About Auto Throttle (Discussion)

[ravenzino]

When ATC (Auto Throttle Control) is enabled, we can see the throttle lever is moving back and forth indicating ATC function is now controlling the throttle.

However, I keep on wondering, is it really the behavior IRL? If you would design a system with this ATC function, will you rather keep the throttle lever steady for the pilot to operate all the button and slew controls on it?

 

If the current behavior is exactly what happens on RL Hornet, can someone enlighten me:

1. How can pilot control things like TDC in a smooth way when throttle is constantly moving as a result of ATC?

2. How can pilot prevent breaking ATC when he/she is operating those controls on the throttle resulting in somehow blocking the movement of it?

 

 

Edit:

to add a little more sense to the two points above:

1. Pilot doing the fine slew adjustment by using finger to move the tiny TDC stick on the throttle lever, maybe just one last move, when the throttle suddenly moves a bit backward, and forward, and backward again, and forward again...

2. "Damn you, throttle lever, don't move!" so pilot make a dead grip on the throttle lever, so that it doesn't move, so the pilot can perform precise control on the TDC mini stick. Due to large force applied on the throttle lever to keep it steady, ATC might likely to disengage...

 

One more note to make here: when in game, the throttle does move relatively often even in level flight when ATC is engaged.

Edited August 9, 2019 by ravenzino

[bbrz]

It's the same like the auto throttle in e.g. a 737, 767, etc. which means an electric motor is moving the throttles.

 

You can't 'break' it. If you apply force to the throttles, or you hold them, the ATC will disengage.

 

Since you always have the hand on the throttles, there's no problem to operate the switches the same way as usual when manually controlling the throttles.

Edited August 9, 2019 by bbrz

[ravenzino]

It's the same like the auto throttle in e.g. a 737, 767, etc. which means an electric motor is moving the throttles.

 

You can't 'break' it. If you apply force to the throttles, or you hold them, the ATC will disengage.

 

Since you always have the hand on the throttles, there's no problem to operate the switches the same way as usual when manually controlling the throttles.

 

By 'break', I mean disengage.

 

It's understandable on civilian aircrafts, since once auto throttle is enabled, pilot is not supposed to keep his/her hand on it, and there's nearly nothing on the throttle lever to operate anyway.

 

Now with the Hornet, when you are operating things like TDC, your hand will be holding the throttle, and will inevitably apply some force on it. Otherwise, I don't see a way of operating TDC or other controls on the throttle while applying 0 force to the throttle to allow it being moved freely by the controlling motor...

[bbrz]

It's understandable on civilian aircrafts, since once auto throttle is enabled, pilot is not supposed to keep his/her hand on it, and there's nearly nothing on the throttle lever to operate anyway.

 

Now with the Hornet, when you are operating things like TDC, your hand will be holding the throttle, and will inevitably apply some force on it. Otherwise, I don't see a way of operating TDC or other controls on the throttle while applying 0 force to the throttle to allow it being moved freely by the controlling motor...

Especially if the autothrottle is controlling the throttles on 'civilian' airplanes it's required that you keep the hands on throttles at all times during the approach.

 

The go-around button and A/T disengage button are located on the throttles!

 

I would expect that you need to apply considerable force to disengage the ATC in the F/A-18.

 

On e.g. the 767 you can't disengage the auto throttle by manually moving the throttles since the auto throttle system immediately repositions the throttles as soon as you let go of the throttles.

But you need to apply considerable force to override the electric motors.

 

edit: force required to disengage ATC on the F/A-18 is approx 12lbs.

Edited August 9, 2019 by bbrz

[ravenzino]

Especially if the autothrottle is controlling the throttles on 'civilian' airplanes it's required that you keep the hands on throttles at all times during the approach.

 

The go-around button and A/T disengage button are located on the throttles!

 

I would expect that you need to apply considerable force to disengage the ATC in the F/A-18.

 

On e.g. the 767 you can't disengage the auto throttle by manually moving the throttles since the auto throttle system immediately repositions the throttles as soon as you let go of the throttles.

But you need to apply considerable force to override the electric motors.

 

edit: force required to disengage ATC on the F/A-18 is approx 12lbs.

 

Didn't see any button on B737 throttle lever... But thanks for the insight. I stand corrected on those points.

