Well than why is this on the PMDG 737NGX product page?

Raise the wing spoilers and watch as the virtual hydraulic fluid moves through the system and causes the pressure and quantity to change in real time

 

What the esteemed gentlemen (and ladies?) of PMDG are trying to tell us mere mortals is that, instead of doing things the way any garden variety flight sim developer would do and simply changing output screen parameters programmatically as a direct result of user control input (i.e. "if speed brake lever = up then decrease hydraulic quantity by 10%"), they actually simulate the flow of virtual hydraulic fluid through the lines, and then derive the pressures and quantities to be displayed from that. In other words, they are just showing off the size of their... virtual hydraulic lines to their awestruck customers and the world at large. Makes sense? ^_^

 

Why would they be refering to the eicas at all!? They *clearly* hint to *watch* as it moves through the *system*. Not watch it on the *screen*

 

The key phrase is "watch as the virtual hydraulic fluid moves through the system and causes the pressure and quantity to change in real time".

 

The ONLY place you can monitor either the hydraulic pressure or quantity changing is on the EICAS display... seems obvious that is what is being referred to.

 

Besides, even if it were somehow possible to implement transparent hydraulic lines, you would NOT see the fluid actually moving, even if it was flowing at a high rate of speed. The only way you could see it move would be if there were air bubbles or some other contaminant in the fluid.

There's a difference between "Watch as the fluid moves through the system." and "Watch the fluid moving through the system.".

The first one can point to the lower centre screen, the second one is a lot harder to interpret that way. I think PMDG made a right choice concerning grammar and words.

Why would they be refering to the eicas at all!? They *clearly* hint to *watch* as it moves through the *system*. Not watch it on the *screen*

 

I'm sorry but it just dosen't make sense to me.

 

Maybe tabs can come prove me completely wrong.

 

I remember this topic: http://forum.avsim.net/topic/376268-just-wanted-to-point-out-how-realistic-the-ngx-is/ Here he means that you can see the hydraulic fluid move from one side to the other. Something that no other add-on has done before.

I think that this is more or less what PMDG meant, that you have an accurately simulated hydraulic system where you can "see" the fluid move around instead of just being some fix numbers written in the software...

 

Regards,

Manfred

If I remember correctly, quite a bit ago before the NGX service packs, I used to look at the wing with the spoilers up, and extend the flaps, and I could see the hydralic fluid flow through the pipes.

 

I hear there are a variety of substances that can cause this effect.

 

Hook

Why would they be refering to the eicas at all!? They *clearly* hint to *watch* as it moves through the *system*. Not watch it on the *screen*

 

I'm sorry but it just dosen't make sense to me.

 

Maybe tabs can come prove me completely wrong.

 

You're wrong

 

I wrote the sentence in question in the NGX's product description and I was in fact referring to looking at the lower DU status page to see the hydraulic system changes. (This was shown on a video around the time of release, that's where it came from) Hydraulic lines are not visible (nor are they transparent) on airplanes. Even if you could see them transparently, you wouldn't visibly see fluid moving because what changes is pressure inside the system - it isn't the line going from empty to full of fluid or something. There's always some amount of fluid in there, the relative pressures just change when you want to actuate a certain control surface. As someone pointed out, the green rod when the spoilers are up is an actuation jackscrew, not a hydraulic line. (the hydraulics are ultimately what's turning that screw, but that mechanism is deep inside the aircraft and not visible)

 

The NGX uses some very complex math to actually simulate the dynamic flow of virtual fluids through the airplane - fuel, hydraulics, pneumatics (air is treated as a "fluid" in the language of physics) etc - these aren't just simple on/off switches in the systems like some other addons you may have seen. The true underlying physical reality of the system is what's really being simulated mathematically here. When you have a failure in one of these systems or something like that in the NGX, the actual failure happens not because some arbitrary piece of code says "failure here" but because something actually cuts off or leaks out the virtual fluid in question and the failure happens as a result of *that* physical event. (again, this is mathematically speaking - you aren't going to visibly see fluid leaking - it could be happening deep in the belly or wing or part of the engine etc)

 

This is the kind of thing that frustrates us at times as developers because it can be hard to get the average simmer to understand the level of simulation we go to when they can't visually see it. You can't in fact "see" most of these things that are happening mathematically beneath the surface, so to some people it can look like we just did the "on/off" switch way of simulating things. That's not at all what it is - what we do very closely approximates the way actual full flight level D simulators work.

 

This stuff will be a lot easier to see happening on the 777 because you have the lower EICAS synoptics that show you the current state of the each system in far more detail than the NGX displays do.

