
Open During Special Events and
By Appointment
THE CALDWELL COLLECTION AT MUSTANG FIELD
1941 Waco ZPF-7:
A Rare Blend of Power and Legacy
NC 32018 was delivered to Unger Aircraft, Inc. of Brunswick, New Jersey July 2, 1941 as storm clouds continued to build over the United States and internal debate over its role in the war in Europe continued to heat up. Five months from the attack on Pearl Harbor the military was ramping up pilot training in anticipation of direct U.S. involvement as fast as possible. Serial Number 5650 would join that training effort after its completion as a UPF 7 by Waco Aircraft Company.
The UPF 7 was the final evolution of the Waco “F” series aircraft which began nearly a decade earlier with the famous RNF. The first of the Waco F models to bear the “7” moniker was actually a “ZPF-7” delivered to Hardy Young Flying Service of Oklahoma City in May of 19037. There were a number of differences between the “Z” models, of which several were built between 1937 and 1940, and the UPF 7 which ultimately became the most produced F model of them all. The biggest differences were the use, on the Z model, of a Jacob’s engine instead of Continental, a covered rear cockpit like the ZPF and YPF 6, and the narrower landing gear Waco had been using on the CPF series of military planes sent to South America. As the U.S. government became the buyer of open cockpit Waco’s for training purposes it specified a 100 inch wide landing gear and an enlarged rear cockpit. NC 32018 retains these later features.
In fact, what makes NC 32018 a “Z” model is merely the addition of the Jacobs R755B2 engine in place of its original Continental. In all other respects it is a UPF 7 with a constant speed propeller. But the greater horsepower of the Jacobs and the variable speed propeller give it significantly improved performance compared to a standard UPF 7 like those in the Collection while retaining the comfort for 21st century pilots of the large rear cockpit and the wide landing gear for easier landing. Restored in 2007 by well known restoration shop Rare Aircraft of Faribault, Minnesota this example is not just stunning with its green and cream livery and streamlined cowl, it is well equipped for today’s flying with modern instrumentation to complement the safety of its Cleveland wheels and brakes.
Rob Lock is a noted restorer of Boeing Stearman biplanes, virtually all of which were also built originally for the pilot training effort during World War II. Not just a huge fan of Stearman’s he has had a multi decade love affair with the Travel Air marque. It’s a joke in antique circles that Travel Air owners and pilots are a different breed than Waco owners. Apparently the two don’t often cross in their dedication to brand. Rob has worked on several Wacos in the “Dream Waco” collection though and it must have rubbed off on him as he purchased his ZPF 7 in the summer of 2024 and flew it to Oklahoma from Washington State. Surely he received some good natured ribbing from Travel Air friends along the way!


The Green Machine