 

The main concern however remains valid. How can a pilot IRL slew TDC on the throttle in a smooth and precise way (operating TPOD for instance) when the throttle is constantly moving... and why it is designed that way (instead of remain steady) when the pilot is expected to perform a not-insignificant amount of operations on it...

 

Or, does RL Hornet pilot more than often disengage ATC before operating TDC...? Which seems to be a legit workaround, but again why can't allow them happen at the same time...

[bbrz]

I don't understand this question. Again, if you have to operate the TDC it doesn't make any difference if you move the throttles manually or the ATC moves them.

Furthermore the throttles shouldn't significantly move when e.g. in a steady state cruise.

During the approach things are different, but you shouldn't do anything else than flying the F/A-18 ;)

 

One advantage of the moving throttles during auto throttle operation is, that you have the immediate feedback about power changes and the present power setting without having to constantly scan the engine gauges.

Edited August 9, 2019 by bbrz

[David OC]

Didn't see any button on B737 throttle lever... But thanks for the insight. I stand corrected on those points.

 

The main concern however remains valid. How can a pilot IRL slew TDC on the throttle in a smooth and precise way (operating TPOD for instance) when the throttle is constantly moving... and why it is designed that way (instead of remain steady) when the pilot is expected to perform a not-insignificant amount of operations on it...

 

Or, does RL Hornet pilot more than often disengage ATC before operating TDC...? Which seems to be a legit workaround, but again why can't allow them happen at the same time...

 

 

You would use ATC when in level flight with autopilot on, when dropping GPS weapons, using TGP etc. The throttle would have little movement then. If your flying up and around then probably have it disconnected IRL.

 

[Cooler07]

The throttles don't move on Airbus after take-off thrust the auto-throttle system will activate.

[ravenzino]

You would use ATC when in level flight with autopilot on, when dropping GPS weapons, using TGP etc. The throttle would have little movement then. If your flying up and around then probably have it disconnected IRL.

 

 

Problem is, that little movement isn't helpful for pilot to perform some fine control of the mini stick (TDC) on the throttle.

 

Hence my question, is this really the behaviour on RL Hornet. If yes, why...

 

At the moment, it looks to me like a design flaw on RL Hornet which might not be a big deal, but certainly has room to improve...

[bbrz]

Problem is, that little movement isn't helpful for pilot to perform some fine control of the mini stick (TDC) on the throttle.

 

Hence my question, is this really the behaviour on RL Hornet. If yes, why...

 

At the moment, it looks to me like a design flaw on RL Hornet which might not be a big deal, but certainly has room to improve...

I've explained already why it is this way, that ATC behaves that way IRL, it's definitely not a design flaw and there's nothing to improve!

 

If you don't like throttle movements simply don't use ATC, same IRL.

 

Can't imagine that anyone would use ATC during anything but straight and level cruise and approach.

The F/A-18 is a combat aircraft and the ATC is just convenient for a few cases, but that's it.

 

As David said, if you are cruising straight and level, the throttles will certainly not move all the time.

 

Apart from that; how are you performing your fine inputs in case of turbulence, even without ATC?

Edited August 9, 2019 by bbrz

[cofcorpse]

When ATC (Auto Throttle Control) is enabled, we can see the throttle lever is moving back and forth indicating ATC function is now controlling the throttle.

However, I keep on wondering, is it really the behavior IRL?

 

Yes, it is correct behaviour. Real throttles moves by themselves when ATC is engaged.

Why it is done this way? There could be different reasons. Possibly, to indicate, that ATC is working right now.

While developing modules, we sometimes encounter things that seem to be illogical or impractical. Without full information and years of study of different subjects it is difficult to explain every single decision made by developers of original airplane.

[AvroLanc]

Yes, it is correct behaviour. Real throttles moves by themselves when ATC is engaged.

Why it is done this way? There could be different reasons. Possibly, to indicate, that ATC is working right now.

While developing modules, we sometimes encounter things that seem to be illogical or impractical. Without full information and years of study of different subjects it is difficult to explain every single decision made by developers of original airplane.

 

Personally I know I would find it disconcerting if the A/T didn't move, Airbus style...

 

In my aircraft the A/T servos move the physical throttles, and it's useful feedback to know what the systems are doing. You can also quickly override if you're not happy.

 

 

Any ETA on the Approach mode for ATC Cofcorpse?

