LUA dynamic friction mod 737NGX

[fakeflyer737 992]

I have the Friction thing in FSUIPC and I have it enabled in the .ini but I don't think it's working. I still need A LOT of break away thrust + continuous thrust to keep the NG moving. 

[WebMaximus 372]

Ok, thanks for the input guys.

So the way I read it at this point in time it's not possible to have this bit simulated in a realistic way in the NGX in P3Dv4.

[Iceman2 110]

8 hours ago, kand said:

Because SIM1.DLL keeps changing every time an update is released, it is time consuming to find the new offsets, I think this is why Pete has omitted it from v5.

I have posted some information here http://www.fsdeveloper.com/forum/threads/friction-coefficient-of-taxi-runways-0-023.440794/

 if anyone wants to play but be warned, all airfiles have their idle thrust and braking setup for the inaccurate fsim friction coefficient so mofifying sim1 means everything will change. 

Hi Kand,

I miss Pete's Lua friction tweak.

So I've been reading a few of your posts and it seems you have a good understanding of what's going on in V4. This is all new to me so I'm learning as I go here.

Since we haven't had an LM update for a while I thought I'd have a go at adjusting the Sim1.dll.

I will download a hex editor tonight and see if I can workout what you guys are doing here.

Is the coefficient of 0.014 still working best for you which I assume is good to use for the lasted download of V4.

I had to flip between a few forums to follow your steps but I gather when I do get the hex editor installed tonight I look for offset 0x148500 and amend to your figure of 0.014.

I understand this may not work with future hot fixes by LM. But in the meantime it seems it's working good for you.

Can you confirm (for the dummies) that this is all I need to do?

Thanks for your work thus far. 🤗

IM

 

ps. What hex editor do you use?

thx

[Iceman2 110]

Tried to amend the dll file but P3D won't run it. Says there's an error.

Btw I used:

8f c2 f5 3c on line 00148500  (SIM1.DLL version 4.0.28.21686)

is this correct?

IM

[kand 205]

6 hours ago, Iceman2 said:

Hi Kand,

I miss Pete's Lua friction tweak.

So I've been reading a few of your posts and it seems you have a good understanding of what's going on in V4. This is all new to me so I'm learning as I go here.

Since we haven't had an LM update for a while I thought I'd have a go at adjusting the Sim1.dll.

I will download a hex editor tonight and see if I can workout what you guys are doing here.

Is the coefficient of 0.014 still working best for you which I assume is good to use for the lasted download of V4.

I had to flip between a few forums to follow your steps but I gather when I do get the hex editor installed tonight I look for offset 0x148500 and amend to your figure of 0.014.

I understand this may not work with future hot fixes by LM. But in the meantime it seems it's working good for you.

Can you confirm (for the dummies) that this is all I need to do?

Thanks for your work thus far. 🤗

IM

 

ps. What hex editor do you use?

thx

Hi, I use Hex editor neo, reason being is it allows you to display the offsets as floating point so you can easily identify where the data resides, there are free editors but Neo for me was worth the price. There are some excel spreadsheets floating around the net which will tell you the order and name of all the surface types but the offsets might be wrong depending on what version of p3d you use.

before you do anything , make a copy of your sim1.dll and do not modify anything at 00148500, that is an old location and the data has since moved due to updates and recompiled code. 

Before anyone goes any further, remember this warning, if you set your wheel rolling friction to 0.014, all of your aircraft will have uncontrollable thrust on the ground at idle and braking will be messed up. If you mess up sim1.dll you will also probably break P3d so make sure you back it up. Finally, if you have modified your friction coefficients, you are on your own when it comes to 3rd party support because no product has been written for this.... 

If you still want to do it, 

Set the data to display as floating point, set the columns to 8 offsets (because for each surface type there are 8 conditions represented by each offset  (apart from when you get to braking which has 4)) and then navigate to x00147700 (if you run p3d4 HF1) as your starting point. If you have done things right you will see 0.050 as the entry, this is the sims rolling wheel friction for concrete.

My 777 airfile is basically rewritten just for my own simulator using NASAs free jet enginesim as the modelling tool. I have also adjusted the sliding frictions and braking for contaminated surfaces, it is so much better, I really wish LM would bite the bullet and apply more mathematically correct coefficients rather than leave it to airfile designers to overcome. I was hoping v4 would be the start but it wasnt to be.  

Bear in mind, every time a new p3d version/hotfix is released you will need to do this all again if you choose to install 

[Iceman2 110]

Awesome Kand,

Thx for taking the time to explain. I will have another go. I have noticed the PMDG ground friction is slightly better on the NG in version 4 than it was in V3. I assume they modified the aircraft somewhat. However the T7 is not right and still needs a lot of break away thrust which is my reasoning for this tweak.

