LFS Gear Ratio Calculator 2½ [deceased]

[Bob Smith]

May I present: LFS GRC v2½

For anyone who has used the old Excel spreadsheet versions (1.x): it has all the functionality of before, and then some. However it is now a standalone app written in VB and, most importantly, has support for all the S2 cars.

For people who've never seen it, GRC can:

• Tell you the speed at shift points between gears, thus making it easier to adjust them.
• Tell you the engine revs before and after shifts, to help prevent gears from being badly spaced.
• Tell you the torque available in each gear, to help limit wheel-spin.
• Perform standing start acceleration info and pick out some acceleration times (e.g. 0-60) and top speed.
• Calculate all of the vehicles aerodynamics for aero balancing and view the impacts on top speed and acceleration.
• Draw pretty graphs to provide information in a more readily understandable visual format.
• Give tyre deformation information for you to coo over (but has no real use).
• Allow you to create your own cars so that GRC can perform everything mentioned above with cars that are not in LFS by default.
• Allow you to save and load settings to save you having to continously re-enter your gearing details.
• Allow you to personalise the program so information is presented to you in the format which you prefer.

An 8 page PDF manual also ships in the zip which covers the majority of the features.

Screenshots:

click the image for a larger version


Download page - link is at the bottom of the page.

Languages supported:

• English
• Czech (Cestina)
• German (Deutsch)
• Dutch (Nederlands)
• Finish (Suomi)
• Polish (Polski)

Planned features list: - now added in Project3

• add a 7th gear for the BMW Sauber
• add a torque-split slider for AWD cars, for better acceleration modelling
• add separate front and rear tyre choices, for better acceleration modelling
• optimal shift point calculations based on estimated torque curve (rather than weird formula that worked for LFS 0.3x)
• automatic gearing spacer
• make tyres load sensitive
• .csv export for acceleration data (will contain more data than is available in the text box)
• LFS Setup (.set) file loading/saving (Read Only)

Planned features list: - not added into Project3... yet

• automatic calculation of top gear rpm
• add a graph for tractive effort vs. speed (currently only time can be on the x axis)
• add a graph for speed vs. distance

Anyway hope this helps, as usual feedback is always welcomed & appreciated.

Cheers all, good racing


Update: LFS GRC is now a "deceased" project, I am no longer working on it. I am now working on a new app instead, a preview version is currently available here.

[the_angry_angel]

On the version I was testing for Bob some time ago, there was a save feature. I believe its still in there somewhere.

As for saving and loading .set's we're still trying to figure out exactly what all the bits in the .set file represent, and the format may change - so I'm guessing Bob will have that in the works as soon as its "final".

Incidentally Bob - nice beard

[Bob Smith]

Yeah, there is still "File, Save As" you know.

The .set specification is good (thanks to Colcob). I just need to learn how to read/write binary files in VB now.

I thought all programmers had to have a goatie?

[the_angry_angel]

Yup - I did until a few weeks ago, but i've decided to grow it back again (I felt naked, plus at work I didnt have anything to stroke when people asked me to estimate coding time)

I think the problem with the .set format, is that its possibly subject to change before the "full release" - ofc, it wouldnt be too difficult to change, just a pain in the arse

[colcob]

We have php driven .set file reading and writing working fine at the moment, but I'm not familiar with VB myself, so I dont know how easy binary file reading/writing is. Shouldnt be a problem though.

As for saving and loading .set's we're still trying to figure out exactly what all the bits in the .set file represent

Certainly not, the spec is there in B&W in the programmers forum. Pay attention at the back

[the_angry_angel]

sorry I must've missed that.

I could've sworn there was a few things that werent spacers, but werent identified. I'll try to keep up

[Bob Smith]

.....2.2.....

Highlights of changes: Added aero balance stuff, put the downforce onto the tyres and have made up a tyre stiffness equation (which affects how the tyre deforms), which totally changes the deformation compared to the old "balloon" style deformation.

[colcob]

Your site's down Bob.

[Bob Smith]

Already on it. Excessive bandwidth usage my arse, seems my ISP can't count. This is my last month with them anyway. A shame, since they've been very good all year.

[the_angry_angel]

If you wish, I can mirror the GRC files at least Bob.

[Bob Smith]

Noo, can't let this thread be at the bottom.

Anyway, v2.2.1 fixes the tyre frequency equation as discussed here the past few days, and also removes the about box and puts it in the empty space left on the info tab caused by the addition of the aero tab.

