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Inherent flaw of FSX to give too much ground friction?

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Guest FSMP

My point is, is there a scalar that will allow one to modify friction in the lateral axis?

 

 

I think that there is a lack of modeling lateral axis friction in FSX (p3D) , so no scalars to adjust for this.

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Whowww! :blink:

 

When I started this thread last Friday, I didn't think it would become such a hot topic. Or at least a couple of talented individuals (Johan & Pete) made it so! Just came back from work and was amazed to see 75 replies and 2455 views! I will try the "fix" when I get a chance.

 

On Johan's website, there is "fsx.tire.friction.coeff.update-patch.exe", in addition to the sim1.dll in "sim1_SP2_121204". Are we supposed to replace the sim1.dll and apply the patch, or just replace the sim1.dll (or simply apply the pacth alone)?

 

Thanks again to Johan and Pete for all their work and talent.

 

Pierre

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Well, the bad news is that I just tested PMDG 737NGX and this new Sim1.dll has changed the Takeoff Run a lot, the aircraft without the fix took more runway to get to the same speed, and stopped much quicker than the one with the Sim1.dll .

 

This means Addon Developers would have to test their birds using this fix to give us realistic values, if not, our takeoff and landing distances will be completely wrong for all addons. But nevertheless, the feeling is much better with this fix, landing with a crosswind now is much more challenging.


Alexis Mefano

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Well, the bad news is that I just tested PMDG 737NGX and this new Sim1.dll has changed the Takeoff Run a lot, the aircraft without the fix took more runway to get to the same speed, and stopped much quicker than the one with the Sim1.dll .

 

I got a nickel says they modified that file.

 

Hook


Larry Hookins

 

Oh! I have slipped the surly bonds of Earth
And danced the skies on laughter-silvered wings;

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No, it is perfect.

 

I fly C208 for real in Myanmar and I can tell you that FSX is realistic, at least on that aircraft type.

 

Maybe other aircraft types (larger jets) are more frictional and flarty.

Do you mean Original FSX is perfect for the C208 or this experimental patched version?


SkipperMac

 

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Guest FSMP

Whowww! :blink:

 

When I started this thread last Friday, I didn't think it would become such a hot topic. Or at least a couple of talented individuals (Johan & Pete) made it so! Just came back from work and was amazed to see 75 replies and 2455 views! I will try the "fix" when I get a chance.

 

On Johan's website, there is "fsx.tire.friction.coeff.update-patch.exe", in addition to the sim1.dll in "sim1_SP2_121204". Are we supposed to replace the sim1.dll and apply the patch, or just replace the sim1.dll (or simply apply the pacth alone)?

 

Thanks again to Johan and Pete for all their work and talent.

 

Pierre

 

Either, apply the PATCH to your existing sim1.dll, OR replace your Sim1.dll with the appropriate FSX Version , "already patched" file.

 

Better still, it looks like the latest version of FSUIPC, will effectively patch FSX automatically.

 

I got a nickel says they modified that file.

 

Hook

 

I really don't think that PMDG would have their "aircraft install" MODIFY any of the simulator's native dlls.

 

There would be potentially disastrous consequences if they did !!!

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I think that there is a lack of modeling lateral axis friction in FSX (p3D) , so no scalars to adjust for this.

 

Of course there is, and the sliding friction for that is raised to remove the spaghetti effects. That was the whole idea to begin with. Rolling friction is changed as bonus.

 

Well, the bad news is that I just tested PMDG 737NGX and this new Sim1.dll has changed the Takeoff Run a lot, the aircraft without the fix took more runway to get to the same speed, and stopped much quicker than the one with the Sim1.dll .

 

This means Addon Developers would have to test their birds using this fix to give us realistic values, if not, our takeoff and landing distances will be completely wrong for all addons. But nevertheless, the feeling is much better with this fix, landing with a crosswind now is much more challenging.

 

Might be. Stopping distance you can adjust with the brake action in the cfg yourself.

Taxi speed on idle is hidden in 1506 in the airfile, rather easily to adjust, but will explain this when at home with a picture or two.