Back to fiddling.

thanks

IM

[ErichB 3,643]

2 hours ago, Iceman2 said:

Awesome Kand,

Thx for taking the time to explain. I will have another go. I have noticed the PMDG ground friction is slightly better on the NG in version 4 than it was in V3. I assume they modified the aircraft somewhat. However the T7 is not right and still needs a lot of break away thrust which is my reasoning for this tweak.

Back to fiddling.

thanks

IM

To be fair, that statement doesn't mean anything in isolation.  'Needs alot of breakaway thrust...'   What's 'alot'?

Fuel load, payload, temperature - aren't specified.  Unless you are a professional T7 driver, our views are subjective as to what is right or not.

[Iceman2 110]

31 minutes ago, ErichB said:

To be fair, that statement doesn't mean anything in isolation.  'Needs alot of breakaway thrust...'   What's 'alot'?

Fuel load, payload, temperature - aren't specified.  Unless you are a professional T7 driver, our views are subjective as to what is right or not.

Hi Erich,

Good answer and you are correct in your response.

I'm certainly no expert in the sim world and don't have a home built cockpit to get the perfect emersion and accurate feel from my plastic controls, but for what its worth I'm basing my opinions from my real world experiences.

I have flown most of the Boeings from the 727 to the 747 and I think Pete's Lua friction tweak in V3 was as close to the real thing as you could get in this sim. The 747-400 for example at max TO weight needed a small amount of breakaway thrust to get her rolling then she'd taxi along nicely at idle thrust doing around 10-15kts. If the airplane was lighter for example just over 1/2 of the max take-off weight she would usually role away very slowly from the ramp without any additional thrust and would need the occasional braking action to slow down to a reasonable taxi speed.

The powerful twin engine T7 most of the time on flat surfaces didn't need any additional breakaway thrust and would roll away gently from the ramp even at high gross weights. (at Max Take-off weight maybe a little nudge of thrust)

Surprisingly with the smaller B737-800 aircraft they usually needed a bit more thrust to get them rolling, even at 3/4 TO weight. We would leave the thrust on a bit until the desired taxi speed was reached and then back to idle thrust.

After landing the aircraft (all the Boeings) would pretty much normally be light weight with only alternate and reserve fuel remaining so when taxiing to the terminal constant braking was needed to stop the aircraft from galloping away. Good braking technique was required to prevent wheel brakes from overheating. 

Back to fiddling 4 me...

Thanks

im

 

[ErichB 3,643]

2 minutes ago, Iceman2 said:

 

I have flown most of the Boeings from the 727 to the 747 and I think Pete's Lua friction tweak in V3 was as close to the real thing as you could get in this sim. The 747-400 for example at max TO weight needed a small amount of breakaway thrust to get her rolling then she'd taxi along nicely at idle thrust doing around 10-15kts. If the airplane was lighter for example just over 1/2 of the max take-off weight she would usually role away very slowly from the ramp without any additional thrust and would need the occasional braking action to slow down to a reasonable taxi speed.

The powerful twin engine T7 most of the time on flat surfaces didn't need any additional breakaway thrust and would roll away gently from the ramp even at high gross weights. (at Max Take-off weight maybe a little nudge of thrust)

Surprisingly with the smaller B737-800 aircraft they usually needed a bit more thrust to get them rolling, even at 3/4 TO weight. We would leave the thrust on a bit until the desired taxi speed was reached and then back to idle thrust.

After landing the aircraft (all the Boeings) would pretty much normally be light weight with only alternate and reserve fuel remaining so when taxiing to the terminal constant braking was needed to stop the aircraft from galloping away. Good braking technique was required to prevent wheel brakes from overheating. 

Back to fiddling 4 me...

Thanks

im

 

I understand where you're coming from.  On that basis I agree as my own assessment of what feels right or not has been made using the same situations.

[Wanthuyr Filho 83]

On 30/08/2017 at 5:06 AM, Iceman2 said:

Awesome Kand,

Thx for taking the time to explain. I will have another go. I have noticed the PMDG ground friction is slightly better on the NG in version 4 than it was in V3. I assume they modified the aircraft somewhat. However the T7 is not right and still needs a lot of break away thrust which is my reasoning for this tweak.

Back to fiddling.

thanks

IM

In reality I noticed some change in the ground dynamics for the 777 PMDG in P3D v4 in comparison to it in v3.x, it seems to me that they managed to improve it, but still it's quite far from perfect. In fact on thing that I noticed a great improvement was the autobrake, now in v4 you may use autobrake 1 and the plane will take a large amount of runway to stop, in contrary to what happened in v3.x, where it stopped so quickly.

