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Suspension

Started by Phathry25, December 22, 2015, 01:15:53 AM

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Phathry25

What position should the suspension be in when measurements are taken?

What is spindle position?  How is it measured?

What is shockminlength?  RestLength? (in CFG file)

Is there a setting so I can have my tie links in front of the spindle?  When I try right now I get reversed steering.

Guessing by the other cars the bottom of the car should be at 0 in the scene.  Suspension in full droop?  At desired base ride height?  Fully compressed?

Obelix90

December 22, 2015, 01:31:55 PM #1 Last Edit: December 22, 2015, 02:12:20 PM by Obelix90
Hi Phathry,
to have the tie links in front of the spindle, there is an option in the .cfg file.
steer
{
racklength = 0.095
rackdirection = 1

ratio
{
range = 695, 0, 695
setting = 0
}

lock = 28.5
}

I think, rackdirection=1 or 0 should solve your problem.

I'm not sure, but I think the shockminlength is the lentgh of the shock, when it is fully compressed(minimum distance between the two red points in the debug mode). The distance which the shock can travel should be the restlength.

I'm also interested in this information, so I hope somebody could tell more. :)



Phathry25

Thanks for the help.  I redid my GEOM file with the information provided, and the steering was correct, but the shock information still doesn't jive.

In the example cars, rest length is always shorter than min length.

Guess I'll just have to hunker down and wait for the boss to get to me.

PiBoSo


"shock_minlength" is added to the spring / damper length and to ride height to calculate, in realtime, the distance between the two shock links.
"Obviously your ambition outweighs your talent".

Phathry25

So we're clear.

I build the car with all the suspension bits fully compressed and then add everything from there, right?

What is shock rest length then?

Phathry25

Built my car with the suspension fully compressed and got the suspension to rebound and set its ride heights correctly, but it compresses way too much. Like the tops of the wheels will touch with a big enough impact.

What am I missing? Where did I go wrong?

Phathry25


Obelix90

Maybe your shock_minlength is to short or your spring to soft?

Phathry25

Spring should be irrelevant, I am trying to hit the bump stops after all.

Raising the minlength values just pushes the shock_bodylinks higher.  It doesn't seem to effect travel in either direction.  RestLength is for sure the amount of rebound travel.

I was looking at it as minlength is the absolute minimum length between the two points, or where the bump stop should be, it's not.  Or I have something else messed up.  My best guess after tweaking everything every which way is that travel is limited by the distance between the two shock mounting points.  But I know that's not right either because I did some testing with the F2000, and while the distance between the two shock mounts is pretty long, it doesn't travel upwards much, but does travel downwards about 2 feet.

Obelix90

January 01, 2016, 07:21:18 PM #9 Last Edit: January 01, 2016, 07:37:03 PM by Obelix90
Hi,
I also have a problem with the suspension. When the car is standing still, the front suspension compresses to much (about half of spring lentgh). It makes no big difference, if I set the spring to 75 N/mm or 10000! N/mm but when I jump the suspension decompresses to the maximum length. I'm using the MacPherson suspension like the FMK. Is this the same problem you like yours, Phathry?

What type of suspension do you use?

Quote from: Phathry25 on December 28, 2015, 03:20:53 AM
Raising the minlength values just pushes the shock_bodylinks higher.
The shock_bodylink is a attached to the chassis. How could it be pushed upwards?

Edit:
Quote from: PiBoSo on December 23, 2015, 10:51:38 AM
"shock_minlength" is added to the spring / damper length and to ride height to calculate, in realtime, the distance between the two shock links.
spring / damper length is RestLength, right?

Phathry25

I have a double wishbone at the front with 16" of travel. My ride heights look about right and so does my droop travel, it's just that I can't hit the bump stops. Maybe I'll just set the packers super long until I can get the desired amount of compression travel.

Obelix90

I found my mistake. I forgot to change the KeeperSpring value in the .CFG file. Now it works much better.

Phathry25

Quote from: PiBoSo on December 23, 2015, 10:51:38 AM

"shock_minlength" is added to the spring / damper length and to ride height to calculate, in realtime, the distance between the two shock links.

What is rest length?

PiBoSo

Quote from: Phathry25 on February 03, 2016, 03:50:40 AM
Quote from: PiBoSo on December 23, 2015, 10:51:38 AM

"shock_minlength" is added to the spring / damper length and to ride height to calculate, in realtime, the distance between the two shock links.

What is rest length?

The length difference between the uncompressed and fully compressed spring.
"Obviously your ambition outweighs your talent".

Phathry25

I hate to be a bother, but I want to be sure I am doing this right.

I define my suspension in the GEOM file as it would sit fully compressed. Ride height is added from there. Shock min length is the minimum distance between the two shock mounting points, rest length is then added to shock min length to get your maximum downwards travel.

Or no?