Lockheed Model 10 Electra, NC233Y, Northwest Airlines fleet number 60, prototype, before modification (SDASM) Published on February 24, 2014 in 24 February 1934Full resolution (1846 × 1025) ← Previous Next → Lockheed Model 10 Electra NC233Y at St. Paul, Minnesota, 1934. (San Diego Air and Space Museum Archives)