Problem resolved! (Sort of)
That is, I am again able to play Quick Combat, the KW F-86 against the Mig-15, without a CTD every time I score a guns kill on a Mig. The downside is I still haven't tracked down the source of the problem. Let me explain.
I have an external Drive (G:) for backup and storage. I had a backup of CFS2 from sometime ago before my problems started so I restored CFS2 to the G Drive and ran it from there. Presto, I was even able to use the CA-27 Australian F-86 version without CTD on guns kill.
So I'm now in the process of comparing the 2 installs to try to track down what is causing the CTD on the C Drive install. The first thing I noticed was the F-86 model on the G Drive installation was not the latest but an earlier version, so I tried it on the C Drive install but it made no difference. I'm still working on it and it may take a long time but at least I can now shoot down a few Migs when I get the urge.
Thanks to all those who tried to help, especially Hagar and Dirt Man!
Investdude