[Bob Smith]

After an all day coding session Thursday (to 2am), again Friday (to 3am) and once more today (to 4am), may I present GRC v2½.

Lots of new features (but still no .set file import/export)

Very tired now... going to sleep

Enjoy

[flyby3d]

Originally Posted by Bob Smith

After an all day coding session Thursday (to 2am), again Friday (to 3am) and once more today (to 4am), may I present GRC v2½.

Lots of new features (but still no .set file import/export)

Very tired now... going to sleep

Enjoy

Great job as always! Keep up the good work

[Madman_CZ]

As always bob nice work..... tho really u need to spend sometime away from lfs.......... u dont want to end up like that guy in china...

[Gizz]

bob!!

im on win98SE and and when i try to open the program it gives me the following....

runtime error out of memory '-2147024882(8007000e)'

any ideas m8??

[StewartFisher]

Nice work Bob! How do you calculate the change in front/rear load distribution caused by the aero settings?
I've made a suspension calculator spreadsheet which takes into account the variation of weight distribution with driver and fuel load but I've not managed to get all the information about downforce yet.
Basically I need the locations of the point of action of the front wing, rear wing and undertray. I can calculate the downforce but don't know exactly where it acts on the car.
The only other thing I need for my spreadsheet is the unsprung masses of the cars...any ideas?

[colcob]

Yeah, we've got all that stuff. Drop me a PM as a reminder and send it you over.

[Bob Smith]

Do you actually have wing locations sorted now Colcob or are we still going with my guesstimates?

Originally Posted by Gizz

any ideas m8??

Nope. Not seen that error before. Are you sure you have the latest versions of the DLL/OCX files used by GRC? Other than those it is self contained.

Any more experienced programmers out there have any ideas?

[Gizz]

you mension a DLL? in the missing files there are only .bat files and ocx files no dll's am i missing somthing ?? (i normaly am like the apex )


tnx bob

[Bob Smith]

Should be 3 OCXs and 2 DLLs. You must have them installed, as an error should pop up saying they are missing if they aren't, and the program won't load (but not crash). The ones in the zip should be the latest versions, so I was ruling out old versions of the libraries (not a likely cause...).

[Gizz]

bob in the missing files i only have the 3 .bat (for diff versions of win) and 3 ocx files...

could you point me in the rite direction for those DLL's its gota be worth a try

PS. the program doesnt load at all i just get that error as soon i hit the exe...

tnx again

[Bob Smith]

Well, you can give it a go but I really don't think this will help, I just can't think of anything else. Have you any other PCs to try it on? I've seen it run on Win98SE before so that itself shouldn't be a problem.

The files needed by GRC are (you can google for them):
COMCTL32.DLL
COMCTL32.OCX
COMDLG32.DLL
COMDLG32.OCX
MSCOMCTL.OCX


...but they are all in that zip, I just downloaded it to make sure the online one matches the one on my drive, and it does. There should be 9 files. Check to see if system files are being hidden.


No other programmers have any ideas as to what my be causing the problem for Gizz?

[Bob Smith]

Still nobody with any ideas to help Gizz? Oh well.

Anyway, to happier news, v2.5.1 is here, just some small maintenance before I get around to adding some more features in a few days:
* added weight transfer caused by acceleration
* replaced the logo with the one I meant to put in v2½
* fixed 5 small bugs that hopefully no-one noticed anyway

[JTbo]

Originally Posted by Gizz

bob in the missing files i only have the 3 .bat (for diff versions of win) and 3 ocx files...

could you point me in the rite direction for those DLL's its gota be worth a try

PS. the program doesnt load at all i just get that error as soon i hit the exe...

tnx again

Could you please write here names of those .bat and .ocx files, would help a lot in helping

[Stuff]

Also Gizz, and Bob, don't forget about the essential .dll file, the VB 6 runtime.
It can either be found in this spiffy unofficial service pack or simply at the M$ site.

Might help

[StewartFisher]

Good work again Bob
One thing I've been meaning to ask you about since I 'discovered' it a few days ago is the effect of drag on the load distribution. I was trying to add downforce to a weight distribution spreadsheet I made and tried to calculate the locations of the three downforce points on the FXO GTR.
It's a standard three unknowns requiring three simultaneous equation problem so I used F1PerfView to give me the wheel loads for three levels of downforce all at 125mph. The locations my calculations gave me were completely wrong so I investigated...

