As I mentioned, spreadsheets are cool but back of the envelope pretty much gets you within 3%:

~MAC = 0.5*(9.75+7.75) = 8.75" (it's not exactly a MAC but it will do)

Area = MAC*Span = 8.75" * 52" = 455 sq in

If one includes the ailerons at 3/4" width:

Area = (10.5+8.5)*26 = 494 sq in

the same as calculated by thailazer and the spread sheet.

A more accurate effective wing area is likely closer to 19*25 = 475 sq in if one removes two inches of wing span to account for the wing tips. They may even be wider than that so being conservative and assuming an effective wing area of 465 sq in (the mean of the area without ailerons and that without tips but with ailerons), the wing loading at 60 oz (3.75 lbs) would be:

wing loading = 60/3.23 = 18.6 oz/sq ft

That sounds just perfect for a model this size.

I'm actually building a model with a 51-1/4" span and the exact same 465 squares so the magic number of 60 oz was already close to me... [8D]

Looking forward to hearing how she flies!

David.