‘Man in the hot seat’ by Doddy Hay perchance?
An excellent read if you can find a copy. He is very matter of fact about all the injuries he sustained from multiple rides on seats that were sometimes a little over-enthusiastic on the initial acceleration front. It's years since I read it, but I still remember the reported comment from the orthopaedic surgeon looking at an X-ray of his back: "Mr Hay, you have a singularly tatty spine!"
There are many who owe their safe and injury-free ejections to people like Doddy Hay. He would no doubt have been made redundant on health and safety grounds today.