Weasel you are right that formula in the catalog is for static compression.
I have used the on line calculators and they work fine. I am just a sick person that loves to know the old school way of figuring things out.....I found one that looks close on the mopar tech library. I did not have time to sit down and work it out and see if it comes up to the same as the on line calculators.....
I remember the first time i mad a cad drawing that had compound angles i sat with a calculator and figured it all out the long way just to see if the program was right..... he... he... he....It took me a long time but guess what..... the math never changes L.O.L.