Complex sentence: He received a B.S. in mechanical engineering from the University of Wisconsin in 1925 and joined the NACA as an aeronautical engineer at the Langley Aeronautical Laboratory.
Split into simpler sentences: He received a B.S. in mechanical engineering from the University of Wisconsin in 1925. After gradation he joined the NACA as an aeronautical engineer at the Langley Aeronautical Laboratory.