 

Of course addon developpers cannot make a version with this sim1.dll in mind.

We have to adjust our favorite aircraft ourselves, what is not too difficult to do.

With some team effort you can work together to get a nice value to enter in.

 

I just remembered I have to try out turf. I always found turf to require way too low a power setting to start rolling.

 

Great job!!

 

Sorry, didnt expect anyone to try out turf, so that value I didnt change. Will look into it this evening.

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Guest FSMP

The technology to "PATCH" sim1.dll is very exciting, and does seem to provide potential significant improvements to the behavior of different aircraft, BUT, there would appear to be one big catch.

 

Up to now, developer's have developed their aircraft to behave, as best they can, with the original Microsoft sim1.dll friction parameters.

 

If users now change sim1,dll's parameters, it would seem to have unpredictable effects on how the developer designed their aircraft. Things could easily get very distorted and unpredictable.

 

Here is one suggestion, that might help, and that Peter Dowson (FSUIPC) might consider.

 

An new "aircraft custom paramater configuration file", that developers could optionally provide with their aircraft ( just like they do, say the aircraft.cfg file), that includes a sim1.dll table, tailored for that aircraft.

 

If say, FSUIPC could read that table, if it was present for that aircraft, and load that as the sim1.dll PATCH info, then there would be a way for developers, and users, to control these( and other) parameters, on an aircraft by aircraft basis.

 

If FSUIPC is the way to do this, then this optional file, would become one formatted to meet the requirements to work with FSUIPC, and would become just another FLIGHT SIM standard "configuration file" accompanying an aircraft.

 

This concept could also be extended, to patching other dll's parameters, as the need arises.

 

If every plane, either had their own OFFICIAL "parameter configuration file" as supplied by the developer, (and potentially modifiable by the user), or defaulted to a STANDARD "parameter configuration file" (or the original dll's parameters), then the whole process would be a lot more controllable and manageable.

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FSMP

 

I like your way of reasoning and I think it is an awesome suggestion..! Can even be part of the current FSUIP4.ini file where data is in any way stored per plane if selected, or it can be a generic value for ALL planes. Lets see what Pete say about the suggestion.

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Guest FSMP

FSMP

 

I like your way of reasoning and I think it is an awesome suggestion..! Can even be part of the current FSUIP4.ini file where data is in any way stored per plane if selected, or it can be a generic value for ALL planes. Lets see what Pete say about the suggestion.

 

My suggestion was to make the individual, customized AIRCRFT configuation file part the aircraft file set, (ideally supplied by the developer for his aircarft), and have FSUIPC be the mechanism to read that file, if it was present in the aircraft folder, and use it to dynamically PATCH sim1.dll in memory.

 

This way, any changes to the sim1.dll, is directly associated with each aircraft, and is part of that aircraft file set.

 

When get a new Aircraft, it would either come with its own sim1.dll Parameter Config file, or else the FSUIPC would use, either the Microsoft Standard sim1.dll or a generic Modified version.

 

Old aircraft would either use The Standard or Generic parameter set, or it would be possible to generate a New Custom Aircraft parameter file, for that specific aircraft, by putting it into the aircraft folder. These custom aircraft files would be created, either by the Original Aircraft Developer, as an update, another developer, or failing that, by the Flightless Community.

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(1) Does FSUIPC modify the sim1.dll file itself, or does it patch the memory where sim1.dll resides, when loaded into FSX.

 

The run-time copy, in memory. Nothing I produce ever modifies other products files on disk!

 

(2) If one is using FSUIPC to effect these changes, should one ensure that their sim1.dll is the original one that got installed by FSX (and not a patched version).

 

It would be best, otherwise how can you revert to default if you want to compare?

 

Regards

Pete

 

I think that there is a lack of modeling lateral axis friction in FSX (p3D) , so no scalars to adjust for this.

 

No, the lateral friction also has scalars. The 8 entries for each surface type are divided into 4 for longitudinal friction and 4 for lateral friction, the 4 in each being for different surface conditions.

