About This File
X-Plane 9 Waco UBF. The Waco 'F' series of biplanes supplanted and then replaced the earlier 'O' series of 1927/33. The 'F' series had an airframe which was smaller and about 450 pounds (200 kg) lighter than the 'O' series, while continuing to provide accommodation for three persons in tandem open cockpits. By A. Lynn Lockrow (Clipwing).