Built from the ground up just like the Papac Logging TT-90 -it was all Ross built from the carrier to the tower top fairleads.
The Thunderbird Tower/Carrier Serial Number is T-9055, and bolted to it is Thunderbird TY-90 Hoist Serial Number Y-9051.
The units left the factory as a mated pair sold to Hopkes Logging at Tillamook Oregon on February 24th, 1986