pbura
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| posted on 27/4/04 at 09:52 PM |
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quote:
Originally posted by Northy Which program should I start off with as a beginner? Do you just plug numbers in?
I'm an RC guy 
I use both Wishbone and Suspen. Wishbone is easier for setting up the problem and for adjusting pivot locations to improve camber, or whatever, in a
given chassis position. It sort of bites for dynamic modeling, though, which is where Suspen comes in. In Suspen, you just punch arrow buttons and
the chassis bumps and rolls as you please.
This routine works well for adjusting an existing design, but for a from-scratch design I'd rather draw it (like the example on my website).
A hybrid technique, like sketching the chassis to set the uprights, track, ride height, roll center height, swing axle length, and inboard lower pivot
location, then 'fishing' with Wishbone for the upper pivot, would work pretty well, too.
Digger Barnes has been working on a spreadsheet, too, and he says he'll be done with it soon. That'll be interesting to see.
These methods I'm using are low-rent, by the way. There's a program called SusProg3D that will determine pivot locations by reiterative
testing, probably the way to go for most people.
Pete
P.S. You RC guys are outrageous; best automotive tech info on the web!  
[Edited on 27/4/04 by pbura]
Pete
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Northy
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| posted on 27/4/04 at 10:00 PM |
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quote:
Originally posted by pbura
I use both Wishbone and Suspen. Wishbone is easier to set up the problem and to adjust pivot locations to try to improve camber or whatever in a
given chassis position. It sort of bites for dynamic modeling, though, which is where the Suspen comes in. In Suspen, you just punch arrow buttons
and the chassis bumps and rolls as you please.
This routine works well for adjusting an existing design, but for a from-scratch design I'd rather draw it (like the example on my website).
A hybrid technique, like sketching the chassis to set the uprights, track, ride height, roll center height, swing axle length, and inboard lower pivot
location, then 'fishing' with Wishbone for the upper pivot, would work pretty well, too.
Digger Barnes has been working on a spreadsheet, too, and he says he'll be done with it soon. That'll be interesting to see.
These methods I'm using are low-rent, by the way. There's a program called SusProg3D that will determine pivot locations by reiterative
testing, probably the way to go for most people.
Pete
P.S. You RC guys are outrageous; best automotive tech info on the web!
Cheers Pete,
I'm in no rush, I'm not taking the bloody thing apart again now. Will be a winter upgrade I think
It amazes me just how adjustable RC cars are these days, and how responsive they are to the smallest change. But its a littl off putting when racing,
I often just leave it as I fear making it worse!  New tyres solve most problems!
Cheers
Graham
Website under construction. Help greatfully received as I don't really know what I'm doing!
"If a man says something in the woods and there are no women there, is he still wrong?"
Built 2L 8 Valve Vx Powered Avon
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Digger Barnes
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| posted on 28/4/04 at 08:14 AM |
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quote:
Originally posted by pbura
Digger Barnes has been working on a spreadsheet, too, and he says he'll be done with it soon. That'll be interesting to see.
Yep finished the spreadsheet yesterday (quick and dirty way to see the output for now, real animations will be built into the program eventually) that
will animate the data output from my program. The program I am developing will hopefully be built along with my car build and I hope to eventually
incorporate spring mass damper calcs and Weight distributions for estimating the real suspension movement in turn and bump/droop for a set of road
conditions.
If I feel really adventurous I will even try to put in some data about friction coefficients for the tyres to get a rough idea about grip
limitations.
I am going to add a Save profile button to the project tonight and then I will mail the promised copies out.
[Edited on 28/4/04 by Digger Barnes]
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pbura
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| posted on 28/4/04 at 01:29 PM |
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That whole area of springing and weight transfer is very interesting. I haven't learned much about it yet because it doesn't come into
play until way down the pike for me, but I have found this page and site to be very provocative:
http://www.smithees-racetech.com.au/wttransworksheet.html
Pete
Pete
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Digger Barnes
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| posted on 29/4/04 at 07:31 PM |
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jcduroc and pbura check your email it is finaly ready to play with.
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Digger Barnes
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| posted on 29/4/04 at 07:40 PM |
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quote:
Originally posted by pbura
Well, I took a shot at Dave's suspension geometry, had a lot of fun, and got more behind with earning my daily bread
P.S. dont you want to calculate the rear suspension with 1" of droop rather than 1" of bump as the car will dive into a corner when on the
brakes lifting the rear?
