Roll Center
03-03-06, 04:06 PM
#1
Senior Member
Thread Starter
iTrader: (2)
Join Date: Oct 2001
Location: West Los Angeles
Posts: 377
Likes: 0
Received 0 Likes
on
0 Posts
Roll Center
Does anyone know what the height of the roll center and c.g. of 88 TII are?
Does anyone have the suspension points as well if they are willing to share?
Does anyone have the suspension points as well if they are willing to share?
03-03-06, 04:47 PM
#2
I don't have a very exact drawing to go off of, so this take this as just a pure guesstimate.
It appears the static roll center for the front is just below the undertray. So, that's about 4" off the ground. I found some info in the Yamaguchi book that I can use to calculate the static rear roll center, but again, it's just going to be an estimate. Give me a few minutes on that one.
As far as CG location, I don't know the height, but if you want to have some fun, try this link!
http://www.racerpartswholesale.com/longtech6.htm
It appears the static roll center for the front is just below the undertray. So, that's about 4" off the ground. I found some info in the Yamaguchi book that I can use to calculate the static rear roll center, but again, it's just going to be an estimate. Give me a few minutes on that one.
As far as CG location, I don't know the height, but if you want to have some fun, try this link!
http://www.racerpartswholesale.com/longtech6.htm
03-03-06, 04:51 PM
#3
Powered By Trochoids
Join Date: Oct 2004
Location: Philly | PA
Posts: 1,457
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by JerryLH3
I don't have a very exact drawing to go off of, so this take this as just a pure guesstimate.
It appears the static roll center for the front is just below the undertray. So, that's about 4" off the ground. I found some info in the Yamaguchi book that I can use to calculate the static rear roll center, but again, it's just going to be an estimate. Give me a few minutes on that one.
As far as CG location, I don't know the height, but if you want to have some fun, try this link!
http://www.racerpartswholesale.com/longtech6.htm
It appears the static roll center for the front is just below the undertray. So, that's about 4" off the ground. I found some info in the Yamaguchi book that I can use to calculate the static rear roll center, but again, it's just going to be an estimate. Give me a few minutes on that one.
As far as CG location, I don't know the height, but if you want to have some fun, try this link!
http://www.racerpartswholesale.com/longtech6.htm
03-03-06, 05:03 PM
#4
It's coming along. 
We submitted the design report, specs and impact attenuator data with a couple of minutes to spare Wednesday night. Then I was starving, so I went for some food. Didn't get too bed until 3 AM Thursday morning. The frame is done, suspension is coming along, and the engine is on the dyno. It'll be rolling soon. It'll probably be a mad scramble towards the end, but I think we'll have some dedent testing time as opposed to last year, when there was none. This is only our second effort, so these things take time. I imagine VT is close or already testing. 
I also see that formula geeks like us are attracted to threads with the word "roll center" in them. Speaking of which, I'm going to have to go outside and take some rough measurements if I want an approximation of the rear roll center. It's not easy calculating things from someone else's design.
We submitted the design report, specs and impact attenuator data with a couple of minutes to spare Wednesday night. Then I was starving, so I went for some food. Didn't get too bed until 3 AM Thursday morning. The frame is done, suspension is coming along, and the engine is on the dyno. It'll be rolling soon. It'll probably be a mad scramble towards the end, but I think we'll have some dedent testing time as opposed to last year, when there was none. This is only our second effort, so these things take time. I imagine VT is close or already testing. I also see that formula geeks like us are attracted to threads with the word "roll center" in them. Speaking of which, I'm going to have to go outside and take some rough measurements if I want an approximation of the rear roll center. It's not easy calculating things from someone else's design.
03-03-06, 05:06 PM
#5
Powered By Trochoids
Join Date: Oct 2004
Location: Philly | PA
Posts: 1,457
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by JerryLH3
It's coming along. We submitted the design report, specs and impact attenuator data with a couple of minutes to spare Wednesday night. Then I was starving, so I went for some food. Didn't get too bed until 3 AM Thursday morning. The frame is done, suspension is coming along, and the engine is on the dyno. It'll be rolling soon. It'll probably be a mad scramble towards the end, but I think we'll have some dedent testing time as opposed to last year, when there was none. This is only our second effort, so these things take time. I imagine VT is close or already testing.
