breton wrote:On the steering column, I've always had this padded with a piece of rollbar padding. Note that there is an authorized modification in the GCR to cleanly and smoothly cut off the unused portion.
While you can't move the fiberglass seat forward, there's nothing in the rules preventing you from putting in a reasonable amount of foam (though "reasonable" is subjective and not a term published in the GCR.) I recall in the Sports Renault days that we had a very small racer woman from Hawaii that came to race in So Cal, who had a seat insert and head rest custom made to fit the fiberglass seat so she could reach the steering wheel and pedals. This is one area where the rules may need updating, since it's allowed to foam the seat, but not to increase the thickness of the headrest.
I bring up the headrest because that's a critical element as well if you move your head forward in the fiberglass seat, even with the HANS. I believe that one of the most serious injuries sustained in an SR was from a driver who had foamed the seat to move his position forward, but did not pad out the headrest to compensate, and sustained a serious neck injury in a crash. My points are not to discourage building a safe environment but be careful about unintended consequences (e.g. being able top quickly exit the car in the event of a fire.)
The compression fracture is a challenge (I've suffered two in racing accidents; one in a kart and one in the SRF). With a steeper seat angle, more energy is transferred to the lower back, so I'm not sure a more reclined position would be beneficial (though I have since added Confour padding to my Butler seat to offer some cushioning.)
Bob brings up some great points. We're talking about fairly sophisticated safety engineering here and, yes, there can be unintended consequences. In the meantime, my seat is coming out anyway for some work so, in addition to the thigh bolsters I'm already adding, I'll be bolting on the Butler Shoulder Supports:
http://pitstopusa.com/c-132944-cockpit-interior-seats-shoulder-supports-butlerbuilt-shoulder-supports.html
Bob mentioned Confor padding and from what I've learned that's the stuff you want if you're adding foam padding inserts. That's NASA astronaut seat stuff and its big advantage is that it resists permanently compressing -- that's very important -- and offers superior protection over garden variety foam.