fsae suspension

[Abhilash Saksena]

hey guys... i am looking forward to design a suspension for our fsae car... the thing is this is the first time my university is doing smthing like this and i hv no clue where to start from and how to start... i do have lotus suspension analyser but other than that what should i read through and how exactly should i proceed?

[Bemo]

You must be kidding. Maybe you should read the "Read this first" threat of this forum.

You're obviously too lazy to do any research on your own (there's plenty of literature recommended on this forum). This is NOT how this works...

[acedeuce802]

^This.

Honestly, if you don't have any idea where to start, you haven't done the slightest bit of research, and have slim chances of getting it complete, since we're not going to hold your had through the process. Follow Bemo's suggestion of the "Read this first" thread, use the "Find" button, and figure out which books/articles/tech papers to read, and then if you're still confused, come back with a better understanding of the subject.

[SteveHarasym]

Yeah man, that is way too general of a question. Start with the competition rules and the "Read this first" thread, and go from there.

[Canuck Racing]

Well since everyone is doing it:

Start with the "Read this first" thread.

And since you'll probably have a legitimate question later that everybody is too afraid to admit they don't know the answer to themselves, "FBD that shit."

I'll even through in a few other generic questions to consider when posting your own: "What is your goal here?" "How will that help your team?" "What load path is the _________ going to take?" "Are you only doing this because somebody else did?" and "Have you tried doing any research?"

Now of course, nearly all of these questions will have occurred to you, and you've probably spent some time thinking about it and just don't know. Maybe you're a freshman thrown in over your head or someone who barely speaks English from a country without good engineering resources or that censors their Google results, which is why you came to this forum in the first place to ask your question. But unfortunately we now live in a time where nobody here is going to do your work for you.

So yes, go back and start with the "read this first" thread. You'll find all sorts of books and articles there. Freshen up on those, talk with any vehicle dynamics professors and experts you can. Herb Adams has a great very basic book for beginners to suspension design and tuning though the name of it escapes me right now.

[Edward M. Kasprzak]

But unfortunately we now live in a time where nobody here is going to do your work for you.

Why is this unfortunate?

While I often wish this forum was just a little kinder to those who need some direction, I don't think anyone should ever expect this forum to do someone's work for them.

[Warpspeed]

Originally posted by Abhilash Saksena:
hey guys... i am looking forward to design a suspension for our fsae car... the thing is this is the first time my university is doing smthing like this and i hv no clue where to start from and how to start... i do have lotus suspension analyser but other than that what should i read through and how exactly should i proceed?

[Warpspeed]

OOPS, hit the trigger too soon.

How should I proceed is not such an unreasonable question.

1/ Read the rules through very carefully.
2/ Work your way through the recommended reading list provided on this Forum.
3/ Research what other entrants are doing, or have done in years past, and try to understand WHY they did it that way.
4/ Figure out a plan of action, taking into account all your own available resources and limitations.
5/ For a very first effort, keep it simple, and just try to make a basic drivable reliable car that will get you right through the competition to the very end.
6/ Your aim should be just to to FINISH and gain some points in every area but gain significant experience for your next attempt.

[RaceCatt69]

start by stopping. suspension on an FSAE car is not a necessity. put your efforts elsewhere, but dont put them all in one basket as they say

[SteveHarasym]

Originally posted by RaceCatt69:
start by stopping. suspension on an FSAE car is not a necessity. put your efforts elsewhere, but dont put them all in one basket as they say

You, sir, should also read the rules and/or stop giving blatantly wrong advice. It is necessary to have a suspension. See T6.1.1

[Abhilash Saksena]

^thanks a lot tony... will try to follow what you said... http://fsae.com/groupee_common/emoticons/icon_smile.gif

[RaceCatt69]

Originally posted by SteveHarasym:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RaceCatt69:
start by stopping. suspension on an FSAE car is not a necessity. put your efforts elsewhere, but dont put them all in one basket as they say

You, sir, should also read the rules and/or stop giving blatantly wrong advice. It is necessary to have a suspension. See T6.1.1 </div></BLOCKQUOTE>

yes, I should have worded differently. I meant it is not necessary to put a lot of effort into suspension design.

[Racer-X]

Originally posted by RaceCatt69:
yes, I should have worded differently. I meant it is not necessary to put a lot of effort into suspension design.

On our courses yes it is, this isn't the local drags.

[Abhilash Saksena]

hi again... m facing a prblm with my front suspension... i minimised the roll centre movement ... but as per the animation generated by lotus... the dampers and springs are not moving in a straight line but change their angle with respect to their axis and their fronts move closer to each other(i am using double wishbone pushrod to damper for front...) also... the lower A arms are like just 100mm apart and the upper ones are 200mm apart... such distances are permissible right?

[PatClarke]

Abhilash,
If you posted some pictures, we might have a better idea of your issues.

Pat

[94vishu24]

Abhilash,
If you didn't know where to start, how did you start analyzing??
The analyzer won't help you much if you haven't researched. Right now you should probably pic up a few vehicle dynamics books and try and understand about tires,then proceed to the geometry.
try figuring out things yourself about Why we do this and its effect and whatever

also if you don't understand the book, don't worry. Switch to another one. Then come back to the first one and try reading the part you didn't understand again.

start with a paper written by Adam Theander to get familiar with the basics
try Carrol Smith books
then if you start understanding things extremely well, try reading RCVD(thats a bit advanced)

also, Complete car suspension is also a highly recommended book


get your hands on some tire data. try to understand it.

this much should keep you busy for quite a lot of time

[SteveHarasym]

Abhilash,

As Pat said, pictures would help us better understand your question. Although in general, having the "damper axis" change direction is not a problem. Need pictures to help out more though.

[Warpspeed]

Spring/damper axis by itself is not really that important.
What DOES matter is the amount of spring/damper compression and extension versus vertical wheel motion.
Many moving suspension points are going to travel in arcs, so a lot of angles are going to change with vertical wheel travel, including the axis of the spring/damper.

[Z]

Originally posted by Abhilash Saksena:
... i minimised the roll centre movement ....
Abhilash,

Why do you want to "minimise roll centre movement"? http://fsae.com/groupee_common/emoticons/icon_confused.gif

Some people say it is NOT a problem. Where, or from whom, did you hear that it should be minimised???

Z