roys,
Do please continue. I am sure there is a lot of interest in both the T53 and Sigma.
I don't think we have had a direct line before on PPRuNe, to the designer of historic aircraft like these.
The cracked runway in your picture of Sigma looks very familiar. Is it Innisfail, Alberta?
Dave Marsden, who took over Sigma, is a long time member of the Edmonton Soaring Club and a Professor Emeritus at the University of Alberta. He rebuilt Sigma's wing using slotted flaps, based on his experience from his Gemini two-seater.
There is a previous PPRuNe discussion about Sigma
http://www.pprune.org/aviation-histo...area-quiz.html including a link to a talk by Nick Goodhart
Competition Flying In Sigma