I also see that formula geeks like us are attracted to threads with the word "roll center" in them. Speaking of which, I'm going to have to go outside and take some rough measurements if I want an approximation of the rear roll center. It's not easy calculating things from someone else's design.
We submitted the design report, specs and impact attenuator data with a couple of minutes to spare Wednesday night. Then I was starving, so I went for some food. Didn't get too bed until 3 AM Thursday morning. The frame is done, suspension is coming along, and the engine is on the dyno. It'll be rolling soon. It'll probably be a mad scramble towards the end, but I think we'll have some dedent testing time as opposed to last year, when there was none. This is only our second effort, so these things take time. I imagine VT is close or already testing. I also see that formula geeks like us are attracted to threads with the word "roll center" in them. Speaking of which, I'm going to have to go outside and take some rough measurements if I want an approximation of the rear roll center. It's not easy calculating things from someone else's design.
03-03-06, 05:15 PM
#6
So, the car you use for this year's competition is done, and you're working on next year's? Or you guys build two each year? Either way, I wish we had that kind of organization.
And it appears the rear static roll center is about 4.75" off the ground. But seeing as how I took measurements with a tape measure in the driveway, don't put too much faith in those numbers.
And it appears the rear static roll center is about 4.75" off the ground. But seeing as how I took measurements with a tape measure in the driveway, don't put too much faith in those numbers.
03-03-06, 05:16 PM
#7
Must be nice, when I was doing that project in college my team wasn't able to test properly test before the comp. Developed it after Michigan and dropped 15 seconds at a 1:30 test track we had access to. Good luck guys, it's a frustrating experience, but you become a better engineer because of it.
Peace
Peace
Trending Topics
03-03-06, 05:24 PM
#8
Powered By Trochoids
Join Date: Oct 2004
Location: Philly | PA
Posts: 1,457
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by JerryLH3
So, the car you use for this year's competition is done, and you're working on next year's? Or you guys build two each year? Either way, I wish we had that kind of organization.
And it appears the rear static roll center is about 4.75" off the ground. But seeing as how I took measurements with a tape measure in the driveway, don't put too much faith in those numbers.
And it appears the rear static roll center is about 4.75" off the ground. But seeing as how I took measurements with a tape measure in the driveway, don't put too much faith in those numbers.
03-03-06, 05:28 PM
#10
Wow, that's so cool. Like I said, I wish we had that kind of time, manpower and money. I'll be glad to see this car finished. It's a much smaller car than last year's design and will weigh quite a bit less too.
It's frustrating, it's hard work, it takes time away that I could use to study or have/keep a girlfriend, but I certainly wouldn't give it up, because in the end, it still puts a huge smile on my face.
It's frustrating, it's hard work, it takes time away that I could use to study or have/keep a girlfriend, but I certainly wouldn't give it up, because in the end, it still puts a huge smile on my face.
03-03-06, 05:33 PM
#11
Powered By Trochoids
Join Date: Oct 2004
Location: Philly | PA
Posts: 1,457
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by JerryLH3
Wow, that's so cool. Like I said, I wish we had that kind of time, manpower and money. I'll be glad to see this car finished. It's a much smaller car than last year's design and will weigh quite a bit less too.
It's frustrating, it's hard work, it takes time away that I could use to study or have/keep a girlfriend, but I certainly wouldn't give it up, because in the end, it still puts a huge smile on my face.
It's frustrating, it's hard work, it takes time away that I could use to study or have/keep a girlfriend, but I certainly wouldn't give it up, because in the end, it still puts a huge smile on my face.
03-03-06, 09:38 PM
#13
Senior Member
Thread Starter
iTrader: (2)
Join Date: Oct 2001
Location: West Los Angeles
Posts: 377
Likes: 0
Received 0 Likes
on
0 Posts
Yes I too was on a FSAE team, at UNM in 2004, suprised to see they did very well in 2005 with the platform we left them to go from they got 12th place last year!
