In 1944, Bing Crosby was the most famous singer in the US, almost "the king" (years before Elvis), alas he was killed by a propeller blade hurting the fuselage of its airliner in flight after an engine failure, even with no crash at all, and many US civilians feared to go on traveling by plane, as murdering as war, almost (according to the news)... Thus the Lockeed team designed airliners of a new kind: with safe ducted propellers... This has been forgotten today because jet aircraft have made this way so popular...