I'm thinking it's not a jet engine. The rear outlet is insufficient. Here is a drawing (scroll down a little) that shows the generator as fitted in the bottom left and a bit larger view in the bottom middle drawing.
http://www.sas1946.com/main/index.php?topic=20946.0
It looks like a match. The difference in color may be due to a hasty installation of a replacement due to malfunction or some crash damage.
Ed