on , right? So no change in direction during side slip = no turn.

No, get off the rudder and go wings level. Neutralize the slip into coordinated wings level flight with no reversal.

 

[dtuuri]

LOL. Glad you won. Remind us what you won?

Why, braggin' rights of course, what else is there? Oh yeah, a beer!

dtuuri

 

[vintage cessna]

He's foaming at the mouth at this point, no point in trying further reasoning.

Have you denounced Langewieche as a regurgitating monkey yet?

 

[whifferdill]

Why don't you go back up and mak a clear video of what we ate talking about. Start at one side, toss it into a slip and get it traveling across the runway, then release the slip and let it keep on flying in coordinated flight.

I will. I'll also wait for a real x-windy day and slip in both directions without drifting off runway track. You know, since that wing into the wind is what is "canceling the x-wind".

Have you denounced Langewieche as a regurgitating monkey yet?

LOL. Nope just the folks who get all worked up over side vs. forward slip. That was NOT Mr. Langeweische, you may recall if you actually read anything I wrote. There was no such nonsense back then. Wipe your mouth, you're drooling now.

 

[vintage cessna]

I will. I'll also wait for a real x-windy day and slip in both directions without drifting off runway track. You know, since that wing into the wind is what is "canceling the x-wind".

I guess you have rejected Langewieche, pretty fickle of you.

 

[whifferdill]

I guess you have rejected Langewieche, pretty fickle of you.

This is the problem with the internet. People get so butthurt that their brains shut down. Where does Mr. Langeweische say that you cannot slip in both directions without drifting off track? But really, you're in no condition to try to actually continue an intelligent discussion.

 

[dtuuri]

No, get off the rudder and go wings level.

He did that. The ball and yaw string went the other way because he did it. Nobody is saying 'just let go'. We're saying 'neutralize'. In this case, being a drill, he went right into a sideslip the other way (didn't momentarily stop on the centerline as per the diagram--but he could have).

dtuuri

 

[Henning]

I will. I'll also wait for a real x-windy day and slip in both directions without drifting off runway track. You know, since that wing into the wind is what is "canceling the x-wind".



LOL. Nope just the folks who get all worked up over side vs. forward slip. That was NOT Mr. Langeweische, you may recall if you actually read anything I wrote. There was no such nonsense back then. Wipe your mouth, you're drooling now.

It would be best to demo in no wind as well to make clear what effects what.

 

[vintage cessna]

I will. I'll also wait for a real x-windy day and slip in both directions without drifting off runway track. You know, since that wing into the wind is what is "canceling the x-wind".



LOL. Nope just the folks who get all worked up over side vs. forward slip. That was NOT Mr. Langeweische, you may recall if you actually read anything I wrote. There was no such nonsense back then. Wipe your mouth, you're drooling now.

No such nonsense back then? And you say other people have reading comprehension problems? He ( Lang.) describes a side slip just as other people have tried to describe it to you. In fact, he describes a side slip the same way the Airplane Flying Handbook does. What goes on in your head , who knows.