The 1929 Travel Air 4000 N3977, now on display at the Heidrick, served many years as a crop duster in the fields around Lodi. Originally manufactured as a passenger plane, the N3977 was purchased and retrofitted when the four Precissi brothers (Lou, Augie, Joe, and Frank) established the Precissi Flying Service in 1945. To preserve its important contribution to agricultural history, the N3977 is now owned by the California Agricultural Aircraft Association, which loaned it to the Heidrick.
As a crop duster, the N3977 was mainly used to apply sulfur, a fungicide that helped control powdery mildew and pests on Tokay grapes, popular table grapes before the Thompson seedless variety. The N3977 was also used to dust tomatoes, potatoes, corn, and sugar beets – all common crops in the 1950s.
To load the hopper, located in front of the cockpit, the crew piped the contents of 100-pound bags of sulfur (see photo). When loaded, the N3977 could carry a payload of about 1,000 pounds. As the plane flew over the ag fields, the sulphur was air driven through the distributor on the bottom of the plane directly onto the fields. A glass window in the front of the cockpit allowed the pilot to monitor the amount of material left in the hopper.
Because the N3977 carried a fairly small payload, the Precissi brothers set up many small air strips throughout the Lodi area so the plane could land and be reloaded during a job. A flagger was responsible for calling each pass that the pilot made, working with the pilot to coordinate the exact placement of chemicals or seeds (see photo). Together, the flagger and pilot took great care to avoid unwanted drift onto irrigation channels or adjacent properties and to protect any people in the vicinity.
Contemporary ag planes typically include a GPS* unit to guide the drop. Ag planes seeding rice, for example, may seed several varieties in close proximity, each carefully placed by the pilot, with the help of GPS.
*Global Positioning System
Notes: Thanks to Don Precissi for his assistance with this article, the Yolo County Archives for photographs of H.H. Weggers Airplane Seeding and Dusting, and “Serving Agriculture from the Air, the Story of Precissi Flying Service,” The San Joaquin Historian, The San Joaquin County Historical Society, 1990, Vol. 4, No. 1.