 

Pete

 

This means Addon Developers would have to test their birds using this fix to give us realistic values, if not, our takeoff and landing distances will be completely wrong for all addons. But nevertheless, the feeling is much better with this fix, landing with a crosswind now is much more challenging.

 

Since the facilitiy in FSUIPC for mapping the values to offsets allows them to be changed dynamically, on the fly as it were, each aircraft model could have a Lua plug-in auto-running to set values suited to it specifically, as part of its Profile.

 

Pete

 

Up to now, developer's have developed their aircraft to behave, as best they can, with the original Microsoft sim1.dll friction parameters.

...

If say, FSUIPC could read that table, if it was present for that aircraft, and load that as the sim1.dll PATCH info, then there would be a way for developers, and users, to control these( and other) parameters, on an aircraft by aircraft basis.

 

For now I'd prefer this to be implemented the way I suggested, i.e. by using Lua plug-ins, auto run (in the relevant [Auto.<profilename>] section, to actually patch the values as needed. Maybe, when there's more knowledge of what values might need changing for different aircraft models and makes I can think about using specific data files instead, or as well, but until we know enough it is far more flexible using what I have already provided.

 

Regards

Pete


Win10: 22H2 19045.2728
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Guest FSMP

No, the lateral friction also has scalars. The 8 entries for each surface type are divided into 4 for longitudinal friction and 4 for lateral friction, the 4 in each being for different surface conditions.

 

 

Regards

Pete

 

Thanks for the correction.

 

I am still a little confused.

 

FSX refers to Breaking Friction and Sliding Friction.

 

Are these FSX's terms for Kinetic and Static friction, or are Breaking & Sliding Friction something different ?

 

 

 

Ref:

There are two forms of friction, kinetic and static. If you try to slide two objects past each other, a small amount of force will result in no motion. The force of friction is greater than the applied force. This is static friction.

 

If you apply a little more force, the object "breaks free" and slides, although you still need to apply force to keep the object sliding. This is kinetic friction.

 

You do not need to apply quite as much force to keep the object sliding as you needed to originally break free of static friction.

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FSX refers to Breaking Friction and Sliding Friction.

 

Where?

 

You aren't reading "braking" as "breaking" are you? The tables Johan and I refer to is entitled

 

"Sim1.dll Rolling, Sliding and Braking Friction Coefficients".

 

See the Excel file linked to much earlier in this thread.

 

Pete


Win10: 22H2 19045.2728
CPU: 9900KS at 5.5GHz
Memory: 32Gb at 3800 MHz.
GPU:  RTX 24Gb Titan
2 x 2160p projectors at 25Hz onto 200 FOV curved screen

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Rolling is how much resistance the tires got from forward friction, the less the better. 0.25 is used as a average for aircraft (real world). Was 0.55.

Sliding is lateral, slipping, or skidding as you may call id. A friction, usually rubber on concrete is 1.0 as a standard value.

 

Braking is just a value, like concrete=0.7. What is 0.7 ? I dont know. But it gave a real decelleration when rolling resistance(also a sort of braking) was 0.55.

I upped it to 0.8 and 0.9 to cope with this been lowered to 0.25.

 

Capish ?

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Guest FSMP

Rolling is how much resistance the tires got from forward friction, the less the better. 0.25 is used as a average for aircraft (real world). Was 0.55.

Sliding is lateral, slipping, or skidding as you may call id. A friction, usually rubber on concrete is 1.0 as a standard value.

 

Braking is just a value, like concrete=0.7. What is 0.7 ? I dont know. But it gave a real decelleration when rolling resistance(also a sort of braking) was 0.55.

I upped it to 0.8 and 0.9 to cope with this been lowered to 0.25.

 

Capish ?

 

Yes, Capish -- Thanks, but this leads to another question.

 

 

Is there any modeling of tyres that have grip on the surface, then loosing grip and skidding, and the associated modeling of "automatic breaking systems" with anti-skid ?

Planes with Anti-skid options -- is this really simulated, or just approximated somehow ?

 

Maybe, if LUNA can patch these parameters in Real time, Luna could be used to help simulate more complex braking systems ?

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