Sim1.DLL ground friction mod

Does anyone have this? I've used it in the past but I can't find it now. I wanted to give it another whirl.

I don't have the modified DLL file, but here is a previous post showing how the edits work:

 

Changing Friction values in the FS2004 sim1.dll

 

Simon

External

Since: Oct 26, 2006

Posts: 4

 

(Msg. 11) Posted: Fri Oct 27, 2006 7:08 am

Post subject: Re: Changing Ground Friction Values...Can Someone Translate German? [Login to view extended thread Info.]

Archived from groups: per prev. post (more info?)

Hi,

 

In my previous post details this fix I got the decoded values in the

example tables wrong. This should be correct.

 

Below is a post I did to another forum. It tries to explain about

editing SIM1.dll

 

I hope it helps.

 

I think I have a solution.

 

The behavior on rollout seems to be caused by a lack of friction for

sideways movement, (skid friction).

 

Note! I have only done limited testing on this. It seems to make cross

wind landing rollout better, I think it helps with the tendency to

rotate left or right on engine start in some big twins, not sure about

this but it seems better. I may try increase the friction later. It may

also fix the tendency to weathervane on high speed taxi in strong

winds.

 

Based on some work I found on a German Web sit, See my post on Oct 23rd

at 12:30, I have found the following fix.

 

First you will need a HEX editor, I use XVI32, this is freeware

available at

http://www.chmaas.handshake.de/delphi/freeware/xvi32/xvi32.htm

 

The fix requires you to edit SIM1.DLL in “Flight Simulator 9/Modules”

directory.

 

Make a copy of SIM1.DLL and put it in some other directory. If you

leave it in the same directory FS9 won’t load.

 

Open SIM1.DLL with XVI32. Scroll down to the line which has 48CBA in

the left hand column.

 

The values in that line are shown below. The interesting area is in

red. I have shown the entries for Wheels on Concrete and Asphalt. There

are others for grass etc.

So, Change E17AE43F to AE47F13F. This does concrete.

 

For Asphalt go to the line 48CBA and repeat the above.

 

Save and exit XVI32

 

 

Wheels, Concrete

Original Microsoft Value

48CBA 00009999A93FC78424880000007B14AE47C784248C000000E17AE43FC784

My fix

48CBA 00009999A93FC78424880000007B14AE47C784248C000000AE47F13FC784

 

What this fix does is to change the skid friction from about 1.785 to

about 1.875. The actual numbers in SIM1.DLL have a lot more decimal

places than that.

 

If you want to try different values the following may help.

 

This is a bit techie so if you can’t sleep it may help.

 

The numbers you are dealing with are called Single precision floating

point, (32 bit). When displayed in Hexadecimal, (Hex), each pair of

characters forms a single Hex character, (Byte, 8 bits). This is

important when you use the Web site to translate Decimal to single.

 

To translate the numbers between Decimal and Single Hex I use

 

Decimal to Single Hex http://babbage.cs.qc.edu/IEEE-754/Decimal.html

Single Hex to Decimal http://babbage.cs.qc.edu/IEEE-754/32bit.html

 

Be where! In the above Web site the Bytes are reversed. So in XVI32,

where you have E17AE43F, you must enter it as 3FE47AE1 on the web page.

 

When you convert Decimal to Single Hex, if you got the result 3FF147AE

you must put it in XVI32 as AE47F13F.

 

Using my fix above as an example, I entered the original Microsoft

value, (in reverse) 3FE47AE1 into the Single Hex converter. This gave

the Decimal answer 1.7850000. I wanted to increase it a bit so I

guessed at 1.885. I entered 1.885 into the Decimal to Single Hex

converter and go the answer 3FF147AE. So remembering to reverse this, I

entered AE47F13F into XVI32.

 

That’s all there is to it.

 

Just in case you are still awake, that’s the end of the lesson.

 

There are various other things you can change using this technique. I

have only shown how to edit the skid for Asphalt and Concrete, you can

do other surfaces. Some people have played about with brake friction

which was the subject of the German web site. Some say this is great

and some not.

I think with all of these “fixes”, it depends on the model you are

flying.

 

If you try any of this I would be interested to know how you get on.

 

Some info on locations of things you can change:

 

Tab. 1 Wheels

1) CONCRETE default Offset

a) Roll Friction 1.199 48cbc (recommended : 1.00 to 1.1 )

b) Skid Friction 1.785 48cd2

c) Brakeing coeff. 1.799 48ce8

 

2) GRASS

a) Roll Friction 1.409 48cfe

b) Skid Friction 1.785 48d14

c) Braking Coeff. 1.58 48d2a

 

....

 

4) ASPHALT

a) Roll Friction 1.199 48dc4

b) Skid Friction 1.785 48dd8

c) Braking Coeff. 1.799 48df0

 

....

 

24) TARMAC

a) Roll Friction. 1.199 492a

b) Skid Friction. 1.785 492c0

c) Braking Coeff. 1.799 492d6

 

And this is an example for the actual code for table 1, Wheels,

Concrete:

 

code:48CB8 840000009999993FC78424880000007B --> 1.199 Roll Friction

48CC8 14AE47C784248C000000E17AE43FC784 --> 1.785 Skid Friction

48CD8 249000000066666666C7842494000000

48CE8 6666E63FC78424980000007B14AE47C7 --> 1.799 Braking coefficient

Wow there ya go. Who would have thought it was so easy. :p

Although to be honest, it looks like the calculations to develop a EmDrive. :D