Of course the Lockheed Orion was also based on a commercial airliner, the Electra L188. This was the first commercial turboprop airliner. Previous commercial twin combustion engine Electras, the model 10, also had military service as patrol planes. A lengthened version of the original Electra was the Lodestar. My first flight ever was in an Electra in commercial service in 1943. Herman