The Roberts Motor Company of Sandusky, Ohio built the Model 6X engine. An important design objective of this engine was light weight, achieved through the extensive use of aluminum and magnesium alloys in the cylinders and crankcase, a hollow crankshaft, and two-stroke cycle operation (to reduce parts count). Between 1911 and 1912, many noted exhibition pilots used Roberts engines, and more Roberts engines were said to be built than by Hall-Scott and Curtiss combined.

This Roberts 6X engine originally powered Herman Ecker's flying boat of 1912, and is installed in the Ecker flying boat, which is on display at the museum. Ecker patterned his airplane closely after the highly successful Curtiss Model E and F flying boats. However, it bears the hallmarks of a lone builder, long on enthusiasm and ingenuity, but short on resources and access to the latest technology.