[Edited on 29/4/04 by Digger Barnes]
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pbura
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| posted on 30/4/04 at 12:32 AM |
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quote:
Originally posted by Digger Barnes
P.S. dont you want to calculate the rear suspension with 1" of droop rather than 1" of bump as the car will dive into a corner when on the
brakes lifting the rear?
Mmmmm, because I was thinking about accelerating out of turns?
Fact is, I didn't even think about it, but I'll freely admit that I'm a tyro.
I noticed that you do the droop and roll for the rear in your program, which is very cool! It's a great start. When you get into more
interactive modeling and to use other than Sierra uprights, as are your plans, it will be a real winner. It would be fantastic to be able to watch an
animation, or fix a frame with the RC and camber figures, and watch them change as you alter pivot locations.
The camber figures for Dave's car at 1" droop, 2 degrees roll are +2.000 degrees on the loaded side, -0.925 deg. on the unloaded side,
btw. Are these OK? They're better than in your example, at least 
If anyone would like to throw in their two pence, and tell me to get back to the drawing board, or whatever, WRT the proposed changes to Dave's
suspension, I'd appreciate it. Please note that I was going for good performance while keeping the changes simple. The sum total of the
changes were:
--Raise the ride height 0.75"
--Raise the bottom wishbone mounting bracket 1.5" (no change in the wishbone).
--Move the upper pivots in by a few inches along the same tubes a few inches, and make new wishbones to suit.
Opinions are like a**holes; everybody's got one. Anyone game to share theirs? Opinion, that is!
Pete
Pete
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jcduroc
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| posted on 30/4/04 at 04:35 PM |
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quote:
Originally posted by Digger Barnes
jcduroc and pbura check your email it is finaly ready to play with.
No light at the end of the tunnel yet.
Just f*****g Viagra advertisements...
Joćo
JCM
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Digger Barnes
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| posted on 30/4/04 at 05:02 PM |
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No light at the end of the tunnel yet.
Just f*****g Viagra advertisements...
Joćo
Didn't you get the program? if not u2u me your address again
cheers gareth
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jcduroc
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| posted on 30/4/04 at 06:54 PM |
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quote:
Originally posted by Digger Barnes
No light at the end of the tunnel yet.
Just f*****g Viagra advertisements...
Joćo
Didn't you get the program? if not u2u me your address again
cheers gareth
I got it (just problems w/ too many trash msgs in my ISP provider, I guess)
I had a quick look but I'm going to try it fully tonight.
BTW, where does ET41 come from? I thought Sierra normal wheels were ET38.
Joćo
P.S.: I'll post you my remarks on Sunday (I hope).
JCM
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Digger Barnes
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| posted on 1/5/04 at 06:15 AM |
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quote:
Originally posted by jcduroc
BTW, where does ET41 come from? I thought Sierra normal wheels were ET38.
ET 41 comes from the wheels I had on my donor (XR4x4) well thats what it has stamped on them anyway.
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Northy
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| posted on 1/5/04 at 08:53 AM |
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Digger,
Could I have a copy please?
Cheers
Graham
Website under construction. Help greatfully received as I don't really know what I'm doing!
"If a man says something in the woods and there are no women there, is he still wrong?"
Built 2L 8 Valve Vx Powered Avon
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F1 Mini
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| posted on 1/5/04 at 09:27 AM |
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I would love a copy Please Sir.....
[Edited on 1/5/04 by F1 Mini]
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Digger Barnes
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| posted on 1/5/04 at 11:19 AM |
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Sure thing Graham and F1 just U2U an address and I'll send a copy out.
Cheers
P.S. Pete that Milliken & Millikin book will be winging its way to me very soon, I simply must have it.
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jcduroc
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| posted on 2/5/04 at 02:45 PM |
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quote:
Originally posted by Digger Barnes
P.S. Pete that Milliken & Millikin book will be winging its way to me very soon, I simply must have it.
Gareth
I have it on paper; anything in particular you want to know right now? (Any formula...?)
Joćo
JCM
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Digger Barnes
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| posted on 2/5/04 at 03:50 PM |
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Thanks Joao (sorry I don't know how to do the a properly in your name)
I should have the book on Tuesday or Wednesday. As it is a bank holiday over here I shall be relaxing for a day or two (very little on the car or the
misses will kill me) so thanks but i should be ok.
But I am sure you have a book or two I would not mind a few pages from so I might email on the scrounge later on in the build (Aerodynamics
anyone).
