Strange that eh!.
I finally got round to getting my car weighed today, at my local weighbridge - I've been driving it for over a year and a half!
Considering that it's a standard chassis with a car engine, steel floor, and no special effort to keep it light, I was very pleased that it came
out at 600kg ( +/- 20kg) with a half-tank of petrol.
David.
What was the axle weight at SVA ? , does that not relate to the total weight?
quote:
Originally posted by Surrey Dave
What was the axle weight at SVA ? , does that not relate to the total weight?
Bloody strange that, had my MK Blade on the scales today too. 500 kg +/- 20kg, full tank of fuel.
Strange that eh!.
quote:
Originally posted by iank
I think if you could figure out the exact COG of the car you could theoretically work it out with lots of trig and simultaneous equations, but practically speaking it's far easier to go the the weighbridge.
600kg sounds a good weight for a CEC.
quote:
Originally posted by flak monkey
quote:
Originally posted by iank
I think if you could figure out the exact COG of the car you could theoretically work it out with lots of trig and simultaneous equations, but practically speaking it's far easier to go the the weighbridge.
600kg sounds a good weight for a CEC.
All you need is the location of the CoG between the axles. Then its just moments. Pretty simple stuff, but most people wont know where the CoG lies.
Weights are around what I would expect, some of the weights quoted recently in another thread worried me somewhat!
Adding the axle weights should give the total car weight unless they were not measured properly (e.g. car not perfectly horizontal when measured).
The total of the axle weights will give all up weight. from the two axle weights you can calculate the CofG easily (longitudinaly anyway). If you want lateral Cofg you need the weights at all 4 wheels.
to calculate CofG just remember
Wt =W2+W1
measuring from W1 you ignore the weight at W1....
therefore
a x WT = (a + b) x W2
as you know what a+b equals and what Wt, and W2 are you can solve for a and thus b as well....
Description
Total of the weights at SVA will give you a weight less than that of the whole car. i believe they are measured seperately so...
The car can be modelled as a beam. The CoG being the load, one axle being a pivot point, the other being the force measurement point.
The load is not directly above the point where the force measurement is being taken so moments come in to play, which as far as i can see will always
reduce the total weight of the car.
Theres a bit about it in the SVA manual IIRC laid out slightly differently though.
Of course if both axle weights are measured at the same time then the total weight is that of the car.
So how does the axle weighing machine know whether the other end of the car is on a set of scales or not?
Actually it doesnt make the slightest bit of bloody difference does it? The sum of the reaction forces at each wheel will always equal the total
weight of the car.
Jeez you can tell I havent done any real maths for 2 years.
quote:
Originally posted by welderman
Bloody strange that, had my MK Blade on the scales today too. 500 kg +/- 20kg, full tank of fuel.
Strange that eh!.
quote:
Originally posted by David Jenkins
quote:
Originally posted by welderman
Bloody strange that, had my MK Blade on the scales today too. 500 kg +/- 20kg, full tank of fuel.
Strange that eh!.
When I typed my meggase I just KNEW that some BEC builder would under-cut me by a mile!
I don't care... I'm happy with my result!
BTW: At my SVA the design weight was listed as 800kg on the forms - 350kg axle 1, 450kg axle 2.
David
quote:
Originally posted by flak monkey
Actually it doesnt make the slightest bit of bloody difference does it? The sum of the reaction forces at each wheel will always equal the total weight of the car.
Jeez you can tell I havent done any real maths for 2 years.
if it isnt on a perfect level then the 2 axle weights if measured on the same scales (ie measure front the turn the car round and measure the back) wont add up to the total weight but it would have to be seriously of level to make any real difference (ie enough to be out of the +-20kg)
quote:
Originally posted by welderman
No offence there, i meant that it was strange we both had ours done.