[ravenzino]

I've explained already why it is this way, that ATC behaves that way IRL, it's definitely not a design flaw and there's nothing to improve!

 

I totally get what you are trying to explain around the why. But you didn't get the problem I'm trying to illustrate here.

Assuming you are trying to use your mouse to draw a perfect circle, while some one is pulling your mouse pad in small but constant movements... Now the mouse pad is the throttle, and the mouse is the TDC mini stick.

 

If you don't like throttle movements simply don't use ATC, same IRL.

 

I have no problem using ATC in DCS. My TM Warthog Throttle won't move because of ATC :)

This is more of a curious discussion rather than a serious debate to prove something is wrong... Hornet is a piece of fine art.

 

Can't imagine that anyone would use ATC during anything but straight and level cruise and approach.

The F/A-18 is a combat aircraft and the ATC is just convenient for a few cases, but that's it.

 

As David said, if you are cruising straight and level, the throttles will certainly not move all the time.

 

Well, that is exactly the problem scenario I'm talking about: in Wag's video, and in my armature practice, operating TPOD and locating the target would be done from distance. Imagine you are flying towards target waypoint on a set speed, ATC would likely be engaged. And now you need to start operating the TPOD...

If you look closely in game, you'll see the throttle actually does move fairly often even in level flight... not all the time, but fairly often...

 

Apart from that; how are you performing your fine inputs in case of turbulence, even without ATC?

 

Without ATC, throttle won't be moving, making fine inputs much easier... which is the point I'm trying to make... probably not very successful though... :D

Edited August 9, 2019 by ravenzino

[cofcorpse]

Any ETA on the Approach mode for ATC Cofcorpse?

 

I'm sorry, I can't tell!

[ravenzino]

Yes, it is correct behaviour. Real throttles moves by themselves when ATC is engaged.

Why it is done this way? There could be different reasons. Possibly, to indicate, that ATC is working right now.

While developing modules, we sometimes encounter things that seem to be illogical or impractical. Without full information and years of study of different subjects it is difficult to explain every single decision made by developers of original airplane.

 

Appreciate the thought, I get that.

 

Just thought worth to ask, see if someone can enlighten me a bit.

 

When I stare at that throttle which is nearly in constant move, I keep on asking myself, how difficult it must be to perform some fine input on that mini stick when it almost never stop moving... won't be as easy as on a steady throttle, I guess...

[bbrz]

Without ATC, throttle won't be moving, making fine inputs much easier... which is the point I'm trying to make...

You have apparently never tried to operate any controls in a RW cockpit in turbulence ;)

 

Auto throttle systems are usually doing a rather bad job in turbulence and in most planes it's SOP to disengage the system in severe turbulence.

 

Again, the ATC is a convenience item, nothing more. If it doesn't perform the way it should, or if it disturbs your operation, disengage it.

Edited August 9, 2019 by bbrz

[ravenzino]

You have apparently never tried to operate any controls in a RW cockpit in turbulence ;)

 

Nah, didn't get the chance... won't even bother to pretend... but I'm now very interested in doing so when circumstance allows :) DCS once again sparks my desire of that...

[toutenglisse]

...Any ETA on the Approach mode for ATC ...

 

Can't tell if it's WIP or not, but ATC approach mode works in openbeta since 4 months at least.

 

It works in approach mode if you press ATC when flaps are on Half or Full. (it takes some seconds for ATC to engage, since it cuts throttle, let the plane start stalling, maybe to record min. speed according to weight, then engage and provide auto thrust for constant onspeed flying, after trimming of course)

 

It's described in DCS f/a-18c early access guide page 62. And works like described in guide.

Edited August 9, 2019 by toutenglisse
ATC approach doesn't flash before engaging

[AvroLanc]

Can't tell if it's WIP or not, but ATC approach mode works in openbeta since 4 months at least.

 

It works in approach mode if you press ATC when flaps are on Half or Full. (it takes some seconds for ATC to stop flashing and engage, since it cuts throttle, let the plane start stalling, maybe to record min. speed according to weight, then engage and provide auto thrust for constant onspeed flying, after trimming of course)

 

It's described in DCS f/a-18c early access guide page 62. And works like described in guide.

 

No, it's not implemented yet. At best it's trying to hold speed, at worst it's bugged (as per your description).

