27 minutes ago, Sceadu said:

Seriously?, you think a Force's resultant isnt dependent on the Moment?

Depends on what you're solving for, doesn't it?

Moment = Force x Distance

You're either calculating a force based on local air conditions and geometry and then gathering up all those forces from all those elements to get a cumulative fuselage motion (translation and rotation) or you're going the other way around: distributing moments and calculating a force at each element. Latter doesn't make sense in this case, but that's how the equation works.

For a distributed point model like this one (600+ elements), I do not see a reason to do both. Simultaneously. 

"...to each surface element - local lift, drag and moments coefficients"

Unless it isn't exactly what they've been advertising it is.

Edited November 12, 20223 yr by blingthinger

It turns out the new DC-3 uses CFD. There's a really fascinating video about working with CFD, a bit about AH's timeline to release, and the flight characteristics of the DC-3 both in real world and how it translates to MSFS.

I was worried about it's quality, especially post the Electra debacle, but it might just be my new favourite.

 

10 hours ago, blingthinger said:

Depends on what you're solving for, doesn't it?

Moment = Force x Distance

You're either calculating a force based on local air conditions and geometry and then gathering up all those forces from all those elements to get a cumulative fuselage motion (translation and rotation) or you're going the other way around: distributing moments and calculating a force at each element. Latter doesn't make sense in this case, but that's how the equation works.

For a distributed point model like this one (600+ elements), I do not see a reason to do both. Simultaneously. 

"...to each surface element - local lift, drag and moments coefficients"

Unless it isn't exactly what they've been advertising it is.

So you completely discount the possibility I mentioned earlier that they are using the word "Moment" to mean "Moment arm"?

11 hours ago, Georgleboui said:

It turns out the new DC-3 uses CFD. There's a really fascinating video about working with CFD, a bit about AH's timeline to release, and the flight characteristics of the DC-3 both in real world and how it translates to MSFS.

I was worried about it's quality, especially post the Electra debacle, but it might just be my new favourite.

[[ video of the dc-3 cfd details ]

THANK YOU !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I really need to believe in this CFD "magic" with MFS... I love the seeing so much, and I want to Love the flying too... but that's not going to happen unless I can watch videos like the one you linked. 

Will have to watch the full video, and booked that channel too! He also has other sims analysis - now that called my attention 😉

Edited November 13, 20223 yr by jcomm

6 hours ago, Sceadu said:

So you completely discount the possibility I mentioned earlier that they are using the word "Moment" to mean "Moment arm"?

If that IS what is happening, that means they are ALSO shrinking and growing the airframe when flaps and spoilers are deployed.

The normalization coefficients are based on flaps/spoilers movement. They get multiplied to the forces/moments. If moments are a distance ("moment arm"), that means it's either stretching or shrinking in 3D space.

So...say you're on final approach.  You drop a notch of flaps. The FM immediately grows the wingspan and fuselage a bit because all those "moment arms" (distances to elements) got multiplied by the normalization value corresponding to that particular flap setting. You drop another notch. Fuselage gets even bigger...etc.

I don't like that idea. Do you?

This is partly why I'm claiming Asobo has been lying every time they say the element model solves for forces. It. does. not. I guess marketing requires some stretch of the truth these days...

 

I am also thinking that this is why the CFD model "breaks" or "de-calibrates" the element model. From CFD, you will get forces. You'll end up with pressures on all those elements that are then converted to force because you also have surface area for each of those elements.

They're having to mix apples with oranges. Forces with coefficients. This requires ugly fudge factors.

Take pity on your local 3rd party developer!

Edited November 13, 20223 yr by blingthinger

 

1 hour ago, blingthinger said:

This is partly why I'm claiming Asobo has been lying every time they say the element model solves for forces. It. does. not. I guess marketing requires some stretch of the truth these days...

Your claims so far have all been zero and void.

Assuming the opposite reliably reflected reality closer than any of your claims.

Again and again, after tedious explanations, your convictions were proven wrong.

You keep forgetting, that the essay has gaps. It does not tell exactly how moments are calculated. Fine! We dont have the source code, so accept it and leave it at that. What you do, is looking for gaps in the documentation and fill in the the worst possible (and the weirdest!) assumptions. As I said, you do not read the essay in good faith. In every second line of the essay you seem to find hints that allegedly confirm your foregone conclusion, that Asobo and MSFS is bad. You can be sure, that nothing is shrinking in 3D space. It is clear to everybody, that your interpretations and the resulting conclusions are not only absurd but plain wrong. Sorry, by accusing Asobo to lie but not understanding the details of the flight model you demonstrate a lack of intelectual honesty.

