The Physics Model

[Tierborn 188]

1 hour ago, AviatorMan said:

I have seen a number of references in this forum noting that the "physics model" of MSFS2020 is inferior to that of P3Dv5.  Just curious how we know this?

Those references are generally made by those that have chosen to stick with P3Dv5 and do not want to see MSFS succeed as a result.  Those same people do not have enough knowledge of the "physics model" to answer even two question deep in that discussion.

[Ilari Kousa 116]

I think the question is actually really good. That is, what aspects of flight dynamics and performance can even be simulated in a manner relevant to desktop simming, where most setups have neither control loading nor motion feedback?

[Ilari Kousa 116]

..and that said, by way of example, PMDG has advertised their flight models as being within 5% of Boeing data. What exactly does this even mean? Speeds? Fuel burn?

Edited March 28, 2021 by Ilari Kousa

[Chock 17,769]

33 minutes ago, Ilari Kousa said:

..and that said, by way of example, PMDG has advertised their flight models as being within 5% of Boeing data. What exactly does this even mean? Speeds? Fuel burn?

Much is made of this stuff, but to be honest it is PMDG's schtick to say this and is helped by people who insist that SOL emanates from their jacksie. Pretty much every flight sim add-on apart from the truly awful ones, could make similar claims, for example, if Carenado make a PA28 - as they have - which goes at anywhere between around 103 and 115 knots in cruise, then it is within five percent of the real thing's typical cruise speed.

I'd be more surprised if anyone made a half decent add-on which wasn't within five percent of the real thing in most respects, because it would be fairly inept to do so when the gist of making something like that, is typing data into a look up table. After all, if I made a model of a 747-400 and it had a 201 foot wingspan, it'd be wrong by ten feet, but it'd still be within five percent of the real thing's wingspan.

Edited March 28, 2021 by Chock

[Snuffleupagus 327]

As a RW commercial pilot, the main thing I notice with MSFS that definitely isn’t accurate is the up/down twitchiness especially when flaring. It seems to be way too sensitive and doesn’t have enough of a heavy feel like it does in RL. And the liftoff/touchdown reactions are funky. 

[Chock 17,769]

2 minutes ago, pvupilot said:

As a RW commercial pilot, the main thing I notice with MSFS that definitely isn’t accurate is the up/down twitchiness especially when flaring. It seems to be way too sensitive and doesn’t have enough of a heavy feel like it does in RL. And the liftoff/touchdown reactions are funky. 

Most of that is down to the controllers we use and the fact that the sim is to some extent designed to use these too. If we take for example a Spitfire, the real thing's joystick has a pitch throw of about 14 inches or so, but your average joystick for a PC probably isn't even a quarter of that, and so you are hard pressed to replicate subtle control inputs when everything you do is magnified by as much as four times with your controller compared to the real thing.

Attach a three foot stick to your PC joystick and you'd be as smooth as silk on the inputs and it would seem a lot more like the real thing. This is why many are struggling to land that Flying Iron Spitfire super smoothly.

Edited March 28, 2021 by Chock

[tweekz 2,165]

1 hour ago, Chock said:

Beyond this, it's due a considerable update to the flight modeling physics fairly soon which will definitely put this beyond any doubt as to which is superior in terms of modeling flight and air mass reaction, being that it will leave behind the look up chart stuff of the older system in favour of a much more complex and realistic system.

What makes you so confident this is gonna happen "soon"? While I agree that MSFS has huge potential, it seems like they've improved it only very little over the past months. I'm putting my hopes in WT to help them out. But a company that produces world update after world update should be able to review the aerodynamics from ground up at one point!!

[mtaxp 666]

1 hour ago, abrams_tank said:

A poster named noballer08, with a possible background in aerospace engineering over at the official MSFS forums dug into the SDK to determine exactly what the flight model was:

https://forums.flightsimulator.com/t/modern-flight-model/232844/3

My guess is, noballer08 has some type of background in aerospace engineering (at least noballer08 seems to have a good grasp on the math/physics/engineering behind aerodynamics). Anyways, if you think noballer08 did a good analysis of the flight model, this is noballer08's initial impression is of the flight model:

  Quote

  Quote

But, just at first glance, it looks like a really good flight model. Accomplishes the same geometrically-dependent aerodynamic loads that XPlane does with it’s BET/wing-strip method, albeit with more resolution. Definitely the SDK needs much better organization, and the flight model as a whole probably needs additional corrections (such as for compressibility).

https://forums.flightsimulator.com/t/modern-flight-model/232844/11

You really need to get into facts rather thab quoting other and then trying to twist the bottom line.

Long story short; x-plane is used in a pro manner to develop REAL aircrafts, test how they will fly, analyze performance, or in other words it is reliable enough for cessna, the us military, NASA...so if somedbody looking for aerodynamics research, x-plane is the best answer currently.

Edited March 28, 2021 by mtaxp

[Chock 17,769]

Just now, tweekz said:

What makes you so confident this is gonna happen "soon"? 

I'm not, I only said it was due.

[tweekz 2,165]

2 minutes ago, Chock said:

I'm not, I only said it was due.

Sorry, I'm not a native speaker. I saw the due, but in combination with the "fairly soon" I thought you expect something... very soon. 😄

Edited March 28, 2021 by tweekz

[Chock 17,769]

Just now, tweekz said:

Sorry, I'm not a native speaker. I saw the due, but in combination with the "very soon" I thought you expect something... very soon. 😄

It may be, and probably will be, we just have to wait and see, but it is without doubt en-route and would have been in the sim already if it hadn't had a rushed release.

[tweekz 2,165]

3 minutes ago, Chock said:

It may be, and probably will be, we just have to wait and see, but it is without doubt en-route and would have been in the sim already if it hadn't had a rushed release.

I like your positivity. Then they can read through this thread. 😄

https://forums.flightsimulator.com/t/summary-of-missing-items-in-msfs-important-to-realistically-simulate-flight/323758

[Chock 17,769]

4 minutes ago, mtaxp said:

You really need to get into facts rather thab quoting other and then trying to twist the bottom line.

Long story short; x-plane is used in a pro manner to develop REAL aircrafts, test how they will fly, analyze performance, or in other words it is reliable enough for cessna, the us military, NASA...so if somedbody looking for aerodynamics research, x-plane is the best answer currently.

If you seriously think that NASA is firing up Steam and using the same 50 quid copy of XPlane we've all got, to develop their latest spaceship, then I've got a bridge for sale.

[tweekz 2,165]

10 minutes ago, mtaxp said:

You really need to get into facts rather thab quoting other and then trying to twist the bottom line.

I remember someone who claimed we'd hear something about XP12 by X-mas... so, don't go too hard on him. 😉

[mtaxp 666]

8 minutes ago, Chock said:

If you seriously think that NASA is firing up Steam and using the same 50 quid copy of XPlane we've all got, to develop their latest spaceship, then I've got a bridge for sale.

https://github.com/nasa/XPlaneConnect