Quote:
Originally Posted by stealth
Joe of Loath - I always have wondered what's it like to drive one of those, I raced closely against one with same design but in carbon fibre at the final of 2013 and it looked good, is it slightly more unstable in the corners or does it not matter too much? Also did you ever use or experiment with derailleur gearing?
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Which one, the F24+ or the F24 with the outrigger?
The F24+ car handled great, it had single wishbone front suspension with rubber engine mounts as dampers, barely 2cm of travel but enough so that when you steered into a corner the body roll would increase the camber and lower the centre of gravity. At Goodwood and Castle Coombe I never had to brake, just lift off for the chicanes. Picture:
https://lh3.googleusercontent.com/-u...2/IMG_1809.JPG
The F24 car handled OK, it understeered and scrubbed tyres but that may have been due to the ackermann of the recumbent trike hubs we were using. It was never unstable due to being so damn wide!
We used derailleur gearing on our previous car, but it was too complicated for the younger, less experienced drivers. You need to have a hawk eye on your power consumption and shift up and down according, and the younger drivers would forget and power round the track as fast as possible, sucking all the juice from the batteries. The F24 cars remained single speed after the first couple of years - even for the national podiums. With good driver training they tend not to slow down so much, so gears aren't as vital. We had a rubber bump clutch type mechanism to stop us from snapping chains.
The F24+ car had a 9 speed transmission I believe, and with the two of us more experienced drivers racing we could drive it to suit pretty much any power budget. That was actually the inspiration for my final university project (an automatic transmission for bicycles) but that's a story for another day.
EDIT: I see some roll bar and camber talk. Our roll bar was faired with pieces of wooden edging strip (basically a dowel cut in half) and pieces of 1mm aluminium bent and taped into place around the square box section. It gives you a great aerodynamic cross section with virtually zero weight penalty. Eventually though we built a full fairing, with the (perhaps fanciful) idea that any wind other than a headwind would give us some forwards momentum.
RE camber, back in the early days (~2004 ish) lots of cars had problems with wheels folding in corners. Because bicycle wheels work best with a vertical load, camber helps to keep the load vertical (in relation to the wheel hub) through corners. It also reduces tyre deflection.
FWIW we used Schwalbe Marathons in 16" on all our cars.