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VHPA v3.1.4 [updated 26/03/10]
(613 posts, started )
Hey Bob thumbs up for the great job again.
One question though.
After version3.0.0, the spring load graph displayed on damping tab is not affected by live settings such as steering or throttle.
Is that normal?
Yes. The live settings allow you to view the vehicle in one instant of time given your current parameters. As such, the live settings do not affect acceleration, deceleration, gearing or damping, since those all involve the vehicle in multiple time frames. It was a bug back in v3.0.0. At some point I will add many other conditions to test the dampers in, rather than just the LFS style drop that there currently is.
Ah ok thanks for the answer.
In a way I used that graph to see in detail the pitch change ,while turning, caused by the difference of the ARB/spring ratio between the two ends.



I will stick with the spring analysis tab even if i can't see the differences so clearly at these graphs.
Aha, never thought about that. Well, whenever the new damping analysis is added, you'll be able to use it for that again.
re: dp1
One of the things that has been bugging me about LFS and as a result, VHPA is the values used for the damping rate. From what I have see (at least here in the US) is that dampers are rated at .52m/s or 20in/sec.

It is virtually impossible to get these values converted over to 1m/s. Well, it wouldn't be so bad if the damping rate were linear, but again, in most cases it doesn't seem to be. I only have experience with road going dampers though, so it might not be true for race dampers.

The modern dampers I am familiar with are very progressive similar to a second order differential equation where the rate of damping reduces as the rate of motion increases. The highest rate of change is between 0 and .3m/s. After that, the slope drops off considerably and becomes more linear.

So, if you get a value from a damper manufacturer, say Bilstein, they will give it to you at .52m/s and it will be something like 2000n. You can't really just double it to get the proper m/s value and even if that did match up, it wouldn't work for slower rates, the values would be much too low.

Anyway, I don't know of a way around this.

But it would be nice to either a) allow entry at different rates and then offer an approximation for variable rate dampers. and b) find out exactly what Scawen does to calculate damper values given a single spot value at 1m/s (I think we all assume it is just linear now).

If we knew exactly, then you could put in values that would give you the correct damping at the slower rates (which are the most important) and would probably be a bit high for the faster rates (assuming that Scawen takes that into account, which I am sure he does).
Yeah, we have always assumed dampers are linear in LFS. I know that dampers are never like that on modern cars. At work I've got some dampers tables for a Ferrari and I was surpised just how non-linear they are. I'm due to mail Scawen a bunch of questions, I'll make sure I get something about this on this list. I just pray it doesn't get too big, I don't want to email the man a book now do I.
Quote from Bob Smith :Yeah, we have always assumed dampers are linear in LFS. I know that dampers are never like that on modern cars. At work I've got some dampers tables for a Ferrari and I was surpised just how non-linear they are. I'm due to mail Scawen a bunch of questions, I'll make sure I get something about this on this list. I just pray it doesn't get too big, I don't want to email the man a book now do I.

here's a link to a dyno test result of the dp1 proto shocks - they are ohlins ST-44 (and yes, they're quite soft, but it was a first shot at it).

http://www.dpcars.net/misc/shocks.jpg
Quote from dpcars :here's a link to a dyno test result of the dp1 proto shocks - they are ohlins ST-44 (and yes, they're quite soft, but it was a first shot at it).

http://www.dpcars.net/misc/shocks.jpg

Wow, that is interesting. The bump and rebound have about the same rates.
With the street dampers I have been looking at, bump is usually much lower than rebound. Rebound is usually 2x or more than bump. Which matches up with most of the stuff I have seen written about suspension setups.
Of course the dp1 is a special little car .

Is there such a thing as motion ratio for the dampers like there is for the springs? I wouldn't think so, but thought I would ask.
Well, the usual installation method is coil over dampers, so the dampers should be affected by the motion ratio in the same way as the springs, but that wouldn't affect the overall shape of the graph. I've seen data for bump being set as soft as 3 to 4 times softer than rebound, in certain circumstances.
Quote from Bob Smith :Well, the usual installation method is coil over dampers, so the dampers should be affected by the motion ratio in the same way as the springs, but that wouldn't affect the overall shape of the graph. I've seen data for bump being set as soft as 3 to 4 times softer than rebound, in certain circumstances.

there are lots of factors that affect suspension setup. generally, stiff rebound helps control body pitch/roll at the expense of mechanical grip. ideally the purpose of the shocks is to keep the force at the tyre/pavement interface as constant as possible, both at high and low frequencies. in practice the shocks also have to control the body motion to limit undesirable geometry changes, unless the spring rate is high enough relative to vehicle weight that the body essentially doesn't move. this is how race cars end up with spring rates that may seem ridiculous in terms of traditional 'natural frequency' approach which is comfort-based rather than performance-based.

other factors are things like unsprung weight and sprung/unsprung ratio, geometry specifics, tyre particulars, ad nauseum.
I've got another preview release for you to test out again. Changes as usual can be seen on my to-do list. I still need to add licence key generation and commercial unlocking support, as well as the usual manual and website updates. Don't worry, VHPA will remain free for LFS and private/educational use.

If anyone who tests out this preview could let report any bugs you might find, that would be great. The zip contains just includes the updated exe and updated vehicle files (so needs to be extracted over your existing VHPA install).

v3.1.2 is planned to be the first of three minor releases, essentially polishing the app before I continue working on some meaty stuff (tyre physics next I think, then suspension, and so on) that will come in v3.2.0 and onwards.

