"Step on the ball" confusion

This isn't specific to the F-14, but since the ball is so prominent on the dash it's easiest for me to demonstrate. I do not really understand how "step on the ball" works. In the video below, I did a right turn, followed by a reversal to a left turn, then returning level without using any rudder inputs whatsoever. Just watching how the ball reacts to my banks. Here's what I see:

Right turn

1. Ball swings LEFT, not right

2. Ball settles slightly right after bank

3. Ball settles neutral during the turn

Reversal to left turn

1. Ball swings RIGHT, not left

2. Ball settles slightly left after bank

3. Ball settles neutral during the turn

Rolling level (to the right)

1. Ball swings LEFT, not right

2. Ball swings right when my wings are level and nose is straight

The ball is telling me the opposite of what coordinated turn theory tells me, and it's not unique to the Tomcat. I observe this behavior to some degree in all my analog modules: Spitfire, Mustang, Kurfurst, Anton, and Saber.

Should I be ignoring the ball when it swings the opposite direction of my turn, or should my feet really be all over the place as the ball suggests?

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Did you try on the ground? there when turning left, the ball shld go right.

A displaced Ball means you’re slipping or skidding your turns.

https://www.experimentalaircraft.info/articles/slip-skid-indicator.php

A displaced Ball means you’re slipping or skidding your turns.

 

https://www.experimentalaircraft.info/articles/slip-skid-indicator.php

I think you missed my post and demonstration. I know I am slipping/skidding my turns. What I don't understand is why the ball is telling me to do the opposite of what articles like the one you linked tell me to do. I.e.:

Articles: RIGHT bank = ball moves RIGHT, therefore RIGHT rudder

DCS: RIGHT bank = ball moves LEFT, then back to the RIGHT, therefore.....what? I'm supposed to kick left rudder while banking right, and then switch to right rudder?

I suggest you have a look over there:

The Tomcat isn't as difficult as it seems. When at low AoA like in your video, you don't need a lot of rudder input, if any. You need a bit at really high bank angles, of course. One or two seconds ball slippings are not a problem, as soon as it centers itself immediately afterward. It's just the ball's inertia. At high AoA (let's say 15 units and above), you have to use the rudder in order to give bank angle, and then you step on the ball.

Does it answer to your question?

Nealius,

I was a step away from arrogantly making a video demonstrating coordinated turns, but I think you're right! The ball on the lower end of the Turn-and-Slip Indicator appears to be behaving backwards in turns.

I'm don't think it was always this way - perhaps something has changed with recent updates, but I do believe you are correct.

I suggest you have a look over there:

 

 

 

The Tomcat isn't as difficult as it seems. When at low AoA like in your video, you don't need a lot of rudder input, if any. You need a bit at really high bank angles, of course. One or two seconds ball slippings are not a problem, as soon as it centers itself immediately afterward. It's just the ball's inertia. At high AoA (let's say 15 units and above), you have to use the rudder in order to give bank angle, and then you step on the ball.

 

 

Does it answer to your question?

So the "step on the ball" rule only applies once settled in the bank, and any initial ball movement is from inertia and therefore should be ignored?

No, you step on the rudder when you initiate the roll too. You want to have the ball as long as possible centered at any time.

So the "step on the ball" rule only applies once settled in the bank, and any initial ball movement is from inertia and therefore should be ignored?

Not exactly.

No, you step on the rudder when you initiate the roll too. You want to have the ball as long as possible centered at any time.

Yes.

That's for the general theory. Fact is: some planes need more or less input, and most fighter planes don't need any at low AoA, except at very high bank angles.

The initial lag of the ball due to inertia obviously doesn't occur on digital turn and slip indicators.

But I need to use rudder in the direction of roll when initiating roll, regardless of whether the ball swings the opposite side or not, correct?

Most fighters won't need rudder input when initiating roll at low AoA. So you won't touch the rudder at all when initiating the roll. You'll use it if your bank angle makes the ball slip. At high AoA, you'll need the rudder to initiate the roll. So you'll use it whether the ball swings the opposite side or not (well, it will anyway). And once the turn engaged, you'll step on the ball.

Gotcha. Is there any standard definition of "high AoA." I understand in the Tomcat above 15 units is considered high, but what about the ~10 range?

It's not a simple low=no rudder to high=rudder case. The more AoA, the more rudder you need. Check the ball to see how much would be needed at which AoA.

I think, and I might be talking out of my ass here...

