This seems to be the best place to ask this question...
Does anyone know of a reason for SCCA, and likely other sanctioning bodies, requiring that the continuous roll cage hoop(s) be lateral/transverse, rather than running fore & aft on each side of the car.
From the SCCA GCR - "The main hoop (behind the driver) must be the full width of the cockpit for all cars."
This leads to a roll cage design that looks something like this:
Attachment:
FPSevenLateralRollHoop.jpg
For larger cars this can work just fine, but for smaller cars, like a locost or similar car, this design requirement of having lateral continuous hoops tends to lead to more bends in tubes in order to keep the fore & aft "above the window" bars far enough from the occupant('s) heads. In the picture above you can see the inward bends in those above-window bars just before they meet the main roll hoop in the cage. Those bends are necessary to keep the fore & aft above-window bars far enough from helmeted heads.
For a small car I see only structural, safety, and appearance advantages to a design that has two fore & aft continuous side hoops (A-pillar, then "above-window", then "rear brace" all in one tube, with one on each side of the car, with straight cross members "above-windshield", and behind&above-driver, and at-dash, and for-shoulder-harnesses, with two near vertical straight bars to form the sides of what would formerly be the main hoop, like this one:
Attachment:
SprintCarForeAftRollHoops.JPG
This design keeps all the tubes easily away from the occupant's head, without adding extra bends or raising the overall height. I am thinking of going on a letter writing campaign to SCCA first, to request that having the continuous hoops run fore and aft, on each side of the occupants, rather than transverse behind and in front of the occupants. If adding a cage within a closed production car body, the continuous hoops being fore-aft on each side of the car likely makes it easier to tuck all the cage tubes close to the body and further from the driver's head, so the design advantages of a change may apply more broadly than to just small cars.
Continuous transverse hoops seem to me to be a tradition-driven requirement, rather than a structural or safety driven requirement..?
Am I missing something here?
If a visual of this cage design applied to a locost type of frame would help, I can model in in Solidworks when I can get some time.
Dean