FILE REMOVED, IT WAS BUGGED, SEE LATER POST FOR FIXED VERSION
I hope it's an easy one.

When I try to open any setup file, I get an error message from the app “run time error – Subscript out of range”
Any setup? I tried a couple but it works here with all the default sets. Please attach a set it crashes with so I can reproduce.
Yes it does that with any set, even with defaults.

I did try to load vehicle data before loading a setup for that car, but then again an other error message appears, this time from win, “AppName: vhpa.exe AppVer: 3.1.0.2 ModName: oleaut32.dll
ModVer: 5.1.2600.2180 Offset: 00004cb4

Also it freezes by just loading FOX vehicle data. Error message “Run time error – Overflow”

Did you try to download the files you have attached? maybe there is something missing?
Or I just have problems with my hardware setup?? Tomorrow I will be in front of my main pc so I will test it there again.
(btw older VHPA vertions work fine here )


Anyway attached a setup but if any other setup works with your VHPA vertion, then I guess this is going to load fine too.
Attached files
FOX_ky2r kd R2.set - 132 B - 502 views
Aha, I think I've sussed it.

I'm guessing you skipped this step:

Quote from Bob Smith :The zip contains just includes the updated exe and updated vehicle files (so needs to be extracted over your existing VHPA install).

If I extract that zip to a new folder, then I get the overflow crash when trying to load in FOX (but not XRG... only two I've tested so far). I'll look into curing that.

Edit: that set seems to kill VHPA though, even if installed correctly, yet none of mine seem to have that problem.
Edit again: OK it's doing it with all sets at work but not at home. Must be something to do with the recent setups list this version adds.

Thanks for the report, I'll dig into this when I get home tonight
Silly me
I am on a pc with 56k connection these days and I just give a quick look at threads - posts so I must have missed that bit.
And I was wondering how can it be only 300k

I hope this report wasn't complete waste of time
Quote from kaynd :I hope this report wasn't complete waste of time

No, you defintely raised some issues there that need to be fixed. VHPA should ideally be stable even if everything except the exe gets deleted.
Problems.
Hi Bob ^^.
I've got some problems here. When VHPA is loaded without any vehicle loaded, and i'm trying to load cars like: BF1, db1, FBM, FO8, FOX, FXR, FZR, XRR i got "Run-time error '6': overflow", but when i import any other car, and then import one of those above then everything is fine.
Another problem is when i load any setup from LFS setups or even one made directly from VHPA 3.1.2, I got this typical Windows XP error with option to send info to their HQ .
I cannot add new vehicles O.o(only import ones that have been already made with previous version).

BTW. You could add something like "force gear", so it could simulate acceleraction from 80-120km/h on 6th gear for example .
BTW2. I've sent You report from that error.
BTW3. Possibility to watch acceleraction in real time was nice, include it also(in my opinion ^^).
Hi Byku, thanks for the details. Not sure what to make of the error report though, only the dll seems relevant and even then that's vague. Not sure what Microsoft do with that data.

The realtime acceleration viewer is still there, I just removed the button to make room for the new controls, although after reorgansing it, there is room to put it back. For now, you can get it from the menus or press Ctrl-R.

I'll look into the bugs now.

Edit @ 18:54: fixed the overflow bug, it was trying to search the MRU setup list when it didn't exist.
Edit @ 19:46: finally solved crashing when loading a vehicle when no vehicles were auto-loaded

Version with those bugs (hopefully) fixed attached.
EDIT: FILE REMOVED, MORE BUGS WHERE FOUND
Did those bugs get cured? I didn't have time for extensive testing. I've also spotted another couple which I've fixed (not being able to select the most recently used setup was one).

Also, while it's useful to get bug reports on things that have gone wrong, anybody have anything to comment on anything that went right (i.e. the new features)?
Hi ^^.
Hi Bob, the problems that i have mentioned are fixed, everything is fine ^^. Just one thing i have spotted, and i dont know if its a bug or it should be like that. The rotating mass can be max half of the unsprung mass(ex: 30 unsprung mass, max 15 rotating mass).
"Search data for statistics" is a good idea ^^, i like it .
Yep, that is correct, as the unsprung mass is set per axle and the rotating mass is set per wheel. Previously the rotating mass was set per axle, which was confusing given that it is organised with wheel specific data.

As VHPA only currently supports 2 wheels per axle, this is fine. Once I add support for axles with one wheel, the limit will be based on the number of wheels on that axle.
Hi, after install I try to run program and this thing shows up, any help pls
Attached images
error.JPG
O.o
Something is wrong, at least I think so. I've made a car, in "acceleration times & distances" from 0-227.7(max speed) takes 120 sec, but in "search data for statistics" from 0-227 takes just 95 sec O.o. Ok, I understand, there is 0,7 km/h difference, but still, from 0-150 in "at&d" takes 11,829, but in "sdfs" it takes just 11,748. Why there is a difference? (there are differences in any other car also)

Btw. Niki download it from here: http://www.afreeocx.com/ocx/download/2873/comdlg32.ocx and then install to system32(if you're using XP, I dont know how it is in Vista ^^).
Btw2. Bob, if you want more people to test 3.1.2, announce it in the title of this thread .

VHPA v3.1.4 [updated 26/03/10]
(613 posts, started )
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