Suspension, try to make a setup like the rear triangle of this bike, 2 carbon tubes and a pivoting point. Setup can be done by changing the joints with different torsion.
Thank you really doesn't really describe enough what I feel. - Vettel
The easiest way to achieve 1bhp/lb would be to buy a small hillclimb car with a V8 in the back. On the plus side, when it all goes wrong, it's pretty strong...
Greg Locock wrote:It is very hard to reduce the mass of an existing design, it is far simpler to start with one that is too light and carefully add all the essential features, including perhaps an uprated spaceframe.
You need a weight budget, a piecemeal approach will just result in endless handwaving.
Given that your unsprung mass alone is likely to total 160 kg, I think you have a bit of a challenge to meet your 380 kg target.
Unsprung mass per corner
tire 11kg
wheel 4 kg
hub, wheel nuts 1 kg
CV joint 2 kg
brake disc 2kg
calliper 1kg
half of halfshaft, suspension arms, spring, shock 6kg
upright 2 kg
that's 29kg per corner with wheels that'll last 5 seconds.
A weight budget is the right way forwards to achieving your goals. Know what's heavy and you can know how to make it lighter. However, I'd say there's a lot to strip out of the weights above. My wheel/tyre combo is about 10kg (9"x13" magnesium rims and Avon radials), so there's 5 kg saved. It's amazing how lightweight things can be made - look at the rear end of this car. The whole Empire Wraith weighs between 250-300kg and it's not the lightest car on the track. The wishbones can be bent by hand...
Let's just have a look at Andy's car, to see why this is a bit of a daft way to go about it. He's running 13" rims, so his brakes are necessarily 260mm in diameter or so, unless he's running inboards, which is a weight increase in itself. Now, the chances are that at PP bigger brakes are worth having, so using 15" wheels might offer a performance benefit DESPITE being heavier.
So you not only need a weight budget, you need some idea of the regime in which the vehicle is operating, and the effect on avergae speed.
That's a really, really good point. The events I run at are usually measured in yards rather than miles, so the brakes barely get up to temperature. Of course, going uphill in a light car with lots of downforce (drag) minimises the braking power needed. That's why some of the cars run tiny brakes from motorbikes.
