Quite interested by your earlier post Simon, I took a couple of measurements from my Tonykart Viper (that's a TKM rather than Rotax) to see just how well the engine and seat offsets counterbalanced one another.
The engine Cog is 260 mm from the centreline, and the engine weighs 14.5 kg, giving a moment about the centreline of 3.77 kg.m. The seat on my one is offset 20 mm to the other side of the centreline (and I've never moved the right-hand seat mount, only the left one, so it's less offset than it can be). I weigh about 70 kg, and carry 6 kg of lead on the seat, so in full race suit I reckon me and the seat are about 80 kg, giving a counter moment of 1.6 kg.m. Total moment is therefore about 2.2 kg.m.
Running somewhere around maximum rear width most of the time, this equates to a difference in side to side corner weights of 1.85 kg, a little over 1% of the kart's race weight. I was quite surprised by this, as it's well over double the difference I measured when I was messing with corner weights on my old karts a couple of years back.
I'm not sure how much difference this makes in the greater scheme of things, but I know 20 mm of fore-aft seat movement makes a really big difference. Ever the keen experimenter I'm going to move the seat mounts over to the left a bit when I replace the "swiss cheese" seat that I've been using to find a setup with the Tonykart. Thanks for the useful post - it made me think about this again...
Liam
|
|