I was taking moments about the rear axle to calculate the load distribution which means that ALL forces which have a moment about the rear axle must be included. This includes drag! I was just wondering whether your program takes drag into account when calculating the load distribution?

Oh, and I spotted a mistake in the latest version of the Advanced Setup Guide. You removed all the stuff about downforce affecting suspension frequencies from the 'Suspension' section but not the 'Downforce' section (it's on page 26).

[Bob Smith]

Originally Posted by Stuff

Also Gizz, and Bob, don't forget about the essential .dll file, the VB 6 runtime. ...
M$ site.

Ah cheers, have added a link to that on the download page now. Well done from refraining from mentioning APIs.

Originally Posted by StewartFisher

Good work again Bob
I was taking moments about the rear axle to calculate the load distribution which means that ALL forces which have a moment about the rear axle must be included. This includes drag! I was just wondering whether your program takes drag into account when calculating the load distribution?

Do you mean the weight transfer caused by aero forces not acting at the height of CoG? If so, then no (not even for non-downforce cars). At the moment I'm working with driving force and rolling resistance working at ground level, and drag sufficiently above the CoG height to remove any forward weight transfer caused by rolling resistance but not enough to create any rearward transfer. So basically, only accleration or braking causes weight transfer, not deceleration caused by coasting.
I would like to include these effects but have any data to work with. Even my wing/undertray x axis locations are guesstimates.

Originally Posted by StewartFisher

Oh, and I spotted a mistake in the latest version of the Advanced Setup Guide. You removed all the stuff about downforce affecting suspension frequencies from the 'Suspension' section but not the 'Downforce' section (it's on page 26).

ta

[StewartFisher]

Originally Posted by Bob Smith

Do you mean the weight transfer caused by aero forces not acting at the height of CoG? If so, then no (not even for non-downforce cars). At the moment I'm working with driving force and rolling resistance working at ground level, and drag sufficiently above the CoG height to remove any forward weight transfer caused by rolling resistance but not enough to create any reward transfer. So basically, only accleration or braking causes weight transfer, not deceleration caused by coasting.

Sort of, but surely it doesn't matter where the aero forces act relative to the CoG? I haven't thought about it in great detail but surely any force which does not act through one of the axles must be taken into account when calculating load distribution?

I would like to include these effects but have any data to work with. Even my wing/undertray x axis locations are guesstimates.

I would have tried it myself but 6 unknowns would require 6 sets of RAF data and 6 simultaneous equations...no thanks!

[Bob Smith]

Originally Posted by StewartFisher

Sort of, but surely it doesn't matter where the aero forces act relative to the CoG? I haven't thought about it in great detail but surely any force which does not act through one of the axles must be taken into account when calculating load distribution?

It's the CoG height that matters. When accelerating, the force is acting at ground level, and assuming a non-zero but positive CoG height, there must be rearward weight transfer. If you throw away your internal combustion engine, and strap a jet engine to the roof, there will now be forward weight transfer under acceleration.

Likewise with deceleration, the brakes are at ground level, causing forward weight transfer. Throw that jet engine into reverse and you'll get rearward weight transfer under deceleration. The aero drag of the car is the same, it most likely acts above the CoG height, so you get more rearward weight transfer the faster you go (irrelevant of propulsion). And the rolling resistance is below the CoG height, causing the opposite.

So taking a car of 50:50 weight distribution and letting it coast down (and no engine braking) from a high speed, what will we see? The car will be rear heavy as the aero drag slows the car. Eventually the aero drag dies off and rolling resistance becomes the dominant resistance. This switch usually happens about 35mph. Assuming the aero was acting as far above the CoG as the rolling resistance is below it (unlikely I agree), the car will be back at 50:50 weight distribution. And finally, the last bit of deceleration will cause the car to get front heavy (just like prodding the brakes).

The magnitude of these affects will (in most cases) be reasonably small though (relative to actually using the brakes, or firing up the afterburner). So it's nothing you would need to worry about too much. Interesting none the less.


At this point I'm hoping everything I said is accurate or I'm going to look like an idiot.

[Stuff]

Originally Posted by Bob Smith

Ah cheers, have added a link to that on the download page now. Well done from refraining from mentioning APIs.

To each their own, programming methods... I gave up a while ago trying to convince people that API is the way to go in VB6. I'm currently learning Java so no need anyway