Hey there, veteran F24 and F24+ racer (and national podium winner) here, so I should be able to give some insight. Our team gallery is here if you want to see some more photos, including construction galleries.
https://picasaweb.google.com/thepodmovement/
Our F24+ car. I understand the rules have changed somewhat from when we raced, but it should give some inspiration. The batteries lived behind those removable front wheel panels.
Our (slightly left field) F24 car, designed as such because I was too tall to fit in a car with the batteries in a somewhat aerodynamic place, so we put them outboard to halve the frontal area vs putting one either side. I ended up outgrowing this car too and getting a pass to move on to F24+ early (I was the reason F24+ cars are allowed to be longer, heh).
The chassis design for both is semi-monocoque. Welded steel frame (old school tables with the chewing gum peeled off) with components bolted to it, but not strong enough to support the car on its own. The rest of the strength is provided by bamboo and plywood, held together with fiberglass. Incredibly stiff, and I actually completely wrote off (accidentally! They cut me up) a honeycomb aluminium and carbon fibre F24+ car in the F24 car (for a while we raced it in both formulae) with barely a scratch.
Note the design cues: an upwards taper on the rear end and high ground clearance: we wanted to get as much of the car way from turbulent air near the ground as possible. We also used cheap and available materials; steel, bamboo, plywood, household filler. In our minds the expense of high end composites, TIG welded aluminium (which we would have had to have outsourced - not our M.O) weren't worth it, we thought we could (and did) beat teams which depended on expensive materials through better design and driving. Seriously, driver training is a huge factor. Did you know that you don't have to brake into the chicane at Goodwood?
Any more specific questions feel free to ask, now that I'm not involved any more I'm happy to share trade secrets with other teams
