This Motorlet M-701 is a centrifugal-flow turbojet, designed and built in Czechoslovakia, and retains its ignition, oiling, and fueling systems. It is a C-500 variant previously modified to run on biofuel for GreenFlight International and was last run circa 2018 using diesel fuel. The 800-pound engine is mounted on a 21-foot test-bed trailer equipped with a fuel tank, control panel, and all necessary components for operation.