[victorlima01]

To the OP: according to at least two different real world F/A18C operators, ATCs were very seldomly used, and never during the tactical phases of flight. I'd imagine if they were to be used during the tactical portion of flight it would be while orbiting a holding fix for CAS missions and the pilot would be operating the TDC to find and designate targets with the Atflir. In that situation the throttles move very little and I don't see how having your left hand resting over them would affect the ATC servos or be a nuisance to operating the TDC.

[ravenzino]

To the OP: according to at least two different real world F/A18C operators, ATCs were very seldomly used, and never during the tactical phases of flight. I'd imagine if they were to be used during the tactical portion of flight it would be while orbiting a holding fix for CAS missions and the pilot would be operating the TDC to find and designate targets with the Atflir. In that situation the throttles move very little and I don't see how having your left hand resting over them would affect the ATC servos or be a nuisance to operating the TDC.

 

Thanks for your direct answer, really appreciate.

 

Like I described above in one of my reply, it is like you are trying to draw a perfect circle using mouse, while someone constantly pulling your mouse pad back and forth in small but constant motion. Although it might not be completely impossible, more than likely it will be much harder to accomplish than it otherwise would be. Now the mouse is the TDC mini stick, the mouse pad is the throttle.

 

When I look at the DCS Hornet throttle, its movement is small though fairly often when ATC is engaged. Of course your hand will be moving with the throttle, but can't be perfectly in sync with it (simple physics as they are not in a "Rigid Connection"), which means the entire mini stick is constantly moving, in tiny scale, relative to your hand/finger. Although this movement could be tiny, say 1mm, the travel distance of the mini stick is also quite small, maybe also 1mm, so it might still significant enough to somehow impact the fine movement of the mini stick, and therefore disturb its operation to some extent. Again, I'm not saying the pilot would therefore not able to get his job done, but such impact seems hard to be entirely ignored...

[David OC]

The only time this would or could be a problem is when lasing a target and you needed to move the tgp very rare im guessing. Another good reason to buddy laze if the target is going to move or use a different weapon. The gps bombs are locked in once you tdc.

[Py]

I get your point.

Without input from an actual pilot with experience on this matter, the logical answer is that if they find it difficult to make fine adjustments, they would disengage ATC.

Or maybe it's standard procedure not to use it in that situation anyway.

[victorlima01]

Thanks for your direct answer, really appreciate.

 

Like I described above in one of my reply, it is like you are trying to draw a perfect circle using mouse, while someone constantly pulling your mouse pad back and forth in small but constant motion. Although it might not be completely impossible, more than likely it will be much harder to accomplish than it otherwise would be. Now the mouse is the TDC mini stick, the mouse pad is the throttle.

 

When I look at the DCS Hornet throttle, its movement is small though fairly often when ATC is engaged. Of course your hand will be moving with the throttle, but can't be perfectly in sync with it (simple physics as they are not in a "Rigid Connection"), which means the entire mini stick is constantly moving, in tiny scale, relative to your hand/finger. Although this movement could be tiny, say 1mm, the travel distance of the mini stick is also quite small, maybe also 1mm, so it might still significant enough to somehow impact the fine movement of the mini stick, and therefore disturb its operation to some extent. Again, I'm not saying the pilot would therefore not able to get his job done, but such impact seems hard to be entirely ignored...

 

You're welcome, although others have provided the same answer before me.

 

Also, the TDC in the real bird is so much better and smoother than what we have (in the warthog at least). For example, I complained to one of these two pilots I mentioned that I wasn't being able to "sweeten up" the target diamond during pop-up bombing runs using auto-delivery. I found the TDC sluggish and very imprecise. Since this pilot had a warthog hotas for DCS he commented that the real TDC is much more precise, and a bit faster to slew around too.

 

So it's not having these little tidbits of information from everyday operations that makes us sometimes assume wrongly.

 

Anyway, you can ask this sort of question straight to the same guys that have been helping me out. Just join Lex's discord. There's a handful of military operators there who're very helpful and patient.

[toutenglisse]

No, it's not implemented yet. At best it's trying to hold speed, at worst it's bugged (as per your description).

 

here a short vid using ATC approach mode.

 

You may find many things wrong the way I do ( ;) ), but at least autothrottle works as described in the guide.