RD,
Many thanks for the reply. I am trying to put together an article that provides pointers to operators of piston engine helicopters about performance and any rules of thumb and issues they should be aware of. You certainly gave me some good pointers in the post you made....again many thanks.
We all seem to have little snippets and experiences but rarely do we pull all those together and I hope pull at least some of those together in the article (as much as you can in 2000 words).
There's a very good in this month's Heli news about piston engine and turbine engine comparisons.