Edited November 13, 20223 yr by mrueedi

2 minutes ago, mrueedi said:

Your claims so far have all been zero and void.

Actually, I'm the only one providing explanations here. You keep quoting sections and then go silent when I respond. We have no reason to believe that you have any idea what you're talking about.

Based on the SDK and your inability to respond properly (or anyone else for that matter), I have no other option than to believe that Asobo have been lying.

Prove me wrong using the SDK.

More than just saying you don't like what I'm saying.

2 minutes ago, blingthinger said:

You keep quoting sections and then go silent when I respond.

Two times I have explained enough that eventually you started posting the exact opposite from your initial, wrong claim.

5 minutes ago, blingthinger said:

I have no other option than to believe that Asobo have been lying.

This is not in good faith. You are fixated on your foregone conclusion and not open minded. There are dozens of other options, which you could embrace including ...

• ... accepting the possibility that the essay has gaps
• ... or they simply do not explain these things detailed enough
• ... or they dont tell us deliberately not more details to protect IP
• ... or they have written the essay just to confuse the competition

4 minutes ago, mrueedi said:

This is not in good faith.

This isn't a matter of faith. It's scientific principles. 

I am suggesting that the essay/SDK contains sufficient information to say that they are coefficients.

You have some questions to respond to here:

 

 

I realize that you dont WANT to respond to them. Maybe you CAN'T respond to them, but they are legitimate issues with your "explanations". Or lack thereof.

 

18 hours ago, blingthinger said:

I realize that you dont WANT to respond to them.

This wrong, I simply don't have enough time to post more.

18 hours ago, blingthinger said:

You have some questions to respond to here:

Explicitely, weight means multiply, yes. Your answer was correct and I thought that was obvious.

The normalization coefficients are not multiplied with "something". It is weird to say that, when the quote of the original text right in the next sentence clearly says that not "something" but lift and drag are multiplied with the coefficients for every surface. An approach in physics, for which the used caption "normalization" is a perfect fit, which to me alone made it entirely clear, what is mulitplied with what.

Edited November 14, 20223 yr by mrueedi

something easy maybe, but am I supposed to see those CFD lines in the Helicopter New York or Soaring Como Lake activities from the marketplace start page? they look nice but distract me too much, can I disable them somehow or is that a CFD showcase and everybody sees these lines?

10 minutes ago, DAD said:

something easy maybe, but am I supposed to see those CFD lines in the Helicopter New York or Soaring Como Lake activities from the marketplace start page? they look nice but distract me too much, can I disable them somehow or is that a CFD showcase and everybody sees these lines?

Yes, you can disable the CFD lines for the helicopters. It's somewhere in assist settings in options. I think for the New York helicopter mission, they tell you exactly where you can disable the CFD lines for the helicopters, on the left sidebar description.

Edited November 14, 20223 yr by abrams_tank

53 minutes ago, abrams_tank said:

Yes, you can disable the CFD lines for the helicopters. It's somewhere in assist settings in options. I think for the New York helicopter mission, they tell you exactly where you can disable the CFD lines for the helicopters, on the left sidebar description.

thx, was disbabled though the lines still showed, so those in the "missions" from the start page seemingly cannot be disabled and always show. starting in NYC "manually" does not show CFD lines, so all good

Probably one of the best opinions I have seen about MFS CFD...

MSFS - Another Aerodynamics Discussion - YouTube

11 hours ago, mrueedi said:

It is weird to say that, when the quote of the original text right in the next sentence clearly says that not "something" but lift and drag are multiplied with the coefficients for every surface.

I know you're struggling to keep up, which is fine. I realize that you're busy.

There are 2 types of coefficient in the SDK: normalization and force/moment. According to this pic from the SDK, the normalization coefficients are multiplied to the force/moment coefficients (upper case Cs everywhere). Not to forces. There are no forces being generated in the airframe solution:

https://docs.flightsimulator.com/html/Samples_And_Tutorials/Primers/Flight_Model_Physics.htm

 

Also, you keep avoiding the issue of solving both moments and forces simultaneously. This is only possible if the elements are NOT solving for forces.