I am at CSU right now getting a masters in motorsport engineering, sounds good, but if you head that way GO TO ANOTHER SCHOOL, they barely can get an FSAE car together and their graduate program is a joke, no funding, no real race contacts except for one student who hasn't even been given funding to pay for tuition, he is basically the heart of the program and receives jack for it... sorry about ranting...anyway
Yeah I was just seeing if anyone had that data so that I didn't have to go do the measurments myself, so thanks for taking some measurements, I will probably get under there and get the suspension points and arm lengths and build a 3D model to figure out all the info and I'm also curious about the roll center variation too, then I will share it, its good info to have for anyone who is making some educated suspension decisions for their car, especially with the macpherson front. I am looking at buying some coil overs since I just won a lawsuit and have about $2500 to spend on the car, the body was damaged but I don't care I want better stuff under the body. So I was figuring out what the front roll transfer distribution is with the STANCE coil overs, they are a good deal and come with camber plates too, but the spring stiffness is super high. 9k/7k, so I was seeing what those rates do with the weight transfer and distribution to see what size anti-roll and what adjustability might be needed for fine tuning, and what I can do with some lower spring rates as well.
Just a note:
That longacre method though is about as accurate as guesstimating for the C.G. height, if you are off by just a small amount you will miss it by about 3 inches or more. The best way is to lift the car up sideways all the way until it balances on the corner of the tires (best to put L iron under the tire edges), yes up like 75 degrees, then you can be off by a few degrees and the percentage of error is only around 1 percent. I say its probably about 25" inches, about half the height of the car, maybe a little lower than that.
I am at CSU right now getting a masters in motorsport engineering, sounds good, but if you head that way GO TO ANOTHER SCHOOL, they barely can get an FSAE car together and their graduate program is a joke, no funding, no real race contacts except for one student who hasn't even been given funding to pay for tuition, he is basically the heart of the program and receives jack for it... sorry about ranting...anyway
Yeah I was just seeing if anyone had that data so that I didn't have to go do the measurments myself, so thanks for taking some measurements, I will probably get under there and get the suspension points and arm lengths and build a 3D model to figure out all the info and I'm also curious about the roll center variation too, then I will share it, its good info to have for anyone who is making some educated suspension decisions for their car, especially with the macpherson front. I am looking at buying some coil overs since I just won a lawsuit and have about $2500 to spend on the car, the body was damaged but I don't care I want better stuff under the body. So I was figuring out what the front roll transfer distribution is with the STANCE coil overs, they are a good deal and come with camber plates too, but the spring stiffness is super high. 9k/7k, so I was seeing what those rates do with the weight transfer and distribution to see what size anti-roll and what adjustability might be needed for fine tuning, and what I can do with some lower spring rates as well.
Just a note:
That longacre method though is about as accurate as guesstimating for the C.G. height, if you are off by just a small amount you will miss it by about 3 inches or more. The best way is to lift the car up sideways all the way until it balances on the corner of the tires (best to put L iron under the tire edges), yes up like 75 degrees, then you can be off by a few degrees and the percentage of error is only around 1 percent. I say its probably about 25" inches, about half the height of the car, maybe a little lower than that.
03-03-06, 10:12 PM
#15
Ah, well, if you were on an FSAE team, you probably know a thing or two about roll centers. And looking back at it, I goofed on the rear roll center. It's on page 636-7 of Race Car Vehicle Dynamics by Milliken if you want to take a look. I misinterpreted the diagram to find the IC. In which case, you're better off taking your own measurements.
I'll blame it on the fact I've never found the roll center for a semi-trailing arm before.
I'll blame it on the fact I've never found the roll center for a semi-trailing arm before.