That the ball is only good for coordinating the turn when you are already on the turn with neglectible roll. I belive when rolling the ball will always be spun to the outside because of centrifugal forces, even though what you should do is use inside, into the roll, to counter adverse yaw.

Most fighters won't need rudder input when initiating roll at low AoA. So you won't touch the rudder at all when initiating the roll. You'll use it if your bank angle makes the ball slip. At high AoA, you'll need the rudder to initiate the roll. So you'll use it whether the ball swings the opposite side or not (well, it will anyway). And once the turn engaged, you'll step on the ball.

You do in the Tomcat...

Experiment and observe how the ball reacts to your banks and rudder inputs at different angles of attack. The F-14 has it's quirks. The best way of learning this skill actually doing it. Start at low AoA and bank to a side as you give either opposite or same side rudder...... just a bit of it. Then level off. Now go the other way. See how the ball responds. Now increase AoA and do the same. Do that until you reach 15 t o20 units.

Everything after that will just be practicing and applying what you observed.

Experiment and observe how the ball reacts to your banks and rudder inputs at different angles of attack. The F-14 has it's quirks. The best way of learning this skill actually doing it. Start at low AoA and bank to a side as you give either opposite or same side rudder...... just a bit of it. Then level off. Now go the other way. See how the ball responds. Now increase AoA and do the same. Do that until you reach 15 t o20 units.

 

Everything after that will just be practicing and applying what you observed.

I think people are missing the OPs point. He's not asking for flight lessons, he's asking if the ball behaviour is correct or needs to be reviewed.

Agreed. OP is wondering about ball physics/modeling. I never regard the ball in dynamic situation. It's a ball in a fluid. Shake it up and who know where its gonna be. Stabilize the aircraft and wait a bit for the ball to settle. Works the same way irl.

~Bailey

Note: When you are turning right, it's not the ball that swings left. It's you that's swinging right, relatively. Remember, things like the compass, turn and slip, and other analog instruments cannot predict your actions, so they lag. That's how I think of it. I look forward to when you explore how straight and level acceleration/deceleration effects the compass differently depending on which cardinal heading you are facing. It's pretty trippy.

~Bailey

You’re also sitting well forward of the vertical axis of the aircraft.

Yaw the nose left and the ball isn’t really going right, it’s initially staying where it is.

Much, much longer moment arm than in your average C172 or PA-28.

Agreed. OP is wondering about ball physics/modeling. I never regard the ball in dynamic situation. It's a ball in a fluid. Shake it up and who know where its gonna be. Stabilize the aircraft and wait a bit for the ball to settle. Works the same way irl.

~Bailey

Yea, it's like a gyro gunsight. You have to fly a steady course for a while before it stabilizes and gives you reliable information.

I'm a little late to this party but it sounds like the ball is reacting to turns properly. The F-14 only has adverse yaw at high AoA, as mentioned, and under those conditions the ball moves in the direction of roll. At low AoA it's actually proverse, in which case the ball moves opposite the turn.

Roll spoilers were actually designed to prevent adverse yaw in the first place but I guess, like anything, they have their limits. Could be they overcompensate at low AoA so that the sweet spot where they work properly is in a more usable range for a fighter plane, as opposed to an airliner that's never going to see that kind of AoA.

You boys are spot on with your explanations today, really on the ball... ;)

Also, this is one of those Simulator issues. In a real plane you feel what you need to do well before seeing what the ball does.

Coordinated is better, your bullets go where they're supposed to, and the plane doesn't flop around and such as it plows sideways through the air.

But it's just not something a sim can do real well.

I think people are missing the OPs point. He's not asking for flight lessons, he's asking if the ball behaviour is correct or needs to be reviewed.

Oh, i know, but i was trying to give the OP any lessons, just trying to get him to observe the differences between ball behavior at different angles of attack and eventually come to this conclusion:

I'm a little late to this party but it sounds like the ball is reacting to turns properly. The F-14 only has adverse yaw at high AoA, as mentioned, and under those conditions the ball moves in the direction of roll. At low AoA it's actually proverse, in which case the ball moves opposite the turn.

 

Roll spoilers were actually designed to prevent adverse yaw in the first place but I guess, like anything, they have their limits. Could be they overcompensate at low AoA so that the sweet spot where they work properly is in a more usable range for a fighter plane, as opposed to an airliner that's never going to see that kind of AoA.

:thumbup: