Dick wrote:

Staring at my empty instrument panel while considering which instruments and
their placement, I got wondering how old time Mail pilots flew if caught in
IFR conditions.

By the 30's, the mail was going by airlines. I assume you mean the old open
cockpit planes of the 20's (like the Pitcairn Mailwing or the earlier Jennie).
A skilled pilot can keep one straight and level by the feel of the relative
wind on his cheeks and the sound of the wind in the wires, combined with the
ball and altimeter. This still isn't as good as a gyro stack, and the accident
rate was high. Lots of the pilots simply put the mail on the train if things
got too bad.

Lindberg discusses some of this in one of his books, and Gann has at least two
novels about the period. I've also read an old book by a veteran mail pilot,
but I have no idea any more what the title was (I checked it out from either
the Knoxville public library or the Bearden High School library in the 60's).

George Patterson
Brute force has an elegance all its own.