See page 2 of this thread
http://www.pprune.org/forums/showthr...5&pagenumber=2
for the text of a recent lecture on flying WW2 fighters which, as well as being interesting in its own right, includes useful comments on grass vs hard runways etc. I am trying to find a very old link to a very clear posting by John Farley about ground looping (I have one thing in common with Mr Farley: I only ever ground loop when I have an audience. Alas, there the comparisons between us as pilots must end. )