Willford's spreadsheets are quite good.

Yes they are. If you use/enjoy them, send a note and tell him how
much you like them. Neal spends a lot of time to publish the articles
and spreadsheets, and is not always sure anyone cares. Let him know.
Everyone appreciates being appreciated!

Mail to "editorial at eaa dot org" and put "Attn:Neal Willford" in
the subject line. You kill birds with one stone that way; EAA editors
know you like technical articles, and your thanks get to Neal.

Dan Horton