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Inherent flaw of FSX to give too much ground friction?

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Guest Raul_Hernandez

Brilliant work by Pete here - as always working hard to push the bar of realism and fun in our hobby!

 

Keep up the excellent work Pete.

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Does FSUIPC do some patching of VISUALFX.dll as well ?

 

It hooks specific calls into that DLL and into SIM1 in order to effect the wind smoothing and direct ambient wind control. It has done since way back. There are also other hooks placed in SIM1 for this. ("Hooks" are where the code sequence is diverted through other code (in FSUIPC1) and back again).

 

There were many many more hooks and patches before SimConnect made a lot of stuff more sanitory. ;-)

 

Pete

 

The link for FSUIPC4859j.zip (latest version: j ) is OK at http://fs-mp.com/sim1/

 

Best not to have links to specific versions, only to the right thread in the SubForum. Version 4.859k will replace 4.859j very soon ...

 

You'll find everything also at the Peter Dowson support forums here :

http://forum.simflig...pdated-modules/

 

Better, but still best to go one level up, to Download Links so you find the updated Lua plug-ins package too. It is that which contains the Frictions.lua and the documentation listing the names of all the surfaces etc.

 

Pete


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Best not to have links to specific versions, only to the right thread in the SubForum. Version 4.859k will replace 4.859j very soon ...

 

Good news. Thanks Pete !

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Better, but still best to go one level up, to Download Links so you find the updated Lua plug-ins package too. It is that which contains the Frictions.lua and the documentation listing the names of all the surfaces etc

That's Dated 05 May 2011?

 

I've just done a very simple test.

MS 172 full throttle to a point on the runway and then F1 to see how far it rolls, no breaks.

 

With the "fix" the 172 rolls about x2 the distance.

 

But does these mean the NGX auto breaks are going to take x2 longer to bring the aircraft to 40knots?


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That's Dated 05 May 2011?

 

What is? The Lua plugins ZIP file, posted yesterday? Have you looked at it?It is dated 5th December 2012. It even says so in the ZIP name. Don't you see the Frictions things listed in the changes list just below?

 

Maybe you are confused because I don't post a complete new announcement each time I need only add or amend one line in an existing one. The stupid Forum software doesn't update the date, it only keeps the origination date. I'm surprised you've not noticed this before. The only way around it would be to delete the existing thread and post a completely new one each time, and really I have better things to do, and it's never been a problem in any case.

 

Pete


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Pete Sorry I did not DL it because I thought the post looked old and could not see a EDIT DATE XXXXX.


David Murden  MSFS   Fenix A320  PMDG 737 • MG Honda Jet • 414 / TDS 750Xi •  FS-ATC Chatter • FlyingIron Spitfire & ME109G • MG Honda Jet 

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DCS  A10c II  F-16c  F/A-18c • F-14 • (Others in hanger) • Supercarrier  Terrains = • Nevada NTTR  Persian Gulf  Syria • Marianas • 

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With respect to crosswind landings, not all airliners should crab the maingear at touchdown. It is all to do with the relative sideloading that the undercarriage can withstand. Only the really big boys can play at crabbing the mains on touchdown and even then, you will often see the decrab occur before touchdown to reduce the sideways loading on the gear. Not a good idea to crab a 737/A320 or smaller right onto the runway. A small degree of crab may be necessary in particularly heavy wind conditions, as illiustrated by the video below...

 

There are some great YT videos illustrating this, particularly during Storm Andrea on Germany (look for a ca. 10 minute video of landings at Düsseldorf Airport...)

 

A

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I've replaced 4.859j with 4.859k which computes the correct table address in process memory in a different way. I'm hoping this fixes the problem reported earlier by Vic Baron. It also now logs the address used and the success or otherwise of the friction setup.

