As a car builder that rents several cars several times a year, I study the rules quite alot and field cars in SCCA and NASA.
The nasa cage rules seem like a stone copy of circa 2004 SCCA cage rules. SCCA has evolved the cage rules and fixed some things that have popped up over time, and their newest 2014 ruleset reduces some problems that Spec Miata cars have.
Is NASA going to keep this parallel?
OR, if I have a SCCA logbook and annual tech, does that "bonified sanctioning body" document trigger the same from NASA? (CCR 16.0 "Safety inspection" seems to indicate this)
Pertaining to Spec Miata, here are my main 2 issues, (although I have found a half dozen conflicts).
We lost a car at the 25 hour this year. The physics of the crash were just brutal and there are things to learn from it. The driver was helicoptered out and is expected to recover fully, but got damn lucky on a whole myriad of safety points. As the car owner it really makes you think. If any of the taller drivers on the team were in the accident I believe it would have been even more serious than it was, much more so.
Miatas just don't have enough head room, and is a constraint we all have to deal with. The SCCA rules allow me to make a little more headroom in the cage. Specifically, the main hoop diagonal bracing can either be in the plane of the rear braces, or only be required to go 50% across the main hoop. NASA requires this brace to be in the main plane of the hoop, and be within 12" of the drivers side upper corner.
This puts it in reach of impact with the drivers head much sooner than the other designs. In fact with tall drivers, you are driving with your head touching this bar, or nearly so. In the case of the miata, with such a short "box" as defined by the main hoop, the point of the full diagonal bracing gets outweighed by increased head room, IMO. Especially in the average Spec Miata incident. Slapping a wall or a tire barrier, or getting hit on the passenger side, in an accident that you beat the fender out and keep racing, your head still slaps that bar's padding.
The second main conflict (omission really in the NASA rules) is being allowed in the SCCA rule set to attach bracing for the seat mount system to both the floor and the cage on the drivers side of the centerline of the car, and forward of the main hoop, without it counting as cage attachment points.
In the thunderhill accident, the floor was ripped from the rocker box and the rocker box crushed in towards the tunnel, narrowing the drivers side tub and displacing the seat upwards and inwards. I think the design the SCCA rules allow would give that a fighting chance of being a better situation in this accident.
Although, in FIA rally rules you are required to have the lower seat bracing reach the other side of the cage, not just the tunnel. Not sure how much stopping at the tunnel will add to keeping the drivers compartment from crushing, but clearly much less than if I braced past the tunnel to the other side, like ralley car cages we've built.
Interestingly, my customers reactions are to get full containment seats into the cars, which requires more head room, and most FIA seats don't allow a back brace - so the floor needs to be much stronger as well. So, we are using the Ultrashield full containment seat in the first build, which allows for seat back bracing.
Back to the point of this post, I am building 3 cars in the off season using the 2014 SCCA cage rule set which have technicality conflicts with the NASA ruleset, will I have a problem getting NASA logbooks as well???
Thanks,
Kyle Watkins
Sector Purple Racing
Rocky Mountain Division SCCA and NASA