Stby ADI and switch oscillation

[frumpy]

Hi guys,

I just noticed two things on the Navigation-video on youtube.

At about 3:10 the oscillation of a part of the panel that holds a switch can be seen. I feel the oscillation is much too strong, maybe 1/3 of it would be enough for immersion. I assume the switch is screwed on the metal plate, so if the plate is vibrating, the switch should move in the same manner.

 

Also the animation of the standby-ADI seems to be wrong. It's a drum, not a ball like the main ADI. That means the pitch should always move along the vertical axis of the scale, not next to it.

 

[felixx75]

5 hours ago, frumpy said:

I feel the oscillation is much too strong.

You "feel"... That doesn't mean that it isn't correct and can vibrate in the same way. You don't know the exact circumstances and therefore can't really estimate whether it vibrates too strongly or not...

Edited March 17 by felixx75

[draconus]

On 3/17/2024 at 8:56 AM, frumpy said:

Also the animation of the standby-ADI seems to be wrong. It's a drum, not a ball like the main ADI. That means the pitch should always move along the vertical axis of the scale, not next to it.

https://f4.manuals.heatblur.se/cockpit/pilot/flight_director_group.html?highlight=attitude#standby-attitude-indicator

[frumpy]

There seems to be some misunderstanding. I meant the airplane symbol should always move it's center on the vertical line of the horizon drum. On the screenshot the airplane symbol is near to the M, to the right side. The manual that you are pointing at doesn't say anything about this. 

Felixx75: My "feel" is user feedback, not more. If you think it is correct that the plate is moving, but not the switch attached to it, this is your feel. Alternative facts! 

[Hayrake YE-ZB]

It’s not parallax, is it? If they’re modeling that, based on where the pilot’s head is located, then…WOW!

 

[Stackup]

On 3/17/2024 at 2:56 AM, frumpy said:

Also the animation of the standby-ADI seems to be wrong. It's a drum, not a ball like the main ADI. That means the pitch should always move along the vertical axis of the scale, not next to it.

I can gaurantee you the same slop is present in the primary ADI, you just don't see it as it is a 3-axis gyro, not a 2-axis.  Ball or drum doesn't matter, the basic instrument works exactly the same way.  Technically, no ADI should allow the aircraft marking to leave the pitch line as the instrument is not designed to show yaw as they are normally 2-axis gyros.  However, put enough force on it in one direction, for example a high-G right hand turn, and it will show some slop in the yaw axis.  Keep in mind, the primary ADI also functions as a directional gyro like the A-4 Skyhawk's so what yaw there is is hidden by the fact the ball is rotating as you turn.

In both cases, the airplane mark is secured to the instrument housing and therefore, fixed( with some vertical adjustment possible).  The only difference is that you see the primary ADI rotate as it is also showing heading.  The airplane mark stays in the exact same location and mechanical imperfections and inefficiencies as well as gyroscopic forces like precession are what cause what you see.

[doedkoett]

10 hours ago, frumpy said:

There seems to be some misunderstanding. I meant the airplane symbol should always move it's center on the vertical line of the horizon drum. On the screenshot the airplane symbol is near to the M, to the right side. The manual that you are pointing at doesn't say anything about this. 

Felixx75: My "feel" is user feedback, not more. If you think it is correct that the plate is moving, but not the switch attached to it, this is your feel. Alternative facts! 

Usually you can trim the waterline symbol up and down on the SAI, so it isn't necessarily in the middle.  

[frumpy]

On 3/20/2024 at 1:54 AM, Stackup said:

I can gaurantee you the same slop is present in the primary ADI, you just don't see it as it is a 3-axis gyro, not a 2-axis.  Ball or drum doesn't matter, the basic instrument works exactly the same way.  Technically, no ADI should allow the aircraft marking to leave the pitch line as the instrument is not designed to show yaw as they are normally 2-axis gyros.  However, put enough force on it in one direction, for example a high-G right hand turn, and it will show some slop in the yaw axis.  Keep in mind, the primary ADI also functions as a directional gyro like the A-4 Skyhawk's so what yaw there is is hidden by the fact the ball is rotating as you turn.

In both cases, the airplane mark is secured to the instrument housing and therefore, fixed( with some vertical adjustment possible).  The only difference is that you see the primary ADI rotate as it is also showing heading.  The airplane mark stays in the exact same location and mechanical imperfections and inefficiencies as well as gyroscopic forces like precession are what cause what you see.

Thanks for the insight! I have seen quite a few ADIs on pics and did some RW-flying, but never pulled more than 2g so I did not notice any deviation to the side.

[Stackup]

3 hours ago, frumpy said:

Thanks for the insight! I have seen quite a few ADIs on pics and did some RW-flying, but never pulled more than 2g so I did not notice any deviation to the side.

No problem.  Yeah, I'm talking max G turns which can damage stuff unless you vertically adjusted the airplane symbol as seen in the screenshot where it is adjusted above the outer horizon marks causing the deviation.  In normal flight with a centered symbol, it should never leave the pitch ladder.  There's some nuances to be sure with wear of the internal components actually being a factor for the first time in DCS which can lead to things like slop, sticking, or other innacuraccies to any of the mchanical instruments.  It will for sure be interesting to see how it all plays out.