03-03-06, 10:21 PM
#16
Powered By Trochoids
Join Date: Oct 2004
Location: Philly | PA
Posts: 1,457
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by JerryLH3
Ah, well, if you were on an FSAE team, you probably know a thing or two about roll centers. And looking back at it, I goofed on the rear roll center. It's on page 636-7 of Race Car Vehicle Dynamics by Milliken if you want to take a look. I misinterpreted the diagram to find the IC. In which case, you're better off taking your own measurements.
I'll blame it on the fact I've never found the roll center for a semi-trailing arm before.
I'll blame it on the fact I've never found the roll center for a semi-trailing arm before.
03-03-06, 10:36 PM
#17
Actually, I was talking about "kleetuz".
I too have a shelf full of books - RCVD, the To Win Series, and Racing Chassis and Suspension Design, which was also put together by Smith. It's full of a bunch of SAE papers. Some are good and very relevant (Modeling Steady-State Suspension Kinematics and Vehicle Dynamics of Road Racing Cars) and some are not (The Effects of Local Spring Perch Flexibility on Suspension Geometry of a Winston Cup Race Car).
I too have a shelf full of books - RCVD, the To Win Series, and Racing Chassis and Suspension Design, which was also put together by Smith. It's full of a bunch of SAE papers. Some are good and very relevant (Modeling Steady-State Suspension Kinematics and Vehicle Dynamics of Road Racing Cars) and some are not (The Effects of Local Spring Perch Flexibility on Suspension Geometry of a Winston Cup Race Car).
03-04-06, 01:30 AM
#18
Senior Member
Thread Starter
iTrader: (2)
Join Date: Oct 2001
Location: West Los Angeles
Posts: 377
Likes: 0
Received 0 Likes
on
0 Posts
I would recommend looking at Clemson, from what I've heard their program is many, many years ahead of CSU's and they have a lot more research going on and partnerships with many company's, bmw and some nascar teams. The program here actually only has two classes dealing with motorsports, they were vehicle dynamics and race car vehicle dynamics, which were great, the other classes are all just generic and could have an application to motorsports, just the same as a machine component design course has motorsport application. Milliken is a good book, but it kind of glosses over transient vechicle response and mentions many ideas and concerns but doesn't quite address them directly, but it still is the bible of race car design and concepts a great place to get direction if you aren't quite sure of something.
If you have a chance definitely take the Optimum G seminar by Claude Rouelle, he is such a smart engineer and provides a great lecture providing many ideas and concepts and more importantly the application of these in race car setup and design considerations. I know he usually has a seminar near the time of the FSAE competition when it was in Detroit, but I don't know how or where it will be with the new bi-coastal setup. Might check out www.optimumg.com. We were lucky enough to get a seminar comped by the graduate program, it is pretty expensive, but I would say more than worth it.
If you have a chance definitely take the Optimum G seminar by Claude Rouelle, he is such a smart engineer and provides a great lecture providing many ideas and concepts and more importantly the application of these in race car setup and design considerations. I know he usually has a seminar near the time of the FSAE competition when it was in Detroit, but I don't know how or where it will be with the new bi-coastal setup. Might check out www.optimumg.com. We were lucky enough to get a seminar comped by the graduate program, it is pretty expensive, but I would say more than worth it.
03-04-06, 06:39 PM
#19
He's doing seminars after both of the competitions, but I don't think my schedule will allow it. I'm actually planning on going when he does one in the fall. I figure why not fly out to Colorado for a weekend? It'd be a good excuse to get away.
And he gives Formula SAE students quite a deal, so it's pretty affordable.
I'm not pretending to know where I'll go after finishing my undergrad, but if motorsports is calling, I'll sure be answering.
And he gives Formula SAE students quite a deal, so it's pretty affordable.
I'm not pretending to know where I'll go after finishing my undergrad, but if motorsports is calling, I'll sure be answering.
03-04-06, 08:10 PM
#21
As far as I know, Clemson and Coloroda State are the only ones. Unless of course, you travel overseas to the UK, where you can do undergrad and master's level degrees with motorsports themes.
But after a quick Google search: http://www.motorsportsemployment.com..._colleges.html
But after a quick Google search: http://www.motorsportsemployment.com..._colleges.html