Hi Bela,
I'm trying to find details (dimensions and ideally drawings) for the seats used in the CAC Wirraway, an Australian production version of the NA-33. So I figured it might make sense to see what seats are in early Texans and Harvards to see if they are similar. Doug MacPhail passed on a couple of pages from Harvard and T6 maintenance manuals, and then I also discovered your reply to
his earlier seat question posted on WiX.
The Wirraway seats look similar to the round-backed Schick Johnson seats, definately nothing like the square Warren Macarthur. In fact they are closer to the Bendix seats in the pics from Mike Robinson on the thread above, with side plates that taper to nothing at their top edge, and round backs on the top of the seat. So some more searching resulted in
finding this diagram, which confirmed some of the dimensions (like the distance between the support tubes).
But while this drawing is very close (and obviously it's a reference standard, not a seat from a particular manufacturer), this is still not exactly the Wirraway seat, since the Wirraway seat has a set of stiffeners on the back of the seat shaped like a triangle pointing upwards.
I also thought the Wirraway seats could be similar to those in the Yale, but after checking
Patrick's restoration at Legend of Aces, its clear they are not the same. I guess NA-33 is still much earlier than NA-64!
Here are some shots of the Wirraway seat, courtesy of Doug MacPhail:
So anyone who can add some more thoughts, feel free!