Cheers
Gareth
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jcduroc
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| posted on 3/5/04 at 09:00 PM |
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quote:
Originally posted by Digger Barnes
Thanks Joao (sorry I don't know how to do the a properly in your name)
Gareth
ALT+0227 (on the num keypad) like this: ć
Of course keyb po doe it directly.
Joćo
[Edited on 3/5/04 by jcduroc]
JCM
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dblissett
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| posted on 8/5/04 at 08:16 AM |
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avon irs
hello pete i now have the avon dimentions for you
the bottom wishbones,brackets and upright pivot points realative to the road are all the same although ride height is 4 1/2 to 5 inches
the top wishbones are longer but mounted higher at their brackets
ps i am half way through your changes as my new daughter is slowing things down
could you compare this with changes i am doing as northy and other are interested
cheers dave
 
Rescued attachment avon.JPG
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SilverFox
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| posted on 7/8/04 at 05:36 AM |
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Pete, Have reviewed this topic several times - excellent stuff. When you refer to book suspension, is your analysis for the Cortina or the Sierra
uprights? Do folks generally use the same (per book) or different inboard pickups to accommodate the wider Sierra configuration or when going ++ etc?
Can you get a "non-migrating" front RC down to say 2" with the Sierra upright on book chassis swivel points
Alf
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pbura
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| posted on 7/8/04 at 11:25 AM |
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quote:
Originally posted by SilverFox
Pete, Have reviewed this topic several times - excellent stuff. When you refer to book suspension, is your analysis for the Cortina or the Sierra
uprights? Do folks generally use the same (per book) or different inboard pickups to accommodate the wider Sierra configuration or when going ++ etc?
Can you get a "non-migrating" front RC down to say 2" with the Sierra upright on book chassis swivel points
Alf
Hi Alf,
I did up the book front suspension with Cortina uprights in the suspension programs. To be honest, I may be off very slightly because of bracket
heights, but the results were close to what MikeP got in a similar exercise. Differences were so minor that I haven't made the effort to get it
100% accurate. I'm not building a book car anyway
For a wider car, increasing the distance between the chassis pickups (as in a McSorley +4) gives very similar geometry.
Changing the uprights, e.g., using cut-down Sierra struts, will probably give a different geometry (camber and RC behavior), but I've never
studied it out.
I encourage everybody who is building non-book to learn all they can about their suspension. If I were to design Dave's rear from scratch (his
was already built), I'd probably go for less camber gain in bump, but who's to say I'd be right?
If you or anyone else needs a hand setting up one of the suspension programs, or would like some feedback on a suspension setup, please feel free to
e-mail or U2U.
All the best,
Pete
Pete
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iwbunting
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| posted on 7/8/04 at 07:52 PM |
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Irs - Are we missing something
I am building a mcsorley +442 with rear irs.I have also read the bibles and have based my wishbones on book calculations and ......... I have built in
some adjustments,firstly the top wishbone is approximately 2/3rds of bottom and is fitted with a rose/ball joint at the upright end giving about 25mm
adjustment in length.Secondly and foremost on the chassis side i have welding in sets of brackets with varying hole positions in the vertical plane,by
doing this it has given me the ability to infinately adjust camber,height and roll centres by merely raising or lowering the inner pivot points.
Hope this might be of help.
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SilverFox
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| posted on 8/8/04 at 01:48 AM |
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Many thx for the clarification Pete. I will do a search for key dimensions of the Merkur/Sierra upright and get back to you
(probably e-mail) with a first cut.
unfortunately don't have MS quickbasic or any of the other tools as yet - a winter project possibly.
Have to tried Digger Barnes' software?
Dave. the only adjustability I am thinking of at present is raising the mushroom insert. My arm lengths are 17 3/4" and 12 1/2" attached
to the book swivel points.
Alf
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SilverFox
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| posted on 8/8/04 at 03:01 AM |
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Sorry, correction 17 1/2" and 12 3/4"
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pbura
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| posted on 8/8/04 at 11:59 AM |
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quote:
Originally posted by SilverFox
Have to tried Digger Barnes' software?
Yes, and it was looking very promising, too. In fact, it's presently based on Sierra uprights, so you ought to e-mail him for a copy.
Following are some screen shots showing the upright dimensions:
 
Rescued attachment Sierra1.jpg
Pete
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pbura
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| posted on 8/8/04 at 12:02 PM |
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2nd pic:
 
Rescued attachment Sierra2.jpg
Pete
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