Zyzyxxz said:
nice, but I personally I would start off with fiberglass first since its cheaper and you wont know how much it really helps without real life data and to spend that much on a CF diffusor to find out it can be improved would be costly.
Though you probably know a bit more about aerodynamics than I, I have never seen a book of it even :lol
We do our own work (my father taught me composites when I was 10 so that I could help fund our racing), so for us the downside is really the time it takes for carbon vs glass moreso than the cost. We're not using prepregs, just wet layup w/ vacuum bagging. I'd prefer to go with carbon for stiffness on this part. As long as I'm 20lbs overwieght I'm not going to get caught up in the marginal weight savings.
As far as optimization goes, that should be interesting. These cars were designed decades ago with no regards for underbody aero. There's not even a floor from the roll bar back, just an open engine bay. Rear diffuser design is going to be driven by where we
can put things, not really where we'd like to. I came up with a pretty novel way to move the rear springs / shocks inboard, so that'll help, but it's still pretty messy back there.
I've still though about writing advantageCFD with a poverty story and seeing if they'll sponsor us with a non-commercial license - I've done solid modelling and FEA and I've got my masters in mechanical engineering so I'm confident I could learn CFD. Maybe they'd think a young guy using their software to modernize a car that's older than him is novel enough to give away a seat.
I'm actually very excited about the front diffuser as well. These cars have a locked rear end so they tend to understeer. My father has always been reluctant to work on rear downforce because of this. There's a ton of room up front to do a large, stiff splitter with diffusers, and I'm thinking that some front dive planes for tuning would get the front to grab. Of course an LSD would solve the actual root cause, but those are big money - maybe later.
Well, I've completely digressed, so sorry to the other posters. If you're interested in competition car aero, I can send you a PM with a couple of good, practical books and a link to a site with some amazing shots of sports cars (WSC, IMSA, ALMS, etc) and their aero.
EDIT: Here's a pic to the rear of the car with the bodywork off. The bottom is open underneath here, I can't imagine the wake he's leaving behind the car because of that. GSX-R 1000 engine in case you're wondering, cars weight between 900-1000lbs with driver and fluids.
http://sports.racer.net/images/chassis/legrand/chip_haddock/sebring_090101_6.jpg
(On sale $14.99 at Fry's).
