Chris,
Not a huge amount of difference between the T-6 and Wirraway in terms of performance. The Wirraway's a little bit faster in the cruise I believe. The Wirraway shakes around a lot more than the T-6, I assume due to having a more 'flexible' structure than the T-6 with its aluminium tail cone. Although the T-6 certainly doesn't have the best stall characteristics, the Wirraway is even worse. This last bit leads into my answer to John's questions...
John,
The above comment about stall characteristics might represent an answer as to why the T-6 wings are more sweptback than the early aircraft in the NA-16 family. I know that stalling characteristics were a factor when CAC decided to put washout in the wings - a result of fairly ordinary characteristics of the NA-16 prototype. This is something that I've never had confirmed but I believe they possibly made the sweepback change in an attempt to sedate the stall characteristics.
Another difference between the T-6 and Wirraway wing is the strength. Interestingly enough, a mate said to me over the weekend that the T-6 wing structure is like that of a light Cessna wing compared to the Wirraway.
Wirraway systems are vastly different to those of the T-6. It must be remembered that the Wirraway was derived from an early stage of the NA-16 family with the T-6 being the result of continual development. If Steve Patterson still looks at the WIX, see if he can advise his thoughts of the comparison of systems between the two. I know which aircraft he prefers in that sense!
Have shown below a poor shot of the rear fuselage frame and a couple showing the kind of structure that makes up the fuselage side panels. These were just on my computer anyway so will do the job for now.
Cheers,
Matt