Mark has kindly provided a link to Dr Mitchell's obituary here. And from that, charting his full life and family,:-
'Beyond his professional life, Frank's true passions lay in working with his hands. His love and skill for making intricate and extraordinarily realistic model airplanes was unmatched, with seven of his creations displayed in the Smithsonian's National Air and Space Museum.'
A special skill and leaving a legacy to be appreciated.
Image credit: © 2015 Ken Glass with permission of Dr Frank Mitchell