[branks737 29]

On 8/30/2017 at 4:42 PM, kand said:

Hi, I use Hex editor neo, reason being is it allows you to display the offsets as floating point so you can easily identify where the data resides, there are free editors but Neo for me was worth the price. There are some excel spreadsheets floating around the net which will tell you the order and name of all the surface types but the offsets might be wrong depending on what version of p3d you use.

before you do anything , make a copy of your sim1.dll and do not modify anything at 00148500, that is an old location and the data has since moved due to updates and recompiled code. 

Before anyone goes any further, remember this warning, if you set your wheel rolling friction to 0.014, all of your aircraft will have uncontrollable thrust on the ground at idle and braking will be messed up. If you mess up sim1.dll you will also probably break P3d so make sure you back it up. Finally, if you have modified your friction coefficients, you are on your own when it comes to 3rd party support because no product has been written for this.... 

If you still want to do it, 

Set the data to display as floating point, set the columns to 8 offsets (because for each surface type there are 8 conditions represented by each offset  (apart from when you get to braking which has 4)) and then navigate to x00147700 (if you run p3d4 HF1) as your starting point. If you have done things right you will see 0.050 as the entry, this is the sims rolling wheel friction for concrete.

My 777 airfile is basically rewritten just for my own simulator using NASAs free jet enginesim as the modelling tool. I have also adjusted the sliding frictions and braking for contaminated surfaces, it is so much better, I really wish LM would bite the bullet and apply more mathematically correct coefficients rather than leave it to airfile designers to overcome. I was hoping v4 would be the start but it wasnt to be.  

Bear in mind, every time a new p3d version/hotfix is released you will need to do this all again if you choose to install 

Thank you sir for your explanation. I was able to follow your steps and read through posts from the fs developer website and work out how to change the friction values in sim1.dll for p3dv4 hotfix 1. What a difference it has made for me in the 737ngx, especially the braking friction, I was able to adjust it so it doesn't feel like your landing in sand anymore. 

I located the braking friction starting from offset 001489c0 after setting the columns to 4. Also there is a free basic version of hex editor neo which has enough functions do accomplish the above. 

[Iceman2 110]

2 hours ago, branks737 said:

Thank you sir for your explanation. I was able to follow your steps and read through posts from the fs developer website and work out how to change the friction values in sim1.dll for p3dv4 hotfix 1. What a difference it has made for me in the 737ngx, especially the braking friction, I was able to adjust it so it doesn't feel like your landing in sand anymore. 

I located the braking friction starting from offset 001489c0 after setting the columns to 4. Also there is a free basic version of hex editor neo which has enough functions do accomplish the above. 

Hi Branks737

What ground friction setting did you use? With the help from Kand I too have my DLL file edited, but I may have to re-adjust this value since PMDG have been modifying their on products lately and the NGX is a bit happy to gallop away from the stable at MAX takeoff weight. Unfortunately the T7 & 74 are about right for my current Sim.DLL setting. 

I may have to have two files available and change them depending on which wagon I choose to fly on the day.

IM

[branks737 29]

1 hour ago, Iceman2 said:

Hi Branks737

What ground friction setting did you use? With the help from Kand I too have my DLL file edited, but I may have to re-adjust this value since PMDG have been modifying their on products lately and the NGX is a bit happy to gallop away from the stable at MAX takeoff weight. Unfortunately the T7 & 74 are about right for my current Sim.DLL setting. 

I may have to have two files available and change them depending on which wagon I choose to fly on the day.

IM

Each will have there own preference. I for one do not care much for breakaway thrust as I would prefer more friction to counter the plane from feeling like its on an icy lake when moderate or stronger crosswinds are present. These are my settings for the ngx; rolling friction=0.70 and sliding friction I reduced to 0.34. Braking friction I reduced quite a bit to 0.22

These are the default values; rolling friction=0.50, sliding friction=0.64 and braking=0.70

Now I only changed these values for concrete, asphalt, bituminus and tarmac. I am still experimenting with the values.

 

[kand 205]

4 hours ago, branks737 said:

Each will have there own preference. I for one do not care much for breakaway thrust as I would prefer more friction to counter the plane from feeling like its on an icy lake when moderate or stronger crosswinds are present. These are my settings for the ngx; rolling friction=0.70 and sliding friction I reduced to 0.34. Braking friction I reduced quite a bit to 0.22

These are the default values; rolling friction=0.50, sliding friction=0.64 and braking=0.70

Now I only changed these values for concrete, asphalt, bituminus and tarmac. I am still experimenting with the values.

 

Reducing your sliding friction coefficient will make the plane feel like its on ice! you need to increase the value to give you more grip. I use 1.0 throughout for my setup 

[Iceman2 110]

Thanks Branks737

Appreciate your post.

IM