Hydraulic lines are not visible (nor are they transparent) on airplanes. Even if you could see them transparently, you wouldn't visibly see fluid moving because what changes is pressure inside the system - it isn't the line going from empty to full of fluid or something. There's always some amount of fluid in there, the relative pressures just change when you want to actuate a certain control surface.

Thanks for the thorough explanation! It is certainly logical from a physical (i.e., involving physics) perspective.

Skydrol fluids are given a purple dye to make it easy to distinguish them from other fluids. But the dye does not usually last as long as the fluid does. The color may change from purple to gray or yellow or green.

 

 

http://www.skydrol.com/pages/faqs.asp

You're wrong

 

I wrote the sentence in question in the NGX's product description and I was in fact referring to looking at the lower DU status page to see the hydraulic system changes. (This was shown on a video around the time of release, that's where it came from) Hydraulic lines are not visible (nor are they transparent) on airplanes. Even if you could see them transparently, you wouldn't visibly see fluid moving because what changes is pressure inside the system - it isn't the line going from empty to full of fluid or something. There's always some amount of fluid in there, the relative pressures just change when you want to actuate a certain control surface. As someone pointed out, the green rod when the spoilers are up is an actuation jackscrew, not a hydraulic line. (the hydraulics are ultimately what's turning that screw, but that mechanism is deep inside the aircraft and not visible)

 

The NGX uses some very complex math to actually simulate the dynamic flow of virtual fluids through the airplane - fuel, hydraulics, pneumatics (air is treated as a "fluid" in the language of physics) etc - these aren't just simple on/off switches in the systems like some other addons you may have seen. The true underlying physical reality of the system is what's really being simulated mathematically here. When you have a failure in one of these systems or something like that in the NGX, the actual failure happens not because some arbitrary piece of code says "failure here" but because something actually cuts off or leaks out the virtual fluid in question and the failure happens as a result of *that* physical event. (again, this is mathematically speaking - you aren't going to visibly see fluid leaking - it could be happening deep in the belly or wing or part of the engine etc)

 

This is the kind of thing that frustrates us at times as developers because it can be hard to get the average simmer to understand the level of simulation we go to when they can't visually see it. You can't in fact "see" most of these things that are happening mathematically beneath the surface, so to some people it can look like we just did the "on/off" switch way of simulating things. That's not at all what it is - what we do very closely approximates the way actual full flight level D simulators work.

 

This stuff will be a lot easier to see happening on the 777 because you have the lower EICAS synoptics that show you the current state of the each system in far more detail than the NGX displays do.

 

Lol, thank you. I understand now.

 

However it seems lots of people like to see me 'proven wrong'. Haha.

Skydrol fluids are given a purple dye to make it easy to distinguish them from other fluids. But the dye does not usually last as long as the fluid does. The color may change from purple to gray or yellow or green.

 

I take the point that skydrol will change colour but after 35 years working on the line and in the hanger I've never seen it turn yellow or green but have seen it range from very purple ( new) to almost black (Hyd servicing dump)

also before someone asks about red hyd fluid thats dtd585 and is used now mainly on u/c leg servicing although some older generation a/c used it as the hyd fluid HS748 for example

However it seems lots of people like to see me 'proven wrong'. Haha.

 

I thought that was me? Join the club :wink:

 

I take the point that skydrol will change colour but after 35 years working on the line and in the hanger I've never seen it turn yellow or green but have seen it range from very purple ( new) to almost black (Hyd servicing dump)

also before someone asks about red hyd fluid thats dtd585 and is used now mainly on u/c leg servicing although some older generation a/c used it as the hyd fluid HS748 for example

 

Even some recent aircraft... Dassault uses MIL-H-5606 / DTD585 exclusively in their Falcon line... even brand new ones. They never adopted Skydrol, despite its low flammability rating, because of its solvent effect on rubber, plastics and (especially) painted surfaces. As a fellow wrench-turner, I'm sure you'll agree that Skydrol is an unpleasant substance to work with!

I thought that was me? Join the club :wink:

 

B)

Even some recent aircraft... Dassault uses MIL-H-5606 / DTD585 exclusively in their Falcon line... even brand new ones. They never adopted Skydrol, despite its low flammability rating, because of its solvent effect on rubber, plastics and (especially) painted surfaces. As a fellow wrench-turner, I'm sure you'll agree that Skydrol is an unpleasant substance to work with!

without doubt especially after the first time you get a drop in your eye :Cry: will never forget that unfortunate day.

As you say skydrol best paint stripper out there lol