centre of gravity height

[clausen]

Hi all,

Does anyone know the rough average centre of gravity height of these cars? Just need a reasonably accurate number for some initial calcs. Would like to measure it, but dont have a car available to do so.

Thanks,

Regards

Paul Clausen
Uni of Adelaide

[clausen]

Hi all,

Does anyone know the rough average centre of gravity height of these cars? Just need a reasonably accurate number for some initial calcs. Would like to measure it, but dont have a car available to do so.

Thanks,

Regards

Paul Clausen
Uni of Adelaide

[ben]

I'd say about 0.3 of a metre above the ground would be a good start. Maybe fractionally lower?

Ben

University of Birmingham
www.ubracing.co.uk (http://www.ubracing.co.uk)

[gug]

have a look at uni queensland's specs (http://www.uq.edu.au/fsae/2002techspecs.htm). quite detailed, really useful.

edit: hi Paul! should probably just tell you about this at uni hey? oh well. http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

- if it isnt coming, you need a bigger tool.

[BeaverGuy]

You should try and calculate what the maximum CG height should be so as to pass the tilt table test. ex. if the car is 4 ft wide with the CG centered latterally and the table is at 60 degreees the max height for the CG would bejust under 14 inches.

I believe our CG is around 10 inches off the ground with driver but I'm not absolutely sure.

[Denny Trimble]

From what I've heard, the range is between 9 (UMC?) and 12 inches above ground, with driver.

The lateral tilt method is much more reliable than the "jack up the front wheels" method, if you're looking to measure your CG height. Running dummy shocks might be a good idea here too.

University of Washington Formula SAE ('98, '99, '03)

[Frank]

just a few questions and points

the CG of the engine.. 1 1/2 inches above the crankshaft?

the cg of the driver... bellybutton?

cg of unsprung mass... axle height? 10.5 inches?

cg of the rest of the car below 10 inches.. hmmm.. maybe

cg of car and driver wet and ready to drive....?

according to some teams.. below the axle...

where's my goat?

[buggaero]

I tried finding the Center of Gravity height for our vehicle with the following method of raising :

CGH= WB x FWc / TW x Tan of angle


Center of Gravity Height Formula


Definition of Variables

CGH - Center of Gravity Height
WB - Wheelbase (inches)
TW - Total weight
FW1 - Front weight LEVEL
FW2 - Front weight RAISED
FWc - FW2 - FW1 (change in weights)
HT - Height raised (inches)
Adj - Adjacent side (see below)
Tan q - Tangent of angle (see below)
CLF - Left Front tire circumference
CRF - Right Front tire circumference
C - (CLF + CRF) / 2 (average circumference)
r - Axle Height

My values
Wheelbase (inches) : 65.73

Total Weight (lbs) : 597.452

Front Wheel Weight - Level (lbs ) : 99.205 (single tyre)

Front Wheel Weight - Raised (lbs ) : 156.386

Raised Height (inches) - 10

Left Front Tire Size (circumference in inches): 62.94

Right Front Tire Size (circumference in inches) : 62.94


RESULTS I'M GETTING
Center of Gravity Height from Axle Height: 40.86"
Center of Gravity Height from Ground : 50.88"


Not able to find a solution to this, plus i feel like ground clearance should play a role in CoG determination.

[buggaero]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by buggaero:
I tried finding the Center of Gravity height for our vehicle with the following method of raising :

CGH= WB x FWc / TW x Tan of angle


Center of Gravity Height Formula


Definition of Variables

CGH - Center of Gravity Height
WB - Wheelbase (inches)
TW - Total weight
FW1 - Front weight LEVEL
FW2 - Front weight RAISED
FWc - FW2 - FW1 (change in weights)
HT - Height raised (inches)
Adj - Adjacent side (see below)
Tan q - Tangent of angle (see below)
CLF - Left Front tire circumference
CRF - Right Front tire circumference
C - (CLF + CRF) / 2 (average circumference)
r - Axle Height

My values
Wheelbase (inches) : 65.73

Total Weight (lbs) : 597.452

Front Wheel Weight - Level (lbs ) : 99.205 (single tyre)

Front Wheel Weight - Raised (lbs ) : 156.386

Raised Height (inches) - 10

Left Front Tire Size (circumference in inches): 62.94

Right Front Tire Size (circumference in inches) : 62.94


RESULTS I'M GETTING
Center of Gravity Height from Axle Height: 40.86"
Center of Gravity Height from Ground : 50.88"


Not able to find a solution to this, plus i feel like ground clearance should play a role in CoG determination. </div></BLOCKQUOTE>


Problem Solved.
Weight transfer calculation error. It's just 2.395lbs per front tire.