My racing sport of choice is gravity racing. Each year, there's a race in Canada that basically features the mother of all hills - with an 18% grade for the final drop. It's mental. This year this car did 101mph, a new world record.
Basically, i'm trying to work out how this car can be beaten. It's got about as small a frontal area as possible for a human to fit into, is the max length allowed, and is always ballasted up to the max weight allowance. The tyres are essentially a tried and tested narrow "kart" style tyre, known to be safe at such speeds. As you can imagine, stability is key.
So with all that in mind, as far as I can see (CFD modelling of the body aside, which to my knowledge they didnt do) the only area that could perhaps be improved on is the underbody.
So that leads me to my question: On a car with no engine and no requirement for any real downforce, what effect does the flat underbody and low ride height that this car and others like it have on drag? Is this an area for substantial improvement, or have they got it pretty much right?