 

Regards

Pete


Win10: 22H2 19045.2728
CPU: 9900KS at 5.5GHz
Memory: 32Gb at 3800 MHz.
GPU:  RTX 24Gb Titan
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True, we certainly don't want to land our GA Airplanes with a Crab Angle. But at touchdown with default friction the plane will travel sideways with the wind, almost impossible to hold the centerline with rudder, so this friction makes things more controllable


Alexis Mefano

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With respect to crosswind landings, not all airliners should crab the maingear at touchdown. It is all to do with the relative sideloading that the undercarriage can withstand. Only the really big boys can play at crabbing the mains on touchdown and even then, you will often see the decrab occur before touchdown to reduce the sideways loading on the gear. Not a good idea to crab a 737/A320 or smaller right onto the runway. A small degree of crab may be necessary in particularly heavy wind conditions, as illiustrated by the video below...

 

There are some great YT videos illustrating this, particularly during Storm Andrea on Germany (look for a ca. 10 minute video of landings at Düsseldorf Airport...)

 

A

 

I guess in no plane its good to land and skid the tires over the asphalt due to crossind.

As soon as the rubber hits the ground, on dry surface, you have grip. If the pilot keeps on crabbing then you slide, and it will be a coslty operation to replace the

tires.

 

Thats why all planes at landing should right just before touchdown decrab and center with the runway centerline.

 

On a wet or icy/snow runway you can keep the crab untill touchdown and straight with rudder then to the centerline.

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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.

Just to put some objective numbers on this, I tested the PMDG NGX with and without the mod at max TOW. I used maximum derated thrust for the conditions (EGSS runway 04, ISA, no wind) according to TOPCAT using data for the FS9 PMDG 737NG. This calculated an assumed temp of 38 deg C for Flaps 1.

 

At max TOW the 737-800 (no winglets) hit Vr at 41 seconds with the mod and 46 seconds without it. It travelled 8 centreline lights further down the runway without the mod, so about 400 ft longer.

 

Using the same thrust setting, but with no payload and 1/3 fuel, time to Vr was 21 seconds with the mod (22 without) and the extra distance without the mod was 1 light (50 ft). At this light weight without the mod the NGX didn't move with idle thrust, but with the mod it began rolling when the brakes were released. I'm not a 737 pilot, but at such a light weight I'd be surprised if the aircraft didn't roll at idle thrust.

 

I then tried a rejected takeoff at MTOW to see how close to the runway end the NGX got (TOPCAT gave the margin as 54 ft).

 

Without the mod the NGX accelerated to V1 and stopped in 60 seconds, using RTO autobraking only after chopping the throttles. No speedbrake, no reverse thrust. By counting lights it was approximately 2,220 ft from the runway end.

 

With the mod, the time to stop was 58 seconds and the aircraft stopped 2,350 ft from the runway end. So not a huge difference overall (2 seconds and 130 ft).

 

So with the mod the takeoff time and distance is reduced at heavy weights, but the stopping time is increased to almost balance that out.

 

Note: I'm using FSX + Accel and introduced the mod by using Pete Dowson's latest development mod to FSUIPC (unlicensed version).

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We need to test it with some heavy weight planes, like the MD11 taking off from Europe to the US continent. I bet this mod will make a LOT of difference in this scenario.


Alexis Mefano

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We already eshtablish that Alec, there IS a difference.

 

Unless you or someone else wants to change the NGX airfile you eiher take or leave it.

It will be different on a lot of planes, but the low thrust planes I think will suffer less, and might be neglectable.

We just provided the environment, its up to the community to adjust for individual planes where needed.

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We already eshtablish that Alec, there IS a difference.

 

Unless you or someone else wants to change the NGX airfile you eiher take or leave it.

It will be different on a lot of planes, but the low thrust planes I think will suffer less, and might be neglectable.

We just provided the environment, its up to the community to adjust for individual planes where needed.

 

Amen to that.. very well put, take it or leave it. the functionality has been made available via FSUIP4, Lua Friction file to make/adjust your own for those perfectionists out there.

 

I think it never was a case from day one to have the ultimate set that will address each and every plane and the understanding from day one (as I understand that) was that this will be a generic enhancement patch, and also will NOT be made for just ONE specific plane eg PMDG 737. if you want it for a specific plane, use the tools that has been made available and create your own. Easy as that.!!

 

So far the patched version work perfectly for me on the planes I generally fly and I will accept a compromise on the odd plane, but believe me I am Happy camper. generally my flightsim experience is better and that is all what is important for me.

 

Brilliant work Johann and Pete. My hat off to you..!

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